Lung Motion Model Validation Experiments, Free-Breathing Tissue Densitometry, and Ventilation Mapping using Fast Helical CT Imaging

NASA Astrophysics Data System (ADS)

Dou, Hsiang-Tai

The uncertainties due to respiratory motion present significant challenges to accurate characterization of cancerous tissues both in terms of imaging and treatment. Currently available clinical lung imaging techniques are subject to inferior image quality and incorrect motion estimation, with consequences that can systematically impact the downstream treatment delivery and outcome. The main objective of this thesis is the development of the techniques of fast helical computed tomography (CT) imaging and deformable image registration for the radiotherapy applications in accurate breathing motion modeling, lung tissue density modeling and ventilation imaging. Fast helical CT scanning was performed on 64-slice CT scanner using the shortest available gantry rotation time and largest pitch value such that scanning of the thorax region amounts to just two seconds, which is less than typical breathing cycle in humans. The scanning was conducted under free breathing condition. Any portion of the lung anatomy undergoing such scanning protocol would be irradiated for only a quarter second, effectively removing any motion induced image artifacts. The resulting CT data were pristine volumetric images that record the lung tissue position and density in a fraction of the breathing cycle. Following our developed protocol, multiple fast helical CT scans were acquired to sample the tissue positions in different breathing states. To measure the tissue displacement, deformable image registration was performed that registers the non-reference images to the reference one. In modeling breathing motion, external breathing surrogate signal was recorded synchronously with the CT image slices. This allowed for the tissue-specific displacement to be modeled as parametrization of the recorded breathing signal using the 5D lung motion model. To assess the accuracy of the motion model in describing tissue position change, the model was used to simulate the original high-pitch helical CT scan geometries, employed as ground truth data. Image similarity between the simulated and ground truth scans was evaluated. The model validation experiments were conducted in a patient cohort of seventeen patients to assess the model robustness and inter-patient variation. The model error averaged over multiple tracked positions from several breathing cycles was found to be on the order of one millimeter. In modeling the density change under free breathing condition, the determinant of Jacobian matrix from the registration-derived deformation vector field yielded volume change information of the lung tissues. Correlation of the Jacobian values to the corresponding voxel Housfield units (HU) reveals that the density variation for the majority of lung tissues can be very well described by mass conservation relationship. Different tissue types were identified and separately modeled. Large trials of validation experiments were performed. The averaged deviation between the modeled and the reference lung density was 30 HU, which was estimated to be the background CT noise level. In characterizing the lung ventilation function, a novel method was developed to determine the extent of lung tissue volume change. Information on volume change was derived from the deformable image registration of the fast helical CT images in terms of Jacobian values with respect to a reference image. Assuming the multiple volume change measurements are independently and identically distributed, statistical formulation was derived to model ventilation distribution of each lung voxels and empirical minimum and maximum probability distribution of the Jacobian values was computed. Ventilation characteristic was evaluated as the difference of the expectation value from these extremal distributions. The resulting ventilation map was compared with an independently obtained ventilation image derived directly from the lung intensities and good correlation was found using statistical test. In addition, dynamic ventilation characterization was investigated by estimating the voxel-specific ventilation distribution. Ventilation maps were generated at different percentile levels using the tissue volume expansion metrics.

Different predictive values of interim 18F-FDG PET/CT in germinal center like and non-germinal center like diffuse large B-cell lymphoma.

PubMed

Kim, Jihyun; Lee, Jeong-Ok; Paik, Jin Ho; Lee, Won Woo; Kim, Sang Eun; Song, Yoo Sung

2017-01-01

Diffuse large B-cell lymphoma (DLBCL) is a pathologically heterogeneous disease with different prognoses according to its molecular profiles. Despite the broad usage of 18 F-fluoro-2-dexoxy-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT), previous studies that have investigated the value of interim 18 F-FDG PET/CT in DLBCL have given the controversial results. The purpose of this study was to evaluate the prognostic value of interim 18 F-FDG PET/CT in DLBCL according to germinal center B cell-like (GCB) and non-GCB molecular profiling. We enrolled 118 newly diagnosed DLBCL patients treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP). Interim 18 F-FDG PET/CT scans performed after 2 or 3 cycles of R-CHOP treatment were evaluated based on the Lugano response criteria. Patients were grouped as GCB or non-GCB molecular subtypes according to immunohistochemistry results of CD10, BCL6, and MUM1, based on Hans' algorithm. In total 118 DLBCL patients, 35 % were classified as GCB, and 65 % were classified as non-GCB. Interim PET/CT was negative in 70 %, and positive in 30 %. During the median follow-up period of 23 months, the positive interim 18 F-FDG PET/CT group showed significantly inferior progression free survival (PFS) compared to the negative interim 18 F-FDG PET/CT group (P = 0.0004) in entire patients. A subgroup analysis according to molecular profiling demonstrated significant difference of PFS between the positive and negative interim 18 F-FDG PET groups in GCB subtype of DLBCL (P = 0.0001), but there was no significant difference of PFS between the positive and negative interim 18 F-FDG PET groups in non-GCB subtype of DLBCL. Interim 18 F-FDG PET/CT scanning had a significant predictive value for disease progression in patients with the GCB subtype of DLBCL treated with R-CHOP, but not in those with the non-GCB subtype. Therefore, molecular profiles of DLBCL should be considered for interim 18 F-FDG PET/CT practice.

Microbially mediated carbon cycling at the Cenomanian-Turonian transition in lacustrine environments

NASA Astrophysics Data System (ADS)

Wu, H.; Zhang, S.; Jiang, G.; Underwood, M.; Wan, X.

2009-12-01

The Late Cretaceous Cenomanian-Turonian (C-T) transition records a major ocean anoxic event (OAE2) and a positive carbon isotope excursion. These events have been documented mostly from marine successions and their expression in terrestrial environments is highly desirable. Here we report a high-resolution organic carbon isotope record across the C-T boundary from the Qingshankou Formation (K2qn) of the terrestrial Songliao Basin (SLB) in northeastern China. Samples were collected from the drilled core (SK-1) and cover the bottom 60 m of the K2qn that has been correlated to the C-T transition using the astronomical time scale. The results show a long-term negative δ13Corg excursion superimposed on short-term δ13Corg cycles. Most δ13Corg cycles have a reverse relationship with total organic carbon (TOC) concentration, except at the beginning and the end of the long-term δ13Corg excursion. Spectral analysis of the δ13Corg, TOC and Gamma Ray Logging curves (GR) reveals three distinct cycle bands with the thickness of 14.5-9.0m, 5.8-3.4m and 2.2-1.5m, which were interpreted as the short eccentricity, obliquity, and precession cycles, respectively. The investigated section recorded about 7 short eccentricity and 39 precession cycles. The reverse relationship between TOC and δ13Corg is inconsistent with the general TOC-δ13Corg pattern seen in most lacustrine environments, in which increasing primary productivity (and thus TOC) in the epilimnion results in higher δ13Corg values. In combination with existing biomarker data from K2qn, the TOC-δ13Corg pattern in SLB is better explained by microbially mediated carbon cycling that is astronomically controlled by the precession cycles. During precession minima (summer insolation maxima) periods, intensified precipitation and increased chemical weathering may have led to sustained eutrophication in SLB and the bloom of chemoautotrophic and methanotrophic organisms in the basin. Significant biomass contribution from chemoautotrophic and methanotrophic organisms resulted in lower δ13Corg values. During precession maximum, seasonal changes and reduced nutrient supply kept better water circulation and a lower chemocline. Most organic carbon contribution was from photosynthetic organisms and has relatively higher δ13Corg values. The positive TOC-δ13Corg correlation at the beginning and end of the long-term negative δ13Corg excursion can be interpreted as resulting from the algal/diatom blooms at the onset and ending of the eccentricity cycle, during which high surface water production and a lower chemocline were maintained. The data indicate sustained anoxia/euxinia in the SLB during the time of OAE2, suggesting a paleoclimate event influencing both the marine and terrestrial systems.

Extreme 13C depletions in seawater-derived brines and their implications for the past geochemical carbon cycle

NASA Astrophysics Data System (ADS)

Lazar, Boaz; Erez, Jonathan

1990-12-01

Extreme depletions in the 13C content of the total dissolved inorganic carbon (CT) were found in brines overlying microbial mat communities. Total alkalinity (AT) and CT in the brines suggest that intense photosynthetic activity of the microbial mat communities depletes the CT from the brine. We suggest that this depletion drives a large, kinetic, negative fractionation of carbon isotopes similar to that observed in highly alkaline solutions. In brines of extreme salinity where microbial mat communities no longer exist, the 13C content of the CT increases, probably because photosynthesis no longer dominates the gas-exchange processes. This mechanism explains light carbon-isotope compositions of carbonate rocks from evaporitic sections and bears on the interpretation of δ13C values in bedded stromatolitic limestones that are ca. 3.5 b.y. old.

TH-E-17A-07: Improved Cine Four-Dimensional Computed Tomography (4D CT) Acquisition and Processing Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castillo, S; Castillo, R; Castillo, E

2014-06-15

Purpose: Artifacts arising from the 4D CT acquisition and post-processing methods add systematic uncertainty to the treatment planning process. We propose an alternate cine 4D CT acquisition and post-processing method to consistently reduce artifacts, and explore patient parameters indicative of image quality. Methods: In an IRB-approved protocol, 18 patients with primary thoracic malignancies received a standard cine 4D CT acquisition followed by an oversampling 4D CT that doubled the number of images acquired. A second cohort of 10 patients received the clinical 4D CT plus 3 oversampling scans for intra-fraction reproducibility. The clinical acquisitions were processed by the standard phasemore » sorting method. The oversampling acquisitions were processed using Dijkstras algorithm to optimize an artifact metric over available image data. Image quality was evaluated with a one-way mixed ANOVA model using a correlation-based artifact metric calculated from the final 4D CT image sets. Spearman correlations and a linear mixed model tested the association between breathing parameters, patient characteristics, and image quality. Results: The oversampling 4D CT scans reduced artifact presence significantly by 27% and 28%, for the first cohort and second cohort respectively. From cohort 2, the inter-replicate deviation for the oversampling method was within approximately 13% of the cross scan average at the 0.05 significance level. Artifact presence for both clinical and oversampling methods was significantly correlated with breathing period (ρ=0.407, p-value<0.032 clinical, ρ=0.296, p-value<0.041 oversampling). Artifact presence in the oversampling method was significantly correlated with amount of data acquired, (ρ=-0.335, p-value<0.02) indicating decreased artifact presence with increased breathing cycles per scan location. Conclusion: The 4D CT oversampling acquisition with optimized sorting reduced artifact presence significantly and reproducibly compared to the phase-sorted clinical acquisition.« less

SU-E-J-252: A Motion Algorithm to Extract Physical and Motion Parameters of a Mobile Target in Cone-Beam Computed Tomographic Imaging Retrospective to Image Reconstruction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ali, I; Ahmad, S; Alsbou, N

Purpose: A motion algorithm was developed to extract actual length, CT-numbers and motion amplitude of a mobile target imaged with cone-beam-CT (CBCT) retrospective to image-reconstruction. Methods: The motion model considered a mobile target moving with a sinusoidal motion and employed three measurable parameters: apparent length, CT number level and gradient of a mobile target obtained from CBCT images to extract information about the actual length and CT number value of the stationary target and motion amplitude. The algorithm was verified experimentally with a mobile phantom setup that has three targets with different sizes manufactured from homogenous tissue-equivalent gel material embeddedmore » into a thorax phantom. The phantom moved sinusoidal in one-direction using eight amplitudes (0–20mm) and a frequency of 15-cycles-per-minute. The model required imaging parameters such as slice thickness, imaging time. Results: This motion algorithm extracted three unknown parameters: length of the target, CT-number-level, motion amplitude for a mobile target retrospective to CBCT image reconstruction. The algorithm relates three unknown parameters to measurable apparent length, CT-number-level and gradient for well-defined mobile targets obtained from CBCT images. The motion model agreed with measured apparent lengths which were dependent on actual length of the target and motion amplitude. The cumulative CT-number for a mobile target was dependent on CT-number-level of the stationary target and motion amplitude. The gradient of the CT-distribution of mobile target is dependent on the stationary CT-number-level, actual target length along the direction of motion, and motion amplitude. Motion frequency and phase did not affect the elongation and CT-number distributions of mobile targets when imaging time included several motion cycles. Conclusion: The motion algorithm developed in this study has potential applications in diagnostic CT imaging and radiotherapy to extract actual length, size and CT-numbers distorted by motion in CBCT imaging. The model provides further information about motion of the target.« less

The retrospective binning method improves the consistency of phase binning in respiratory-gated PET/CT

NASA Astrophysics Data System (ADS)

Didierlaurent, D.; Ribes, S.; Batatia, H.; Jaudet, C.; Dierickx, L. O.; Zerdoud, S.; Brillouet, S.; Caselles, O.; Courbon, F.

2012-12-01

This study assesses the accuracy of prospective phase-gated PET/CT data binning and presents a retrospective data binning method that improves image quality and consistency. Respiratory signals from 17 patients who underwent 4D PET/CT were analysed to evaluate the reproducibility of temporal triggers used for the standard phase-based gating method. Breathing signals were reprocessed to implement retrospective PET data binning. The mean and standard deviation of time lags between automatic triggers provided by the Real-time Position Management (RPM, Varian) gating device and inhalation peaks derived from respiratory curves were computed for each patient. The total number of respiratory cycles available for 4D PET/CT according to the binning mode (prospective versus retrospective) was compared. The maximum standardized uptake value (SUVmax), biological tumour volume (BTV) and tumour trajectory measures were determined from the PET/CT images of five patients. Compared to retrospective binning (RB), prospective gating approach led to (i) a significant loss in breathing cycles (15%) and (ii) the inconsistency of data binning due to temporal dispersion of triggers (average 396 ms). Consequently, tumour characterization could be impacted. In retrospective mode, SUVmax was up to 27% higher, where no significant difference appeared in BTV. In addition, prospective mode gave an inconsistent spatial location of the tumour throughout the bins. Improved consistency with breathing patterns and greater motion amplitude of the tumour centroid were observed with retrospective mode. The detection of the tumour motion and trajectory was improved also for small temporal dispersion of triggers. This study shows that the binning mode could have a significant impact on 4D PET images. The consistency of triggers with breathing signals should be checked before clinical use of gated PET/CT images, and our RB method improves 4D PET/CT image quantification.

Comparison of helical and cine acquisitions for 4D-CT imaging with multislice CT.

PubMed

Pan, Tinsu

2005-02-01

We proposed a data sufficiency condition (DSC) for four-dimensional-CT (4D-CT) imaging on a multislice CT scanner, designed a pitch factor for a helical 4D-CT, and compared the acquisition time, slice sensitivity profile (SSP), effective dose, ability to cope with an irregular breathing cycle, and gating technique (retrospective or prospective) of the helical 4D-CT and the cine 4D-CT on the General Electric (GE) LightSpeed RT (4-slice), Plus (4-slice), Ultra (8-slice) and 16 (16-slice) multislice CT scanners. To satisfy the DSC, a helical or cine 4D-CT acquisition has to collect data at each location for the duration of a breathing cycle plus the duration of data acquisition for an image reconstruction. The conditions for the comparison were 20 cm coverage in the cranial-caudal direction, a 4 s breathing cycle, and half-scan reconstruction. We found that the helical 4D-CT has the advantage of a shorter scan time that is 10% shorter than that of the cine 4D-CT, and the disadvantages of 1.8 times broadening of SSP and requires an additional breathing cycle of scanning to ensure an adequate sampling at the start and end locations. The cine 4D-CT has the advantages of maintaining the same SSP as slice collimation (e.g., 8 x 2.5 mm slice collimation generates 2.5 mm SSP in the cine 4D-CT as opposed to 4.5 mm in the helical 4D-CT) and a lower dose by 4% on the 8- and 16-slice systems, and 8% on the 4-slice system. The advantage of faster scanning in the helical 4D-CT will diminish if a repeat scan at the location of a breathing irregularity becomes necessary. The cine 4D-CT performs better than the helical 4D-CT in the repeat scan because it can scan faster and is more dose efficient.

Naturally acquired bovine besnoitiosis: Differential distribution of parasites in the skin of chronically infected cattle.

PubMed

Schares, G; Langenmayer, M C; Majzoub-Altweck, M; Scharr, J C; Gentile, A; Maksimov, A; Schares, S; Conraths, F J; Gollnick, N S

2016-01-30

Bovine besnoitiosis is caused by Besnoitia besnoiti, an apicomplexan parasite closely related to Toxoplasma gondii and Neospora caninum. In the acute stage of besnoitiosis, cattle suffer from pyrexia, swollen lymph nodes, anorexia and subcutaneous edema. In the chronic stage, tissue cysts are formed in a variety of tissues including the skin. Knowledge about the distribution of tissue cysts of different parts of the skin of infected animals is scarce. Four chronically infected cattle were euthanized and skin samples were taken from a total of 77 standardized cutaneous locations per animal. Portions of the dermis were taken, from which DNA was extracted and examined by real-time PCR. Cycle of transition (Ct) values reflecting the amount of parasite DNA in the samples were determined. For statistical analysis, samples were attributed to 11 larger skin regions ('OuterHindlegDistal', 'Rump, ForelegMiddle', 'NoseFrontEars', 'CheekEye', 'SideLowerPart', 'ForelegDistal', 'SideUpperPart', 'LegsInner', 'VentralHeadNeck', 'DorsalNeckWithersBackTail'). While all samples revealed a positive result in three female cattle, only 63.6% (49/77) of the samples of a bull showed positive results. For statistical analysis, a Ct value of 45 was assumed for samples with a negative result. The dams showed median Ct values of 16.1, 17.5 and 19.4, while in skin samples of the bull a median Ct value of 37.6 was observed. To determine the differences in DNA concentrations between different locations of the skin of the animals, a relative Ct (relCt) was determined by subtracting for each animal indv the MedianCtindv from each sample Ct. Analyses of the relCt values showed that the highest relative parasite DNA concentrations were observed in the categories 'OuterHindlegDistal', 'Rump', 'ForelegMiddle' and 'NoseFrontEars'. The relCt values in these categories differed statistically significantly from those determined for the categories 'VentralHeadNeck' and 'DorsalNeckWithersBackTail'. The analysis showed clear differences in the distribution and the detectability of parasite DNA in the skin of cattle infected with B. besnoiti. In all four animals, samples from the 'Rump' region (Regio fermoris) showed high parasite DNA concentrations. Because this region is also easily accessible for veterinarians, this skin location appears to be optimal for taking skin biopsies for detection or isolation of B. besnoiti. Copyright © 2015 Elsevier B.V. All rights reserved.

Neoadjuvant chemotherapy in breast cancer: prediction of pathologic response with PET/CT and dynamic contrast-enhanced MR imaging--prospective assessment.

PubMed

Tateishi, Ukihide; Miyake, Mototaka; Nagaoka, Tomoaki; Terauchi, Takashi; Kubota, Kazunori; Kinoshita, Takayuki; Daisaki, Hiromitsu; Macapinlac, Homer A

2012-04-01

To clarify whether fluorine 18 ((18)F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging performed after two cycles of neoadjuvant chemotherapy (NAC) can be used to predict pathologic response in breast cancer. Institutional human research committee approval and written informed consent were obtained. Accuracy after two cycles of NAC for predicting pathologic complete response (pCR) was examined in 142 women (mean age, 57 years: range, 43-72 years) with histologically proved breast cancer between December 2005 and February 2009. Quantitative PET/CT and DCE MR imaging were performed at baseline and after two cycles of NAC. Parameters of PET/CT and of blood flow and microvascular permeability at DCE MR were compared with pathologic response. Patients were also evaluated after NAC by using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 based on DCE MR measurements and European Organization for Research and Treatment of Cancer (EORTC) criteria and PET Response Criteria in Solid Tumors (PERCIST) 1.0 based on PET/CT measurements. Multiple logistic regression analyses were performed to examine continuous variables at PET/CT and DCE MR to predict pCR, and diagnostic accuracies were compared with the McNemar test. Significant decrease from baseline of all parameters at PET/CT and DCE MR was observed after NAC. Therapeutic response was obtained in 24 patients (17%) with pCR and 118 (83%) without pCR. Sensitivity, specificity, and accuracy to predict pCR were 45.5%, 85.5%, and 82.4%, respectively, with RECIST and 70.4%, 95.7%, and 90.8%, respectively, with EORTC and PERCIST. Multiple logistic regression revealed three significant independent predictors of pCR: percentage maximum standardized uptake value (%SUV(max)) (odds ratio [OR], 1.22; 95% confidence interval [CI]: 1.11, 1.34; P < .0001), percentage rate constant (%k(ep)) (OR, 1.07; CI: 1.03, 1.12; P = .002), and percentage area under the time-intensity curve over 90 seconds (%AUC(90)) (OR, 1.04; CI: 1.01, 1.07; P = .048). When diagnostic accuracies are compared, PET/CT is superior to DCE MR for the prediction of pCR (%SUV(max) [90.1%] vs %κ(ep) [83.8%] or %AUC(90) [76.8%]; P < .05). The sensitivities of %SUV(max) (66.7%), %k(ep) (51.7%), and %AUC(90) (50.0%) at (18)F-FDG PET/CT and DCE MR after two cycles of NAC are not acceptable, but the specificities (96.4%, 92.0%, and 95.2%, respectively) are high for stratification of pCR cases in breast cancer. © RSNA, 2012.

[Development of Audio Indicator System for Respiratory Dynamic CT Imaging].

PubMed

Muramatsu, Shun; Moriya, Hiroshi; Tsukagoshi, Shinsuke; Yamada, Norikazu

We created the device, which can conduct a radiological technologist's voice to a subject during CT scanning. For 149 lung cancer, dynamic respiratory CT were performed. 92 cases were performed using this device, the others were without this device. The respiratory cycle and respiratory amplitude were analyzed from the lung density. A stable respirating cycle was obtained by using the audio indicator system. The audio indicator system is useful for respiratory dynamic CT.

Scope for energy improvement for hospital imaging services in the USA.

PubMed

Esmaeili, Amin; Twomey, Janet M; Overcash, Michael R; Soltani, Seyed A; McGuire, Charles; Ali, Kamran

2015-04-01

To aid radiologists by measuring the carbon footprint of CT scans by quantifying in-hospital and out-of-hospital energy use and to assess public health impacts. The study followed a standard life cycle assessment protocol to measure energy from a CT scan then expanding to all hospital electrical energy related to CT usage. In addition, all the fuel energy used to generate electricity and to manufacture the CT consumables was measured. The study was conducted at two hospitals. The entire life cycle energy for a CT scan was 24-34 kWh of natural resource energy per scan. The actual active patient scan energy that produces the images is only about 1.6% of this total life cycle energy. This large multiplier to get total CT energy is a previously undocumented environmental response to the direct radiology order for a patient CT scan. The CT in-hospital energy related to idle periods, where the machine is on but no patients are being scanned and is 14-30-fold higher than the energy used for the CT image. The in-hospital electrical energy of a CT scan makes up only about 25% of the total energy footprint. The rest is generated outside the hospital: 54-62% for generation and transmission of the electricity, while 13-22% is for all the energy to make the consumables. Different CT scanners have some influences on the results and could help guide purchase of CT equipment. The transparent, detailed life cycle approach allows the data from this study to be used by radiologists to examine details of both direct and of unseen energy impacts of CT scans. The public health (outside-the-hospital) impact (including the patients receiving a CT) needs to be measured and included. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Prospective evaluation of [11C]Choline PET/CT in therapy response assessment of standardized docetaxel first-line chemotherapy in patients with advanced castration refractory prostate cancer.

PubMed

Schwarzenböck, Sarah M; Eiber, Matthias; Kundt, Günther; Retz, Margitta; Sakretz, Monique; Kurth, Jens; Treiber, Uwe; Nawroth, Roman; Rummeny, Ernst J; Gschwend, Jürgen E; Schwaiger, Markus; Thalgott, Mark; Krause, Bernd J

2016-11-01

The aim of this study was to prospectively evaluate the value of [ 11 C] Choline PET/CT in monitoring early and late response to a standardized first-line docetaxel chemotherapy in castration refractory prostate cancer (mCRPC) patients. Thirty-two patients were referred for [ 11 C] Choline PET/CT before the start of docetaxel chemotherapy, after one and ten chemotherapy cycles (or - in case of discontinuation - after the last administered cycle) for therapy response assessment. [ 11 C] Choline uptake (SUV max , SUV mean ), CT derived Houndsfield units (HU max , HU mean ), and volume of bone, lung, and nodal metastases and local recurrence were measured semi-automatically at these timepoints. Change in SUV max , SUV mean , HU max , HU mean, and volume was assessed between PET 2 and 1 (early response assessment, ERA) and PET 3 and 1 (late response assessment, LRA) on a patient and lesion basis. Results of PET/CT were compared to clinically used RECIST 1.1 and clinical criteria based therapy response assessment including PSA for defining progressive disease (PD) and non-progressive disease (nPD), respectively. Relationships between changes of SUV max and SUV mean (early and late) and changes of PSA early and PSA late were evaluated. Prognostic value of initial SUV max and SUV mean was assessed. Statistical analyses were performed using SPSS. In the patient-based ERA and LRA there were no statistically significant differences in change of choline uptake, HU, and volume between PD and nPD applying RECIST or clinical response criteria. In the lesion-based ERA, decrease in choline uptake of bone metastases was even higher in PD (applying RECIST criteria), whereas in LRA the decrease was higher in nPD (applying clinical criteria). There were only significant correlations between change in choline uptake and PSA in ERA in PD, in LRA no significant correlations were discovered. Initial SUV max and SUV mean were statistically significantly higher in nPD (applying clinical criteria). There is no significant correlation between change in choline uptake in [ 11 C] Choline PET/CT and clinically routinely used objective response assessment during the early and late course of docetaxel chemotherapy. Therefore, [ 11 C] Choline PET/CT seems to be of limited use in therapy response assessment in standardized first-line chemotherapy in mCRPC patients.

Evaluation of BD MAX Staph SR Assay for Differentiating Between Staphylococcus aureus and Coagulase-Negative Staphylococci and Determining Methicillin Resistance Directly From Positive Blood Cultures.

PubMed

Lee, Jaewoong; Park, Yeon Joon; Park, Dong Jin; Park, Kang Gyun; Lee, Hae Kyung

2017-01-01

We evaluated the performance of the BD MAX StaphSR Assay (SR assay; BD, USA) for direct detection of Staphylococcus aureus and methicillin resistance not only in S. aureus but also in coagulase-negative Staphylococci (CNS) from positive blood cultures. From 228 blood culture bottles, 103 S. aureus [45 methicillin-resistant S. aureus (MRSA), 55 methicillin-susceptible S. aureus (MSSA), 3 mixed infections (1 MRSA+Enterococcus faecalis, 1 MSSA+MRCNS, 1 MSSA+MSCNS)], and 125 CNS (102 MRCNS, 23 MSCNS) were identified by Vitek 2. For further analysis, we obtained the cycle threshold (Ct) values from the BD MAX system software to determine an appropriate cutoff value. For discrepancy analysis, conventional mecA/mecC PCR and oxacillin minimum inhibitory concentrations (MICs) were determined. Compared to Vitek 2, the SR assay identified all 103 S. aureus isolates correctly but failed to detect methicillin resistance in three MRSA isolates. All 55 MSSA isolates were correctly identified by the SR assay. In the concordant cases, the highest Ct values for nuc, mecA, and mec right-extremity junction (MREJ) were 25.6, 22, and 22.2, respectively. Therefore, we selected Ct values from 0-27 as a range of positivity, and applying this cutoff, the sensitivity/specificity of the SR assay were 100%/100% for detecting S. aureus, and 97.9%/98.1% and 99.0%/95.8% for detecting methicillin resistance in S. aureus and CNS, respectively. We propose a Ct cutoff value for nuc/mec assay without considering MREJ because mixed cultures of MSSA and MRCNS were very rare (0.4%) in the positive blood cultures.

Estimation of critical end-test torque using neuromuscular electrical stimulation of the quadriceps in humans.

PubMed

Janzen, Natalie R; Hight, Robert E; Patel, Darshit S; Campbell, Jason A; Larson, Rebecca D; Black, Christopher D

2018-05-02

Characterization of critical power/torque (CP/CT) during voluntary exercise requires maximal effort, making difficult for those with neuromuscular impairments. To address this issue we sought to determine if electrically stimulated intermittent isometric exercise resulted in a critical end-test torque (ETT) that behaved similar to voluntary CT. In the first experiment participants (n = 9) completed four bouts of stimulated exercise at a 3:2 duty cycle, at frequencies of 100, 50, 25 Hz, and a low frequency below ETT (Sub-ETT; ≤ 15 Hz). The second experiment (n = 20) consisted of four bouts at a 2:2 duty cycle-two bouts at 100 Hz, one at an intermediate frequency (15-30 Hz), and one at Sub-ETT. The third experiment (n = 12) consisted of two bouts at 50 Hz at a 3:2 duty* cycle with proximal blood flow occlusion during one of the bouts. ETT torque was similar (p ≥ 0.43) within and among stimulation frequencies in experiment 1. No fatigue was observed during the Sub-ETT bouts (p > 0.05). For experiment 2, ETT was similar at 100 Hz and at the intermediate frequency (p ≥ 0.29). Again, Sub-ETT stimulation did not result in fatigue (p > 0.05). Altering oxygen delivery by altering the duty cycle (3:2 vs. 2:2; p = 0.02) and by occlusion (p < 0.001) resulted in lower ETT values. Stimulated exercise resulted in an ETT that was consistent from day-to-day and similar regardless of initial torque, as long as that torque exceeded ETT, and was sensitive to oxygen delivery. As such we propose it represents a parameter similar to voluntary CT.

The Development of a Cognitive Tool for Teaching and Learning Fractions in the Mathematics Classroom: A Design-Based Study

ERIC Educational Resources Information Center

Kong, S. C.

2008-01-01

Two cycles of design-based research of a cognitive tool (CT) for teaching fractions have been completed. Following the success of a quasi-experimental study of the enhanced CT derived from the second cycle of design-based research, this article reports the findings of a pre-test-post-test control group empirical study using the enhanced CT in the…

xCT expression reduces the early cell cycle requirement for calcium signaling

PubMed Central

Lastro, Michele; Kourtidis, Antonis; Farley, Kate; Conklin, Douglas S.

2009-01-01

Calcium has long been recognized as an important regulator of cell cycle transitions although the mechanisms are largely unknown. A functional genomic screen has identified genes involved in the regulation of early cell cycle progression by calcium. These genes when overexpressed confer the ability to bypass the G1/S arrest induced by Ca2+- channel antagonists in mouse fibroblasts. Overexpression of the cystine-glutamate exchanger, xCT, had the greatest ability to evade calcium antagonist-induced cell cycle arrest. xCT carries out the rate limiting step of glutathione synthesis in many cell types and is responsible for the uptake of cystine in most human cancer cell lines. Functional analysis indicates that the cystine uptake activity of xCT overcomes the G1/S arrest induced by Ca2+- channel antagonists by bypassing the requirement for calcium signaling. Since cells overexpressing xCT were found to have increased levels and activity of the AP-1 transcription factor in G1, redox stimulation of AP-1 activity accounts for the observed growth of these cells in the presence of calcium channel antagonists. These results suggest that reduced calcium signaling impairs AP-1 activation and that xCT expression may directly affect cell proliferation. PMID:18054200

The role of interim 18F-FDG PET/CT in prediction of response to ipilimumab treatment in metastatic melanoma.

PubMed

Sachpekidis, Christos; Anwar, Hoda; Winkler, Julia; Kopp-Schneider, Annette; Larribere, Lionel; Haberkorn, Uwe; Hassel, Jessica C; Dimitrakopoulou-Strauss, Antonia

2018-07-01

The aim of the present study was to assess the value of interim 18 F-FDG PET/CT performed after the first two cycles of ipilimumab treatment in the prediction of the final clinical response to this type of immunotherapy. The study group comprised 41 patients with unresectable metastatic melanoma scheduled for ipilimumab therapy. Whole-body 18 F-FDG PET/CT was performed before the start of ipilimumab treatment (baseline PET/CT) and after the initial two cycles of ipilimumab treatment (interim PET/CT). Evaluation of patient response to treatment was based on the European Organization for Research and Treatment of Cancer (EORTC) 1999 criteria for PET as well as the recently proposed PET Response Evaluation Criteria for Immunotherapy (PERCIMT). The patients' best clinical response, assessed at a median of 21.4 months (range 6.3-41.9 months) was used as reference. According to their best clinical response, the patients were divided into two groups: those showing clinical benefit (CB) including stable disease, partial response and complete response (31 patients), and those showing no clinical benefit (no-CB including progressive disease (10 patients). According to the EORTC criteria, interim PET/CT demonstrated progressive metabolic disease (PMD) in 20 patients, stable metabolic disease (SMD) in 11 patients, partial metabolic response (PMR) in 8 patients, and complete metabolic response (CMR) in 2 patients. According to the PERCIMT, interim PET/CT demonstrated PMD in 9 patients, SMD in 24 patients, PMR in 6 patients and CMR in 2 patients. On the basis of the interim PET, the patients were divided in a similar manner to the division according to clinical response into those showing metabolic benefit (MB) including SMD, PMR and CMR, and those showing no metabolic benefit (no-MB) including PMD. According to this dichotomization, the EORTC criteria showed a sensitivity (correctly predicting CB) of 64.5%, a specificity (correctly predicting no-CB) of 90.0%, a positive predictive value (PPV) of 95.2%, a negative predictive value (NPV) of 45.0% and an accuracy of 70.7% in predicting best clinical response. The PERCIMT showed a sensitivity of 93.6%, a specificity of 70.0%, a PPV of 90.6%, a NPV of 77.8% and an accuracy of 87.8%. The McNemar test showed that the PERCIMT had a significantly higher sensitivity than EORTC criteria (p = 0.004), while there was no significant difference in specificity (p = 0.5). The agreement between the two sets of criteria was poor (McNemar test p = 0.001, and accordingly kappa = 0.46). The application of the recently proposed PERCIMT to interim 18 F-FDG PET/CT provides a more sensitive predictor of final clinical response to immunotherapy than the application of the EORTC criteria in patients with metastatic melanoma.

Fluorine-18-fluorocholine PET/CT parameters predictive for hematological toxicity to radium-223 therapy in castrate-resistant prostate cancer patients with bone metastases: a pilot study.

PubMed

Vija Racaru, Lavinia; Sinigaglia, Mathieu; Kanoun, Salim; Ben Bouallègue, Fayçal; Tal, Ilan; Brillouet, Sévérine; Bauriaud-Mallet, Mathilde; Zerdoud, Slimane; Dierickx, Lawrence; Vallot, Delphine; Caselles, Olivier; Gabiache, Erwan; Pascal, Pierre; Courbon, Frederic

2018-05-21

This study aims to predict hematological toxicity induced by Ra therapy. We investigated the value of metabolically active bone tumor volume (MBTV) and total bone lesion activity (TLA) calculated on pretreatment fluorine-18-fluorocholine (F-FCH) PET/CT in castrate-resistant prostate cancer (CRPC) patients with bone metastases treated with Ra radionuclide therapy. F-FCH PET/CT imaging was performed in 15 patients with CRPC before treatment with Ra. Bone metastatic disease was quantified on the basis of the maximum standardized uptake value (SUV), total lesion activity (TLA=MBTV×SUVmean), or MBTV/height (MBTV/H) and TLA/H. F-FCH PET/CT bone tumor burden and activity were analyzed to identify which parameters could predict hematological toxicity [on hemoglobin (Hb), platelets (PLTs), and lymphocytes] while on Ra therapy. Pearson's correlation was used to identify the correlations between age, prostate-specific antigen, and F-FCH PET parameters. MBTV ranged from 75 to 1259 cm (median: 392 cm). TLA ranged from 342 to 7198 cm (median: 1853 cm). Patients benefited from two to six cycles of Ra (n=56 cycles in total). At the end of Ra therapy, five of the 15 (33%) patients presented grade 2/3 toxicity on Hb and lymphocytes, whereas three of the 15 (20%) patients presented grade 2/3 PLT toxicity.Age was correlated negatively with both MBTV (r=-0.612, P=0.015) and TLA (r=-0.596, P=0.018). TLA, TLA/H, and MBTV/H predicted hematological toxicity on Hb, whereas TLA/H and MBTV/H predicted toxicity on PLTs at the end of Ra cycles. Receiver operating characteristic curve analysis allowed to define the cutoffs for MBTV (915 cm) and TLA (4198 cm) predictive for PLT toxicity, with an accuracy of 0.92 and 0.99. Tumor bone burden calculation is feasible with F-FCH PET/CT with freely available open-source software. In this pilot study, baseline F-FCH PET/CT markers (TLA, MBTV) have shown abilities to predict Hb and PLT toxicity after Ra therapy and could be explored for patient selection and treatment optimization.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0/.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, S; Yuen, C; Huang, V

Purpose: In this abstract we implement and validate a 4D VMAT Acuros XB dose calculation using Gafchromic film. Special attention is paid to the physical material assignment in the CT dataset and to reported dose to water and dose to medium. Methods: A QUASAR phantom with a 3 cm sinusoidal tumor motion and 5 second period was scanned using 4D computed tomography. A CT was also obtained of the static QUASAR phantom with the tumor at the central position. A VMAT plan was created on the average CT dataset and was delivered on a Varian TrueBeam linear accelerator. The trajectorymore » log file from this treatment was acquired and used to create 10 VMAT subplans (one for each portion of the breathing cycle). Motion for each subplan was simulated by moving the beam isocentre in the superior/inferior direction in the Treatment Planning System on the static CT scan. The 10 plans were calculated (both dose to medium and dose to water) and summed for 1) the original HU values from the static CT scan and 2) the correct physical material assignment in the CT dataset. To acquire a breathing phase synchronized film measurements the trajectory log was used to create a VMAT delivery plan which includes dynamic couch motion using the Developer Mode. Three different treatment start phases were investigated (mid inhalation, full inhalation and full exhalation). Results: For each scenario the coronal dose distributions were measured using Gafchromic film and compared to the corresponding calculation with Film QA Pro Software using a Gamma test with a 3%/3mm distance to agreement criteria. Good agreement was found between calculation and measurement. No statistically significant difference in agreement was found between calculations to original HU values vs calculations to over-written (material-assigned) HU values. Conclusion: The investigated 4D dose calculation method agrees well with measurement.« less

Surface Roughness of Composite Resins after Simulated Toothbrushing with Different Dentifrices.

PubMed

Monteiro, Bruna; Spohr, Ana Maria

2015-07-01

The aim of the study was to evaluate, in vitro, the surface roughness of two composite resins submitted to simulated toothbrushing with three different dentifrices. Totally, 36 samples of Z350XT and 36 samples of Empress Direct were built and randomly divided into three groups (n = 12) according to the dentifrice used (Oral-B Pro-Health Whitening [OBW], Colgate Sensitive Pro-Relief [CS], Colgate Total Clean Mint 12 [CT12]). The samples were submitted to 5,000, 10,000 or 20,000 cycles of simulated toothbrushing. After each simulated period, the surface roughness of the samples was measured using a roughness tester. According to three-way analysis of variance, dentifrice (P = 0.044) and brushing time (P = 0.000) were significant. The composite resin was not significant (P = 0.381) and the interaction among the factors was not significant (P > 0.05). The mean values of the surface roughness (µm) followed by the same letter represent no statistical difference by Tukey's post-hoc test (P <0.05): Dentifrice: CT12 = 0.269(a); CS Pro- Relief = 0.300(ab); OBW = 0.390(b). Brushing time: Baseline = 0,046ª; 5,000 cycles = 0.297(b); 10,000 cycles = 0.354(b); 20,000 cycles = 0.584(c). Z350 XT and Empress Direct presented similar surface roughness after all cycles of simulated toothbrushing. The higher the brushing time, the higher the surface roughness of composite resins. The dentifrice OBW caused a higher surface roughness in both composite resins.

Tumor invasiveness defined by IASLC/ATS/ERS classification of ground-glass nodules can be predicted by quantitative CT parameters.

PubMed

Zhou, Qian-Jun; Zheng, Zhi-Chun; Zhu, Yong-Qiao; Lu, Pei-Ji; Huang, Jia; Ye, Jian-Ding; Zhang, Jie; Lu, Shun; Luo, Qing-Quan

2017-05-01

To investigate the potential value of CT parameters to differentiate ground-glass nodules between noninvasive adenocarcinoma and invasive pulmonary adenocarcinoma (IPA) as defined by IASLC/ATS/ERS classification. We retrospectively reviewed 211 patients with pathologically proved stage 0-IA lung adenocarcinoma which appeared as subsolid nodules, from January 2012 to January 2013 including 137 pure ground glass nodules (pGGNs) and 74 part-solid nodules (PSNs). Pathological data was classified under the 2011 IASLC/ATS/ERS classification. Both quantitative and qualitative CT parameters were used to determine the tumor invasiveness between noninvasive adenocarcinomas and IPAs. There were 154 noninvasive adenocarcinomas and 57 IPAs. In pGGNs, CT size and area, one-dimensional mean CT value and bubble lucency were significantly different between noninvasive adenocarcinomas and IPAs on univariate analysis. Multivariate regression and ROC analysis revealed that CT size and one-dimensional mean CT value were predictive of noninvasive adenocarcinomas compared to IPAs. Optimal cutoff value was 13.60 mm (sensitivity, 75.0%; specificity, 99.6%), and -583.60 HU (sensitivity, 68.8%; specificity, 66.9%). In PSNs, there were significant differences in CT size and area, solid component area, solid proportion, one-dimensional mean and maximum CT value, three-dimensional (3D) mean CT value between noninvasive adenocarcinomas and IPAs on univariate analysis. Multivariate and ROC analysis showed that CT size and 3D mean CT value were significantly differentiators. Optimal cutoff value was 19.64 mm (sensitivity, 53.7%; specificity, 93.9%), -571.63 HU (sensitivity, 85.4%; specificity, 75.8%). For pGGNs, CT size and one-dimensional mean CT value are determinants for tumor invasiveness. For PSNs, tumor invasiveness can be predicted by CT size and 3D mean CT value.

Multicenter evaluation of molecular and culture-dependent diagnostics for Shigella species and Entero-invasive Escherichia coli in the Netherlands.

PubMed

van den Beld, Maaike J C; Friedrich, Alexander W; van Zanten, Evert; Reubsaet, Frans A G; Kooistra-Smid, Mirjam A M D; Rossen, John W A

2016-12-01

An inter-laboratory collaborative trial for the evaluation of diagnostics for detection and identification of Shigella species and Entero-invasive Escherichia coli (EIEC) was performed. Sixteen Medical Microbiological Laboratories (MMLs) participated. MMLs were interviewed about their diagnostic methods and a sample panel, consisting of DNA-extracts and spiked stool samples with different concentrations of Shigella flexneri, was provided to each MML. The results of the trial showed an enormous variety in culture-dependent and molecular diagnostic techniques currently used among MMLs. Despite the various molecular procedures, 15 out of 16 MMLs were able to detect Shigella species or EIEC in all the samples provided, showing that the diversity of methods has no effect on the qualitative detection of Shigella flexneri. In contrast to semi quantitative analysis, the minimum and maximum values per sample differed by approximately five threshold cycles (Ct-value) between the MMLs included in the study. This indicates that defining a uniform Ct-value cut-off for notification to health authorities is not advisable. Copyright © 2016 Elsevier B.V. All rights reserved.

Dose calculation with respiration-averaged CT processed from cine CT without a respiratory surrogate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riegel, Adam C.; Ahmad, Moiz; Sun Xiaojun

2008-12-15

Dose calculation for thoracic radiotherapy is commonly performed on a free-breathing helical CT despite artifacts caused by respiratory motion. Four-dimensional computed tomography (4D-CT) is one method to incorporate motion information into the treatment planning process. Some centers now use the respiration-averaged CT (RACT), the pixel-by-pixel average of the ten phases of 4D-CT, for dose calculation. This method, while sparing the tedious task of 4D dose calculation, still requires 4D-CT technology. The authors have recently developed a means to reconstruct RACT directly from unsorted cine CT data from which 4D-CT is formed, bypassing the need for a respiratory surrogate. Using RACTmore » from cine CT for dose calculation may be a means to incorporate motion information into dose calculation without performing 4D-CT. The purpose of this study was to determine if RACT from cine CT can be substituted for RACT from 4D-CT for the purposes of dose calculation, and if increasing the cine duration can decrease differences between the dose distributions. Cine CT data and corresponding 4D-CT simulations for 23 patients with at least two breathing cycles per cine duration were retrieved. RACT was generated four ways: First from ten phases of 4D-CT, second, from 1 breathing cycle of images, third, from 1.5 breathing cycles of images, and fourth, from 2 breathing cycles of images. The clinical treatment plan was transferred to each RACT and dose was recalculated. Dose planes were exported at orthogonal planes through the isocenter (coronal, sagittal, and transverse orientations). The resulting dose distributions were compared using the gamma ({gamma}) index within the planning target volume (PTV). Failure criteria were set to 2%/1 mm. A follow-up study with 50 additional lung cancer patients was performed to increase sample size. The same dose recalculation and analysis was performed. In the primary patient group, 22 of 23 patients had 100% of points within the PTV pass {gamma} criteria. The average maximum and mean {gamma} indices were very low (well below 1), indicating good agreement between dose distributions. Increasing the cine duration generally increased the dose agreement. In the follow-up study, 49 of 50 patients had 100% of points within the PTV pass the {gamma} criteria. The average maximum and mean {gamma} indices were again well below 1, indicating good agreement. Dose calculation on RACT from cine CT is negligibly different from dose calculation on RACT from 4D-CT. Differences can be decreased further by increasing the cine duration of the cine CT scan.« less

Microtomography evaluation of dental tissue wear surface induced by in vitro simulated chewing cycles on human and composite teeth.

PubMed

Bedini, Rossella; Pecci, Raffaella; Notarangelo, Gianluca; Zuppante, Francesca; Persico, Salvatore; Di Carlo, Fabio

2012-01-01

In this study a 3D microtomography display of tooth surfaces after in vitro dental wear tests has been obtained. Natural teeth have been compared with prosthetic teeth, manufactured by three different polyceramic composite materials. The prosthetic dental element samples, similar to molars, have been placed in opposition to human teeth extracted by paradontology diseases. After microtomography analysis, samples have been subjected to in vitro fatigue test cycles by servo-hydraulic mechanical testing machine. After the fatigue test, each sample has been subjected again to microtomography analysis to obtain volumetric value changes and dental wear surface images. Wear surface images were obtained by 3D reconstruction software and volumetric value changes were measured by CT analyser software. The aim of this work has been to show the potential of microtomography technique to display very clear and reliable wear surface images. Microtomography analysis methods to evaluate volumetric value changes have been used to quantify dental tissue and composite material wear.

Feasibility of a Single Contrast Bolus High-Pitch Pulmonary CT Angiography Protocol Followed by Low-Dose Retrospectively ECG-Gated Cardiac CT in Patients with Suspected Pulmonary Embolism.

PubMed

Schäfer, Julia Carmen; Haubenreisser, Holger; Meyer, Mathias; Grüttner, Joachim; Walter, Thomas; Borggrefe, Martin; Schoepf, Joseph U; Nance, John W; Schönberg, Stefan O; Henzler, Thomas

2018-06-01

 To prospectively evaluate the feasibility of single contrast bolus high-pitch CT pulmonary angiography (CTPA) subsequently followed by low-dose retrospectively ECG-gated cardiac CT (4D-cCT) in patients with suspected pulmonary embolism (PE) to accurately evaluate right ventricular (RV) function.  62 patients (33 female, age 65.1 ± 17.5 years) underwent high-pitch CTPA examination with 80cc of iodinated contrast material. 5 s after the end of the high-pitch CTPA study, a low-dose retrospectively ECG-gated cardiac CT examination was automatically started. The volume CT dose index (CTDI vol) and dose length product (DLP) were recorded in all patients and the effective dose was calculated. For the assessment of image quality, attenuation was measured as Hounsfield units (HUs) within various regions of interest (ROIs). These ROIs were used to calculate the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Subjective image quality was assessed using a five-point Likert scale. On 4D-cCT, the ejection fraction of both ventricles (RVEF, LVEF) as well as the ratio of RVEF and LVEF (RVEF/LVEF) was assessed. The statistical difference of all parameters between the PE and non-PE group was calculated.  The mean effective radiation dose was 4.22 ± 2.05 mSv. Attenuation measurements on CTPA showed the highest attenuation values in the main pulmonary artery (442.01 ± 187.64). On 4D-cCT attenuation values were highest in the descending aorta (560.59 ± 208.81). The CNR and SNR values on CTPA were highest within the main pulmonary artery (CNR = 12.43 ± 4.57; SNR = 15.14 ± 4.90). On 4D-cCT images, the highest SNR and CNR could be measured in the descending aorta (CNR = 10.26 ± 5.57; SNR = 10.86 ± 5.17). The mean LVEF was 60.73 %± 14.65 %, and the mean RVEF was 44.90 %± 9.54 %. The mean RVEF/LVEF was 0.79 ± 0.29. There was no significant difference between the PE and non-PE group for either of the parameters.  The investigated combined CTPA and 4D-cCT protocol is feasible using a single contrast bolus and allows the evaluation of RV function in patients with suspected PE. Further studies have to evaluate the additional value of this protocol regarding risk stratification in patients with PE.   · High-pitch CTPA is fast enough to leave sufficient contrast material within the heart that can be used for an additional low-dose functional cardiac CT examination.. · The tube current of the evaluated 4D-cCT is reduced over the entire cardiac cycle without any full dose peak.. · Low-dose cardiac CT subsequently performed after high-pitch CTPA allows for detailed analysis of RV function.. · Schäfer JC, Haubenreisser H, Meyer M et al. Feasibility of a Single Contrast Bolus High-Pitch Pulmonary CT Angiography Protocol Followed by Low-Dose Retrospectively ECG-Gated Cardiac CT in Patients with Suspected Pulmonary Embolism. Fortschr Röntgenstr 2018; 190: 542 - 550. © Georg Thieme Verlag KG Stuttgart · New York.

Repeated cycles of 5-fluorouracil chemotherapy impaired anti-tumor functions of cytotoxic T cells in a CT26 tumor-bearing mouse model.

PubMed

Wu, Yanhong; Deng, Zhenling; Wang, Huiru; Ma, Wenbo; Zhou, Chunxia; Zhang, Shuren

2016-09-20

Recently, the immunostimulatory roles of chemotherapeutics have been increasingly revealed, although bone marrow suppression is still a common toxicity of chemotherapy. While the numbers and ratios of different immune subpopulations are analyzed after chemotherapy, changes to immune status after each cycle of treatment are less studied and remain unclear. To determine the tumor-specific immune status and functions after different cycles of chemotherapy, we treated CT26 tumor-bearing mice with one to four cycles of 5-fluorouracil (5-FU). Overall survival was not improved when more than one cycle of 5-FU was administered. Here we present data concerning the immune statuses after one and three cycles of chemotherapy. We analyzed the amount of spleen cells from mice treated with one and three cycles of 5-FU as well as assayed their proliferation and cytotoxicity against the CT26 tumor cell line. We found that the absolute numbers of CD8 T-cells and NK cells were not influenced significantly after either one or three cycles of chemotherapy. However, after three cycles of 5-FU, proliferated CD8 T-cells were decreased, and CT26-specific cytotoxicity and IFN-γ secretion of spleen cells were impaired in vitro. After one cycle of 5-FU, there was a greater percentage of tumor infiltrating CD8 T-cells. In addition, more proliferated CD8 T-cells, enhanced tumor-specific cytotoxicity as well as IFN-γ secretion of spleen cells against CT26 in vitro were observed. Given the increased expression of immunosuppressive factors, such as PD-L1 and TGF-β, we assessed the effect of early introduction of immunotherapy in combination with chemotherapy. We found that mice treated with cytokine induced killer cells and PD-L1 monoclonal antibodies after one cycle of 5-FU had a better anti-tumor performance than those treated with chemotherapy or immunotherapy alone. These data suggest that a single cycle of 5-FU treatment promoted an anti-tumor immune response, whereas repeated chemotherapy cycles impaired anti-tumor immune functions. Though the amount of immune cells could recover after chemotherapy suspension, their anti-tumor functions were damaged by multiple rounds of chemotherapy. These findings also point towards early implementation of immunotherapy to improve the anti-tumor effect.

Light-Induced resetting of the circadian pacemaker: quantitative analysis of transient versus steady-state phase shifts.

PubMed

Watanabe, K; Deboer, T; Meijer, J H

2001-12-01

The suprachiasmatic nuclei of the hypothalamus contain the major circadian pacemaker in mammals, driving circadian rhythms in behavioral and physiological functions. This circadian pacemaker's responsiveness to light allows synchronization to the light-dark cycle. Phase shifting by light often involves several transient cycles in which the behavioral activity rhythm gradually shifts to its steady-state position. In this article, the authors investigate in Syrian hamsters whether a phase-advancing light pulse results in immediate shifts of the PRC at the next circadian cycle. In a first series of experiments, the authors aimed a light pulse at CT 19 to induce a phase advance. It appeared that the steady-state phase advances were highly correlated with activity onset in the first and second transient cycle. This enabled them to make a reliable estimate of the steady-state phase shift induced by a phase-advancing light pulse on the basis of activity onset in the first transient cycle. In the next series of experiments, they presented a light pulse at CT 19, which was followed by a second light pulse aimed at the delay zone of the PRC on the next circadian cycle. The immediate and steady-state phase delays induced by the second light pulse were compared with data from a third experiment in which animals received a phase-delaying light pulse only. The authors observed that the waveform of the phase-delay part of the PRC (CT 12-16) obtained in Experiment 2 was virtually identical to the phase-delay part of the PRC for a single light pulse (obtained in Experiment 3). This finding allowed for a quantitative assessment of the data. The analysis indicates that the delay part of the PRC-between CT 12 and CT 16-is rapidly reset following a light pulse at CT 19. These findings complement earlier findings in the hamster showing that after a light pulse at CT 19, the phase-advancing part of the PRC is immediately shifted. Together, the data indicate that the basis for phase advancing involves rapid resetting of both advance and delay components of the PRC.

Big data driven cycle time parallel prediction for production planning in wafer manufacturing

NASA Astrophysics Data System (ADS)

Wang, Junliang; Yang, Jungang; Zhang, Jie; Wang, Xiaoxi; Zhang, Wenjun Chris

2018-07-01

Cycle time forecasting (CTF) is one of the most crucial issues for production planning to keep high delivery reliability in semiconductor wafer fabrication systems (SWFS). This paper proposes a novel data-intensive cycle time (CT) prediction system with parallel computing to rapidly forecast the CT of wafer lots with large datasets. First, a density peak based radial basis function network (DP-RBFN) is designed to forecast the CT with the diverse and agglomerative CT data. Second, the network learning method based on a clustering technique is proposed to determine the density peak. Third, a parallel computing approach for network training is proposed in order to speed up the training process with large scaled CT data. Finally, an experiment with respect to SWFS is presented, which demonstrates that the proposed CTF system can not only speed up the training process of the model but also outperform the radial basis function network, the back-propagation-network and multivariate regression methodology based CTF methods in terms of the mean absolute deviation and standard deviation.

Surface Roughness of Composite Resins after Simulated Toothbrushing with Different Dentifrices

PubMed Central

Monteiro, Bruna; Spohr, Ana Maria

2015-01-01

Background: The aim of the study was to evaluate, in vitro, the surface roughness of two composite resins submitted to simulated toothbrushing with three different dentifrices. Materials and Methods: Totally, 36 samples of Z350XT and 36 samples of Empress Direct were built and randomly divided into three groups (n = 12) according to the dentifrice used (Oral-B Pro-Health Whitening [OBW], Colgate Sensitive Pro-Relief [CS], Colgate Total Clean Mint 12 [CT12]). The samples were submitted to 5,000, 10,000 or 20,000 cycles of simulated toothbrushing. After each simulated period, the surface roughness of the samples was measured using a roughness tester. Results: According to three-way analysis of variance, dentifrice (P = 0.044) and brushing time (P = 0.000) were significant. The composite resin was not significant (P = 0.381) and the interaction among the factors was not significant (P > 0.05). The mean values of the surface roughness (µm) followed by the same letter represent no statistical difference by Tukey's post-hoc test (P <0.05): Dentifrice: CT12 = 0.269a; CS Pro- Relief = 0.300ab; OBW = 0.390b. Brushing time: Baseline = 0,046ª; 5,000 cycles = 0.297b; 10,000 cycles = 0.354b; 20,000 cycles = 0.584c. Conclusion: Z350 XT and Empress Direct presented similar surface roughness after all cycles of simulated toothbrushing. The higher the brushing time, the higher the surface roughness of composite resins. The dentifrice OBW caused a higher surface roughness in both composite resins. PMID:26229362

Evaluation of a shortened QIAsymphony DNA extraction protocol for stool samples using a multiplex real-time PCR for the detection of enteric pathogens.

PubMed

van Zanten, E; Wisselink, G J; Stoll, S; Alvarez, R; Kooistra-Smid, A M D

2011-02-01

A shortened DNA extraction protocol for the QIAsymphony SP was evaluated by quantitative and qualitative comparison of real-time PCR results of 150 co-extracted stool samples. The average ∆Cycle threshold value for positive pathogenic targets was 0.28 Ct. A consensus of 96.91%, with a correlation coefficient of 0.9880 was recorded. Copyright © 2010 Elsevier B.V. All rights reserved.

Moderate Intensity Cycling Exercise after Upper Extremity Resistance Training Interferes Response to Muscle Hypertrophy but Not Strength Gains

PubMed Central

Tomiya, Shigeto; Kikuchi, Naoki; Nakazato, Koichi

2017-01-01

The purpose of the present study was to examine the effect of 30-min moderate intensity cycling exercise immediately after upper-body resistance training on the muscle hypertrophy and strength gain. Fourteen subjects were randomly divided between two groups. One group performed moderate intensity (55% of maximum oxygen consumption [VO2max], 30 min) cycle training immediately after arm resistance training as concurrent training (CT; n = 7, age: 21.8 ± 0.7 years, height: 1.68 ± 0.06 m, weight: 60.3 ± 7.4 kg); the second group performed the same endurance and arm RT on separate days as control group (SEP; n=7, age: 22.1 ± 0.7 years, height: 1.76 ± 0.05 m, weight: 63.8 ± 3.6 kg). The supervised progressive RT program was designed to induce muscular hypertrophy (3-5 sets of 10 repetitions) with bilateral arm-curl exercise using 75% of the one repetition maximum (1RM) with 2-min rest intervals. The RT program was performed for 8 weeks, twice per week. Muscle cross-sectional area (CSA), 1RM, and VO2max were measured pre- and post-training. Significant increases in muscle CSA from pre- to post-training were observed in both the SEP (p = 0.001, effect size [ES] = 0.84) and the CT groups (p = 0.004, ES = 0.45). A significant increase in 1RM from pre- to post-training was observed in the SEP (p = 0.025, ES = 0.91) and CT groups (p = 0.001, ES = 2.38). There were no interaction effects (time × group) for CSA, 1RM, or VO2max. A significantly higher percentage change of CSA was observed in the SEP group (12.1 ± 4.9%) compared to the CT group (5.0 ± 2.7%, p = 0.029), but no significant difference was observed in the 1RM (SEP: 19.8 ± 16.8%, CT: 24.3 ± 11.1%). The data suggest that significant improvement of CSA and strength can be expected with progressive resistance training with subsequent endurance exercise performed immediately or on a different day. Changes in CSA might be affected by subsequent cycling exercise after 8 weeks of training. Key points Moderate intensity cycling exercise immediately after upper-body resistance training influences the magnitude of muscle hypertrophy and relative value of CSA changes. There was no statistically significant difference in the % change in 1RM between groups after concurrent strength training and moderate intensity endurance training. Timing of endurance training could alter the degree of muscular growth induced by resistance training. PMID:28912657

Value of Ki-67 and computed tomography in the assessment of peripheral lung adenocarcinoma.

PubMed

Chen, Cheng; Zhu, Wei-Dong; Zhang, Xiao-Hui; Zhu, Ye-Han; Huang, Jian-An

2016-01-01

This study was designed to determine whether proliferation antigen Ki-67 and/or a computed tomography (CT) value could be used to evaluate the clinical-pathological features of peripheral lung adenocarcinoma. A total of 116 eligible lung cancer patients were enrolled. Nodule size, lymph node metastasis, differentiation, Ki-67 expression and CT findings were assessed. The relationship between clinic parameters and the CT feature was analysed statistically. The percentage of lesions that had ground-glass opacity or localised air bronchogram was significantly greater in low CT value group (<30, p < 0.05). No significant association was observed between CT value and size in the subgroup with CT value > 0 (p = 0.66). As a proliferative marker of lung cancer, Ki-67 was present in a total of 115 (99.9%) of the 116 evaluable primary lung cancers. There was a statistically significant correlation between the Ki-67 index and CT value (p < 0.05). Compared to CT value, Ki-67 index possessed higher sensitivity to predict the differentiation and lymph node metastasis of peripheral lung adenocarcinoma, adding of CT value would enhance its specificity. Combination of Ki-67 expression and CT value determination was useful for the classification of differentiation and metastatic or proliferative potential of peripheral lung adenocarcinoma.

[A Retrospective Study of Mean Computed Tomography Value to Predict 
the Tumor Invasiveness in AAH and Clinical Stage Ia Lung Cancer].

PubMed

Wu, Hanran; Liu, Changqing; Xu, Meiqing; Xiong, Ran; Xu, Guangwen; Li, Caiwei; Xie, Mingran

2018-03-20

Recently, the detectable rate of ground-glass opacity (GGO ) was significantly increased, a appropriate diagnosis before clinic treatment tends to be important for patients with GGO lesions. The aim of this study is to validate the ability of the mean computed tomography (m-CT) value to predict tumor invasiveness, and compared with other measurements such as Max CT value, GGO size, solid size of GGO and C/T ratio (consolid/tumor ratio, C/T) to find out the best measurement to predict tumor invasiveness. A retrospective study was conducted of 129 patients who recieved lobectomy and were pathological confirmed as atypical adenomatous pyperplasia (AAH) or clinical stage Ia lung cance in our center between January 2012 and December 2013. Of those 129 patients, the number of patients of AAH, AIS, AIS and invasive adenocarcinoma were 43, 26, 17 and 43, respectively. We defined AAH and AIS as noninvasive cancer (NC), MIA and invasive adenocarcinoma were categorized as invasive cancer(IC). We used receiver operating characteristic (ROC) curve analysis to compare the ability to predict tumor invasiveness between m-CT value, consolidation/tumor ratio, tumor size and solid size of tumor. Multiple logistic regression analyses were performed to determine the independent variables for prediction of pathologic more invasive lung cancer. 129 patients were enrolled in our study (59 male and 70 female), the patients were a median age of (62.0±8.6) years (range, 44 to 82 years). The two groups were similar in terms of age, sex, differentiation (P>0.05). ROC curve analysis was performed to determine the appropriate cutoff value and area under the cure (AUC). The cutoff value of solid tumor size, tumor size, C/T ratio, m-CT value and Max CT value were 9.4 mm, 15.3 mm, 47.5%, -469.0 HU and -35.0 HU, respectively. The AUC of those variate were 0.89, 0.79, 0.82, 0.90, 0.85, respectively. When compared the clinical and radiologic data between two groups, we found the IC group was strongly associated with a high m-CT value, high Max CT value, high C/T ratio and large tumor size. Gender, solid tumor size, tumor size, C/T ratio, m-CT value and MaxCT value were selected factor for multivariate analysis, when using the preoperatively determined variables to predict the tumor invasiveness, revealed that tumor size, C/T ratio, m-CT value and Max CT value were independent predictive factors of IC. The musurements of Max CT value, GGO size, solid size of GGO and C/T ratio were significantly correlated with tumor invasiveness, and the evaluation of m-CT value is most useful musurement in predicting more invasive lung cancer.

Development and Evaluation of Methods for Structured Recording of Heart Murmur Findings Using SNOMED-CT® Post-Coordination

PubMed Central

Green, Julie M.; Wilcke, Jeffrey R.; Abbott, Jonathon; Rees, Loren P.

2006-01-01

Objective: This study evaluated an existing SNOMED-CT® model for structured recording of heart murmur findings and compared it to a concept-dependent attributes model using content from SNOMED-CT. Methods: The authors developed a model for recording heart murmur findings as an alternative to SNOMED-CT's use of Interprets and Has interpretation. A micro-nomenclature was then created to support each model using subset and extension mechanisms described for SNOMED-CT. Each micro-nomenclature included a partonomy of cardiac cycle timing values. A mechanism for handling ranges of values was also devised. One hundred clinical heart murmurs were recorded using purpose-built recording software based on both models. Results: Each micro-nomenclature was extended through the addition of the same list of concepts. SNOMED role grouping was required in both models. All 100 clinical murmurs were described using each model. The only major differences between the two models were the number of relationship rows required for storage and the hierarchical assignments of concepts within the micro-nomenclatures. Conclusion: The authors were able to capture 100 clinical heart murmurs with both models. Requirements for implementing the two models were virtually identical. In fact, data stored using these models could be easily interconverted. There is no apparent penalty for implementing either approach. PMID:16501179

A First Look at Oxygen and Silicon Isotope Variations in Diatom Silica from a Pliocene Antarctic Marine Sediment Core

NASA Astrophysics Data System (ADS)

Abbott, T.; Dodd, J. P.; Hackett, H.; Scherer, R. P.

2016-02-01

Coupled oxygen (δ18O) and silicon (δ30Si) isotope variations in diatom silica (opal-A) are increasingly used as a proxy to reconstruct paleoenvironmental conditions (water temperatures, water mass mixing, nutrient cycling) in marine environments. Diatom silica is a particularly significant paleoenvironmental proxy in high latitude environments, such as the Southern Ocean, where diatom blooms are abundant and diatom frustules are well preserved in the sediment. The Andrill-1B (AND-1B) sediment core from the Ross Sea (Antarctica) preserves several Pliocene ( 4.5 Ma) age diatomite units. Here we present preliminary δ18O and δ30Si values for a diatomite subunit in the AND-1B sediment core. Initial isotope values for the AND-1B diatoms silica record relatively high variability (range δ18O: 36.3‰ to 39.9‰) that could be interpreted as large-scale changes in the water temperature and/or freshwater mixing in the Ross Sea; however, a significant concern with marine sediment of this age is isotope fractionation during diagenesis and the potential formation of opal-CT lepispheres. The effects of clay contamination on the diatom silica δ18O values have been addressed through sample purification and quantified through chemical and physical analyses of the diatom silica. The isotopic effects of opal-CT are not as clearly understood and more difficult to physically separate from the primary diatom silica. In order to better understand the isotope variations in the AND-1B diatoms, we also evaluated silicon and oxygen isotope fractionation during the transition from opal-A to opal-CT in a controlled laboratory experiment. Opal-A from cultured marine diatoms (Thalassiosira weissflogii) was subjected to elevated temperatures (150°C) in acid digestion vessels for 4 weeks to initiate opal-CT precipitation. Quantifying the effects of opal-CT formation on δ18O and δ30Si variations in biogenic silica improves our understanding of the use of diatom silica isotope values a paleoenvironmental proxy throughout the Cenozoic.

Impact of removable partial denture prosthesis on chewing efficiency

PubMed Central

BESSADET, Marion; NICOLAS, Emmanuel; SOCHAT, Marine; HENNEQUIN, Martine; VEYRUNE, Jean-Luc

2013-01-01

Removable partial denture prostheses are still being used for anatomic, medical and economic reasons. However, the impact on chewing parameters is poorly described. Objectives The objective of this study was to estimate the impact of removable partial denture prosthesis on masticatory parameters. Material and Methods Nineteen removable partial denture prosthesis (RPDP) wearers participated in the study. Among them, 10 subjects were Kennedy Class III partially edentulous and 9 with posterior edentulism (Class I). All presented a complete and full dentate opposing arch. The subjects chewed samples of carrots and peanuts with and without their prosthesis. The granulometry of the expectorated boluses from carrot and peanuts was characterized by median particle size (D50), determined at the natural point of swallowing. Number of chewing cycles (CC), chewing time (CT) and chewing frequency (CF=CC/CT) were video recorded. Results With RPDP, the mean D50 values for carrot and peanuts were lower [Repeated Model Procedures (RMP), F=15, p<0.001] regardless of the type of Kennedy Class. For each food, mean CC, CT and CF values recorded decreased (RMP, F=18, F=9, and F=20 respectively, p<0.01). With or without RPD, the boluses' granulometry values were above the masticatory normative index (MNI) determined as 4,000 µm. Conclusion RPDP rehabilitation improves the ability to reduce the bolus particle size, but does not reestablish fully the masticatory function. Clinical relevance This study encourages the clinical improvement of oral rehabilitation procedure. PMID:24212983

[Analysis of the frequencies of genotype combinations of 4 polymorphisms of genes acting on the folate cycle in the Spanish population].

PubMed

Martínez-Frías, María Luisa; Bermejo, Eva; Pérez, Belén; Desviat, Lourdes R; Castro, Margarita; Leal, Fátima; Mansilla, Elena; Martínez-Fernández, María Luisa; Rodríguez-Pinilla, Elvira; Rodríguez, Laura; Ugarte, Magdalena

2008-06-21

Studies on different populations have shown a great variability of the frequencies of different polymorphisms in genes acting in the folate cycle. The present study was aimed to analyze the frequency in the Spanish population of each genotype combination of four polymorphisms, one of them -1561C-T of the glutamate carboxypeptidase II (GCPII) gene- being the first time that is studied in Spain. The study included a meta-analysis of the published data. Using the Spanish Collaborative Study of Congenital Malformations (ECEMC) Network, blood samples of 190 mother-child couples with newborns without any congenital defect, were obtained from 15 Spanish autonomous regions. The study polymorphisms were the 677C-T and 1298A-C polymorphisms of the methylenetetrahydrofolate reductase (MTHFR), the 66A-G of the methionine synthase reductase (MTRR), and the 1561C-T polymorphism of the GCPII gene. To estimate the range for the population frequencies, 99% confidence intervals were calculated. The frequencies observed in our country were significantly different from others, being similar to those obtained in countries of the Mediterranean European area. The 1561C-T polymorphism of the GCPII gene has a frequency in Spain of 5.11%, which is also similar to the values observed in France (5%) and in Italy (6%). On the other hand, the frequency of the genotypes CTCC, TTAC is quite few, while the genotype TTCC was not observed in any mother or infants. A meta-analysis was performed for a big sample (23,612 individuals) and the results showed that with a 99% of probability the values for the genotype combinations CTCC, TTAC, and TTCC were within 0.10-0.24; 0.20-0.36; and 0.003-0.05, respectively. Our results are important to further analyze the relationship with some health problems and individual susceptibilities. Indeed, considering the published observations of the structure and function of the MTHFR enzyme, it is understandable that those genotype combinations that are quite little frequent, may be related to the embryo-fetal viability, and to the life style of each population.

Calcitonin assay in wash-out fluid after fine-needle aspiration biopsy in patients with a thyroid nodule and border-line value of the hormone.

PubMed

Massaro, F; Dolcino, M; Degrandi, R; Ferone, D; Mussap, M; Minuto, F; Giusti, M

2009-04-01

Assaying calcitonin (CT) in the wash-out fluid from fine-needle aspiration biopsies (CT-FNAB) could be useful in the diagnosis of medullary thyroid carcinoma (MTC). The aim of this study was to correlate serum CT with cytology and CT-FNAB. Twenty-seven subjects (age range 27-75 yr) were studied. FNAB was performed in a thyroid nodule (no.=16) or lymph-node (no.=1 previously operated on for MTC) or in the prevalent nodule of multinodular goiters (no.=10). CT-FNAB values obtained in 37 subjects with normal serum CT (<10 ng/l) who underwent FNAB for thyroid nodules served as a negative control. In these subjects, CTFNAB values were 8.2+/-6.4 ng/l (range 2-30 ng/l). In patients with a thyroid nodule under evaluation for MTC, serum CT and CT-FNAB values were 14.5+/-3.9 ng/l (range 10-24 ng/l) and 16.4+/-29.8 ng/l (range 2-144 ng/l), respectively. In 4 patients, CT-FNAB values were higher than the highest values found in our negative controls (30 ng/l), but cytology results were compatible with a benign thyroid lesion and pentagastrin testing was negative. In 3 cases with CT-FNAB <30 ng/l, cytology was indicative of an indeterminate or probably follicular malignant lesion and histology was negative for MTC. None of the other subjects in whom pentagastrin testing was conducted showed serum CT values >100 ng/l. Our data do not show any correlation between CT-FNAB and serum CT. In conclusion, borderline CT values in patients with thyroid nodules are not rare. Our experience suggests that CT-FNAB does not have the same importance as that reported in the literature for thyroglobulin and PTH assay in wash-out fluid after FNAB in malignant thyroid and hyperfunctioning parathyroid lesions.

EFFECT ON PERFUSION VALUES OF SAMPLING INTERVAL OF CT PERFUSION ACQUISITIONS IN NEUROENDOCRINE LIVER METASTASES AND NORMAL LIVER

PubMed Central

Ng, Chaan S.; Hobbs, Brian P.; Wei, Wei; Anderson, Ella F.; Herron, Delise H.; Yao, James C.; Chandler, Adam G.

2014-01-01

Objective To assess the effects of sampling interval (SI) of CT perfusion acquisitions on CT perfusion values in normal liver and liver metastases from neuroendocrine tumors. Methods CT perfusion in 16 patients with neuroendocrine liver metastases were analyzed by distributed parameter modeling to yield tissue blood flow, blood volume, mean transit time, permeability, and hepatic arterial fraction, for tumor and normal liver. CT perfusion values for the reference sampling interval of 0.5s (SI0.5) were compared with those of SI datasets of 1s, 2s, 3s and 4s, using mixed-effects model analyses. Results Increases in SI beyond 1s were associated with significant and increasing departures of CT perfusion parameters from reference values at SI0.5 (p≤0.0009). CT perfusion values deviated from reference with increasing uncertainty with increasing SIs. Findings for normal liver were concordant. Conclusion Increasing SIs beyond 1s yield significantly different CT perfusion parameter values compared to reference values at SI0.5. PMID:25626401

High-Frequency Jet Ventilation for Complete Target Immobilization and Reduction of Planning Target Volume in Stereotactic High Single-Dose Irradiation of Stage I Non-Small Cell Lung Cancer and Lung Metastases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fritz, Peter, E-mail: p.h.fritz@t-online.d; Kraus, Hans-Joerg; Muehlnickel, Werner

2010-09-01

Purpose: To demonstrate the feasibility of complete target immobilization by means of high-frequency jet ventilation (HFJV); and to show that the saving of planning target volume (PTV) on the stereotactic body radiation therapy (SBRT) under HFJV, compared with SBRT with respiratory motion, can be predicted with reliable accuracy by computed tomography (CT) scans at peak inspiration phase. Methods and Materials: A comparison regarding different methods for defining the PTV was carried out in 22 patients with tumors that clearly moved with respiration. A movement span of the gross tumor volume (GTV) was defined by fusing respiration-correlated CT scans. The PTVmore » enclosed the GTV positions with a safety margin throughout the breathing cycle. To create a PTV from CT scans acquired under HFJV, the same margins were drawn around the immobilized target. In addition, peak inspiration phase CT images (PIP-CTs) were used to approximate a target immobilized by HFJV. Results: The resulting HFJV-PTVs were between 11.6% and 45.4% smaller than the baseline values calculated as respiration-correlated CT-PTVs (median volume reduction, 25.4%). Tentative planning by means of PIP-CT PTVs predicted that in 19 of 22 patients, use of HFJV would lead to a reduction in volume of {>=}20%. Using this threshold yielded a positive predictive value of 0.89, as well as a sensitivity of 0.94 and a specificity of 0.5. Conclusions: In all patients, SBRT under HFJV provided a reliable immobilization of the GTVs and achieved a reduction in PTVs, regardless of patient compliance. Tentative planning facilitated the selection of patients who could better undergo radiation in respiratory standstill, both with greater accuracy and lung protection.« less

Smad4 sensitizes colorectal cancer to 5-fluorouracil through cell cycle arrest by inhibiting the PI3K/Akt/CDC2/survivin cascade.

PubMed

Zhang, Binhao; Leng, Chao; Wu, Chao; Zhang, Zhanguo; Dou, Lei; Luo, Xin; Zhang, Bixiang; Chen, Xiaoping

2016-03-01

5-Fluorouracil (5-FU), a cell cycle-specific antimetabolite, is one of the most commonly used chemotherapeutic agents for colorectal cancer (CRC). Yet, resistance to 5-FU-based chemotherapy is still an obstacle to the treatment of this malignancy. Mutation or loss of Smad4 in CRC is pivotal for chemoresistance. However, the mechanism by which Smad4 regulates the chemosensitivity of CRC remains unclear. In the present study, we investigated the role of Smad4 in the chemosensitivity of CRC to 5-FU, and whether Smad4-regulated cell cycle arrest is involved in 5-FU chemoresistance. We used Smad4-expressing CT26 and Smad4-null SW620 cell lines as experimental models, by knockdown or transgenic overexpression. Cells or tumors were treated with 5-FU to determine chemosensitivity by cell growth, tumorigenicity assay and a mouse model. Cell cycle distribution was examined with flow cytometric analysis, and cell cycle-related proteins were examined by western blotting. Smad4 deficiency in CT26 and SW620 cells induced chemoresistance to 5-FU both in vitro and in vivo. Smad4 deficiency attenuated G1 or G2 cell cycle arrest by activating the PI3K/Akt/CDC2/survivin pathway. The PI3K inhibitor, LY294002, reversed the activation of the Akt/CDC2/survivin cascade in the Smad4-deficient cells, while it had little effect on cells with high Smad4 expression. In conclusion, we discovered a novel mechanism mediated by Smad4 to trigger 5-FU chemosensitivity through cell cycle arrest by inhibiting the PI3K/Akt/CDC2/survivin cascade. The present study also implies that LY294002 has potential therapeutic value to reverse the chemosensitivity of CRC with low Smad4 expression.

Structured physician order entry for trauma CT: value in improving clinical information transfer and billing efficiency.

PubMed

Wortman, Jeremy R; Goud, Asha; Raja, Ali S; Marchello, Dana; Sodickson, Aaron

2014-12-01

The purpose of this study was to measure the effects of use of a structured physician order entry system for trauma CT on the communication of clinical information and on coding practices and reimbursement efficiency. This study was conducted between April 1, 2011, and January 14, 2013, at a level I trauma center with 59,000 annual emergency department visits. On March 29, 2012, a structured order entry system was implemented for head through pelvis trauma CT, so-called pan-scan CT. This study compared the following factors before and after implementation: communication of clinical signs and symptoms and mechanism of injury, primary International Classification of Diseases, 9th revision, Clinical Modification (ICD-9-CM) code category, success of reimbursement, and time required for successful reimbursement for the examination. Chi-square statistics were used to compare all categoric variables before and after the intervention, and the Wilcoxon rank sum test was used to compare billing cycle times. A total of 457 patients underwent pan-scan CT in 2734 distinct examinations. After the intervention, there was a 62% absolute increase in requisitions containing clinical signs or symptoms (from 0.4% to 63%, p<0.0001) and a 99% absolute increase in requisitions providing mechanism of injury (from 0.4% to 99%, p<0.0001). There was a 19% absolute increase in primary ICD-9-CM codes representing clinical signs or symptoms (from 2.9% to 21.8%, p<0.0001), and a 7% absolute increase in reimbursement success for examinations submitted to insurance carriers (from 83.0% to 89.7%, p<0.0001). For reimbursed studies, there was a 14.7-day reduction in mean billing cycle time (from 68.4 days to 53.7 days, p=0.008). Implementation of structured physician order entry for trauma CT was associated with significant improvement in the communication of clinical history to radiologists. The improvement was also associated with changes in coding practices, greater billing efficiency, and an increase in reimbursement success.

Determination of CT number and density profile of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using computed tomography imaging and electron density phantom

NASA Astrophysics Data System (ADS)

Yusof, Mohd Fahmi Mohd; Hamid, Puteri Nor Khatijah Abdul; Bauk, Sabar; Hashim, Rokiah; Tajuddin, Abdul Aziz

2015-04-01

Plug density phantoms were constructed in accordance to CT density phantom model 062M CIRS using binderless, pre-treated and tannin-based Rhizophora Spp. particleboards. The Rhizophora Spp. plug phantoms were scanned along with the CT density phantom using Siemens Somatom Definition AS CT scanner at three CT energies of 80, 120 and 140 kVp. 15 slices of images with 1.0 mm thickness each were taken from the central axis of CT density phantom for CT number and CT density profile analysis. The values were compared to water substitute plug phantom from the CT density phantom. The tannin-based Rhizophora Spp. gave the nearest value of CT number to water substitute at 80 and 120 kVp CT energies with χ2 value of 0.011 and 0.014 respectively while the binderless Rhizphora Spp. gave the nearest CT number to water substitute at 140 kVp CT energy with χ2 value of 0.023. The tannin-based Rhizophora Spp. gave the nearest CT density profile to water substitute at all CT energies. This study indicated the suitability of Rhizophora Spp. particleboard as phantom material for the use in CT imaging studies.

New prospective 4D-CT for mitigating the effects of irregular respiratory motion

NASA Astrophysics Data System (ADS)

Pan, Tinsu; Martin, Rachael M.; Luo, Dershan

2017-08-01

Artifact caused by irregular respiration is a major source of error in 4D-CT imaging. We propose a new prospective 4D-CT to mitigate this source of error without new hardware, software or off-line data-processing on the GE CT scanner. We utilize the cine CT scan in the design of the new prospective 4D-CT. The cine CT scan at each position can be stopped by the operator when an irregular respiration occurs, and resumed when the respiration becomes regular. This process can be repeated at one or multiple scan positions. After the scan, a retrospective reconstruction is initiated on the CT console to reconstruct only the images corresponding to the regular respiratory cycles. The end result is a 4D-CT free of irregular respiration. To prove feasibility, we conducted a phantom and six patient studies. The artifacts associated with the irregular respiratory cycles could be removed from both the phantom and patient studies. A new prospective 4D-CT scanning and processing technique to mitigate the impact of irregular respiration in 4D-CT has been demonstrated. This technique can save radiation dose because the repeat scans are only at the scan positions where an irregular respiration occurs. Current practice is to repeat the scans at all positions. There is no cost to apply this technique because it is applicable on the GE CT scanner without new hardware, software or off-line data-processing.

18F-FDG PET/CT in Detecting Metastatic Infection in Children.

PubMed

Kouijzer, Ilse J E; Blokhuis, Gijsbert J; Draaisma, Jos M T; Oyen, Wim J G; de Geus-Oei, Lioe-Fee; Bleeker-Rovers, Chantal P

2016-04-01

Metastatic infection is a severe complication of bacteremia with high morbidity and mortality. The aim of this study was to investigate the diagnostic value of 18F-FDG PET combined with CT (FDG PET/CT) in children suspected of having metastatic infection. The results of FDG PET/CT scans performed in children because of suspected metastatic infection from September 2003 to June 2013 were analyzed retrospectively. The results were compared with the final clinical diagnosis. FDG PET/CT was performed in 13 children with suspected metastatic infection. Of the total number of FDG PET/CT scans, 38% were clinically helpful. Positive predictive value of FDG PET/CT was 71%, and negative predictive value was 100%. FDG PET/CT appears to be a valuable diagnostic technique in children with suspected metastatic infection. Prospective studies of FDG PET/CT as part of a structured diagnostic protocol are needed to assess the exact additional diagnostic value.

Ultimobranchial gland respond in a different way in male and female fresh water teleost Mastacembelus armatus (Lacepede) during reproductive cycle.

PubMed

Verma, Sushant Kumar; Alim, Abdul

2015-05-01

The present study was carried out to analyze the differences in the activity of ultimobranchial gland (UBG) between male and female fresh water teleost Mastacembelus armatus during reproductive cycle. Considerable variations in the nuclear diameter of UBG cells and plasma calcitonin (CT) levels during different reproductive phases of testicular and ovarian cycle suggested that the activity of the UBG depends upon the sexual maturity of fishes. A positive correlation was observed between plasma CT and sex steroid levels and the gonadosomatic index in both sexes which further confirmed the involvement of UBG in the processes related to gonadal development in fishes irrespective of the sex. Sudden increase in the level of plasma CT and nuclear diameter of UBG cells after administration of 17 α-methyltestosterone in males and 17 β-estradiol in females during resting phase of the reproductive cycle clearly showed that UBG becomes hyperactive with increases in the level of sex steroids. Plasma calcium level was also found to be positively correlated with gonadal maturation in females. However no such change in plasma calcium level in relation to testicular cycle was observed. Thus it can be concluded that UBG becomes hyperactive during gonadal maturation but its role differs between male and female fishes. In females it may involved in both gonadal maturation and plasma calcium regulation while in males its involvement in calcium regulation was not justified. Variations in the level of CT during various phases of testicular cycle evidenced its involvement in gonadal maturation only. Copyright © 2015 Elsevier B.V. All rights reserved.

Adrenocortical tumours: high CT attenuation value correlates with eosinophilia but does not discriminate lipid-poor adenomas from malignancy.

PubMed

Pennanen, Mirkka; Raade, Merja; Louhimo, Johanna; Sane, Timo; Heiskanen, Ilkka; Arola, Johanna; Haglund, Caj

2013-12-01

Characterisation of adrenal tumours is an important clinical problem. Unenhanced CT is the primary imaging modality to assess the nature of these lesions. To study the correlation between unenhanced CT attenuation value and the specific histopathology, as well as the proportion of lipid-poor eosinophilic cells in adrenocortical tumours. We studied retrospectively primary adrenocortical tumours that had been operated on at Helsinki University Central Hospital between 2002 and 2008. Of 171 tumours, 79 had appropriate preoperative CT scans and were included in the study. We evaluated the unenhanced CT attenuation values (Hounsfield units, HU) of these tumours and determined their histopathological diagnosis by the Weiss scoring system. We also assessed the proportion of lipid-poor eosinophilic cells for each tumour. Unenhanced CT attenuation value (HU) in adrenocortical tumours correlated well with the proportion of lipid-poor eosinophilic cells (rs=0.750, p<0.001). HU and Weiss score also had a correlation (rs=0.582, p<0.001). Unenhanced CT attenuation value correlates well with the percentage of lipid-poor eosinophilic cells, but unenhanced CT attenuation value fails to differentiate between benign lipid-poor adenomas and malignant adrenocortical tumours. All adrenocortical tumours with unenhanced CT attenuation value ≤10 HU are histologically benign lipid-rich tumours.

Driving CT developments the last mile: case examples of successful and somewhat less successful translations into clinical practice

NASA Astrophysics Data System (ADS)

Sodickson, Aaron D.

2017-03-01

CT technology has advanced rapidly in recent years, yet not all innovations translate readily into clinical practice. Technology advances must meet certain key requirements to make it into routine use: They must provide a well-defined clinical benefit. They must be easy to use and integrate readily into existing workflows, or better still, further streamline these workflows. These requirements heavily favor fully integrated or automated solutions that remove the human factor and provide a reproducible output independent of operator skill level. Further, to achieve these aims, collaboration with the ultimate end users is needed as early as possible in the development cycle, not just at the point of product testing. Technology innovators are encouraged to engage such collaborators even at early stages of feature or product definition. This manuscript highlights these concepts through exploration of challenging areas in CT imaging in an Emergency Department setting. Technique optimization for pulmonary embolus CT is described as an example of successful integration of multiple advances in radiation dose reduction and imaging speed. The typical workflow of a trauma "pan-scan" (incorporating scans from head through pelvis) is described to highlight workflow challenges and opportunities for improvement. Finally, Dual Energy CT is discussed to highlight the undeniable clinical value of the material characterization it provides, yet also its surprisingly slow integration into routine use beyond early adopters.

Results of a pilot study using self-collected mid-turbinate nasal swabs for detection of influenza virus infection among pregnant women.

PubMed

Thompson, Mark G; Ferber, Jeannette R; Odouli, Roxana; David, Donna; Shifflett, Pat; Meece, Jennifer K; Naleway, Allison L; Bozeman, Sam; Spencer, Sarah M; Fry, Alicia M; Li, De-Kun

2015-05-01

We evaluated the feasibility of asking pregnant women to self-collect and ship respiratory specimens. In a preliminary laboratory study, we compared the RT-PCR cycle threshold (CT) values of influenza A and B viruses incubated at 4 storage temperatures (from 4 to 35°C) for 6 time periods (8, 24, 48, 72, and 168 hours and 30 days), resulting in 24 conditions that were compared to an aliquot tested after standard freezing (-20°C) (baseline condition). In a subsequent pilot study, during January-February, 2014, we delivered respiratory specimen collection kits to 53 pregnant women with a medically attended acute respiratory illness using three delivery methods. CT values were stable after storage at temperatures <27°C for up to 72 hours for influenza A viruses and 48 hours for influenza B viruses. Of 53 women who received kits during the pilot, 89% collected and shipped nasal swabs as requested. However, 30% (14/47) of the women took over 2 days to collect and ship their specimen. The human control gene, ribonuclease P (RNase P), was detected in 100% of nasal swab specimens. However, the mean CT values for RNase P (26.5, 95% confidence interval [CI] = 26.0-27.1) and for the 8 influenza A virus positives in our pilot (32.2, 95% CI = 28.9-35.5) were significantly higher than the CTs observed in our 2010-2012 study using staff-collected nasal pharyngeal swabs (P-values < 0.01). Self-collection of respiratory specimens is a promising research method, but further research is needed to quantify the sensitivity and specificity of the approach. © 2015 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

Molecular Mechanism for Prostate Cancer Resistance to the Anti-tumor Activity of Vitamin D

DTIC Science & Technology

2006-11-01

point where each curve crossed the threshold line (Ct) using the following equation : Rel. value = 2[Ct(control) Ct(test)]test gene / 2[Ct(control...by hypermethylation in human pancreatic cancer. J Hum Genet 2005;50:159–67. 41. Armes JE, Hammet F, de Silva M, et al. Candidate tumor-suppressor...line (Ct) using the equation : Rel. Value = 2 - [Ct(control) – Ct(test)]test gene/ 2 -[Ct(control) – Ct(test)]housekeeping gene [22]. Reactions were

CRYPTOSPORIDIUM LOG-INACTIVATION WITH OZONE USING EFFLUENT CT 10, GEOMETRIC MEAN CT 10 EXTENDED INTEGRATED CT 10 AND EXTENDED-CSTR CALCULATIONS

EPA Science Inventory

The draft Long Term 2 Enhanced Surface Water Treatment Rule ("LT2ESWTR") contains Cryptosporidium log-inactivation CT tables. Depending on the water temperature, the Cryptosporidium CT values that are listed are 15 to 25 times greater than CT values fo...

Microstructure Evolution from X-CT Measurements for Concrete/mortar under Multi-actions of Composite Salts Dry-wet Cycles and Loading

NASA Astrophysics Data System (ADS)

Chen, Yanjuan; Gao, Jianming; Shen, Daman

2017-08-01

Inthis research, microstructure evolution forconcrete/mortar under multi-actions of composite salts dry-wet cycles and loading was investigated through X-CT measurements. The evolution process of pores and micro-cracking with the erosion time were tracked. Compared the different erosion actions, it was found that dry-wet cycles promoted the pores become connected gradually. Besides, the dry-wet cycles accelerated the damage seriously on interface area between concrete and aggregate, whistle, loading contributes to the cracking propagation toward the internal. Moreover, fly ash played a positive role in the increasing of the number of harmless holes again and contributed to the durability of concrete.

Assessment of BoneTtissue Mineralization by Conventional X-ray Microcomputed tomography: Comparison with Synchrotron Radiation Microcomputed Tomography and Ash Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kazakia,G.; Burghardt, A.; Cheung, S.

2008-01-01

Assessment of bone tissue mineral density (TMD) may provide information critical to the understanding of mineralization processes and bone biomechanics. High-resolution three-dimensional assessment of TMD has recently been demonstrated using synchrotron radiation microcomputed tomography (SR{mu}CT); however, this imaging modality is relatively inaccessible due to the scarcity of SR facilities. Conventional desktop {mu}CT systems are widely available and have been used extensively to assess bone microarchitecture. However, the polychromatic source and cone-shaped beam geometry complicate assessment of TMD by conventional {mu}CT. The goal of this study was to evaluate {mu}CT-based measurement of degree and distribution of tissue mineralization in a quantitative,more » spatially resolved manner. Specifically, {mu}CT measures of bone mineral content (BMC) and TMD were compared to those obtained by SR{mu}CT and gravimetric methods. Cylinders of trabecular bone were machined from human femoral heads (n=5), vertebrae (n=5), and proximal tibiae (n=4). Cylinders were imaged in saline on a polychromatic {mu}CT system at an isotropic voxel size of 8 {mu}m. Volumes were reconstructed using beam hardening correction algorithms based on hydroxyapatite (HA)-resin wedge phantoms of 200 and 1200 mgHA/cm3. SR{mu}CT imaging was performed at an isotropic voxel size of 7.50 {mu}m at the National Synchrotron Light Source. Attenuation values were converted to HA concentration using a linear regression derived by imaging a calibration phantom. Architecture and mineralization parameters were calculated from the image data. Specimens were processed using gravimetric methods to determine ash mass and density. {mu}CT-based BMC values were not affected by altering the beam hardening correction. Volume-averaged TMD values calculated by the two corrections were significantly different (p=0.008) in high volume fraction specimens only, with the 1200 mgHA/cm3 correction resulting in a 4.7% higher TMD value. {mu}CT and SR{mu}CT provided significantly different measurements of both BMC and TMD (p<0.05). In high volume fraction specimens, {mu}CT with 1200 mgHA/cm3 correction resulted in BMC and TMD values 16.7% and 15.0% lower, respectively, than SR{mu}CT values. In low volume fraction specimens, {mu}CT with 1200 mgHA/cm3 correction resulted in BMC and TMD values 12.8% and 12.9% lower, respectively, than SR{mu}CT values. {mu}CT and SR{mu}CT values were well-correlated when volume fraction groups were considered individually (BMC R2=0.97-1.00; TMD R2=0.78-0.99). Ash mass and density were higher than the SR{mu}CT equivalents by 8.6% in high volume fraction specimens and 10.9% in low volume fraction specimens (p<0.05). BMC values calculated by tomography were highly correlated with ash mass (ash versus {mu}CT R2=0.96-1.00; ash versus SR{mu}CT R2=0.99-1.00). TMD values calculated by tomography were moderately correlated with ash density (ash versus {mu}CT R2=0.64-0.72; ash versus SR{mu}CT R2=0.64). Spatially resolved comparisons highlighted substantial geometric nonuniformity in the {mu}CT data, which were reduced (but not eliminated) using the 1200 mg HA/cm3 beam hardening correction, and did not exist in the SR{mu}CT data. This study represents the first quantitative comparison of {mu}CT mineralization evaluation against SR{mu}CT and gravimetry. Our results indicate that {mu}CT mineralization measures are underestimated but well-correlated with SR{mu}CT and gravimetric data, particularly when volume fraction groups are considered individually.« less

Assessment of bone tissue mineralization by conventional x-ray microcomputed tomography: Comparison with synchrotron radiation microcomputed tomography and ash measurements

PubMed Central

Kazakia, G. J.; Burghardt, A. J.; Cheung, S.; Majumdar, S.

2008-01-01

Assessment of bone tissue mineral density (TMD) may provide information critical to the understanding of mineralization processes and bone biomechanics. High-resolution three-dimensional assessment of TMD has recently been demonstrated using synchrotron radiation microcomputed tomography (SRμCT); however, this imaging modality is relatively inaccessible due to the scarcity of SR facilities. Conventional desktop μCT systems are widely available and have been used extensively to assess bone microarchitecture. However, the polychromatic source and cone-shaped beam geometry complicate assessment of TMD by conventional μCT. The goal of this study was to evaluate μCT-based measurement of degree and distribution of tissue mineralization in a quantitative, spatially resolved manner. Specifically, μCT measures of bone mineral content (BMC) and TMD were compared to those obtained by SRμCT and gravimetric methods. Cylinders of trabecular bone were machined from human femoral heads (n=5), vertebrae (n=5), and proximal tibiae (n=4). Cylinders were imaged in saline on a polychromatic μCT system at an isotropic voxel size of 8 μm. Volumes were reconstructed using beam hardening correction algorithms based on hydroxyapatite (HA)-resin wedge phantoms of 200 and 1200 mg HA∕cm3. SRμCT imaging was performed at an isotropic voxel size of 7.50 μm at the National Synchrotron Light Source. Attenuation values were converted to HA concentration using a linear regression derived by imaging a calibration phantom. Architecture and mineralization parameters were calculated from the image data. Specimens were processed using gravimetric methods to determine ash mass and density. μCT-based BMC values were not affected by altering the beam hardening correction. Volume-averaged TMD values calculated by the two corrections were significantly different (p=0.008) in high volume fraction specimens only, with the 1200 mg HA∕cm3 correction resulting in a 4.7% higher TMD value. μCT and SRμCT provided significantly different measurements of both BMC and TMD (p<0.05). In high volume fraction specimens, μCT with 1200 mg HA∕cm3 correction resulted in BMC and TMD values 16.7% and 15.0% lower, respectively, than SRμCT values. In low volume fraction specimens, μCT with 1200 mg HA∕cm3 correction resulted in BMC and TMD values 12.8% and 12.9% lower, respectively, than SRμCT values. μCT and SRμCT values were well-correlated when volume fraction groups were considered individually (BMC R2=0.97−1.00; TMD R2=0.78−0.99). Ash mass and density were higher than the SRμCT equivalents by 8.6% in high volume fraction specimens and 10.9% in low volume fraction specimens (p<0.05). BMC values calculated by tomography were highly correlated with ash mass (ash versus μCT R2=0.96−1.00; ash versus SRμCT R2=0.99−1.00). TMD values calculated by tomography were moderately correlated with ash density (ash versus μCT R2=0.64−0.72; ash versus SRμCT R2=0.64). Spatially resolved comparisons highlighted substantial geometric nonuniformity in the μCT data, which were reduced (but not eliminated) using the 1200 mg HA∕cm3 beam hardening correction, and did not exist in the SRμCT data. This study represents the first quantitative comparison of μCT mineralization evaluation against SRμCT and gravimetry. Our results indicate that μCT mineralization measures are underestimated but well-correlated with SRμCT and gravimetric data, particularly when volume fraction groups are considered individually. PMID:18697542

Performance of 177Lu-DOTATATE-based peptide receptor radionuclide therapy in metastatic gastroenteropancreatic neuroendocrine tumor: a multiparametric response evaluation correlating with primary tumor site, tumor proliferation index, and dual tracer imaging characteristics.

PubMed

Thapa, Pradeep; Ranade, Rohit; Ostwal, Vikas; Shrikhande, Shailesh V; Goel, Mahesh; Basu, Sandip

2016-10-01

To assess the performance of Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) in metastatic gastroenteropancreatic neuroendocrine tumor (GEP-NET) and correlate it with primary tumor site, tumor proliferation index, and dual tracer imaging characteristics. Fifty patients (M : F 33 : 17, age: 26-71 years) with histopathologically confirmed metastatic/inoperable NETs who had undergone at least three cycles of PRRT with Lu-DOTATATE were included in the analysis. As part of the pretreatment evaluation, they underwent either Tc-HYNIC TOC (n=40)/Ga-DOTATATE PET (n=10) or fluorine-18-fluorodeoxyglucose (F-FDG) PET-computed tomography (CT). Response was assessed after three and five cycles PRRT on the basis of three parameters: (a) symptomatic and subjective scale, (b) biochemical tumor marker level, and (c) objective imaging (F-FDG/Ga DOTATATE PET/CT, Tc-HYNIC TOC, ceCT), and was categorized using predefined criteria (detailed in methods). Stable disease on imaging assessment with response on symptomatic or biochemical tumor marker scales or both were included in the responder group. The study population was broadly classified into (a) metastatic GEP-NET with known primary (n=43 i.e. 86%), which was further subclassified according to the site of primary and (b) those with unknown primary (n=7 i.e. 14%). Symptomatic response: 96% of patients showed a symptomatic response or improvement in health-related quality of life, irrespective of tumor proliferation index, dual tracer imaging characteristics, and response or progression of disease in the scan. Biochemical tumor marker response: 83% of scan responders showed a decrease, 10% showed a stable value, and 7% showed an increase in tumor marker levels. Among the scan nonresponders, 67% patients showed a corresponding increase in the tumor marker level, 22% patient showed a decrease, whereas 11% showed stable values. Scan response: 31 out of total 50 patients (62%) showed a partial scan response with either a decrease in the number of somatostatin receptor (SSTR)-positive lesions or metabolic activity in F-FDG/Ga-DOTATATE PET-CT or both, 10 patients (20%) showed stable disease, and nine patients (18%) showed progressive disease. The higher objective partial scan response documented can be explained by the introduction of the F-FDG-PET/CT parameter as a determinant criterion. Among the responders category (n=41), 32 (78.04%) showed discordance between F-FDG-PET/CT-based and SSTR-based imaging, whereas eight out of nine patients with nonresponse category (88.89%) showed concordance between SSTR-based imaging and F-FDG-PET/CT. Conversely, 32 of 33 patients (96.97%) with SSTR/F-FDG discordance and nine out of 17 (52.94%) with concordance were finally classified as responders, whereas the remaining, that is, 1/33 (3.03%) in the 'discordant' category and 8/17 (47.06%) with imaging concordance were classified as nonresponders, respectively. Our data show that high pretherapy F-FDG maximum standardized uptake values were associated with increased chances of treatment refractoriness in GEP-NETs. However, symptomatic improvement was observed in most cases irrespective of grade and F-FDG uptake. High pretherapy F-FDG maximum standardized uptake value in both low-grade and high-grade NET predicted a poor outcome and was associated with disease progression. Introduction of F-FDG-PET/CT parameter as a determinant of response classification increases the percentage of objective scan responders among patients with grades I and II GEP-NETs as F-FDG activity was observed to decrease before SSTR-based imaging and more frequently compared with the latter.

Accuracy of the raw-data-based effective atomic numbers and monochromatic CT numbers for contrast medium with a dual-energy CT technique.

PubMed

Kawahara, Daisuke; Ozawa, Shuichi; Yokomachi, Kazushi; Tanaka, Sodai; Higaki, Toru; Fujioka, Chikako; Suzuki, Tatsuhiko; Tsuneda, Masato; Nakashima, Takeo; Ohno, Yoshimi; Nagata, Yasushi

2018-02-01

To evaluate the accuracy of raw-data-based effective atomic number (Z eff ) values and monochromatic CT numbers for contrast material of varying iodine concentrations, obtained using dual-energy CT. We used a tissue characterization phantom and varying concentrations of iodinated contrast medium. A comparison between the theoretical values of Z eff and that provided by the manufacturer was performed. The measured and theoretical monochromatic CT numbers at 40-130 keV were compared. The average difference between the Z eff values of lung (inhale) inserts in the tissue characterization phantom was 81.3% and the average Z eff difference was within 8.4%. The average difference between the Z eff values of the varying concentrations of iodinated contrast medium was within 11.2%. For the varying concentrations of iodinated contrast medium, the differences between the measured and theoretical monochromatic CT values increased with decreasing monochromatic energy. The Z eff and monochromatic CT numbers in the tissue characterization phantom were reasonably accurate. The accuracy of the raw-data-based Z eff values was higher than that of image-based Z eff values in the tissue-equivalent phantom. The accuracy of Z eff values in the contrast medium was in good agreement within the maximum SD found in the iodine concentration range of clinical dynamic CT imaging. Moreover, the optimum monochromatic energy for human tissue and iodinated contrast medium was found to be 70 keV. Advances in knowledge: The accuracy of the Z eff values and monochromatic CT numbers of the contrast medium created by raw-data-based, dual-energy CT could be sufficient in clinical conditions.

Rationale and Application of Tangential Scanning to Industrial Inspection of Hardwood Logs

Treesearch

Nand K. Gupta; Daniel L. Schmoldt; Bruce Isaacson

1998-01-01

Industrial computed tomography (CT) inspection of hardwood logs has some unique requirements not found in other CT applications. Sawmill operations demand that large volumes of wood be scanned quickly at high spatial resolution for extended duty cycles. Current CT scanning geometries and commercial systems have both technical and economic [imitations. Tangential...

Palonosetron versus other 5-HT₃ receptor antagonists for prevention of chemotherapy-induced nausea and vomiting in patients with hematologic malignancies treated with emetogenic chemotherapy in a hospital outpatient setting in the United States.

PubMed

Craver, Chris; Gayle, Julie; Balu, Sanjeev; Buchner, Deborah

2011-01-01

This study evaluated the rate of uncontrolled chemotherapy-induced nausea and vomiting (CINV) after initiating antiemetic prophylaxis with palonosetron versus other 5-HT₃ receptor antagonists (RAs) in patients diagnosed with hematologic malignancies (lymphoma and leukemia) and receiving highly emetogenic chemotherapy (HEC) or moderately emetogenic chemotherapy (MEC) in a hospital outpatient setting. Patients aged ≥ 18 years and diagnosed with hematologic malignancies initiating HEC or MEC and antiemetic prophylaxis with palonosetron (Group 1) and other 5-HT₃ RAs (Group 2) for the first time in a hospital outpatient setting between 4/1/2007 and 3/31/2009 were identified from the Premier Perspective Database. Within each cycle, CINV events were identified (in the hospital outpatient, inpatient, and emergency room settings) through ICD-9 codes for nausea, vomiting, and/or volume depletion (from each CT administration day 1 until the end of the CT cycle), or use of rescue medications (day 2 until the end of the CT cycle). Negative binomial distribution generalized linear multivariate regression model estimating the CINV event rate on CT, specific CT cycles, and cancer diagnosis (leukemia/lymphoma)-matched groups in the follow-up period (first of 8 cycles or 6 months) was developed. Of 971 identified patients, 211 initiated palonosetron (Group 1). Group 1 patients comprised of more females [50.2 vs. 41.4%; p = 0.0226], Whites [74.4 vs. 70.4%, and Hispanics [7.6 vs. 6.3%; all races p = 0.0105], received more HEC treatments [89.6 vs. 84.2%; all CT types p = 0.0129], and had more lymphoma diagnosed patients [89.6 vs. 76.3%; all cancer types p = 0.0033] at baseline. After controlling for differences in several demographic and clinical variables, the regression model predicted a 20.4% decrease in CINV event rate per CT cycle for Group 1 versus Group 2 patients. Study limitations include potential lack of generalizability, absence of data on certain confounders including alcohol consumption and prior history of motion sickness, potential underestimation of incidence of uncontrolled CINV, and inability to draw conclusions pertaining to cause and effect relationship. In this retrospective hospital study, patients with hematologic malignancies treated with HEC or MEC and initiated on antiemetic prophylaxis with palonosetron in the hospital outpatient setting were more likely to experience significantly lower CINV event rates (in the hospital outpatient, inpatient, and emergency room settings) versus patients initiated on other 5-HT₃ RAs.

Analysis of free breathing motion using artifact reduced 4D CT image data

NASA Astrophysics Data System (ADS)

Ehrhardt, Jan; Werner, Rene; Frenzel, Thorsten; Lu, Wei; Low, Daniel; Handels, Heinz

2007-03-01

The mobility of lung tumors during the respiratory cycle is a source of error in radiotherapy treatment planning. Spatiotemporal CT data sets can be used for studying the motion of lung tumors and inner organs during the breathing cycle. We present methods for the analysis of respiratory motion using 4D CT data in high temporal resolution. An optical flow based reconstruction method was used to generate artifact-reduced 4D CT data sets of lung cancer patients. The reconstructed 4D CT data sets were segmented and the respiratory motion of tumors and inner organs was analyzed. A non-linear registration algorithm is used to calculate the velocity field between consecutive time frames of the 4D data. The resulting velocity field is used to analyze trajectories of landmarks and surface points. By this technique, the maximum displacement of any surface point is calculated, and regions with large respiratory motion are marked. To describe the tumor mobility the motion of the lung tumor center in three orthogonal directions is displayed. Estimated 3D appearance probabilities visualize the movement of the tumor during the respiratory cycle in one static image. Furthermore, correlations between trajectories of the skin surface and the trajectory of the tumor center are determined and skin regions are identified which are suitable for prediction of the internal tumor motion. The results of the motion analysis indicate that the described methods are suitable to gain insight into the spatiotemporal behavior of anatomical and pathological structures during the respiratory cycle.

Direct comparison of (68)Ga-DOTA-TOC and (18)F-FDG PET/CT in the follow-up of patients with neuroendocrine tumour treated with the first full peptide receptor radionuclide therapy cycle.

PubMed

Nilica, Bernhard; Waitz, Dietmar; Stevanovic, Vlado; Uprimny, Christian; Kendler, Dorota; Buxbaum, Sabine; Warwitz, Boris; Gerardo, Llanos; Henninger, Benjamin; Virgolini, Irene; Rodrigues, Margarida

2016-08-01

To determine the value of (68)Ga-DOTA-TOC and (18)F-FDG PET/CT for initial and follow-up evaluation of patients with neuroendocrine tumour (NET) treated with peptide receptor radionuclide therapy (PRRT). We evaluated 66 patients who had histologically proven NET and underwent both PRRT and three combined (68)Ga-DOTA-TOC and (18)F-FDG PET/CT studies. (68)Ga-DOTA-TOC PET/CT was performed before PRRT, 3 months after completion of PRRT and after a further 6 - 9 months. (18)F-FDG PET/CT was done within 2 months of (68)Ga-DOTA-TOC PET/CT. Follow-up ranged from 11.8 to 80.0 months (mean 34.5 months). All patients were (68)Ga-DOTA-TOC PET-positive initially and at follow-up after the first full PRRT cycle. Overall, 62 of the 198 (18)F-FDG PET studies (31 %) were true-positive in 38 of the 66 patients (58 %). Of the 66 patients, 28 (5 grade 1, 23 grade 2) were (18)F-FDG-negative initially and during follow-up (group 1), 24 (5 grade 1, 13 grade 2, 6 grade 3) were (18)F-FDG-positive initially and during follow-up (group 2), 9 patients (2 grade 1, 6 grade 2, 1 grade 3) were (18)F-FDG-negative initially but (18)F-FDG-positive during follow-up (group 3), and 5 patients (all grade 2) were (18)F-FDG-positive initially but (18)F-FDG-negative during follow-up (group 4).(18)F-FDG PET showed more and/or larger metastases than (68)Ga-DOTA-TOC PET in five patients of group 2 and four patients of group 3, all with progressive disease. In three patients with progressive disease who died during follow-up tumour SUVmax increased by 41 - 82 % from the first to the last follow-up investigation. In NET patients, the presence of (18)F-FDG-positive tumours correlates strongly with a higher risk of progression. Initially, patients with (18)F-FDG-negative NET may show (18)F-FDG-positive tumours during follow-up. Also patients with grade 1 and grade 2 NET may have (18)F-FDG-positive tumours. Therefore, (18)F-FDG PET/CT is a complementary tool to (68)Ga-DOTA-TOC PET/CT with clinical relevance for molecular investigation.

Added value of cardiac computed tomography for evaluation of mechanical aortic valve: Emphasis on evaluation of pannus with surgical findings as standard reference.

PubMed

Suh, Young Joo; Lee, Sak; Im, Dong Jin; Chang, Suyon; Hong, Yoo Jin; Lee, Hye-Jeong; Hur, Jin; Choi, Byoung Wook; Chang, Byung-Chul; Shim, Chi Young; Hong, Geu-Ru; Kim, Young Jin

2016-07-01

The added value of cardiac computed tomography (CT) with transesophageal echocardiography (TEE) for evaluating mechanical aortic valve (AV) dysfunction has not yet been investigated. The purposes of this study were to investigate the added value of cardiac CT for evaluation of mechanical AVs and diagnoses of pannus compared to TEE, with surgical findings of redo-aortic valve replacement (AVR) used as a standard reference. 25 patients who underwent redo-AVR due to mechanical AV dysfunction and cardiac CT before redo-AVR were included. The presence of pannus, encroachment ratio by pannus, and limitation of motion (LOM) were evaluated on CT. The diagnostic performance of pannus detection was compared using TEE, CT, and CT+TEE, with surgical findings as a standard reference. The added value of CT for diagnosing the cause of mechanical AV dysfunction was assessed compared to TTE+TEE. In two patients, CT analysis was not feasible due to severe metallic artifacts. On CT, pannus and LOM were found in 100% (23/23) and 60.9% (14/23). TEE identified pannus in 48.0% of patients (12/25). CT, TEE, and CT+TEE correctly identified pannus with sensitivity of 92.0%, 48.0%, and 92.0%, respectively (P=0.002 for CT vs. TEE). In 11 of 13 cases (84.6%) with inconclusive or negative TEE results for pannus, CT detected the pannus. Among 13 inconclusive cases of TTE+TEE for the cause of mechanical AV dysfunction, CT suggested 6 prosthetic valve obstruction (PVO) by pannus, 4 low-flow low-gradient PVO, and one LOM without significant PVO. Cardiac CT showed added diagnostic value with TEE in the detection of pannus as the cause of mechanical AV dysfunction. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Influence of technical parameters on epicardial fat volume quantification at cardiac CT.

PubMed

Bucher, Andreas M; Joseph Schoepf, U; Krazinski, Aleksander W; Silverman, Justin; Spearman, James V; De Cecco, Carlo N; Meinel, Felix G; Vogl, Thomas J; Geyer, Lucas L

2015-06-01

To systematically analyze the influence of technical parameters on quantification of epicardial fat volume (EATV) at cardiac CT. 153 routine cardiac CT data sets were analyzed using three-dimensional pericardial border delineation. Three image series were reconstructed per patient: (a) CTAD: coronary CT angiography (CTA), diastolic phase; (b) CTAS: coronary CTA, systolic phase; (c) CaScD: non-contrast CT, diastolic phase. EATV was calculated using three different upper thresholds (-15HU, -30 HU, -45HU). Repeated measures ANOVA, Spearman's rho, and Bland Altman plots were used. Mean EATV differed between all three image series at a -30HU threshold (CTAD 87.2 ± 38.5 ml, CTAS 90.9 ± 37.7 ml, CaScD 130.7 ± 49.5 ml, P<0.001). EATV of diastolic and systolic CTA reconstructions did not differ significantly (P=0.225). Mean EATV for contrast enhanced CTA at a -15HU threshold (CTAD15 102.4 ± 43.6 ml, CTAS15 105.3 ± 42.3 ml) could be approximated most closely by non-contrast CT at -45HU threshold (CaScD45 105.3 ± 40.8 ml). The correlation was excellent: CTAS15-CTAD15, rho=0.943; CTAD15-CaScD45, rho=0.905; CTAS15-CaScD45, rho=0.924; each P<0.001). Bias values from Bland Altman Analysis were: CTAS15-CTAD15, 4.9%; CTAD15-CaScD45, -4.3%; CTAS15-CaScD45, 0.6%. Measured EATV can differ substantially between contrast enhanced and non-contrast CT studies, which can be reconciled by threshold modification. Heart cycle phase does not significantly influence EATV measurements. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Detection of West Nile virus lineage 2 in the urine of acute human infections.

PubMed

Papa, Anna; Testa, Theodolinda; Papadopoulou, Elpida

2014-12-01

West Nile virus (WNV) lineage 2 emerged in Greece in 2010 and since then outbreaks in humans have been reported for four consecutive years. Laboratory diagnosis is based mainly on serology. A real-time RT-PCR was applied on urine samples obtained from 35 patients with acute WNV infection. WNV RNA was detected in 40% of the samples with cycle threshold (CT) values ranging from 26.95 to 39.89 (mean 33.11). WNV was isolated from two of four urine samples with low CT (<30). Viral load was not associated with patients' age, sex, day of illness, presence of WNV antibodies, and neurological symptoms. However, it seems that sample shipment and storage conditions are very important for virus detection and isolation. The usefulness of the WNV RNA detection in urine as a diagnostic tool of acute WNV infections is discussed. © 2014 Wiley Periodicals, Inc.

Reducing the number of CTs performed to monitor personalized dosimetry during peptide receptor radionuclide therapy (PRRT).

PubMed

Chicheportiche, Alexandre; Artoul, Faozi; Schwartz, Arnon; Grozinsky-Glasberg, Simona; Meirovitz, Amichay; Gross, David J; Godefroy, Jeremy

2018-06-19

Peptide receptor radionuclide therapy (PRRT) with [ 177 Lu]-DOTA-TATE is an effective treatment of neuroendocrine tumors (NETs). After each cycle of treatment, patient dosimetry evaluates the radiation dose to the risk organs, kidneys, and bone marrow, the most radiosensitive tissues. Absorbed doses are calculated from the radioactivity in the blood and from single photon emission computed tomography (SPECT) images corrected by computed tomography (CT) acquired after each course of treatment. The aim of this work is to assess whether the dosimetry along all treatment cycles can be calculated using a single CT. We hypothesize that the absorbed doses to the risk organs calculated with a single CT will be accurate enough to correctly manage the patients, i.e., whether or not to continue PRRT. Twenty-four patients diagnosed with metastatic NETs undergoing PRRT with [ 177 Lu]-DOTA-TATE were retrospectively included in this study. We compared radiation doses to the kidneys and bone marrow using two protocols. In the "classical" one, dosimetry is calculated based on a SPECT and a CT after each treatment cycle. In the new protocol, dosimetry is calculated based on a SPECT study after each cycle but with the first acquired CT for all cycles. The decision whether or not to stop PRRT because of unsafe absorbed dose to the risk organs would have been the same had the classical or the new protocol been used. The agreement between the cumulative doses to the kidneys and bone marrow obtained from the two protocols was excellent with Pearson's correlation coefficients r = 0.95 and r = 0.99 (P < 0.0001) and mean relative differences of 5.30 ± 6.20% and 0.48 ± 4.88%, respectively. Dosimetry calculations for a given patient can be done using a single CT registered to serial SPECTs. This new protocol reduces the need for a hybrid camera in the follow-up of patients receiving [ 177 Lu]-DOTA-TATE.

Prediction of calcium level in melamine-related urinary calculi with helical CT: diagnostic performance evaluation and clinical significance.

PubMed

Yuan, Li; Xiaorui, Ru; Gang, Huang; Xinsheng, Xi; Xiaogang, Huang; Li, Dong; Yirong, Chen

2012-06-01

The aim of the study was to investigate the relationship between CT-attenuation and stone calcium level in melamine-related urinary calculi (MRUC). A total of 25 MRUC with known composition and calcium level were included (11 uric acid stones, 2 calcium oxalate stones and 12 mixture stones of uric acid and calcium oxalate). Of all, 18 renal stones accepted alkalization therapy except for 5 lower urinary tract stones and 2 stones of unknown position. With well-matched composition, 61 adult urinary stones were included as controls. Every stone was scanned by helical CT (80 kV/120 kV, 300 mA, pitch 0.625 mm) and the highest CT-attenuation value measured. CT-attenuation values of MRUC increased gradually from uric acid stones, mixture stones to calcium oxalate stones, but were always lower than the values of controls. Furthermore, a strong positive correlation was found between stone CT-attenuation value and stone calcium level (n = 25, r (80kV) = 0.883, p = 0.000; r (120kV) = 0.855, p = 0.000). Compared with alkalization-therapy-alone group, stone CT-attenuation values and stone calcium level in the comprehensive-therapy group were significantly greater (CT(80kV) 1,057 ± 639 vs. 172 ± 61 HU, p = 0.001; CT(120kV) 783 ± 476 vs. 162 ± 60 HU, p = 0.001; Ca 19.83 ± 7.48% vs. 1.30 ± 1.51%, p = 0.000). Fisher's exact test suggested that the stones with higher CT-attenuation values tended to resist alkalization when 400 HU served as the cutoff value (P (80kV) = 0.002, P (120kV) = 0.000). In conclusion, the study was the first to illustrate that the CT-attenuation value could reflect calcium level in MRUC and found that stones with higher CT-attenuation value were not amenable to alkalization because they probably contained greater calcium. For those patients, we believe that comprehensive therapy will be the best choice.

Experimental Treatment with Favipiravir for Ebola Virus Disease (the JIKI Trial): A Historically Controlled, Single-Arm Proof-of-Concept Trial in Guinea.

PubMed

Sissoko, Daouda; Laouenan, Cedric; Folkesson, Elin; M'Lebing, Abdoul-Bing; Beavogui, Abdoul-Habib; Baize, Sylvain; Camara, Alseny-Modet; Maes, Piet; Shepherd, Susan; Danel, Christine; Carazo, Sara; Conde, Mamoudou N; Gala, Jean-Luc; Colin, Géraldine; Savini, Hélène; Bore, Joseph Akoi; Le Marcis, Frederic; Koundouno, Fara Raymond; Petitjean, Frédéric; Lamah, Marie-Claire; Diederich, Sandra; Tounkara, Alexis; Poelart, Geertrui; Berbain, Emmanuel; Dindart, Jean-Michel; Duraffour, Sophie; Lefevre, Annabelle; Leno, Tamba; Peyrouset, Olivier; Irenge, Léonid; Bangoura, N'Famara; Palich, Romain; Hinzmann, Julia; Kraus, Annette; Barry, Thierno Sadou; Berette, Sakoba; Bongono, André; Camara, Mohamed Seto; Chanfreau Munoz, Valérie; Doumbouya, Lanciné; Souley Harouna; Kighoma, Patient Mumbere; Koundouno, Fara Roger; Réné Lolamou; Loua, Cécé Moriba; Massala, Vincent; Moumouni, Kinda; Provost, Célia; Samake, Nenefing; Sekou, Conde; Soumah, Abdoulaye; Arnould, Isabelle; Komano, Michel Saa; Gustin, Lina; Berutto, Carlotta; Camara, Diarra; Camara, Fodé Saydou; Colpaert, Joliene; Delamou, Léontine; Jansson, Lena; Kourouma, Etienne; Loua, Maurice; Malme, Kristian; Manfrin, Emma; Maomou, André; Milinouno, Adele; Ombelet, Sien; Sidiboun, Aboubacar Youla; Verreckt, Isabelle; Yombouno, Pauline; Bocquin, Anne; Carbonnelle, Caroline; Carmoi, Thierry; Frange, Pierre; Mely, Stéphane; Nguyen, Vinh-Kim; Pannetier, Delphine; Taburet, Anne-Marie; Treluyer, Jean-Marc; Kolie, Jacques; Moh, Raoul; Gonzalez, Minerva Cervantes; Kuisma, Eeva; Liedigk, Britta; Ngabo, Didier; Rudolf, Martin; Thom, Ruth; Kerber, Romy; Gabriel, Martin; Di Caro, Antonino; Wölfel, Roman; Badir, Jamal; Bentahir, Mostafa; Deccache, Yann; Dumont, Catherine; Durant, Jean-François; El Bakkouri, Karim; Gasasira Uwamahoro, Marie; Smits, Benjamin; Toufik, Nora; Van Cauwenberghe, Stéphane; Ezzedine, Khaled; D'Ortenzio, Eric; Dortenzio, Eric; Pizarro, Louis; Etienne, Aurélie; Guedj, Jérémie; Fizet, Alexandra; Barte de Sainte Fare, Eric; Murgue, Bernadette; Tran-Minh, Tuan; Rapp, Christophe; Piguet, Pascal; Poncin, Marc; Draguez, Bertrand; Allaford Duverger, Thierry; Barbe, Solenne; Baret, Guillaume; Defourny, Isabelle; Carroll, Miles; Raoul, Hervé; Augier, Augustin; Eholie, Serge P; Yazdanpanah, Yazdan; Levy-Marchal, Claire; Antierrens, Annick; Van Herp, Michel; Günther, Stephan; de Lamballerie, Xavier; Keïta, Sakoba; Mentre, France; Anglaret, Xavier; Malvy, Denis

2016-03-01

Ebola virus disease (EVD) is a highly lethal condition for which no specific treatment has proven efficacy. In September 2014, while the Ebola outbreak was at its peak, the World Health Organization released a short list of drugs suitable for EVD research. Favipiravir, an antiviral developed for the treatment of severe influenza, was one of these. In late 2014, the conditions for starting a randomized Ebola trial were not fulfilled for two reasons. One was the perception that, given the high number of patients presenting simultaneously and the very high mortality rate of the disease, it was ethically unacceptable to allocate patients from within the same family or village to receive or not receive an experimental drug, using a randomization process impossible to understand by very sick patients. The other was that, in the context of rumors and distrust of Ebola treatment centers, using a randomized design at the outset might lead even more patients to refuse to seek care. Therefore, we chose to conduct a multicenter non-randomized trial, in which all patients would receive favipiravir along with standardized care. The objectives of the trial were to test the feasibility and acceptability of an emergency trial in the context of a large Ebola outbreak, and to collect data on the safety and effectiveness of favipiravir in reducing mortality and viral load in patients with EVD. The trial was not aimed at directly informing future guidelines on Ebola treatment but at quickly gathering standardized preliminary data to optimize the design of future studies. Inclusion criteria were positive Ebola virus reverse transcription PCR (RT-PCR) test, age ≥ 1 y, weight ≥ 10 kg, ability to take oral drugs, and informed consent. All participants received oral favipiravir (day 0: 6,000 mg; day 1 to day 9: 2,400 mg/d). Semi-quantitative Ebola virus RT-PCR (results expressed in "cycle threshold" [Ct]) and biochemistry tests were performed at day 0, day 2, day 4, end of symptoms, day 14, and day 30. Frozen samples were shipped to a reference biosafety level 4 laboratory for RNA viral load measurement using a quantitative reference technique (genome copies/milliliter). Outcomes were mortality, viral load evolution, and adverse events. The analysis was stratified by age and Ct value. A "target value" of mortality was defined a priori for each stratum, to guide the interpretation of interim and final analysis. Between 17 December 2014 and 8 April 2015, 126 patients were included, of whom 111 were analyzed (adults and adolescents, ≥13 y, n = 99; young children, ≤6 y, n = 12). Here we present the results obtained in the 99 adults and adolescents. Of these, 55 had a baseline Ct value ≥ 20 (Group A Ct ≥ 20), and 44 had a baseline Ct value < 20 (Group A Ct < 20). Ct values and RNA viral loads were well correlated, with Ct = 20 corresponding to RNA viral load = 7.7 log10 genome copies/ml. Mortality was 20% (95% CI 11.6%-32.4%) in Group A Ct ≥ 20 and 91% (95% CI 78.8%-91.1%) in Group A Ct < 20. Both mortality 95% CIs included the predefined target value (30% and 85%, respectively). Baseline serum creatinine was ≥110 μmol/l in 48% of patients in Group A Ct ≥ 20 (≥300 μmol/l in 14%) and in 90% of patients in Group A Ct < 20 (≥300 μmol/l in 44%). In Group A Ct ≥ 20, 17% of patients with baseline creatinine ≥110 μmol/l died, versus 97% in Group A Ct < 20. In patients who survived, the mean decrease in viral load was 0.33 log10 copies/ml per day of follow-up. RNA viral load values and mortality were not significantly different between adults starting favipiravir within <72 h of symptoms compared to others. Favipiravir was well tolerated. In the context of an outbreak at its peak, with crowded care centers, randomizing patients to receive either standard care or standard care plus an experimental drug was not felt to be appropriate. We did a non-randomized trial. This trial reaches nuanced conclusions. On the one hand, we do not conclude on the efficacy of the drug, and our conclusions on tolerance, although encouraging, are not as firm as they could have been if we had used randomization. On the other hand, we learned about how to quickly set up and run an Ebola trial, in close relationship with the community and non-governmental organizations; we integrated research into care so that it improved care; and we generated knowledge on EVD that is useful to further research. Our data illustrate the frequency of renal dysfunction and the powerful prognostic value of low Ct values. They suggest that drug trials in EVD should systematically stratify analyses by baseline Ct value, as a surrogate of viral load. They also suggest that favipiravir monotherapy merits further study in patients with medium to high viremia, but not in those with very high viremia. ClinicalTrials.gov NCT02329054.

Gating window dependency on scanned carbon-ion beam dose distribution and imaging dose for thoracoabdominal treatment.

PubMed

Mori, Shinichiro; Karube, Masataka; Yasuda, Shigeo; Yamamoto, Naoyoshi; Tsuji, Hiroshi; Kamada, Tadashi

2017-06-01

To explore the trade-off between dose assessment and imaging dose in respiratory gating with radiographic fluoroscopic imaging, we evaluated the relationship between dose assessment and fluoroscopic imaging dose in various gating windows, retrospectively. Four-dimensional (4D) CT images acquired for 10 patients with lung and liver tumours were used for 4D treatment planning for scanned carbon ion beam. Imaging dose from two oblique directions was calculated by the number of images multiplied by the air kerma per image. Necessary beam-on time was calculated from the treatment log file. Accumulated dose distribution was calculated. The gating window was defined as tumour position not respiratory phase and changed from 0-100% duty cycle on 4DCT. These metrics were individually evaluated for every case. For lung cases, sufficient dose conformation was achieved in respective gating windows [D 95 -clinical target volume (CTV) > 99%]. V 20 -lung values for 50%- and 30%-duty cycles were 2.5% and 6.0% of that for 100%-duty cycle. Maximum doses (cord/oesophagus) for 30%-duty cycle decreased 6.8%/7.4% to those for 100%-duty cycle. For liver cases, V 10 -liver values for 50%- and 30%-duty cycles were 9.4% and 12.8% of those for 100%-duty cycle, respectively. Maximum doses (cord/oesophagus) for 50%- and 30%-duty cycles also decreased 17.2%/19.3% and 24.6%/29.8% to those for 100%-duty cycle, respectively. Total imaging doses increased 43.5% and 115.8% for 50%- and 30%-duty cycles to that for the 100%-duty cycle. When normal tissue doses are below the tolerance level, the gating window should be expanded to minimize imaging dose and treatment time. Advances in knowledge: The skin dose from imaging might not be counterbalanced to the OAR dose; however, imaging dose is a particularly important factor.

The possibility of application of spiral brain computed tomography to traumatic brain injury.

PubMed

Lim, Daesung; Lee, Soo Hoon; Kim, Dong Hoon; Choi, Dae Seub; Hong, Hoon Pyo; Kang, Changwoo; Jeong, Jin Hee; Kim, Seong Chun; Kang, Tae-Sin

2014-09-01

The spiral computed tomography (CT) with the advantage of low radiation dose, shorter test time required, and its multidimensional reconstruction is accepted as an essential diagnostic method for evaluating the degree of injury in severe trauma patients and establishment of therapeutic plans. However, conventional sequential CT is preferred for the evaluation of traumatic brain injury (TBI) over spiral CT due to image noise and artifact. We aimed to compare the diagnostic power of spiral facial CT for TBI to that of conventional sequential brain CT. We evaluated retrospectively the images of 315 traumatized patients who underwent both brain CT and facial CT simultaneously. The hemorrhagic traumatic brain injuries such as epidural hemorrhage, subdural hemorrhage, subarachnoid hemorrhage, and contusional hemorrhage were evaluated in both images. Statistics were performed using Cohen's κ to compare the agreement between 2 imaging modalities and sensitivity, specificity, positive predictive value, and negative predictive value of spiral facial CT to conventional sequential brain CT. Almost perfect agreement was noted regarding hemorrhagic traumatic brain injuries between spiral facial CT and conventional sequential brain CT (Cohen's κ coefficient, 0.912). To conventional sequential brain CT, sensitivity, specificity, positive predictive value, and negative predictive value of spiral facial CT were 92.2%, 98.1%, 95.9%, and 96.3%, respectively. In TBI, the diagnostic power of spiral facial CT was equal to that of conventional sequential brain CT. Therefore, expanded spiral facial CT covering whole frontal lobe can be applied to evaluate TBI in the future. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of Deep Cryogenic Treatment on Cyclic Fatigue of Endodontic Rotary Nickel Titanium Instruments

PubMed Central

Yazdizadeh, Mohammad; Skini, Masoumeh; Hoseini Goosheh, Seyyed Mohsen; Jafarzadeh, Mansour; Shamohammadi, Milad; Rakhshan, Vahid

2017-01-01

Introduction: Cyclic fatigue is the common reason for breakage of rotary instruments. This study was conducted to evaluate the effect of cryogenic treatment (CT) in improving the resistance to cyclic fatigue of endodontic rotary instruments. Methods and Materials: In this in vitro study, 20 RaCe and 20 Mtwo files were randomly divided into two groups of negative control and CT. CT files were stored in liquid nitrogen at -196°C for 24 h, and then were gradually warmed to the room temperature. All files were used (at torques and speeds recommended by their manufacturers) in a simulated canal with a 45° curvature until breakage. The time to fail (TF) was recorded and used to calculate the number of cycle to fail (NCF). Groups were compared using independent-samples t-test. Results: Mean NCFs were 1248.2±68.1, 1281.6±78.6, 4126.0±179.2, and 4175.4±190.1 cycles, for the Mtwo-control, Mtwo-CT, RaCe-control, and RaCe-CT, respectively. The difference between the controls and their respective CT groups were not significant (P>0.3). The difference between the systems was significant. Conclusion: Deep CT did not improve resistance to cyclic fatigue of the evaluated rotary files. PMID:28512489

Design of a multimodal (1H/23Na MR/CT) anthropomorphic thorax phantom.

PubMed

Neumann, Wiebke; Lietzmann, Florian; Schad, Lothar R; Zöllner, Frank G

2017-06-01

This work proposes a modular, anthropomorphic MR and CT thorax phantom that enables the comparison of experimental studies for quantitative evaluation of deformable, multimodal image registration algorithms and realistic multi-nuclear MR imaging techniques. A human thorax phantom was developed with insertable modules representing lung, liver, ribs and additional tracking spheres. The quality of human tissue mimicking characteristics was evaluated for 1 H and 23 Na MR as well as CT imaging. The position of landmarks in the lung lobes was tracked during CT image acquisition at several positions during breathing cycles. 1 H MR measurements of the liver were repeated after seven months to determine long term stability. The modules possess HU, T 1 and T 2 values comparable to human tissues (lung module: -756±148HU, artificial ribs: 218±56HU (low CaCO 3 concentration) and 339±121 (high CaCO 3 concentration), liver module: T 1 =790±28ms, T 2 =65±1ms). Motion analysis showed that the landmarks in the lung lobes follow a 3D trajectory similar to human breathing motion. The tracking spheres are well detectable in both CT and MRI. The parameters of the tracking spheres can be adjusted in the following ranges to result in a distinct signal: HU values from 150 to 900HU, T 1 relaxation time from 550ms to 2000ms, T 2 relaxation time from 40ms to 200ms. The presented anthropomorphic multimodal thorax phantom fulfills the demands of a simple, inexpensive system with interchangeable components. In future, the modular design allows for complementing the present set up with additional modules focusing on specific research targets such as perfusion studies, 23 Na MR quantification experiments and an increasing level of complexity for motion studies. Copyright © 2016. Published by Elsevier GmbH.

Determination of CT number and density profile of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using computed tomography imaging and electron density phantom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yusof, Mohd Fahmi Mohd, E-mail: mfahmi@usm.my; Hamid, Puteri Nor Khatijah Abdul; Tajuddin, Abdul Aziz

2015-04-29

Plug density phantoms were constructed in accordance to CT density phantom model 062M CIRS using binderless, pre-treated and tannin-based Rhizophora Spp. particleboards. The Rhizophora Spp. plug phantoms were scanned along with the CT density phantom using Siemens Somatom Definition AS CT scanner at three CT energies of 80, 120 and 140 kVp. 15 slices of images with 1.0 mm thickness each were taken from the central axis of CT density phantom for CT number and CT density profile analysis. The values were compared to water substitute plug phantom from the CT density phantom. The tannin-based Rhizophora Spp. gave the nearest valuemore » of CT number to water substitute at 80 and 120 kVp CT energies with χ{sup 2} value of 0.011 and 0.014 respectively while the binderless Rhizphora Spp. gave the nearest CT number to water substitute at 140 kVp CT energy with χ{sup 2} value of 0.023. The tannin-based Rhizophora Spp. gave the nearest CT density profile to water substitute at all CT energies. This study indicated the suitability of Rhizophora Spp. particleboard as phantom material for the use in CT imaging studies.« less

Use of an Internal Positive Control in a Multiplex Reverse Transcription-PCR To Detect West Nile Virus RNA in Mosquito Pools

PubMed Central

Eisler, Diane L.; McNabb, Alan; Jorgensen, Danielle R.; Isaac-Renton, Judith L.

2004-01-01

We report on the use of West Nile virus Armored RNA as an internal positive control (IPC) for the extraction and reverse transcription-PCR (RT-PCR) of RNA extracted from field-collected mosquitoes and on a multiplex real-time Taqman RT-PCR to simultaneously detect the 3′ noncoding region of West Nile virus and the West Nile virus NS5-2 region comprising the IPC. Mosquito pools from the province of British Columbia, Canada (n = 635), were tested in duplicate and found to be negative for West Nile virus and positive for the IPC. Known West Nile virus-positive supernatants from mosquito pools from the provinces of Alberta and Manitoba were tested in duplicate and found to be positive for both regions of the West Nile virus genome. The mean cycle threshold (Ct) value for the IPC in batch extraction controls ± 2 standard deviations was found to be 36.43 ± 1.78 cycles. IPCs of 98.4% (624) of West Nile virus-negative pools fell within this range, indicating the reproducibility of RNA extraction and RT-PCR for pools varying in mosquito genus and number. A comparison of mosquito pool genera revealed no significant genus effect on the Ct value of the IPC. The incorporation of West Nile virus Armored RNA as an IPC allows monitoring of RNA extraction and RT-PCR and detection of false-negative results due to failures in these processes or to PCR inhibition, respectively. PMID:14766868

Evaluation of a semiautomated lung mass calculation technique for internal dosimetry applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Busse, Nathan; Erwin, William; Pan, Tinsu

2013-12-15

Purpose: The authors sought to evaluate a simple, semiautomated lung mass estimation method using computed tomography (CT) scans obtained using a variety of acquisition techniques and reconstruction parameters for mass correction of medical internal radiation dose-based internal radionuclide radiation absorbed dose estimates.Methods: CT scans of 27 patients with lung cancer undergoing stereotactic body radiation therapy treatment planning with PET/CT were analyzed retrospectively. For each patient, free-breathing (FB) and respiratory-gated 4DCT scans were acquired. The 4DCT scans were sorted into ten respiratory phases, representing one complete respiratory cycle. An average CT reconstruction was derived from the ten-phase reconstructions. Mid expiration breath-holdmore » CT scans were acquired in the same session for many patients. Deep inspiration breath-hold diagnostic CT scans of many of the patients were obtained from different scanning sessions at similar time points to evaluate the effect of contrast administration and maximum inspiration breath-hold. Lung mass estimates were obtained using all CT scan types, and intercomparisons made to assess lung mass variation according to scan type. Lung mass estimates using the FB CT scans from PET/CT examinations of another group of ten male and ten female patients who were 21–30 years old and did not have lung disease were calculated and compared with reference lung mass values. To evaluate the effect of varying CT acquisition and reconstruction parameters on lung mass estimation, an anthropomorphic chest phantom was scanned and reconstructed with different CT parameters. CT images of the lungs were segmented using the OsiriX MD software program with a seed point of about −850 HU and an interval of 1000. Lung volume, and mean lung, tissue, and air HUs were recorded for each scan. Lung mass was calculated by assuming each voxel was a linear combination of only air and tissue. The specific gravity of lung volume was calculated using the formula (lung HU − air HU)/(tissue HU − air HU), and mass = specific gravity × total volume × 1.04 g/cm{sup 3}.Results: The range of calculated lung masses was 0.51–1.29 kg. The average male and female lung masses during FB CT were 0.80 and 0.71 kg, respectively. The calculated lung mass varied across the respiratory cycle but changed to a lesser degree than did lung volume measurements (7.3% versus 15.4%). Lung masses calculated using deep inspiration breath-hold and average CT were significantly larger (p < 0.05) than were some masses calculated using respiratory-phase and FB CT. Increased voxel size and smooth reconstruction kernels led to high lung mass estimates owing to partial volume effects.Conclusions: Organ mass correction is an important component of patient-specific internal radionuclide dosimetry. Lung mass calculation necessitates scan-based density correction to account for volume changes owing to respiration. The range of lung masses in the authors’ patient population represents lung doses for the same absorbed energy differing from 25% below to 64% above the dose found using reference phantom organ masses. With proper management of acquisition parameters and selection of FB or midexpiration breath hold scans, lung mass estimates with about 10% population precision may be achieved.« less

Acquiring 4D Thoracic CT Scans Using Ciné CT Acquisition

NASA Astrophysics Data System (ADS)

Low, Daniel

One method for acquiring 4D thoracic CT scans is to use ciné acquisition. Ciné acquisition is conducted by rotating the gantry and acquiring x-ray projections while keeping the couch stationary. After a complete rotation, a single set of CT slices, the number corresponding to the number of CT detector rows, is produced. The rotation period is typically sub second so each image set corresponds to a single point in time. The ciné image acquisition is repeated for at least one breathing cycle to acquire images throughout the breathing cycle. Once the images are acquired at a single couch position, the couch is moved to the abutting position and the acquisition is repeated. Post-processing of the images sets typically resorts the sets into breathing phases, stacking images from a specific phase to produce a thoracic CT scan at that phase. Benefits of the ciné acquisition protocol include, the ability to precisely identify the phase with respect to the acquired image, the ability to resort images after reconstruction, and the ability to acquire images over arbitrarily long times and for arbitrarily many images (within dose constraints).

Productivity improvement through cycle time analysis

NASA Astrophysics Data System (ADS)

Bonal, Javier; Rios, Luis; Ortega, Carlos; Aparicio, Santiago; Fernandez, Manuel; Rosendo, Maria; Sanchez, Alejandro; Malvar, Sergio

1996-09-01

A cycle time (CT) reduction methodology has been developed in the Lucent Technology facility (former AT&T) in Madrid, Spain. It is based on a comparison of the contribution of each process step in each technology with a target generated by a cycle time model. These targeted cycle times are obtained using capacity data of the machines processing those steps, queuing theory and theory of constrains (TOC) principles (buffers to protect bottleneck and low cycle time/inventory everywhere else). Overall efficiency equipment (OEE) like analysis is done in the machine groups with major differences between their target cycle time and real values. Comparisons between the current value of the parameters that command their capacity (process times, availability, idles, reworks, etc.) and the engineering standards are done to detect the cause of exceeding their contribution to the cycle time. Several friendly and graphical tools have been developed to track and analyze those capacity parameters. Specially important have showed to be two tools: ASAP (analysis of scheduling, arrivals and performance) and performer which analyzes interrelation problems among machines procedures and direct labor. The performer is designed for a detailed and daily analysis of an isolate machine. The extensive use of this tool by the whole labor force has demonstrated impressive results in the elimination of multiple small inefficiencies with a direct positive implications on OEE. As for ASAP, it shows the lot in process/queue for different machines at the same time. ASAP is a powerful tool to analyze the product flow management and the assigned capacity for interdependent operations like the cleaning and the oxidation/diffusion. Additional tools have been developed to track, analyze and improve the process times and the availability.

Fractional flow reserve by computerized tomography and subsequent coronary revascularization

PubMed Central

Packard, René R. Sevag; Li, Dong; Budoff, Matthew J.; Karlsberg, Ronald P.

2017-01-01

Aims Fractional flow reserve by computerized tomography (FFR-CT) provides non-invasive functional assessment of the hemodynamic significance of coronary artery stenosis. We determined the FFR-CT values, receiver operator characteristic (ROC) curves, and predictive ability of FFR-CT for actual standard of care guided coronary revascularization. Methods and results Consecutive outpatients who underwent coronary CT angiography (coronary CTA) followed by invasive angiography over a 24-month period from 2012 to 2014 were identified. Studies that fit inclusion criteria (n = 75 patients, mean age 66, 75% males) were sent for FFR-CT analysis, and results stratified by coronary artery calcium (CAC) scores. Coronary CTA studies were re-interpreted in a blinded manner, and baseline FFR-CT values were obtained retrospectively. Therefore, results did not interfere with clinical decision-making. Median FFR-CT values were 0.70 in revascularized (n = 69) and 0.86 in not revascularized (n = 138) coronary arteries (P < 0.001). Using clinically established significance cut-offs of FFR-CT ≤0.80 and coronary CTA ≥70% stenosis for the prediction of clinical decision-making and subsequent coronary revascularization, the positive predictive values were 74 and 88% and negative predictive values were 96 and 84%, respectively. The area under the curve (AUC) for all studied territories was 0.904 for coronary CTA, 0.920 for FFR-CT, and 0.941 for coronary CTA combined with FFR-CT (P = 0.001). With increasing CAC scores, the AUC decreased for coronary CTA but remained higher for FFR-CT (P < 0.05). Conclusion The addition of FFR-CT provides a complementary role to coronary CTA and increases the ability of a CT-based approach to identify subsequent standard of care guided coronary revascularization. PMID:27469588

Evaluation to determine the caries remineralization potential of three dentifrices: An in vitro study

PubMed Central

Balakrishnan, Arun; Jonathan, R; Benin, P; Kuumar, Arvind

2013-01-01

Aim: The aim of this study was to evaluate the remineralizing potential of three different remineralizing agents (GC tooth Mousse, Clinpro tooth crθme and SHY-NM) on demineralized tooth surfaces using micro CT and microhardness. Materials and Methods: Forty five freshly extracted mandibular premolars were collected and enamel specimens were prepared. The samples were assigned to three groups with fifteen specimens in each group. The specimens were then demineralized using McInne's demineralizing solution in two cycles. After that, remineralization was carried out in two cycles for 30 days using Casein phosphopeptide - Amorphous calcium phosphate (CPP - ACP), 0.21% sodium fluoride - Tricalcium phosphate (f-TCP) and Calcium Sodium Phosphosilicate (CSP) containing tooth pastes for groups I, II, III respectively. The specimens were evaluated for Linear attenuation co-efficient using micro CT (Scanco™) and Vicker's Micro Hardness (Schimadzu™) testing at different time periods. The results were tabulated and statistically analysed. Results: It was observed that all the three remineralizing agents used in the study significantly increased the Linear Attenuation Co-efficient and Vicker's hardness number values of the enamel specimens following 15 days and 30 days application. Conclusion: CPP – ACP showed the better remineralizing potential than the other two agents and there was no statistical significant difference between f-TCP and CSP groups. PMID:23956545

Experimental Treatment with Favipiravir for Ebola Virus Disease (the JIKI Trial): A Historically Controlled, Single-Arm Proof-of-Concept Trial in Guinea

PubMed Central

Sissoko, Daouda; Laouenan, Cedric; Folkesson, Elin; M’Lebing, Abdoul-Bing; Beavogui, Abdoul-Habib; Baize, Sylvain; Camara, Alseny-Modet; Maes, Piet; Shepherd, Susan; Danel, Christine; Carazo, Sara; Conde, Mamoudou N.; Gala, Jean-Luc; Colin, Géraldine; Savini, Hélène; Bore, Joseph Akoi; Le Marcis, Frederic; Koundouno, Fara Raymond; Petitjean, Frédéric; Lamah, Marie-Claire; Diederich, Sandra; Tounkara, Alexis; Poelart, Geertrui; Berbain, Emmanuel; Dindart, Jean-Michel; Duraffour, Sophie; Lefevre, Annabelle; Leno, Tamba; Peyrouset, Olivier; Irenge, Léonid; Bangoura, N’Famara; Palich, Romain; Hinzmann, Julia; Kraus, Annette; Barry, Thierno Sadou; Berette, Sakoba; Bongono, André; Camara, Mohamed Seto; Chanfreau Munoz, Valérie; Doumbouya, Lanciné; Souley Harouna; Kighoma, Patient Mumbere; Koundouno, Fara Roger; Réné Lolamou; Loua, Cécé Moriba; Massala, Vincent; Moumouni, Kinda; Provost, Célia; Samake, Nenefing; Sekou, Conde; Soumah, Abdoulaye; Arnould, Isabelle; Komano, Michel Saa; Gustin, Lina; Berutto, Carlotta; Camara, Diarra; Camara, Fodé Saydou; Colpaert, Joliene; Delamou, Léontine; Jansson, Lena; Kourouma, Etienne; Loua, Maurice; Malme, Kristian; Manfrin, Emma; Maomou, André; Milinouno, Adele; Ombelet, Sien; Sidiboun, Aboubacar Youla; Verreckt, Isabelle; Yombouno, Pauline; Bocquin, Anne; Carbonnelle, Caroline; Carmoi, Thierry; Frange, Pierre; Mely, Stéphane; Nguyen, Vinh-Kim; Pannetier, Delphine; Taburet, Anne-Marie; Treluyer, Jean-Marc; Kolie, Jacques; Moh, Raoul; Gonzalez, Minerva Cervantes; Kuisma, Eeva; Liedigk, Britta; Ngabo, Didier; Rudolf, Martin; Thom, Ruth; Kerber, Romy; Gabriel, Martin; Di Caro, Antonino; Wölfel, Roman; Badir, Jamal; Bentahir, Mostafa; Deccache, Yann; Dumont, Catherine; Durant, Jean-François; El Bakkouri, Karim; Gasasira Uwamahoro, Marie; Smits, Benjamin; Toufik, Nora; Van Cauwenberghe, Stéphane; Ezzedine, Khaled; Dortenzio, Eric; Pizarro, Louis; Etienne, Aurélie; Guedj, Jérémie; Fizet, Alexandra; Barte de Sainte Fare, Eric; Murgue, Bernadette; Tran-Minh, Tuan; Rapp, Christophe; Piguet, Pascal; Poncin, Marc; Draguez, Bertrand; Allaford Duverger, Thierry; Barbe, Solenne; Baret, Guillaume; Defourny, Isabelle; Carroll, Miles; Raoul, Hervé; Augier, Augustin; Eholie, Serge P.; Yazdanpanah, Yazdan; Levy-Marchal, Claire; Antierrens, Annick; Van Herp, Michel; Günther, Stephan; de Lamballerie, Xavier; Keïta, Sakoba; Mentre, France

2016-01-01

Background Ebola virus disease (EVD) is a highly lethal condition for which no specific treatment has proven efficacy. In September 2014, while the Ebola outbreak was at its peak, the World Health Organization released a short list of drugs suitable for EVD research. Favipiravir, an antiviral developed for the treatment of severe influenza, was one of these. In late 2014, the conditions for starting a randomized Ebola trial were not fulfilled for two reasons. One was the perception that, given the high number of patients presenting simultaneously and the very high mortality rate of the disease, it was ethically unacceptable to allocate patients from within the same family or village to receive or not receive an experimental drug, using a randomization process impossible to understand by very sick patients. The other was that, in the context of rumors and distrust of Ebola treatment centers, using a randomized design at the outset might lead even more patients to refuse to seek care. Therefore, we chose to conduct a multicenter non-randomized trial, in which all patients would receive favipiravir along with standardized care. The objectives of the trial were to test the feasibility and acceptability of an emergency trial in the context of a large Ebola outbreak, and to collect data on the safety and effectiveness of favipiravir in reducing mortality and viral load in patients with EVD. The trial was not aimed at directly informing future guidelines on Ebola treatment but at quickly gathering standardized preliminary data to optimize the design of future studies. Methods and Findings Inclusion criteria were positive Ebola virus reverse transcription PCR (RT-PCR) test, age ≥ 1 y, weight ≥ 10 kg, ability to take oral drugs, and informed consent. All participants received oral favipiravir (day 0: 6,000 mg; day 1 to day 9: 2,400 mg/d). Semi-quantitative Ebola virus RT-PCR (results expressed in “cycle threshold” [Ct]) and biochemistry tests were performed at day 0, day 2, day 4, end of symptoms, day 14, and day 30. Frozen samples were shipped to a reference biosafety level 4 laboratory for RNA viral load measurement using a quantitative reference technique (genome copies/milliliter). Outcomes were mortality, viral load evolution, and adverse events. The analysis was stratified by age and Ct value. A “target value” of mortality was defined a priori for each stratum, to guide the interpretation of interim and final analysis. Between 17 December 2014 and 8 April 2015, 126 patients were included, of whom 111 were analyzed (adults and adolescents, ≥13 y, n = 99; young children, ≤6 y, n = 12). Here we present the results obtained in the 99 adults and adolescents. Of these, 55 had a baseline Ct value ≥ 20 (Group A Ct ≥ 20), and 44 had a baseline Ct value < 20 (Group A Ct < 20). Ct values and RNA viral loads were well correlated, with Ct = 20 corresponding to RNA viral load = 7.7 log10 genome copies/ml. Mortality was 20% (95% CI 11.6%–32.4%) in Group A Ct ≥ 20 and 91% (95% CI 78.8%–91.1%) in Group A Ct < 20. Both mortality 95% CIs included the predefined target value (30% and 85%, respectively). Baseline serum creatinine was ≥110 μmol/l in 48% of patients in Group A Ct ≥ 20 (≥300 μmol/l in 14%) and in 90% of patients in Group A Ct < 20 (≥300 μmol/l in 44%). In Group A Ct ≥ 20, 17% of patients with baseline creatinine ≥110 μmol/l died, versus 97% in Group A Ct < 20. In patients who survived, the mean decrease in viral load was 0.33 log10 copies/ml per day of follow-up. RNA viral load values and mortality were not significantly different between adults starting favipiravir within <72 h of symptoms compared to others. Favipiravir was well tolerated. Conclusions In the context of an outbreak at its peak, with crowded care centers, randomizing patients to receive either standard care or standard care plus an experimental drug was not felt to be appropriate. We did a non-randomized trial. This trial reaches nuanced conclusions. On the one hand, we do not conclude on the efficacy of the drug, and our conclusions on tolerance, although encouraging, are not as firm as they could have been if we had used randomization. On the other hand, we learned about how to quickly set up and run an Ebola trial, in close relationship with the community and non-governmental organizations; we integrated research into care so that it improved care; and we generated knowledge on EVD that is useful to further research. Our data illustrate the frequency of renal dysfunction and the powerful prognostic value of low Ct values. They suggest that drug trials in EVD should systematically stratify analyses by baseline Ct value, as a surrogate of viral load. They also suggest that favipiravir monotherapy merits further study in patients with medium to high viremia, but not in those with very high viremia. Trial registration ClinicalTrials.gov NCT02329054 PMID:26930627

Prognostic significance of contrast-enhanced CT attenuation value in extrahepatic cholangiocarcinoma.

PubMed

Asayama, Yoshiki; Nishie, Akihiro; Ishigami, Kousei; Ushijima, Yasuhiro; Takayama, Yukihisa; Okamoto, Daisuke; Fujita, Nobuhiro; Ohtsuka, Takao; Yoshizumi, Tomoharu; Aishima, Shinichi; Oda, Yoshinao; Honda, Hiroshi

2017-06-01

To determine whether washout characteristics of dynamic contrast-enhanced computed tomography (CT) could predict survival in patients with extrahepatic cholangiocarcinoma (EHC). This study collected 46 resected cases. All cases were examined by dynamic contrast study on multidetector-row CT. Region-of-interest measurements were obtained at the non-enhanced, portal venous phase and delayed phase in the tumour and were used to calculate the washout ratio as follows: [(attenuation value at portal venous phase CT - attenuation value at delayed enhanced CT)/(attenuation value at portal venous phase CT - attenuation value at unenhanced CT)] × 100. On the basis of the median washout ratio, we classified the cases into two groups, a high-washout group and low-washout group. Associations between overall survival and various factors including washout rates were analysed. The median washout ratio was 29.4 %. Univariate analysis revealed that a lower washout ratio, venous invasion, lymphatic permeation and lymph node metastasis were associated with shorter survival. Multivariate analysis identified the lower washout ratio as an independent prognostic factor (hazard ratio, 3.768; p value, 0.027). The washout ratio obtained from the contrast-enhanced CT may be a useful imaging biomarker for the prediction of survival of patients with EHC. • Dynamic contrast study can evaluate the aggressiveness of extrahepatic cholangiocarcinoma. • A lower washout ratio was an independent prognostic factor for overall survival. • CT can predict survival and inform decisions on surgical options or chemotherapy.

Coronary artery calcium scoring does not add prognostic value to standard 64-section CT angiography protocol in low-risk patients suspected of having coronary artery disease.

PubMed

Kwon, Sung Woo; Kim, Young Jin; Shim, Jaemin; Sung, Ji Min; Han, Mi Eun; Kang, Dong Won; Kim, Ji-Ye; Choi, Byoung Wook; Chang, Hyuk-Jae

2011-04-01

To evaluate the prognostic outcome of cardiac computed tomography (CT) for prediction of major adverse cardiac events (MACEs) in low-risk patients suspected of having coronary artery disease (CAD) and to explore the differential prognostic values of coronary artery calcium (CAC) scoring and coronary CT angiography. Institutional review committee approval and informed consent were obtained. In 4338 patients who underwent 64-section CT for evaluation of suspected CAD, both CAC scoring and CT angiography were concurrently performed by using standard scanning protocols. Follow-up clinical outcome data regarding composite MACEs were procured. Multivariable Cox proportional hazards models were developed to predict MACEs. Risk-adjusted models incorporated traditional risk factors for CAC scoring and coronary CT angiography. During the mean follow-up of 828 days ± 380, there were 105 MACEs, for an event rate of 3%. The presence of obstructive CAD at coronary CT angiography had independent prognostic value, which escalated according to the number of stenosed vessels (P < .001). In the receiver operating characteristic curve (ROC) analysis, the superiority of coronary CT angiography to CAC scoring was demonstrated by a significantly greater area under the ROC curve (AUC) (0.892 vs 0.810, P < .001), whereas no significant incremental value for the addition of CAC scoring to coronary CT angiography was established (AUC = 0.892 for coronary CT angiography alone vs 0.902 with addition of CAC scoring, P = .198). Coronary CT angiography is better than CAC scoring in predicting MACEs in low-risk patients suspected of having CAD. Furthermore, the current standard multisection CT protocol (coronary CT angiography combined with CAC scoring) has no incremental prognostic value compared with coronary CT angiography alone. Therefore, in terms of determining prognosis, CAC scoring may no longer need to be incorporated in the cardiac CT protocol in this population. © RSNA, 2011.

Simulation of spatiotemporal CT data sets using a 4D MRI-based lung motion model.

PubMed

Marx, Mirko; Ehrhardt, Jan; Werner, René; Schlemmer, Heinz-Peter; Handels, Heinz

2014-05-01

Four-dimensional CT imaging is widely used to account for motion-related effects during radiotherapy planning of lung cancer patients. However, 4D CT often contains motion artifacts, cannot be used to measure motion variability, and leads to higher dose exposure. In this article, we propose using 4D MRI to acquire motion information for the radiotherapy planning process. From the 4D MRI images, we derive a time-continuous model of the average patient-specific respiratory motion, which is then applied to simulate 4D CT data based on a static 3D CT. The idea of the motion model is to represent the average lung motion over a respiratory cycle by cyclic B-spline curves. The model generation consists of motion field estimation in the 4D MRI data by nonlinear registration, assigning respiratory phases to the motion fields, and applying a B-spline approximation on a voxel-by-voxel basis to describe the average voxel motion over a breathing cycle. To simulate a patient-specific 4D CT based on a static CT of the patient, a multi-modal registration strategy is introduced to transfer the motion model from MRI to the static CT coordinates. Differences between model-based estimated and measured motion vectors are on average 1.39 mm for amplitude-based binning of the 4D MRI data of three patients. In addition, the MRI-to-CT registration strategy is shown to be suitable for the model transformation. The application of our 4D MRI-based motion model for simulating 4D CT images provides advantages over standard 4D CT (less motion artifacts, radiation-free). This makes it interesting for radiotherapy planning.

Clinics in diagnostic imaging (7). Omental caking due to ovarian carcinoma.

PubMed

Helpert, C; Peh, W C; Ng, T Y

1995-12-01

A 52-year-old Chinese woman with previously resected ovarian carcinoma was found to have ascites and a mass in the Pouch of Douglas on follow-up examination. A large omental cake was detected on computerised tomography (CT), and subsequently confirmed during laparotomy. After completion of four cycles of chemotherapy, a near complete resolution of omental metastases was demonstrated on both CT and laparotomy. The role of CT in ovarian cancer is discussed and the CT appearances of omental tumour are described.

WE-H-207A-07: Image-Based Versus Atlas-Based Internal Dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fallahpoor, M; Abbasi, M; Parach, A

Purpose: Monte Carlo (MC) simulation is known as the gold standard method for internal dosimetry. It requires radionuclide distribution from PET or SPECT and body structure from CT for accurate dose calculation. The manual or semi-automatic segmentation of organs from CT images is a major obstacle. The aim of this study is to compare the dosimetry results based on patient’s own CT and a digital humanoid phantom as an atlas with pre-specified organs. Methods: SPECT-CT images of a 50 year old woman who underwent bone pain palliation with Samarium-153 EDTMP for osseous metastases from breast cancer were used. The anatomicalmore » date and attenuation map were extracted from SPECT/CT and three XCAT digital phantoms with different BMIs (i.e. matched (38.8) and unmatched (35.5 and 36.7) with patient’s BMI that was 38.3). Segmentation of patient’s organs in CT image was performed using itk-SNAP software. GATE MC Simulator was used for dose calculation. Specific absorbed fractions (SAFs) and S-values were calculated for the segmented organs. Results: The differences between SAFs and S-values are high using different anatomical data and range from −13% to 39% for SAF values and −109% to 79% for S-values in different organs. In the spine, the clinically important target organ for Samarium Therapy, the differences in the S-values and SAF values are higher between XCAT phantom and CT when the phantom with identical BMI is employed (53.8% relative difference in S-value and 26.8% difference in SAF). However, the whole body dose values were the same between the calculations based on the CT and XCAT with different BMIs. Conclusion: The results indicated that atlas-based dosimetry using XCAT phantom even with matched BMI for patient leads to considerable errors as compared to image-based dosimetry that uses the patient’s own CT Patient-specific dosimetry using CT image is essential for accurate results.« less

Comparison of one commercial and two in-house TaqMan multiplex real-time PCR assays for detection of enteropathogenic, enterotoxigenic and enteroaggregative Escherichia coli.

PubMed

Hahn, Andreas; Luetgehetmann, Marc; Landt, Olfert; Schwarz, Norbert Georg; Frickmann, Hagen

2017-11-01

Enteropathogenic, enterotoxigenic and enteroaggregative Escherichia coli (EPEC, ETEC, EAEC) are among the most frequent causes of diarrhoea during travel or on military deployments. Cost-efficient and reliable real-time multiplex PCR (mPCR) assays are desirable for surveillance or point prevalence studies in remote and resource-limited tropical settings. We compared one commercial PCR kit and two in-house assays without using a gold standard to estimate sensitivity and specificity of each assay. Residual materials from nucleic acid extractions of stool samples from two groups with presumably different prevalences and increased likelihood of being infected or colonised by diarrhoeagenic E. coli were included in the assessment. One group comprised samples from returnees from tropical deployments, the second group was of migrants and study participants from high-endemicity settings. Each sample was assessed with all of the PCR assays. Cycle threshold (Ct) values were descriptively compared. The calculated sensitivities for the commercial test vs. the in-house tests were for EPEC 0.84 vs. 0.89 and 0.96, for ETEC 0.83 vs. 0.76 and 0.61, and for EAEC 0.69 vs. 0.54 and 0.69. False positive results were rare - specificity was 0.94 and 0.97 for two EPEC tests and 1.0 for all other tests. Most positive samples had late Ct values corresponding to low quantities of pathogens. Discordant test results were associated with late Ct values. As commercial and in-house assays showed comparable results, in-house tests can be assumed to be safe while affording considerable savings, making them a valuable alternative for surveillance testing in resource-limited tropical areas. © 2017 John Wiley & Sons Ltd.

Lessons from a large norovirus outbreak: impact of viral load, patient age and ward design on duration of symptoms and shedding and likelihood of transmission.

PubMed

Partridge, D G; Evans, C M; Raza, M; Kudesia, G; Parsons, H K

2012-05-01

Hospital norovirus outbreaks cause significant financial and operational disruption which should be minimised by optimal handling of affected areas and use of isolation facilities. To identify factors associated with increased duration of symptoms and viral excretion and increased probability of transmission. Retrospective observational study of a large norovirus outbreak at a UK teaching hospital in the winter of 2009-2010 where patients were diagnosed using a real-time polymerase chain reaction (PCR) assay. Symptom duration was significantly associated with patient age (Spearman rank correlation coefficient: 0.197; P = 0.002) but not with PCR cycle threshold (C(T)) value. Duration of viral excretion was found to be longer in patients with higher viral loads. Transmission within a ward bay was not significantly associated either with age or with C(T) value but was more likely to occur in some ward blocks than others, which may relate to differences in ward design. Transfer of patients into isolation rooms or cohorted area within two days of symptom onset did not significantly influence probability of onward transmission (52% vs 47%; P = 0.67). The presented data suggest that C(T) value may guide timing of repeat sample collection if ongoing gastrointestinal symptoms may relate to other pathologies, and that patients developing symptoms of norovirus may remain in their current bay rather than being moved into isolation facilities. The bay or ward should be closed to new admissions but it should be anticipated that duration of symptoms and therefore closure will be longer when the outbreak involves elderly patients. Copyright © 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Virus detection by PCR following vaccination of naive calves with intranasal or injectable multivalent modified-live viral vaccines.

PubMed

Walz, Paul H; Newcomer, Benjamin W; Riddell, Kay P; Scruggs, Daniel W; Cortese, Victor S

2017-09-01

We evaluated duration of PCR-positive results following administration of modified-live viral (MLV) vaccines to beef calves. Twenty beef calves were randomly assigned to either group 1 and vaccinated intranasally with a MLV vaccine containing bovine alphaherpesvirus 1 (BoHV-1), bovine respiratory syncytial virus (BRSV), and bovine parainfluenza virus 3 (BPIV-3), or to group 2 and vaccinated subcutaneously with a MLV vaccine containing bovine viral diarrhea virus 1 and 2 (BVDV-1, -2), BoHV-1, BRSV, and BPIV-3. Deep nasopharyngeal swabs (NPS) and transtracheal washes (TTW) were collected from all calves, and whole blood was collected from group 2 calves and tested by PCR. In group 1, the proportions of calves that tested PCR-positive to BVDV, BoHV-1, BRSV, and BPIV-3 on any sample at any time were 0%, 100%, 100%, and 10%, respectively. In group 1 calves, 100% of calves became PCR-positive for BoHV-1 by day 3 post-vaccination and 100% of calves became PCR-positive for BRSV by day 7 post-vaccination. In group 2, the proportions of calves that tested positive to BVDV, BoHV-1, BRSV, and BPIV-3 on any sample at any time were 50%, 40%, 10%, and 0%, respectively. All threshold cycle (Ct) values were >30 in group 2 calves, irrespective of virus; however, Ct values <25 were observed in group 1 calves from PCR-positive results for BoHV-1 and BRSV. All calves were PCR-negative for all viruses after day 28. Following intranasal MLV viral vaccination, PCR results and Ct values for BRSV and BoHV-1 suggest that attempts to differentiate vaccine virus from natural infection is unreliable.

Determination of dosimetric quantities in pediatric abdominal computed tomography scans*

PubMed Central

Jornada, Tiago da Silva; da Silva, Teógenes Augusto

2014-01-01

Objective Aiming at contributing to the knowledge on doses in computed tomography (CT), this study has the objective of determining dosimetric quantities associated with pediatric abdominal CT scans, comparing the data with diagnostic reference levels (DRL). Materials and methods The study was developed with a Toshiba Asteion single-slice CT scanner and a GE BrightSpeed multi-slice CT unit in two hospitals. Measurements were performed with a pencil-type ionization chamber and a 16 cm-diameter polymethylmethacrylate trunk phantom. Results No significant difference was observed in the values for weighted air kerma index (CW), but the differences were relevant in values for volumetric air kerma index (CVOL), air kerma-length product (PKL,CT) and effective dose. Conclusion Only the CW values were lower than the DRL, suggesting that dose optimization might not be necessary. However, PKL,CT and effective dose values stressed that there still is room for reducing pediatric radiation doses. The present study emphasizes the importance of determining all dosimetric quantities associated with CT scans. PMID:25741103

Acceptance test of a commercially available software for automatic image registration of computed tomography (CT), magnetic resonance imaging (MRI) and 99mTc-methoxyisobutylisonitrile (MIBI) single-photon emission computed tomography (SPECT) brain images.

PubMed

Loi, Gianfranco; Dominietto, Marco; Manfredda, Irene; Mones, Eleonora; Carriero, Alessandro; Inglese, Eugenio; Krengli, Marco; Brambilla, Marco

2008-09-01

This note describes a method to characterize the performances of image fusion software (Syntegra) with respect to accuracy and robustness. Computed tomography (CT), magnetic resonance imaging (MRI), and single-photon emission computed tomography (SPECT) studies were acquired from two phantoms and 10 patients. Image registration was performed independently by two couples composed of one radiotherapist and one physicist by means of superposition of anatomic landmarks. Each couple performed jointly and saved the registration. The two solutions were averaged to obtain the gold standard registration. A new set of estimators was defined to identify translation and rotation errors in the coordinate axes, independently from point position in image field of view (FOV). Algorithms evaluated were local correlation (LC) for CT-MRI, normalized mutual information (MI) for CT-MRI, and CT-SPECT registrations. To evaluate accuracy, estimator values were compared to limiting values for the algorithms employed, both in phantoms and in patients. To evaluate robustness, different alignments between images taken from a sample patient were produced and registration errors determined. LC algorithm resulted accurate in CT-MRI registrations in phantoms, but exceeded limiting values in 3 of 10 patients. MI algorithm resulted accurate in CT-MRI and CT-SPECT registrations in phantoms; limiting values were exceeded in one case in CT-MRI and never reached in CT-SPECT registrations. Thus, the evaluation of robustness was restricted to the algorithm of MI both for CT-MRI and CT-SPECT registrations. The algorithm of MI proved to be robust: limiting values were not exceeded with translation perturbations up to 2.5 cm, rotation perturbations up to 10 degrees and roto-translational perturbation up to 3 cm and 5 degrees.

Conventional multi-slice computed tomography (CT) and cone-beam CT (CBCT) for computer-assisted implant placement. Part I: relationship of radiographic gray density and implant stability.

PubMed

Arisan, Volkan; Karabuda, Zihni Cüneyt; Avsever, Hakan; Özdemir, Tayfun

2013-12-01

The relationship of conventional multi-slice computed tomography (CT)- and cone beam CT (CBCT)-based gray density values and the primary stability parameters of implants that were placed by stereolithographic surgical guides were analyzed in this study. Eighteen edentulous jaws were randomly scanned by a CT (CT group) or a CBCT scanner (CBCT group) and radiographic gray density was measured from the planned implants. A total of 108 implants were placed, and primary stability parameters were measured by insertion torque value (ITV) and resonance frequency analysis (RFA). Radiographic and subjective bone quality classification (BQC) was also classified. Results were analyzed by correlation tests and multiple regressions (p < .05). CBCT-based gray density values (765 ± 97.32 voxel value) outside the implants were significantly higher than those of CT-based values (668.4 ± 110 Hounsfield unit, p < .001). Significant relations were found among the gray density values outside the implants, ITV (adjusted r(2)  = 0.6142, p = .001 and adjusted r(2)  = 0.5166, p = .0021), and RFA (adjusted r(2)  = 0.5642, p = .0017 and adjusted r(2)  = 0.5423, p = .0031 for CT and CBCT groups, respectively). Data from radiographic and subjective BQC were also in agreement. Similar to the gray density values of CT, that of CBCT could also be predictive for the subjective BQC and primary implant stability. Results should be confirmed on different CBCT scanners. © 2012 Wiley Periodicals, Inc.

The predictive value of single-photon emission computed tomography/computed tomography for sentinel lymph node localization in head and neck cutaneous malignancy.

PubMed

Remenschneider, Aaron K; Dilger, Amanda E; Wang, Yingbing; Palmer, Edwin L; Scott, James A; Emerick, Kevin S

2015-04-01

Preoperative localization of sentinel lymph nodes in head and neck cutaneous malignancies can be aided by single-photon emission computed tomography/computed tomography (SPECT/CT); however, its true predictive value for identifying lymph nodes intraoperatively remains unquantified. This study aims to understand the sensitivity, specificity, and positive and negative predictive values of SPECT/CT in sentinel lymph node biopsy for cutaneous malignancies of the head and neck. Blinded retrospective imaging review with comparison to intraoperative gamma probe confirmed sentinel lymph nodes. A consecutive series of patients with a head and neck cutaneous malignancy underwent preoperative SPECT/CT followed by sentinel lymph node biopsy with a gamma probe. Two nuclear medicine physicians, blinded to clinical data, independently reviewed each SPECT/CT. Activity within radiographically defined nodal basins was recorded and compared to intraoperative gamma probe findings. Sensitivity, specificity, and negative and positive predictive values were calculated with subgroup stratification by primary tumor site. Ninety-two imaging reads were performed on 47 patients with cutaneous malignancy who underwent SPECT/CT followed by sentinel lymph node biopsy. Overall sensitivity was 73%, specificity 92%, positive predictive value 54%, and negative predictive value 96%. The predictive ability of SPECT/CT to identify the basin or an adjacent basin containing the single hottest node was 92%. SPECT/CT overestimated uptake by an average of one nodal basin. In the head and neck, SPECT/CT has higher reliability for primary lesions of the eyelid, scalp, and cheek. SPECT/CT has high sensitivity, specificity, and negative predictive value, but may overestimate relevant nodal basins in sentinel lymph node biopsy. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

The Value of Lung Cancer CT Screening: It Is All about Implementation.

PubMed

Goulart, Bernardo H L

2015-01-01

Hospitals have been gradually implementing new lung cancer CT screening programs following the release of the U.S. Preventive Services Task Force grade B recommendation to screen individuals at high risk for lung cancer. Policy makers have legitimately questioned whether adoption of CT screening in the community will reproduce the mortality benefits seen in the National Lung Screening Trial (NLST) and whether the benefits of screening will justify the potentially high costs. Although three annual CT screening exams proved cost-effective for the patient population enrolled in the NLST, uncertainty still exists about whether CT screening will be cost-effective in practice. The value of CT screening will depend largely on the strategies used to implement it. This manuscript reviews the current reimbursement policies for CT screening and explains the relationship between implementation strategies and screening value on the basis of the NLST cost-effectiveness analysis and other published data. A subsequent discussion ensues about the potential implementation inefficiencies that can negatively affect the value of CT screening (e.g., selection of low-risk individuals for screening, inappropriate follow-up visits for screening-detected lung nodules, failure to offer smoking cessation interventions, and overuse of medical resources for clinically irrelevant incidental findings) and the actions that can be taken to mitigate these inefficiencies and increase the value of screening.

Issues in quantification of registered respiratory gated PET/CT in the lung.

PubMed

Cuplov, Vesna; Holman, Beverley F; McClelland, Jamie; Modat, Marc; Hutton, Brian F; Thielemans, Kris

2017-12-14

PET/CT quantification of lung tissue is limited by several difficulties: the lung density and local volume changes during respiration, the anatomical mismatch between PET and CT and the relative contributions of tissue, air and blood to the PET signal (the tissue fraction effect). Air fraction correction (AFC) has been shown to improve PET image quantification in the lungs. Methods to correct for the movement and anatomical mismatch involve respiratory gating and image registration techniques. While conventional registration methods only account for spatial mismatch, the Jacobian determinant of the deformable registration transformation field can be used to estimate local volume changes and could therefore potentially be used to correct (i.e. Jacobian Correction, JC) the PET signal for changes in concentration due to local volume changes. This work aims to investigate the relationship between variations in the lung due to respiration, specifically density, tracer concentration and local volume changes. In particular, we study the effect of AFC and JC on PET quantitation after registration of respiratory gated PET/CT patient data. Six patients suffering from lung cancer with solitary pulmonary nodules underwent [Formula: see text]F-FDG PET/cine-CT. The PET data were gated into six respiratory gates using displacement gating based on a real-time position management (RPM) signal and reconstructed with matched gated CT. The PET tracer concentration and tissue density were extracted from registered gated PET and CT images before and after corrections (AFC or JC) and compared to the values from the reference images. Before correction, we observed a linear correlation between the PET tracer concentration values and density. Across all gates and patients, the maximum relative change in PET tracer concentration before (after) AFC was found to be 16.2% (4.1%) and the maximum relative change in tissue density and PET tracer concentration before (after) JC was found to be 17.1% (5.5%) and 16.2% (6.8%) respectively. Overall our results show that both AFC or JC largely explain the observed changes in PET tracer activity over the respiratory cycle. We also speculate that a second order effect is related to change in fluid content but this needs further investigation. Consequently, either AFC or JC is recommended when combining lung PET images from different gates to reduce noise.

Issues in quantification of registered respiratory gated PET/CT in the lung

NASA Astrophysics Data System (ADS)

Cuplov, Vesna; Holman, Beverley F.; McClelland, Jamie; Modat, Marc; Hutton, Brian F.; Thielemans, Kris

2018-01-01

PET/CT quantification of lung tissue is limited by several difficulties: the lung density and local volume changes during respiration, the anatomical mismatch between PET and CT and the relative contributions of tissue, air and blood to the PET signal (the tissue fraction effect). Air fraction correction (AFC) has been shown to improve PET image quantification in the lungs. Methods to correct for the movement and anatomical mismatch involve respiratory gating and image registration techniques. While conventional registration methods only account for spatial mismatch, the Jacobian determinant of the deformable registration transformation field can be used to estimate local volume changes and could therefore potentially be used to correct (i.e. Jacobian Correction, JC) the PET signal for changes in concentration due to local volume changes. This work aims to investigate the relationship between variations in the lung due to respiration, specifically density, tracer concentration and local volume changes. In particular, we study the effect of AFC and JC on PET quantitation after registration of respiratory gated PET/CT patient data. Six patients suffering from lung cancer with solitary pulmonary nodules underwent 18 F-FDG PET/cine-CT. The PET data were gated into six respiratory gates using displacement gating based on a real-time position management (RPM) signal and reconstructed with matched gated CT. The PET tracer concentration and tissue density were extracted from registered gated PET and CT images before and after corrections (AFC or JC) and compared to the values from the reference images. Before correction, we observed a linear correlation between the PET tracer concentration values and density. Across all gates and patients, the maximum relative change in PET tracer concentration before (after) AFC was found to be 16.2% (4.1%) and the maximum relative change in tissue density and PET tracer concentration before (after) JC was found to be 17.1% (5.5%) and 16.2% (6.8%) respectively. Overall our results show that both AFC or JC largely explain the observed changes in PET tracer activity over the respiratory cycle. We also speculate that a second order effect is related to change in fluid content but this needs further investigation. Consequently, either AFC or JC is recommended when combining lung PET images from different gates to reduce noise.

Ameliorative effects of melatonin administration and photoperiods on diurnal fluctuations in cloacal temperature of Marshall broiler chickens during the hot dry season

NASA Astrophysics Data System (ADS)

Sinkalu, Victor O.; Ayo, Joseph O.; Adelaiye, Alexander B.; Hambolu, Joseph O.

2015-01-01

Experiments were performed with the aim of determining the effect of melatonin administration on diurnal fluctuations in cloacal temperature (CT) of Marshall broiler chickens during the hot dry season. Birds in group I (12L:12D cycle) were raised under natural photoperiod of 12-h light and 12-h darkness, without melatonin supplementation, while those in group II (LL) were kept under 24-h continuous lighting, without melatonin administration. Broiler chickens in group III (LL + melatonin) were raised under 24-h continuous lighting, with melatonin supplementation at 0.5 mg/kg per os. The cloacal temperatures of 15 labeled broiler chickens from each group were measured at 6:00, 13:00, and 19:00 h, 7 days apart, from days 14-42. Temperature-humidity index was highest at day 14 of the study, with the value of 36.72 ± 0.82 °C but lowest at day 28 with the value of 30.91 ± 0.80 °C ( P < 0.0001). The overall mean hourly cloacal temperature value of 41.51 ± 0.03 °C obtained in the 12L:12D cycle birds was significantly higher ( P < 0.001) than the value of 41.16 ± 0.03 °C recorded in the melatonin-treated group but lower than that of 41.65 ± 0.03 °C obtained in the LL birds. Mortality due to hyperthermia commenced at day 28 in both 12L:12D cycle and LL broiler chickens but was delayed till day 42 in LL + MEL broiler chickens. In conclusion, melatonin administration alleviated the deleterious effects of heat stress on broiler chickens by maintaining their cloacal temperature at relatively low values.

A cytotoxic protein (BF-CT1) purified from Bungarus fasciatus venom acts through apoptosis, modulation of PI3K/AKT, MAPKinase pathway and cell cycle regulation.

PubMed

Bhattacharya, Shamik; Das, Tanaya; Biswas, Archita; Gomes, Aparna; Gomes, Antony; Dungdung, Sandhya Rekha

2013-11-01

BF-CT1, a 13 kDa protein isolated from Bungarus fasciatus snake venom through CM cellulose ion exchange chromatography at 0.02 M NaCl salt gradient showed cytotoxicity in in vitro and in vivo experimental models. In in vivo Ehrlich ascites carcinoma (EAC) induced BALB/c mice model, BF-CT1 treatment reduced EAC cell count significantly through apoptotic cell death pathway as evidenced by FACS analysis, increased caspase 3, 9 activity and altered pro, antiapoptotic protein expression. BF-CT1 treatment caused cell shrinkage, chromatin condensation and induced apoptosis through increased caspase 3, caspase 9 activity, PARP cleavage and down regulation of heat shock proteins in U937 leukemic cell line. Cytosolic cytochrome C production was increased after BF-CT1 treatment upon U937 cell line. BF-CT1 treated U937 cell showed cell cycle arrest at sub G1 phase through cyclin D and CDK down regulation with up regulation of p15 and p16. It also down regulated PI3K/AKT pathway and MAPkinase pathway and promoted apoptosis and regulated cell proliferation in U937 cells. BF-CT1 prevented angiogenesis in in vitro U937 cell line through decreased VEGF and TGF-β1 production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Patient-Specific Circulating Tumor DNA Detection during Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer.

PubMed

Riva, Francesca; Bidard, Francois-Clement; Houy, Alexandre; Saliou, Adrien; Madic, Jordan; Rampanou, Aurore; Hego, Caroline; Milder, Maud; Cottu, Paul; Sablin, Marie-Paule; Vincent-Salomon, Anne; Lantz, Olivier; Stern, Marc-Henri; Proudhon, Charlotte; Pierga, Jean-Yves

2017-03-01

In nonmetastatic triple-negative breast cancer (TNBC) patients, we investigated whether circulating tumor DNA (ctDNA) detection can reflect the tumor response to neoadjuvant chemotherapy (NCT) and detect minimal residual disease after surgery. Ten milliliters of plasma were collected at 4 time points: before NCT; after 1 cycle; before surgery; after surgery. Customized droplet digital PCR (ddPCR) assays were used to track tumor protein p53 ( TP53 ) mutations previously characterized in tumor tissue by massively parallel sequencing (MPS). Forty-six patients with nonmetastatic TNBC were enrolled. TP53 mutations were identified in 40 of them. Customized ddPCR probes were validated for 38 patients, with excellent correlation with MPS ( r = 0.99), specificity (≥2 droplets/assay), and sensitivity (at least 0.1%). At baseline, ctDNA was detected in 27/36 patients (75%). Its detection was associated with mitotic index ( P = 0.003), tumor grade ( P = 0.003), and stage ( P = 0.03). During treatment, we observed a drop of ctDNA levels in all patients but 1. No patient had detectable ctDNA after surgery. The patient with rising ctDNA levels experienced tumor progression during NCT. Pathological complete response (16/38 patients) was not correlated with ctDNA detection at any time point. ctDNA positivity after 1 cycle of NCT was correlated with shorter disease-free ( P < 0.001) and overall ( P = 0.006) survival. Customized ctDNA detection by ddPCR achieved a 75% detection rate at baseline. During NCT, ctDNA levels decreased quickly and minimal residual disease was not detected after surgery. However, a slow decrease of ctDNA level during NCT was strongly associated with shorter survival. © 2016 American Association for Clinical Chemistry.

Transcranial direct current stimulation and cognitive training in the rehabilitation of Alzheimer disease: A case study.

PubMed

Penolazzi, Barbara; Bergamaschi, Susanna; Pastore, Massimiliano; Villani, Daniele; Sartori, Giuseppe; Mondini, Sara

2015-01-01

In the present study we tested the cognitive effects of transcranial direct current stimulation (tDCS) in a case of probable Alzheimer disease (AD). The patient (male, 60 years, mild AD) underwent two cycles of treatments, separated by 2 months. In the first cycle, active stimulation (10 sessions, 2 mA for 20 min; anode over the left dorsolateral prefrontal cortex) was followed by computerised tasks (CTs) specifically chosen to engage the most impaired cognitive processes in the patient (tDCS+CT condition). In the second cycle, which was structured as the first, CTs were administered after placebo stimulation (sham+CT condition). Effects on cognitive performance were evaluated not only by the CTs, but also by neuropsychological tests assessing global cognitive functioning. Statistical analyses revealed that whereas the tDCS+CT condition had few effects on the CTs, it induced a stability of the patient's global cognitive functioning lasting approximately 3 months, which was not achieved when the patient underwent sham+CT condition. Therefore, the synergetic use of tDCS and CTs appeared to slow down the cognitive decline of our patient. This preliminary result, although in need of further confirmation, suggests the potentiality of tDCS as an adjuvant tool for cognitive rehabilitation in AD.

Metastatic renal cell carcinoma: CT-guided immunotherapy as a technically feasible and safe approach to delivery of gene therapy for treatment.

PubMed

Suh, Robert D; Goldin, Jonathan G; Wallace, Amanda B; Sheehan, Ramon E; Heinze, Stefan B; Gitlitz, Barbara J; Figlin, Robert A

2004-05-01

To assess the technical feasibility and safety of weekly outpatient percutaneous computed tomographic (CT)-guided intratumoral injections of interleukin-2 (IL-2) plasmid DNA in a wide variety of superficial and deep tumor sites. Twenty-nine patients with metastatic renal cell carcinoma and a total of 30 lesions measuring 1.0 cm(2) or greater in accessible thoracic (n = 15) or abdominal (n = 15) locations underwent up to three cycles of six weekly intratumoral IL-2 plasmid DNA injections. CT was used to guide needle placement and injection. After injection cycle 1, patients whose tumors demonstrated stable (< or =25% increase and < or =50% decrease in product of lesion diameters) or decreased size (>50% decrease in product of lesion diameters) advanced to injection cycle 2. Patients whose lesions decreased in size by more than 50% over the course of injection cycle 2 were eligible to begin injection cycle 3. An acceptable safety and technical feasibility profile for this technique was deemed to be (a) a safety and feasibility profile similar to that of single-needle biopsy and (b) an absence of serious adverse events (as defined in Title 21 of the Code of Federal Regulations) and/or unacceptable toxicities (as graded according to the National Cancer Institute Common Toxicity Criteria). A total of 284 intratumoral injections were performed, with a mean of 9.8 injections (range, 6-18 injections) received by each patient. Technical success (needle placement and injection of gene therapy agent) was achieved in all cases. Complications were experienced after 42 (14.8%) of the 284 injections. The most common complication was pneumothorax (at 32 [28.6%] of 112 intrathoracic injections), for which only one patient required catheter drainage. Complications occurred randomly throughout injection cycles and did not appear to increase as patients received more injections (P =.532). No patient experienced serious adverse events or unacceptable toxicities. Percutaneous CT-guided intratumoral immunotherapy injections are technically feasible and can be safely performed.

Feasibility of Computed Tomography-Guided Methods for Spatial Normalization of Dopamine Transporter Positron Emission Tomography Image.

PubMed

Kim, Jin Su; Cho, Hanna; Choi, Jae Yong; Lee, Seung Ha; Ryu, Young Hoon; Lyoo, Chul Hyoung; Lee, Myung Sik

2015-01-01

Spatial normalization is a prerequisite step for analyzing positron emission tomography (PET) images both by using volume-of-interest (VOI) template and voxel-based analysis. Magnetic resonance (MR) or ligand-specific PET templates are currently used for spatial normalization of PET images. We used computed tomography (CT) images acquired with PET/CT scanner for the spatial normalization for [18F]-N-3-fluoropropyl-2-betacarboxymethoxy-3-beta-(4-iodophenyl) nortropane (FP-CIT) PET images and compared target-to-cerebellar standardized uptake value ratio (SUVR) values with those obtained from MR- or PET-guided spatial normalization method in healthy controls and patients with Parkinson's disease (PD). We included 71 healthy controls and 56 patients with PD who underwent [18F]-FP-CIT PET scans with a PET/CT scanner and T1-weighted MR scans. Spatial normalization of MR images was done with a conventional spatial normalization tool (cvMR) and with DARTEL toolbox (dtMR) in statistical parametric mapping software. The CT images were modified in two ways, skull-stripping (ssCT) and intensity transformation (itCT). We normalized PET images with cvMR-, dtMR-, ssCT-, itCT-, and PET-guided methods by using specific templates for each modality and measured striatal SUVR with a VOI template. The SUVR values measured with FreeSurfer-generated VOIs (FSVOI) overlaid on original PET images were also used as a gold standard for comparison. The SUVR values derived from all four structure-guided spatial normalization methods were highly correlated with those measured with FSVOI (P < 0.0001). Putaminal SUVR values were highly effective for discriminating PD patients from controls. However, the PET-guided method excessively overestimated striatal SUVR values in the PD patients by more than 30% in caudate and putamen, and thereby spoiled the linearity between the striatal SUVR values in all subjects and showed lower disease discrimination ability. Two CT-guided methods showed comparable capability with the MR-guided methods in separating PD patients from controls and showed better correlation between putaminal SUVR values and the parkinsonian motor severity than the PET-guided method. CT-guided spatial normalization methods provided reliable striatal SUVR values comparable to those obtained with MR-guided methods. CT-guided methods can be useful for analyzing dopamine transporter PET images when MR images are unavailable.

Feasibility of Computed Tomography-Guided Methods for Spatial Normalization of Dopamine Transporter Positron Emission Tomography Image

PubMed Central

Kim, Jin Su; Cho, Hanna; Choi, Jae Yong; Lee, Seung Ha; Ryu, Young Hoon; Lyoo, Chul Hyoung; Lee, Myung Sik

2015-01-01

Background Spatial normalization is a prerequisite step for analyzing positron emission tomography (PET) images both by using volume-of-interest (VOI) template and voxel-based analysis. Magnetic resonance (MR) or ligand-specific PET templates are currently used for spatial normalization of PET images. We used computed tomography (CT) images acquired with PET/CT scanner for the spatial normalization for [18F]-N-3-fluoropropyl-2-betacarboxymethoxy-3-beta-(4-iodophenyl) nortropane (FP-CIT) PET images and compared target-to-cerebellar standardized uptake value ratio (SUVR) values with those obtained from MR- or PET-guided spatial normalization method in healthy controls and patients with Parkinson’s disease (PD). Methods We included 71 healthy controls and 56 patients with PD who underwent [18F]-FP-CIT PET scans with a PET/CT scanner and T1-weighted MR scans. Spatial normalization of MR images was done with a conventional spatial normalization tool (cvMR) and with DARTEL toolbox (dtMR) in statistical parametric mapping software. The CT images were modified in two ways, skull-stripping (ssCT) and intensity transformation (itCT). We normalized PET images with cvMR-, dtMR-, ssCT-, itCT-, and PET-guided methods by using specific templates for each modality and measured striatal SUVR with a VOI template. The SUVR values measured with FreeSurfer-generated VOIs (FSVOI) overlaid on original PET images were also used as a gold standard for comparison. Results The SUVR values derived from all four structure-guided spatial normalization methods were highly correlated with those measured with FSVOI (P < 0.0001). Putaminal SUVR values were highly effective for discriminating PD patients from controls. However, the PET-guided method excessively overestimated striatal SUVR values in the PD patients by more than 30% in caudate and putamen, and thereby spoiled the linearity between the striatal SUVR values in all subjects and showed lower disease discrimination ability. Two CT-guided methods showed comparable capability with the MR-guided methods in separating PD patients from controls and showed better correlation between putaminal SUVR values and the parkinsonian motor severity than the PET-guided method. Conclusion CT-guided spatial normalization methods provided reliable striatal SUVR values comparable to those obtained with MR-guided methods. CT-guided methods can be useful for analyzing dopamine transporter PET images when MR images are unavailable. PMID:26147749

Prognostic implications of 62Cu-diacetyl-bis (N4-methylthiosemicarbazone) PET/CT in patients with glioma.

PubMed

Toriihara, Akira; Ohtake, Makoto; Tateishi, Kensuke; Hino-Shishikura, Ayako; Yoneyama, Tomohiro; Kitazume, Yoshio; Inoue, Tomio; Kawahara, Nobutaka; Tateishi, Ukihide

2018-05-01

The potential of positron emission tomography/computed tomography using 62 Cu-diacetyl-bis (N 4 -methylthiosemicarbazone) ( 62 Cu-ATSM PET/CT), which was originally developed as a hypoxic tracer, to predict therapeutic resistance and prognosis has been reported in various cancers. Our purpose was to investigate prognostic value of 62 Cu-ATSM PET/CT in patients with glioma, compared to PET/CT using 2-deoxy-2-[ 18 F]fluoro-D-glucose ( 18 F-FDG). 56 patients with glioma of World Health Organization grade 2-4 were enrolled. All participants had undergone both 62 Cu-ATSM PET/CT and 18 F-FDG PET/CT within mean 33.5 days prior to treatment. Maximum standardized uptake value and tumor/background ratio were calculated within areas of increased radiotracer uptake. The prognostic significance for progression-free survival and overall survival were assessed by log-rank test and Cox's proportional hazards model. Disease progression and death were confirmed in 37 and 27 patients in follow-up periods, respectively. In univariate analysis, there was significant difference of both progression-free survival and overall survival in age, tumor grade, history of chemoradiotherapy, maximum standardized uptake value and tumor/background ratio calculated using 62 Cu-ATSM PET/CT. Multivariate analysis revealed that maximum standardized uptake value calculated using 62 Cu-ATSM PET/CT was an independent predictor of both progression-free survival and overall survival (p < 0.05). In a subgroup analysis including patients of grade 4 glioma, only the maximum standardized uptake values calculated using 62 Cu-ATSM PET/CT showed significant difference of progression-free survival (p < 0.05). 62 Cu-ATSM PET/CT is a more promising imaging method to predict prognosis of patients with glioma compared to 18 F-FDG PET/CT.

The value of FDG PET/CT for follow-up of patients with melanoma: a retrospective analysis

PubMed Central

Vensby, Philip H; Schmidt, Grethe; Kjær, Andreas; Fischer, Barbara M

2017-01-01

The incidence of melanoma (MM) is among the fastest rising cancers in the western countries. Positron Emission Tomography with Computed Tomography (PET/CT) is a valuable non-invasive tool for the diagnosis and staging of patients with MM. However, research on the value of PET/CT in follow-up of melanoma patients is limited. This study assesses the diagnostic value of PET/CT for follow-up after melanoma surgery. This retrospective study includes patients with MM who performed at least one PET/CT scan after initial surgery and staging. PET/CT findings were compared to histology, MRI or fine needle aspiration (FNA) to estimate the diagnostic accuracy. The diagnostic performance of PET/CT performed in patients with and without a clinical suspicion of relapse was compared. 238 patients (526 scans) were included. Of the 526 scans 130 (25%) scans were PET-positive, 365 (69%) PET-negative, and 28 (5%) had equivocal findings. Sensitivity was 89% [0.82-0.94], specificity 92% [0.89-0.95], positive and negative predictive values of 78% [0.70-0.84] and 97% [0.94-0.98] respectively. When stratified for reason of referral there was no statistical significant difference in the diagnostic accuracy of PET/CT between patients referred with or without a clinical suspicion of relapse. This study demonstrates that PET/CT despite a moderate sensitivity has a high negative predictive value in the follow-up of melanoma patients. Thus, a negative PET/CT-scan essentially rules out relapse. However, the frequency of false positive findings is relatively high, especially among patients undergoing a “routine” PET/CT with no clinical suspicion of relapse, potentially causing anxiety and leading to further diagnostic procedures. PMID:29348980

The value of FDG PET/CT for follow-up of patients with melanoma: a retrospective analysis.

PubMed

Vensby, Philip H; Schmidt, Grethe; Kjær, Andreas; Fischer, Barbara M

2017-01-01

The incidence of melanoma (MM) is among the fastest rising cancers in the western countries. Positron Emission Tomography with Computed Tomography (PET/CT) is a valuable non-invasive tool for the diagnosis and staging of patients with MM. However, research on the value of PET/CT in follow-up of melanoma patients is limited. This study assesses the diagnostic value of PET/CT for follow-up after melanoma surgery. This retrospective study includes patients with MM who performed at least one PET/CT scan after initial surgery and staging. PET/CT findings were compared to histology, MRI or fine needle aspiration (FNA) to estimate the diagnostic accuracy. The diagnostic performance of PET/CT performed in patients with and without a clinical suspicion of relapse was compared. 238 patients (526 scans) were included. Of the 526 scans 130 (25%) scans were PET-positive, 365 (69%) PET-negative, and 28 (5%) had equivocal findings. Sensitivity was 89% [0.82-0.94], specificity 92% [0.89-0.95], positive and negative predictive values of 78% [0.70-0.84] and 97% [0.94-0.98] respectively. When stratified for reason of referral there was no statistical significant difference in the diagnostic accuracy of PET/CT between patients referred with or without a clinical suspicion of relapse. This study demonstrates that PET/CT despite a moderate sensitivity has a high negative predictive value in the follow-up of melanoma patients. Thus, a negative PET/CT-scan essentially rules out relapse. However, the frequency of false positive findings is relatively high, especially among patients undergoing a "routine" PET/CT with no clinical suspicion of relapse, potentially causing anxiety and leading to further diagnostic procedures.

Consolidation paclitaxel is more cost-effective than bevacizumab following upfront treatment of advanced epithelial ovarian cancer.

PubMed

Lesnock, Jamie L; Farris, Coreen; Krivak, Thomas C; Smith, Kenneth J; Markman, Maurie

2011-09-01

Randomized trials have demonstrated significant improvements in progression-free survival (PFS) with consolidation paclitaxel (P) and bevacizumab (B) following cytoreduction and adjuvant carboplatin/paclitaxel (CP) for advanced epithelial ovarian cancer (EOC). We sought to evaluate the cost-effectiveness (C/E) of these consolidation strategies. A decision model was developed based on Gynecologic Oncology Group (GOG) protocols #178 and #218. Arm 1 is 6 cycles of CP. Arm 2 is 6 cycles of CP followed by 12 cycles of P (CP+P). Arm 3 is 1 cycle of CP, 5 cycles of CPB, and 16 cycles of B (CPB+B). Parameters include PFS, overall survival (OS), cost, complications (neuropathy for P and bowel perforation for B), and quality-of-life utility values. Sensitivity analyses were performed. The incremental cost-effectiveness ratio (ICER) for CT+T is $13,402/quality adjusted life year (QALY) gained compared to CP. For CPB+B compared to CP, the ICER is $326,530/QALY. When compared simultaneously, CPB+B is dominated, i.e. is more costly and less effective than CP+P. Results were robust to parameter variation. At a willingness to pay threshold of $100,000/QALY, CP+P was the preferred option throughout most of the decision space. Sensitivity analyses suggest that CPB+B would become the preferred option if it were to improve OS by 6.1 years over CP+P. In this model, B consolidation for advanced EOC was associated with a modest improvement in effectiveness that is less than that with P consolidation and more costly. A statistically significant improvement in survival may improve the value of B consolidation. Copyright © 2011 Elsevier Inc. All rights reserved.

Diagnostic value of 18F-FDG-PET/CT for the follow-up and restaging of soft tissue sarcomas in adults.

PubMed

Kassem, T W; Abdelaziz, O; Emad-Eldin, S

2017-10-01

The purpose of this study was to evaluate the clinical utility of 2-[ 18 F] fluoro-2-deoxy-D-glucose ( 18 FDG) positron emission tomography (PET)/computed tomography (CT) ( 18 F-FDG-PET/CT) in the follow-up of adult patients with soft tissue sarcomas. We prospectively evaluated 37 consecutive patients with known soft tissue sarcoma with 18 F-FDG-PET/CT examination for suspected recurrence of disease. They were 21 men and 16 women with a mean age of 49.6±10.6 (SD) years (range, 34-75years). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 18 F-FDG-PET/CT examination were calculated on a per patient basis. 18 F-FDG-PET/CT showed an overall diagnostic accuracy of 91.8%, sensitivity of 90% and a specificity of 100%. The positive predictive value and negative predictive value were 100 and 70%, respectively. The 18 F-FDG-PET/CT interpretations were correct in 34/37 patients (91.8%). Incorrect interpretations occurred in three patients (8.1%). Reasons for false negative findings were low 18 F-FDG uptake of local recurrence in one patient and low 18 F-FDG uptake of subcentimetric inguinal lymph node metastases. 18 F-FDG-PET/CT has a high diagnostic value in the follow-up of patients with soft tissue sarcoma. Copyright © 2017 Editions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

Our transthoracic biopsy practices accompanied by the imaging process: The contribution of positron emission tomography usage to accurate diagnosis.

PubMed

İntepe, Yavuz Selim; Metin, Bayram; Şahin, Sevinç; Kaya, Buğra; Okur, Aylin

2016-08-01

The objective of this study was to compare the results of transthoracic biopsies performed through the use of FDG PET/CT imaging with the results of transthoracic needle biopsy performed without using the FDG PET/CT imaging. The medical files of a total of 58 patients with pulmonary and mediastinal masses. A total of 20 patients, who were suspected of malignancy with the SUVmax value of over 2.5 in FDG PET/CT, underwent a biopsy process. Twelve patients with no suspicion of malignancy in accordance with CT images and with the SUVmax value below 2.5 underwent no biopsy procedure, and hence, they were excluded from the study. On the other hand, 26 patients directly went through a biopsy process with the suspicion of malignancy according to CT imaging, regardless of performing any FDG PET/CT imaging. According to the biopsy results, the number of the patients diagnosed with cancer was 20 (43.5%), while the number of non-cancerous patients was 26 (56.5%). When these findings were considered, it was determined that the sensitivity of the whole TTNB (transthoracic needle biopsy) was 80.8%, and the specificity was found as 100%. The positive predictive value of the whole TTNB was 100%, while its negative predictive value was found to be 80%. The sensitivity in TTNB performed together with FDG PET/CT was 90.9%, whereas the specificity was 100%. The positive predictive value of TTNB with FDG PET/CT was 100%, while its negative predictive value was found to be 81.8%. The sensitivity in TTNB performed without the use of FDG PET/CT was 73.3%, whereas the specificity was determined as 100%. Performing FDG PET/CT imaging process prior to a transthoracic biopsy as well as preferring FDG PET/CT for the spot on which the biopsy will be performed during the transthoracic biopsy procedure increases the rate of receiving accurate diagnosis.

A Method for the Automatic Exposure Control in Pediatric Abdominal CT: Application to the Standard Deviation Value and Tube Current Methods by Using Patient's Age and Body Size.

PubMed

Furuya, Ken; Akiyama, Shinji; Nambu, Atushi; Suzuki, Yutaka; Hasebe, Yuusuke

2017-01-01

We aimed to apply the pediatric abdominal CT protocol of Donnelly et al. in the United States to the pediatric abdominal CT-AEC. Examining CT images of 100 children, we found that the sectional area of the hepatic portal region (y) was strongly correlated with the body weight (x) as follows: y=7.14x + 84.39 (correlation coefficient=0.9574). We scanned an elliptical cone phantom that simulates the human body using a pediatric abdominal CT scanning method of Donnelly et al. in, and measured SD values. We further scanned the same phantom under the settings for adult CT-AEC scan and obtained the relationship between the sectional areas (y) and the SD values. Using these results, we obtained the following preset noise factors for CT-AEC at each body weight range: 6.90 at 4.5-8.9 kg, 8.40 at 9.0-17.9 kg, 8.68 at 18.0-26.9 kg, 9.89 at 27.0-35.9 kg, 12.22 at 36.0-45.0 kg, 13.52 at 45.1-70.0 kg, 15.29 at more than 70 kg. From the relation between age, weight and the distance of liver and tuber ischiadicum of 500 children, we obtained the CTDI vol values and DLP values under the scanning protocol of Donnelly et al. Almost all of DRL from these values turned out to be smaller than the DRL data of IAEA and various countries. Thus, by setting the maximum current values of CT-AEC to be the Donnelly et al.'s age-wise current values, and using our weight-wise noise factors, we think we can perform pediatric abdominal CT-AEC scans that are consistent with the same radiation safety and the image quality as those proposed by Donnelly et al.

Evaluation of dosimetry and image of very low-dose computed tomography attenuation correction for pediatric positron emission tomography/computed tomography: phantom study

NASA Astrophysics Data System (ADS)

Bahn, Y. K.; Park, H. H.; Lee, C. H.; Kim, H. S.; Lyu, K. Y.; Dong, K. R.; Chung, W. K.; Cho, J. H.

2014-04-01

In this study, phantom was used to evaluate attenuation correction computed tomography (CT) dose and image in case of pediatric positron emission tomography (PET)/CT scan. Three PET/CT scanners were used along with acryl phantom in the size for infant and ion-chamber dosimeter. The CT image acquisition conditions were changed from 10 to 20, 40, 80, 100 and 160 mA and from 80 to 100, 120 and 140 kVp, which aimed at evaluating penetrate dose and computed tomography dose indexvolume (CTDIvol) value. And NEMA PET Phantom™ was used to obtain PET image under the same CT conditions in order to evaluate each attenuation-corrected PET image based on standard uptake value (SUV) value and signal-to-noise ratio (SNR). In general, the penetrate dose was reduced by around 92% under the minimum CT conditions (80 kVp and 10 mA) with the decrease in CTDIvol value by around 88%, compared with the pediatric abdomen CT conditions (100 kVp and 100 mA). The PET image with its attenuation corrected according to each CT condition showed no change in SUV value and no influence on the SNR. In conclusion, if the minimum dose CT that is properly applied to body of pediatric patient is corrected for attenuation to ensure that the effective dose is reduced by around 90% or more compared with that for adult patient, this will be useful to reduce radiation exposure level.

Effects of self-paced interval and continuous training on health markers in women.

PubMed

Connolly, Luke J; Bailey, Stephen J; Krustrup, Peter; Fulford, Jonathan; Smietanka, Chris; Jones, Andrew M

2017-11-01

To compare the effects of self-paced high-intensity interval and continuous cycle training on health markers in premenopausal women. Forty-five inactive females were randomised to a high-intensity interval training (HIIT; n = 15), continuous training (CT; n = 15) or an inactive control (CON; n = 15) group. HIIT performed 5 × 5 min sets comprising repetitions of 30-s low-, 20-s moderate- and 10-s high-intensity cycling with 2 min rest between sets. CT completed 50 min of continuous cycling. Training was completed self-paced, 3 times weekly for 12 weeks. Peak oxygen uptake (16 ± 8 and 21 ± 12%), resting heart rate (HR) (-5 ± 9 and -4 ± 7 bpm) and visual and verbal learning improved following HIIT and CT compared to CON (P < 0.05). Total body mass (-0.7 ± 1.4 kg), submaximal walking HR (-3 ± 4 bpm) and verbal memory were enhanced following HIIT (P < 0.05), whereas mental well-being, systolic (-5 ± 6 mmHg) and mean arterial (-3 ± 5 mmHg) blood pressures were improved following CT (P < 0.05). Participants reported similar levels of enjoyment following HIIT and CT, and there were no changes in fasting serum lipids, fasting blood [glucose] or [glucose] during an oral glucose tolerance test following either HIIT or CT (P > 0.05). No outcome variable changed in the CON group (P > 0.05). Twelve weeks of self-paced HIIT and CT were similarly effective at improving cardiorespiratory fitness, resting HR and cognitive function in inactive premenopausal women, whereas blood pressure, submaximal HR, well-being and body mass adaptations were training-type-specific. Both training methods improved established health markers, but the adaptations to HIIT were evoked for a lower time commitment.

[Decision process of Notification Value by the Dose Index Registry system in X-ray computed tomography].

PubMed

Shinozaki, Masafumi; Muramatsu, Yoshihisa; Sasaki, Toru

2014-01-01

A new technical standard for X-ray computed tomography (CT) has been published by the National Electrical Manufacturers Association (NEMA) that allows the Alert Value and Notification Value for cumulative dose to be configurable by CT systems operators in conjunction with the XR-25 (Dose check) standard. In this study, a decision method of the Notification Values for reducing the radiation dose was examined using the dose index registry (DIR) system, during 122 continuous days from August 1, 2012 to November 30, 2012. CT images were obtained using the Discovery CT 750HD (GE Healthcare) and the dose index was calculated using the DoseWatch DIR system. The CT dose index-volume (CTDIvol) and dose-length product (DLP) were output from the DIR system in comma-separated value (CSV) file format for each examination protocol. All data were shown as a schematic boxplot using statistical processing software. The CTDIvol of a routine chest examination showed the following values (maximum: 23.84 mGy; minimum: 2.55 mGy; median: 7.60 mGy; 75% tile: 10.01 mGy; 25% tile: 6.54 mGy). DLP showed the following values (maximum: 944.56 mGy·cm; minimum: 97.25 mGy·cm; median: 307.35 mGy·cm; 75% tile: 406.87 mGy·cm; 25% tile: 255.75 mGy·cm). These results indicate that the 75% tile of CTDIvol and DLP as an initial value proved to be safe and efficient for CT examination and operation. We have thus established one way of determining the Notification Value from the output of the DIR system. Transfer back to the protocol of the CT and automated processing each numeric value in the DIR system is desired.

TU-H-207A-03: CT Hounsfield Unit Accuracy: Effect of Beam Hardening On Phantom and Clinical Whole-Body CT Images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ai, H; Wendt, R

2016-06-15

Purpose: To assess the effect of beam hardening on measured CT HU values. Methods: An anthropomorphic knee phantom was scanned with the CT component of a GE Discovery 690 PET/CT scanner (120kVp, 300mAs, 40?0.625mm collimation, pitch=0.984, FOV=500mm, matrix=512?512) with four different scan setups, each of which induces different degrees of beam hardening by introducing additional attenuation media into the field of view. Homogeneous voxels representing “soft tissue” and “bone” were segmented by HU thresholding followed by a 3D morphological erosion operation which removes the non-homogenous voxels located on the interface of thresholded tissue mask. HU values of segmented “soft tissue”more » and “bone” were compared.Additionally, whole-body CT data with coverage from the skull apex to the end of toes were retrospectively retrieved from seven PET/CT exams to evaluate the effect of beam hardening in vivo. Homogeneous bone voxels were segmented with the same method previously described. Total In-Slice Attenuation (TISA) for each CT slice, defined as the summation of HU values over all voxels within a CT slice, was calculated for all slices of the seven whole-body CT datasets and evaluated against the mean HU values of homogeneous bone voxels within that slice. Results: HU values measured from the phantom showed that while “soft tissue” HU values were unaffected, added attenuation within the FOV caused noticeable decreases in the measured HU values of “bone” voxels. A linear relationship was observed between bone HU and TISA for slices of the torso and legs, but not of the skull. Conclusion: Beam hardening effect is not an issue of concern for voxels with HU in the soft tissue range, but should not be neglected for bone voxels. A linear relationship exists between bone HU and the associated TISA in non-skull CT slices, which can be exploited to develop a correction strategy.« less

Component extraction on CT volumes of assembled products using geometric template matching

NASA Astrophysics Data System (ADS)

Muramatsu, Katsutoshi; Ohtake, Yutaka; Suzuki, Hiromasa; Nagai, Yukie

2017-03-01

As a method of non-destructive internal inspection, X-ray computed tomography (CT) is used not only in medical applications but also for product inspection. Some assembled products can be divided into separate components based on density, which is known to be approximately proportional to CT values. However, components whose densities are similar cannot be distinguished using the CT value driven approach. In this study, we proposed a new component extraction algorithm from the CT volume, using a set of voxels with an assigned CT value with the surface mesh as the template rather than the density. The method has two main stages: rough matching and fine matching. At the rough matching stage, the position of candidate targets is identified roughly from the CT volume, using the template of the target component. At the fine matching stage, these candidates are precisely matched with the templates, allowing the correct position of the components to be detected from the CT volume. The results of two computational experiments showed that the proposed algorithm is able to extract components with similar density within the assembled products on CT volumes.

Relationship between Hounsfield unit in CT scan and gray scale in CBCT

NASA Astrophysics Data System (ADS)

Kamaruddin, Noorshaida; Rajion, Zainul Ahmad; Yusof, Asilah; Aziz, Mohd Ezane

2016-12-01

Cone-beam computed tomography (CBCT) is an imaging system which has advantages over computed tomography (CT). Recently, CBCT has become widely used for oral and maxillofacial imaging. In CT scan, Hounsfield Unit (HU) is proportional to the degree of x-ray attenuation by the tissue. In CBCT, the degree of x-ray attenuation is shown by gray scale (voxel value). The aim of the present (in vitro) study was to investigate the relationship between gray scale in CBCT and HU in CT scan. In this descriptive study, the anthropomorphic head phantom was scanned with CBCT and CT scanner. Gray scales and HUs were detected on images at the crown of the teeth, trabecular and cortical bone of mandible. The images were analyzed to obtain the gray scale value and HU value. The obtained value then used to investigate the relationship between CBCT gray scales and HUs. For the statistical analysis, t-test, Pearson's correlation and regression analysis were used. The differences between the gray scale of CBCT and HU of CT were statistically not significant, whereas the Pearson's correlation coefficients demonstrated a statistically significant correlation between gray scale of CBCT and HU of CT values. Considering the fact that gray scale in CBCT is important in pre assessment evaluation of bone density before implant treatments, it is recommended because of the lower dose and cost compared to CT scan.

Value of apparent diffusion coefficient (ADC) in assessing radiotherapy and chemotherapy success in cervical cancer.

PubMed

Fu, Zhan-Zhao; Peng, Yong; Cao, Li-Yan; Chen, Yan-Sheng; Li, Kun; Fu, Bao-Hong

2015-06-01

We investigated the clinical significance of apparent diffusion coefficient (ADC) values in diffusion-weighted magnetic resonance imaging (DWI) in monitoring the efficacy of radiotherapy (RT) and chemotherapy (CT) treatments in cervical cancer. In order to identify relevant high quality clinical cohort studies reporting the use of DWI in cervical cancers, the following electronic databases in English and Chinese languages were comprehensively searched: MEDLINE, Science Citation Index database, Cochrane Library Database, PubMed, Embase, CINAHL, and Current Contents Index; Chinese Biomedical Database, Chinese Journal Full-Text Database. All selected studies were published prior to March 2014, and data extracted from these studies were analyzed using STATA 12.0 statistical software. We initially retrieved 196 articles (79 Chinese articles and 117 English articles) through database searches and finally selected sixteen cohort studies for this meta-analysis. The 16 studies contained a combined total of 517 subjects, and all selected studies reported the mean ADC value (10(-3) mm(2)/s) in DWI in cervical cancer patients treated with RT and CT. Combined standardized mean difference (SMD) suggested that the mean post-RT and mean post-CT ADC values were significantly higher than the mean pre-RT and mean pre-CT ADC values, respectively, in cervical cancer patients (SMD=2.95, 95% CI=2.19-3.72, P<0.001). Ethnicity-stratified analysis revealed that increased ADC values were observed post-RT and post-CT in both Caucasian (SMD=1.44, 95% CI=0.93-1.95, P<0.001) and Asian populations (SMD=3.32, 95% CI=2.42-4.22, P<0.001), compared with the mean ADC values before RT and CT, respectively, in the two subgroups. Further, subgroup analysis based on b-value revealed that higher ADC values were found in cervical cancer patients after RT and CT, compared to before RT and CT treatment, with both b value≤900 (SMD=3.71, 95% CI=2.35-5.07, P<0.001) and >900 (SMD=2.55, 95% CI=1.78-3.32, P<0.001). The mean ADC value in patients without residual tumor post-RT and post-CT treatment was significantly higher than seen in patients with residual tumors (SMD=0.80, 95% CI=0.49-1.12, P<0.001). Our meta-analysis revealed a significant correlation between mean ADC values and the clinical response to RT and CT treatment. Thus, ADC values in DWI may be effective in evaluating the clinical outcome of treatments in cervical cancer patients. Copyright © 2015 Elsevier Inc. All rights reserved.

Assessment of fluid distribution and flow properties in two phase fluid flow using X-ray CT technology

NASA Astrophysics Data System (ADS)

Jiang, Lanlan; Wu, Bohao; Li, Xingbo; Wang, Sijia; Wang, Dayong; Zhou, Xinhuan; Zhang, Yi

2018-04-01

To study on microscale distribution of CO2 and brine during two-phase flow is crucial for understanding the trapping mechanisms of CO2 storage. In this study, CO2-brine flow experiments in porous media were conducted using X-ray computed tomography. The porous media were packed with glass beads. The pore structure (porosity/tortuosity) and flow properties at different flow rates and flow fractions were investigated. The results showed that porosity of the packed beads differed at different position as a result of heterogeneity. The CO2 saturation is higher at low injection flow rates and high CO2 fractions. CO2 distribution at the pore scale was also visualized. ∅ Porosity of porous media CT brine_ sat grey value of sample saturated with brine CT dry grey value of sample saturated with air CT brine grey value of pure brine CT air grey value of pure air CT flow grey values of sample with two fluids occupying the pore space {CT}_{CO_2_ sat} grey value of sample saturated with CO2 {f}_{CO_2}({S}_{CO_2}) CO2 fraction {q}_{CO_2} the volume flow rate for CO2 q brine the volume flow rate for brine L Thickness of the porous media, mm L e a bundle of capillaries of equal length, mm τ Tortuosity, calculated from L e / L.

Diagnostic value of CT, PET and combined PET/CT performed with low-dose unenhanced CT and full-dose enhanced CT in the initial staging of lymphoma.

PubMed

Pinilla, I; Gómez-León, N; Del Campo-Del Val, L; Hernandez-Maraver, D; Rodríguez-Vigil, B; Jover-Díaz, R; Coya, J

2011-10-01

The aim of this paper was to compare the accuracy of contrast-enhanced computed tomography (CT), positron emission tomography (PET), unenhanced low-dose PET/CT (LD-PET/CT) and full-dose enhanced PET/CT (FD-PET/CT) for the initial staging of lymphoma. One hundred and one lymphoma patients were examined by [18F]FDG-PET/CT including unenhanced low-dose CT and enhanced full-dose CT. Each modality of PET/CT was evaluated by a nuclear medicine physician and a radiologist unaware of the other modality, while the CT and PET images were interpreted separately by another independent radiologist and nuclear medicine physician respectively. The nodal and extranodal lesions detected by each technique were compared with a reference standard. For nodal assessment, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+), and negative LR (LR-) of LD-PET/CT were 97%, 96%, 98%, 95%, 26 and 0.02 respectively, and those of FD-PET/CT were 97%, 97%, 98%, 95%, 36 and 0.02. These results were significantly better than those of PET (sensitivity 82%, specificity 81%, PPV 88%, NPV 72%, LR+ 4.3, LR- 0.21). Likewise, both PET/CT displayed a higher sensitivity, NPV and LR- than CT (91%, 84%, 0.1 respectively). For organ evaluation, both modalities of PET/CT also had significantly better sensitivity and NPV than that of PET (LD-PET/CT: sensitivity 92%, NPV 90%; FD-PET/CT sensitivity 94%, NPV 92%; PET: sensitivity 70%, NPV 69%). The sensitivity, specificity, PPV and NPV for bone marrow involvement were 29%, 84%, 45% and 72% respectively for PET, and 29%, 90%, 56%, and 74% for both, LD-PET/CT, and FD-PET/CT. No significant differences were found between LD-PET/CT and FD-PET/CT, but FD-PET/CT detected important incidental findings in 5.9% of patients. PET/CT is an accurate technique for the initial staging of lymphomas without significant differences between LD-PET/CT and FD-PET/CT. FD-PET/CT detects relevant incidental findings that are missed on LD-PET/CT.

Analyzing radiation absorption difference of dental substance by using Dual CT

NASA Astrophysics Data System (ADS)

Yu, H.; Lee, H. K.; Cho, J. H.; Yang, H. J.; Ju, Y. S.

2015-07-01

The purpose of this study was to evaluate the changes of noise and computer tomography (CT) number in each dental substance, by using the metal artefact reduction algorithm; we used dual CT for this study. For the study, we produced resin, titanium, gypsum, and wax that are widely used by dentists. In addition, we made nickel to increase the artefact. While making the study materials, we made sure that there is no difficulty when inserting the substances inside phantom. In order to study, we scanned before and after using the metal artefact reduction algorithm. We conducted an average analysis of CT number and noise, before and after using the metal artefact reduction algorithm. As a result, there was no difference in CT number and noise before and after using the metal artefact reduction algorithm. However, when it comes to the noise value in each substance, wax's noise value was the lowest whereas titanium's noise value was the highest, after applying the metal artefact reduction algorithm. In nickel, CT number and noise value from artefact area showed a decreased noise value when applying the metal artefact reduction algorithm. In conclusion, we assumed that we could increase the effectiveness of CT examination by applying dual energy's metal artefact reduction algorithm.

[The Clinical Application of Video Mediastinoscopy and CT in the N Staging of Preoperative Lung Cancer.].

PubMed

Wang, Zhiheng; Qi, Weibo; Zhu, Yong; Lin, Ruobai

2009-10-20

Preoperative lung cancer with mediastinal lymph nodes metastasis can be diagnosed by vedio mediastinoscopy (VM) and CT. This study was to explore the value of VM and CT in the diagnosis of N staging of preoperative lung cancer, and to discuss the difference between the two methods. Forty-eight cases diagnosed of lung cancer by CT or PET-CT were examined by VM. The sensitivity, specificity, validity, positive predictive value and negative predictive value of VM and CT were speculated according to the postoperative pathological reports, and the difference between VM and CT in the diagnosis of lung cancer with mediastinal lymph nodes metastasis was discussed. (1)Under the examination of VM, 31 patients with the negative outcome received the direct operation; 14 patients with N2 received 2 courses of neoadjuvant chemotherapy before operation; 3 patients with N3 received chemotherapy and/or radiotherapy. (2)Forty-one cases with final diagnosis of lung cancer were used as samples to speculate the sensitivity, specificity, validity, positive predictive value and negative predictive value of VM. They were 93.3%, 100%, 97.6%, 100%, 96.3%, which of CT were 66.7%, 53.8%, 58.5%, 45.5%, 73.7% (Chi-square=4.083, P=0.039), the difference between VM and CT was statistically significant. (3)In this group, the complications of VM incidence rate was 2.08% (1/48), and the case was pneumothorax. VM is superior to CT in the diagnosis of N staging of preoperative lung cancer; Due to its safety and effectiveness, VM will be wildly used in the field of thoracic surgery.

Concomitant chemoradiotherapy versus induction docetaxel, cisplatin and 5 fluorouracil (TPF) followed by concomitant chemoradiotherapy in locally advanced head and neck cancer: a phase II randomized study.

PubMed

Paccagnella, A; Ghi, M G; Loreggian, L; Buffoli, A; Koussis, H; Mione, C A; Bonetti, A; Campostrini, F; Gardani, G; Ardizzoia, A; Dondi, D; Guaraldi, M; Cavallo, R; Tomio, L; Gava, A

2010-07-01

Concomitant chemoradiotherapy (CT/RT) is the standard treatment of locally advanced squamous cell carcinoma of the head and neck (SCCHN). We evaluated the efficacy of induction docetaxel (Taxotere), cisplatin, and 5-fluorouracil (TPF) before CT/RT versus CT/RT alone. Patients with stage III-IVM0 SCCHN, Eastern Cooperative Oncology Group performance status of zero to one, were randomly assigned to receive CT/RT alone (arm A: two cycles of cisplatin 20 mg/m(2), days1-4, plus 5-fluorouracil 800 mg/m(2)/day 96 h continuous infusion, during weeks 1 and 6 of radiotherapy) or three cycles of TPF (arm B: docetaxel 75 mg/m(2) and cisplatin 80 mg/m(2), day 1, and 5-fluorouracil 800 mg/m(2)/day 96 h continuous infusion, every 3 weeks) followed by the same CT/RT. The primary end point was the rate of radiologic complete response (CR) at 6-8 weeks after the end of CT/RT. A total of 101 patients were randomly allocated to the study (51 arm A; 50 arm B). CR rates were 21.2% (arm A) versus 50% (arm B). Median progression-free survival and overall survival were, respectively, 19.7 and 33.3 months (arm A) and 30.4 and 39.6 months (arm B). Hematologic and non-hematologic toxic effects during CT/RT were similar in the two arms. Induction TPF followed by CT/RT was associated with higher radiologic CR in patients with locally advanced SCCHN with no negative impact on CT/RT feasibility.

Clinical outcome of patients with early stage favorable Hodgkin lymphoma treated with ABVD × two cycles followed by FDG-PET/CT restaging and 20 Gy of involved-site radiotherapy.

PubMed

Kamran, Sophia C; Jacene, Heather A; Chen, Yu-Hui; Mauch, Peter M; Ng, Andrea K

2018-06-01

Our purpose was to assess outcome of patients with early-stage, favorable (per GHSG criteria) Hodgkin Lymphoma (HL) staged with FDG-PET/CT and treated with two cycles of adriamycin, bleomycin, vincristine, and dacarbazine (ABVD) followed by PET/CT assessment and involved-site radiotherapy (ISRT) to 20 Gy. Records of 23 patients who met eligibility criteria, treated between 2008 and 2016, were reviewed. PET response after two cycles of ABVD was independently assessed by a nuclear medicine physician. After two cycles of ABVD, 91.3% of patients had a Deauville score of 1-2; 1 patient had a score of 3. Median follow-up was 45.3 months. As of this analysis, all patients are alive without disease. One patient had an out-of-field relapse, yielding a 4-year relapse-free survival rate of 92.9% (95%CI [59.1, 99.0]). Our results showed that with careful patient selection by initial disease characteristics and FDG-PET response to chemotherapy, the use of a more restricted treatment volume of ISRT to 20 Gy following ABVD × 2 is associated with excellent outcomes.

Assessment of benefits of conservation agriculture on soil functions in arable production systems in Europe

USDA-ARS?s Scientific Manuscript database

Conventional tillage (CT), with reduced alternatives in crop rotation (monocropping), is the norm in European farming. CT may cause adverse effects on some of the five major soil functions, viz. primary productivity, carbon sequestration and regulation, nutrient cycling and provision, water regulati...

Multi-energy spectral CT: adding value in emergency body imaging.

PubMed

Punjabi, Gopal V

2018-04-01

Most vendors offer scanners capable of dual- or multi-energy computed tomography (CT) imaging. Advantages of multi-energy CT scanning include superior tissue characterization, detection of subtle iodine uptake differences, and opportunities to reduce contrast dose. However, utilization of this technology in the emergency department (ED) remains low. The purpose of this pictorial essay is to illustrate the value of multi-energy CT scanning in emergency body imaging.

4D-CT Lung registration using anatomy-based multi-level multi-resolution optical flow analysis and thin-plate splines.

PubMed

Min, Yugang; Neylon, John; Shah, Amish; Meeks, Sanford; Lee, Percy; Kupelian, Patrick; Santhanam, Anand P

2014-09-01

The accuracy of 4D-CT registration is limited by inconsistent Hounsfield unit (HU) values in the 4D-CT data from one respiratory phase to another and lower image contrast for lung substructures. This paper presents an optical flow and thin-plate spline (TPS)-based 4D-CT registration method to account for these limitations. The use of unified HU values on multiple anatomy levels (e.g., the lung contour, blood vessels, and parenchyma) accounts for registration errors by inconsistent landmark HU value. While 3D multi-resolution optical flow analysis registers each anatomical level, TPS is employed for propagating the results from one anatomical level to another ultimately leading to the 4D-CT registration. 4D-CT registration was validated using target registration error (TRE), inverse consistency error (ICE) metrics, and a statistical image comparison using Gamma criteria of 1 % intensity difference in 2 mm(3) window range. Validation results showed that the proposed method was able to register CT lung datasets with TRE and ICE values <3 mm. In addition, the average number of voxel that failed the Gamma criteria was <3 %, which supports the clinical applicability of the propose registration mechanism. The proposed 4D-CT registration computes the volumetric lung deformations within clinically viable accuracy.

The diagnostic performance and added value of (18)F-FDG PET/CT in the detection of liver metastases in recurrent colorectal carcinoma patients.

PubMed

Odalovic, Strahinja; Artiko, Vera; Sobic-Saranovic, Dragana; Stojiljkovic, Milica; Petrovic, Milorad; Petrovic, Nebojsa; Kozarevic, Nebojsa; Grozdic-Milojevic, Isidora; Obradovic, Vladimir

2015-01-01

The aim of this study was to assess the value of (18)F-fluorodeoxyglucose ((18)F-FDG) PET/CT in detection of liver metastases in patients with suspected recurrent colorectal carcinoma, as well as to compare diagnostic performance of (18)F-FDG PET/CT with conventional imaging methods (MDCT). This study included 73 patients with resected primary colorectal adenocarcinoma referred for (18)F-FDG PET/CT to the National PET Center, at the Clinical Center of Serbia, Belgrade, from January 2010 to May 2013, with suspicion of recurrence. The patients underwent (18)F-FDG PET/CT examination on a 64-slice hybrid PET/CT scanner (Biograph, TruePoint64, Siemens Medical Solutions, Inc. USA). Prior to (18)F-FDG PET/CT all patients underwent contrast-enhanced MDCT. Findings of (18)F-FDG PET/CT and MDCT were compared to findings of subsequent histopathological examinations or with results of clinical and imaging follow-up over at least six months. Final diagnosis of liver metastases of colorectal cancer was made either by histopathological examination of specimen after biopsy or surgery, or based on clinical, laboratory and imaging evaluation during first six months after PET/CT scan. In detection of liver metastases (18)F-FDG PET/CT showed sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 83.3%, 95.3%, 92.6%, 89.1% and 90.4%, respectively. In addition, MDCT showed sensitivity, specificity, positive predictive value, negative predictive value and accuracy in detection of liver metastases of 60%, 88.4%, 78.3%, 76% and 76.7%, respectively. There was significant difference in sensitivity (83.3% vs 60%; P=0.045) between these two methods. In addition, significant difference was observed in accuracy between PET/CT and MDCT (90.4% vs 76.7%; P=0.016). The higher specificity in visualization of liver metastases was also achieved by (18)F-FDG PET/CT compared to MDCT (95.3% vs 88.4%), but this difference was not significant (P=0.37). (18)F-FDG PET/CT was highly sensitive, specific and accurate method in detection of liver metastases in patients with suspected recurrent colorectal carcinoma in our study. This hybrid imaging showed superior diagnostic performance in evaluation of suspected colorectal cancer liver metastases compared to conventional imaging.

Advanced non-contrasted computed tomography post-processing by CT-Calculometry (CT-CM) outperforms established predictors for the outcome of shock wave lithotripsy.

PubMed

Langenauer, J; Betschart, P; Hechelhammer, L; Güsewell, S; Schmid, H P; Engeler, D S; Abt, D; Zumstein, V

2018-05-29

To evaluate the predictive value of advanced non-contrasted computed tomography (NCCT) post-processing using novel CT-calculometry (CT-CM) parameters compared to established predictors of success of shock wave lithotripsy (SWL) for urinary calculi. NCCT post-processing was retrospectively performed in 312 patients suffering from upper tract urinary calculi who were treated by SWL. Established predictors such as skin to stone distance, body mass index, stone diameter or mean stone attenuation values were assessed. Precise stone size and shape metrics, 3-D greyscale measurements and homogeneity parameters such as skewness and kurtosis, were analysed using CT-CM. Predictive values for SWL outcome were analysed using logistic regression and receiver operating characteristics (ROC) statistics. Overall success rate (stone disintegration and no re-intervention needed) of SWL was 59% (184 patients). CT-CM metrics mainly outperformed established predictors. According to ROC analyses, stone volume and surface area performed better than established stone diameter, mean 3D attenuation value was a stronger predictor than established mean attenuation value, and parameters skewness and kurtosis performed better than recently emerged variation coefficient of stone density. Moreover, prediction of SWL outcome with 80% probability to be correct would be possible in a clearly higher number of patients (up to fivefold) using CT-CM-derived parameters. Advanced NCCT post-processing by CT-CM provides novel parameters that seem to outperform established predictors of SWL response. Implementation of these parameters into clinical routine might reduce SWL failure rates.

Clinical impact of 18 F-FDG positron emission tomography/CT on adenoid cystic carcinoma of the head and neck.

PubMed

Jung, Ji-Hoon; Lee, Sang-Woo; Son, Seung Hyun; Kim, Choon-Young; Lee, Chang-Hee; Jeong, Ju Hye; Jeong, Shin Young; Ahn, Byeong-Cheol; Lee, Jaetae

2017-03-01

The purpose of this retrospective study was to assess the diagnostic value of 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT and the prognostic value of metabolic PET parameters in patients with adenoid cystic carcinoma of the head and neck (ACCHN). Forty patients with newly diagnosed ACCHN were enrolled in this study. We investigated the diagnostic value of 18 F-FDG PET/CT for detecting and staging compared to conventional CT. Kaplan-Meier survival analysis for progression-free survival (PFS) was performed with clinicopathological factors and metabolic PET parameters. The 18 F-FDG PET/CT showed comparable sensitivity (92.3%) to conventional CT for lesion detection, and changed staging and management plan in 6 patients (15.0%). Lower PFS rates were associated with advanced T classification, advanced TNM classification, high maximum standardized uptake value (SUVmax; >5.1), and high total lesion glycolysis (>40.1) of the primary tumor. The 18 F-FDG PET/CT can provide additional information for initial staging, and metabolic PET parameters may serve as prognostic factors of ACCHN. © 2016 Wiley Periodicals, Inc. Head Neck 39: 447-455, 2017. © 2016 Wiley Periodicals, Inc.

Collateral Ventilation to Congenital Hyperlucent Lung Lesions Assessed on Xenon-Enhanced Dynamic Dual-Energy CT: an Initial Experience

PubMed Central

Yang, Dong Hyun; Kim, Namkug; Park, Seung Il; Kim, Dong Kwan; Kim, Ellen Ai-Rhan

2011-01-01

Objective We wanted to evaluate the resistance to collateral ventilation in congenital hyperlucent lung lesions and to correlate that with the anatomic findings on xenon-enhanced dynamic dual-energy CT. Materials and Methods Xenon-enhanced dynamic dual-energy CT was successfully and safely performed in eight children (median age: 5.5 years, 4 boys and 4 girls) with congenital hyperlucent lung lesions. Functional assessment of the lung lesions on the xenon map was done, including performing a time-xenon value curve analysis and assessing the amplitude of xenon enhancement (A) value, the rate of xenon enhancement (K) value and the time of arrival value. Based on the A value, the lung lesions were categorized into high or low (A value > 10 Hounsfield unit [HU]) resistance to collateral ventilation. In addition, the morphologic CT findings of the lung lesions, including cyst, mucocele and an accessory or incomplete fissure, were assessed on the weighted-average CT images. The xenon-enhanced CT radiation dose was estimated. Results Five of the eight lung lesions were categorized into the high resistance group and three lesions were categorized into the low resistance group. The A and K values in the normal lung were higher than those in the low resistance group. The time of arrival values were delayed in the low resistance group. Cysts were identified in five lesions, mucocele in four, accessory fissure in three and incomplete fissure in two. Either cyst or an accessory fissure was seen in four of the five lesions showing high resistance to collateral ventilation. The xenon-enhanced CT radiation dose was 2.3 ± 0.6 mSv. Conclusion Xenon-enhanced dynamic dual-energy CT can help visualize and quantitate various degrees of collateral ventilation to congenital hyperlucent lung lesions in addition to assessing the anatomic details of the lung. PMID:21228937

Collateral ventilation to congenital hyperlucent lung lesions assessed on xenon-enhanced dynamic dual-energy CT: an initial experience.

PubMed

Goo, Hyun Woo; Yang, Dong Hyun; Kim, Namkug; Park, Seung Il; Kim, Dong Kwan; Kim, Ellen Ai-Rhan

2011-01-01

We wanted to evaluate the resistance to collateral ventilation in congenital hyperlucent lung lesions and to correlate that with the anatomic findings on xenon-enhanced dynamic dual-energy CT. Xenon-enhanced dynamic dual-energy CT was successfully and safely performed in eight children (median age: 5.5 years, 4 boys and 4 girls) with congenital hyperlucent lung lesions. Functional assessment of the lung lesions on the xenon map was done, including performing a time-xenon value curve analysis and assessing the amplitude of xenon enhancement (A) value, the rate of xenon enhancement (K) value and the time of arrival value. Based on the A value, the lung lesions were categorized into high or low (A value > 10 Hounsfield unit [HU]) resistance to collateral ventilation. In addition, the morphologic CT findings of the lung lesions, including cyst, mucocele and an accessory or incomplete fissure, were assessed on the weighted-average CT images. The xenon-enhanced CT radiation dose was estimated. Five of the eight lung lesions were categorized into the high resistance group and three lesions were categorized into the low resistance group. The A and K values in the normal lung were higher than those in the low resistance group. The time of arrival values were delayed in the low resistance group. Cysts were identified in five lesions, mucocele in four, accessory fissure in three and incomplete fissure in two. Either cyst or an accessory fissure was seen in four of the five lesions showing high resistance to collateral ventilation. The xenon-enhanced CT radiation dose was 2.3 ± 0.6 mSv. Xenon-enhanced dynamic dual-energy CT can help visualize and quantitate various degrees of collateral ventilation to congenital hyperlucent lung lesions in addition to assessing the anatomic details of the lung.

Chromosome Territories

PubMed Central

Cremer, Thomas; Cremer, Marion

2010-01-01

Chromosome territories (CTs) constitute a major feature of nuclear architecture. In a brief statement, the possible contribution of nuclear architecture studies to the field of epigenomics is considered, followed by a historical account of the CT concept and the final compelling experimental evidence of a territorial organization of chromosomes in all eukaryotes studied to date. Present knowledge of nonrandom CT arrangements, of the internal CT architecture, and of structural interactions with other CTs is provided as well as the dynamics of CT arrangements during cell cycle and postmitotic terminal differentiation. The article concludes with a discussion of open questions and new experimental strategies to answer them. PMID:20300217

PET attenuation coefficients from CT images: experimental evaluation of the transformation of CT into PET 511-keV attenuation coefficients.

PubMed

Burger, C; Goerres, G; Schoenes, S; Buck, A; Lonn, A H R; Von Schulthess, G K

2002-07-01

The CT data acquired in combined PET/CT studies provide a fast and essentially noiseless source for the correction of photon attenuation in PET emission data. To this end, the CT values relating to attenuation of photons in the range of 40-140 keV must be transformed into linear attenuation coefficients at the PET energy of 511 keV. As attenuation depends on photon energy and the absorbing material, an accurate theoretical relation cannot be devised. The transformation implemented in the Discovery LS PET/CT scanner (GE Medical Systems, Milwaukee, Wis.) uses a bilinear function based on the attenuation of water and cortical bone at the CT and PET energies. The purpose of this study was to compare this transformation with experimental CT values and corresponding PET attenuation coefficients. In 14 patients, quantitative PET attenuation maps were calculated from germanium-68 transmission scans, and resolution-matched CT images were generated. A total of 114 volumes of interest were defined and the average PET attenuation coefficients and CT values measured. From the CT values the predicted PET attenuation coefficients were calculated using the bilinear transformation. When the transformation was based on the narrow-beam attenuation coefficient of water at 511 keV (0.096 cm(-1)), the predicted attenuation coefficients were higher in soft tissue than the measured values. This bias was reduced by replacing 0.096 cm(-1) in the transformation by the linear attenuation coefficient of 0.093 cm(-1) obtained from germanium-68 transmission scans. An analysis of the corrected emission activities shows that the resulting transformation is essentially equivalent to the transmission-based attenuation correction for human tissue. For non-human material, however, it may assign inaccurate attenuation coefficients which will also affect the correction in neighbouring tissue.

Abbreviated injury scale scoring in traffic fatalities: comparison of computerized tomography and autopsy.

PubMed

Leth, Peter Mygind; Ibsen, Marlene

2010-06-01

The purpose of this investigation is to evaluate the value of postmortem computerized tomography (CT) for Abbreviated Injury Scale (AIS) scoring and Injury Severity Scoring (ISS) of traffic fatalities. This is a prospective investigation of a consecutive series of 52 traffic fatalities from Southern Denmark that were CT scanned and autopsied. The AIS and ISS scores based on CT and autopsy (AU) were registered in a computer database and compared. Kappa values for reproducibility of AIS-severity scores and ISS scores were calculated. On an average, there was a 94% agreement between AU and CT in detecting the presence or absence of lesions in the various anatomic regions, and the severity scores were the same in 90% of all cases (range, 75-100%). When different severity scoring was obtained, CT detected more lesions with a high severity score in the facial skeleton, pelvis, and extremities, whereas AU detected more lesions with high scores in the soft tissues (especially in the aorta), cranium, and ribs. The kappa value for reproducibility of AIS scores confirmed that the agreement between the two methods was good. The lowest kappa values (>0.6) were found for the facial skeleton, cerebellum, meninges, neck organs, lungs, kidneys, and gastrointestinal tract. In these areas, the kappa value provided moderate agreement between CT and AU. For all other areas, there was a substantial agreement between the two methods. The ISS scores obtained by CT and by AU were calculated and were found to be with no or moderate variation in 85%. Rupture of the aorta was often overlooked by CT, resulting in too low ISS scoring. The most precise postmortem AIS and ISS scorings of traffic fatalities was obtained by a combination of AU and CT. If it is not possible to perform an AU, then CT may be used as an acceptable alternative for AIS scoring. We have identified one important obstacle for postmortem ISS scoring, namely that aorta ruptures are not easily detected by post mortem CT.

Technical Note: FreeCT_wFBP: A robust, efficient, open-source implementation of weighted filtered backprojection for helical, fan-beam CT.

PubMed

Hoffman, John; Young, Stefano; Noo, Frédéric; McNitt-Gray, Michael

2016-03-01

With growing interest in quantitative imaging, radiomics, and CAD using CT imaging, the need to explore the impacts of acquisition and reconstruction parameters has grown. This usually requires extensive access to the scanner on which the data were acquired and its workflow is not designed for large-scale reconstruction projects. Therefore, the authors have developed a freely available, open-source software package implementing a common reconstruction method, weighted filtered backprojection (wFBP), for helical fan-beam CT applications. FreeCT_wFBP is a low-dependency, GPU-based reconstruction program utilizing c for the host code and Nvidia CUDA C for GPU code. The software is capable of reconstructing helical scans acquired with arbitrary pitch-values, and sampling techniques such as flying focal spots and a quarter-detector offset. In this work, the software has been described and evaluated for reconstruction speed, image quality, and accuracy. Speed was evaluated based on acquisitions of the ACR CT accreditation phantom under four different flying focal spot configurations. Image quality was assessed using the same phantom by evaluating CT number accuracy, uniformity, and contrast to noise ratio (CNR). Finally, reconstructed mass-attenuation coefficient accuracy was evaluated using a simulated scan of a FORBILD thorax phantom and comparing reconstructed values to the known phantom values. The average reconstruction time evaluated under all flying focal spot configurations was found to be 17.4 ± 1.0 s for a 512 row × 512 column × 32 slice volume. Reconstructions of the ACR phantom were found to meet all CT Accreditation Program criteria including CT number, CNR, and uniformity tests. Finally, reconstructed mass-attenuation coefficient values of water within the FORBILD thorax phantom agreed with original phantom values to within 0.0001 mm(2)/g (0.01%). FreeCT_wFBP is a fast, highly configurable reconstruction package for third-generation CT available under the GNU GPL. It shows good performance with both clinical and simulated data.

Synthesis, properties, and application in peptide chemistry of a magnetically separable and reusable biocatalyst

NASA Astrophysics Data System (ADS)

Liria, Cleber W.; Ungaro, Vitor A.; Fernandes, Raphaella M.; Costa, Natália J. S.; Marana, Sandro R.; Rossi, Liane M.; Machini, M. Teresa

2014-11-01

Enzyme-catalyzed chemical processes are selective, very productive, and generate little waste. Nevertheless, they may be optimized using enzymes bound to solid supports, which are particularly important for protease-mediated reactions since proteases undergo fast autolysis in solution. Magnetic nanoparticles are suitable supports for this purpose owing to their high specific surface area and to be easily separated from reaction media. Here we describe the immobilization of bovine α-chymotrypsin (αCT) on silica-coated superparamagnetic nanoparticles (Fe3O4@silica) and the characterization of the enzyme-nanoparticle hybrid (Fe3O4@silica-αCT) in terms of protein content, properties, recovery from reaction media, application, and reuse in enzyme-catalyzed peptide synthesis. The results revealed that (i) full acid hydrolysis of the immobilized protease followed by amino acid analysis of the hydrolyzate is a reliable method to determine immobilization yield; (ii) despite showing lower amidase activity and a lower K cat/ K m value for a specific substrate than free αCT, the immobilized enzyme is chemically and thermally more stable, magnetically recoverable from reaction media, and can be consecutively reused for ten cycles to catalyze the amide bond hydrolysis and ester hydrolysis of the protected dipeptide Z-Ala-Phe-OMe. Altogether, these properties indicate the potential of Fe3O4@silica-αCT to act as an efficient, suitably stable, and reusable catalyst in amino acid, peptide, and protein chemistry as well as in proteomic studies.

Muon-catalyzed D-T fusion at low temperature

NASA Astrophysics Data System (ADS)

Breunlich, W. H.; Cargnelli, M.; Kammel, P.; Marton, J.; Naegele, N.; Pawlek, P.; Scrinzi, A.; Werner, J.; Zmeskal, J.; Bistirlich, J.; Crowe, K. M.; Justice, M.; Kurck, J.; Petitjean, C.; Sherman, R. H.; Bossy, H.; Daniel, H.; Hartmann, F. J.; Neumann, W.; Schmidt, G.

1987-01-01

Muon-catalyzed deuterium-tritium fusion was investigated within a wide range of mixtures in liquid and gas (23-35 K) by detection of fusion neutrons. Our improved analysis includes hyperfine effects and allows a clear separation of intrinsic dt sticking ωs from kinetic effects. Strongly density-dependent cycle rates with values up to 1.45×108 s-1, yields of 113 fusions per muon, and ωs=(0.45+/-0.05)% are found. In comparison with previous experiments we confirm that ωs in liquid is lower than theoretically predicted, but do not find a strong dependence on either ct or density.

Physical analysis of breast cancer using dual-source computed tomography

NASA Astrophysics Data System (ADS)

Kim, H. J.; Lee, H. K.; Cho, J. H.

2014-12-01

This study was aimed to analyze various physical characteristics of breast cancer using dual-source computed tomography (CT). A phantom study and a clinical trial were performed in order and a 64-multidetector CT device was used for the examinations. In the phantom study, single-source (SS) CT was set up with a conventional scanning condition that is usually applied for breast CT examination and implementation was done at tube voltage of 120 kVp. Dual-source CT acquired images by irradiating X-ray sources with fast switching between two kilovoltage settings (80 and 140 kVp). After scanning, Hounsfield Unit (HU) values and radiation doses in a region of interest were measured and analyzed. In the clinical trial, the HU values were measured and analyzed after single-source computed tomography (SSCT) and dual-source CT in patients diagnosed with breast cancer. Also, the tumor size measured by dual-source CT was compared with the actual tumor size. The phantom study determined that the tumor region was especially measured by dual-source CT, while nylon fiber and specks region were especially measured by SSCT. The radiation dose was high with dual-source CT. The clinical trial showed a higher HU value of cancerous regions when scanned by dual-source CT compared with SSCT.

PET-PANC: multicentre prospective diagnostic accuracy and health economic analysis study of the impact of combined modality 18fluorine-2-fluoro-2-deoxy-d-glucose positron emission tomography with computed tomography scanning in the diagnosis and management of pancreatic cancer.

PubMed

Ghaneh, Paula; Hanson, Robert; Titman, Andrew; Lancaster, Gill; Plumpton, Catrin; Lloyd-Williams, Huw; Yeo, Seow Tien; Edwards, Rhiannon Tudor; Johnson, Colin; Abu Hilal, Mohammed; Higginson, Antony P; Armstrong, Tom; Smith, Andrew; Scarsbrook, Andrew; McKay, Colin; Carter, Ross; Sutcliffe, Robert P; Bramhall, Simon; Kocher, Hemant M; Cunningham, David; Pereira, Stephen P; Davidson, Brian; Chang, David; Khan, Saboor; Zealley, Ian; Sarker, Debashis; Al Sarireh, Bilal; Charnley, Richard; Lobo, Dileep; Nicolson, Marianne; Halloran, Christopher; Raraty, Michael; Sutton, Robert; Vinjamuri, Sobhan; Evans, Jonathan; Campbell, Fiona; Deeks, Jon; Sanghera, Bal; Wong, Wai-Lup; Neoptolemos, John P

2018-02-01

Pancreatic cancer diagnosis and staging can be difficult in 10-20% of patients. Positron emission tomography (PET)/computed tomography (CT) adds precise anatomical localisation to functional data. The use of PET/CT may add further value to the diagnosis and staging of pancreatic cancer. To determine the incremental diagnostic accuracy and impact of PET/CT in addition to standard diagnostic work-up in patients with suspected pancreatic cancer. A multicentre prospective diagnostic accuracy and clinical value study of PET/CT in suspected pancreatic malignancy. Patients with suspected pancreatic malignancy. All patients to undergo PET/CT following standard diagnostic work-up. The primary outcome was the incremental diagnostic value of PET/CT in addition to standard diagnostic work-up with multidetector computed tomography (MDCT). Secondary outcomes were (1) changes in patients' diagnosis, staging and management as a result of PET/CT; (2) changes in the costs and effectiveness of patient management as a result of PET/CT; (3) the incremental diagnostic value of PET/CT in chronic pancreatitis; (4) the identification of groups of patients who would benefit most from PET/CT; and (5) the incremental diagnostic value of PET/CT in other pancreatic tumours. Between 2011 and 2013, 589 patients with suspected pancreatic cancer underwent MDCT and PET/CT, with 550 patients having complete data and in-range PET/CT. Sensitivity and specificity for the diagnosis of pancreatic cancer were 88.5% and 70.6%, respectively, for MDCT and 92.7% and 75.8%, respectively, for PET/CT. The maximum standardised uptake value (SUV max. ) for a pancreatic cancer diagnosis was 7.5. PET/CT demonstrated a significant improvement in relative sensitivity ( p  = 0.01) and specificity ( p  = 0.023) compared with MDCT. Incremental likelihood ratios demonstrated that PET/CT significantly improved diagnostic accuracy in all scenarios ( p  < 0.0002). PET/CT correctly changed the staging of pancreatic cancer in 56 patients ( p  = 0.001). PET/CT influenced management in 250 (45%) patients. PET/CT stopped resection in 58 (20%) patients who were due to have surgery. The benefit of PET/CT was limited in patients with chronic pancreatitis or other pancreatic tumours. PET/CT was associated with a gain in quality-adjusted life-years of 0.0157 (95% confidence interval -0.0101 to 0.0430). In the base-case model PET/CT was seen to dominate MDCT alone and is thus highly likely to be cost-effective for the UK NHS. PET/CT was seen to be most cost-effective for the subgroup of patients with suspected pancreatic cancer who were thought to be resectable. PET/CT provided a significant incremental diagnostic benefit in the diagnosis of pancreatic cancer and significantly influenced the staging and management of patients. PET/CT had limited utility in chronic pancreatitis and other pancreatic tumours. PET/CT is likely to be cost-effective at current reimbursement rates for PET/CT to the UK NHS. This was not a randomised controlled trial and therefore we do not have any information from patients who would have undergone MDCT only for comparison. In addition, there were issues in estimating costs for PET/CT. Future work should evaluate the role of PET/CT in intraductal papillary mucinous neoplasm and prognosis and response to therapy in patients with pancreatic cancer. Current Controlled Trials ISRCTN73852054 and UKCRN 8166. The National Institute for Health Research Health Technology Assessment programme.

The Rate of Return to Schooling and the Business Cycle: Additional Estimates.

ERIC Educational Resources Information Center

Kniesner, Thomas J.; And Others

1980-01-01

Illustrates that the business cycle does indeed disturb relative Black/White rates of return to schooling. Blacks fare relatively poorly in times of high unemployment. Data tables and formulas are presented to support the argument. (CT)

Selection of Reference Genes for Quantitative Gene Expression in Porcine Mesenchymal Stem Cells Derived from Various Sources along with Differentiation into Multilineages

PubMed Central

Lee, Won-Jae; Jeon, Ryoung-Hoon; Jang, Si-Jung; Park, Ji-Sung; Lee, Seung-Chan; Baregundi Subbarao, Raghavendra; Lee, Sung-Lim; Park, Bong-Wook; King, William Allan; Rho, Gyu-Jin

2015-01-01

The identification of stable reference genes is a prerequisite for ensuring accurate validation of gene expression, yet too little is known about stable reference genes of porcine MSCs. The present study was, therefore, conducted to assess the stability of reference genes in porcine MSCs derived from bone marrow (BMSCs), adipose (AMSCs), and skin (SMSCs) with their in vitro differentiated cells into mesenchymal lineages such as adipocytes, osteocytes, and chondrocytes. Twelve commonly used reference genes were investigated for their threshold cycle (Ct) values by qRT-PCR. The Ct values of candidate reference genes were analyzed by geNorm software to clarify stable expression regardless of experimental conditions. Thus, Pearson's correlation was applied to determine correlation between the three most stable reference genes (NF3) and optimal number of reference genes (NFopt). In assessment of stability of reference gene across experimental conditions by geNorm analysis, undifferentiated MSCs and each differentiated status into mesenchymal lineages showed slightly different results but similar patterns about more or less stable rankings. Furthermore, Pearson's correlation revealed high correlation (r > 0.9) between NF3 and NFopt. Overall, the present study showed that HMBS, YWHAZ, SDHA, and TBP are suitable reference genes for qRT-PCR in porcine MSCs. PMID:25972899

Cutaneous lesions in pet rabbits following subcutaneous administration of a novel bivalent vaccine against myxomatosis and rabbit haemorrhagic disease.

PubMed

Selleri, Paolo; Di Girolamo, Nicola; Vögtlin, Andrea; Fileccia, Ivan; Hoop, Richard; Bongiovanni, Laura

2014-12-01

A novel bivalent vaccine to protect against myxomatosis and rabbit haemorrhagic disease is commercially available for pet rabbits. To describe the appearance of cutaneous lesions arising in pet rabbits positive for myxoma virus (MV) by RT-PCR evaluation shortly after vaccination. Four pet rabbits presenting with papular, crusting skin lesions ~10 days after vaccination. Histological evaluation of formalin-fixed skin biopsies obtained from lesional skin (case 1). Real-time polymerase chain reaction (RT-PCR) evaluation of paraffin-embedded tissue from skin biopsies (case 1) and crusts obtained from the lesion surface (cases 2-4) for myxoma virus are reported as cycle threshold (Ct ) values. Lesions affecting the ear pinna, dorsal aspect of the nose, vulva and/or conjunctiva are reported. Histopathological findings included severe ulcerative, necrotizing dermatitis and intralesional cytoplasmic inclusion bodies in myxoma cells. DNA was amplified from all the paraffin-embedded skin biopsies (Ct  = 34-35) and crusts (Ct  = 20-24). Although a wild virus challenge cannot be definitively excluded, veterinarians and pet-owners should be aware that cutaneous lesions have been observed after vaccination with this novel vaccine in low numbers of rabbits. © 2014 ESVD and ACVD.

Thoracic computed tomography is an effective screening modality in patients with penetrating injuries to the chest.

PubMed

Strumwasser, Aaron; Chong, Vincent; Chu, Eveline; Victorino, Gregory P

2016-09-01

The precise role of thoracic CT in penetrating chest trauma remains to be defined. We hypothesized that thoracic CT effectively screens hemodynamically normal patients with penetrating thoracic trauma to surgery vs. expectant management (NOM). A ten-year review of all penetrating torso cases was retrospectively analyzed from our urban University-based trauma center. We included hemodynamically normal patients (systolic blood pressure ≥90) with penetrating chest injuries that underwent screening thoracic CT. Hemodynamically unstable patients and diaphragmatic injuries were excluded. The sensitivity, specificity, positive predictive value and negative predictive value were calculated. A total of 212 patients (mean injury severity score=24, Abbreviated Injury Score for Chest=3.9) met inclusion criteria. Of these, 84.3% underwent NOM, 9.1% necessitated abdominal exploration, 6.6% underwent exploration for retained hemothorax/empyema, 6.6% underwent immediate thoracic exploration for significant injuries on chest CT, and 1.0% underwent delayed thoracic exploration for missed injuries. Thoracic CT had a sensitivity of 82%, specificity of 99%, positive predictive value of 90%, a negative predictive value of 99%, and an accuracy of 99% in predicting surgery vs. NOM. Thoracic CT has a negative predictive value of 99% in triaging hemodynamically normal patients with penetrating chest trauma. Screening thoracic CT successfully excludes surgery in patients with non-significant radiologic findings. Copyright © 2016. Published by Elsevier Ltd.

[Preoperative CT Scan in middle ear cholesteatoma].

PubMed

Sethom, Anissa; Akkari, Khemaies; Dridi, Inès; Tmimi, S; Mardassi, Ali; Benzarti, Sonia; Miled, Imed; Chebbi, Mohamed Kamel

2011-03-01

To compare preoperative CT scan finding and per-operative lesions in patients operated for middle ear cholesteatoma, A retrospective study including 60 patients with cholesteatoma otitis diagnosed and treated within a period of 5 years, from 2001 to 2005, at ENT department of Military Hospital of Tunis. All patients had computed tomography of the middle and inner ear. High resolution CT scan imaging was performed using millimetric incidences (3 to 5 millimetres). All patients had surgical removal of their cholesteatoma using down wall technic. We evaluated sensitivity, specificity and predictive value of CT-scan comparing otitic damages and CT finding, in order to examine the real contribution of computed tomography in cholesteatoma otitis. CT scan analysis of middle ear bone structures shows satisfaction (with 83% of sensibility). The rate of sensibility decrease (63%) for the tympanic raff. Predictive value of CT scan for the diagnosis of cholesteatoma was low. However, we have noticed an excellent sensibility in the analysis of ossicular damages (90%). Comparative frontal incidence seems to be less sensible for the detection of facial nerve lesions (42%). But when evident on CT scan findings, lesions of facial nerve were usually observed preoperatively (spécificity 78%). Predictive value of computed tomography for the diagnosis of perilymphatic fistulae (FL) was low. In fact, CT scan imaging have showed FL only for four patients among eight. Best results can be obtained if using inframillimetric incidences with performed high resolution computed tomography. Preoperative computed tomography is necessary for the diagnosis and the evaluation of chronic middle ear cholesteatoma in order to show extending lesion and to detect complications. This CT analysis and surgical correlation have showed that sensibility, specificity and predictive value of CT-scan depend on the anatomic structure implicated in cholesteatoma damages.

Validation of Marek's disease diagnosis and monitoring of Marek's disease vaccines from samples collected in FTA cards.

PubMed

Cortes, Aneg L; Montiel, Enrique R; Gimeno, Isabel M

2009-12-01

The use of Flinders Technology Associates (FTA) filter cards to quantify Marek's disease virus (MDV) DNA for the diagnosis of Marek's disease (MD) and to monitor MD vaccines was evaluated. Samples of blood (43), solid tumors (14), and feather pulp (FP; 36) collected fresh and in FTA cards were analyzed. MDV DNA load was quantified by real-time PCR. Threshold cycle (Ct) ratios were calculated for each sample by dividing the Ct value of the internal control gene (glyceraldehyde-3-phosphate dehydrogenase) by the Ct value of the MDV gene. Statistically significant correlation (P < 0.05) within Ct ratios was detected between samples collected fresh and in FTA cards by using Pearson's correlation test. Load of serotype 1 MDV DNA was quantified in 24 FP, 14 solid tumor, and 43 blood samples. There was a statistically significant correlation between FP (r = 0.95), solid tumor (r = 0.94), and blood (r = 0.9) samples collected fresh and in FTA cards. Load of serotype 2 MDV DNA was quantified in 17 FP samples, and the correlation between samples collected fresh and in FTA cards was also statistically significant (Pearson's coefficient, r = 0.96); load of serotype 3 MDV DNA was quantified in 36 FP samples, and correlation between samples taken fresh and in FTA cards was also statistically significant (r = 0.84). MDV DNA samples extracted 3 days (t0) and 8 months after collection (t1) were used to evaluate the stability of MDV DNA in archived samples collected in FTA cards. A statistically significant correlation was found for serotype 1 (r = 0.96), serotype 2 (r = 1), and serotype 3 (r = 0.9). The results show that FTA cards are an excellent media to collect, transport, and archive samples for MD diagnosis and to monitor MD vaccines. In addition, FTA cards are widely available, inexpensive, and adequate for the shipment of samples nationally and internationally.

Impact of radiotherapy and chemotherapy on biomarkers of oxidative DNA damage in lung cancer patients.

PubMed

Crohns, Marika; Saarelainen, Seppo; Erhola, Marina; Alho, Hannu; Kellokumpu-Lehtinen, Pirkko

2009-07-01

To assess oxidative damage to DNA during lung cancer (LC) treatments. Urinary levels of 8-oxoguanine (8-oxoGua) and levels of 8-oxo-2'-deoxyguanosine (8-oxodG) from urine and whole blood were determined in 36 non-cancer controls and 65 LC patients before any treatments. Samples were also obtained of LC patients during and after radiotherapy (RT, n=33) and chemotherapy (CT, n=16). Stage IV LC patients had higher urinary 8-oxoGua and 8-oxodG levels than patients with stage I-III disease (p=0.044 and p=0.034, respectively). Urinary 8-oxodG levels increased during the first week of RT (p<0.001). Nuclear 8-oxodG increased during RT and 3 months after start of RT. Nuclear 8-oxodG levels also rose between the first two CT cycles (p=0.043), and urinary 8-oxodG levels during the sixth CT cycle (p=0.009). Urinary DNA damage biomarker levels may be associated with LC stage. Both RT and CT increase the parameters of DNA oxidation.

TH-C-BRD-06: A Novel MRI Based CT Artifact Correction Method for Improving Proton Range Calculation in the Presence of Severe CT Artifacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, P; Schreibmann, E; Fox, T

2014-06-15

Purpose: Severe CT artifacts can impair our ability to accurately calculate proton range thereby resulting in a clinically unacceptable treatment plan. In this work, we investigated a novel CT artifact correction method based on a coregistered MRI and investigated its ability to estimate CT HU and proton range in the presence of severe CT artifacts. Methods: The proposed method corrects corrupted CT data using a coregistered MRI to guide the mapping of CT values from a nearby artifact-free region. First patient MRI and CT images were registered using 3D deformable image registration software based on B-spline and mutual information. Themore » CT slice with severe artifacts was selected as well as a nearby slice free of artifacts (e.g. 1cm away from the artifact). The two sets of paired MRI and CT images at different slice locations were further registered by applying 2D deformable image registration. Based on the artifact free paired MRI and CT images, a comprehensive geospatial analysis was performed to predict the correct CT HU of the CT image with severe artifact. For a proof of concept, a known artifact was introduced that changed the ground truth CT HU value up to 30% and up to 5cm error in proton range. The ability of the proposed method to recover the ground truth was quantified using a selected head and neck case. Results: A significant improvement in image quality was observed visually. Our proof of concept study showed that 90% of area that had 30% errors in CT HU was corrected to 3% of its ground truth value. Furthermore, the maximum proton range error up to 5cm was reduced to 4mm error. Conclusion: MRI based CT artifact correction method can improve CT image quality and proton range calculation for patients with severe CT artifacts.« less

High dose microCT does not contribute towards improved microPET/CT image quantitative accuracy and can limit longitudinal scanning of small animals

NASA Astrophysics Data System (ADS)

McDougald, Wendy A.; Collins, Richard; Green, Mark; Tavares, Adriana A. S.

2017-10-01

Obtaining accurate quantitative measurements in preclinical Positron Emission Tomography/Computed Tomography (PET/CT) imaging is of paramount importance in biomedical research and helps supporting efficient translation of preclinical results to the clinic. The purpose of this study was two-fold: (1) to investigate the effects of different CT acquisition protocols on PET/CT image quality and data quantification; and (2) to evaluate the absorbed dose associated with varying CT parameters. Methods: An air/water quality control CT phantom, tissue equivalent material phantom, an in-house 3D printed phantom and an image quality PET/CT phantom were imaged using a Mediso nanoPET/CT scanner. Collected data was analyzed using PMOD software, VivoQuant software and National Electric Manufactures Association (NEMA) software implemented by Mediso. Measured Hounsfield Unit (HU) in collected CT images were compared to the known HU values and image noise was quantified. PET recovery coefficients (RC), uniformity and quantitative bias were also measured. Results: Only less than 2% and 1% of CT acquisition protocols yielded water HU values < -80 and air HU values < -840, respectively. Four out of eleven CT protocols resulted in more than 100 mGy absorbed dose. Different CT protocols did not impact PET uniformity and RC, and resulted in <4% overall bias relative to expected radioactive concentration. Conclusion: Preclinical CT protocols with increased exposure times can result in high absorbed doses to the small animals. These should be avoided, as they do not contributed towards improved microPET/CT image quantitative accuracy and could limit longitudinal scanning of small animals.

Reconstruction of a time-averaged midposition CT scan for radiotherapy planning of lung cancer patients using deformable registration.

PubMed

Wolthaus, J W H; Sonke, J J; van Herk, M; Damen, E M F

2008-09-01

lower lobe lung tumors move with amplitudes of up to 2 cm due to respiration. To reduce respiration imaging artifacts in planning CT scans, 4D imaging techniques are used. Currently, we use a single (midventilation) frame of the 4D data set for clinical delineation of structures and radiotherapy planning. A single frame, however, often contains artifacts due to breathing irregularities, and is noisier than a conventional CT scan since the exposure per frame is lower. Moreover, the tumor may be displaced from the mean tumor position due to hysteresis. The aim of this work is to develop a framework for the acquisition of a good quality scan representing all scanned anatomy in the mean position by averaging transformed (deformed) CT frames, i.e., canceling out motion. A nonrigid registration method is necessary since motion varies over the lung. 4D and inspiration breath-hold (BH) CT scans were acquired for 13 patients. An iterative multiscale motion estimation technique was applied to the 4D CT scan, similar to optical flow but using image phase (gray-value transitions from bright to dark and vice versa) instead. From the (4D) deformation vector field (DVF) derived, the local mean position in the respiratory cycle was computed and the 4D DVF was modified to deform all structures of the original 4D CT scan to this mean position. A 3D midposition (MidP) CT scan was then obtained by (arithmetic or median) averaging of the deformed 4D CT scan. Image registration accuracy, tumor shape deviation with respect to the BH CT scan, and noise were determined to evaluate the image fidelity of the MidP CT scan and the performance of the technique. Accuracy of the used deformable image registration method was comparable to established automated locally rigid registration and to manual landmark registration (average difference to both methods < 0.5 mm for all directions) for the tumor region. From visual assessment, the registration was good for the clearly visible features (e.g., tumor and diaphragm). The shape of the tumor, with respect to that of the BH CT scan, was better represented by the MidP reconstructions than any of the 4D CT frames (including MidV; reduction of "shape differences" was 66%). The MidP scans contained about one-third the noise of individual 4D CT scan frames. We implemented an accurate method to estimate the motion of structures in a 4D CT scan. Subsequently, a novel method to create a midposition CT scan (time-weighted average of the anatomy) for treatment planning with reduced noise and artifacts was introduced. Tumor shape and position in the MidP CT scan represents that of the BH CT scan better than MidV CT scan and, therefore, was found to be appropriate for treatment planning.

Age- and gender-specific estimates of cumulative CT dose over 5 years using real radiation dose tracking data in children.

PubMed

Lee, Eunsol; Goo, Hyun Woo; Lee, Jae-Yeong

2015-08-01

It is necessary to develop a mechanism to estimate and analyze cumulative radiation risks from multiple CT exams in various clinical scenarios in children. To identify major contributors to high cumulative CT dose estimates using actual dose-length product values collected for 5 years in children. Between August 2006 and July 2011 we reviewed 26,937 CT exams in 13,803 children. Among them, we included 931 children (median age 3.5 years, age range 0 days-15 years; M:F = 533:398) who had 5,339 CT exams. Each child underwent at least three CT scans and had accessible radiation dose reports. Dose-length product values were automatically extracted from DICOM files and we used recently updated conversion factors for age, gender, anatomical region and tube voltage to estimate CT radiation dose. We tracked the calculated CT dose estimates to obtain a 5-year cumulative value for each child. The study population was divided into three groups according to the cumulative CT dose estimates: high, ≥30 mSv; moderate, 10-30 mSv; and low, <10 mSv. We reviewed clinical data and CT protocols to identify major contributors to high and moderate cumulative CT dose estimates. Median cumulative CT dose estimate was 5.4 mSv (range 0.5-71.1 mSv), and median number of CT scans was 4 (range 3-36). High cumulative CT dose estimates were most common in children with malignant tumors (57.9%, 11/19). High frequency of CT scans was attributed to high cumulative CT dose estimates in children with ventriculoperitoneal shunt (35 in 1 child) and malignant tumors (range 18-49). Moreover, high-dose CT protocols, such as multiphase abdomen CT (median 4.7 mSv) contributed to high cumulative CT dose estimates even in children with a low number of CT scans. Disease group, number of CT scans, and high-dose CT protocols are major contributors to higher cumulative CT dose estimates in children.

Role of multidetector computed tomography in evaluating incidentally detected breast lesions.

PubMed

Moschetta, Marco; Scardapane, Arnaldo; Lorusso, Valentina; Rella, Leonarda; Telegrafo, Michele; Serio, Gabriella; Angelelli, Giuseppe; Ianora, Amato Antonio Stabile

2015-01-01

Computed tomography (CT) does not represent the primary method for the evaluation of breast lesions; however, it can detect breast abnormalities, even when performed for other reasons related to thoracic structures. The aim of this study is to evaluate the potential benefits of 320-row multidetector CT (MDCT) in evaluating and differentiating incidentally detected breast lesions by using vessel probe and 3D analysis software with net enhancement value. Sixty-two breast lesions in 46 patients who underwent 320-row chest CT examination were retrospectively evaluated. CT scans were assessed searching for the presence, location, number, morphological features, and density of breast nodules. Net enhancement was calculated by subtracting precontrast density from the density obtained by postcontrast values. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of CT were calculated for morphological features and net enhancement. Thirty of 62 lesions were found to be malignant at histological examination and 32 were found to be benign. When morphological features were considered, the sensitivity, specificity, accuracy, PPV, and NPV of CT were 87%, 100%, 88%, 100%, and 50%, respectively. Based on net enhancement, CT reached a sensitivity, specificity, accuracy, PPV, and NPV of 100%, 94%, 97%, 94%, and 100%, respectively. MDCT allows to recognize and characterize breast lesions based on morphological features. Net enhancement can be proposed as an additional accurate feature of CT.

A single institution study of radiation dose received from CT imaging: A comparison to Malaysian NDRL

NASA Astrophysics Data System (ADS)

Osman, N. D.; Shamsuri, S. B. M.; Tan, Y. W.; Razali, M. A. S. M.; Isa, S. M.

2017-05-01

Advancement of CT technology has led to an increase in CT scanning as it improves the diagnosis. However, it is important to assess health risk of patients associated with ionising radiation received from CT. This study evaluated current dose distributions at Advanced Medical and Dental Institute (AMDI), Malaysia and was used to establish Local Diagnostic Reference Level (LDRL). Dose indicators such as CT Dose Index (CTDIvol and CTDIw) and Dose-Length Product (DLP) were gathered for all routine CT examinations performed at the Imaging Unit, AMDI from January 2015 to June 2016. The first and third quartile values for each dose indicator were determined. A total of 364 CT studies were performed during that period with the highest number of cases being Thorax-Abdomen-Pelvis (TAP) study (57% of total study). The CTDIw ranged between 2.0 mGy to 23.4 mGy per procedure. DLP values were ranged between 94 mGy.cm to 1687 mGy.cm. The local dose data was compared with the national DRL to monitor the current CT practice at AMDI and LDRL will be established from the calculated third quartile values of dose distribution. From the results, some of the local dose values exceeded the Malaysian and further evaluation is important to ensure the dose optimisation for patients.

[Diagnostic value of ¹⁸F-fluorodexyglucose positron emission tomography combined with contrast enhanced computed tomography in colorectal cancer liver metastasis].

PubMed

Zhang, Zhanwen; Lyu, Qinghu; Chen, Feini; Liao, Siqin; Zhang, Jie; Hu, Rui; Hu, Ping

2015-03-01

To explore the preoperative diagnostic value of ¹⁸F-fluorodexyglucose positron emission tomography combined with contrast enhanced computed tomography (¹⁸F-FDG PET-ceCT) in patients with colorectal cancer liver metastasis. Clinical and imaging data of 58 patients with suspicious colorectal cancer liver metastasis between April 2010 and March 2013 were retrospectively evaluated. All the patients underwent ¹⁸F-FDG PET-ceCT. On the basis of definitive diagnosis, the sensitivity, specificity, accuracy and consistency of routine PET-CT, ceCT and ¹⁸F-FDG PET-ceCT were calculated. A total of 147 suspicious lesions of colorectal cancer liver metastasis were found in 58 patients. Finally, 125 lesions were confinmed as malignant, of which 58 (46.4%) lesions were less than 1.0 cm. The other 22 lesions were confinmed as benign, of which 17 (77.3%) lesions were less than 1.0 cm. The diagnostic accuracy of routine PET-CT, ceCT and ¹⁸F-FDG PET-ceCT in colorectal cancer liver metastasis for the lesions more than 1.0 cm was 100%, 93.1%, 100% respectively, and the consistency with final diagnosis was perfect, moderate, and perfect respectively (Kappa value 01.00, 0.408, 1.00). For the lesions less than 1.0 cm, the accuracy was 42.7%, 78.7%, 94.7% respectively, and the consistency with definitive diagnosis was insignificance, fair, and almost perfect respectively (Kappa value -0.005, 0.305, 0.848). The area under curve(AUC) was 0.525 (95% CI: 0.407-0.462) for routine PET-CT, 0.651(95% CI:0.532-0.757) for ceCT, and 0.924 (95% CI:0.839-0.972) for ¹⁸F-FDG PET-ceCT respectively. The AUC of ¹⁸F-FDG PET-ceCT was significantly larger than that of routine PET-CT (Z=5.559, P<0.05) or ceCT (Z=4.183, P<0.05). (18)F-FDG PET-ceCT can improve the diagnostic accuracy for smaller lesions of colorectal cancer liver metastasis.

SU-F-J-224: Impact of 4D PET/CT On PERCIST Classification of Lung and Liver Metastases in NSLC and Colorectal Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meier, J; Lopez, B; Mawlawi, O

2016-06-15

Purpose: To quantify the impact of 4D PET/CT on PERCIST metrics in lung and liver tumors in NSCLC and colorectal cancer patients. Methods: 32 patients presenting lung or liver tumors of 1–3 cm size affected by respiratory motion were scanned on a GE Discovery 690 PET/CT. The bed position with lesion(s) affected by motion was acquired in a 12 minute PET LIST mode and unlisted into 8 bins with respiratory gating. Three different CT maps were used for attenuation correction: a clinical helical CT (CT-clin), an average CT (CT-ave), and an 8-phase 4D CINE CT (CT-cine). All reconstructions were 3Dmore » OSEM, 2 iterations, 24 subsets, 6.4 Gaussian filtration, 192×192 matrix, non-TOF, and non-PSF. Reconstructions using CT-clin and CT-ave used only 3 out of the 12 minutes of the data (clinical protocol); all 12 minutes were used for the CT-cine reconstruction. The percent change of SUVbw-peak and SUVbw-max was calculated between PET-CTclin and PET-CTave. The same percent change was also calculated between PET-CTclin and PET-CTcine in each of the 8 bins and in the average of all bins. A 30% difference from PET-CTclin classified lesions as progressive metabolic disease (PMD) using maximum bin value and the average of eight bin values. Results: 30 lesions in 25 patients were evaluated. Using the bin with maximum SUVbw-peak and SUVbw-max difference, 4 and 13 lesions were classified as PMD, respectively. Using the average bin values for SUVbw-peak and SUVbw-max, 3 and 6 lesions were classified as PMD, respectively. Using PET-CTave values for SUVbw-peak and SUVbw-max, 4 and 3 lesions were classified as PMD, respectively. Conclusion: These results suggest that response evaluation in 4D PET/CT is dependent on SUV measurement (SUVpeak vs. SUVmax), number of bins (single or average), and the CT map used for attenuation correction.« less

[Quantitative Evaluation of Metal Artifacts on CT Images on the Basis of Statistics of Extremes].

PubMed

Kitaguchi, Shigetoshi; Imai, Kuniharu; Ueda, Suguru; Hashimoto, Naomi; Hattori, Shouta; Saika, Takahiro; Ono, Yoshifumi

2016-05-01

It is well-known that metal artifacts have a harmful effect on the image quality of computed tomography (CT) images. However, the physical property remains still unknown. In this study, we investigated the relationship between metal artifacts and tube currents using statistics of extremes. A commercially available phantom for measuring CT dose index 160 mm in diameter was prepared and a brass rod 13 mm in diameter was placed at the centerline of the phantom. This phantom was used as a target object to evaluate metal artifacts and was scanned using an area detector CT scanner with various tube currents under a constant tube voltage of 120 kV. Sixty parallel line segments with a length of 100 pixels were placed to cross metal artifacts on CT images and the largest difference between two adjacent CT values in each of 60 CT value profiles of these line segments was employed as a feature variable for measuring metal artifacts; these feature variables were analyzed on the basis of extreme value theory. The CT value variation induced by metal artifacts was statistically characterized by Gumbel distribution, which was one of the extreme value distributions; namely, metal artifacts have the same statistical characteristic as streak artifacts. Therefore, Gumbel evaluation method makes it possible to analyze not only streak artifacts but also metal artifacts. Furthermore, the location parameter in Gumbel distribution was shown to be in inverse proportion to the square root of a tube current. This result suggested that metal artifacts have the same dose dependence as image noises.

Fusion positron emission/computed tomography underestimates the presence of hilar nodal metastases in patients with resected non-small cell lung cancer.

PubMed

Carrillo, Sergio A; Daniel, Vincent C; Hall, Nathan; Hitchcock, Charles L; Ross, Patrick; Kassis, Edmund S

2012-05-01

The 5-year survival for patients with resected stage II (N1) non-small cell lung cancer ranges from 40% to 55%. No data exist addressing the benefit of neoadjuvant therapy for patients with stage II disease. This is largely in part due to the lack of a reliable, minimally invasive method to assess hilar nodes. This study is aimed at determining the ability of fusion positron emission/computed tomography (PET/CT) to identify hilar metastases in patients with resected non-small cell lung cancer. A retrospective review of surgically resected patients with fusion PET/CT within 30 days of resection was performed. The sensitivity, specificity, positive predictive value, and negative predictive value for PET/CT in detecting hilar nodal metastases was calculated for a range of maximum standardized uptake values (SUVmax). Hilar nodes from patients with falsely positive PET/CT scans were analyzed for the presence of histoplasmosis. Additionally, the impact of hilar node size greater than 1 centimeter on the calculated values was assessed. There were 119 patients evaluated. The number of lymph nodes resected ranged from 1 to 12 (X=2.98). There was decreased sensitivity and increased specificity with higher SUVmax cutoff values. At the standard SUVmax value of 2.5, the sensitivity and specificity were only 48.5% and 80.2%. The addition of size of hilar node by CT led to a modest improvement in sensitivity at all SUVmax cutoff values. Fusion PET/CT lacks sensitivity and specificity in identifying hilar nodal metastasis in patients with resected non-small cell lung cancer. Further prospective studies assessing the utility of PET/CT versus alternative sampling techniques are warranted. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Comparison Between 64Cu-PSMA-617 PET/CT and 18F-Choline PET/CT Imaging in Early Diagnosis of Prostate Cancer Biochemical Recurrence.

PubMed

Cantiello, Francesco; Crocerossa, Fabio; Russo, Giorgio Ivan; Gangemi, Vincenzo; Ferro, Matteo; Vartolomei, Mihai Dorin; Lucarelli, Giuseppe; Mirabelli, Maria; Scafuro, Chiara; Ucciero, Giuseppe; De Cobelli, Ottavio; Morgia, Giuseppe; Damiano, Rocco; Cascini, Giuseppe Lucio

2018-06-04

To evaluate the diagnostic performance of 64 Cu-PSMA-617 positron emission tomography (PET) with computed tomography (CT) for restaging prostate cancer after biochemical recurrence (BCR) and to compare it with 18 F-choline PET/CT in a per-patient analysis. An observational study was performed of 43 patients with BCR after laparoscopic radical prostatectomy who underwent 64 Cu-PSMA-617 PET/CT and subsequently 18 F-choline PET/CT for restaging. The detection rates (DR) of 64 Cu-PSMA-617 PET/CT and of 18 F-choline PET/CT were calculated by standardized maximum uptake value (SUV max ) at 4 hours and SUV max at 1 hour as reference, respectively. Furthermore, univariate logistic regression analysis was carried out to identify independent predictive factors of positivity with 64 Cu-PSMA-617 PET/CT. An overall positivity with 64 Cu-PSMA-617 PET/CT was found in 32 patients (74.4%) versus 19 (44.2%) with 18 F-choline PET/CT. Specifically, after stratifying for prostate-specific antigen (PSA) values, we found a good performance of 64 Cu-PSMA-617 PET/CT at low PSA levels compared to 18 F-choline PET/CT, with a DR of 57.1% versus 14.3% for PSA 0.2-0.5 ng/mL (P = .031), and of 60% versus 30% with PSA 0.5-1 ng/mL. At univariate binary logistic regression analysis, PSA level was the only independent predictor of 64 Cu-PSMA-617 PET/CT positivity. No significant difference in terms of DR for both 64 Cu-PSMA-617 PET/CT and 18 F-choline PET/CT was found according to different Gleason score subgroups. In our study cohort, a better performance was observed for 64 Cu-PSMA-617 PET/CT compared to 18 F-choline PET/CT in restaging after BCR, especially in patients with low PSA values. Copyright © 2018 Elsevier Inc. All rights reserved.

Variability of dental cone beam CT grey values for density estimations

PubMed Central

Pauwels, R; Nackaerts, O; Bellaiche, N; Stamatakis, H; Tsiklakis, K; Walker, A; Bosmans, H; Bogaerts, R; Jacobs, R; Horner, K

2013-01-01

Objective The aim of this study was to investigate the use of dental cone beam CT (CBCT) grey values for density estimations by calculating the correlation with multislice CT (MSCT) values and the grey value error after recalibration. Methods A polymethyl methacrylate (PMMA) phantom was developed containing inserts of different density: air, PMMA, hydroxyapatite (HA) 50 mg cm−3, HA 100, HA 200 and aluminium. The phantom was scanned on 13 CBCT devices and 1 MSCT device. Correlation between CBCT grey values and CT numbers was calculated, and the average error of the CBCT values was estimated in the medium-density range after recalibration. Results Pearson correlation coefficients ranged between 0.7014 and 0.9996 in the full-density range and between 0.5620 and 0.9991 in the medium-density range. The average error of CBCT voxel values in the medium-density range was between 35 and 1562. Conclusion Even though most CBCT devices showed a good overall correlation with CT numbers, large errors can be seen when using the grey values in a quantitative way. Although it could be possible to obtain pseudo-Hounsfield units from certain CBCTs, alternative methods of assessing bone tissue should be further investigated. Advances in knowledge The suitability of dental CBCT for density estimations was assessed, involving a large number of devices and protocols. The possibility for grey value calibration was thoroughly investigated. PMID:23255537

Comparison of SUL values in oncological 18F-FDG PET/CT; The effect of new LBM formulas.

PubMed

Halsne, Trygve; Müller, Ebba Glørsen; Spiten, Ann-Eli; Sherwani, Alexander Gul; Mikalsen, Lars Tore Gyland; Rootwelt-Revheim, Mona-Elisabeth; Stokke, Caroline

2018-03-29

Due to better precision and intercompatibility, the use of lean body mass (LBM) as mass estimate in the calculation of standardized uptake values (SUV) has become more common in research and clinical studies today. Thus, the equations deciding this quantity have to be verified in order to choose the ones that best represents the actual body composition. Methods: LBM was calculated for 44 patients examined with 18 F-FDG PET/CT scans by means of James' and Janmahasatians' sex specific predictive equations and the results validated using a CT based methods. The latter method makes use of the eyes-to-thighs CT from the PET/CT acquisition protocol and segments the voxels according to Hounsfield Units. Intraclass correlation coefficients (ICC) and Bland-Altman plots have been used to assess agreement between the various methods. Results: A mean difference of 6.3kg (-15.1 kg to 2.5 kg LOA) between LBM james and LBM CT1 was found. This is higher than the observed mean difference of 3.8kg (-12.5 kg to 4.9 kg LOA) between LBM jan and LBM CT1 In addition, LBM jan had higher ICC with LBM CT1 of r I = 0.87 ( r L = 0.60, r U = 0.94) than LBM james with r I = 0.77 ( r L = 0.11, r U = 0.91). Thus, we obtained better agreement between and LBM jan and LBM CT1 Although there were exceptions, the overall effect on SUL values was that SULjames values were greater than SULjan values. Conclusion: From our results, we have verified the reliability of the LBM jan suggested formulas with a CT derived reference standard. Compared with the more traditional and available set of equations LBM james the LBM jan formulas tend to yield better agreement. Copyright © 2018 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

CBF measured by Xe-CT: Approach to analysis and normal values

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yonas, H.; Darby, J.M.; Marks, E.C.

1991-09-01

Normal reference values and a practical approach to CBF analysis are needed for routine clinical analysis and interpretation of xenon-enhanced computed tomography (CT) CBF studies. The authors measured CBF in 67 normal individuals with the GE 9800 CT scanner adapted for CBF imaging with stable Xe. CBF values for vascular territories were systematically analyzed using the clustering of contiguous 2-cm circular regions of interest (ROIs) placed within the cortical mantle and basal ganglia. Mixed cortical flows averaged 51 {plus minus} 10ml.100g-1.min-1. High and low flow compartments, sampled by placing 5-mm circular ROIs in regions containing the highest and lowest flowmore » values in each hemisphere, averaged 84 {plus minus} 14 and 20 {plus minus} 5 ml.100 g-1.min-1, respectively. Mixed cortical flow values as well as values within the high flow compartment demonstrated significant decline with age; however, there were no significant age-related changes in the low flow compartment. The clustering of systematically placed cortical and subcortical ROIs has provided a normative data base for Xe-CT CBF and a flexible and uncomplicated method for the analysis of CBF maps generated by Xe-enhanced CT.« less

CT-P6 compared with reference trastuzumab for HER2-positive breast cancer: a randomised, double-blind, active-controlled, phase 3 equivalence trial.

PubMed

Stebbing, Justin; Baranau, Yauheni; Baryash, Valeriy; Manikhas, Alexey; Moiseyenko, Vladimir; Dzagnidze, Giorgi; Zhavrid, Edvard; Boliukh, Dmytro; Stroyakovskii, Daniil; Pikiel, Joanna; Eniu, Alexandru; Komov, Dmitry; Morar-Bolba, Gabriela; Li, Rubi K; Rusyn, Andriy; Lee, Sang Joon; Lee, Sung Young; Esteva, Francisco J

2017-07-01

CT-P6 is a proposed biosimilar to reference trastuzumab. In this study, we aimed to establish equivalence of CT-P6 to reference trastuzumab in neoadjuvant treatment of HER2-positive early-stage breast cancer. In this randomised, double-blind, active-controlled, phase 3 equivalence trial, we recruited women aged 18 years or older with stage I-IIIa operable HER2-positive breast cancer from 112 centres in 23 countries. Inclusion criteria were an Eastern Cooperative Oncology Group performance status score of 0 or 1; a normal left ventricular ejection fraction of at least 55%; adequate bone marrow, hepatic, and renal function; at least one measureable lesion; and known oestrogen and progesterone receptor status. Exclusion criteria included bilateral breast cancer, previous breast cancer treatment, previous anthracycline treatment, and pregnancy or lactation. We randomly allocated patients 1:1 to receive neoadjuvant CT-P6 or reference trastuzumab intravenously (eight cycles, each lasting 3 weeks, for 24 weeks; 8 mg/kg on day 1 of cycle 1 and 6 mg/kg on day 1 of cycles 2-8) in conjunction with neoadjuvant docetaxel (75 mg/m 2 on day 1 of cycles 1-4) and FEC (fluorouracil [500 mg/m 2 ], epirubicin [75 mg/m 2 ], and cyclophosphamide [500 mg/m 2 ]; day 1 of cycles 5-8) therapy. We stratified randomisation by clinical stage, receptor status, and country and used permuted blocks. We did surgery within 3-6 weeks of the final neoadjuvant study drug dose, followed by an adjuvant treatment period of up to 1 year. We monitored long-term safety and efficacy for 3 years after the last patient was enrolled. Participants and investigators were masked to treatment until study completion. The primary efficacy endpoint, analysed in the per-protocol population, was pathological complete response, assessed via specimens obtained during surgery, analysed by masked central review of local histopathology reports. The equivalence margin was -0·15 to 0·15. This trial is registered with ClinicalTrials.gov, number NCT02162667, and is ongoing, but no longer recruiting. Between Aug 7, 2014, and May 6, 2016, we randomly allocated 549 patients (271 [49%] to CT-P6 vs 278 [51%] to reference trastuzumab). A similar proportion of patients achieved pathological complete response with CT-P6 (116 [46·8%; 95% CI 40·4-53·2] of 248 patients) and reference trastuzumab (129 [50·4%; 44·1-56·7] of 256 patients). The 95% CI of the estimated treatment outcome difference (-0·04% [95% CI -0·12 to 0·05]) was within the equivalence margin. 19 (7%) of 271 patients in the CT-P6 group reported serious treatment-emergent adverse events versus 22 (8%) of 278 in the reference trastuzumab group; frequent (occurring in more than one patient) serious adverse events were febrile neutropenia (four [1%] vs one [<1%]) and neutropenia (one [<1%] vs two [1%]). Grade 3 or worse treatment-related adverse events occurred in 17 (6%) of 271 patients in the CT-P6 group versus 23 (8%) of 278 in the reference trastuzumab group; the most frequently reported adverse event was neutropenia in ten (4%) versus 14 (5%). CT-P6 showed equivalent efficacy to reference trastuzumab and adverse events were similar. Availability of trastuzumab biosimilars could increase access to this targeted therapy for HER2-positive early-stage cancer. Celltrion Inc. Copyright © 2017 Elsevier Ltd. All rights reserved.

The application of "natural" growth rates of Heterostegina depressa to infer timing of reproduction events

NASA Astrophysics Data System (ADS)

Eder, Wolfgang; Julia, Woeger; Kinoshita, Shunichi; Hohenegger, Johann; Briguglio, Antonino

2017-04-01

To explore applicability of the natural laboratory approach (sensu Hohenegger) on population dynamic studies of recent larger benthic foraminifera, this relatively new experimental method has been applied on Heterostegina depressa populations from Sesoko Jima, NW Okinawa, Japan. It is used to gain an averaged chamber and diameter building rate, as well as the average longevity of H. depressa based on monthly samplings at fixed sampling stations. Samples were collected by SCUBA in 16 monthly intervals around 20 and 50 meters water depth, wherefrom live populations were dried and investigated by microCT. The specimens were measured regarding chamber number and maximum diameter. This biometric data has been tested for the presence of multiple generations of H. depressa megalospheres. In case of skewed or bimodal frequency distributions, they were decomposed into normally distributed components. Means and standard deviations of each component of every month were extracted and could be used to calculate the maximum values of chamber number and diameter for all sampling intervals. Based on these maximal values, the natural chamber/diameter growth rate was fitted by Michaelis-Menten functions. By inversion of this growth functions the birthdate of every specimen was calculated. Frequency diagrams of these dates reveal a continuous background reproduction throughout the year, yet show distinct reproduction peaks in late spring and late autumn. Further, sinusoidal regression analysis support these two main reproduction cycles, one short-term cycle 70 days and a one long-term cycles around 180 days. Surprisingly, similar cycles have been found in different studies on volumetric growth of larger benthic foraminifera.

Systematic review on the value of CT scanning in the diagnosis of anastomotic leakage after colorectal surgery.

PubMed

Kornmann, Verena N N; Treskes, Nikki; Hoonhout, Lilian H F; Bollen, Thomas L; van Ramshorst, Bert; Boerma, Djamila

2013-04-01

Timely diagnosis of anastomotic leakage after colorectal surgery and adequate treatment is important to reduce morbidity and mortality. Abdominal computed tomography (CT) scanning is the diagnostic tool of preference, but its value may be questionable in the early postoperative period. The accuracy of CT scanning for the detection of anastomotic leakage and its role in timing of intervention was evaluated. A systematic literature search was performed. Relevant publications were identified from four electronic databases between 1990 and 2011. Inclusion criteria were human studies, studies published in English or Dutch, colorectal surgery with primary anastomosis, and abdominal CT scan with reported outcome for the detection of anastomotic leakage. Exclusion criteria were cohort of fewer than five patients, other gastrointestinal surgery, no anastomosis, and radiological imaging other than CT. Eight studies, including 221 abdominal CT scans, fulfilled the inclusion criteria. Overall, the methodological quality of the studies was poor. The overall sensitivity of CT scanning to diagnose leakage was 0.68 (95 % confidence interval 0.59-0.75) for colonic resection. Data on the sequelae of false-negative CT scanning was not available. There is limited good-quality evidence to determine the value of CT scans in the detection of anastomotic leakage. To prevent delay in diagnosis and appropriate treatment of anastomotic leakage, the relatively low sensitivity of CT scanning must be taken into account.

Clinical values of (18) F-FDG PET/CT in oral cavity cancer with dental artifacts on CT or MRI.

PubMed

Hong, Hye Ran; Jin, Soyoung; Koo, Hyun Jung; Roh, Jong-Lyel; Kim, Jae Seung; Cho, Kyung-Ja; Choi, Seung-Ho; Nam, Soon Yuhl; Kim, Sang Yoon

2014-11-01

2a To investigate the role of (18) F-FDG PET/CT in tumor staging, extent, and volume measurements in oral cavity squamous cell carcinoma (OSCC) patients with/without dental artifacts on CT or MRI. This study was conducted in 63 consecutive patients with OSCC who received initial workups including (18) F-FDG PET/CT and MRI. The results of the imaging modalities were compared to those of pathology, using McNemar's test and the paired t-test. Thirty-seven patients (59%) had dental or metallic artifacts obscuring primary tumors. (18) F-FDG PET/CT scanning was superior to MRI in tumor staging (weighted κ = 0.870 vs. 0.518, P = 0.004) in patients with dental artifacts. In addition, (18) F-FDG PET/CT scans were more specific than MRI in detecting sublingual gland (P = 0.014) and mouth floor (P = 0.011) involvement. In patients with dental artifacts, there was a significant discrepancy between primary tumor volume (PTV) measured by pathology and MRI (P = 0.018), but not between PTV measured from pathology and (18) F-FDG PET/CT at SUV2.5 (P = 0.245), which showed the highest intraclass correlation coefficient value (0.860). (18) F-FDG PET/CT scans provide accurate tumor staging and volume measurements in OSCC patients with CR/MRI dental artifacts, leading to improved preoperative planning. 2b CONDENSED ABSTRACT This study evaluated the clinical value of (18) F-FDG PET/CT in 63 patients with oral cavity cancers. In 37 (59%) patients with dental artifacts on CT/MRI, (18) F-FDG PET/CT showed superior results compared to MRI in tumor staging and represented the highest intraclass correlation coefficient value to tumor volume determined by pathology. © 2014 Wiley Periodicals, Inc.

Optimization of SPECT-CT Hybrid Imaging Using Iterative Image Reconstruction for Low-Dose CT: A Phantom Study

PubMed Central

Grosser, Oliver S.; Kupitz, Dennis; Ruf, Juri; Czuczwara, Damian; Steffen, Ingo G.; Furth, Christian; Thormann, Markus; Loewenthal, David; Ricke, Jens; Amthauer, Holger

2015-01-01

Background Hybrid imaging combines nuclear medicine imaging such as single photon emission computed tomography (SPECT) or positron emission tomography (PET) with computed tomography (CT). Through this hybrid design, scanned patients accumulate radiation exposure from both applications. Imaging modalities have been the subject of long-term optimization efforts, focusing on diagnostic applications. It was the aim of this study to investigate the influence of an iterative CT image reconstruction algorithm (ASIR) on the image quality of the low-dose CT images. Methodology/Principal Findings Examinations were performed with a SPECT-CT scanner with standardized CT and SPECT-phantom geometries and CT protocols with systematically reduced X-ray tube currents. Analyses included image quality with respect to photon flux. Results were compared to the standard FBP reconstructed images. The general impact of the CT-based attenuation maps used during SPECT reconstruction was examined for two SPECT phantoms. Using ASIR for image reconstructions, image noise was reduced compared to FBP reconstructions for the same X-ray tube current. The Hounsfield unit (HU) values reconstructed by ASIR were correlated to the FBP HU values(R2 ≥ 0.88) and the contrast-to-noise ratio (CNR) was improved by ASIR. However, for a phantom with increased attenuation, the HU values shifted for low X-ray tube currents I ≤ 60 mA (p ≤ 0.04). In addition, the shift of the HU values was observed within the attenuation corrected SPECT images for very low X-ray tube currents (I ≤ 20 mA, p ≤ 0.001). Conclusion/Significance In general, the decrease in X-ray tube current up to 30 mA in combination with ASIR led to a reduction of CT-related radiation exposure without a significant decrease in image quality. PMID:26390216

Cat-Scratch Disease: A Pitfall for Lymphoma Evaluation by FDG-PET/CT.

PubMed

Dubreuil, Julien; Dony, Arthur; Salles, Gilles; Traverse-Glehen, Alexandra; Giammarile, Francesco; Skanjeti, Andrea

2017-02-01

FDG-PET/CT is a standard of care in staging and response assessment of Hodgkin lymphoma. Hence, it is important to recognize pitfalls owing to the potential therapeutic impact. We report a case of a 29-year-old woman affected by stage III bulky Hodgkin lymphoma. The interim FDG-PET/CT showed a complete metabolic response. After three new cycles of chemotherapy, the patient showed fever and lymphadenopathy at clinic examination, PET/CT revealed several FDG uptakes at lymph nodes in inguinal and iliac region. Pathologic analyses, after biopsy and serologic examinations, led to the diagnosis of cat-scratch disease.

Comparison of synchrotron radiation and conventional x-ray microcomputed tomography for assessing trabecular bone microarchitecture of human femoral heads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chappard, Christine; Basillais, Armelle; Benhamou, Laurent

Microcomputed tomography ({mu}CT) produces three-dimensional (3D) images of trabecular bone. We compared conventional {mu}CT (C{mu}CT) with a polychromatic x-ray cone beam to synchrotron radiation (SR) {mu}CT with a monochromatic parallel beam for assessing trabecular bone microarchitecture of 14 subchondral femoral head specimens from patients with osteoarthritis (n=10) or osteoporosis (n=4). SR{mu}CT images with a voxel size of 10.13 {mu}m were reconstructed from 900 2D radiographic projections (angular step, 0.2 deg. ). C{mu}CT images with a voxel size of 10.77 {mu}m were reconstructed from 205, 413, and 825 projections obtained using angular steps of 0.9 deg., 0.45 deg., and 0.23 deg.,more » respectively. A single threshold was used to binarize the images. We computed bone volume/tissue volume (BV/TV), bone surface/bone volume (BS/BV), trabecular number (Tb.N), trabecular thickness (Tb.Th and Tb.Th*), trabecular spacing (Tb.Sp), degree of anisotropy (DA), and Euler density. With the 0.9 deg. angular step, all C{mu}CT values were significantly different from SR{mu}CT values. With the 0.23 deg. and 0.45 deg. rotation steps, BV/TV, Tb.Th, and BS/BV by C{mu}CT differed significantly from the values by SR{mu}CT. The error due to slice matching (visual site matching {+-}10 slices) was within 1% for most parameters. Compared to SR{mu}CT, BV/TV, Tb.Sp, and Tb.Th by C{mu}CT were underestimated, whereas Tb.N and Tb.Th* were overestimated. A Bland and Altman plot showed no bias for Tb.N or DA. Bias was -0.8{+-}1.0%, +5.0{+-}1.1 {mu}m, -5.9{+-}6.3 {mu}m, and -5.7{+-}29.1 {mu}m for BV/TV, Tb.Th*, Tb.Th, and Tb.Sp, respectively, and the differences did not vary over the range of values. Although systematic differences were noted between SR{mu}CT and C{mu}CT values, correlations between the techniques were high and the differences would probably not change the discrimination between study groups. C{mu}CT provides a reliable 3D assessment of human defatted bone when working at the 0.23 deg. or 0.45 deg. rotation step; the 0.9 deg. rotation step may be insufficiently accurate for morphological bone analysis.« less

Prediction value of the Canadian CT head rule and the New Orleans criteria for positive head CT scan and acute neurosurgical procedures in minor head trauma: a multicenter external validation study.

PubMed

Bouida, Wahid; Marghli, Soudani; Souissi, Sami; Ksibi, Hichem; Methammem, Mehdi; Haguiga, Habib; Khedher, Sonia; Boubaker, Hamdi; Beltaief, Kaouthar; Grissa, Mohamed Habib; Trimech, Mohamed Naceur; Kerkeni, Wiem; Chebili, Nawfel; Halila, Imen; Rejeb, Imen; Boukef, Riadh; Rekik, Noureddine; Bouhaja, Bechir; Letaief, Mondher; Nouira, Semir

2013-05-01

The New Orleans Criteria and the Canadian CT Head Rule have been developed to decrease the number of normal computed tomography (CT) results in mild head injury. We compare the performance of both decision rules for identifying patients with intracranial traumatic lesions and those who require an urgent neurosurgical intervention after mild head injury. This was an observational cohort study performed between 2008 and 2011 on patients with mild head injury who were aged 10 years or older. We collected prospectively clinical head CT scan findings and outcome. Primary outcome was need for neurosurgical intervention, defined as either death or craniotomy, or the need of intubation within 15 days of the traumatic event. Secondary outcome was the presence of traumatic lesions on head CT scan. New Orleans Criteria and Canadian CT Head Rule decision rules were compared by using sensitivity specifications and positive and negative predictive value. We enrolled 1,582 patients. Neurosurgical intervention was performed in 34 patients (2.1%) and positive CT findings were demonstrated in 218 patients (13.8%). Sensitivity and specificity for need for neurosurgical intervention were 100% (95% confidence interval [CI] 90% to 100%) and 60% (95% CI 44% to 76%) for the Canadian CT Head Rule and 82% (95% CI 69% to 95%) and 26% (95% CI 24% to 28%) for the New Orleans Criteria. Negative predictive values for the above-mentioned clinical decision rules were 100% and 99% and positive values were 5% and 2%, respectively, for the Canadian CT Head Rule and New Orleans Criteria. Sensitivity and specificity for clinical significant head CT findings were 95% (95% CI 92% to 98%) and 65% (95% CI 62% to 68%) for the Canadian CT Head Rule and 86% (95% CI 81% to 91%) and 28% (95% CI 26% to 30%) for the New Orleans Criteria. A similar trend of results was found in the subgroup of patients with a Glasgow Coma Scale score of 15. For patients with mild head injury, the Canadian CT Head Rule had higher sensitivity than the New Orleans Criteria, with higher negative predictive value. The question of whether the use of the Canadian CT Head Rule would have a greater influence on head CT scan reduction requires confirmation in real clinical practice. Copyright © 2012 American College of Emergency Physicians. Published by Mosby, Inc. All rights reserved.

Study of Image Quality From CT Scanner Multi-Detector by using Americans College of Radiology (ACR) Phantom

NASA Astrophysics Data System (ADS)

Mulyadin; Dewang, Syamsir; Abdullah, Bualkar; Tahir, Dahlang

2018-03-01

In this study, the image quality of CT scan using phantom American College of Radiology (ACR) was determined. Scanning multidetector CT is used to know the image quality parameters by using a solid phantom containing four modules and primarily from materials that are equivalent to water. Each module is 4 cm in diameter and 20 cm in diameter. There is white alignment marks painted white to reflect the alignment laser and there are also “HEAD”, “FOOT”, and “TOP” marks on the phantom to help align. This test obtains CT images of each module according to the routine inspection protocol of the head. Acceptance of image quality obtained for determination: CT Number Accuracy (CTN), CT Number Uniformity and Noise, Linearity CT Number, Slice Technique, Low Contrast Resolution and High Contrast Resolution represent image quality parameters. In testing CT Number Accuracy (CTN), CT Uniform number and Noise are in the range of tolerable values allowed. In the test, Linearity CT Number obtained correlation value above 0.99 is the relationship between electron density and CT Number. In a low contrast resolution test, the smallest contrast groups are visible. In contrast, the high resolution is seen up to 7 lp/cm. The quality of GE CT Scan is very high, as all the image quality tests obtained are within the tolerance brackets of values permitted by the Nuclear Power Control Agency (BAPETEN). Image quality test is a way to get very important information about the accuracy of snoring result by using phantom ACR.

Algorithm of pulmonary emphysema extraction using thoracic 3-D CT images

NASA Astrophysics Data System (ADS)

Saita, Shinsuke; Kubo, Mitsuru; Kawata, Yoshiki; Niki, Noboru; Nakano, Yasutaka; Ohmatsu, Hironobu; Tominaga, Keigo; Eguchi, Kenji; Moriyama, Noriyuki

2008-03-01

Emphysema patients have the tendency to increase due to aging and smoking. Emphysematous disease destroys alveolus and to repair is impossible, thus early detection is essential. CT value of lung tissue decreases due to the destruction of lung structure. This CT value becomes lower than the normal lung- low density absorption region or referred to as Low Attenuation Area (LAA). So far, the conventional way of extracting LAA by simple thresholding has been proposed. However, the CT value of CT image fluctuates due to the measurement conditions, with various bias components such as inspiration, expiration and congestion. It is therefore necessary to consider these bias components in the extraction of LAA. We removed these bias components and we proposed LAA extraction algorithm. This algorithm has been applied to the phantom image. Then, by using the low dose CT(normal: 30 cases, obstructive lung disease: 26 cases), we extracted early stage LAA and quantitatively analyzed lung lobes using lung structure.

Quantitative assessment of atherosclerotic plaques on (18)F-FDG PET/MRI: comparison with a PET/CT hybrid system.

PubMed

Li, Xiang; Heber, Daniel; Rausch, Ivo; Beitzke, Dietrich; Mayerhoefer, Marius E; Rasul, Sazan; Kreissl, Michael; Mitthauser, Markus; Wadsak, Wolfgang; Hartenbach, Markus; Haug, Alexander; Zhang, Xiaoli; Loewe, Christian; Beyer, Thomas; Hacker, Marcus

2016-07-01

PET with (18)F-FDG has the potential to assess vascular macrophage metabolism. (18)F-FDG is most often used in combination with contrast-enhanced CT to localize increased metabolism to specific arterial lesions. Novel (18)F-FDG PET/MRI hybrid imaging shows high potential for the combined evaluation of atherosclerotic plaques, due to the superior morphological conspicuity of plaque lesions. The purpose of this study was to evaluate the reliability and accuracy of (18)F-FDG PET/MRI uptake quantification compared to PET/CT as a reference standard in patients with carotid atherosclerotic plaques. The study group comprised 34 consecutive oncological patients with carotid plaques who underwent both PET/CT and PET/MRI with (18)F-FDG on the same day. The presence of atherosclerotic plaques was confirmed by 3 T MRI scans. Maximum standardized uptake values (SUVmax) for carotid plaque lesions and the average SUV of the blood pool within the adjacent internal jugular vein were determined and target-to-blood ratios (TBRs, plaque to blood pool) were calculated. Atherosclerotic lesions with maximum colocalized focal FDG uptake were assessed in each patient. SUVmax values of carotid plaque lesions were significantly lower on PET/MRI than on PET/CT (2.3 ± 0.6 vs. 3.1 ± 0.6; P < 0.01), but were significantly correlated between PET/CT and PET/MRI (Spearman's r = 0.67, P < 0.01). In contrast, TBRmax values of plaque lesions were similar on PET/MRI and on PET/CT (2.2 ± 0.3 vs. 2.2 ± 0.3; P = 0.4), and again were significantly correlated between PET/MRI and PET/CT (Spearman's r = 0.73, P < 0.01). Considering the increasing trend in SUVmax and TBRmax values from early to delayed imaging time-points on PET/CT and PET/MRI, respectively, with continuous clearance of radioactivity from the blood, a slight underestimation of TBRmax values may also be expected with PET/MRI compared with PET/CT. SUVmax and TBRmax values are widely accepted reference parameters for estimation of the radioactivity of atherosclerotic plaques on PET/CT. However, due to a systematic underestimation of SUVmax and TBRmax with PET/MRI, the optimal cut-off values indicating the presence of inflamed plaque tissue need to be newly defined for PET/MRI.

MO-DE-207B-10: Impact of Morphologic Characteristics On Radiomics Features From Contast-Enhanced CT for Primary Lung Tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fried, D; Zhang, L; Fave, X

Purpose: Determine the impact of morphologic characteristics (e.g. necrosis, vascular enhancement, and cavitation) on radiomic features from contrast enhanced CT (CE-CT) in primary lung tumors. Methods: We developed an auto-segmentation algorithm to separate lung tumors on contrast-enhanced CT into cavitation (air), necrosis, tissue, and enhancing vessels using a combination of thresholding and region-growing. An auto-segmentation algorithm was also designed to identify necrosis on FDG-PET scans. Wilcoxon rank-sum tests were used to determine if significant differences existed in radiomics features (histogram-uniformity and Laplacian-of-Gaussian average) from 249 patients, found to prognostic in previous work, based on the presence/absence of morphologic features. Featuremore » values were also compared between the original tumor contours and contours excluding a specific morphologic feature. Comparison of necrosis segmentation on CE-CT versus FDG-PET was performed in 78 patients to assess for agreement using the concordance correlation coefficient (CCC). Results: Tumors with cavitation and enhancing vasculature had lower uniformity values (p = 0.001 and p = 0.03, respectively). Tumors with enhancing vasculature and necrosis had higher Laplacian-of-Gaussian average values (measure of “edges” within the tumor) (p < 0.001). Removing these tissue types from regions-of-interest did not drastically alter either radiomic feature value (all scenarios had R{sup 2} > 0.8). This suggests there may be interactions between morphologic characteristics and the radiomic feature value of tumor tissue. Comparison of necrosis volume and percent necrosis volume of tumor were found to have CCC values of 0.85 and 0.76, respectively between CE-CT and FDG-PET segmentation methods. Conclusions: Tumors with enhancing vasculature, necrosis, and cavitation have higher radiomic feature values that are associated with poor prognosis than tumors without these features. Removing these tissue types from quantitative assessment did not drastically impact radiomic feature values. High reproducibility of CE-CT segmented necrosis compared to FDG-PET segmented necrosis provides a reasonable validation of segmentation accuracy on CE-CT.« less

[Radiation exposure during spiral-CT of the paranasal sinuses].

PubMed

Dammann, F; Momino-Traserra, E; Remy, C; Pereira, P L; Baumann, I; Koitschev, A; Claussen, C D

2000-03-01

Determination of the radiation doses in spiral CT of the paranasal sinuses using a variety of mAs values and scan protocols. CT examinations of the paranasal sinuses were performed using an Alderson-Rando phantom. Radiation dose was determined by LiF-TLD at the level of high risk organs in the head and neck region for combinations of different scan parameters (2/3, 3/3, 3/4 mm) and decreasing charges (200, 150, 100, 50, 25 mAs) on a spiral CT. Additional measurements were performed on three other CT scanners using the 2/3 mm protocol at 50 mAs, and a single slice technique (5/5 mm) on one scanner. The lowest dose values found were 1.88 mGy for the eye lenses, 1.35 mGy for the parotid gland, 0.03 mGy for the thyroid gland and 0.1 mGy for the medulla oblongata using 2 mm collimation and 3 mm table feed at 25 mAs. Maximal dose values resulted using the 3/3 mm protocol at 200 mAs (31.00 mGy for the eye lense, 0.65 mGy for the thyroid gland). There were no significant differences found between the different CT scanners. Using up-to-date CT scanners, radiation exposure may be reduced by a factor of 15-20 compared to that of conventional CT technique. Thus, the exposure of the eye lens comes to only a thousandth of the value supposedly inducing a cataract, as published by the ICRP.

Benign and malignant skull-involved lesions: discriminative value of conventional CT and MRI combined with diffusion-weighted MRI.

PubMed

Tu, Zhanhai; Xiao, Zebin; Zheng, Yingyan; Huang, Hongjie; Yang, Libin; Cao, Dairong

2018-01-01

Background Little is known about the value of computed tomography (CT) and magnetic resonance imaging (MRI) combined with diffusion-weighted imaging (DWI) in distinguishing malignant from benign skull-involved lesions. Purpose To evaluate the discriminative value of DWI combined with conventional CT and MRI for differentiating between benign and malignant skull-involved lesions. Material and Methods CT and MRI findings of 58 patients with pathologically proven skull-involved lesions (43 benign and 15 malignant) were retrospectively reviewed. Conventional CT and MRI characteristics and apparent diffusion coefficient (ADC) value of the two groups were evaluated and compared. Multivariate logistic regression and receiver operating characteristic (ROC) curve analyses were performed to assess the differential performance of each parameter separately and together. Results The presence of cortical defects or break-through and ill-defined margins were associated with malignant skull-involved lesions (both P < 0.05). Malignant skull-involved lesions demonstrated a significantly lower ADC ( P = 0.016) than benign lesions. ROC curve analyses indicated that a combination of CT, MRI, and DWI with an ADC ≤ 0.703 × 10 -3 mm 2 /s showed optimal sensitivity, while DWI along showed optimal specificity of 88.4% in differentiating between benign and malignant skull-involved lesions. Conclusion The combination of CT, MRI, and DWI can help to differentiate malignant from benign skull-involved lesions. CT + MRI + DWI offers optimal sensitivity, while DWI offers optimal specificity.

Concurrent chemotherapy and pelvic radiation therapy compared with pelvic radiation therapy alone as adjuvant therapy after radical surgery in high-risk early-stage cancer of the cervix.

PubMed

Peters, W A; Liu, P Y; Barrett, R J; Stock, R J; Monk, B J; Berek, J S; Souhami, L; Grigsby, P; Gordon, W; Alberts, D S

2000-04-01

To determine whether the addition of cisplatin-based chemotherapy (CT) to pelvic radiation therapy (RT) will improve the survival of early-stage, high-risk patients with cervical carcinoma. Patients with clinical stage IA(2), IB, and IIA carcinoma of the cervix, initially treated with radical hysterectomy and pelvic lymphadenectomy, and who had positive pelvic lymph nodes and/or positive margins and/or microscopic involvement of the parametrium were eligible for this study. Patients were randomized to receive RT or RT + CT. Patients in each group received 49.3 GY RT in 29 fractions to a standard pelvic field. Chemotherapy consisted of bolus cisplatin 70 mg/m(2) and a 96-hour infusion of fluorouracil 1,000 mg/m(2)/d every 3 weeks for four cycles, with the first and second cycles given concurrent to RT. Between 1991 and 1996, 268 patients were entered onto the study. Two hundred forty-three patients were assessable (127 RT + CT patients and 116 RT patients). Progression-free and overall survival are significantly improved in the patients receiving CT. The hazard ratios for progression-free survival and overall survival in the RT only arm versus the RT + CT arm are 2.01 (P =.003) and 1.96 (P =. 007), respectively. The projected progression-free survivals at 4 years is 63% with RT and 80% with RT + CT. The projected overall survival rate at 4 years is 71% with RT and 81% with RT + CT. Grades 3 and 4 hematologic and gastrointestinal toxicity were more frequent in the RT + CT group. The addition of concurrent cisplatin-based CT to RT significantly improves progression-free and overall survival for high-risk, early-stage patients who undergo radical hysterectomy and pelvic lymphadenectomy for carcinoma of the cervix.

Comparison of Simplexa HSV 1 & 2 PCR with culture, immunofluorescence, and laboratory-developed TaqMan PCR for detection of herpes simplex virus in swab specimens.

PubMed

Gitman, Melissa R; Ferguson, David; Landry, Marie L

2013-11-01

The Simplexa HSV 1 & 2 direct PCR assay was compared with conventional cell culture, cytospin-enhanced direct fluorescent antibody (DFA), and a laboratory-developed real-time TaqMan PCR (LDT HSV PCR) using extracted nucleic acid for the detection of herpes simplex virus (HSV) in dermal, genital, mouth, ocular, and other swab samples. One hundred seventy-one swabs were tested prospectively, and 58 were positive for HSV (34 HSV-1 and 24 HSV-2). Cytospin-DFA detected 50 (86.2%), conventional cell culture 51 (87.9%), Simplexa direct 55 (94.8%), and LDT HSV PCR 57 (98.3%) of 58 true positives. Simplexa direct detected more positives than DFA and culture, but the differences were not significant (P = 0.0736 and P = 0.3711, respectively, by the McNemar test). Samples that were positive by all methods (n = 48) were strong positives (LDT cycle threshold [CT] value, 14.4 to 26.1). One strongly positive sample was falsely negative by LDT HSV PCR due to a failure of TaqMan probe binding. Three samples falsely negative by Simplexa direct had high CT values by LDT HSV PCR (LDT CT, 35.8 to 38.2). Omission of the DNA extraction step by Simplexa direct led to a drop in sensitivity compared to the sensitivity of LDT HSV PCR using extracted samples (94.8% versus 98.3%, respectively), but the difference was not significant (P = 0.6171). Simplexa HSV 1 & 2 direct PCR was the most expensive but required the least training of the assays used, had the lowest hands-on time and fastest assay time (75 min, versus 3 h by LDT HSV PCR), and provided the HSV type.

Comparison of Simplexa HSV 1 & 2 PCR with Culture, Immunofluorescence, and Laboratory-Developed TaqMan PCR for Detection of Herpes Simplex Virus in Swab Specimens

PubMed Central

Gitman, Melissa R.; Ferguson, David

2013-01-01

The Simplexa HSV 1 & 2 direct PCR assay was compared with conventional cell culture, cytospin-enhanced direct fluorescent antibody (DFA), and a laboratory-developed real-time TaqMan PCR (LDT HSV PCR) using extracted nucleic acid for the detection of herpes simplex virus (HSV) in dermal, genital, mouth, ocular, and other swab samples. One hundred seventy-one swabs were tested prospectively, and 58 were positive for HSV (34 HSV-1 and 24 HSV-2). Cytospin-DFA detected 50 (86.2%), conventional cell culture 51 (87.9%), Simplexa direct 55 (94.8%), and LDT HSV PCR 57 (98.3%) of 58 true positives. Simplexa direct detected more positives than DFA and culture, but the differences were not significant (P = 0.0736 and P = 0.3711, respectively, by the McNemar test). Samples that were positive by all methods (n = 48) were strong positives (LDT cycle threshold [CT] value, 14.4 to 26.1). One strongly positive sample was falsely negative by LDT HSV PCR due to a failure of TaqMan probe binding. Three samples falsely negative by Simplexa direct had high CT values by LDT HSV PCR (LDT CT, 35.8 to 38.2). Omission of the DNA extraction step by Simplexa direct led to a drop in sensitivity compared to the sensitivity of LDT HSV PCR using extracted samples (94.8% versus 98.3%, respectively), but the difference was not significant (P = 0.6171). Simplexa HSV 1 & 2 direct PCR was the most expensive but required the least training of the assays used, had the lowest hands-on time and fastest assay time (75 min, versus 3 h by LDT HSV PCR), and provided the HSV type. PMID:24006008

Clinical evaluation of the Abbott RealTime MTB Assay for direct detection of Mycobacterium tuberculosis-complex from respiratory and non-respiratory samples.

PubMed

Hinić, Vladimira; Feuz, Kinga; Turan, Selda; Berini, Andrea; Frei, Reno; Pfeifer, Karin; Goldenberger, Daniel

2017-05-01

Rapid and reliable diagnosis is crucial for correct management of tuberculosis. The Abbott RealTime MTB Assay represents a novel qualitative real-time PCR assay for direct detection of M. tuberculosis-complex (MTB) DNA from respiratory samples. The test targets two highly conserved sequences, the multi-copy insertion element IS6110 and the protein antigen B (PAB) gene of MTB, allowing even the detection of IS6610-deficient strains. We evaluated this commercial diagnostic test by analyzing 200 respiratory and, for the first time, 87 non-respiratory clinical specimens from our tertiary care institution and compared its results to our IS6110-based in-house real-time PCR for MTB as well as MTB culture. Overall sensitivity for Abbott RealTime MTB was 100% (19/19) in smear positive and 87.5% (7/8) in smear negative specimens, while the specificity of the assay was 100% (260/260). For both non-respiratory smear positive and smear negative specimens Abbott RealTime MTB tests showed 100% (8/8) sensitivity and 100% (8/8) specificity. Cycle threshold (Ct) value analysis of 16 MTB positive samples showed a slightly higher Ct value of the Abbott RealTime MTB test compared to our in-house MTB assay (mean delta Ct = 2.55). In conclusion, the performance of the new Abbott RealTime MTB Assay was highly similar to culture and in-house MTB PCR. We document successful analysis of 87 non-respiratory samples with the highly automated Abbott RealTime MTB test with no inhibition observed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparative Evaluation of Three Homogenization Methods for Isolating Middle East Respiratory Syndrome Coronavirus Nucleic Acids From Sputum Samples for Real-Time Reverse Transcription PCR.

PubMed

Sung, Heungsup; Yong, Dongeun; Ki, Chang Seok; Kim, Jae Seok; Seong, Moon Woo; Lee, Hyukmin; Kim, Mi Na

2016-09-01

Real-time reverse transcription PCR (rRT-PCR) of sputum samples is commonly used to diagnose Middle East respiratory syndrome coronavirus (MERS-CoV) infection. Owing to the difficulty of extracting RNA from sputum containing mucus, sputum homogenization is desirable prior to nucleic acid isolation. We determined optimal homogenization methods for isolating viral nucleic acids from sputum. We evaluated the following three sputum-homogenization methods: proteinase K and DNase I (PK-DNase) treatment, phosphate-buffered saline (PBS) treatment, and N-acetyl-L-cysteine and sodium citrate (NALC) treatment. Sputum samples were spiked with inactivated MERS-CoV culture isolates. RNA was extracted from pretreated, spiked samples using the easyMAG system (bioMérieux, France). Extracted RNAs were then subjected to rRT-PCR for MERS-CoV diagnosis (DiaPlex Q MERS-coronavirus, SolGent, Korea). While analyzing 15 spiked sputum samples prepared in technical duplicate, false-negative results were obtained with five (16.7%) and four samples (13.3%), respectively, by using the PBS and NALC methods. The range of threshold cycle (Ct) values observed when detecting upE in sputum samples was 31.1-35.4 with the PK-DNase method, 34.7-39.0 with the PBS method, and 33.9-38.6 with the NALC method. Compared with the control, which were prepared by adding a one-tenth volume of 1:1,000 diluted viral culture to PBS solution, the ranges of Ct values obtained by the PBS and NALC methods differed significantly from the mean control Ct of 33.2 (both P<0.0001). The PK-DNase method is suitable for homogenizing sputum samples prior to RNA extraction.

Comparative Evaluation of Three Homogenization Methods for Isolating Middle East Respiratory Syndrome Coronavirus Nucleic Acids From Sputum Samples for Real-Time Reverse Transcription PCR

PubMed Central

Yong, Dongeun; Ki, Chang-Seok; Kim, Jae-Seok; Seong, Moon-Woo; Lee, Hyukmin

2016-01-01

Background Real-time reverse transcription PCR (rRT-PCR) of sputum samples is commonly used to diagnose Middle East respiratory syndrome coronavirus (MERS-CoV) infection. Owing to the difficulty of extracting RNA from sputum containing mucus, sputum homogenization is desirable prior to nucleic acid isolation. We determined optimal homogenization methods for isolating viral nucleic acids from sputum. Methods We evaluated the following three sputum-homogenization methods: proteinase K and DNase I (PK-DNase) treatment, phosphate-buffered saline (PBS) treatment, and N-acetyl-L-cysteine and sodium citrate (NALC) treatment. Sputum samples were spiked with inactivated MERS-CoV culture isolates. RNA was extracted from pretreated, spiked samples using the easyMAG system (bioMérieux, France). Extracted RNAs were then subjected to rRT-PCR for MERS-CoV diagnosis (DiaPlex Q MERS-coronavirus, SolGent, Korea). Results While analyzing 15 spiked sputum samples prepared in technical duplicate, false-negative results were obtained with five (16.7%) and four samples (13.3%), respectively, by using the PBS and NALC methods. The range of threshold cycle (Ct) values observed when detecting upE in sputum samples was 31.1–35.4 with the PK-DNase method, 34.7–39.0 with the PBS method, and 33.9–38.6 with the NALC method. Compared with the control, which were prepared by adding a one-tenth volume of 1:1,000 diluted viral culture to PBS solution, the ranges of Ct values obtained by the PBS and NALC methods differed significantly from the mean control Ct of 33.2 (both P<0.0001). Conclusions The PK-DNase method is suitable for homogenizing sputum samples prior to RNA extraction. PMID:27374711

Advances in Pancreatic CT Imaging.

PubMed

Almeida, Renata R; Lo, Grace C; Patino, Manuel; Bizzo, Bernardo; Canellas, Rodrigo; Sahani, Dushyant V

2018-07-01

The purpose of this article is to discuss the advances in CT acquisition and image postprocessing as they apply to imaging the pancreas and to conceptualize the role of radiogenomics and machine learning in pancreatic imaging. CT is the preferred imaging modality for assessment of pancreatic diseases. Recent advances in CT (dual-energy CT, CT perfusion, CT volumetry, and radiogenomics) and emerging computational algorithms (machine learning) have the potential to further increase the value of CT in pancreatic imaging.

An automated A-value measurement tool for accurate cochlear duct length estimation.

PubMed

Iyaniwura, John E; Elfarnawany, Mai; Ladak, Hanif M; Agrawal, Sumit K

2018-01-22

There has been renewed interest in the cochlear duct length (CDL) for preoperative cochlear implant electrode selection and postoperative generation of patient-specific frequency maps. The CDL can be estimated by measuring the A-value, which is defined as the length between the round window and the furthest point on the basal turn. Unfortunately, there is significant intra- and inter-observer variability when these measurements are made clinically. The objective of this study was to develop an automated A-value measurement algorithm to improve accuracy and eliminate observer variability. Clinical and micro-CT images of 20 cadaveric cochleae specimens were acquired. The micro-CT of one sample was chosen as the atlas, and A-value fiducials were placed onto that image. Image registration (rigid affine and non-rigid B-spline) was applied between the atlas and the 19 remaining clinical CT images. The registration transform was applied to the A-value fiducials, and the A-value was then automatically calculated for each specimen. High resolution micro-CT images of the same 19 specimens were used to measure the gold standard A-values for comparison against the manual and automated methods. The registration algorithm had excellent qualitative overlap between the atlas and target images. The automated method eliminated the observer variability and the systematic underestimation by experts. Manual measurement of the A-value on clinical CT had a mean error of 9.5 ± 4.3% compared to micro-CT, and this improved to an error of 2.7 ± 2.1% using the automated algorithm. Both the automated and manual methods correlated significantly with the gold standard micro-CT A-values (r = 0.70, p < 0.01 and r = 0.69, p < 0.01, respectively). An automated A-value measurement tool using atlas-based registration methods was successfully developed and validated. The automated method eliminated the observer variability and improved accuracy as compared to manual measurements by experts. This open-source tool has the potential to benefit cochlear implant recipients in the future.

Differentiation and diagnosis of benign and malignant testicular lesions using 18F-FDG PET/CT.

PubMed

Shao, Dan; Gao, Qiang; Tian, Xu-Wei; Wang, Si-Yun; Liang, Chang-Hong; Wang, Shu-Xia

2017-08-01

The purpose of this study was to evaluate the differential diagnostic value of 18 F-fluorodeoxy glucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) for benign and malignant testicular lesions. The PET/CT scans of 53 patients with testicular lesions confirmed by biopsy or surgical pathology were retrospectively analyzed. There were 32 cases of malignant tumors and 21 cases of benign lesions. Differences in the maximum standardized uptake value (SUVmax) measurements and the SUVmax lesion/background ratios between benign and malignant lesions were analyzed. The diagnostic value of this PET/CT modality for the differential diagnosis of benign versus malignant testicular lesions was calculated. The differences in the SUVmax measurements and the SUVmax lesion/background ratios between benign and malignant lesions were statistically significant (SUVmax: Z=-4.295, p=0.000; SUVmax lesion/background ratio: Z=-5.219, p=0.000); specifically, both of these indicators were higher in malignant lesions compared to benign lesions. An SUVmax of 3.75 was the optimal cutoff value to differentiate between benign and malignant testicular lesions. The diagnostic sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of this PET/CT modality in the differential diagnosis of benign versus malignant testicular lesions were 90.6%, 80.9%, 86.8%, 87.9%, and 85.0%, respectively. 18 F-FDG PET/CT can accurately identify benign and malignant testicular lesions. Copyright © 2017 Elsevier B.V. All rights reserved.

Reliability of voxel gray values in cone beam computed tomography for preoperative implant planning assessment.

PubMed

Parsa, Azin; Ibrahim, Norliza; Hassan, Bassam; Motroni, Alessandro; van der Stelt, Paul; Wismeijer, Daniel

2012-01-01

To assess the reliability of cone beam computed tomography (CBCT) voxel gray value measurements using Hounsfield units (HU) derived from multislice computed tomography (MSCT) as a clinical reference (gold standard). Ten partially edentulous human mandibular cadavers were scanned by two types of computed tomography (CT) modalities: multislice CT and cone beam CT. On MSCT scans, eight regions of interest (ROI) designating the site for preoperative implant placement were selected in each mandible. The datasets from both CT systems were matched using a three-dimensional (3D) registration algorithm. The mean voxel gray values of the region around the implant sites were compared between MSCT and CBCT. Significant differences between the mean gray values obtained by CBCT and HU by MSCT were found. In all the selected ROIs, CBCT showed higher mean values than MSCT. A strong correlation (R=0.968) between mean voxel gray values of CBCT and mean HU of MSCT was determined. Voxel gray values from CBCT deviate from actual HU units. However, a strong linear correlation exists, which may permit deriving actual HU units from CBCT using linear regression models.

18F-FDG PET/CT in differentiating malignant from benign origins of obstructive jaundice.

PubMed

Wang, Shao-Bo; Wu, Hu-Bing; Wang, Quan-Shi; Zhou, Wen-Lan; Tian, Ying; Ji, Yun-Hai; Lv, Liang

2015-10-01

The various origins of obstructive jaundice make the diagnosis of the disease difficult. This study was undertaken to evaluate the role of 18F-FDG PET/CT in differentiating malignant from benign origins of obstructive jaundice and to quantify the added value of 18F-FDG PET/CT over conventional imaging (enhanced CT and/or MRI). Eighty-five patients with obstructive jaundice who underwent 18F-FDG PET/CT within 2 weeks after enhanced CT and/or MRI were reviewed retrospectively. All 18F-FDG PET/CT images were independently evaluated by 2 nuclear medicine physicians who were unaware of other imaging data; differences were resolved by consensus of the physicians. All conventional imaging interpretations, according to the medical records, were reviewed by 2 radiologists to determine the potential value. Final diagnoses were based on histological or surgical findings. Sixty-six patients were diagnosed with malignancies, and 19 patients with benign lesions. The maximum standardized uptake values for malignant and benign lesions causing biliary obstruction were 8.2+/-4.4 and 4.0+/-5.0, respectively (P<0.05). The sensitivity, specificity, and overall accuracy for differentiating malignant from benign origins with 18F-FDG PET/CT were 86.4% (57/66), 73.7% (14/19), and 83.5% (71/85), respectively. 18F-FDG PET/CT in conjunction with conventional imaging changed the sensitivity, specificity, and overall accuracy of conventional imaging alone from 75.8% (50/66) to 95.5% (63/66) (P<0.05), 68.4% (13/19) to 57.9% (11/19) (P>0.05), and 74.1% (63/85) to 87.1% (74/85) (P<0.05), respectively. 18F-FDG PET/CT is of great value in differentiating malignant from benign origins of obstructive jaundice and is a useful adjuvant to conventional imaging. 18F-FDG PET/CT should be recommended for further etiological clarification.

Clinical Significance of Fluorine-18-fluorodeoxyglucose Positron Emission Tomography/computed Tomography in the Follow-up of Colorectal Cancer: Searching off Approaches Increasing Specificity for Detection of Recurrence

PubMed Central

Okuyucu, Kursat; Hancerliogulları, Oguz; Alagoz, Engin; San, Huseyin; Arslan, Nuri

2017-01-01

Abstract Background Nearly 40% of colorectal cancer (CRC) recurs within 2 years after resection of primary tumor. Imaging with fluorine-18-fluorodeoxyglucose (l8F-FDG) positron emission tomography/computed tomography (PET/CT) is the most recent modality and often applied for the evaluation of metastatic spread during the follow-up period. Our goal was to study the diagnostic importance of 18F-FDG-PET/CT data of maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG) and the difference of SUVmax on dual-time imaging in CRC. Patients and methods We examined the SUVmax value of lesions on control or restaging 18F-FDG-PET/CT of 53 CRC patients. All lesions with increased SUVmax values were confirmed by colonoscopy or histopathology. We compared PET/CT results with conventional imaging modalities (CT, MRI) and tumor markers (carbohydrate antigen 19-9 [Ca 19-9], carcinoembryonic antigen [CEA]). Results Mean SUVmax was 6.9 ± 5.6 in benign group, 12.7 ± 6.1 in malignant group. Mean TLG values of malignant group and benign group were 401 and 148, respectively. 18F-FDG-PET/CT was truely positive in 48% of patients with normal Ca 19-9 or CEA levels and truely negative in 10% of cases with elevated Ca 19-9 or CEA. CT or MRI detected suspicious malignancy in 32% of the patients and 18F-FDG-PET/CT was truely negative in 35% of these cases. We found the most important and striking statistical difference of TLG value between the groups with benign and recurrent disease. Conclusions Although SUVmax is a strong metabolic parameter (p = 0.008), TLG seems to be the best predictor in recurrence of CRC (p = 0.001); both are increasing the specificity of 18F-FDG-PET/CT. PMID:29333115

Clinical Significance of Fluorine-18-fluorodeoxyglucose Positron Emission Tomography/computed Tomography in the Follow-up of Colorectal Cancer: Searching off Approaches Increasing Specificity for Detection of Recurrence.

PubMed

Ince, Semra; Okuyucu, Kursat; Hancerliogulları, Oguz; Alagoz, Engin; San, Huseyin; Arslan, Nuri

2017-12-01

Nearly 40% of colorectal cancer (CRC) recurs within 2 years after resection of primary tumor. Imaging with fluorine-18-fluorodeoxyglucose ( l8 F-FDG) positron emission tomography/computed tomography (PET/CT) is the most recent modality and often applied for the evaluation of metastatic spread during the follow-up period. Our goal was to study the diagnostic importance of 18 F-FDG-PET/CT data of maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG) and the difference of SUVmax on dual-time imaging in CRC. We examined the SUVmax value of lesions on control or restaging 18 F-FDG-PET/CT of 53 CRC patients. All lesions with increased SUVmax values were confirmed by colonoscopy or histopathology. We compared PET/CT results with conventional imaging modalities (CT, MRI) and tumor markers (carbohydrate antigen 19-9 [Ca 19-9], carcinoembryonic antigen [CEA]). Mean SUVmax was 6.9 ± 5.6 in benign group, 12.7 ± 6.1 in malignant group. Mean TLG values of malignant group and benign group were 401 and 148, respectively. 18 F-FDG-PET/CT was truely positive in 48% of patients with normal Ca 19-9 or CEA levels and truely negative in 10% of cases with elevated Ca 19-9 or CEA. CT or MRI detected suspicious malignancy in 32% of the patients and 18 F-FDG-PET/CT was truely negative in 35% of these cases. We found the most important and striking statistical difference of TLG value between the groups with benign and recurrent disease. Although SUVmax is a strong metabolic parameter (p = 0.008), TLG seems to be the best predictor in recurrence of CRC (p = 0.001); both are increasing the specificity of 18 F-FDG-PET/CT.

Method of Individual Adjustment for 3D CT Analysis: Linear Measurement.

PubMed

Kim, Dong Kyu; Choi, Dong Hun; Lee, Jeong Woo; Yang, Jung Dug; Chung, Ho Yun; Cho, Byung Chae; Choi, Kang Young

2016-01-01

Introduction . We aim to regularize measurement values in three-dimensional (3D) computed tomography (CT) reconstructed images for higher-precision 3D analysis, focusing on length-based 3D cephalometric examinations. Methods . We measure the linear distances between points on different skull models using Vernier calipers (real values). We use 10 differently tilted CT scans for 3D CT reconstruction of the models and measure the same linear distances from the picture archiving and communication system (PACS). In both cases, each measurement is performed three times by three doctors, yielding nine measurements. The real values are compared with the PACS values. Each PACS measurement is revised based on the display field of view (DFOV) values and compared with the real values. Results . The real values and the PACS measurement changes according to tilt value have no significant correlations ( p > 0.05). However, significant correlations appear between the real values and DFOV-adjusted PACS measurements ( p < 0.001). Hence, we obtain a correlation expression that can yield real physical values from PACS measurements. The DFOV value intervals for various age groups are also verified. Conclusion . Precise confirmation of individual preoperative length and precise analysis of postoperative improvements through 3D analysis is possible, which is helpful for facial-bone-surgery symmetry correction.

Role of 18F-FDG PET/CT in the Carcinoma of the Uterus: A Review of Literature

PubMed Central

Musto, Alessandra; Grassetto, Gaia; Marzola, Maria Cristina; Chondrogiannis, Sotirios; Maffione, Anna Margherita; Rampin, Lucia; Fuster, David; Giammarile, Francesco; Colletti, Patrick M.

2014-01-01

In the present review we reported the value of 18F-fluorodeoxyglucose (FDG) PET/CT in face of uterine cancer, in terms of sensitivity, specificity and accuracy. Moreover, we made a comparison with the other imaging techniques currently used to evacuate these tumors including contrast-enhanced CT, contrast enhanced-MRI and transvaginal ultrasonography. FDG PET/CT has been reported to be of particular value in detecting occult metastatic lesions, in prediction of response to treatment and as a pro-gnostic factor. PMID:25323881

Feasibility of dual-energy computed tomography in radiation therapy planning

NASA Astrophysics Data System (ADS)

Sheen, Heesoon; Shin, Han-Back; Cho, Sungkoo; Cho, Junsang; Han, Youngyih

2017-12-01

In this study, the noise level, effective atomic number ( Z eff), accuracy of the computed tomography (CT) number, and the CT number to the relative electron density EDconversion curve were estimated for virtual monochromatic energy and polychromatic energy. These values were compared to the theoretically predicted values to investigate the feasibility of the use of dual-energy CT in routine radiation therapy planning. The accuracies of the parameters were within the range of acceptability. These results can serve as a stepping stone toward the routine use of dual-energy CT in radiotherapy planning.

Shunting normal pressure hydrocephalus: the predictive value of combined clinical and CT data.

PubMed

Vanneste, J; Augustijn, P; Tan, W F; Dirven, C

1993-03-01

The value of an ordinal global scale derived from combined clinical and CT data (clin/CT scale) to predict the clinical outcome in 112 patients shunted for presumed normal pressure hydrocephalus (NPH) was analysed. The clinical data were retrospectively collected, all CT scans were re-evaluated, and the clin/CT scale was determined blind to the results of further ancillary tests and to the post-surgical outcome. The scale ranked three classes of prediction: on the basis of clinical and CT characteristics, improvement after shunting was probable, possible, or improbable. The predictive value of the clin/CT scale for the subgroup of communicating NPH was established for two different strategies, depending on the strictness of selection criteria for shunting. In the subgroup of patients with presumed communicating NPH, the prevalence of shunt responsiveness was 29%; the best strategy was to shunt only patients with probable shunt-responsive NPH: the sensitivity was 0.54, the specificity 0.84, and the predictive accuracy 0.75, with a limited number of ineffective shunts (11%) and missed improvements (13%). The study illustrates its need to assess the pre-test probability of NPH based on combined clinical and CT data, before establishing the clinical usefulness of an ancillary test.

Shunting normal pressure hydrocephalus: the predictive value of combined clinical and CT data.

PubMed Central

Vanneste, J; Augustijn, P; Tan, W F; Dirven, C

1993-01-01

The value of an ordinal global scale derived from combined clinical and CT data (clin/CT scale) to predict the clinical outcome in 112 patients shunted for presumed normal pressure hydrocephalus (NPH) was analysed. The clinical data were retrospectively collected, all CT scans were re-evaluated, and the clin/CT scale was determined blind to the results of further ancillary tests and to the post-surgical outcome. The scale ranked three classes of prediction: on the basis of clinical and CT characteristics, improvement after shunting was probable, possible, or improbable. The predictive value of the clin/CT scale for the subgroup of communicating NPH was established for two different strategies, depending on the strictness of selection criteria for shunting. In the subgroup of patients with presumed communicating NPH, the prevalence of shunt responsiveness was 29%; the best strategy was to shunt only patients with probable shunt-responsive NPH: the sensitivity was 0.54, the specificity 0.84, and the predictive accuracy 0.75, with a limited number of ineffective shunts (11%) and missed improvements (13%). The study illustrates its need to assess the pre-test probability of NPH based on combined clinical and CT data, before establishing the clinical usefulness of an ancillary test. PMID:8459240

Reliability of transpulmonary pressure-time curve profile to identify tidal recruitment/hyperinflation in experimental unilateral pleural effusion.

PubMed

Formenti, P; Umbrello, M; Graf, J; Adams, A B; Dries, D J; Marini, J J

2017-08-01

The stress index (SI) is a parameter that characterizes the shape of the airway pressure-time profile (P/t). It indicates the slope progression of the curve, reflecting both lung and chest wall properties. The presence of pleural effusion alters the mechanical properties of the respiratory system decreasing transpulmonary pressure (Ptp). We investigated whether the SI computed using Ptp tracing would provide reliable insight into tidal recruitment/overdistention during the tidal cycle in the presence of unilateral effusion. Unilateral pleural effusion was simulated in anesthetized, mechanically ventilated pigs. Respiratory system mechanics and thoracic computed tomography (CT) were studied to assess P/t curve shape and changes in global lung aeration. SI derived from airway pressure (Paw) was compared with that calculated by Ptp under the same conditions. These results were themselves compared with quantitative CT analysis as a gold standard for tidal recruitment/hyperinflation. Despite marked changes in tidal recruitment, mean values of SI computed either from Paw or Ptp were remarkably insensitive to variations of PEEP or condition. After the instillation of effusion, SI indicates a preponderant over-distension effect, not detected by CT. After the increment in PEEP level, the extent of CT-determined tidal recruitment suggest a huge recruitment effect of PEEP as reflected by lung compliance. Both SI in this case were unaffected. We showed that the ability of SI to predict tidal recruitment and overdistension was significantly reduced in a model of altered chest wall-lung relationship, even if the parameter was computed from the Ptp curve profile.

Effect of introducing legumes containing condensed tannins in an orchardgrass diet on forage nutritive value and enteric methane output in continuous culture

USDA-ARS?s Scientific Manuscript database

Legumes containing condensed tannins (CT) have been shown to reduce enteric CH4 in ruminants; however, research is lacking on how increased CT levels affect forage nutritive value and CH4 output. A 4-unit, dual-flow continuous culture fermentor system was used to assess CH4 output of CT legumes in a...

Comparison of 68Ga-PSMA-11 PET-CT with mpMRI for preoperative lymph node staging in patients with intermediate to high-risk prostate cancer.

PubMed

Zhang, Qing; Zang, Shiming; Zhang, Chengwei; Fu, Yao; Lv, Xiaoyu; Zhang, Qinglei; Deng, Yongming; Zhang, Chuan; Luo, Rui; Zhao, Xiaozhi; Wang, Wei; Wang, Feng; Guo, Hongqian

2017-11-07

To evaluate the diagnostic value of 68 Ga-PSMA-11 PET-CT with multiparametric magnetic resonance imaging (mpMRI) for lymph node (LN) staging in patients with intermediate- to high-risk prostate cancer (PCa) undergoing radical prostatectomy (RP) with pelvic lymph node dissection (PLND). We retrospectively identified 42 consecutive patients with intermediate- to high-risk PCa according to D'Amico and without concomitant cancer. Preoperative 68 Ga-PSMA-11 PET-CT, pelvic mpMRI and subsequent robot assisted laparoscopic RP with PLND were performed in all patients. Among 42 patients assessed, the preoperative PSA value, Gleason score, pT stage and intraprostatic PCa volume of patients with LN metastases were all significantly higher than those without metastases (P = 0.029, 0.028, 0.004, respectively). The average maximum standardized uptake value (SUV) of 68 Ga-PSMA-11 PET-CT positive PCa of patients with or without LN metastases were 13.10 (range 6.12-51.75) and 7.22 (range 5.4-11.2), respectively (P < 0.001). 68 Ga-PSMA-11 PET-CT and pelvic mpMRI had the ability of succeed on preoperative definite accurate diagnosis and accurate localization of primary PCa in all 42 patients. Fifteen patients (35.71%) had a pN1 stage. 51 positive LN were found. Both 68 Ga-PSMA-11 PET-CT and pelvic mpMRI displayed brillient patient-based and region-based sensitivity, specificity, negative predictive value and positive predictive value. There was no statistical difference for the detection of LNMs according to the diameter of the LNMs between 68 Ga-PSMA-11 PET-CT and mpMRI in this study. Both 68 Ga-PSMA-11 PET-CT and mpMRI performed great value for LN staging in patients with intermediate- to high-risk PCa undergoing RP with PLND. However, despite excellent performance of 68 Ga-PSMA-11 PET-CT, it cannot replace mpMRI that remains excellent for lymph node staging.

Comparison of CT-derived Ventilation Maps with Deposition Patterns of Inhaled Microspheres in Rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacob, Rick E.; Lamm, W. J.; Einstein, Daniel R.

2015-04-01

Purpose: Computer models for inhalation toxicology and drug-aerosol delivery studies rely on ventilation pattern inputs for predictions of particle deposition and vapor uptake. However, changes in lung mechanics due to disease can impact airflow dynamics and model results. It has been demonstrated that non-invasive, in vivo, 4DCT imaging (3D imaging at multiple time points in the breathing cycle) can be used to map heterogeneities in ventilation patterns under healthy and disease conditions. The purpose of this study was to validate ventilation patterns measured from CT imaging by exposing the same rats to an aerosol of fluorescent microspheres (FMS) and examiningmore » particle deposition patterns using cryomicrotome imaging. Materials and Methods: Six male Sprague-Dawley rats were intratracheally instilled with elastase to a single lobe to induce a heterogeneous disease. After four weeks, rats were imaged over the breathing cycle by CT then immediately exposed to an aerosol of ~1µm FMS for ~5 minutes. After the exposure, the lungs were excised and prepared for cryomicrotome imaging, where a 3D image of FMS deposition was acquired using serial sectioning. Cryomicrotome images were spatially registered to match the live CT images to facilitate direct quantitative comparisons of FMS signal intensity with the CT-based ventilation maps. Results: Comparisons of fractional ventilation in contiguous, non-overlapping, 3D regions between CT-based ventilation maps and FMS images showed strong correlations in fractional ventilation (r=0.888, p<0.0001). Conclusion: We conclude that ventilation maps derived from CT imaging are predictive of the 1µm aerosol deposition used in ventilation-perfusion heterogeneity inhalation studies.« less

Effective and organ doses from common CT examinations in one general hospital in Tehran, Iran

NASA Astrophysics Data System (ADS)

Khoramian, Daryoush; Hashemi, Bijan

2017-09-01

Purpose: It is well known that the main portion of artificial sources of ionizing radiation to human results from X-ray imaging techniques. However, reports carried out in various countries have indicated that most of their cumulative doses from artificial sources are due to CT examinations. Hence assessing doses resulted from CT examinations is highly recommended by national and international radiation protection agencies. The aim of this research has been to estimate the effective and organ doses in an average human according to 103 and 60 ICRP tissue weighting factor for six common protocols of Multi-Detector CT (MDCT) machine in a comprehensive training general hospital in Tehran/Iran. Methods: To calculate the patients' effective dose, the CT-Expo2.2 software was used. Organs/tissues and effective doses were determined for about 20 patients (totally 122 patients) for every one of six typical CT protocols of the head, neck, chest, abdomen-pelvis, pelvis and spine exams. In addition, the CT dosimetry index (CTDI) was measured in the standard 16 and 32 cm phantoms by using a calibrated pencil ionization chamber for the six protocols and by taking the average value of CT scan parameters used in the hospital compared with the CTDI values displayed on the console device of the machine. Results: The values of the effective dose based on the ICRP 103 tissue weighting factor were: 0.6, 2.0, 3.2, 4.2, 2.8, and 3.9 mSv and based on the ICRP 60 tissue weighting factor were: 0.9, 1.4, 3, 7.9, 4.8 and 5.1 mSv for the head, neck, chest, abdomen-pelvis, pelvis, spine CT exams respectively. Relative differences between those values were -22, 21, 23, -6, -31 and 16 percent for the head, neck, chest, abdomen-pelvis, pelvis, spine CT exams, respectively. The average value of CTDIv calculated for each protocol was: 27.32 ± 0.9, 18.08 ± 2.0, 7.36 ± 2.6, 8.84 ± 1.7, 9.13 ± 1.5, 10.42 ± 0.8 mGy for the head, neck, chest, abdomen-pelvis and spine CT exams, respectively. Conclusions: The highest organ doses delivered by various CT exams were received by brain (15.5 mSv), thyroid (19.00 mSv), lungs (9.3 mSv) and bladder (9.9 mSv), bladder (10.4 mSv), stomach (10.9 mSv) in the head, neck, chest, and the abdomen-pelvis, pelvis, and spine respectively. Except the neck and spine CT exams showing a higher effective dose compared to that reported in Netherlands, other exams indicated lower values compared to those reported by any other country.

In-situ X-ray CT results of damage evolution in L6 ordinary chondrite meteorites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cuadra, Jefferson A.; Hazeli, Kavan; Ramesh, K. T.

2016-06-17

These are slides about in-situ X-ray CT results of damage evolution in L6 ordinary chondrite meteorites. The following topics are covered: mechanical and thermal damage characterization, list of Grosvenor Mountain (GRO) meteorite samples, in-situ x-ray compression test setup, GRO-chipped reference at 0 N - existing cracks, GRO-chipped loaded at 1580 N, in-situ x-ray thermal fatigue test setup, GRO-B14 room temperature reference, GRO-B14 Cycle 47 at 200°C, GRO-B14 Cycle 47 at room temperature, conclusions from qualitative analysis, future work and next steps. Conclusions are the following: Both GRO-Chipped and GRO-B14 had existing voids and cracks within the volume. These sites withmore » existing damage were selected for CT images from mechanically and thermally loaded scans since they are prone to damage initiation. The GRO-Chipped sample was loaded to 1580 N which resulted in a 14% compressive engineering strain, calculated using LVDT. Based on the CT cross sectional images, the GRO-B14 sample at 200°C has a thermal expansion of approximately 96 μm in height (i.e. ~1.6% engineering strain).« less

CMOS Active Pixel Sensors as energy-range detectors for proton Computed Tomography.

PubMed

Esposito, M; Anaxagoras, T; Evans, P M; Green, S; Manolopoulos, S; Nieto-Camero, J; Parker, D J; Poludniowski, G; Price, T; Waltham, C; Allinson, N M

2015-06-03

Since the first proof of concept in the early 70s, a number of technologies has been proposed to perform proton CT (pCT), as a means of mapping tissue stopping power for accurate treatment planning in proton therapy. Previous prototypes of energy-range detectors for pCT have been mainly based on the use of scintillator-based calorimeters, to measure proton residual energy after passing through the patient. However, such an approach is limited by the need for only a single proton passing through the energy-range detector in a read-out cycle. A novel approach to this problem could be the use of pixelated detectors, where the independent read-out of each pixel allows to measure simultaneously the residual energy of a number of protons in the same read-out cycle, facilitating a faster and more efficient pCT scan. This paper investigates the suitability of CMOS Active Pixel Sensors (APSs) to track individual protons as they go through a number of CMOS layers, forming an energy-range telescope. Measurements performed at the iThemba Laboratories will be presented and analysed in terms of correlation, to confirm capability of proton tracking for CMOS APSs.

Effect of ionizing radiation on the quantitative detection of Salmonella using real-time PCR

NASA Astrophysics Data System (ADS)

Lim, Sangyong; Jung, Jinwoo; Kim, Minjeong; Ryu, Sangryeol; Kim, Dongho

2008-09-01

Food irradiation is an economically viable technology for inactivating foodborne pathogens, but irradiation can mask pathogens in unhygienically prepared food. The aim of this study was to investigate the effect of irradiation treatment on the detection of Salmonella using real-time PCR. Three commercially available kits were tested, of which the InstaGene Matrix procedure was most effective in preparing template DNA from Salmonella exposed to radiation in broth culture. The minimum level of detection by real-time PCR combined with InstaGene Matrix was 3 log units of Salmonella per milliliter. However, when pure cultures of Salmonella were irradiated at 3 and 5 kGy, the cycle threshold ( CT) increased 1-1.5-fold compared to irradiation at 0 and 1 kGy. This indicated that irradiation treatment may result in an underestimation of bacterial counts due to radiation-induced DNA lesions. We also compared CT values in inoculated chicken homogenates before and after irradiation, which in this model caused a 1.3-3.3-fold underestimation of bacterial counts with respect to irradiation dose.

Incremental value of 99mTc-HYNIC-TOC SPECT/CT over whole-body planar scintigraphy and SPECT in patients with neuroendocrine tumours.

PubMed

Trogrlic, Mate; Težak, Stanko

2017-06-12

The aim of this study was to evaluate the additional value of 99m Tc-HYNIC-TOC SPECT/CT over planar whole-body (WB) scintigraphy and SPECT alone in the detection and accurate localisation of neuroendocrine tumour (NET) lesions. This study included 65 patients with a definitive histological diagnosis of NET prior to scintigraphy. Planar WB scintigraphy, SPECT, and SPECT/CT images were acquired at 4 h post-administration of 670 MBq 99m Tc-HYNIC-TOC. Additional SPECT images at 10 min after tracer administration were also acquired. Clinical and imaging follow-up findings were considered as the reference standards (minimum follow-up period, 15 months). Patient and lesion-based analyses of the efficacies of the imaging modalities were performed. While 38 patients exhibited metastasis of NETs, 27 presented no evidence of metastasis. Upon patient-based analysis, the sensitivity and specificity of SPECT/CT were found to be 88.9 and 79.3 %, respectively. The diagnostic accuracies of WB scintigraphy, 4h-SPECT, and SPECT/CT were 72.3, 73.8, and 84.6 %, respectively. The area under curve (AUC) value for SPECT/CT (0.84) was the highest, followed by those for 4h-SPECT (0.75) and WB scintigraphy (0.74). The accuracy and AUC values of SPECT/CT were significantly better compared to those of WB scintigraphy (p < 0.001), 10 min-SPECT (p < 0.001), and 4 h-SPECT (p = 0.001). The findings of SPECT/CT led to the change in treatment plan of 11 patients (16.9 %). The sensitivity and diagnostic accuracy of SPECT/CT in the evaluation of NET lesions outperforms planar WB imaging or SPECT alone.

The optimization of total laboratory automation by simulation of a pull-strategy.

PubMed

Yang, Taho; Wang, Teng-Kuan; Li, Vincent C; Su, Chia-Lo

2015-01-01

Laboratory results are essential for physicians to diagnose medical conditions. Because of the critical role of medical laboratories, an increasing number of hospitals use total laboratory automation (TLA) to improve laboratory performance. Although the benefits of TLA are well documented, systems occasionally become congested, particularly when hospitals face peak demand. This study optimizes TLA operations. Firstly, value stream mapping (VSM) is used to identify the non-value-added time. Subsequently, batch processing control and parallel scheduling rules are devised and a pull mechanism that comprises a constant work-in-process (CONWIP) is proposed. Simulation optimization is then used to optimize the design parameters and to ensure a small inventory and a shorter average cycle time (CT). For empirical illustration, this approach is applied to a real case. The proposed methodology significantly improves the efficiency of laboratory work and leads to a reduction in patient waiting times and increased service level.

Unenhanced Computed Tomography to Visualize Hollow Viscera and/or Mesenteric Injury After Blunt Abdominal Trauma: A Single-Institution Experience.

PubMed

Yang, Xu-Yang; Wei, Ming-Tian; Jin, Cheng-Wu; Wang, Meng; Wang, Zi-Qiang

2016-03-01

To identify and describe the major features of unenhanced computed tomography (CT) images of blunt hollow viscera and/or mesenteric injury (BHVI/MI) and to determine the value of unenhanced CT in the diagnosis of BHVI/MI. This retrospective study included 151 patients who underwent unenhanced CT before laparotomy for blunt abdominal trauma between January 2011 and December 2013. According to surgical observations, patients were classified as having BHVI/MI (n = 73) or not (n = 78). Sensitivity, specificity, P values, and likelihood ratios were calculated by comparing CT findings between the 2 groups. Six significant CT findings (P < 0.05) for BHVI/MI were identified and their sensitivity and specificity values determined, as follows: bowel wall thickening (39.7%, 96.2%), mesentery thickening (46.6%, 88.5%), mesenteric fat infiltration (12.3%, 98.7%), peritoneal fat infiltration (31.5%, 87.1%), parietal peritoneum thickening (30.1%, 85.9%), and intra- or retro-peritoneal air (34.2%, 96.2%). Unenhanced CT scan was useful as an initial assessment tool for BHVI/MI after blunt abdominal trauma. Six key features on CT were correlated with BHVI/MI.

Metastases to the Liver from Neuroendocrine Tumors: Effect of Duration of Scan Acquisition on CT Perfusion Values

PubMed Central

Hobbs, Brian P.; Chandler, Adam G.; Anderson, Ella F.; Herron, Delise H.; Charnsangavej, Chusilp; Yao, James

2013-01-01

Purpose To assess the effects of acquisition duration on computed tomographic (CT) perfusion parameter values in neuroendocrine liver metastases and normal liver tissue. Materials and Methods This retrospective study was institutional review board approved, with waiver of informed consent. CT perfusion studies in 16 patients (median age, 57.5 years; range, 42.0–69.7 years), including six men (median, 54.1 years; range, 42.0–69.7), and 10 women (median, 59.3 years; range 43.6–66.3), with neuroendocrine liver metastases were analyzed by means of distributed parametric modeling to determine tissue blood flow, blood volume, mean transit time, permeability, and hepatic arterial fraction for tumors and normal liver tissue. Analyses were undertaken with acquisition time of 12–590 seconds. Nonparameteric regression analyses were used to evaluate the functional relationships between CT perfusion parameters and acquisition duration. Evidence for time invariance was evaluated for each parameter at multiple time points by inferring the fitted derivative to assess its proximity to zero as a function of acquisition time by using equivalence tests with three levels of confidence (20%, 70%, and 90%). Results CT perfusion parameter values varied, approaching stable values with increasing acquisition duration. Acquisition duration greater than 160 seconds was required to obtain at least low confidence stability in any of the CT perfusion parameters. At 160 seconds of acquisition, all five CT perfusion parameters stabilized with low confidence in tumor and normal tissues, with the exception of hepatic arterial fraction in tumors. After 220 seconds of acquisition, there was stabilization with moderate confidence for blood flow, blood volume, and hepatic arterial fraction in tumors and normal tissue, and for mean transit time in tumors; however, permeability values did not satisfy the moderate stabilization criteria in both tumors and normal tissue until 360 seconds of acquisition. Blood flow, mean transit time, permeability, and hepatic arterial fraction were significantly different between tumor and normal tissue at 360 seconds (P < .001). Conclusion CT perfusion parameter values are affected by acquisition duration and approach progressively stable values with increasing acquisition times. © RSNA, 2013 Online supplemental material is available for this article. PMID:23824990

Consistent Evaluation of ACOS-GOSAT, BESD-SCIAMACHY, CarbonTracker, and MACC Through Comparisons to TCCON

NASA Technical Reports Server (NTRS)

Kulawik, Susan; Wunch, Debra; O’Dell, Christopher; Frankenberg, Christian; Reuter, Maximilian; Chevallier, Frederic; Oda, Tomohiro; Sherlock, Vanessa; Buchwitz, Michael; Osterman, Greg;

Comparing SUV values of images at PET-CT console and the RT planning console using identical dataset of a study phantom.

PubMed

Munshi, Anusheel; Paul, Sayan; Sarkar, Biplab; Bala, Pinkey; Ganesh, Tharmar; Sen, Ishita B; Pant, Vineet; Mohanti, Bidhu K

2016-01-01

The use of positron emission tomography (PET) for radiotherapy planning purposes has become increasingly important in the last few years.In the current study, we compared the SUV values of images at the PET CT console to the SUV values obtained at the RT planning workstation. The PET-CT cylindrical body phantom was filled with a uniform 18F solution of 5.3. ± 0.27 kBq/mL radioactivity concentration. PET-CT scans were performed on a16 slice Time of Flight system. On a single day, the three consecutive scans were done at three time points 15 minutes apart to generate time points image data sets titled T1, T2, and T3. SUV calculations were performed by drawing region of interest. (ROI) encompassing the entire hot spot on each slice on the PET-CT console and the iPlan workstation. Minimum SUV, Maximum SUV and the Mean SUV were recorded. Statistical analysis was done using the SPSS software. (SPSS Inc.) (Version 18). The absolute difference in average max SUV values i.e. Max (PET-CT) - Max (iPlan) for the time points T1, T2 and T3 were -0.168 (SD 0.175), -0.172 (SD 0.172) and -0.178 (SD 0.169). The difference in the minimum SUV values were -0.513 (SD 0.428), -0.311 (SD 0.358) and -0.303 (SD 0.322), respectively. Finally, the difference in the mean SUV values were -0.107 (SD 0.040), -0.096 (SD 0.067) and -0.072 (SD 0.044), respectively. Our study found out that the average difference in the two systems for maximum SUV values was < 0.2 absolute units.Our study suggests good reproducibility of SUV between the two systems. The relevance of these findings would be of seminal importance in current and future SUV-based PET-CT-based contouring in treatment planning systems.

Efficacy of CT in diagnosis of transudates and exudates in patients with pleural effusion

PubMed Central

Çullu, Neşat; Kalemci, Serdar; Karakaş, Ömer; Eser, İrfan; Yalçın, Funda; Boyacı, Fatıma Nurefşan; Karakaş, Ekrem

2014-01-01

PURPOSE We aimed to evaluate the efficacy of multidetector computed tomography (CT) imaging in diagnosis of pleural exudates and transudates using attenuation values. MATERIALS AND METHODS This retrospective study included 106 patients who were diagnosed with pleural effusion between January 2010 and June 2012. After the patients underwent chest CT, thoracentesis was performed in the first week. The attenuation values of the pleural effusions were measured in all patients. RESULTS According to Light’s criteria, 30 of 106 patients with pleural effusions had transudates, and the remaining patients had exudates. The Hounsfield unit (HU) value of the exudates (median, 12.5; range, 4–33) was significantly higher than that of the transudates (median, 5; range, 2–15) (P = 0.001). Additionally, when evaluated by disease subgroups, congestive heart failure and empyema were predictable in terms of median HU values of the pleural effusions with high and moderate sensitivity and specificity values (84.6% and 81.2%, respectively; 76.9% and 66.7%, respectively). Compared with other patients, the empyema patients had significantly more loculation and pleural thickening. CONCLUSION CT attenuation values may be useful in differentiating exu-dates from transudates. Although there is an overlap in most effusions, exudate can be considered when the CT attenuation values are >15 HU. Because of overlapping HU values, close correlation with clinical findings is essential. Additional signs, such as fluid loculation and pleural thickness, should be considered and may provide further information for the differentiation. PMID:24100060

Efficacy of CT in diagnosis of transudates and exudates in patients with pleural effusion.

PubMed

Çullu, Neşat; Kalemci, Serdar; Karakaş, Ömer; Eser, İrfan; Yalçin, Funda; Boyacı, Fatıma Nurefşan; Karakaş, Ekrem

2014-01-01

We aimed to evaluate the efficacy of multidetector computed tomography (CT) imaging in diagnosis of pleural exudates and transudates using attenuation values. This retrospective study included 106 patients who were diagnosed with pleural effusion between January 2010 and June 2012. After the patients underwent chest CT, thoracentesis was performed in the first week. The attenuation values of the pleural effusions were measured in all patients. According to Light's criteria, 30 of 106 patients with pleural effusions had transudates, and the remaining patients had exudates. The Hounsfield unit (HU) value of the exudates (median, 12.5; range, 4-33) was significantly higher than that of the transudates (median, 5; range, 2-15) (P = 0.001). Additionally, when evaluated by disease subgroups, congestive heart failure and empyema were predictable in terms of median HU values of the pleural effusions with high and moderate sensitivity and specificity values (84.6% and 81.2%, respectively; 76.9% and 66.7%, respectively). Compared with other patients, the empyema patients had significantly more loculation and pleural thickening. CT attenuation values may be useful in differentiating exudates from transudates. Although there is an overlap in most effusions, exudate can be considered when the CT attenuation values are >15 HU. Because of overlapping HU values, close correlation with clinical findings is essential. Additional signs, such as fluid loculation and pleural thickness, should be considered and may provide further information for the differentiation.

[Mountain biking : Breezy ups and traumatic downs].

PubMed

Schueller, G

2010-05-01

For more than two decades the popularity of mountain biking as a national pastime as well as a competitive sport has been undiminished. However, its related risks are not monitored as closely as those, for example, of skiing. The injuries caused by mountain biking are specific and cannot be compared with those caused by other cycling sports. This is due not only to the characteristics of the terrain but also to the readiness to assume a higher risk compared to cycle racing.The particular value of radiology is in the acute trauma setting. Most often musculoskeletal lesions must be examined and digital radiography and MRI are the most useful techniques. Severe trauma of the cranium, face, spine, thorax and abdomen are primarily evaluated with CT, particularly in dedicated trauma centers. Therefore, radiology can play a role in the rapid diagnosis and optimal treatment of the trauma-related injuries of mountain biking. Thus, the unnecessarily high economical damage associated with mountain biking can be avoided.

Volumetric Single-Beat Coronary Computed Tomography Angiography: Relationship of Image Quality, Heart Rate, and Body Mass Index. Initial Patient Experience With a New Computed Tomography Scanner.

PubMed

Latif, Muhammad Aamir; Sanchez, Frank W; Sayegh, Karl; Veledar, Emir; Aziz, Muhammad; Malik, Rehan; Haider, Imran; Agatston, Arthur S; Batlle, Juan C; Janowitz, Warren; Peña, Constantino; Ziffer, Jack A; Nasir, Khurram; Cury, Ricardo C

2016-01-01

Cardiac computed tomography (CT) image quality (IQ) is very important for accurate diagnosis. We propose to evaluate IQ expressed as Likert scale, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) from coronary CT angiography images acquired with a new volumetric single-beat CT scanner on consecutive patients and assess the IQ dependence on heart rate (HR) and body mass index (BMI). We retrospectively analyzed the data of the first 439 consecutive patients (mean age, 55.13 [SD, 12.1] years; 51.47% male), who underwent noninvasive coronary CT angiography in a new single-beat volumetric CT scanner (Revolution CT) to evaluate chest pain at West Kendall Baptist Hospital. Based on patient BMI (mean, 29.43 [SD, 5.81] kg/m), the kVp (kilovolt potential) value and tube current were adjusted within a range of 80 to 140 kVp and 122 to 720 mA, respectively. Each scan was performed in a single-beat acquisition within 1 cardiac cycle, regardless of the HR. Motion correction software (SnapShot Freeze) was used for correcting motion artifacts in patients with higher HRs. Autogating was used to automatically acquire systolic and diastolic phases for higher HRs with electrocardiographic milliampere dose modulation. Image quality was assessed qualitatively by Likert scale and quantitatively by SNR and CNR for the 4 major vessels right coronary, left main, left anterior descending, and left circumflex arteries on axial and multiplanar reformatted images. Values for Likert scale were as follows: 1, nondiagnostic; 2, poor; 3, good; 4, very good; and 5, excellent. Signal-to-noise ratio and CNR were calculated from the average 2 CT attenuation values within regions of interest placed in the proximal left main and proximal right coronary artery. For contrast comparison, a region of interest was selected from left ventricular wall at midcavity level using a dedicated workstation. We divided patients in 2 groups related to the HR: less than or equal to 70 beats/min (bpm) and greater than 70 bpm and also analyzed them in 2 BMI groupings: BMI less than or equal to 30 kg/m and BMI greater than 30 kg/m. Mean SNR was 8.7 (SD, 3.1) (n = 349) for group with HR 70 bpm or less and 7.7 (SD, 2.4) (n = 78) for group with HR greater than 70 bpm (P = 0.008). Mean CNR was 6.9 (SD, 2.7) (n = 349) for group with HR 70 bpm or less and 5.9 (SD, 2.2) (n = 78) for group with HR 70 bpm or greater (P = 0.002). Mean SNR was 8.8 (SD, 3.2) (n = 249) for group with BMI 30 kg/m or less and 8.1 (SD, 2.6) (n = 176) for group with BMI greater than 30 kg/m (P = 0.008). Mean CNR was 7.0 (SD, 2.8) (n = 249) for group with BMI 30 kg/m or less and 6.4 (SD, 2.4) (n = 176) for group with BMI greater than 30 kg/m (P = 0.002). The results for mean Likert scale values were statistically different, reflecting difference in IQ between people with HR 70 bpm or less and greater than 70 bpm, BMI 30 kg/m or less, and BMI greater than 30 kg/m.

In Vivo Evaluation of Chemical Composition of Eight Types of Urinary Calculi Using Spiral Computerized Tomography in a Chinese Population.

PubMed

Huo, Jun; Liu, Zhong-Yuan; Wang, Ke-Feng; Xu, Zhen-Qun

2015-09-01

This study was conducted to evaluate the chemical composition of eight types of urinary calculi using spiral computerized tomography (CT) in vivo. From October 2011 to February 2013, upper urinary tract calculi were obtained from 122 patients in the department of urinary surgery of the First Affiliated Hospital of Soochow University. All patients were scanned with a 64-detector row helical CT scanner using 6.50 mm collimation before ureterorenoscopy. Data from the preoperative spiral CT scans and postoperative chemical composition of urinary calculi were collected. The chemical composition analysis indicates that there were five types of pure calculi and three types of mixed calculi, including 39 calcium oxalate calculi, 12 calcium phosphate calculi, 10 calcium carbonate calculi, 8 magnesium ammonium phosphate calculi, 6 carbonated apatite, 21 uric acid/ammonium urate calculi, 10 uric acid/calcium oxalate calculi, and 16 calcium oxalate/calcium phosphate calculi. There were significant differences in the mean CT values among the five types of pure calculi (P < 0.001). Furthermore, we also observed significant differences in the mean CT values among three types of mixed calculi (P < 0.001). Significant differences in the mean CT values were also found among eight types of urinary calculi (P < 0.001). However, no statistically significant difference was observed between the mean CT values of magnesium ammonium phosphate calculi and uric acid/calcium oxalate calculi (P = 0.262). Our findings suggest that spiral CT could be a promising tool for determining the chemical composition of upper urinary tract calculi. © 2014 Wiley Periodicals, Inc.

Dosimetric Quantities for Computed Tomography Examinations of Paediatric Patients on the Thoracic and Abdominal Regions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flores-M, E.; Gamboa de Buen, I.; Buenfil, A. E.

Computed Tomography (CT) is a high dose X ray imaging procedure and its use has rapidly increased in the last two decades fueled by the development of helical CT. The aim of this study is to present values of the dosimetric quantities for CT paediatric examinations of thoracic and abdominal regions. The protocols studied were those of chest, lung-mediastine, chest-abdomen, pulmonary high resolution and mediastine-abdomen, which are the more common examinations performed at ''Hospital Infantil de Mexico Federico Gomez'' in the thoracic-abdominal region. The measurements were performed on a Siemens SOMATOM Sensation 16 CT Scanner and the equipment used wasmore » a CT pencil ionization chamber, connected to an electrometer. This system was calibrated for RQT9 CT beam quality. A PMMA head phantom with diameter of 16 cm and length of 15 cm was also used. The dosimetric quantities measured were the weighted air kerma index (C{sub w}), the volumetric dose index (C{sub vol}) and the CT air kerma-length product. It was found that the pulmonary high resolution examination presented the highest values for the C{sub w}(31.1 mGy) and C{sub vol}(11.1 mGy). The examination with the lowest values of these two quantities was the chest-abdomen protocol with 10.5 mGy for C{sub w} and 5.5 mGy for C{sub vol}. However, this protocol presented the highest value for P{sub KL,CT}(282.2 mGy cm) when considering the average clinical length of the examinations.« less

The impact of manual threshold selection in medical additive manufacturing.

PubMed

van Eijnatten, Maureen; Koivisto, Juha; Karhu, Kalle; Forouzanfar, Tymour; Wolff, Jan

2017-04-01

Medical additive manufacturing requires standard tessellation language (STL) models. Such models are commonly derived from computed tomography (CT) images using thresholding. Threshold selection can be performed manually or automatically. The aim of this study was to assess the impact of manual and default threshold selection on the reliability and accuracy of skull STL models using different CT technologies. One female and one male human cadaver head were imaged using multi-detector row CT, dual-energy CT, and two cone-beam CT scanners. Four medical engineers manually thresholded the bony structures on all CT images. The lowest and highest selected mean threshold values and the default threshold value were used to generate skull STL models. Geometric variations between all manually thresholded STL models were calculated. Furthermore, in order to calculate the accuracy of the manually and default thresholded STL models, all STL models were superimposed on an optical scan of the dry female and male skulls ("gold standard"). The intra- and inter-observer variability of the manual threshold selection was good (intra-class correlation coefficients >0.9). All engineers selected grey values closer to soft tissue to compensate for bone voids. Geometric variations between the manually thresholded STL models were 0.13 mm (multi-detector row CT), 0.59 mm (dual-energy CT), and 0.55 mm (cone-beam CT). All STL models demonstrated inaccuracies ranging from -0.8 to +1.1 mm (multi-detector row CT), -0.7 to +2.0 mm (dual-energy CT), and -2.3 to +4.8 mm (cone-beam CT). This study demonstrates that manual threshold selection results in better STL models than default thresholding. The use of dual-energy CT and cone-beam CT technology in its present form does not deliver reliable or accurate STL models for medical additive manufacturing. New approaches are required that are based on pattern recognition and machine learning algorithms.

Measurement of time delay for a prospectively gated CT simulator.

PubMed

Goharian, M; Khan, R F H

2010-04-01

For the management of mobile tumors, respiratory gating is the ideal option, both during imaging and during therapy. The major advantage of respiratory gating during imaging is that it is possible to create a single artifact-free CT data-set during a selected phase of the patient's breathing cycle. The purpose of the present work is to present a simple technique to measure the time delay during acquisition of a prospectively gated CT. The time delay of a Philips Brilliance BigBore (Philips Medical Systems, Madison, WI) scanner attached to a Varian Real-Time Position Management (RPM) system (Varian Medical Systems, Palo Alto, CA) was measured. Two methods were used to measure the CT time delay: using a motion phantom and using a recorded data file from the RPM system. In the first technique, a rotating wheel phantom was altered by placing two plastic balls on its axis and rim, respectively. For a desired gate, the relative positions of the balls were measured from the acquired CT data and converted into corresponding phases. Phase difference was calculated between the measured phases and the desired phases. Using period of motion, the phase difference was converted into time delay. The Varian RPM system provides an external breathing signal; it also records transistor-transistor logic (TTL) 'X-Ray ON' status signal from the CT scanner in a text file. The TTL 'X-Ray ON' indicates the start of CT image acquisition. Thus, knowledge of the start time of CT acquisition, combined with the real-time phase and amplitude data from the external respiratory signal, provides time-stamping of all images in an axial CT scan. The TTL signal with time-stamp was used to calculate when (during the breathing cycle) a slice was recorded. Using the two approaches, the time delay between the prospective gating signal and CT simulator has been determined to be 367 +/- 40 ms. The delay requires corrections both at image acquisition and while setting gates for the treatment delivery; otherwise the simulation and treatment may not be correlated with the patient's breathing.

Predictive value of abdominal CT in evaluating internal herniation after bariatric laparoscopic Roux-en-Y gastric bypass.

PubMed

Ederveen, J C; van Berckel, M M G; Nienhuijs, S W; Weber, R J P; Nederend, J

2018-06-04

Internal herniation, a serious complication after bariatric surgery, is challenging to diagnose. The aim of this study was to determine the accuracy of abdominal CT in diagnosing internal herniation. The study included consecutive patients who had undergone laparoscopic gastric bypass surgery between 1 January 2011 and 1 January 2015 at a bariatric centre of excellence. To select patients suspected of having internal herniation, reports of abdominal CT and reoperations up to 1 January 2017 were screened. CT was presumed negative for internal herniation if no follow-up CT or reoperation was performed within 90 days after the initial CT, or no internal herniation was found during reoperation. The accuracy of abdominal CT in diagnosing internal herniation was calculated using two-way contingency tables. A total of 1475 patients were included (84·7 per cent women, mean age 46·5 years, median initial BMI 41·8 kg/m 2 ). CT and/or reoperation was performed in 192 patients (13·0 per cent) in whom internal herniation was suspected. Internal herniation was proven laparoscopically in 37 of these patients. The incidence of internal herniation was 2·5 per cent. An analysis by complaint included a total of 265 episodes, for which 247 CT scans were undertaken. CT was not used to investigate 18 episodes, but internal herniation was encountered in one-third of these during reoperation. Combining the follow-up and intraoperative findings, the accuracy of CT for internal herniation had a sensitivity of 83·8 (95 per cent c.i. 67·3 to 93·2) per cent, a specificity of 87·1 (81·7 to 91·2) per cent, a positive predictive value of 53·4 (40·0 to 66·5) per cent and a negative predictive value of 96·8 (92·9 to 98·7) per cent. Abdominal CT is an important tool in diagnosing internal herniation, with a high specificity and a high negative predictive value. © 2018 BJS Society Ltd Published by John Wiley & Sons Ltd.

Effects of bacterial contamination of media on the diagnosis of Tritrichomonas foetus by culture and real-time PCR.

PubMed

Clothier, Kristin A; Villanueva, Michelle; Torain, Andrea; Hult, Cynthia; Wallace, Rachel

2015-03-15

The venereal pathogen Tritrichomonas foetus causes early embryonic death and abortion in cattle. With no approved treatment, control involves detection of infected animals and their removal from the herd. Culture is the traditional diagnostic method; standard media are formulated to support protozoal growth while suppressing competing organisms which may prevent microscopic recognition of T. foetus. Real-time PCR increases diagnostic sensitivity and specificity over culture but requires intact T. foetus DNA for detection. The purposes of this study were 1) to evaluate the effects of resident preputial bacteria that are not suppressed by antimicrobials in a commercial culture medium (InPouch™) on T. foetus detection by culture and PCR, and 2) to determine the performance of a laboratory-prepared culture medium on T. foetus detection by culture and PCR in samples with and without this bacterial contamination. A known concentration of one of three different strains of T. foetus inoculated into InPouch™ (IP) or modified Diamonds-Plastridge media (DPM) were co-incubated with a smegma culture media (CONTAM) for 24h and examined microscopically for the presence of identifiable T. foetus. PCR was performed on IP samples to determine if CONTAM also affected T. foetus DNA detection. A PCR protocol was then validated in DPM that performed similarly to the established IP PCR method. IP and DPM with CONTAM were spiked with serial dilutions that mimic field infections of one of four T. foetus strains and evaluated by real-time PCR; cycles to threshold (Ct) values and "positive" classification were compared between media. T. foetus motility and morphology as well as media pH were severely altered in IP samples with CONTAM compared to those without as well as to DPM medium with and without CONTAM (P<0.0001). PCR testing demonstrated significantly greater Ct values were for T. foetus DNA (P<0.001) in IP contaminated with smegma bacteria compared to those without. When using T foetus concentrations that mimic field infections, IP samples with CONTAM had significantly higher Ct values (P<0.001) than DPM with CONTAM. Using the laboratory cut-off for "positive" on mean Ct values from these samples, significantly (P<0.01) more bulls would be identified using DPM than with IP if CONTAM was present. Results of this study indicate that bacteria which are not inhibited in media interfere with T. foetus identification by culture and PCR and adversely affect diagnostic sensitivity for this fastidious pathogen. Copyright © 2015 Elsevier B.V. All rights reserved.

Can Chest Computed Tomography Be Replaced by Lung Ultrasonography With or Without Plain Chest Radiography in Pediatric Pneumonia?

PubMed

Hajalioghli, Parisa; Nemati, Masoud; Dinparast Saleh, Leila; Fouladi, Daniel F

2016-07-01

The purpose of this study was to answer the following question: can chest computed tomography (CT) requested by pediatricians be replaced by lung ultrasonography (US) with or without chest radiography in pediatric pneumonia? A total of 98 children with suspected pneumonia who were referred by pediatricians for CT examinations were prospectively studied. Levels of agreement between CT findings and plain radiography, lung US, and chest radiography plus lung US results were investigated. CT defined pneumonia in 84 patients, among which 26 cases were complicated. κ values between radiography and CT findings were 0.82 in complicated cases, 0.67 in uncomplicated cases, and 0.72 overall. The corresponding values between US and CT findings were 1, 0.52, and 0.62, respectively, and between radiography plus US and CT findings were 1, 0.86, and 0.88, respectively. CT can be replaced by US when complex effusions are present in children with pneumonia. In case of an ambiguous diagnosis of pediatric pneumonia with or without complex effusions, a combination of chest radiography and US is a reliable surrogate for chest CT.

Histopathologic diversity of gastric cancers: Relationship between enhancement pattern on dynamic contrast-enhanced CT and histological type.

PubMed

Tsurumaru, Daisuke; Miyasaka, Mitsutoshi; Muraki, Toshio; Nishie, Akihiro; Asayama, Yoshiki; Oki, Eiji; Oda, Yoshinao; Honda, Hiroshi

2017-12-01

To evaluate the diagnostic value of contrast-enhanced computed tomography gastrography (CE-CTG) to predict the histological type of gastric cancer. We analyzed 47 consecutive patients with resectable advanced gastric cancer preoperatively evaluated by multiphasic dynamic contrast-enhanced CT. Two radiologists independently reviewed the CT images and they determined the peak enhancement phase, and then measured the CT attenuation value of the gastric lesion for each phase. The histological types of gastric cancers were assigned to three groups as differentiated-type, undifferentiated-type, and mixed-type. We compared the peak enhancement phase of the three types and compared the CT attenuation values in each phase. The peak enhancement was significantly different between the three types of gastric cancers for both readers (reader 1, p=0.001; reader 2, p=0.009); most of the undifferentiated types had peak enhancement in the delayed phase. The CT attenuation values of undifferentiated type were significantly higher than those of differentiated or mixed type in the delayed phase according to both readers (reader 1, p=0.002; reader 2, p=0.004). CE-CTG could provide helpful information in diagnosing the histological type of gastric cancers preoperatively. Copyright © 2017 Elsevier B.V. All rights reserved.

320-row CT renal perfusion imaging in patients with aortic dissection: A preliminary study.

PubMed

Liu, Dongting; Liu, Jiayi; Wen, Zhaoying; Li, Yu; Sun, Zhonghua; Xu, Qin; Fan, Zhanming

2017-01-01

To investigate the clinical value of renal perfusion imaging in patients with aortic dissection (AD) using 320-row computed tomography (CT), and to determine the relationship between renal CT perfusion imaging and various factors of aortic dissection. Forty-three patients with AD who underwent 320-row CT renal perfusion before operation were prospectively enrolled in this study. Diagnosis of AD was confirmed by transthoracic echocardiography. Blood flow (BF) of bilateral renal perfusion was measured and analyzed. CT perfusion imaging signs of AD in relation to the type of AD, number of entry tears and the false lumen thrombus were observed and compared. The BF values of patients with type A AD were significantly lower than those of patients with type B AD (P = 0.004). No significant difference was found in the BF between different numbers of intimal tears (P = 0.288), but BF values were significantly higher in cases with a false lumen without thrombus and renal arteries arising from the true lumen than in those with thrombus (P = 0.036). The BF values measured between the true lumen, false lumen and overriding groups were different (P = 0.02), with the true lumen group having the highest. Also, the difference in BF values between true lumen and false lumen groups was statistically significant (P = 0.016), while no statistical significance was found in the other two groups (P > 0.05). The larger the size of intimal entry tears, the greater the BF values (P = 0.044). This study shows a direct correlation between renal CT perfusion changes and AD, with the size, number of intimal tears, different types of AD, different renal artery origins and false lumen thrombosis, significantly affecting the perfusion values.

Modification of atrioventricular nodal electrophysiology by selective radiofrequency delivery on the anterior or posterior approaches.

PubMed

Chorro, F J; Sanchis, J; Such, L; Artal, L; Llavador, J J; Llavador, E; Monmeneu, J V; López-Merino, V

1997-05-01

An analysis was made in 14 isolated and perfused rabbit hearts of the electrophysiological effects of selective radiofrequency (RF) delivery in the anterior (group I, n = 7) or posterior zone (group II, n = 7) of the Koch triangle, with the aim of modifying atrioventricular nodal (AVN) conduction without suppressing 1:1 transmission. After opening the right atrium, RF was delivered (0.5 W) with a 1-mm diameter unipolar electrode positioned in the selected zone until a prolongation of no less than 15% was obtained in the Wenckebach cycle length (WCL). Before and after (30 min) RF, anterograde and retrograde AVN refractoriness and conduction were evaluated, stimulating from the crista terminalis (CT), the interatrial septum (IAS), and from the RV epicardium. After RF, the following percentage increments were observed in group I: AH(CT) = 36% +/- 9%, AH(IAS) = 38% +/- 11%, WCL(CT) = 28% +/- 8%, WCL(IAS) = 22% +/- 6%, functional refractory period (FRP) of the AVN(CT) = 13% +/- 11%, FRP-AVN(IAS) = 13% +/- 8%, retrograde WCL = 20% +/- 19%, and retrograde FRPVA = 13% +/- 16%. The increments observed in group II and the significances of the differences with respect to group I were: AH(CT) = 11% +/- 14% (P < 0.01), AH(IAS) = 19% +/- 32% (NS), WCL(CT) = 42% +/- 14% (P < 0.05), WCL(IAS) = 42% +/- 16% (P < 0.01), FRP-AVN(CT) = 28% +/- 28% (NS), FRP-AVN(LAS) = 21% +/- 19% (NS), retrograde WCL = 35% +/- 24% (NS), and retrograde FRP = 16% +/- 13% (NS). In both groups, the AH interval variations were not correlated with those of the rest of the parameters analyzed. Truncated nodal function curves suggestive of a dual AV nodal pathway were obtained in three experiments, though in only one of them was this observed under basal conditions. In the other two experiments, with dual AV nodal physiology only after RF (one from each group), AV nodal reentrant tachycardias were triggered with atrial extrastimulus at coupling intervals equal to or shorter than at those that cause a sudden lengthening of the AH interval, RF delivered in the anterior and posterior zones of the Koch triangle produced effects of different magnitude on the AH interval and Wenckebach cycle length. In the anterior zone the AH interval was prolonged to a greater extent, while in the posterior zone the effects were greater on the Wenckebach cycle length. No correlation existed between the variations in AH interval and Wenckebach cycle length, regardless of where RF was delivered. The evaluation of anterograde AV nodal refractoriness was similar when stimulating from the crista terminalis or from the interatrial septum. By delivering RF, it was possible to induce dual AV nodal physiology and reentrant tachycardias.

C-tactile afferent stimulating touch carries a positive affective value.

PubMed

Pawling, Ralph; Cannon, Peter R; McGlone, Francis P; Walker, Susannah C

2017-01-01

The rewarding sensation of touch in affiliative interactions is hypothesized to be underpinned by a specialized system of nerve fibers called C-Tactile afferents (CTs), which respond optimally to slowly moving, gentle touch, typical of a caress. However, empirical evidence to support the theory that CTs encode socially relevant, rewarding tactile information in humans is currently limited. While in healthy participants, touch applied at CT optimal velocities (1-10cm/sec) is reliably rated as subjectively pleasant, neuronopathy patients lacking large myelinated afferents, but with intact C-fibres, report that the conscious sensation elicited by stimulation of CTs is rather vague. Given this weak perceptual impact the value of self-report measures for assessing the specific affective value of CT activating touch appears limited. Therefore, we combined subjective ratings of touch pleasantness with implicit measures of affective state (facial electromyography) and autonomic arousal (heart rate) to determine whether CT activation carries a positive affective value. We recorded the activity of two key emotion-relevant facial muscle sites (zygomaticus major-smile muscle, positive affect & corrugator supercilii-frown muscle, negative affect) while participants evaluated the pleasantness of experimenter administered stroking touch, delivered using a soft brush, at two velocities (CT optimal 3cm/sec & CT non-optimal 30cm/sec), on two skin sites (CT innervated forearm & non-CT innervated palm). On both sites, 3cm/sec stroking touch was rated as more pleasant and produced greater heart rate deceleration than 30cm/sec stimulation. However, neither self-report ratings nor heart rate responses discriminated stimulation on the CT innervated arm from stroking of the non-CT innervated palm. In contrast, significantly greater activation of the zygomaticus major (smiling muscle) was seen specifically to CT optimal, 3cm/sec, stroking on the forearm in comparison to all other stimuli. These results offer the first empirical evidence in humans that tactile stimulation that optimally activates CTs carries a positive affective valence that can be measured implicitly.

Assessing the role of 18F-FDG PET and 18F-FDG PET/CT in the diagnosis of soft tissue musculoskeletal malignancies – A systematic review and meta-analysis

PubMed Central

Etchebehere, Elba C.; Hobbs, Brian P.; R.Milton, Denái; Malawi, Osama; Patel, Shreyaskumar; Benjamin, Robert S.; Macapinlac, Homer A.

2016-01-01

Purpose Twelve years ago a meta-analysis evaluated the diagnostic performance of 18F-FDG PET in assessing musculoskeletal soft tissue lesions (MsSTL). Currently, PET/CT has substituted PET imaging however there has not been any published meta-analysis on the use of PET/CT or a comparison of PET/CT with PET in the diagnosis of MsSTL. Therefore, we conducted a meta-analysis to identify the current diagnostic performance of 18F-FDG PET/CT and determine if there is added value when compared to PET. Patients and Methods A systematic review of English articles using MEDLINE PubMed, the Cochrane Library and EMBASE were searched from 1996 to March 2015. Studies exploring the diagnostic accuracy of 18F-FDG PET/CT (or dedicated PET) compared to histopathology in patients with MsSTL undergoing investigation for malignancy were included. Results Our meta-analysis included 14 articles composed of 755 patients with 757 soft tissue lesions. There were 451 (60%) malignant tumors and 306 benign lesions. The 18F-FDG PET/CT (and dedicated PET) mean sensitivity, specificity, accuracy, positive and negative predictive values for diagnosing MsSTL was 0.96 (0.90, 1.00), 0.77 (0.67, 0.86), 0.88 (0.85, 0.91), 0.86 (0.78, 0.94) and 0.91 (0.83, 0.99), respectively. The posterior mean (95% HPD interval) for the AUC was 0.92 (0.88, 0.96). PET/CT had higher specificity, accuracy and positive predictive value when compared to a dedicated PET (0.85, 0.89 and 0.91 vs 0.71, 0.85 and 0.82, respectively). Conclusions 18F-FDG PET/CT and dedicated PET are both highly accurate in the diagnosis of MsSTL. PET/CT is more accurate, specific and has a higher positive predictive value than PET. PMID:26631240

Synthesis and characterization of 2D molybdenum carbide (MXene)

DOE PAGES

Halim, Joseph; Kota, Sankalp; Lukatskaya, Maria R.; ...

2016-02-17

Large scale synthesis and delamination of 2D Mo 2CT x (where T is a surface termination group) has been achieved by selectively etching gallium from the recently discovered nanolaminated, ternary transition metal carbide Mo 2Ga 2C. Different synthesis and delamination routes result in different flake morphologies. The resistivity of free-standing Mo 2CT x films increases by an order of magnitude as the temperature is reduced from 300 to 10 K, suggesting semiconductor-like behavior of this MXene, in contrast to Ti 3C 2T x which exhibits metallic behavior. At 10 K, the magnetoresistance is positive. Additionally, changes in electronic transport aremore » observed upon annealing of the films. When 2 μm thick films are tested as electrodes in supercapacitors, capacitances as high as 700 F cm –3 in a 1 m sulfuric acid electrolyte and high capacity retention for at least 10,000 cycles at 10 A g –1 are obtained. Free-standing Mo 2CT x films, with ≈8 wt% carbon nanotubes, perform well when tested as an electrode material for Li-ions, especially at high rates. In conclusion, at 20 and 131 C cycling rates, stable reversible capacities of 250 and 76 mAh g –1, respectively, are achieved for over 1000 cycles.« less

A computed tomography-based spatial normalization for the analysis of [18F] fluorodeoxyglucose positron emission tomography of the brain.

PubMed

Cho, Hanna; Kim, Jin Su; Choi, Jae Yong; Ryu, Young Hoon; Lyoo, Chul Hyoung

2014-01-01

We developed a new computed tomography (CT)-based spatial normalization method and CT template to demonstrate its usefulness in spatial normalization of positron emission tomography (PET) images with [(18)F] fluorodeoxyglucose (FDG) PET studies in healthy controls. Seventy healthy controls underwent brain CT scan (120 KeV, 180 mAs, and 3 mm of thickness) and [(18)F] FDG PET scans using a PET/CT scanner. T1-weighted magnetic resonance (MR) images were acquired for all subjects. By averaging skull-stripped and spatially-normalized MR and CT images, we created skull-stripped MR and CT templates for spatial normalization. The skull-stripped MR and CT images were spatially normalized to each structural template. PET images were spatially normalized by applying spatial transformation parameters to normalize skull-stripped MR and CT images. A conventional perfusion PET template was used for PET-based spatial normalization. Regional standardized uptake values (SUV) measured by overlaying the template volume of interest (VOI) were compared to those measured with FreeSurfer-generated VOI (FSVOI). All three spatial normalization methods underestimated regional SUV values by 0.3-20% compared to those measured with FSVOI. The CT-based method showed slightly greater underestimation bias. Regional SUV values derived from all three spatial normalization methods were correlated significantly (p < 0.0001) with those measured with FSVOI. CT-based spatial normalization may be an alternative method for structure-based spatial normalization of [(18)F] FDG PET when MR imaging is unavailable. Therefore, it is useful for PET/CT studies with various radiotracers whose uptake is expected to be limited to specific brain regions or highly variable within study population.

The role of routine preoperative EUS when performed after contrast enhanced CT in the diagnostic work-up in patients suspected of pancreatic or periampullary cancer.

PubMed

Cieslak, Kasia P; van Santvoort, Hjalmar C; Vleggaar, Frank P; van Leeuwen, Maarten S; ten Kate, Fibo J; Besselink, Marc G; Molenaar, I Quintus

2014-01-01

In patients suspected of pancreatic or periampullary cancer, abdominal contrast-enhanced computed tomography (CT) is the standard diagnostic modality. A supplementary endoscopic ultrasonography (EUS) is often performed, although there is only limited evidence of its additional diagnostic value. The aim of the study is to evaluate the additional diagnostic value of EUS over CT in deciding on exploratory laparotomy in patients suspected of pancreatic or periampullary cancer. We retrospectively analyzed 86 consecutive patients who routinely underwent CT and EUS before exploratory laparotomy with or without pancreatoduodenectomy for suspected pancreatic or periampullary carcinoma between 2007 and 2010. Primary outcomes were visibility of a mass, resectability on CT/EUS and resection with curative intent. A mass was visible on CT in 72/86 (84%) patients. In these 72 patients, EUS demonstrated a mass in 64/72 (89%) patients. Resectability was accurately predicted by CT in 65/72 (90%) and by EUS in 58/72 (81%) patients. In 14/86 (16%) patients no mass was seen on CT. EUS showed a mass in 12/14 (86%) of these patients. A malignant lesion was histological proven in 11/12 (92%) of these patients. Overall, resectability was accurately predicted by CT and EUS in 90% (77/86) and 84% (72/86), respectively. In patients with a visible mass on CT, suspected for pancreatic or periampullary cancer, EUS has no additional diagnostic value, does not influence the decision to perform laparotomy and should therefore not be performed routinely. In patients without a visible mass on CT, EUS is useful to confirm the presence of a tumor. Copyright © 2014 IAP and EPC. Published by Elsevier B.V. All rights reserved.

Principal component analysis of the CT density histogram to generate parametric response maps of COPD

NASA Astrophysics Data System (ADS)

Zha, N.; Capaldi, D. P. I.; Pike, D.; McCormack, D. G.; Cunningham, I. A.; Parraga, G.

2015-03-01

Pulmonary x-ray computed tomography (CT) may be used to characterize emphysema and airways disease in patients with chronic obstructive pulmonary disease (COPD). One analysis approach - parametric response mapping (PMR) utilizes registered inspiratory and expiratory CT image volumes and CT-density-histogram thresholds, but there is no consensus regarding the threshold values used, or their clinical meaning. Principal-component-analysis (PCA) of the CT density histogram can be exploited to quantify emphysema using data-driven CT-density-histogram thresholds. Thus, the objective of this proof-of-concept demonstration was to develop a PRM approach using PCA-derived thresholds in COPD patients and ex-smokers without airflow limitation. Methods: Fifteen COPD ex-smokers and 5 normal ex-smokers were evaluated. Thoracic CT images were also acquired at full inspiration and full expiration and these images were non-rigidly co-registered. PCA was performed for the CT density histograms, from which the components with the highest eigenvalues greater than one were summed. Since the values of the principal component curve correlate directly with the variability in the sample, the maximum and minimum points on the curve were used as threshold values for the PCA-adjusted PRM technique. Results: A significant correlation was determined between conventional and PCA-adjusted PRM with 3He MRI apparent diffusion coefficient (p<0.001), with CT RA950 (p<0.0001), as well as with 3He MRI ventilation defect percent, a measurement of both small airways disease (p=0.049 and p=0.06, respectively) and emphysema (p=0.02). Conclusions: PRM generated using PCA thresholds of the CT density histogram showed significant correlations with CT and 3He MRI measurements of emphysema, but not airways disease.

Value of repeat CT scans in low back pain and radiculopathy.

PubMed

Schroeder, Josh E; Barzilay, Yair; Kaplan, Leon; Itshayek, Eyal; Hiller, Nurith

2016-02-01

We assessed the clinical value of repeat spine CT scan in 108 patients aged 18-60 years who underwent repeat lumbar spine CT scan for low back pain or radiculopathy from January 2008 to December 2010. Patients with a neoplasm or symptoms suggesting underlying disease were excluded from the study. Clinical data was retrospectively reviewed. Index examinations and repeat CT scan performed at a mean of 24.3 ± 11.3 months later were compared by a senior musculoskeletal radiologist. Disc abnormalities (herniation, sequestration, bulge), spinal stenosis, disc space narrowing, and bony changes (osteophytes, fractures, other changes) were documented. Indications for CT scan were low back pain (60 patients, 55%), radiculopathy (46 patients, 43%), or nonspecific back pain (two patients, 2%). A total of 292 spine pathologies were identified in 98 patients (90.7%); in 10 patients (9.3%) no spine pathology was seen on index or repeat CT scan. At repeat CT scan, 269/292 pathologies were unchanged (92.1%); 10/292 improved (3.4%), 8/292 worsened (2.8%, disc herniation or spinal stenosis), and five new pathologies were identified. No substantial therapeutic change was required in patients with worsened or new pathology. Added diagnostic value from repeat CT scan performed within 2-3 years was rare in patients suffering chronic or recurrent low back pain or radiculopathy, suggesting that repeat CT scan should be considered only in patients with progressive neurologic deficits, new neurologic complaints, or signs implying serious underlying conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Added Value of SPECT/CT in the Evaluation of Benign Bone Diseases of the Appendicular Skeleton.

PubMed

Abikhzer, Gad; Srour, Saher; Keidar, Zohar; Bar-Shalom, Rachel; Kagna, Olga; Israel, Ora; Militianu, Daniela

2016-04-01

Bone scintigraphy is a sensitive technique to detect altered bone mineralization but has limited specificity. The use of SPECT/CT has improved significantly the diagnostic accuracy of bone scintigraphy, in patients with cancer as well as in evaluation of benign bone disease. It provides precise localization and characterization of tracer-avid foci, shortens the diagnostic workup, and decreases patient anxiety. Through both the SPECT and the CT components, SPECT/CT has an incremental value in characterizing benign bone lesions, specifically in the appendicular skeleton, as illustrated by present case series.

Composite Aircraft Life Cycle Cost Estimating Model

DTIC Science & Technology

2011-03-01

X. The masked fit of the lines are as follows: • Part Count Percentage Reduction for Design hours ( HRE %) = • Part Count Percentage Reduction...multiplied by the respective labor rate (LR). Currently, CT is a percentage of total non- recurring development cost. HRE corresponds to recurring...Empty Weight Velocity RENGR HRE CRE 46 Figure 14: Non-Recurring Engineering CER Currently, CT is a percentage of non-recurring development

Comparison of three-view thoracic radiography and computed tomography for detection of pulmonary nodules in dogs with neoplasia.

PubMed

Armbrust, Laura J; Biller, David S; Bamford, Aubrey; Chun, Ruthanne; Garrett, Laura D; Sanderson, Michael W

2012-05-01

To compare the detection of pulmonary nodules by use of 3-view thoracic radiography and CT in dogs with confirmed neoplasia. Prospective case series. 33 dogs of various breeds. 3 interpreters independently evaluated 3-view thoracic radiography images. The location and size of pulmonary nodules were recorded. Computed tomographic scans of the thorax were obtained and evaluated by a single interpreter. The location, size, margin, internal architecture, and density of pulmonary nodules were recorded. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for thoracic radiography (with CT as the gold standard). 21 of 33 (64%) dogs had pulmonary nodules or masses detected on CT. Of the dogs that had positive CT findings, 17 of 21 (81%) had pulmonary nodules or masses detected on radiographs by at least 1 interpreter. Sensitivity of radiography ranged from 71% to 95%, and specificity ranged from 67% to 92%. Radiography had a positive predictive value of 83% to 94% and a negative predictive value of 65% to 89%. The 4 dogs that were negative for nodules on thoracic radiography but positive on CT were all large-breed to giant-breed dogs with osteosarcoma. CT was more sensitive than radiography for detection of pulmonary nodules. This was particularly evident in large-breed to giant-breed dogs. Thoracic CT is recommended in large-breed to giant-breed dogs with osteosarcoma if the detection of pulmonary nodules will change treatment.

Selection and evaluation of reference genes for expression studies with quantitative PCR in the model fungus Neurospora crassa under different environmental conditions in continuous culture.

PubMed

Cusick, Kathleen D; Fitzgerald, Lisa A; Pirlo, Russell K; Cockrell, Allison L; Petersen, Emily R; Biffinger, Justin C

2014-01-01

Neurospora crassa has served as a model organism for studying circadian pathways and more recently has gained attention in the biofuel industry due to its enhanced capacity for cellulase production. However, in order to optimize N. crassa for biotechnological applications, metabolic pathways during growth under different environmental conditions must be addressed. Reverse-transcription quantitative PCR (RT-qPCR) is a technique that provides a high-throughput platform from which to measure the expression of a large set of genes over time. The selection of a suitable reference gene is critical for gene expression studies using relative quantification, as this strategy is based on normalization of target gene expression to a reference gene whose expression is stable under the experimental conditions. This study evaluated twelve candidate reference genes for use with N. crassa when grown in continuous culture bioreactors under different light and temperature conditions. Based on combined stability values from NormFinder and Best Keeper software packages, the following are the most appropriate reference genes under conditions of: (1) light/dark cycling: btl, asl, and vma1; (2) all-dark growth: btl, tbp, vma1, and vma2; (3) temperature flux: btl, vma1, act, and asl; (4) all conditions combined: vma1, vma2, tbp, and btl. Since N. crassa exists as different cell types (uni- or multi-nucleated), expression changes in a subset of the candidate genes was further assessed using absolute quantification. A strong negative correlation was found to exist between ratio and threshold cycle (CT) values, demonstrating that CT changes serve as a reliable reflection of transcript, and not gene copy number, fluctuations. The results of this study identified genes that are appropriate for use as reference genes in RT-qPCR studies with N. crassa and demonstrated that even with the presence of different cell types, relative quantification is an acceptable method for measuring gene expression changes during growth in bioreactors.

Effect of artificial aging on the bond durability of fissure sealants.

PubMed

Yun, Xiaofei; Li, Wei; Ling, Chen; Fok, Alex

2013-06-01

To evaluate the effect of artificial aging on the bond durability of fissure sealants in vitro. Twenty bovine incisors received 4 different sealant treatments and were divided into four groups: 1. Ultraseal XT plus (UX); 2. Enamel Loc (EL); 3. 35% phosphoric acid plus Enamel Loc (PEL); 4. Adper Prompt L-Pop plus Clinpro (PPC). Beam-shaped specimens were prepared and randomly divided into three subgroups. One subgroup underwent the microtensile bond strength (µTBS) test after 24-h storage in 37°C water. The other two subgroups were also subjected to the microtensile bond strength test after 5000 and 10,000 thermal cycles, respectively. Another twelve intact human third molars were sealed using 1 of 3 methods and were divided into 3 groups of 4 each: 1. Ultraseal XT plus; 2. Adper Prompt L-Pop plus Clinpro; and 3. Enamel Loc. Two specimens from each group were immersed in a 50% silver nitrate solution for 24 h, followed by exposure to fluorescent light for 8 h, before being scanned in a micro-CT (microcomputer tomography) machine. The other two were handled in the same way after undergoing 10,000 thermal cycles. The CT images obtained were evaluated. All samples from the EL group were broken during preparation, so no µTBS results were available. After 5000 thermal cycles, the bond strengths of the three other groups (UX, PEL, PPC) decreased significantly (p < 0.05). Longer thermocycling (10,000 cycles) resulted in more decreases in µTBS for group PEL and PPC, while the strength of the UX group remained relatively unchanged. After thermocycling, considerable silver penetration could be seen at the sealant/enamel interface of the EL group in micro-CT images. The etch-and-rinse procedure for sealant application promotes higher bond strength under artificial aging. Micro-CT, a nondestructive analytical tool, may be used to evaluate the sealant/enamel interface effectively.

Cancer screening with whole-body PET/CT for healthy asymptomatic people in Japan: re-evaluation of its test validity and radiation exposure.

PubMed

Ghotbi, Nader; Iwanaga, Masako; Ohtsuru, Akira; Ogawa, Yoji; Yamashita, Shunichi

2007-01-01

The use of Positron Emission Tomography (PET) or PET/CT for voluntary cancer screening of asymptomatic individuals is becoming common in Japan, though the utility of such screening is still controversial. This study estimated the general test validity and effective radiation dose for PET/CT cancer screening of healthy Japanese people by evaluating four standard indices (sensitivity, specificity, positive/negative predictive values), and predictive values with including prevalence for published literature and simulation-based Japanese data. CT and FDG-related dosage data were gathered from the literature and then extrapolated to the scan parameters at a model PET center. We estimated that the positive predictive value was only 3.3% in the use of PET/CT for voluntary cancer screening of asymptomatic Japanese individuals aged 50-59 years old, whose average cancer prevalence was 0.5%. The total effective radiation dose of a single whole-body PET/CT scan was estimated to be 6.34 to 9.48 mSv for the average Japanese individual, at 60 kg body weight. With PET/CT cancer screening in Japan, many healthy volunteers screened as false positive are exposed to at least 6.34 mSv without getting any real benefit. More evaluation concerning the justification of applying PET/CT for healthy people is necessary.

The Value of Restaging With Chest and Abdominal CT/MRI Scan After Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer.

PubMed

Liu, Guo-Chen; Zhang, Xu; Xie, E; An, Xin; Cai, Pei-Qiang; Zhu, Ying; Tang, Jing-Hua; Kong, Ling-Heng; Lin, Jun-Zhong; Pan, Zhi-Zhong; Ding, Pei-Rong

2015-11-01

Little was known with regard to the value of preoperative systemic restaging for patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (CRT). This study was designed to evaluate the role of chest and abdominal computed tomography (CT) scan or magnetic resonance imaging (MRI) on preoperative restaging in LARC after neoadjuvant CRT and to assess the impact on treatment strategy.Between January 2007 and April 2013, 386 newly diagnosed consecutive patients with LARC who underwent neoadjuvant CRT and received restaging with chest and abdominal CT/MRI scan were included. Imaging results before and after CRT were analyzed.Twelve patients (3.1%) (6 liver lesions, 2 peritoneal lesions, 2 distant lymph node lesions, 1 lung lesions, 1 liver and lung lesions) were diagnosed as suspicious metastases on the restaging scan after radiotherapy. Seven patients (1.8%) were confirmed as metastases by pathology or long-term follow-up. The treatment strategy was changed in 5 of the 12 patients as a result of restaging CT/MRI findings. Another 10 patients (2.6%) who present with normal restaging imaging findings were diagnosed as metastases intra-operatively. The sensitivity, specificity accuracy, negative predictive value, and positive predictive values of restaging CT/MRI was 41.4%, 98.6%, 58.3%, and 97.3%, respectively.The low incidence of metastases and minimal consequences for the treatment plan question the clinical value of routine restaging of chest and abdomen after neoadjuvant CRT. Based on this study, a routine restaging CT/MRI of chest and abdomen in patients with rectal cancer after neoadjuvant CRT is not advocated, carcino-embryonic antigen (CEA) -guided CT/MRI restaging might be an alternative.

Evaluation of quantitative parameters for distinguishing pheochromocytoma from other adrenal tumors.

PubMed

Ohno, Youichi; Sone, Masakatsu; Taura, Daisuke; Yamasaki, Toshinari; Kojima, Katsutoshi; Honda-Kohmo, Kyoko; Fukuda, Yorihide; Matsuo, Koji; Fujii, Toshihito; Yasoda, Akihiro; Ogawa, Osamu; Inagaki, Nobuya

2018-03-01

Adrenal tumors are increasingly found incidentally during imaging examinations. It is important to distinguish pheochromocytomas from other adrenal tumors because of the risk of hypertensive crisis. Although catecholamines and their metabolites are generally used to diagnose pheochromocytoma, false-positive test results are common. An effective screening method to distinguish pheochromocytoma from adrenal incidentalomas is needed. We analyzed 297 consecutive patients with adrenal incidentalomas. Our findings included 162 non-functioning tumors, 47 aldosterone-producing adenomas, 26 metastases, 22 cases of subclinical Cushing's syndrome, 21 pheochromocytomas, 12 cases of Cushing's syndrome, and 7 adrenocortical cancers. We checked quantitative parameters such as age, blood, and urine catecholamines and their metabolites, neuron-specific enolase, size and computed tomography (CT) attenuation values. Among catecholamine-related parameters, the sum of urine metanephrine and normetanephrine (urineMNM) levels produced the highest area under the receiver operating characteristic curve regarding discrimination of pheochromocytoma from other lesions. Size and CT attenuation values also differed significantly. However, size was correlated with catecholamine levels. CT attenuation was not correlated with other factors. The optimal thresholds were 19 Hounsfield units (HU) for CT attenuation (sensitivity, 100%; specificity, 60%) and 0.43 mg/24 h for urineMNM (sensitivity, 89%; specificity, 96%). No pheochromocytomas were evident when CT attenuation values were under 19 HU. Even in adrenal tumors with CT attenuation values ≥ 19 HU, when urineMNM was < 0.43 mg/24 h, the frequency of pheochromocytoma was only 4.3%, when urineMNM was ≥ 0.43 mg/24 h, the frequency of pheochromocytoma was 93% and when urineMNM was > 0.77 mg/24 h the frequency of pheochromocytoma was 100%. CT attenuation value and urineMNM represented the most useful combination for diagnosis of pheochromocytoma.

Using Helical CT to Predict Stone Fragility in Shock Wave Lithotripsy (SWL)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, James C. Jr.; Zarse, Chad A.; Jackson, Molly E.

2007-04-05

Great variability exists in the response of urinary stones to SWL, and this is true even for stones composed of the same mineral. Efforts have been made to predict stone fragility to shock waves using computed tomography (CT) patient images, but most work to date has focused on the use of stone CT number (i.e., Hounsfield units). This is an easy number to measure on a patient stone, but its value depends on a number of factors, including the relationship of the size of the stone to me resolution (i.e., the slicewidth) of the CT scan. Studies that have shownmore » a relationship between stone CT number and failure in SWL are reviewed, and all are shown to suffer from error due to stone size, which was not accounted for in the use of Hounsfield unit values. Preliminary data are then presented for a study of calcium oxalate monohydrate (COM) stones, in which stone structure-rather than simple CT number values-is shown to correlate with fragility to shock waves. COM stones that were observed to have structure by micro CT (e.g., voids, apatite regions, unusual shapes) broke to completion in about half the number of shock waves required for COM stones that were observed to be homogeneous in structure by CT. This result suggests another direction for the use of CT in predicting success of SWL: the use of CT to view stone structure, rather than simply measuring stone CT number. Viewing stone structure by CT requires the use of different viewing windows than those typically used for examining patient scans, but much research to date indicates that stone structure can be observed in the clinical setting. Future clinical studies will need to be done to verify the relationship between stone structure observed by CT and stone fragility in SWL.« less

Computed Tomography Features of Benign and Malignant Calcified Thyroid Nodules: A Single-Center Study.

PubMed

Kim, Donghyun; Kim, Dong Wook; Heo, Young Jin; Baek, Jin Wook; Lee, Yoo Jin; Park, Young Mi; Baek, Hye Jin; Jung, Soo Jin

No previous studies have investigated thyroid calcification on computed tomography (CT) quantitatively by using Hounsfield unit (HU) values. This study aimed to analyze quantitative HU values of thyroid calcification on preoperative neck CT and to assess the characteristics of benign and malignant calcified thyroid nodules (CTNs). Two hundred twenty patients who underwent neck CT before thyroid surgery from January 2015 to June 2016 were included. On soft-tissue window CT images, CTNs with calcified components of 3 mm or larger in minimum diameter were included in this study. The HU values and types of CTNs were determined and analyzed. Of 61 CTNs in 49 patients, there were 42 malignant nodules and 19 benign nodules. The mean largest diameter of the calcified component was 5.3 (2.5) mm (range, 3.1-17.1 mm). A statistically significant difference was observed in the HU values of calcified portions between benign and malignant CTNs, whereas there was no significant difference in patient age or sex or in the size, location, or type of each CTN. Of the 8 CTNs with pure calcification, 3 exhibited a honeycomb pattern on bone window CT images, and these 3 CTNs were all diagnosed as papillary thyroid carcinoma on histopathological examination. Hounsfield unit values of CTNs may be helpful for differentiating malignancy from benignity.

[Effect of Charge-Transfer Complex on Ultraviolet-Visible (UV-Vis) Absorption Property of Chromophoric Dissolved Organic Matter (CDOM) in Waters of Typical Water-Level Fluctuation Zones of the Three Gorges Reservoir Areas].

PubMed

Jiang, Tao; Liang, Jian; Zhang, Mu-xue; Wang, Ding-yong; Wei, Shi-qiang; Lu, Song

2016-02-15

As an important fraction of dissolved organic matter (DOM), chromophoric dissolved organic matter (CDOM) plays a key role in decision of the optical properties and photogeochemistry of DOM, and further affects pollutant fate and global carbon cycle. These optical properties are ascribed to two chromophoric systems including superposition of individual chromophores and charge-transfer (CT) complexation between electron donor (e.g., phenols and indoles) and acceptor (e.g., quinones and other oxidized aromatics) in DOM structures. Thus in this study, based on the "double-chromophoric system" model, DOM samples from four typical water-level fluctuation zones of Three Gorges Reservoir (TGR) areas were selected, to investigate the effect and contribution of charge-transfer complex to ultraviolet-visible (UV-Vis) absorption property of CDOM. Using NaBH, reduction method, original featureless absorption curve was classified into two independent curves caused by individual chromophoric group, which were derived from a simple superposition of independent chromophore and charge-transfer complex, respectively. Also, the changes in curve properties and specific parameters before and after NaBH4 reduction were compared. The results showed that in all DOM samples from the four sites of TGR, more than 35% of absorption was attributed from CT complex. Shibaozhai of Zhongxian and Zhenxi of Fuling showed the highest proportion ( > 50%). It suggested that the role of CT complex in CDOM property could not be neglected. After removal of CT complex, absorption curve showed blue-shift and CDOM concentration [a (355)] decreased significantly. Meanwhile, because of deforming of bonds by reduction, DOM structures became more dispersive and the molecular size was decreased, resulting in the lower spectral slope (S) observed, which evidentially supported that the supermolecular association structure of DOM was self-assembled through CT complex. Meanwhile, deceasing hydrophobic components led to decreased apparent aromaticity (lower SUVA values), whereas specific parameters including SUVA, CDOM and SR still were applicable for comparison among different DOM samples instead of the same sample without consideration of "double-cbromopboric system" model involving tbe role of CT complex. Comparatively, S(275-295) was dynamic due to tbe impact of CT effect. Furtbermore, establisbing DOC estimation model by short-wavelength range of CDOM was recommended because of its stability despite of CT complex.

Contrast-enhanced small-animal PET/CT in cancer research: strong improvement of diagnostic accuracy without significant alteration of quantitative accuracy and NEMA NU 4-2008 image quality parameters.

PubMed

Lasnon, Charline; Quak, Elske; Briand, Mélanie; Gu, Zheng; Louis, Marie-Hélène; Aide, Nicolas

2013-01-17

The use of iodinated contrast media in small-animal positron emission tomography (PET)/computed tomography (CT) could improve anatomic referencing and tumor delineation but may introduce inaccuracies in the attenuation correction of the PET images. This study evaluated the diagnostic performance and accuracy of quantitative values in contrast-enhanced small-animal PET/CT (CEPET/CT) as compared to unenhanced small animal PET/CT (UEPET/CT). Firstly, a NEMA NU 4-2008 phantom (filled with 18F-FDG or 18F-FDG plus contrast media) and a homemade phantom, mimicking an abdominal tumor surrounded by water or contrast media, were used to evaluate the impact of iodinated contrast media on the image quality parameters and accuracy of quantitative values for a pertinent-sized target. Secondly, two studies in 22 abdominal tumor-bearing mice and rats were performed. The first animal experiment studied the impact of a dual-contrast media protocol, comprising the intravenous injection of a long-lasting contrast agent mixed with 18F-FDG and the intraperitoneal injection of contrast media, on tumor delineation and the accuracy of quantitative values. The second animal experiment compared the diagnostic performance and quantitative values of CEPET/CT versus UEPET/CT by sacrificing the animals after the tracer uptake period and imaging them before and after intraperitoneal injection of contrast media. There was minimal impact on IQ parameters (%SDunif and spillover ratios in air and water) when the NEMA NU 4-2008 phantom was filled with 18F-FDG plus contrast media. In the homemade phantom, measured activity was similar to true activity (-0.02%) and overestimated by 10.30% when vials were surrounded by water or by an iodine solution, respectively. The first animal experiment showed excellent tumor delineation and a good correlation between small-animal (SA)-PET and ex vivo quantification (r2 = 0.87, P < 0.0001). The second animal experiment showed a good correlation between CEPET/CT and UEPET/CT quantitative values (r2 = 0.99, P < 0.0001). Receiver operating characteristic analysis demonstrated better diagnostic accuracy of CEPET/CT versus UEPET/CT (senior researcher, area under the curve (AUC) 0.96 versus 0.77, P = 0.004; junior researcher, AUC 0.78 versus 0.58, P = 0.004). The use of iodinated contrast media for small-animal PET imaging significantly improves tumor delineation and diagnostic performance, without significant alteration of SA-PET quantitative accuracy and NEMA NU 4-2008 IQ parameters.

Value of 18F-FDG PET/CT in diagnosing chronic Q fever in patients with central vascular disease.

PubMed

Hagenaars, J C J P; Wever, P C; Vlake, A W; Renders, N H M; van Petersen, A S; Hilbink, M; de Jager-Leclercq, M G L; Moll, F L; Koning, O H J; Hoekstra, C J

2016-08-01

The aim of this study is to describe the value of 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in diagnosing chronic Q fever in patients with central vascular disease and the added value of 18F-FDG PET/CT in the diagnostic combination strategy as described in the Dutch consensus guideline for diagnosing chronic Q fever. 18F-FDG PET/CT was performed in patients with an abdominal aortic aneurysm or aorto-iliac reconstruction and chronic Q fever, diagnosed by serology and positive PCR for Coxiella burnetii DNA in blood and/or tissue (PCR-positive study group). Patients with an abdominal aortic aneurysm or aorto-iliac reconstruction without clinical and serological findings indicating Q fever infection served as a control group. Patients with a serological profile of chronic Q fever and a negative PCR in blood were included in additional analyses (PCR-negative study group). Thirteen patients were evaluated in the PCR-positive study group and 22 patients in the control group. 18F-FDG PET/CT indicated vascular infection in 6/13 patients in the PCR-positive study group and 2/22 patients in the control group. 18F-FDG PET/CT demonstrated a sensitivity of 46% (95% CI: 23-71%), specificity of 91% (95% CI: 71-99%), positive predictive value of 75% (95% CI:41-93%) and negative predictive value of 74% (95% CI: 55-87%). In the PCR-negative study group, 18F-FDG PET/CT was positive in 10/20 patients (50%). The combination of 18F-FDG PET/CT, as an imaging tool for identifying a focus of infection, and Q fever serology is a valid diagnostic strategy for diagnosing chronic Q fever in patients with central vascular disease.

Is there any significance of lung cancer histology to compare the diagnostic accuracies of (18)F-FDG-PET/CT and (99m)Tc-MDP BS for the detection of bone metastases in advanced NSCLC?

PubMed

Inal, Ali; Kaplan, Muhammed Ali; Kucukoner, Mehmet; Urakcı, Zuhat; Dostbil, Zeki; Komek, Hail; Onder, Hakan; Tasdemir, Bekir; Isıkdogan, Abdurrahman

2014-01-01

Bone scintigraphy (BS) and fluorine-18 deoxyglucose positron emission tomography computed tomography ((18)F-FDG-PET/CT) are widely used for the detection of bone involvement. The optimal imaging modality for the detection of bone metastases in histological subgroups of non-small cell lung cancer (NSCLC) remains ambiguous. The aim of this study was to compare the efficacy of (18)F-FDG-PET/C and 99mTc-methylene diphosphonate ((99m)Tc-MDP) BS in the detection of bone metastases of patients in NSCLC. Specifically, we compared the diagnostic accuracies of these imaging techniques evaluating bone metastasis in histological subgroups of NSCLC. Fifty-three patients with advanced NSCLC, who had undergone both (18)F-FDG-PET/CT and BS and were eventually diagnosed as having bone metastasis, were enrolled in this retrospective study. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of (18)F-FDG-PET/CT and BS were 90.4%, 99.4%, 98.1%, 96.6%, 97.0% and 84.6%, 93.1%, 82.5%, 93.2, 90.8%, respectively. The κ statistics were calculated for (18)F-FDG-PET/CT and BS. The κ-value was 0.67 between (18)F-FDG-PET/CT and BS in all patients. On the other hand, the κ-value was 0.65 in adenocarcinoma, and 0.61 in squamous cell carcinoma between (18)F-FDG-PET/CT and BS. The κ-values suggested excellent agreement between all patients and histological subgroups of NSCLC. (18)F-FDG-PET/CT was more favorable than BS in the screening of metastatic bone lesions, but the trend did not reach statistical significance in all patients and histological subgroups of NSCLC. Our results need to be validated in prospective and larger study clinical trials to further clarify this topic.

Processing of CT sinograms acquired using a VRX detector

NASA Astrophysics Data System (ADS)

Jordan, Lawrence M.; DiBianca, Frank A.; Zou, Ping; Laughter, Joseph S.; Zeman, Herbert D.

2000-04-01

A 'variable resolution x-ray detector' (VRX) capable of resolving beyond 100 cycles/main a single dimension has been proposed by DiBianca, et al. The use of detectors of this design for computed-tomography (CT) imaging requires novel preprocessing of data to correct for the detector's non- uniform imaging characteristics over its range of view. This paper describes algorithms developed specifically to adjust VRX data for varying magnification, source-to-detector range and beam obliquity and to sharpen reconstructions by deconvolving the ray impulse function. The preprocessing also incorporates nonlinear interpolation of VRX raw data into canonical CT sinogram formats.

Usage of CT data in biomechanical research

NASA Astrophysics Data System (ADS)

Safonov, Roman A.; Golyadkina, Anastasiya A.; Kirillova, Irina V.; Kossovich, Leonid Y.

2017-02-01

Object of study: The investigation is focused on development of personalized medicine. The determination of mechanical properties of bone tissues based on in vivo data was considered. Methods: CT, MRI, natural experiments on versatile test machine Instron 5944, numerical experiments using Python programs. Results: The medical diagnostics methods, which allows determination of mechanical properties of bone tissues based on in vivo data. The series of experiments to define the values of mechanical parameters of bone tissues. For one and the same sample, computed tomography (CT), magnetic resonance imaging (MRI), ultrasonic investigations and mechanical experiments on single-column test machine Instron 5944 were carried out. The computer program for comparison of CT and MRI images was created. The grayscale values in the same points of the samples were determined on both CT and MRI images. The Haunsfield grayscale values were used to determine rigidity (Young module) and tensile strength of the samples. The obtained data was compared to natural experiments results for verification.

TU-C-12A-11: Comparisons Between Cu-ATSM PET and DCE-CT Kinetic Parameters in Canine Sinonasal Tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

La Fontaine, M; Bradshaw, T; Kubicek, L

2014-06-15

Purpose: Regions of poor perfusion within tumors may be associated with higher hypoxic levels. This study aimed to test this hypothesis by comparing measurements of hypoxia from Cu-ATSM PET to vasculature kinetic parameters from DCE-CT kinetic analysis. Methods: Ten canine patients with sinonasal tumors received one Cu-ATSM PET/CT scan and three DCE-CT scans prior to treatment. Cu-ATSM PET/CT and DCE-CT scans were registered and resampled to matching voxel dimensions. Kinetic analysis was performed on DCE-CT scans and for each patient, the resulting kinetic parameter values from the three DCE-CT scans were averaged together. Cu-ATSM SUVs were spatially correlated (r{sub spatial})more » on a voxel-to-voxel basis against the following DCE-CT kinetic parameters: transit time (t{sub 1}), blood flow (F), vasculature fraction (v{sub 1}), and permeability (PS). In addition, whole-tumor comparisons were performed by correlating (r{sub ROI}) the mean Cu-ATSM SUV (SUV{sub mean}) with median kinetic parameter values. Results: The spatial correlations (r{sub spatial}) were poor and ranged from -0.04 to 0.21 for all kinetic parameters. These low spatial correlations may be due to high variability in the DCE-CT kinetic parameter voxel values between scans. In our hypothesis, t{sub 1} was expected to have a positive correlation, while F was expected to have a negative correlation to hypoxia. However, in wholetumor analysis the opposite was found for both t{sub 1} (r{sub ROI} = -0.25) and F (r{sub ROI} = 0.56). PS and v{sub 1} may depict angiogenic responses to hypoxia and found positive correlations to Cu-ATSM SUV for PS (r{sub ROI} = 0.41), and v{sub 1} (r{sub ROI} = 0.57). Conclusion: Low spatial correlations were found between Cu-ATSM uptake and DCE-CT vasculature parameters, implying that poor perfusion is not associated with higher hypoxic regions. Across patients, the most hypoxic tumors tended to have higher blood flow values, which is contrary to our initial hypothesis. Funding: R01 CA136927.« less

FDG-PET/CT in autosomal dominant polycystic kidney disease patients with suspected cyst infection.

PubMed

Pijl, Jordy Pieter; Glaudemans, Andor W J M; Slart, Riemer H J A; Kwee, Thomas Christian

2018-04-13

Purpose: To determine the value of 18 F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) for diagnosing renal or hepatic cyst infection in patients with autosomal dominant polycystic kidney disease (ADPKD). Methods: This retrospective single-center study included all patients with ADPKD who underwent FDG-PET/CT because of suspected cyst infection between 2010 and 2017. Results: Thirty FDG-PET/CT scans of thirty individual patients were included, of which 19 were positive for cyst infection. According to a previously established clinical and biochemical reference standard, FDG-PET/CT achieved sensitivity of 88.9%, specificity of 75.0%, positive predictive value of 84.2%, and negative predictive value of 81.8% for the diagnosis of cyst infection. In 5 cases, FDG-PET/CT suggested a different pathologic process that explained the symptoms, including pneumonia ( n = 1), generalized peritonitis ( n = 1), pancreatitis ( n = 1), colitis ( n = 1), and cholangitis ( n = 1). Total duration of hospital stay and duration between FDG-PET/CT scan and hospital discharge of patients with an FDG-PET/CT scan positive for cyst infection were significantly longer than those with a negative scan ( P = 0.005 and P = 0.009, respectively). Creatinine levels were significantly higher in patients with an FDG-PET/CT scan positive for cyst infection than in patients with a negative scan ( P = 0.015). Other comparisons of clinical parameters (age, gender, presence of fever (>38.5°C) for more than 3 days, abdominal pain, history of solid organ transplantation and nephrectomy, immune status), laboratory values (C-reactive protein level (CRP), leukocyte count, estimated glomerular filtration rate), and microbiologic results (blood and urine cultures) were not significantly different ( P = 0.13-1.00) between FDG-PET/CT-positive and -negative patients. Conclusion: FDG-PET/CT is a useful and recommendable (upfront) imaging modality for the evaluation of patients with ADPKD and suspected cyst infection. Copyright © 2018 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Added prognostic value of CT characteristics and IASLC/ATS/ERS histologic subtype in surgically resected lung adenocarcinomas.

PubMed

Suh, Young Joo; Lee, Hyun-Ju; Kim, Young Tae; Kang, Chang Hyun; Park, In Kyu; Jeon, Yoon Kyung; Chung, Doo Hyun

2018-06-01

Our study investigates the added value of computed tomography (CT) characteristics, histologic subtype classification of the International Association for the Study of Lung Cancer (IASLC)/the American Thoracic Society (ATS)/the European Respiratory Society (ERS), and genetic mutation for predicting postoperative prognoses of patients who received curative surgical resections for lung adenocarcinoma. We retrospectively enrolled 988 patients who underwent curative resection for invasive lung adenocarcinoma between October 2007 and December 2013. Cox's proportional hazard model was used to explore the risk of recurrence-free survival, based on the combination of conventional prognostic factors, CT characteristics, IASLC/ATS/ERS histologic subtype, and epidermal growth factor receptor (EGFR) mutations. Incremental prognostic values of CT characteristics, histologic subtype, and EGFR mutations over conventional risk factors were measured by C-statistics. During median follow-up period of 44.7 months (25th to 75th percentile 24.6-59.7 months), postoperative recurrence occurred in 248 patients (25.1%). In univariate Cox proportion hazard model, female sex, tumor size and stage, CT characteristics, and predominant histologic subtype were associated with tumor recurrence (P < 0.05). In multivariate Cox regression model adjusted for tumor size and stage, both CT characteristics and histologic subtype were independent tumor recurrence predictors (P < 0.05). Cox proportion hazard models combining CT characteristics or histologic subtype with size and tumor stage showed higher C-indices (0.763 and 0.767, respectively) than size and stage-only models (C-index 0.759, P > 0.05). CT characteristics and histologic subtype have relatively limited added prognostic values over tumor size and stage in surgically resected lung adenocarcinomas. Copyright © 2018 Elsevier B.V. All rights reserved.

Effective doses to patients undergoing thoracic computed tomography examinations.

PubMed

Huda, W; Scalzetti, E M; Roskopf, M

2000-05-01

The purpose of this study was to investigate how x-ray technique factors and effective doses vary with patient size in chest CT examinations. Technique factors (kVp, mAs, section thickness, and number of sections) were recorded for 44 patients who underwent a routine chest CT examination. Patient weights were recorded together with dimensions and mean Hounsfield unit values obtained from representative axial CT images. The total mass of directly irradiated patient was modeled as a cylinder of water to permit the computation of the mean patient dose and total energy imparted for each chest CT examination. Computed values of energy imparted during the chest CT examination were converted into effective doses taking into account the patient weight. Patient weights ranged from 4.5 to 127 kg, and half the patients in this study were children under 18 years of age. All scans were performed at 120 kVp with a 1 s scan time. The selected tube current showed no correlation with patient weight (r2=0.06), indicating that chest CT examination protocols do not take into account for the size of the patient. Energy imparted increased with increasing patient weight, with values of energy imparted for 10 and 70 kg patients being 85 and 310 mJ, respectively. The effective dose showed an inverse correlation with increasing patient weight, however, with values of effective dose for 10 and 70 kg patients being 9.6 and 5.4 mSv, respectively. Current CT technique factors (kVp/mAs) used to perform chest CT examinations result in relatively high patient doses, which could be reduced by adjusting technique factors based on patient size.

High-Resolution Three-Dimensional Computed Tomography for Assessing Complications Related to Intrathecal Drug Delivery.

PubMed

Morgalla, Matthias; Fortunato, Marcos; Azam, Ala; Tatagiba, Marcos; Lepski, Guillherme

2016-07-01

The assessment of the functionality of intrathecal drug delivery (IDD) systems remains difficult and time-consuming. Catheter-related problems are still very common, and sometimes difficult to diagnose. The aim of the present study is to investigate the accuracy of high-resolution three-dimensional computed tomography (CT) in order to detect catheter-related pump dysfunction. An observational, retrospective investigation. Academic medical center in Germany. We used high-resolution three dimensional (3D) computed tomography with volume rendering technique (VRT) or fluoroscopy and conventional axial-CT to assess IDD-related complications in 51 patients from our institution who had IDD systems implanted for the treatment of chronic pain or spasticity. Twelve patients (23.5%) presented a total of 22 complications. The main type of complication in our series was catheter-related (50%), followed by pump failure, infection, and inappropriate refilling. Fluoroscopy and conventional CT were used in 12 cases. High-resolution 3D CT VRT scan was used in 35 instances with suspected yet unclear complications. Using 3D-CT (VRT) the sensitivity was 58.93% - 100% (CI 95%) and the specificity 87.54% - 100% (CI 95%).The positive predictive value was 58.93% - 100% (CI 95%) and the negative predictive value: 87.54% - 100% (CI 95%).Fluoroscopy and axial CT as a combined diagnostic tool had a sensitivity of 8.3% - 91.7% (CI 95%) and a specificity of 62.9% - 100% (CI 95%). The positive predictive value was 19.29% - 100% (CI 95%) and the negative predictive value: 44.43% - 96.89% (CI 95%). This study is limited by its observational design and the small number of cases. High-resolution 3D CT VRT is a non- invasive method that can identify IDD-related complications with more precision than axial CT and fluoroscopy.

18F-FDG PET/CT for Monitoring Response of Merkel Cell Carcinoma to the Novel Programmed Cell Death Ligand 1 Inhibitor Avelumab.

PubMed

Eshghi, Naghmehossadat; Lundeen, Tamara F; MacKinnon, Lea; Avery, Ryan; Kuo, Phillip H

2018-05-01

An 85-year-old man with stage IIIA Merkel cell carcinoma of the left arm was initially treated with local excision and axillary node dissection followed by radiation therapy. Eight months after surgery, whole-body FDG PET/CT demonstrated intensely hypermetabolic hepatic metastases and abdominal lymphadenopathy. Given his age and comorbidities, he was considered a poor candidate for chemotherapy, and therefore the novel programmed cell death ligand 1 inhibitor avelumab was initiated. FDG PET/CT after 4 cycles showed complete resolution of hepatic and nodal metastases. Whole-body FDG PET/CT can be used for monitoring response of multisystem metastases from Merkel cell carcinoma to active immunotherapy.

Diagnostic value of a pancreatic mass on computed tomography in patients undergoing pancreatoduodenectomy for presumed pancreatic cancer.

PubMed

Gerritsen, Arja; Bollen, Thomas L; Nio, C Yung; Molenaar, I Quintus; Dijkgraaf, Marcel G W; van Santvoort, Hjalmar C; Offerhaus, G Johan; Brosens, Lodewijk A; Biermann, Katharina; Sieders, Egbert; de Jong, Koert P; van Dam, Ronald M; van der Harst, Erwin; van Goor, Harry; van Ramshorst, Bert; Bonsing, Bert A; de Hingh, Ignace H; Gerhards, Michael F; van Eijck, Casper H; Gouma, Dirk J; Borel Rinkes, Inne H M; Busch, Olivier R C; Besselink, Marc G H

2015-07-01

Previous studies have shown that 5-14% of patients undergoing pancreatoduodenectomy for suspected malignancy ultimately are diagnosed with benign disease. A "pancreatic mass" on computed tomography (CT) is considered to be the strongest predictor of malignancy, but studies describing its diagnostic value are lacking. The aim of this study was to determine the diagnostic value of a pancreatic mass on CT in patients with presumed pancreatic cancer, as well as the interobserver agreement among radiologists and the additional value of reassessment by expert-radiologists. Reassessment of preoperative CT scans was performed within a previously described multicenter retrospective cohort study in 344 patients undergoing pancreatoduodenectomy for suspected malignancy (2003-2010). Preoperative CT scans were reassessed by 2 experienced abdominal radiologists separately and subsequently in a consensus meeting, after defining a pancreatic mass as "a measurable space occupying soft tissue density, except for an enlarged papilla or focal steatosis". CT scans of 86 patients with benign and 258 patients with (pre)malignant disease were reassessed. In 66% of patients a pancreatic mass was reported in the original CT report, versus 48% and 50% on reassessment by the 2 expert radiologists separately and 44% in consensus (P < .001 vs original report). Interobserver agreement between the original CT report and expert consensus was fair (kappa = 0.32, 95% confidence interval 0.23-0.42). Among both expert-radiologists agreement was moderate (kappa = 0.47, 95% confidence interval 0.38-0.56), with disagreement on the presence of a pancreatic mass in 29% of cases. The specificity for malignancy of pancreatic masses identified in expert consensus was twice as high compared with the original CT report (87% vs 42%, respectively). Positive predictive value increased to 98% after expert consensus, but negative predictive value was low (12%). Clinicians need to be aware of potential considerable disagreement among radiologists about the presence of a pancreatic mass. The specificity for malignancy doubled by expert radiologist reassessment when a uniform definition of "pancreatic mass" was used. Copyright © 2015 Elsevier Inc. All rights reserved.

Efficacy of PET/CT to exclude leiomyoma in patients with lesions suspicious for uterine sarcoma on MRI.

PubMed

Kusunoki, Soshi; Terao, Yasuhisa; Ujihira, Takafumi; Fujino, Kazunari; Kaneda, Hiroshi; Kimura, Miki; Ota, Tsuyoshi; Takeda, Satoru

2017-08-01

To analyze the efficacy of positron emission tomography/computed tomography (PET/CT) for the diagnosis of uterine sarcoma. Thirty-four patients evaluated between January 2010 and March 2015 were retrospectively enrolled. All patients in whom uterine sarcoma was suspected based on contrast-enhanced magnetic resonance imaging (MRI) findings (heterogeneous, high signal intensity on T2-weighted images and/or high intensity on T1-weighted images) underwent PET/CT for further assessment. Patients were divided into 2 groups based on postoperative pathological findings: uterine sarcoma (n = 15) and leiomyoma (n = 19). The maximum standardized uptake value (SUVmax) of all lesions was measured using PET/CT; we calculated the optimal cutoff value for diagnosing sarcoma. The median SUVmax for uterine sarcoma and leiomyoma was 12 and 4.1, respectively; these values were significantly different. An SUVmax of greater than 7.5 was able to exclude leiomyoma with 80.8% sensitivity and 100% specificity (area under the curve, 95.3%). A cutoff SUVmax of 7.5 yields 100% specificity, and a cutoff SUVmax of 4.4 yields a 100% negative predictive value (NPV). The combination of PET/CT and lactate dehydrogenase (LDH) levels had a sensitivity of 86.6%, specificity of 100%, positive predictive value of 100%, and an NPV of 90.4%. No relation between histopathology or International Federation of Gynecology and Obstetrics (FIGO) stage and 18-fluoro-2-deoxy-d-glucose uptake value on PET/CT was seen. The surgical outcome trended toward a correlation with the SUVmax, although this was not statistically significant. In patients with MRI findings consistent with either uterine sarcoma or leiomyoma, PET/CT can decrease the false-positive rate by setting an optimal cutoff SUVmax of 7.5. Using this cutoff can avoid unnecessary surgery. Copyright © 2017. Published by Elsevier B.V.

[Clinical study on application of intermittent hemofiltration combined with hemoperfusion in the early stage of severe burn in the prevention and treatment of sepsis].

PubMed

Guo, Wanli; Lei, Jin; Duan, Peng; Ma, Xiaoming

2015-08-01

To investigate the effects of application of intermittent hemofiltration combined with hemoperfusion (HP) in the early stage of severe burn in the prevention and treatment of sepsis. Forty severely burned patients, admitted to our burn ward from June 2011 to March 2013, conforming to the study criteria, were divided into conventional treatment group (CT, n=20) and blood purification group (BP, n=20) according to the random number table. Patients in group CT received CT according to the accepted principles of treatment for a severe burn. Patients in group BP received CT and intermittent hemofiltration combined with HP once respectively on post injury day (PID) 3, 5, and 7, spanning 6 to 8 hours for each treatment. On PID 3, 5, 7, 10, and 14, body temperature, heart rate, and respiratory rate were recorded; white blood cell count (WBC), neutrophil granulocytes, blood urea nitrogen (BUN), and creatinine were determined; levels of IL-1, IL-6, TNF-α, and high-mobility group box 1 (HMGB1) in serum were determined by ELISA; level of LPS in serum was determined with the chromogenic substrate limulus amebocyte lysate method; level of procalcitonin (PCT) in serum was determined by double antibody sandwich immune chemiluminescence method. The symptoms and signs of sepsis were observed during the treatment. Data were processed with Fisher's exact test, chi-square test, analysis of variance for repeated measurement, and LSD-t test. (1) Except for that on PID 5, the mean body temperature of patients in group BP was significantly lower than that of group CT at each of the rest time points (with t values from 1.87 to 2.97, P values below 0.05). The heart rate was significantly slower in patients of group BP than in group CT from PID 3 to 14 (with t values from 1.78 to 3.59, P values below 0.05). Except for that on PID 3, the respiratory rate of patients in group BP was significantly slower than that of group CT at each of the rest time points (with t values from 1.93 to 2.85, P values below 0.05). (2) The levels of WBC, neutrophil granulocytes, BUN, and creatinine of patients in group BP were significantly lower than those of group CT (with t values from 1.78 to 4.23, P values below 0.05). (3) Except for that on PID 3, the level of IL-1 of patients in group BP was significantly lower than that of group CT at each of the rest time points (with t values from 1.97 to 4.16, P values below 0.05). Except for that on PID 7, the level of IL-6 of patients in group BP was significantly lower than that of group CT at each of the rest time points (with t values from 2.11 to 6.34, P values below 0.05). The levels of TNF-α and HMGB1 of patients in group BP were significantly lower than those of group CT from PID 3 to 14 (with t values from 1.98 to 5.29, P values below 0.05). (4) On PID 3, 5, 7, 10, and 14, the levels of LPS and PCT of patients in group BP were respectively (0.23 ± 0.07), (0.27 ± 0.09), (0.22 ± 0.06), (0.20 ± 0.08), (0.15 ± 0.07) EU/mL, and (0.44 ± 0.12), (0.67 ± 0.13), (0.74 ± 0.13), (0.64 ± 0.12), (0.71 ± 0.10) ng/mL, and they were lower than those of group CT [(0.37 ± 0.08), (0.45 ± 0.09), (0.56 ± 0.09), (0.48 ± 0.08), (0.40 ± 0.08) EU/mL, and (0.74 ± 0.11), (1.16 ± 0.12), (1.40 ± 0.13), (1.55 ± 0.15), (1.49 ± 0.14) ng/mL, with t values from 1.88 to 3.43, P values below 0.05]. (5) The incidence of sepsis of patients in group BP was obviously lower than that of group CT (χ² = 6.94, P<0.01). Intermittent hemofiltration combined with HP can effectively improve blood biochemical indexes and vital signs and reduce the occurrence of burn sepsis by decreasing the levels of proinflammatory cytokines, LPS, and PCT.

[Study of testicular cancer gene expression in samples of oral leukoplakia and squamous cell carcinoma of the mouth].

PubMed

Skorodumova, L O; Muraev, A A; Zakharova, E S; Shepelev, M V; Korobko, I V; Zaderenko, I A; Ivanov, S Iu; Gnuchev, N V; Georgiev, G P; Larin, S S

2012-01-01

Cancer-testis (CT) antigens are normally expressed mostly in human germ cells, there is also an aberrant expression in some tumor cells. This expression profile makes them potential tumor growth biomarkers and a promising target for tumor immunotherapy. Specificity of CT genes expression in oral malignant and potentially malignant diseases, e.g. oral leukoplakia, is not yet studied. Data on CT genes expression profile in leukoplakia would allow developing new diagnostic methods with potential value for immunotherapy and prophylaxis of leukoplakia malignization. In our study we compared CT genes expression in normal oral mucosa, oral leukoplakia and oral squamous cell carcinoma. We are the first to describe CT genes expression in oral leukoplakia without dysplasia. This findings make impossible differential diagnosis of oral leukoplakia and squamous cell carcinoma on the basis of CT genes expression. The prognostic value of CT genes expression is still unclear, therefore the longitudinal studies are necessary.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Shengqiang; Li, Jie; Yu, Junsheng, E-mail: jsyu@uestc.edu.cn

A color tuning index (I{sub CT}) parameter for evaluating the color change capability of color-tunable organic light-emitting diodes (CT-OLEDs) was proposed and formulated. And a series of CT-OLEDs, consisting of five different carrier/exciton adjusting interlayers (C/EALs) inserted between two complementary emitting layers, were fabricated and applied to disclose the relationship between I{sub CT} and C/EALs. The result showed that the trend of electroluminescence spectra behavior in CT-OLEDs has good accordance with I{sub CT} values, indicating that the I{sub CT} parameter is feasible for the evaluation of color variation. Meanwhile, by changing energy level and C/EAL thickness, the optimized device withmore » the widest color tuning range was based on N,N′-dicarbazolyl-3,5-benzene C/EAL, exhibiting the highest I{sub CT} value of 41.2%. Based on carrier quadratic hopping theory and exciton transfer model, two fitting I{sub CT} formulas derived from the highest occupied molecular orbital (HOMO) energy level and triplet energy level were simulated. Finally, a color tuning prediction (CTP) model was developed to deduce the I{sub CT} via C/EAL HOMO and triplet energy levels, and verified by the fabricated OLEDs with five different C/EALs. We believe that the CTP model assisted with I{sub CT} parameter will be helpful for fabricating high performance CT-OLEDs with a broad range of color tuning.« less

ESTIMATION OF GIARDIA CT VALUES AT HIGH PH FOR THE SURFACE WATER TREATMENT RULE

EPA Science Inventory

The U.S. Environmental Protection Agency currently recommends Ct (disinfectant concentration multiplied by the exposure time) values to achieve required levels of inactivation of Giardia lamblia cysts by different disinfectants including free chlorine. Current guidance covers ina...

Performance of highly sensitive cardiac troponin T assay to detect ischaemia at PET-CT in low-risk patients with acute coronary syndrome: a prospective observational study.

PubMed

Morawiec, Beata; Fournier, Stephane; Tapponnier, Maxime; Prior, John O; Monney, Pierre; Dunet, Vincent; Lauriers, Nathalie; Recordon, Frederique; Trana, Catalina; Iglesias, Juan-Fernando; Kawecki, Damian; Boulat, Olivier; Bardy, Daniel; Lamsidri, Sabine; Eeckhout, Eric; Hugli, Olivier; Muller, Olivier

2017-07-10

Highly sensitive troponin T (hs-TnT) assay has improved clinical decision-making for patients admitted with chest pain. However, this assay's performance in detecting myocardial ischaemia in a lowrisk population has been poorly documented. To assess hs-TnT assay's performance to detect myocardial ischaemia at positron emission tomography/CT (PET-CT) in low-risk patients admitted with chest pain. Patients admitted for chest pain with a nonconclusive ECG and negative standard cardiac troponin T results at admission and after 6 hours were prospectively enrolled. Their hs-TnT samples were at T0, T2 and T6. Physicians were blinded to hs-TnT results. All patients underwent a PET-CT at rest and during adenosine-induced stress. All patients with a positive PET-CT result underwent a coronary angiography. Forty-eight patients were included. Six had ischaemia at PET-CT. All of them had ≥1 significant stenosis at coronary angiography. Areas under the curve (95% CI) for predicting significant ischaemia at PET-CT using hs-TnT were 0.764 (0.515 to 1.000) at T0, 0.812(0.616 to 1.000) at T2 and 0.813(0.638 to 0.989) at T6. The receiver operating characteristicbased optimal cut-off value for hs-TnT at T0, T2 and T6 needed to exclude significant ischaemia at PET-CT was <4 ng/L. Using this value, sensitivity, specificity, positive and negative predictive values of hs-TnT to predict significant ischaemia were 83%/38%/16%/94% at T0, 100%/40%/19%/100% at T2 and 100%/43%/20%/100% at T6, respectively. Our findings suggest that in low-risk patients, using the hs-TnT assay with a cut-off value of 4 ng/L demonstrates excellent negative predictive value to exclude myocardial ischaemia detection at PET-CT, at the expense of weak specificity and positive predictive value. ClinicalTrials.gov Identifier: NCT01374607. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Simulating the nasal cycle with computational fluid dynamics

PubMed Central

Patel, Ruchin G.; Garcia, Guilherme J. M.; Frank-Ito, Dennis O.; Kimbell, Julia S.; Rhee, John S.

2015-01-01

Objectives (1) Develop a method to account for the confounding effect of the nasal cycle when comparing pre- and post-surgery objective measures of nasal patency. (2) Illustrate this method by reporting objective measures derived from computational fluid dynamics (CFD) models spanning the full range of mucosal engorgement associated with the nasal cycle in two subjects. Study Design Retrospective Setting Academic tertiary medical center. Subjects and Methods A cohort of 24 nasal airway obstruction patients was reviewed to select the two patients with the greatest reciprocal change in mucosal engorgement between pre- and post-surgery computed tomography (CT) scans. Three-dimensional anatomic models were created based on the pre- and post-operative CT scans. Nasal cycling models were also created by gradually changing the thickness of the inferior turbinate, middle turbinate, and septal swell body. CFD was used to simulate airflow and to calculate nasal resistance and average heat flux. Results Before accounting for the nasal cycle, Patient A appeared to have a paradoxical worsening nasal obstruction in the right cavity postoperatively. After accounting for the nasal cycle, Patient A had small improvements in objective measures postoperatively. The magnitude of the surgical effect also differed in Patient B after accounting for the nasal cycle. Conclusion By simulating the nasal cycle and comparing models in similar congestive states, surgical changes in nasal patency can be distinguished from physiological changes associated with the nasal cycle. This ability can lead to more precise comparisons of pre and post-surgery objective measures and potentially more accurate virtual surgery planning. PMID:25450411

Targeted overexpression of calcitonin in gonadotrophs of transgenic mice leads to chronic hypoprolactinemia.

PubMed

Yuan, Ren; Kulkarni, Trupti; Wei, Fu; Shah, Girish V

2005-01-14

It was previously shown that calcitonin-like pituitary peptide (pit-CT) is synthesized and secreted by gonadotrophs, and pit-CT inhibits PRL gene transcription and lactotroph cell proliferation. Present studies examined long-term consequences of pit-CT overexpression on the functioning of mouse anterior pituitary (AP) gland. Targeted overexpression of pit-CT in gonadotrophs of mouse pituitaries was achieved by generating mice overexpressing bovine luteinizing hormone (LH)-alpha subunit promoter-pit-CT cDNA transgene. Transgenic (pit-CT+) mice displayed chronic but selective overexpression of pit-CT in gonadotrophs. The mice also displayed a dramatic decline in PRL gene expression as assessed by PRL mRNA abundance, PRL immunohistochemistry (IHC) and serum PRL levels. LH secretion in pit-CT+ mice was also reduced, without any change in FSH secretion. Reproductive abnormalities such as prolonged estrous cycles, reduced pregnancy rate, delivery of smaller litters, increased neonatal mortality and deficient lactation were also observed. Administration of PRL during early pregnancy significantly increased the pregnancy rate and neonatal survival of newborns. These results demonstrate that overexpression of pit-CT leads to chronic hypoprolactinemia and reproductive dysfunction in female mice, and reinforces the possibility that gonadotroph-derived pit-CT is an important paracrine regulator of lactotroph function.

Computed tomography versus water-soluble contrast swallow in the detection of intrathoracic anastomotic leak complicating esophagogastrectomy (Ivor Lewis): a prospective study in 97 patients.

PubMed

Strauss, Christiane; Mal, Frederic; Perniceni, Thierry; Bouzar, Nadia; Lenoir, Stephane; Gayet, Brice; Palau, Robert

2010-04-01

Water-soluble contrast swallow (CS) is usually performed before refeeding for anastomosis assessment after esophagectomy with intrathoracic anastomosis but the sensitivity of CS is low. Another diagnostic approach is based on analysis of computed tomography (CT) scan with oral contrast and of CT mediastinal air images. We undertook to compare them prospectively. Ninety-seven patients with an esophageal carcinoma operated by intrathoracic anastomosis were included prospectively in a study based on a CT scan at postoperative day 3 (without oral and intravenous contrast) and CT scan and CS at day 7. CT scan analysis consisted of assessing contrast and air leakage. In case of doubt, an endoscopy was done. A diagnosis of anastomotic leak was made in 13 patients (13.4%), in 2 cases before day 7 and in 3 beyond day 7. At day 3, 94 CT scans were performed, but the diagnostic value was poor. In 95 patients with both CS and CT scan at day 7, CS disclosed a leak in 5 of 11, and CT scan was abnormal in 8 of 11. Leakage of contrast and/or presence of mediastinal gas had the best negative predictive value (95.8%). Endoscopy was done in 16 patients with only mediastinal gas at day 7 CT scan. It disclosed a normal anastomosis in 11, fibrin deposits in 4, and a leak in 1. In comparison with CS only, CT at day 7 improves the sensitivity and negative predictive value for diagnosing an anastomotic leak. In case of doubt endoscopy is advisable. This approach provides an accurate assessment of the anastomosis before refeeding.

3D echocardiographic analysis of aortic annulus for transcatheter aortic valve replacement using novel aortic valve quantification software: Comparison with computed tomography.

PubMed

Mediratta, Anuj; Addetia, Karima; Medvedofsky, Diego; Schneider, Robert J; Kruse, Eric; Shah, Atman P; Nathan, Sandeep; Paul, Jonathan D; Blair, John E; Ota, Takeyoshi; Balkhy, Husam H; Patel, Amit R; Mor-Avi, Victor; Lang, Roberto M

2017-05-01

With the increasing use of transcatheter aortic valve replacement (TAVR) in patients with aortic stenosis (AS), computed tomography (CT) remains the standard for annulus sizing. However, 3D transesophageal echocardiography (TEE) has been an alternative in patients with contraindications to CT. We sought to (1) test the feasibility, accuracy, and reproducibility of prototype 3DTEE analysis software (Philips) for aortic annular measurements and (2) compare the new approach to the existing echocardiographic techniques. We prospectively studied 52 patients who underwent gated contrast CT, procedural 3DTEE, and TAVR. 3DTEE images were analyzed using novel semi-automated software designed for 3D measurements of the aortic root, which uses multiplanar reconstruction, similar to CT analysis. Aortic annulus measurements included area, perimeter, and diameter calculations from these measurements. The results were compared to CT-derived values. Additionally, 3D echocardiographic measurements (3D planimetry and mitral valve analysis software adapted for the aortic valve) were also compared to the CT reference values. 3DTEE image quality was sufficient in 90% of patients for aortic annulus measurements using the new software, which were in good agreement with CT (r-values: .89-.91) and small (<4%) inter-modality nonsignificant biases. Repeated measurements showed <10% measurements variability. The new 3D analysis was the more accurate and reproducible of the existing echocardiographic techniques. Novel semi-automated 3DTEE analysis software can accurately measure aortic annulus in patients with severe AS undergoing TAVR, in better agreement with CT than the existing methodology. Accordingly, intra-procedural TEE could potentially replace CT in patients where CT carries significant risk. © 2017, Wiley Periodicals, Inc.

[Diagnostic values of bronchoscopy and multi-slice spiral CT for congenital dysplasia of the respiratory system in infants: a comparative study].

PubMed

Wang, Xing-Lu; Huang, Ying; Li, Qu-Bei; Dai, Ji-Hong

2013-09-01

To investigate and compare the diagnostic values of bronchoscopy and multi-slice spiral computed tomography (CT) for congenital dysplasia of the respiratory system in infants. Analysis was performed on the clinical data, bronchoscopic findings and multi-slice spiral CT findings of 319 infants (≤1 years old) who underwent bronchoscopy and/or multi-slice spiral CT and were diagnosed with congenital dysplasia of the respiratory system. A total of 476 cases of congenital dysplasia of the respiratory system were found in the 319 infants, including primary dysplasia of the respiratory system (392 cases) and compressive dysplasia of the respiratory system (84 cases). Of the 392 cases of primary dysplasia of the respiratory system, 225 (57.4%) were diagnosed by bronchoscopy versus 167 (42.6%) by multi-slice spiral CT. There were significant differences in etiological diagnosis between bronchoscopy and multi-slice spiral CT in infants with congenital dysplasia of the respiratory system (P<0.05). All 76 cases of primary dysplasia of the respiratory system caused by tracheobronchomalacia were diagnosed by bronchoscopy and all 17 cases of primary dysplasia of the respiratory system caused by lung tissue dysplasia were diagnosed by multi-slice spiral CT. Of the 84 cases of compressive dysplasia of the respiratory system, 74 cases were diagnosed by multi-slice spiral CT and only 10 cases were diagnosed by bronchoscopy. Compared with multi-slice spiral CT, bronchoscopy can detect primary dysplasia of the respiratory system more directly. Bronchoscopy is valuable in the confirmed diagnosis of tracheobronchomalacia. Multi-slice spiral CT has a higher diagnostic value for lung tissue dysplasia than bronchoscopy.

Comparative characteristics of quantitative indexes for 18F-FDG uptake and metabolic volume in sequentially obtained PET/MRI and PET/CT.

PubMed

Lee, Soo Jin; Paeng, Jin Chul; Goo, Jin Mo; Lee, Jeong Min; Cheon, Gi Jeong; Lee, Dong Soo; Chung, June-Key; Kang, Keon Wook

2017-04-01

The purpose of this study was to compare quantitative indexes for fluorine-18 fluorodeoxyglucose uptake and metabolic volume between PET/MRI and PET/CT. Sixty-six patients with solid tumors (32 with lung cancer and 34 with pancreatic cancer) who underwent sequential fluorine-18 fluorodeoxyglucose PET/MRI and PET/CT were retrospectively enrolled. On PET images, maximum and peak standardized uptake values (SUVmax and SUVpeak, respectively), and maximum tumor-to-liver ratio (TLRmax) were measured. Metabolic tumor volume (MTV) and total-lesion glycolysis (TLG) with margin thresholds of 50% SUVmax and SUV 2.5 (MTV50%, MTV2.5; TLG50%, TLG2.5, respectively) were compared between PET/MRI and PET/CT, with patients classified into two groups using imaging protocol (the PET/MRI-first and PET/CT-first groups). There were significant correlations of all tested indexes between PET/MRI and PET/CT (r=0.867-0.987, P<0.001). SUVmax and SUVpeak were lower on PET/MRI regardless of imaging protocol (P<0.001 in the PET/MRI-first group). In contrast, TLRmax exhibited reverse results between the PET/MRI-first and PET/CT-first groups. MTV50% and TLG values varied between PET/MRI and PET/CT, as well as between the PET/MRI-first and PET/CT-first groups. However, MTV2.5 was relatively robust against imaging protocol and modality. There are significant correlations of the quantitative indexes between PET/MRI and PET/CT. However, uptake indexes of SUVmax and SUVpeak are lower on PET/MRI than on PET/CT, and volumetric indexes of MTV50% and TLG values also exhibited significant differences. It may be suggested that TLRmax and MTV2.5 are relatively more appropriate indexes than others when PET/MRI and PET/CT are used interchangeably.

Feasibility of MR-only proton dose calculations for prostate cancer radiotherapy using a commercial pseudo-CT generation method

NASA Astrophysics Data System (ADS)

Maspero, Matteo; van den Berg, Cornelis A. T.; Landry, Guillaume; Belka, Claus; Parodi, Katia; Seevinck, Peter R.; Raaymakers, Bas W.; Kurz, Christopher

2017-12-01

A magnetic resonance (MR)-only radiotherapy workflow can reduce cost, radiation exposure and uncertainties introduced by CT-MRI registration. A crucial prerequisite is generating the so called pseudo-CT (pCT) images for accurate dose calculation and planning. Many pCT generation methods have been proposed in the scope of photon radiotherapy. This work aims at verifying for the first time whether a commercially available photon-oriented pCT generation method can be employed for accurate intensity-modulated proton therapy (IMPT) dose calculation. A retrospective study was conducted on ten prostate cancer patients. For pCT generation from MR images, a commercial solution for creating bulk-assigned pCTs, called MR for Attenuation Correction (MRCAT), was employed. The assigned pseudo-Hounsfield Unit (HU) values were adapted to yield an increased agreement to the reference CT in terms of proton range. Internal air cavities were copied from the CT to minimise inter-scan differences. CT- and MRCAT-based dose calculations for opposing beam IMPT plans were compared by gamma analysis and evaluation of clinically relevant target and organ at risk dose volume histogram (DVH) parameters. The proton range in beam’s eye view (BEV) was compared using single field uniform dose (SFUD) plans. On average, a (2%, 2 mm) gamma pass rate of 98.4% was obtained using a 10% dose threshold after adaptation of the pseudo-HU values. Mean differences between CT- and MRCAT-based dose in the DVH parameters were below 1 Gy (<1.5% ). The median proton range difference was 0.1 mm, with on average 96% of all BEV dose profiles showing a range agreement better than 3 mm. Results suggest that accurate MR-based proton dose calculation using an automatic commercial bulk-assignment pCT generation method, originally designed for photon radiotherapy, is feasible following adaptation of the assigned pseudo-HU values.

X-ray computed tomography comparison of individual and parallel assembled commercial lithium iron phosphate batteries at end of life after high rate cycling

NASA Astrophysics Data System (ADS)

Carter, Rachel; Huhman, Brett; Love, Corey T.; Zenyuk, Iryna V.

2018-03-01

X-ray computed tomography (X-ray CT) across multiple length scales is utilized for the first time to investigate the physical abuse of high C-rate pulsed discharge on cells wired individually and in parallel.. Manufactured lithium iron phosphate cells boasting high rate capability were pulse power tested in both wiring conditions with high discharge currents of 10C for a high number of cycles (up to 1200) until end of life (<80% of initial discharge capacity retained). The parallel assembly reached end of life more rapidly for reasons unknown prior to CT investigations. The investigation revealed evidence of overdischarge in the most degraded cell from the parallel assembly, compared to more traditional failure in the individual cell. The parallel-wired cell exhibited dissolution of copper from the anode current collector and subsequent deposition throughout the separator near the cathode of the cell. This overdischarge-induced copper deposition, notably impossible to confirm with other state of health (SOH) monitoring methods, is diagnosed using CT by rendering the interior current collector without harm or alteration to the active materials. Correlation of CT observations to the electrochemical pulse data from the parallel-wired cells reveals the risk of parallel wiring during high C-rate pulse discharge.

Quantitative myocardial blood flow imaging with integrated time-of-flight PET-MR.

PubMed

Kero, Tanja; Nordström, Jonny; Harms, Hendrik J; Sörensen, Jens; Ahlström, Håkan; Lubberink, Mark

2017-12-01

The use of integrated PET-MR offers new opportunities for comprehensive assessment of cardiac morphology and function. However, little is known on the quantitative accuracy of cardiac PET imaging with integrated time-of-flight PET-MR. The aim of the present work was to validate the GE Signa PET-MR scanner for quantitative cardiac PET perfusion imaging. Eleven patients (nine male; mean age 59 years; range 46-74 years) with known or suspected coronary artery disease underwent 15 O-water PET scans at rest and during adenosine-induced hyperaemia on a GE Discovery ST PET-CT and a GE Signa PET-MR scanner. PET-MR images were reconstructed using settings recommended by the manufacturer, including time-of-flight (TOF). Data were analysed semi-automatically using Cardiac VUer software, resulting in both parametric myocardial blood flow (MBF) images and segment-based MBF values. Correlation and agreement between PET-CT-based and PET-MR-based MBF values for all three coronary artery territories were assessed using regression analysis and intra-class correlation coefficients (ICC). In addition to the cardiac PET-MR reconstruction protocol as recommended by the manufacturer, comparisons were made using a PET-CT resolution-matched reconstruction protocol both without and with TOF to assess the effect of time-of-flight and reconstruction parameters on quantitative MBF values. Stress MBF data from one patient was excluded due to movement during the PET-CT scanning. Mean MBF values at rest and stress were (0.92 ± 0.12) and (2.74 ± 1.37) mL/g/min for PET-CT and (0.90 ± 0.23) and (2.65 ± 1.15) mL/g/min for PET-MR (p = 0.33 and p = 0.74). ICC between PET-CT-based and PET-MR-based regional MBF was 0.98. Image quality was improved with PET-MR as compared to PET-CT. ICC between PET-MR-based regional MBF with and without TOF and using different filter and reconstruction settings was 1.00. PET-MR-based MBF values correlated well with PET-CT-based MBF values and the parametric PET-MR images were excellent. TOF and reconstruction settings had little impact on MBF values.

Diagnostic value of computed tomography in dogs with chronic nasal disease.

PubMed

Saunders, Jimmy H; van Bree, Henri; Gielen, Ingrid; de Rooster, Hilde

2003-01-01

Computed tomographic (CT) studies of 80 dogs with chronic nasal disease (nasal neoplasia (n = 19), nasal aspergillosis (n = 46), nonspecific rhinitis (n = 11), and foreign body rhinitis (n = 4)) were reviewed retrospectively by two independent observers. Each observer filled out a custom-designed list to record his or her interpretation of the CT signs and selected a diagnosis. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for the diagnosis of each disease. The agreement between observers was evaluated. The CT signs corresponded to those previously described in the literature. CT had an accuracy greater than 90% for each observer in all disease processes. The sensitivity, specificity, PPV, and NPV were greater than 80% in all dogs with the exception of the PPV of foreign body rhinitis (80% for observer A and 44% for observer B). There was a substantial, to almost perfect, agreement between the two observers regarding the CT signs and diagnosis. This study indicates a high accuracy of CT for diagnosis of dogs with chronic nasal disease. The differentiation between nasal aspergillosis restricted to the nasal passages and foreign body rhinitis may be difficult when the foreign body is not visible.

Relationship between noise, dose, and pitch in cardiac multi-detector row CT.

PubMed

Primak, Andrew N; McCollough, Cynthia H; Bruesewitz, Michael R; Zhang, Jie; Fletcher, Joel G

2006-01-01

In spiral computed tomography (CT), dose is always inversely proportional to pitch. However, the relationship between noise and pitch (and hence noise and dose) depends on the scanner type (single vs multi-detector row) and reconstruction mode (cardiac vs noncardiac). In single detector row spiral CT, noise is independent of pitch. Conversely, in noncardiac multi-detector row CT, noise depends on pitch because the spiral interpolation algorithm makes use of redundant data from different detector rows to decrease noise for pitch values less than 1 (and increase noise for pitch values > 1). However, in cardiac spiral CT, redundant data cannot be used because such data averaging would degrade the temporal resolution. Therefore, the behavior of noise versus pitch returns to the single detector row paradigm, with noise being independent of pitch. Consequently, since faster rotation times require lower pitch values in cardiac multi-detector row CT, dose is increased without a commensurate decrease in noise. Thus, the use of faster rotation times will improve temporal resolution, not alter noise, and increase dose. For a particular application, the higher dose resulting from faster rotation speeds should be justified by the clinical benefits of the improved temporal resolution. RSNA, 2006

Tactile sensor is useful for estimating liver hardness and liver fibrosis compared with ultrasonography and computed tomography.

PubMed

Suzuki, Satoshi; Watanabe, Yohei; Yazawa, Takashi; Ishigame, Teruhide; Sassa, Motoki; Monma, Tomoyuki; Takawa, Tadashi; Kumamoto, Kensuke; Nakamura, Izumi; Ohoki, Shinji; Hatakeyama, Yuichi; Sakuma, Hiroshi; Ono, Toshiyuki; Omata, Sadao; Takenoshita, Seiichi

2014-01-01

We examined whether conventional ultrasonography (US) and computed tomography (CT) were useful to evaluate liver hardness and hepatic fibrosis by comparing the results with those obtained by a tactile sensor using rats with liver fibrosis. We used 44 Wistar rats in which liver fibrosis was induced by intraperitoneal administration of thioacetamide. The CT and US values of each liver were measured before laparotomy. After laparotomy, a tactile sensor was used to measure liver hardness. We prepared Azan stained sections of each excised liver specimen and calculated the degree of liver fibrosis (HFI: hepatic fibrosis index) by computed color image analysis. The stiffness values and HFI showed a positive correlation (r=0.690, p<0.001), as did the tactile values and HFI (r=0.709, p<0.001).In addition, the stiffness and tactile values correlated positively with each other (r=0.814, p<0.001). There was no correlation between the CT values and HFI, as well as no correlation between the US values and HFI. We confirmed that it was difficult to evaluate liver hardness and HFI by CT or US examination, and considered that, at present, a tactile sensor is useful method for evaluating HFI.

Diagnostic value of FDG-PET/(CT) in children with fever of unknown origin and unexplained fever during immune suppression.

PubMed

Blokhuis, Gijsbert J; Bleeker-Rovers, Chantal P; Diender, Marije G; Oyen, Wim J G; Draaisma, Jos M Th; de Geus-Oei, Lioe-Fee

2014-10-01

Fever of unknown origin (FUO) and unexplained fever during immune suppression in children are challenging medical problems. The aim of this study is to investigate the diagnostic value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) and FDG-PET combined with computed tomography (FDG-PET/CT) in children with FUO and in children with unexplained fever during immune suppression. All FDG-PET/(CT) scans performed in the Radboud university medical center for the evaluation of FUO or unexplained fever during immune suppression in the last 10 years were reviewed. Results were compared with the final clinical diagnosis. FDG-PET/(CT) scans were performed in 31 children with FUO. A final diagnosis was established in 16 cases (52 %). Of the total number of scans, 32 % were clinically helpful. The sensitivity and specificity of FDG-PET/CT in these patients was 80 % and 78 %, respectively. FDG-PET/(CT) scans were performed in 12 children with unexplained fever during immune suppression. A final diagnosis was established in nine patients (75 %). Of the total number of these scans, 58 % were clinically helpful. The sensitivity and specificity of FDG-PET/CT in children with unexplained fever during immune suppression was 78 % and 67 %, respectively. FDG-PET/CT appears a valuable imaging technique in the evaluation of children with FUO and in the diagnostic process of children with unexplained fever during immune suppression. Prospective studies of FDG-PET/CT as part of a structured diagnostic protocol are warranted to assess the additional diagnostic value.

Interobserver reliability of the young-burgess and tile classification systems for fractures of the pelvic ring.

PubMed

Koo, Henry; Leveridge, Mike; Thompson, Charles; Zdero, Rad; Bhandari, Mohit; Kreder, Hans J; Stephen, David; McKee, Michael D; Schemitsch, Emil H

2008-07-01

The purpose of this study was to measure interobserver reliability of 2 classification systems of pelvic ring fractures and to determine whether computed tomography (CT) improves reliability. The reliability of several radiographic findings was also tested. Thirty patients taken from a database at a Level I trauma facility were reviewed. For each patient, 3 radiographs (AP pelvis, inlet, and outlet) and CT scans were available. Six different reviewers (pelvic and acetabular specialist, orthopaedic traumatologist, or orthopaedic trainee) classified the injury according to Young-Burgess and Tile classification systems after reviewing plain radiographs and then after CT scans. The Kappa coefficient was used to determine interobserver reliability of these classification systems before and after CT scan. For plain radiographs, overall Kappa values for the Young-Burgess and Tile classification systems were 0.72 and 0.30, respectively. For CT scan and plain radiographs, the overall Kappa values for the Young-Burgess and Tile classification systems were 0.63 and 0.33, respectively. The pelvis/acetabular surgeons demonstrated the highest level of agreement using both classification systems. For individual questions, the addition of CT did significantly improve reviewer interpretation of fracture stability. The pre-CT and post-CT Kappa values for fracture stability were 0.59 and 0.93, respectively. The CT scan can improve the reliability of assessment of pelvic stability because of its ability to identify anatomical features of injury. The Young-Burgess system may be optimal for the learning surgeon. The Tile classification system is more beneficial for specialists in pelvic and acetabular surgery.

Correlation of X-ray computed tomography with quantitative nuclear magnetic resonance methods for pre-clinical measurement of adipose and lean tissues in living mice.

PubMed

Metzinger, Matthew N; Miramontes, Bernadette; Zhou, Peng; Liu, Yueying; Chapman, Sarah; Sun, Lucy; Sasser, Todd A; Duffield, Giles E; Stack, M Sharon; Leevy, W Matthew

2014-10-08

Numerous obesity studies have coupled murine models with non-invasive methods to quantify body composition in longitudinal experiments, including X-ray computed tomography (CT) or quantitative nuclear magnetic resonance (QMR). Both microCT and QMR have been separately validated with invasive techniques of adipose tissue quantification, like post-mortem fat extraction and measurement. Here we report a head-to-head study of both protocols using oil phantoms and mouse populations to determine the parameters that best align CT data with that from QMR. First, an in vitro analysis of oil/water mixtures was used to calibrate and assess the overall accuracy of microCT vs. QMR data. Next, experiments were conducted with two cohorts of living mice (either homogenous or heterogeneous by sex, age and genetic backgrounds) to assess the microCT imaging technique for adipose tissue segmentation and quantification relative to QMR. Adipose mass values were obtained from microCT data with three different resolutions, after which the data were analyzed with different filter and segmentation settings. Strong linearity was noted between the adipose mass values obtained with microCT and QMR, with optimal parameters and scan conditions reported herein. Lean tissue (muscle, internal organs) was also segmented and quantified using the microCT method relative to the analogous QMR values. Overall, the rigorous calibration and validation of the microCT method for murine body composition, relative to QMR, ensures its validity for segmentation, quantification and visualization of both adipose and lean tissues.

Assessing stapes piston position using computed tomography: a cadaveric study.

PubMed

Hahn, Yoav; Diaz, Rodney; Hartman, Jonathan; Bobinski, Matthew; Brodie, Hilary

2009-02-01

Temporal bone computed tomographic (CT) scanning in the postoperative stapedotomy patient is inaccurate in assessing stapes piston position within the vestibule. Poststapedotomy patients that have persistent vertigo may undergo CT scanning to assess the position of the stapes piston within the vestibule to rule out overly deep insertion. Vertigo is a recognized complication of the deep piston, and CT evaluation is often recommended. The accuracy of CT scan in this setting is unestablished. Stapedotomy was performed on 12 cadaver ears, and stainless steel McGee pistons were placed. The cadaver heads were then scanned using a fine-cut temporal bone protocol. Temporal bone dissection was performed with microscopic measurement of the piston depth in the vestibule. These values were compared with depth of intravestibular penetration measured on CT scan by 4 independent measurements. The intravestibular penetration as assessed by computed tomography was consistently greater than the value found on cadaveric anatomic dissection. The radiographic bias was greater when piston location within the vestibule was shallower. The axial CT scan measurement was 0.53 mm greater, on average, than the anatomic measurement. On average, the coronal CT measurement was 0.68 mm greater than the anatomic measurement. The degree of overestimation of penetration, however, was highly inconsistent. Standard temporal bone CT scan is neither an accurate nor precise examination of stapes piston depth within the vestibule. We found that CT measurement consistently overstated intravestibular piston depth. Computed tomography is not a useful study in the evaluation of piston depth for poststapedectomy vertigo and is of limited value in this setting.

Value of 18F-FDG PET/CT Combined With Tumor Markers in the Evaluation of Ascites.

PubMed

Han, Na; Sun, Xun; Qin, Chunxia; Hassan Bakari, Khamis; Wu, Zhijian; Zhang, Yongxue; Lan, Xiaoli

2018-05-01

The purpose of this study is to investigate the value of 18 F-FDG PET/CT combined with assessment of tumor markers in serum or ascites for the diagnosing and determining the prognosis of benign and malignant ascites. Patients with ascites of unknown cause who underwent evaluation with FDG PET/CT were included in this retrospective study. The maximum standardized uptake value (SUV max ) and levels of the tumor markers carbohydrate antigen-125 (CA-125) and carcinoembryonic antigen (CEA) in serum and ascites were recorded. The diagnostic values of FDG PET/CT, CEA and CA-125 levels in serum or ascites, and the combination of imaging plus tumor marker assessment were evaluated. Factors that were predictive of survival were also analyzed. A total of 177 patients were included. Malignant ascites was eventually diagnosed in 104 patients, and benign ascites was diagnosed in the remaining 73 patients. With the use of FDG PET/CT, 44 patients (42.3%) were found to have primary tumors. The sensitivity, specificity, and accuracy of FDG PET/CT were 92.3%, 83.6%, and 88.7%, respectively. CA-125 levels in serum and ascites showed much better sensitivity than did CEA levels, but they showed significantly lower specificity. If the combination of tumor markers and FDG PET/CT was analyzed, the sensitivity, specificity, and accuracy of tumor markers in serum were 96.6%, 78.1%, and 88.7%, and those of tumor markers in ascites were 97.7%, 80.0%, and 90.4%, respectively. Sex may be an important factor affecting survival time (hazard ratio, 0.471; p = 0.004), but age, CEA level, and FDG PET/CT findings could not predict survival. FDG PET/CT combined with assessment of tumor markers, especially CEA, increased the efficacy of diagnosis of ascites of unknown causes. Male sex conferred a poorer prognosis, whereas age, CEA level, and FDG uptake had no predictive significance in patients with malignant ascites.

WE-E-17A-05: Complementary Prognostic Value of CT and 18F-FDG PET Non-Small Cell Lung Cancer Tumor Heterogeneity Features Quantified Through Texture Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Desseroit, M; Cheze Le Rest, C; Tixier, F

2014-06-15

Purpose: Previous studies have shown that CT or 18F-FDG PET intratumor heterogeneity features computed using texture analysis may have prognostic value in Non-Small Cell Lung Cancer (NSCLC), but have been mostly investigated separately. The purpose of this study was to evaluate the potential added value with respect to prognosis regarding the combination of non-enhanced CT and 18F-FDG PET heterogeneity textural features on primary NSCLC tumors. Methods: One hundred patients with non-metastatic NSCLC (stage I–III), treated with surgery and/or (chemo)radiotherapy, that underwent staging 18F-FDG PET/CT images, were retrospectively included. Morphological tumor volumes were semi-automatically delineated on non-enhanced CT using 3D SlicerTM.more » Metabolically active tumor volumes (MATV) were automatically delineated on PET using the Fuzzy Locally Adaptive Bayesian (FLAB) method. Intratumoral tissue density and FDG uptake heterogeneities were quantified using texture parameters calculated from co-occurrence, difference, and run-length matrices. In addition to these textural features, first order histogram-derived metrics were computed on the whole morphological CT tumor volume, as well as on sub-volumes corresponding to fine, medium or coarse textures determined through various levels of LoG-filtering. Association with survival regarding all extracted features was assessed using Cox regression for both univariate and multivariate analysis. Results: Several PET and CT heterogeneity features were prognostic factors of overall survival in the univariate analysis. CT histogram-derived kurtosis and uniformity, as well as Low Grey-level High Run Emphasis (LGHRE), and PET local entropy were independent prognostic factors. Combined with stage and MATV, they led to a powerful prognostic model (p<0.0001), with median survival of 49 vs. 12.6 months and a hazard ratio of 3.5. Conclusion: Intratumoral heterogeneity quantified through textural features extracted from both CT and FDG PET images have complementary and independent prognostic value in NSCLC.« less

Dose reduction assessment in dynamic CT myocardial perfusion imaging in a porcine balloon-induced-ischemia model

NASA Astrophysics Data System (ADS)

Fahmi, Rachid; Eck, Brendan L.; Vembar, Mani; Bezerra, Hiram G.; Wilson, David L.

2014-03-01

We investigated the use of an advanced hybrid iterative reconstruction (IR) technique (iDose4, Philips Health- care) for low dose dynamic myocardial CT perfusion (CTP) imaging. A porcine model was created to mimic coronary stenosis through partial occlusion of the left anterior descending (LAD) artery with a balloon catheter. The severity of LAD occlusion was adjusted with FFR measurements. Dynamic CT images were acquired at end-systole (45% R-R) using a multi-detector CT (MDCT) scanner. Various corrections were applied to the acquired scans to reduce motion and imaging artifacts. Absolute myocardial blood flow (MBF) was computed with a deconvolution-based approach using singular value decomposition (SVD). We compared a high and a low dose radiation protocol corresponding to two different tube-voltage/tube-current combinations (80kV p/100mAs and 120kV p/150mAs). The corresponding radiation doses for these protocols are 7.8mSv and 34.3mSV , respectively. The images were reconstructed using conventional FBP and three noise-reduction strengths of the IR method, iDose. Flow contrast-to-noise ratio, CNRf, as obtained from MBF maps, was used to quantitatively evaluate the effect of reconstruction on contrast between normal and ischemic myocardial tissue. Preliminary results showed that the use of iDose to reconstruct low dose images provide better or comparable CNRf to that of high dose images reconstructed with FBP, suggesting significant dose savings. CNRf was improved with the three used levels of iDose compared to FBP for both protocols. When using the entire 4D dynamic sequence for MBF computation, a 77% dose reduction was achieved, while considering only half the scans (i.e., every other heart cycle) allowed even further dose reduction while maintaining relatively higher CNRf.

Some Further Evidence on the Rate of Return to Schooling and the Business Cycle.

ERIC Educational Resources Information Center

King, Randall H.

1980-01-01

The business cycle has a strong impact on calculated rates of return to schooling. Cross-sectional rates of return are positively related to the unemployment rate in the year the cross-section is taken. The sensitivity of the relationship was not found to be substantially different among the races. (CT)

Assessment of an organ-based tube current modulation in thoracic computed tomography.

PubMed

Matsubara, Kosuke; Sugai, Mai; Toyoda, Asami; Koshida, Haruka; Sakuta, Keita; Takata, Tadanori; Koshida, Kichiro; Iida, Hiroji; Matsui, Osamu

2012-03-08

Recently, specific computed tomography (CT) scanners have been equipped with organ-based tube current modulation (TCM) technology. It is possible that organ-based TCM will replace the conventional dose-reduction technique of reducing the effective milliampere-second. The aim of this study was to determine if organ-based TCM could reduce radiation exposure to the breasts without compromising the image uniformity and beam hardening effect in thoracic CT examinations. Breast and skin radiation doses and the absorbed radiation dose distribution within a single section were measured with an anthropomorphic phantom and radiophotoluminescent glass dosimeters using four approaches to thoracic CT (reference, organ-based TCM, copper shielding, and the combination of the above two techniques, hereafter referred to as the combination technique). The CT value and noise level were measured using the same calibration phantom. Organ-based TCM and copper shielding reduced radiation doses to the breast by 23.7% and 21.8%, respectively. However, the CT value increased, especially in the anterior region, using copper shielding. In contrast, the CT value and noise level barely increased using organ-based TCM. The combination technique reduced the radiation dose to the breast by 38.2%, but greatly increased the absorbed radiation dose from the central to the posterior regions. Moreover, the CT value increased in the anterior region and the noise level increased by more than 10% in the entire region. Therefore, organ-based TCM can reduce radiation doses to breasts with only small increases in noise levels, making it preferable for specific groups of patients, such as children and young women.

Diagnostic and prognostic value of 18F-FDG PET/CT in recurrent germinal tumor carcinoma.

PubMed

Alongi, Pierpaolo; Evangelista, Laura; Caobelli, Federico; Spallino, Marianna; Gianolli, Luigi; Midiri, Massimo; Picchio, Maria

2018-01-01

The aim of this bicentric retrospective study was to assess the diagnostic performance, the prognostic value, the incremental prognostic value and the impact on therapeutic management of 18 F-FDG PET/CT in patients with suspected recurrent germinal cell testicular carcinoma (GCT). From the databases of two centers including 31,500 18 F-FDG PET/CT oncological studies, 114 patients affected by GCT were evaluated in a retrospective study. All 114 patients underwent 18 F-FDG PET/CT for suspected recurrent disease. Diagnostic performance of visually interpreted 18 F-FDG PET/CT and potential impact on the treatment decision were assessed using histology (17 patients), other diagnostic imaging modalities (i.e., contrast enhanced CT in 89 patients and MRI in 15) and clinical follow-up (114 patients) as reference. Progression-free survival (PFS) and overall survival (OS) rates were computed by means of Kaplan-Meier survival analysis. The progression rate (Hazard Ratio-HR) was determined using univariate Cox regression analysis by considering various clinical variables. Recurrent GCT was confirmed in 47 of 52 patients with pathological 18 F-FDG PET/CT findings, by means of histology in 18 patients and by other diagnostic imaging modalities/follow-up in 29. Sensitivity, specificity, accuracy, positive and negative likelihood ratio (LR+ and LR-, respectively), pre-test Odds-ratio and post-test Odds-ratio of 18 FDG PET/CT were 86.8%, 90.2%, 88.4%, 8.85, 0.14, 0.85, 8.85, respectively. 18 F-FDG PET/CT impacted significantly on therapeutic management in 26/114 (23%) cases (from palliative to curative in 12 patients, from "wait and watch" to new chemotherapy in six patients and the "wait-and-watch" approach in eight patients with unremarkable findings). At 2 and 5-year follow-up, PFS was significantly longer in patients with a negative than a pathological 18 F-FDG PET/CT scan (98% and 95% vs 48% and 38%, respectively; p = 0.02). An unremarkable scan was associated also with a longer OS (98% after 2 years and 95% after 5 years, p = 0.02). At univariate Cox regression analysis, a pathological 18 F-FDG PET/CT scan was associated with an increased risk of disease progression (HR = 24.3, CI 95% 14.1-40.6; p = 0.03) and lower OS (HR = 17.3 CI 95% 4,9-77; p < 0.001). Its prognostic value was confirmed also if tested against advanced disease at diagnosis and rising Human Chorionic Gonadotropin Beta (HCGB) or Alpha-Fetoprotein (AFP) (HR = 7.3 for STAGE III-PET+, p = 0.03; HR = 14.3 elevated HCGB-PET+, p = 0.02; HR 10.7 elevated AFP-PET+, p = 0.01) At multivariate analysis, only a pathological 18 F-FDG PET/CT scan and advanced disease in terms of TNM staging were predictors of disease progression and OS. 18 F-FDG PET/CT showed incremental value over other variables both in predicting PFS (chi-square from 24 to 40, p < 0.001) and OS (chi-square from 32 to 38, p = 0.003). 18 F-FDG PET/CT has a very good diagnostic performance in patients with suspected recurrent GCT and has an important prognostic value in assessing the rate of PFS and OS. Furthermore, 18 F-FDG PET/CT impacted the therapeutic regimen in 23% of patients, thus providing a significant impact in the restaging process.

Direct comparison of Xpert MTB/RIF assay with liquid and solid mycobacterial culture for quantification of early bactericidal activity.

PubMed

Kayigire, Xavier A; Friedrich, Sven O; Venter, Amour; Dawson, Rodney; Gillespie, Stephen H; Boeree, Martin J; Heinrich, Norbert; Hoelscher, Michael; Diacon, Andreas H

2013-06-01

The early bactericidal activity of antituberculosis agents is usually determined by measuring the reduction of the sputum mycobacterial load over time on solid agar medium or in liquid culture. This study investigated the value of a quantitative PCR assay for early bactericidal activity determination. Groups of 15 patients were treated with 6 different antituberculosis agents or regimens. Patients collected sputum for 16 h overnight at baseline and at days 7 and 14 after treatment initiation. We determined the sputum bacterial load by CFU counting (log CFU/ml sputum, reported as mean ± standard deviation [SD]), time to culture positivity (TTP, in hours [mean ± SD]) in liquid culture, and Xpert MTB/RIF cycle thresholds (C(T), n [mean ± SD]). The ability to discriminate treatment effects between groups was analyzed with one-way analysis of variance (ANOVA). All measurements showed a decrease in bacterial load from mean baseline (log CFU, 5.72 ± 1.00; TTP, 116.0 ± 47.6; C(T), 19.3 ± 3.88) to day 7 (log CFU, -0.26 ± 1.23, P = 0.2112; TTP, 35.5 ± 59.3, P = 0.0002; C(T), 0.55 ± 3.07, P = 0.6030) and day 14 (log CFU, -0.55 ± 1.24, P = 0.0006; TTP, 54.8 ± 86.8, P < 0.0001; C(T), 2.06 ± 4.37, P = 0.0020). The best discrimination between group effects was found with TTP at day 7 and day 14 (F = 9.012, P < 0.0001, and F = 11.580, P < 0.0001), followed by log CFU (F = 4.135, P = 0.0024, and F = 7.277, P < 0.0001). C(T) was not significantly discriminative (F = 1.995, P = 0.091, and F = 1.203, P = 0.316, respectively). Culture-based methods are superior to PCR for the quantification of early antituberculosis treatment effects in sputum.

Cognitive Reserve in Dementia: Implications for Cognitive Training

PubMed Central

Mondini, Sara; Madella, Ileana; Zangrossi, Andrea; Bigolin, Angela; Tomasi, Claudia; Michieletto, Marta; Villani, Daniele; Di Giovanni, Giuseppina; Mapelli, Daniela

2016-01-01

Cognitive reserve (CR) is a potential mechanism to cope with brain damage. The aim of this study was to evaluate the effect of CR on a cognitive training (CT) in a group of patients with dementia. Eighty six participants with mild to moderate dementia were identified by their level of CR quantified by the CR Index questionnaire (CRIq) and underwent a cycle of CT. A global measure of cognition mini mental state examination (MMSE) was obtained before (T0) and after (T1) the training. Multiple linear regression analyses highlighted CR as a significant factor able to predict changes in cognitive performance after the CT. In particular, patients with lower CR benefited from a CT program more than those with high CR. These data show that CR can modulate the outcome of a CT program and that it should be considered as a predictive factor of neuropsychological rehabilitation training efficacy in people with dementia. PMID:27199734

CT findings of acute cholecystitis and its complications.

PubMed

Shakespear, Jonathan S; Shaaban, Akram M; Rezvani, Maryam

2010-06-01

The purpose of this article is to describe and illustrate the CT findings of acute cholecystitis and its complications. CT findings suggesting acute cholecystitis should be interpreted with caution and should probably serve as justification for further investigation with abdominal ultrasound. CT has a relatively high negative predictive value, and acute cholecystitis is unlikely in the setting of a negative CT. Complications of acute cholecystitis have a characteristic CT appearance and include necrosis, perforation, abscess formation, intraluminal hemorrhage, and wall emphysema.

50. VIEW LOOKING SOUTHEAST AT A MOTORGENERATOR SET LOCATED UNDER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

50. VIEW LOOKING SOUTHEAST AT A MOTOR-GENERATOR SET LOCATED UNDER CONTROL ROOM. THREE 450 kva., 2500 VOLT, 60 CYCLE MOTOR-GENERATOR UNITS PROVIDED POWER FOR THE RAILROAD SIGNAL SYSTEM. 25 CYCLE POWER WAS PROVIDED TO THE MOTOR (LEFT BACKGROUND). THE MOTOR TURNED THE GENERATOR (CENTER FOREGROUND) WHICH PRODUCED 60 CYCLE POWER TO OPERATE LIGHTS AND SIGNALING DEVICES. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

Interobserver agreement of interim and end-of-treatment 18F-FDG PET/CT in diffuse large B-cell lymphoma (DLBCL): impact on clinical practice and trials.

PubMed

Burggraaff, Coreline N; Cornelisse, Alexander C; Hoekstra, Otto S; Lugtenburg, Pieternella J; de Keizer, Bart; Arens, Anne I J; Celik, Filiz; Huijbregts, Julia E; De Vet, Henrica C W; Zijlstra, Josee M

2018-05-04

We aimed to assess the interobserver agreement of Interim PET (I-PET) and End-of-Treatment PET (EoT-PET) using the Deauville 5-point scale (DS) in first-line DLBCL patients. Methods: I-PET and EoT-PET scans of DLBCL patients were performed in the HOVON84 study (2007-2012), an international multicenter randomized controlled trial. Patients received R-CHOP14 and were randomized to receive rituximab intensification in the first 4 cycles or not. I-PET was made after 4 cycles (for observational purposes), and EoT-PET scan after 6 or 8 cycles. Two independent central reviewers retrospectively scored all scans according to the DS-system, blinded to clinical outcomes. Results were dichotomised as 'negative' (DS: 1-3) or 'positive' (DS: 4-5). Besides percentage overall agreement we calculated agreement for positive and negative scores, expressed as positive agreement (PA) and negative agreement (NA), respectively. Results: 465 I-PET and 457 EoT-PET scans were centrally reviewed; baseline 18 F-FDG PET(/CT) was available in 75-77%, and CT in the remaining cases. Percentage overall agreement for I-PET and EoT-PET were 87.7% and 91.7% ( P =0.049), with NA of 92.0% and 95.0% ( P =0.091), and PA of 73.7% and 76.3% ( P =0.656), respectively. Conclusion: Interobserver agreement using DS in DLBCL patients in I-PET and EoT-PET yields high overall and negative agreement. The lower positive agreement suggests that EoT-PET/CT treatment evaluation in daily practice and I-PET adapted trials may benefit from dual reads and central review, respectively. Copyright © 2018 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

The Use of Automated SNOMED CT Clinical Coding in Clinical Decision Support Systems for Preventive Care.

PubMed

Al-Hablani, Bader

2017-01-01

The objective of this study is to discuss and analyze the use of automated SNOMED CT clinical coding in clinical decision support systems (CDSSs) for preventive care. The central question that this study seeks to answer is whether the utilization of SNOMED CT in CDSSs can improve preventive care. PubMed, Google Scholar, and Cochrane Library were searched for articles published in English between 2001 and 2012 on SNOMED CT, CDSS, and preventive care. Outcome measures were the sensitivity or specificity of SNOMED CT coded data and the positive predictive value or negative predictive value of SNOMED CT coded data. Additionally, we documented the publication year, research question, study design, results, and conclusions of these studies. The reviewed studies suggested that SNOMED CT successfully represents clinical terms and negated clinical terms. The use of SNOMED CT in CDSS can be considered to provide an answer to the problem of medical errors as well as for preventive care in general. Enhancement of the modifiers and synonyms found in SNOMED CT will be necessary to improve the expected outcome of the integration of SNOMED CT with CDSS. Moreover, the application of the tree-augmented naïve (TAN) Bayesian network method can be considered the best technique to search SNOMED CT data and, consequently, to help improve preventive health services.

The Use of Automated SNOMED CT Clinical Coding in Clinical Decision Support Systems for Preventive Care

PubMed Central

Al-Hablani, Bader

2017-01-01

Objective The objective of this study is to discuss and analyze the use of automated SNOMED CT clinical coding in clinical decision support systems (CDSSs) for preventive care. The central question that this study seeks to answer is whether the utilization of SNOMED CT in CDSSs can improve preventive care. Method PubMed, Google Scholar, and Cochrane Library were searched for articles published in English between 2001 and 2012 on SNOMED CT, CDSS, and preventive care. Outcome Measures Outcome measures were the sensitivity or specificity of SNOMED CT coded data and the positive predictive value or negative predictive value of SNOMED CT coded data. Additionally, we documented the publication year, research question, study design, results, and conclusions of these studies. Results The reviewed studies suggested that SNOMED CT successfully represents clinical terms and negated clinical terms. Conclusion The use of SNOMED CT in CDSS can be considered to provide an answer to the problem of medical errors as well as for preventive care in general. Enhancement of the modifiers and synonyms found in SNOMED CT will be necessary to improve the expected outcome of the integration of SNOMED CT with CDSS. Moreover, the application of the tree-augmented naïve (TAN) Bayesian network method can be considered the best technique to search SNOMED CT data and, consequently, to help improve preventive health services. PMID:28566995

Accuracy of limited four-slice CT-scan in diagnosis of chronic rhinosinusitis.

PubMed

Zojaji, R; Nekooei, S; Naghibi, S; Mazloum Farsi Baf, M; Jalilian, R; Masoomi, M

2015-12-01

Chronic rhinosinusitis (CRS) is a common chronic health condition worldwide. Standard CT-scan is the method of choice for diagnosis of CRS but its high price and considerable radiation exposure have limited its application. The main goal of this study was to evaluate the accuracy of limited four-slice coronal CT-scan in the diagnosis of CRS. This cross-sectional study was conducted on 46 patients with CRS, for one year, based on American Society of Head and Neck Surgery criteria. All patients received the preoperative standard and four-slice CT-scans, after which endoscopic sinus surgery was performed. Findings of four-slice CT-scans were compared with those of conventional CT-scan and the sensitivity and specificity of four-slice CT-scan and its agreement with conventional CT-scan was calculated. In this study, 46 patients including 32 males (69.6%) and 14 females (30.46%) with a mean age of 33 and standard deviation of 9 years, were evaluated. Sensitivity and specificity of four-slice CT-scan were 97.5% and 100%, respectively. Also, positive predictive value (PPV) and negative predictive value (NPV) of four-slice CT was 100% and 85.71%, respectively. There was a strong agreement between four-slice CT and conventional CT findings. Considering the high sensitivity and specificity of four-slice CT-scan and strong agreement with conventional CT-scan in the diagnosis of CRS and the lower radiation exposure and cost, application of this method is suggested for both diagnosis and treatment follow-up in CRS. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Reproducibility of image quality for moving objects using respiratory-gated computed tomography: a study using a phantom model

PubMed Central

Fukumitsu, Nobuyoshi; Ishida, Masaya; Terunuma, Toshiyuki; Mizumoto, Masashi; Hashimoto, Takayuki; Moritake, Takashi; Okumura, Toshiyuki; Sakae, Takeji; Tsuboi, Koji; Sakurai, Hideyuki

2012-01-01

To investigate the reproducibility of computed tomography (CT) imaging quality in respiratory-gated radiation treatment planning is essential in radiotherapy of movable tumors. Seven series of regular and six series of irregular respiratory motions were performed using a thorax dynamic phantom. For the regular respiratory motions, the respiratory cycle was changed from 2.5 to 4 s and the amplitude was changed from 4 to 10 mm. For the irregular respiratory motions, a cycle of 2.5 to 4 or an amplitude of 4 to 10 mm was added to the base data (i.e. 3.5-s cycle, 6-mm amplitude) every three cycles. Images of the object were acquired six times using respiratory-gated data acquisition. The volume of the object was calculated and the reproducibility of the volume was decided based on the variety. The registered image of the object was added and the reproducibility of the shape was decided based on the degree of overlap of objects. The variety in the volumes and shapes differed significantly as the respiratory cycle changed according to regular respiratory motions. In irregular respiratory motion, shape reproducibility was further inferior, and the percentage of overlap among the six images was 35.26% in the 2.5- and 3.5-s cycle mixed group. Amplitude changes did not produce significant differences in the variety of the volumes and shapes. Respiratory cycle changes reduced the reproducibility of the image quality in respiratory-gated CT. PMID:22966173

Diagnosing Early Ischemic Changes with the Latest-Generation Flat Detector CT: A Comparative Study with Multidetector CT.

PubMed

Maier, I L; Leyhe, J R; Tsogkas, I; Behme, D; Schregel, K; Knauth, M; Schnieder, M; Liman, J; Psychogios, M-N

2018-05-01

One-stop management of mechanical thrombectomy-eligible patients with large-vessel occlusion represents an innovative approach in acute stroke treatment. This approach reduces door-to-reperfusion times by omitting multidetector CT, using flat detector CT as pre-mechanical thrombectomy imaging. The purpose of this study was to compare the diagnostic performance of the latest-generation flat detector CT with multidetector CT. Prospectively derived data from patients with ischemic stroke with large-vessel occlusion and mechanical thrombectomy were analyzed in this monocentric study. All included patients underwent multidetector CT before referral to our comprehensive stroke center and flat detector CT in the angiography suite before mechanical thrombectomy. Diagnosis of early ischemic signs, quantified by the ASPECTS, was compared between modalities using cross tables, the Pearson correlation, and Bland-Altman plots. The predictive value of multidetector CT- and flat detector CT-derived ASPECTS for functional outcome was investigated using area under the receiver operating characteristic curve analysis. Of 25 patients, 24 (96%) had flat detector CT with sufficient diagnostic quality. Median multidetector CT and flat detector CT ASPECTSs were 7 (interquartile range, 5.5-9 and 4.25-8, respectively) with a mean period of 143.6 ± 49.5 minutes between both modalities. The overall sensitivity was 85.1% and specificity was 83.1% for flat detector CT ASPECTS compared with multidetector CT ASPECTS as the reference technique. Multidetector CT and flat detector CT ASPECTS were strongly correlated ( r = 0.849, P < .001) and moderately predicted functional outcome (area under the receiver operating characteristic curve, 0.738; P = .007 and .715; P = .069, respectively). Determination of ASPECTS on flat detector CT is feasible, showing no significant difference compared with multidetector CT ASPECTS and a similar predictive value for functional outcome. Our findings support the use of flat detector CT for emergency stroke imaging before mechanical thrombectomy to reduce door-to-groin time. © 2018 by American Journal of Neuroradiology.

A dual model HU conversion from MRI intensity values within and outside of bone segment for MRI-based radiotherapy treatment planning of prostate cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korhonen, Juha, E-mail: juha.p.korhonen@hus.fi; Department of Oncology, Helsinki University Central Hospital, POB-180, 00029 HUS; Kapanen, Mika

2014-01-15

Purpose: The lack of electron density information in magnetic resonance images (MRI) poses a major challenge for MRI-based radiotherapy treatment planning (RTP). In this study the authors convert MRI intensity values into Hounsfield units (HUs) in the male pelvis and thus enable accurate MRI-based RTP for prostate cancer patients with varying tissue anatomy and body fat contents. Methods: T{sub 1}/T{sub 2}*-weighted MRI intensity values and standard computed tomography (CT) image HUs in the male pelvis were analyzed using image data of 10 prostate cancer patients. The collected data were utilized to generate a dual model HU conversion technique from MRImore » intensity values of the single image set separately within and outside of contoured pelvic bones. Within the bone segment local MRI intensity values were converted to HUs by applying a second-order polynomial model. This model was tuned for each patient by two patient-specific adjustments: MR signal normalization to correct shifts in absolute intensity level and application of a cutoff value to accurately represent low density bony tissue HUs. For soft tissues, such as fat and muscle, located outside of the bone contours, a threshold-based segmentation method without requirements for any patient-specific adjustments was introduced to convert MRI intensity values into HUs. The dual model HU conversion technique was implemented by constructing pseudo-CT images for 10 other prostate cancer patients. The feasibility of these images for RTP was evaluated by comparing HUs in the generated pseudo-CT images with those in standard CT images, and by determining deviations in MRI-based dose distributions compared to those in CT images with 7-field intensity modulated radiation therapy (IMRT) with the anisotropic analytical algorithm and 360° volumetric-modulated arc therapy (VMAT) with the Voxel Monte Carlo algorithm. Results: The average HU differences between the constructed pseudo-CT images and standard CT images of each test patient ranged from −2 to 5 HUs and from 22 to 78 HUs in soft and bony tissues, respectively. The average local absolute value differences were 11 HUs in soft tissues and 99 HUs in bones. The planning target volume doses (volumes 95%, 50%, 5%) in the pseudo-CT images were within 0.8% compared to those in CT images in all of the 20 treatment plans. The average deviation was 0.3%. With all the test patients over 94% (IMRT) and 92% (VMAT) of dose points within body (lower than 10% of maximum dose suppressed) passed the 1 mm and 1% 2D gamma index criterion. The statistical tests (t- and F-tests) showed significantly improved (p ≤ 0.05) HU and dose calculation accuracies with the soft tissue conversion method instead of homogeneous representation of these tissues in MRI-based RTP images. Conclusions: This study indicates that it is possible to construct high quality pseudo-CT images by converting the intensity values of a single MRI series into HUs in the male pelvis, and to use these images for accurate MRI-based prostate RTP dose calculations.« less

Experimental Evaluation of a Deformable Registration Algorithm for Motion Correction in PET-CT Guided Biopsy.

PubMed

Khare, Rahul; Sala, Guillaume; Kinahan, Paul; Esposito, Giuseppe; Banovac, Filip; Cleary, Kevin; Enquobahrie, Andinet

2013-01-01

Positron emission tomography computed tomography (PET-CT) images are increasingly being used for guidance during percutaneous biopsy. However, due to the physics of image acquisition, PET-CT images are susceptible to problems due to respiratory and cardiac motion, leading to inaccurate tumor localization, shape distortion, and attenuation correction. To address these problems, we present a method for motion correction that relies on respiratory gated CT images aligned using a deformable registration algorithm. In this work, we use two deformable registration algorithms and two optimization approaches for registering the CT images obtained over the respiratory cycle. The two algorithms are the BSpline and the symmetric forces Demons registration. In the first optmization approach, CT images at each time point are registered to a single reference time point. In the second approach, deformation maps are obtained to align each CT time point with its adjacent time point. These deformations are then composed to find the deformation with respect to a reference time point. We evaluate these two algorithms and optimization approaches using respiratory gated CT images obtained from 7 patients. Our results show that overall the BSpline registration algorithm with the reference optimization approach gives the best results.

Comparison of Tissue Density in Hounsfield Units in Computed Tomography and Cone Beam Computed Tomography.

PubMed

Varshowsaz, Masoud; Goorang, Sepideh; Ehsani, Sara; Azizi, Zeynab; Rahimian, Sepideh

2016-03-01

Bone quality and quantity assessment is one of the most important steps in implant treatment planning. Different methods such as computed tomography (CT) and recently suggested cone beam computed tomography (CBCT) with lower radiation dose and less time and cost are used for bone density assessment. This in vitro study aimed to compare the tissue density values in Hounsfield units (HUs) in CBCT and CT scans of different tissue phantoms with two different thicknesses, two different image acquisition settings and in three locations in the phantoms. Four different tissue phantoms namely hard tissue, soft tissue, air and water were scanned by three different CBCT and a CT system in two thicknesses (full and half) and two image acquisition settings (high and low kVp and mA). The images were analyzed at three sites (middle, periphery and intermediate) using eFilm software. The difference in density values was analyzed by ANOVA and correction coefficient test (P<0.05). There was a significant difference between density values in CBCT and CT scans in most situations, and CBCT values were not similar to CT values in any of the phantoms in different thicknesses and acquisition parameters or the three different sites. The correction coefficients confirmed the results. CBCT is not reliable for tissue density assessment. The results were not affected by changes in thickness, acquisition parameters or locations.

A prospective gating method to acquire a diverse set of free-breathing CT images for model-based 4DCT

NASA Astrophysics Data System (ADS)

O'Connell, D.; Ruan, D.; Thomas, D. H.; Dou, T. H.; Lewis, J. H.; Santhanam, A.; Lee, P.; Low, D. A.

2018-02-01

Breathing motion modeling requires observation of tissues at sufficiently distinct respiratory states for proper 4D characterization. This work proposes a method to improve sampling of the breathing cycle with limited imaging dose. We designed and tested a prospective free-breathing acquisition protocol with a simulation using datasets from five patients imaged with a model-based 4DCT technique. Each dataset contained 25 free-breathing fast helical CT scans with simultaneous breathing surrogate measurements. Tissue displacements were measured using deformable image registration. A correspondence model related tissue displacement to the surrogate. Model residual was computed by comparing predicted displacements to image registration results. To determine a stopping criteria for the prospective protocol, i.e. when the breathing cycle had been sufficiently sampled, subsets of N scans where 5  ⩽  N  ⩽  9 were used to fit reduced models for each patient. A previously published metric was employed to describe the phase coverage, or ‘spread’, of the respiratory trajectories of each subset. Minimum phase coverage necessary to achieve mean model residual within 0.5 mm of the full 25-scan model was determined and used as the stopping criteria. Using the patient breathing traces, a prospective acquisition protocol was simulated. In all patients, phase coverage greater than the threshold necessary for model accuracy within 0.5 mm of the 25 scan model was achieved in six or fewer scans. The prospectively selected respiratory trajectories ranked in the (97.5  ±  4.2)th percentile among subsets of the originally sampled scans on average. Simulation results suggest that the proposed prospective method provides an effective means to sample the breathing cycle with limited free-breathing scans. One application of the method is to reduce the imaging dose of a previously published model-based 4DCT protocol to 25% of its original value while achieving mean model residual within 0.5 mm.

Predictive and prognostic value of 18F-DOPA PET/CT in patients affected by recurrent medullary carcinoma of the thyroid.

PubMed

Caobelli, Federico; Chiaravalloti, Agostino; Evangelista, Laura; Saladini, Giorgio; Schillaci, Orazio; Vadrucci, Manuela; Scalorbi, Federica; Donner, Davide; Alongi, Pierpaolo

2018-01-01

Medullary thyroid carcinoma (MTC) is a malignancy accounting for about 5-8% of thyroid cancers. Serum calcitonin and carcinoembryonic antigen (CEA) levels are widely used to monitor disease progression. However, prognostic factors able to predict outcomes are highly desirable. We, therefore, aimed to assess the prognostic role of 18 F-DOPA PET/CT in patients with recurrent MTC. 60 patients (mean age 64 ± 13 years, range 44-82) with recurrent MTC were eligible from a multicenter database. All patients underwent a restaging 18 F-DOPA PET/CT, performed at least 6 months after surgery. CEA/calcitonin levels, local recurrences, nodal involvement and metastases at PET/CT were recorded. SUVmax, SUVmean (also normalized to mediastinal uptake) and metabolic tumor volume were automatically calculated for each lesion, by placing a volume of interest around the lesion with 40% of peak activity as threshold for the automatic contouring. The patients were clinically and radiologically followed up for 21 ± 11 months. Rate of progression-free survival (PFS), disease-specific survival (DSS) and incremental prognostic value of 18 F-DOPA PET/CT over conventional imaging modalities were assessed by Kaplan-Meier curves and Log-Rank test. Cox regression univariate and multivariate analyses were performed for assessing predictors of prognosis. 18 F-DOPA PET/CT showed abnormal findings in 27 patients (45%) and resulted unremarkable in 33 (55%). PFS was significantly longer in patients with an unremarkable PET/CT scan (p = 0.018). Similarly, an unremarkable PET/CT study was associated with a significantly longer DSS (p = 0.04). 18 F-DOPA PET/CT added prognostic value over other imaging modalities both for PFS and for DSS (p < 0.001 and p = 0.012, respectively). Neither semiquantitative PET parameters nor clinical or laboratory data were predictive of a worse PFS and DSS in patients with recurrent MTC. 18 F-DOPA PET/CT scan has an important prognostic value in predicting disease progression and mortality rate.

Performance evaluation of G8, a high sensitivity benchtop preclinical PET/CT tomograph.

PubMed

Gu, Zheng; Taschereau, Richard; Vu, Nam; Prout, David L; Silverman, Robert W; Lee, Jason; Chatziioannou, Arion F

2018-06-14

G8 is a bench top integrated PET/CT scanner dedicated to high sensitivity and high resolution imaging of mice. This work characterizes its National Electrical Manufacturers Association (NEMA) NU4-2008 performance where applicable and also provides an assessment of the basic imaging performance of the CT subsystem. Methods: The PET subsystem in G8 consists of four flat-panel type detectors arranged in a box like geometry. Each panel consists of two modules of a 26 × 26 pixelated bismuth germanate (BGO) scintillator array with individual crystals measuring 1.75 × 1.75 × 7.2 mm. The crystal arrays are coupled to multichannel photomultiplier tubes via a tapered, pixelated glass lightguide. A cone-beam CT consisting of a micro focus X-ray source and a Complementary Metal Oxide Semiconductor (CMOS) detector provides anatomical information. Sensitivity, spatial resolution, energy resolution, scatter fraction, count-rate performance and the capability of phantom and mouse imaging were evaluated for the PET subsystem. Noise, dose level, contrast and resolution were evaluated for the CT subsystem. Results: With an energy window of 350-650 keV, the peak sensitivity was measured to be 9.0% near the center of the field of view (CFOV). The crystal energy resolution ranged from 15.0% to 69.6% full width at half maximum (FWHM), with a mean of 19.3 ± 3.7%. The average detector intrinsic spatial resolution was 1.30 mm and 1.38 mm FWHM in the transverse and axial directions. The maximum likelihood expectation maximization (ML-EM) reconstructed image of a point source in air, averaged 0.81 ± 0.11 mm FWHM. The peak noise equivalent count rate (NECR) for the mouse-sized phantom was 44 kcps for a total activity of 2.9 MBq (78 µCi) and the scatter fraction was 11%. For the CT subsystem, the value of the modulation transfer function (MTF) at 10% was 2.05 cycles/mm. Conclusion: The overall performance demonstrates that the G8 can produce high quality images for molecular imaging based biomedical research. Copyright © 2018 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Comparison of DWI and PET/CT in evaluation of lymph node metastasis in uterine cancer

PubMed Central

Kitajima, Kazuhiro; Yamasaki, Erena; Kaji, Yasushi; Murakami, Koji; Sugimura, Kazuro

2012-01-01

AIM: To investigate diffusion-weighted imaging (DWI) and positron emission tomography and computed tomography (PET/CT) with IV contrast for the preoperative evaluation of pelvic lymph node (LN) metastasis in uterine cancer. METHODS: Twenty-five patients with endometrial or cervical cancer who underwent both DWI and PET/CT before pelvic lymphadenectomy were included in this study. For area specific analysis, LNs were divided into eight regions: both common iliac, external iliac, internal iliac areas, and obturator areas. The classification for malignancy on DWI was a focally abnormal signal intensity in a location that corresponded to the LN chains on the T1WI and T2WI. The criterion for malignancy on PET/CT images was increased tracer uptake by the LN. RESULTS: A total of 36 pathologically positive LN areas were found in 9 patients. With DWI, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy for detecting metastatic LNs on an LN area-by-area analysis were 83.3%, 51.2%, 27.3%, 93.3% and 57.0%, respectively, while the corresponding values for PET/CT were 38.9%, 96.3%, 70.0%, 87.8% and 86.0%. Differences in sensitivity, specificity and accuracy were significant (P < 0.0005). CONCLUSION: DWI showed higher sensitivity and lower specificity than PET/CT. Neither DWI nor PET/CT were sufficiently accurate to replace lymphadenectomy. PMID:22761980

Adrenal glands in hypovolemic shock: preservation of contrast enhancement at dynamic computed tomography.

PubMed

Ito, Katsuyoshi; Higashi, Hiroki; Kanki, Akihiko; Tamada, Tsutomu; Yamashita, Takenori; Yamamoto, Akira; Watanabe, Shigeru

2010-07-01

To evaluate contrast enhancement effects of the adrenal glands at dynamic computed tomography (CT) in adult severe trauma patients with hypovolemic shock in comparison with patients without hypovolemic shock. This study population included a total of 74 patients with (n = 24) and without (n = 50) blunt trauma and hypovolemic shock. Measurement of CT attenuation values of the adrenal gland and calculation of the enhancement washout percentages were performed. The mean +/- SD CT attenuation values of the adrenal glands in the arterial phase of dynamic CT in patients with hypovolemic shock (137.3 +/- 41.7 Hounsfield unit [HU]) were not significantly different (P = 0.16) from those in control subjects (127.3 +/- 19.6 HU). The mean CT attenuation values of the adrenal glands in the delayed phase of dynamic CT in patients with hypovolemic shock (82.0 +/- 14.7 HU) were also not significantly different (P = 0.89) from those in control subjects (82.4 +/- 10.0 HU). The mean percentage (35%) of enhancement washout of the adrenal glands in patients with hypovolemic shock was not significantly different (P = 0.81) from that (34%) in control subjects. Contrast enhancement effects of the adrenal glands at contrast-enhanced dynamic CT in patients with hypovolemic shock were similar to those in control subjects, indicating the preserved enhancement and perfusion of the adrenal gland rather than intense and persistent enhancement in patients with hypovolemic shock.

A pore-scale study of fracture dynamics in rock using X-ray micro-CT under ambient freeze-thaw cycling.

PubMed

De Kock, Tim; Boone, Marijn A; De Schryver, Thomas; Van Stappen, Jeroen; Derluyn, Hannelore; Masschaele, Bert; De Schutter, Geert; Cnudde, Veerle

2015-03-03

Freeze-thaw cycling stresses many environments which include porous media such as soil, rock and concrete. Climate change can expose new regions and subject others to a changing freeze-thaw frequency. Therefore, understanding and predicting the effect of freeze-thaw cycles is important in environmental science, the built environment and cultural heritage preservation. In this paper, we explore the possibilities of state-of-the-art micro-CT in studying the pore scale dynamics related to freezing and thawing. The experiments show the development of a fracture network in a porous limestone when cooling to -9.7 °C, at which an exothermal temperature peak is a proxy for ice crystallization. The dynamics of the fracture network are visualized with a time frame of 80 s. Theoretical assumptions predict that crystallization in these experiments occurs in pores of 6-20.1 nm under transient conditions. Here, the crystallization-induced stress exceeds rock strength when the local crystal fraction in the pores is 4.3%. The location of fractures is strongly related to preferential water uptake paths and rock texture, which are visually identified. Laboratory, continuous X-ray micro-CT scanning opens new perspectives for the pore-scale study of ice crystallization in porous media as well as for environmental processes related to freeze-thaw fracturing.

Diagnostic value of CT-localizer and axial low-dose computed tomography for the detection of drug body packing.

PubMed

Aissa, Joel; Kohlmeier, Antonia; Rubbert, Christian; Hohn, Ulrich; Blondin, Dirk; Schleich, Christoph; Kröpil, Patric; Boos, Johannes; Antoch, Gerald; Miese, Falk

2016-01-01

The purpose of this study was to assess the diagnostic performance of CT-localizers in the detection of intracorporal containers. This study was approved by the research ethics committee of our clinic. From March 2012 to March 2013, 108 subjects were referred to our institute with suspected body packing. The CT-localizer and the axial CT-images were compared by two blinded observers retrospectively. Presence of body packs was assessed in consensus. Sensitivity and specificity, PPV and NPV of the CT-localizer were calculated. Packets were detected in the CT-localizer of 19 suspects. In 28 of 108 cases packs were detected in axial CT-images. Sensitivity of CT-localizer for detection of packs was 0.68, and specificity was 1.00. There were no cases rated as false positive. The PPV was 1.0 and the NPV was 0.89. The omission of the axial CT-images would have led to a mean radiation dose reduction of 1.94 ± 0.5 mSv. The value of CT-localizers lies in their high PPV. Localizers are limited by low sensitivity, compared to axial CT-images in screening of potential body packers. However, in positive cases their high PPV may possibly allow to omit the complete axial abdominal CT to achieve even lower radiation exposure. Copyright © 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Assessment of regional lung functional impairment with co-registered respiratory-gated ventilation/perfusion SPET-CT images: initial experiences.

PubMed

Suga, Kazuyoshi; Yasuhiko, Kawakami; Zaki, Mohammed; Yamashita, Tomio; Seto, Aska; Matsumoto, Tsuneo; Matsunaga, Naofumi

2004-02-01

In this study, respiratory-gated ventilation and perfusion single-photon emission tomography (SPET) were used to define regional functional impairment and to obtain reliable co-registration with computed tomography (CT) images in various lung diseases. Using a triple-headed SPET unit and a physiological synchroniser, gated perfusion SPET was performed in a total of 78 patients with different pulmonary diseases, including metastatic nodules (n = 15); in 34 of these patients, it was performed in combination with gated technetium-99m Technegas SPET. Projection data were acquired using 60 stops over 120 degrees for each detector. Gated end-inspiration and ungated images were reconstructed from 1/8 data centered at peak inspiration for each regular respiratory cycle and full respiratory cycle data, respectively. Gated images were registered with tidal inspiration CT images using automated three-dimensional (3D) registration software. Registration mismatch was assessed by measuring 3D distance of the centroid of the nine selected round perfusion-defective nodules. Gated SPET images were completed within 29 min, and increased the number of visible ventilation and perfusion defects by 9.7% and 17.2%, respectively, as compared with ungated images; furthermore, lesion-to-normal lung contrast was significantly higher on gated SPET images. In the nine round perfusion-defective nodules, gated images yielded a significantly better SPET-CT match compared with ungated images (4.9 +/- 3.1 mm vs 19.0 +/- 9.1 mm, P<0.001). The co-registered SPET-CT images allowed accurate perception of the location and extent of each ventilation/perfusion defect on the underlying CT anatomy, and characterised the pathophysiology of the various diseases. By reducing respiratory motion effects and enhancing perfusion/ventilation defect clarity, gated SPET can provide reliable co-registered images with CT images to accurately characterise regional functional impairment in various lung diseases.

Molecular imaging of malignant tumor metabolism: whole-body image fusion of DWI/CT vs. PET/CT.

PubMed

Reiner, Caecilia S; Fischer, Michael A; Hany, Thomas; Stolzmann, Paul; Nanz, Daniel; Donati, Olivio F; Weishaupt, Dominik; von Schulthess, Gustav K; Scheffel, Hans

2011-08-01

To prospectively investigate the technical feasibility and performance of image fusion for whole-body diffusion-weighted imaging (wbDWI) and computed tomography (CT) to detect metastases using hybrid positron emission tomography/computed tomography (PET/CT) as reference standard. Fifty-two patients (60 ± 14 years; 18 women) with different malignant tumor disease examined by PET/CT for clinical reasons consented to undergo additional wbDWI at 1.5 Tesla. WbDWI was performed using a diffusion-weighted single-shot echo-planar imaging during free breathing. Images at b = 0 s/mm(2) and b = 700 s/mm(2) were acquired and apparent diffusion coefficient (ADC) maps were generated. Image fusion of wbDWI and CT (from PET/CT scan) was performed yielding for wbDWI/CT fused image data. One radiologist rated the success of image fusion and diagnostic image quality. The presence or absence of metastases on wbDWI/CT fused images was evaluated together with the separate wbDWI and CT images by two different, independent radiologists blinded to results from PET/CT. Detection rate and positive predictive values for diagnosing metastases was calculated. PET/CT examinations were used as reference standard. PET/CT identified 305 malignant lesions in 39 of 52 (75%) patients. WbDWI/CT image fusion was technically successful and yielded diagnostic image quality in 73% and 92% of patients, respectively. Interobserver agreement for the evaluation of wbDWI/CT images was κ = 0.78. WbDWI/CT identified 270 metastases in 43 of 52 (83%) patients. Overall detection rate and positive predictive value of wbDWI/CT was 89% (95% CI, 0.85-0.92) and 94% (95% CI, 0.92-0.97), respectively. WbDWI/CT image fusion is technically feasible in a clinical setting and allows the diagnostic assessment of metastatic tumor disease detecting nine of 10 lesions as compared with PET/CT. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

SU-F-I-59: Quality Assurance Phantom for PET/CT Alignment and Attenuation Correction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, T; Hamacher, K

2016-06-15

Purpose: This study utilizes a commercial PET/CT phantom to investigate two specific properties of a PET/CT system: the alignment accuracy of PET images with those from CT used for attenuation correction and the accuracy of this correction in PET images. Methods: A commercial PET/CT phantom consisting of three aluminum rods, two long central cylinders containing uniform activity, and attenuating materials such as air, water, bone and iodine contrast was scanned using a standard PET/CT protocol. Images reconstructed with 2 mm slice thickness and a 512 by 512 matrix were obtained. The center of each aluminum rod in the PET andmore » CT images was compared to evaluate alignment accuracy. ROIs were drawn on transaxial images of the central rods at each section of attenuating material to determine the corrected activity (in BQML). BQML values were graphed as a function of slice number to provide a visual representation of the attenuation-correction throughout the whole phantom. Results: Alignment accuracy is high between the PET and CT images. The maximum deviation between the two in the axial plane is less than 1.5 mm, which is less than the width of a single pixel. BQML values measured along different sections of the large central rods are similar among the different attenuating materials except iodine contrast. Deviation of BQML values in the air and bone sections from the water section is less than 1%. Conclusion: Accurate alignment of PET and CT images is critical to ensure proper calculation and application of CT-based attenuation correction. This study presents a simple and quick method to evaluate the two with a single acquisition. As the phantom also includes spheres of increasing diameter, this could serve as a straightforward means to annually evaluate the status of a modern PET/CT system.« less

The usefulness of fluorine-18 fluorodeoxyglucose PET in the detection of recurrence in patients with differentiated thyroid cancer with elevated thyroglobulin and negative radioiodine whole-body scan.

PubMed

Stangierski, Adam; Kaznowski, Jaroslaw; Wolinski, Kosma; Jodlowska, Elzbieta; Michaliszyn, Piotr; Kubiak, Katarzyna; Czepczynski, Rafal; Ruchala, Marek

2016-09-01

PET/computed tomography (CT) using fluorine-18 fluorodeoxyglucose (F-FDG) has been used in the diagnosis of recurrence and metastases of differentiated thyroid cancer (DTC) in cases of negative whole-body scan (WBS) despite elevated concentrations of stimulated thyroglobulin (Tg). To assess the utility of PET/CT in the detection of recurrence among patients with DTC with increased Tg levels and negative results of WBS. PET/CT results were retrospectively analyzed in patients with DTC with increased Tg and negative results of WBS as well as negative cervical ultrasonography and chest radiography. PET-CT was performed 1-2 weeks after recent diagnostics under conditions of endogenous or exogenous thyroid-stimulating hormone stimulation. PET/CT was performed using a Discovery ST scanner 1 h after an intravenously F-FDG injection (activity 4-5 MBq/kg). To determine the cutoff value of Tg, receiver operating characteristic curves were analyzed. Sixty-nine patients with DTC (48 women, 21 men) aged 22-83 years (mean 50.9±17.5 years) were qualified. In 44 patients (63.8%), PET/CT indicated lesions of DTC. Thirty (43.5%) patients had F-FDG positive findings. In the remaining 14 patients (20.3%), lesions were found in CT only. Patients with a positive PET/CT scan had significantly higher Tg values than patients with a negative PET/CT (mean 143.8 vs. 26.5 ng/ml, P=0.03). The cutoff value of Tg concentration measured with the receiver operating characteristic analysis was 32.9 ng/ml. PET/CT is a useful tool in the detection of recurrence among thyroid cancer patients in cases of conflicting results of standard procedures, particularly for those with high Tg levels and negative WBS. The probability of obtaining a positive PET-CT result increases with the level of Tg.

18F-FDG PET/CT as a staging procedure in primary stage II and III breast cancer: comparison with conventional imaging techniques.

PubMed

Koolen, Bas B; Vrancken Peeters, Marie-Jeanne T F D; Aukema, Tjeerd S; Vogel, Wouter V; Oldenburg, Hester S A; van der Hage, Jos A; Hoefnagel, Cornelis A; Stokkel, Marcel P M; Loo, Claudette E; Rodenhuis, Sjoerd; Rutgers, Emiel J Th; Valdés Olmos, Renato A

2012-01-01

The aim of the present study was to investigate if 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) outperforms conventional imaging techniques for excluding distant metastases prior to neoadjuvant chemotherapy (NAC) treatment in patients with stage II and III breast cancer. Second, we assessed the clinical importance of false positive findings. One hundred and fifty four patients with stage II or III breast cancer, scheduled to receive NAC, underwent an 18F-FDG PET/CT scan and conventional imaging, consisting of bone scintigraphy, ultrasound of the liver, and chest radiography. Suspect additional lesions at staging examination were confirmed by biopsy and histopathology and/or additional imaging. Metastases that were detected within 6 months after the PET/CT scan were considered evidence of occult metastasis, missed by staging examination. Forty-two additional distant lesions were seen in 25 patients with PET/CT and could be confirmed in 20 (13%) of 154 patients. PET/CT was false positive for 8 additional lesions (19%) and misclassified the presence of metastatic disease in 5 (3%) of 154 patients. In 16 (80%) of 20 patients, additional lesions were exclusively seen with PET/CT, leading to a change in treatment in 13 (8%) of 154 patients. In 129 patients with a negative staging PET/CT, no metastases developed during the follow-up of 9.0 months. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PET/CT in the detection of additional distant lesions in patients with stage II or III breast cancer are 100, 96, 80, 100, and 97%, respectively. FDG PET/CT is superior to conventional imaging techniques in the detection of distant metastases in patients with untreated stage II or III breast cancer and is associated with a low false positive rate. PET/CT may be of additional value in the staging of breast cancer prior to NAC.

Life cycle assessment of mobility options using wood based fuels--comparison of selected environmental effects and costs.

PubMed

Weinberg, Jana; Kaltschmitt, Martin

2013-12-01

An environmental assessment and a cost analysis were conducted for mobility options using electricity, hydrogen, ethanol, Fischer-Tropsch diesel and methane derived from wood. Therefore, the overall life cycle with regard to greenhouse gas emissions, acidifying emissions and fossil energy demand as well as costs is analysed. The investigation is carried out for mobility options in 2010 and gives an outlook to the year 2030. Results show that methane utilization in the car is beneficial with regard to environmental impacts (e.g. 58.5 g CO2-eq./km) and costs (23.1 €-ct./km) in 2010, especially in comparison to hydrogen usage (132.4 g CO2-eq./km and 63.9 €-ct./km). The electric vehicle construction has high environmental impacts and costs compared to conventional vehicles today, but with technical improvements and further market penetration, battery electric vehicles can reach the level of concepts with combustion engines in future applications (e.g. cost decrease from 38.7 to 23.4 €-ct./km). Copyright © 2013 Elsevier Ltd. All rights reserved.

Validation of a low dose simulation technique for computed tomography images.

PubMed

Muenzel, Daniela; Koehler, Thomas; Brown, Kevin; Zabić, Stanislav; Fingerle, Alexander A; Waldt, Simone; Bendik, Edgar; Zahel, Tina; Schneider, Armin; Dobritz, Martin; Rummeny, Ernst J; Noël, Peter B

2014-01-01

Evaluation of a new software tool for generation of simulated low-dose computed tomography (CT) images from an original higher dose scan. Original CT scan data (100 mAs, 80 mAs, 60 mAs, 40 mAs, 20 mAs, 10 mAs; 100 kV) of a swine were acquired (approved by the regional governmental commission for animal protection). Simulations of CT acquisition with a lower dose (simulated 10-80 mAs) were calculated using a low-dose simulation algorithm. The simulations were compared to the originals of the same dose level with regard to density values and image noise. Four radiologists assessed the realistic visual appearance of the simulated images. Image characteristics of simulated low dose scans were similar to the originals. Mean overall discrepancy of image noise and CT values was -1.2% (range -9% to 3.2%) and -0.2% (range -8.2% to 3.2%), respectively, p>0.05. Confidence intervals of discrepancies ranged between 0.9-10.2 HU (noise) and 1.9-13.4 HU (CT values), without significant differences (p>0.05). Subjective observer evaluation of image appearance showed no visually detectable difference. Simulated low dose images showed excellent agreement with the originals concerning image noise, CT density values, and subjective assessment of the visual appearance of the simulated images. An authentic low-dose simulation opens up opportunity with regard to staff education, protocol optimization and introduction of new techniques.

Convolutional auto-encoder for image denoising of ultra-low-dose CT.

PubMed

Nishio, Mizuho; Nagashima, Chihiro; Hirabayashi, Saori; Ohnishi, Akinori; Sasaki, Kaori; Sagawa, Tomoyuki; Hamada, Masayuki; Yamashita, Tatsuo

2017-08-01

The purpose of this study was to validate a patch-based image denoising method for ultra-low-dose CT images. Neural network with convolutional auto-encoder and pairs of standard-dose CT and ultra-low-dose CT image patches were used for image denoising. The performance of the proposed method was measured by using a chest phantom. Standard-dose and ultra-low-dose CT images of the chest phantom were acquired. The tube currents for standard-dose and ultra-low-dose CT were 300 and 10 mA, respectively. Ultra-low-dose CT images were denoised with our proposed method using neural network, large-scale nonlocal mean, and block-matching and 3D filtering. Five radiologists and three technologists assessed the denoised ultra-low-dose CT images visually and recorded their subjective impressions of streak artifacts, noise other than streak artifacts, visualization of pulmonary vessels, and overall image quality. For the streak artifacts, noise other than streak artifacts, and visualization of pulmonary vessels, the results of our proposed method were statistically better than those of block-matching and 3D filtering (p-values < 0.05). On the other hand, the difference in the overall image quality between our proposed method and block-matching and 3D filtering was not statistically significant (p-value = 0.07272). The p-values obtained between our proposed method and large-scale nonlocal mean were all less than 0.05. Neural network with convolutional auto-encoder could be trained using pairs of standard-dose and ultra-low-dose CT image patches. According to the visual assessment by radiologists and technologists, the performance of our proposed method was superior to that of large-scale nonlocal mean and block-matching and 3D filtering.

Predictive value of flat-panel CT for haemorrhagic transformations in patients with acute stroke treated with thrombectomy.

PubMed

Rouchaud, Aymeric; Pistocchi, Silvia; Blanc, Raphaël; Engrand, Nicolas; Bartolini, Bruno; Piotin, Michel

2014-03-01

Haemorrhagic transformations are pejorative for patients with acute ischaemic stroke (AIS). We estimated flat-panel CT performances to detect brain parenchymal hyperdense lesions immediately after mechanical thrombectomy directly on the angiography table in patients with AIS, and its ability to predict haemorrhagic transformation. We also evaluated an easy-reading protocol for post-procedure flat-panel CT evaluation by clinicians to enable them to determine the potential risk of haemorrhage. Two neuroradiologists retrospectively reviewed post-procedural flat-panel CT and 24 h follow-up imaging. We evaluated hyperdense lesions on flat-panel CT to predict the occurrence of haemorrhagic transformation within 24 h detected with conventional imaging. Of 63 patients, 60.3% presented post-procedural parenchymal hyperdensity and 54.0% had haemorrhagic transformation. Significantly more patients with hyperdense lesions on post-thrombectomy flat-panel CT presented haemorrhagic transformation (84.2% vs 8.0%; p<0.0001). No significant haemorrhagic transformations were detected for patients without parenchymal hyperdensity. Sensitivity and specificity of hyperdense lesions on flat-panel CT for the prediction of haemorrhagic transformation were 94.1% (80.3-99.3%) and 79.3% (60.3-92.0%), respectively. The positive and negative predictive values for the occurrence of haemorrhage were 84.2% (68.8-94.0%) and 92.0% (74.0-99.0%), respectively. For significant parenchymal haemorrhage type 2, sensitivity and negative predictive values were 100%. We observed good homogeneity between the different readers. Hyperdensity on post-procedural flat-panel CT was associated with a tendency for higher risk of death and lower risk of good clinical outcome. Flat-panel CT appears to be a good tool to detect brain parenchymal hyperdensities after mechanical thrombectomy in patients with AIS and to predict haemorrhagic transformation.

Development of Monte Carlo simulations to provide scanner-specific organ dose coefficients for contemporary CT

NASA Astrophysics Data System (ADS)

Jansen, Jan T. M.; Shrimpton, Paul C.

2016-07-01

The ImPACT (imaging performance assessment of CT scanners) CT patient dosimetry calculator is still used world-wide to estimate organ and effective doses (E) for computed tomography (CT) examinations, although the tool is based on Monte Carlo calculations reflecting practice in the early 1990’s. Subsequent developments in CT scanners, definitions of E, anthropomorphic phantoms, computers and radiation transport codes, have all fuelled an urgent need for updated organ dose conversion factors for contemporary CT. A new system for such simulations has been developed and satisfactorily tested. Benchmark comparisons of normalised organ doses presently derived for three old scanners (General Electric 9800, Philips Tomoscan LX and Siemens Somatom DRH) are within 5% of published values. Moreover, calculated normalised values of CT Dose Index for these scanners are in reasonable agreement (within measurement and computational uncertainties of  ±6% and  ±1%, respectively) with reported standard measurements. Organ dose coefficients calculated for a contemporary CT scanner (Siemens Somatom Sensation 16) demonstrate potential deviations by up to around 30% from the surrogate values presently assumed (through a scanner matching process) when using the ImPACT CT Dosimetry tool for newer scanners. Also, illustrative estimates of E for some typical examinations and a range of anthropomorphic phantoms demonstrate the significant differences (by some 10’s of percent) that can arise when changing from the previously adopted stylised mathematical phantom to the voxel phantoms presently recommended by the International Commission on Radiological Protection (ICRP), and when following the 2007 ICRP recommendations (updated from 1990) concerning tissue weighting factors. Further simulations with the validated dosimetry system will provide updated series of dose coefficients for a wide range of contemporary scanners.

Value of planar lymphoscintigraphy versus SPECT/CT in evaluation of sentinel lymph node in trunk melanoma - one center, large series, retrospective study.

PubMed

Benke, Małgorzata; Wocial, Krzysztof; Lewandowska, Weronika; Rutkowski, Piotr Łukasz; Teterycz, Paweł; Jarek, Piotr; Dedecjus, Marek

2018-06-29

Background Localization and histopathological examination of sentinel lymph node (SLN) is a standard of melanoma treatment. The first stage of identification of the SLN is the preoperative lymphoscintigraphy. The aim of this study was to assess and compare diagnostic value of planar lymphoscintigraphy (PL) and SPECT/CT in sentinel lymph node biopsy (SLNB) procedure performed in patients with cutaneous trunk melanoma. Material and Methods Between 2015 and 2016, patients with trunk melanoma (N=255, F/M 95/160), aged from 17 to 88 after an excisional biopsy, with primary tumor ≥ pT1b (AJCC 2009, median Breslow thickness 2.0± 3.13) were included in the study. In all the patients PL was followed by SPECT/CT 1-3 h after injection of 99mTc- colloid particles, and SLNB was performed the next day. Results SPECT-CT revealed 78 (18.6%) SLN more than PL, and in 40 patients showed additional lymph drainage regions leading to surgical adjustments. In 18 patients (7.1%) SPECT-CT revealed SLN not visible in the PL (false-negative PL) and in 22 patients (8.6%), foci of uptake interpreted in PL as hot SLNs were found to be non-nodal sites of uptake when assessed on SPECT/CT (false positive PL). SPECT-CT vs. PL mismatch was observed in 31 patients (12.2%) and was the most common in patients with primary lesions located in the anterior inferior medial region (75%). Conclusions Results of the presented study indicates the high diagnostic value of SPECT-CT in assessment of SLNs and proved that SPECT-CT increases the sensitivity and accuracy of SLN identification as compared to PL even in very experienced hands.

Management Strategies for Dual-Career Couples.

ERIC Educational Resources Information Center

Kater, Donna

1985-01-01

Suggestions are presented that focus on strategies to alleviate those stresses arising from internal sources. These strategies include enhancing communication skills, relieving role overload, and minimizing multiple role-cycling. (CT)

SU-F-J-76: Evaluation of the Performance of Different Deformable Image Registration Algorithms in Helical, Axial and Cone-Beam CT Images of a Mobile Phantom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jaskowiak, J; Ahmad, S; Ali, I

Purpose: To investigate quantitatively the performance of different deformable-image-registration algorithms (DIR) with helical (HCT), axial (ACT) and cone-beam CT (CBCT) by evaluating the variations in the CT-numbers and lengths of targets moving with controlled motion-patterns. Methods: Four DIR-algorithms including demons, fast-demons, Horn-Schunk and Locas-Kanade from the DIRART-software are used to register CT-images of a mobile-phantom. A mobile-phantom is scanned with different imaging techniques that include helical, axial and cone-beam CT. The phantom includes three targets with different lengths that are made from water-equivalent material and inserted in low-density-foam which is moved with adjustable motion-amplitudes and frequencies. Results: Most of themore » DIR-algorithms are able to produce the lengths of the stationary-targets, however, they do not produce the CT-number values in CBCT. The image-artifacts induced by motion are more regular in CBCT imaging where the mobile-target elongation increases linearly with motion-amplitude. In ACT and HCT, the motion-artifacts are irregular where some mobile -targets are elongated or shrunk depending on the motion-phase during imaging. The DIR-algorithms are successful in deforming the images of the mobile-targets to the images of the stationary-targets producing the CT-number values and length of the target for motion-amplitudes < 20 mm. Similarly in ACT, all DIR-algorithms produced the actual CT-number and length of the stationary-targets for motion-amplitudes < 15 mm. As stronger motion-artifacts are induced in HCT and ACT, DIR-algorithms fail to produce CT-values and shape of the stationary-targets and fast-demons-algorithm has worst performance. Conclusion: Most of DIR-algorithms produce the CT-number values and lengths of the stationary-targets in HCT and ACT images that has motion-artifacts induced by small motion-amplitudes. As motion-amplitudes increase, the DIR-algorithms fail to deform mobile-target images to the stationary-images in HCT and ACT. In CBCT, DIR-algorithms are successful in producing length and shape of the stationary-targets, however, they fail to produce the accurate CT-number level.« less

Development and validation of segmentation and interpolation techniques in sinograms for metal artifact suppression in CT.

PubMed

Veldkamp, Wouter J H; Joemai, Raoul M S; van der Molen, Aart J; Geleijns, Jacob

2010-02-01

Metal prostheses cause artifacts in computed tomography (CT) images. The purpose of this work was to design an efficient and accurate metal segmentation in raw data to achieve artifact suppression and to improve CT image quality for patients with metal hip or shoulder prostheses. The artifact suppression technique incorporates two steps: metal object segmentation in raw data and replacement of the segmented region by new values using an interpolation scheme, followed by addition of the scaled metal signal intensity. Segmentation of metal is performed directly in sinograms, making it efficient and different from current methods that perform segmentation in reconstructed images in combination with Radon transformations. Metal signal segmentation is achieved by using a Markov random field model (MRF). Three interpolation methods are applied and investigated. To provide a proof of concept, CT data of five patients with metal implants were included in the study, as well as CT data of a PMMA phantom with Teflon, PVC, and titanium inserts. Accuracy was determined quantitatively by comparing mean Hounsfield (HU) values and standard deviation (SD) as a measure of distortion in phantom images with titanium (original and suppressed) and without titanium insert. Qualitative improvement was assessed by comparing uncorrected clinical images with artifact suppressed images. Artifacts in CT data of a phantom and five patients were automatically suppressed. The general visibility of structures clearly improved. In phantom images, the technique showed reduced SD close to the SD for the case where titanium was not inserted, indicating improved image quality. HU values in corrected images were different from expected values for all interpolation methods. Subtle differences between interpolation methods were found. The new artifact suppression design is efficient, for instance, in terms of preserving spatial resolution, as it is applied directly to original raw data. It successfully reduced artifacts in CT images of five patients and in phantom images. Sophisticated interpolation methods are needed to obtain reliable HU values close to the prosthesis.

Value of ¹⁸F-FDG PET/CT in the diagnosis of primary gastric cancer via stomach distension.

PubMed

Ma, Quanmei; Xin, Jun; Zhao, Zhoushe; Guo, Qiyong; Yu, Shupeng; Xu, Weina; Liu, Changping; Zhai, Wei

2013-06-01

To clarify the usefulness of (18)F-FDG PET/CT for detecting primary gastric cancer via gastric distention using a mixture of milk and Diatrizoate Meglumine. A total of 68 patients (male: 47, female: 21; age: 41-87 years) suspected of gastric carcinoma underwent (18)F-FDG PET/CT imaging. After whole-body PET/CT imaging in a fasting state, the patients drank a measured amount of milk with Diatrizoate Meglumine. Local gastric district PET/CT imaging was performed 30 min later. The imaging was analyzed by semi-quantitative analysis, standardized uptake value (SUV) of the primary tumor was measured in a region of interest. The diagnosis results were confirmed by gastroscopy, pathology, and follow-up results. Of the 68 patients, 56 malignant gastric neoplasm patients (male: 37, female: 19) were conformed. The sensitivity, specificity, positive predictive value and negative predictive value of fasting whole-body PET/CT imaging for a primary malignant tumor were 92.9%, 75.0%, 94.5%, and 69.0%, respectively. The values for distension with a mixture of milk and Diatrizoate Meglumine were 91.1%, 91.7%, 98.1%, and 68.8%, respectively. The area under the curve was 0.919 ± 0.033 and 0.883 ± 0.066 for the diagnosis of gastric cancer with SUVmax in a fasting state and after intake of mixture respectively, the differences were not statistically significant (P=0.359). Using gastric distension with a mixture of milk and Diatrizoate Meglumine, the mean ratio of the lesion's SUVmax to the adjacent gastric wall SUVmax increased significantly from 3.30 ± 3.05 to 13.50 ± 15.05, which was statistically significant (P<0.001). (18)F-FDG PET/CT imaging is highly accurate for the diagnosis of primary gastric carcinoma. Gastric distention can display the lesions more clearly, however, it cannot significantly improve diagnostic accuracy. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Variable rainfall intensity and tillage effects on runoff, sediment, and carbon losses from a loamy sand under simulated rainfall.

PubMed

Truman, C C; Strickland, T C; Potter, T L; Franklin, D H; Bosch, D D; Bednarz, C W

2007-01-01

The low-carbon, intensively cropped Coastal Plain soils of Georgia are susceptible to runoff, soil loss, and drought. Reduced tillage systems offer the best management tool for sustained row crop production. Understanding runoff, sediment, and chemical losses from conventional and reduced tillage systems is expected to improve if the effect of a variable rainfall intensity storm was quantified. Our objective was to quantify and compare effects of a constant (Ic) intensity pattern and a more realistic, observed, variable (Iv) rainfall intensity pattern on runoff (R), sediment (E), and carbon losses (C) from a Tifton loamy sand cropped to conventional-till (CT) and strip-till (ST) cotton (Gossypium hirsutum L.). Four treatments were evaluated: CT-Ic, CT-Iv, ST-Ic, and ST-Iv, each replicated three times. Field plots (n=12), each 2 by 3 m, were established on each treatment. Each 6-m2 field plot received simulated rainfall at a constant (57 mm h(-1)) or variable rainfall intensity pattern for 70 min (12-run ave.=1402 mL; CV=3%). The Iv pattern represented the most frequent occurring intensity pattern for spring storms in the region. Compared with CT, ST decreased R by 2.5-fold, E by 3.5-fold, and C by 7-fold. Maximum runoff values for Iv events were 1.6-fold higher than those for Ic events and occurred 38 min earlier. Values for Etot and Ctot for Iv events were 19-36% and 1.5-fold higher than corresponding values for Ic events. Values for Emax and Cmax for Iv events were 3-fold and 4-fold higher than corresponding values for Ic events. Carbon enrichment ratios (CER) were or=1.0 for CT plots (except for first 20 min). Maximum CER for CT-Ic, CT-Iv, ST-Ic, and ST-Iv were 2.0, 2.2, 1.0, and 1.2, respectively. Transport of sediment, carbon, and agrichemicals would be better understood if variable rainfall intensity patterns derived from natural rainfall were used in rainfall simulations to evaluate their fate and transport from CT and ST systems.

SU-E-J-210: Characterizing Tissue Equivalent Materials for the Development of a Dual MRI-CT Heterogeneous Anthropomorphic Phantom Designed Specifically for MRI Guided Radiotherapy Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinmann, A; Stafford, R; Yung, J

Purpose: MRI guided radiotherapy (MRIgRT) is an emerging technology which will eventually require a proficient quality auditing system. Due to different principles in which MR and CT acquire images, there is a need for a multi-imaging-modality, end-to-end QA phantom for MRIgRT. The purpose of this study is to identify lung, soft tissue, and tumor equivalent substitutes that share similar human-like CT and MR properties (i.e. Hounsfield units and relaxation times). Methods: Materials of interested such as common CT QA phantom materials, and other proprietary gels/silicones from Polytek, SmoothOn, and CompositeOne were first scanned on a GE 1.5T Signa HDxT MR.more » Materials that could be seen on both T1-weighted and T2-weighted images were then scanned on a GE Lightspeed RT16 CT simulator and a GE Discovery 750HD CT scanner and their HU values were then measured. The materials with matching HU values of lung (−500 to −700HU), muscle (+40HU) and soft tissue (+100 to +300HU) were further scanned on GE 1.5T Signa HDx to measure their T1 and T2 relaxation times from varying parameters of TI and TE. Results: Materials that could be visualized on T1-weighted and T2-weighted images from a 1.5T MR unit and had an appropriate average CT number, −650, −685, 46,169, and 168 HUs were: compressed cork saturated with water, Polytek Platsil™ Gel-00 combined with mini styrofoam balls, radiotherapy bolus material, SmoothOn Dragon-Skin™ and SmoothOn Ecoflex™, respectively. Conclusion: Post processing analysis is currently being performed to accurately map T1 and T2 values for each material tested. From previous MR visualization and CT examinations it is expected that Dragon-Skin™, Ecoflex™ and bolus will have values consistent with tissue and tumor substitutes. We also expect compressed cork statured with water, and Polytek™-styrofoam combination to have approximate T1 and T2 values suitable for lung-equivalent materials.« less

Assessment of an organ‐based tube current modulation in thoracic computed tomography

PubMed Central

Sugai, Mai; Toyoda, Asami; Koshida, Haruka; Sakuta, Keita; Takata, Tadanori; Koshida, Kichiro; Iida, Hiroji; Matsui, Osamu

2012-01-01

Recently, specific computed tomography (CT) scanners have been equipped with organ‐based tube current modulation (TCM) technology. It is possible that organ‐based TCM will replace the conventional dose‐reduction technique of reducing the effective milliampere‐second. The aim of this study was to determine if organ‐based TCM could reduce radiation exposure to the breasts without compromising the image uniformity and beam hardening effect in thoracic CT examinations. Breast and skin radiation doses and the absorbed radiation dose distribution within a single section were measured with an anthropomorphic phantom and radiophotoluminescent glass dosimeters using four approaches to thoracic CT (reference, organ‐based TCM, copper shielding, and the combination of the above two techniques, hereafter referred to as the combination technique). The CT value and noise level were measured using the same calibration phantom. Organ‐based TCM and copper shielding reduced radiation doses to the breast by 23.7% and 21.8%, respectively. However, the CT value increased, especially in the anterior region, using copper shielding. In contrast, the CT value and noise level barely increased using organ‐based TCM. The combination technique reduced the radiation dose to the breast by 38.2%, but greatly increased the absorbed radiation dose from the central to the posterior regions. Moreover, the CT value increased in the anterior region and the noise level increased by more than 10% in the entire region. Therefore, organ‐based TCM can reduce radiation doses to breasts with only small increases in noise levels, making it preferable for specific groups of patients, such as children and young women. PACS numbers: 87.53.Bn; 87.57.Q‐; 87.57.qp PMID:22402390

Exploring the biological activity of condensed tannins and nutritional value of tree and shrub leaves from native species of the Argentinean Dry Chaco.

PubMed

García, Elisa M; Cherry, Nicole; Lambert, Barry D; Muir, James P; Nazareno, Mónica A; Arroquy, Jose I

2017-11-01

Tropical tree or shrub leaves are an important source of nutrients for ruminants and a potential source of biologically active compounds that may affect ruminal metabolism of nutrients. Therefore, eight woody species from the native flora of Argentinean Dry Chaco, rich in secondary compounds such as condensed tannins (CT), were assessed for their nutritional value, CT fractions and in vitro true digestibility of dry matter, as well as biological activity (BA). Differences among species were found in contents of total phenol, protein-precipitating phenols (PPP), bound proteins to PPP (BP) and BP/PPP (P < 0.0001). The BP/PPP ratio reveals differences among species in potential BA as indicated by protein precipitation. The major CT of each species were isolated and purified for use as a standard. Although Schinopsis balansae had the most (P ≤ 0.05) total CT (19.59% DM), Caesalpinia paraguariensis had greater (P ≤ 0.05) BA with the most PPP (530.21% dry matter). Larrea divaricata, at 0.97, followed by Acacia aroma, at 0.89, had CT with the highest (P ≤ 0.05) BP/PPP ratios, followed by Prosopis alba (0.59). There were differences in nutritive value and bioactivity among species. Those with the greatest CT were not necessarily those with the most BA. Caesalpinia paraguariensis, S. balansae and L. divaricata were the most promising species as native forage CT sources. Cercidiurm praecox (20.87% CP; 18.14% acid detergent fiber) and Prosopis nigra (19.00% CP; 27.96% acid detergent fiber) showed the best (P ≤ 0.05) nutritive values. According to their nutritive traits, these species might be complementary in grass-based ruminant diets. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Comparative 3D micro-CT and 2D histomorphometry analysis of dental implant osseointegration in the maxilla of minipigs.

PubMed

Bissinger, Oliver; Probst, Florian Andreas; Wolff, Klaus-Dietrich; Jeschke, Anke; Weitz, Jochen; Deppe, Herbert; Kolk, Andreas

2017-04-01

The bone implant contact (BIC) has traditionally been evaluated with histological methods. Thereupon, strong correlations of two-dimensional (2D) BIC have been detected between μCT and destructive histology. However, due to the high intra-sample variability in BIC values, one histological slice is not sufficient to represent 3D BIC. Therefore, our aim has been to correlate the averaged values of 3-4 histological sections to 3D μCT. Fifty-four implants inserted into the maxilla of 14 minipigs were evaluated. Two different time points were selected to assess the 3D BIC (distance to implant: 2-5 voxels), an inner ring (6-30 voxels) and an outer ring (55-100 voxels) using μCT (voxel size: 10 μm) and to correlate the values to histomorphometry. Strong correlations (p < 0.0001; 28 days, 56 days, total) were seen between μCT and histomorphometry concerning BIC (r = 0.84, r = 0.85, r = 0.83), the inner ring (r = 0.87, r = 0.87, r = 0.88) and the outer ring (r = 0.85, r = 0.85, r = 0.88). Closer to the implant, μCT values were higher compared with histomorphometry. Although 3-4 histological slices per implant seem to predict the 3D BIC, μCT might be advantageous because of its non-destructive 3D character. The healing time may not impact on the comparability. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Comparison of glomerular filtration rate determined by use of single-slice dynamic computed tomography and scintigraphy in cats.

PubMed

Schmidt, David M; Scrivani, Peter V; Dykes, Nathan L; Goldstein, Richard M; Erb, Hollis N; Reeves, Anthony P

2012-04-01

To compare estimation of glomerular filtration rate determined via conventional methods (ie, scintigraphy and plasma clearance of technetium Tc 99m pentetate) and dynamic single-slice computed tomography (CT). 8 healthy adult cats. Scintigraphy, plasma clearance testing, and dynamic CT were performed on each cat on the same day; order of examinations was randomized. Separate observers performed GFR calculations for scintigraphy, plasma clearance testing, or dynamic CT. Methods were compared via Bland-Altman plots and considered interchangeable and acceptable when the 95% limits of agreement (mean difference between methods ± 1.96 SD of the differences) were ≤ 0.7 mL/min/kg. Global GFR differed < 0.7 mL/min/kg in 5 of 8 cats when comparing plasma clearance testing and dynamic CT; the limits of agreement were 1.4 and -1.7 mL/min/kg. The mean ± SD difference was -0.2 ± 0.8 mL/min/kg, and the maximum difference was 1.6 mL/min/kg. The mean ± SD difference (absolute value) for percentage filtration by individual kidneys was 2.4 ± 10.5% when comparing scintigraphy and dynamic CT; the maximum difference was 20%, and the limits of agreement were 18% and 23% (absolute value). GFR estimation via dynamic CT exceeded the definition for acceptable clinical use, compared with results for conventional methods, which was likely attributable to sample size and preventable technical complications. Because 5 of 8 cats had comparable values between methods, further investigation of dynamic CT in a larger sample population with a wide range of GFR values should be performed.

[Changing the internal cost allocation (ICA) on DRG shares : Example of computed tomography in a university radiology setting].

PubMed

Wirth, K; Zielinski, P; Trinter, T; Stahl, R; Mück, F; Reiser, M; Wirth, S

2016-08-01

In hospitals, the radiological services provided to non-privately insured in-house patients are mostly distributed to requesting disciplines through internal cost allocation (ICA). In many institutions, computed tomography (CT) is the modality with the largest amount of allocation credits. The aim of this work is to compare the ICA to respective DRG (Diagnosis Related Groups) shares for diagnostic CT services in a university hospital setting. The data from four CT scanners in a large university hospital were processed for the 2012 fiscal year. For each of the 50 DRG groups with the most case-mix points, all diagnostic CT services were documented including their respective amount of GOÄ allocation credits and invoiced ICA value. As the German Institute for Reimbursement of Hospitals (InEK) database groups the radiation disciplines (radiology, nuclear medicine and radiation therapy) together and also lacks any modality differentiation, the determination of the diagnostic CT component was based on the existing institutional distribution of ICA allocations. Within the included 24,854 cases, 63,062,060 GOÄ-based performance credits were counted. The ICA relieved these diagnostic CT services by € 819,029 (single credit value of 1.30 Eurocent), whereas accounting by using DRG shares would have resulted in € 1,127,591 (single credit value of 1.79 Eurocent). The GOÄ single credit value is 5.62 Eurocent. The diagnostic CT service was basically rendered as relatively inexpensive. In addition to a better financial result, changing the current ICA to DRG shares might also mean a chance for real revenues. However, the attractiveness considerably depends on how the DRG shares are distributed to the different radiation disciplines of one institution.

Transcranial color-coded duplex sonography for evaluation of midline-shift after chronic-subdural hematoma evacuation (TEMASE): A prospective study.

PubMed

Cattalani, Andrea; Grasso, Vincenzo Maria; Vitali, Matteo; Gallesio, Ivan; Magrassi, Lorenzo; Barbanera, Andrea

2017-11-01

The incidence of chronic Subdural hematoma (cSDH) is increasing and its rate of recurrence varies from 5 to 33%. A postoperative brain midline-shift (MLS) on computed tomography (CT) equal or larger than 5mm is a risk factor for recurrence. Transcranial color-coded duplex sonography (TCCDS) is a noninvasive bedside reproducible technique useful to detect MLS. The aim of our study was to compare in patients affected by cSDH, the values of MLS obtained pre- and post-operatively by TCCDS and brain CT. 32 patients affected by cSDH entered the study between July 2016 and January 2017. MLS values obtained by TCCDS and brain CT were compared using Bland-Altman plot and linear regression analysis. Using the same techniques we also explored if the agreement between the two imaging modes was comparable in pre- and post-operative data pairs. 64 data pairs of MLS values obtained by TCCDS and CT were analysed. Bland-Altman diagrams did not show any systematic bias of the data and linear regression indicated a significant correlation between the two measures both before and after hematoma evacuation. In patients affected by cSDH, MLS values obtained before and after surgery by TCCDS are comparable to those obtained by CT; TCCDS might be considered an alternative to CT scan in the management of patients after cSDH evacuation. We suggest that close clinical bedside examination and TCCDS might be appropriate for the post-operative management of cSDH, reserving CT scan only to patients with overt clinical deterioration and/or increasing MLS. Copyright © 2017 Elsevier B.V. All rights reserved.

Ring test evaluation of the detection of influenza A virus in swine oral fluids by real-time reverse-transcription polymerase chain reaction and virus isolation

PubMed Central

Goodell, Christa K.; Zhang, Jianqiang; Strait, Erin; Harmon, Karen; Patnayak, Devi; Otterson, Tracy; Culhane, Marie; Christopher-Hennings, Jane; Clement, Travis; Leslie-Steen, Pamela; Hesse, Richard; Anderson, Joe; Skarbek, Kevin; Vincent, Amy; Kitikoon, Pravina; Swenson, Sabrina; Jenkins-Moore, Melinda; McGill, Jodi; Rauh, Rolf; Nelson, William; O’Connell, Catherine; Shah, Rohan; Wang, Chong; Main, Rodger; Zimmerman, Jeffrey J.

2016-01-01

The probability of detecting influenza A virus (IAV) in oral fluid (OF) specimens was calculated for each of 13 assays based on real-time reverse-transcription polymerase chain reaction (rRT-PCR) and 7 assays based on virus isolation (VI). The OF specimens were inoculated with H1N1 or H3N2 IAV and serially diluted 10-fold (10−1 to 10−8). Eight participating laboratories received 180 randomized OF samples (10 replicates × 8 dilutions × 2 IAV subtypes plus 20 IAV-negative samples) and performed the rRT-PCR and VI procedure(s) of their choice. Analysis of the results with a mixed-effect logistic-regression model identified dilution and assay as variables significant (P < 0.0001) for IAV detection in OF by rRT-PCR or VI. Virus subtype was not significant for IAV detection by either rRT-PCR (P = 0.457) or VI (P = 0.101). For rRT-PCR the cycle threshold (Ct) values increased consistently with dilution but varied widely. Therefore, it was not possible to predict VI success on the basis of Ct values. The success of VI was inversely related to the dilution of the sample; the assay was generally unsuccessful at lower virus concentrations. Successful swine health monitoring and disease surveillance require assays with consistent performance, but significant differences in reproducibility were observed among the assays evaluated. PMID:26733728

Discerning Viable from Nonviable Yersinia pestis pgm- and Bacillus anthracis Sterne using Propidium Monoazide in the Presence of White Powders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hess, Becky M.; Kaiser, Brooke LD; Sydor, Michael A.

ABSTRACT Aims To develop and optimize an assay to determine viability status of Bacillus anthracis Sterne and Yersinia pestis pgm- strains in the presence of white powders by coupling propidium monoazide (PMA) treatment with real-time PCR (qPCR) analysis. Methods and Results PMA selectively enters nonviable cells and binds DNA, thereby increasing qPCR assay cycle threshold (CT) values compared to untreated samples. Dye concentration, cell number and fitness, incubation time, inactivation methods, and assay buffer were optimized for B. anthracis Sterne and Y. pestis pgm-. Differences in CT values in nonviable cells compared to untreated samples were consistently > 9 formore » both B. anthracis Sterne vegetative cells and Y. pestis pgm- in the presence and absence of three different white powders. Our method eliminates the need for a DNA extraction step prior to detection by qPCR. Conclusions The developed assay enables simultaneous identification and viability assessment for B. anthracis Sterne and Y. pestis pgm- under laboratory conditions, even in the presence of white powders. Eliminating the DNA extraction step that is typically used reduces total assay time and labor requirements for sample analysis. Significance and Impact of the Study The method developed for simultaneous detection and viability assessment for B. anthracis and Y. pestis can be employed in forming decisions about the severity of a biothreat event or the safety of food. Keywords Bacillus anthracis, Yersinia pestis, Propidium Monoazide, qPCR, White Powders, Rapid Viability Detection« less

Development of real-time PCR assay for genetic identification of the mottled skate, Beringraja pulchra.

PubMed

Hwang, In Kwan; Lee, Hae Young; Kim, Min-Hee; Jo, Hyun-Su; Choi, Dong-Ho; Kang, Pil-Won; Lee, Yang-Han; Cho, Nam-Soo; Park, Ki-Won; Chae, Ho Zoon

2015-10-01

The mottled skate, Beringraja pulchra is one of the commercially important fishes in the market today. However, B. pulchra identification methods have not been well developed. The current study reports a novel real-time PCR method based on TaqMan technology developed for the genetic identification of B. pulchra. The mitochondrial cytochrome oxidase subunit 1 (COI) nucleotide sequences of 29 B. pulchra, 157 skates and rays reported in GenBank DNA database were comparatively analyzed and the COI sequences specific to B. pulchra was identified. Based on this information, a system of specific primers and Minor Groove Binding (MGB) TaqMan probe were designed. The assay successfully discriminated in 29 specimens of B. pulchra and 27 commercial samples with unknown species identity. For B. pulchra DNA, an average Threshold Cycle (Ct) value of 19.1±0.1 was obtained. Among 27 commercial samples, two samples showed average Ct values 19.1±0.0 and 26.7±0.1, respectively and were confirmed to be B. pulchra based on sequencing. The other samples tested showed undetectable or extremely weak signals for the target fragment, which was also consistent with the sequencing results. These results reveal that the method developed is a rapid and efficient tool to identify B. pulchra and might prevent fraud or mislabeling during the distribution of B. pulchra products. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The value of 99mTc-MAA SPECT/CT for lung shunt estimation in 90Y radioembolization: a phantom and patient study.

PubMed

Allred, Jonathan D; Niedbala, Jeremy; Mikell, Justin K; Owen, Dawn; Frey, Kirk A; Dewaraja, Yuni K

2018-06-15

A major toxicity concern in radioembolization therapy of hepatic malignancies is radiation-induced pneumonitis and sclerosis due to hepatopulmonary shunting of 90 Y microspheres. Currently, 99m Tc macroaggregated albumin ( 99m Tc-MAA) imaging is used to estimate the lung shunt fraction (LSF) prior to treatment. The aim of this study was to evaluate the accuracy/precision of LSF estimated from 99m Tc planar and SPECT/CT phantom imaging, and within this context, to compare the corresponding LSF and lung-absorbed dose values from 99m Tc-MAA patient studies. Additionally, LSFs from pre- and post-therapy imaging were compared. A liver/lung torso phantom filled with 99m Tc to achieve three lung shunt values was scanned by planar and SPECT/CT imaging with repeat acquisitions to assess accuracy and precision. To facilitate processing of patient data, a workflow that relies on SPECT and CT-based auto-contouring to define liver and lung volumes for the LSF calculation was implemented. Planar imaging-based LSF estimates for 40 patients, obtained from their medical records, were retrospectively compared with SPECT/CT imaging-based calculations with attenuation and scatter correction. Additionally, in a subset of 20 patients, the pre-therapy estimates were compared with 90 Y PET/CT-based measurements. In the phantom study, improved accuracy in LSF estimation was achieved using SPECT/CT with attenuation and scatter correction (within 13% of the true value) compared with planar imaging (up to 44% overestimation). The results in patients showed a similar trend with planar imaging significantly overestimating LSF compared to SPECT/CT. There was no correlation between lung shunt estimates and the delay between 99m Tc-MAA administration and scanning, but off-target extra hepatic uptake tended to be more likely in patients with a longer delay. The mean lung absorbed dose predictions for the 28 patients who underwent therapy was 9.3 Gy (range 1.3-29.4) for planar imaging and 3.2 Gy (range 0.4-13.4) for SPECT/CT. For the patients with post-therapy imaging, the mean LSF from 90 Y PET/CT was 1.0%, (range 0.3-2.8). This value was not significantly different from the mean LSF estimate from 99m Tc-MAA SPECT/CT (mean 1.0%, range 0.4-1.6; p = 0.968), but was significantly lower than the mean LSF estimate based on planar imaging (mean 4.1%, range 1.2-15.0; p = 0.0002). The improved accuracy demonstrated by the phantom study, agreement with 90 Y PET/CT in patient studies, and the practicality of using auto-contouring for liver/lung definition suggests that 99m Tc-MAA SPECT/CT with scatter and attenuation corrections should be used for lung shunt estimation prior to radioembolization.

Evaluation of novel computerized tomography scoring systems in human traumatic brain injury: An observational, multicenter study

PubMed Central

Kivisaari, Riku; Svensson, Mikael; Skrifvars, Markus B.

2017-01-01

Background Traumatic brain injury (TBI) is a major contributor to morbidity and mortality. Computerized tomography (CT) scanning of the brain is essential for diagnostic screening of intracranial injuries in need of neurosurgical intervention, but may also provide information concerning patient prognosis and enable baseline risk stratification in clinical trials. Novel CT scoring systems have been developed to improve current prognostic models, including the Stockholm and Helsinki CT scores, but so far have not been extensively validated. The primary aim of this study was to evaluate the Stockholm and Helsinki CT scores for predicting functional outcome, in comparison with the Rotterdam CT score and Marshall CT classification. The secondary aims were to assess which individual components of the CT scores best predict outcome and what additional prognostic value the CT scoring systems contribute to a clinical prognostic model. Methods and findings TBI patients requiring neuro-intensive care and not included in the initial creation of the Stockholm and Helsinki CT scoring systems were retrospectively included from prospectively collected data at the Karolinska University Hospital (n = 720 from 1 January 2005 to 31 December 2014) and Helsinki University Hospital (n = 395 from 1 January 2013 to 31 December 2014), totaling 1,115 patients. The Marshall CT classification and the Rotterdam, Stockholm, and Helsinki CT scores were assessed using the admission CT scans. Known outcome predictors at admission were acquired (age, pupil responsiveness, admission Glasgow Coma Scale, glucose level, and hemoglobin level) and used in univariate, and multivariable, regression models to predict long-term functional outcome (dichotomizations of the Glasgow Outcome Scale [GOS]). In total, 478 patients (43%) had an unfavorable outcome (GOS 1–3). In the combined cohort, overall prognostic performance was more accurate for the Stockholm CT score (Nagelkerke’s pseudo-R2 range 0.24–0.28) and the Helsinki CT score (0.18–0.22) than for the Rotterdam CT score (0.13–0.15) and Marshall CT classification (0.03–0.05). Moreover, the Stockholm and Helsinki CT scores added the most independent prognostic value in the presence of other known clinical outcome predictors in TBI (6% and 4%, respectively). The aggregate traumatic subarachnoid hemorrhage (tSAH) component of the Stockholm CT score was the strongest predictor of unfavorable outcome. The main limitations were the retrospective nature of the study, missing patient information, and the varying follow-up time between the centers. Conclusions The Stockholm and Helsinki CT scores provide more information on the damage sustained, and give a more accurate outcome prediction, than earlier classification systems. The strong independent predictive value of tSAH may reflect an underrated component of TBI pathophysiology. A change to these newer CT scoring systems may be warranted. PMID:28771476

Development of a semi-automated combined PET and CT lung lesion segmentation framework

NASA Astrophysics Data System (ADS)

Rossi, Farli; Mokri, Siti Salasiah; Rahni, Ashrani Aizzuddin Abd.

2017-03-01

Segmentation is one of the most important steps in automated medical diagnosis applications, which affects the accuracy of the overall system. In this paper, we propose a semi-automated segmentation method for extracting lung lesions from thoracic PET/CT images by combining low level processing and active contour techniques. The lesions are first segmented in PET images which are first converted to standardised uptake values (SUVs). The segmented PET images then serve as an initial contour for subsequent active contour segmentation of corresponding CT images. To evaluate its accuracy, the Jaccard Index (JI) was used as a measure of the accuracy of the segmented lesion compared to alternative segmentations from the QIN lung CT segmentation challenge, which is possible by registering the whole body PET/CT images to the corresponding thoracic CT images. The results show that our proposed technique has acceptable accuracy in lung lesion segmentation with JI values of around 0.8, especially when considering the variability of the alternative segmentations.

Differential diagnosis between benign and malignant pleural effusion with dual-energy spectral CT

PubMed Central

Zhang, Xirong; Duan, Haifeng; Yu, Yong; Ma, Chunling; Ren, Zhanli; Lei, Yuxin

2018-01-01

Purpose To investigate the value of spectral CT in the differential diagnosis of benign from malignant pleural effusion. Method and materials 14 patients with benign pleural effusion and 15 patients with malignant pleural effusion underwent non-contrast spectral CT imaging. These patients were later verified by the combination of disease history, clinical signs and other information with the consensus of surgeons and radiologists. Various Spectral CT image parameters measured for the effusion were as follows: CT numbers of the polychromatic 140kVp images, monochromatic images at 40keV and 100keV, the material density contents from the water, fat and blood-based material decomposition images, the effective atomic number and the spectral curve slope. These values were statistically compared with t test and logistic regression analysis between benign and malignant pleural effusion. Results The CT value of benign and malignant pleural effusion in the polychromatic 140kVp images showed no differences (12.61±3.39HU vs. 14.71±5.03HU) (P>0.05), however, they were statistically different on the monochromatic images at 40keV (43.15±3.79 vs. 39.42±2.60, p = 0.005) and 100keV (9.11±1.38 vs. 6.52±2.04, p<0.001). There was difference in the effective atomic number value between the benign (7.87±0.08) and malignant pleural effusion (7.90±0.02) (P = 0.02). Using 6.32HU as the threshold for CT value measurement at 100keV, one could obtain sensitivity of 100% and specificity of 66.7% with area-under-curve of 0.843 for differentiating benign from malignant effusion. In addition, age and disease history were potential confounding factors for differentiating malignant pleural effusion from benign, since the older age (61.13±12.51 year-old vs48.57±12.33 year-old) as well as longer disease history (70.00±49.28 day vs.28.36±21.64 day) were more easily to be found in the malignant pleural effusion group than those in the benign pleural effusion group. By combining above five factors, one could obtain sensitivity of 100% and specificity of 71.4% with area-under-curve of 0.933 for differentiating benign from malignant effusion. Conclusion The CT value measurement at both high and low energy levels and the effective atomic number obtained in a single spectral CT scan can assist the differential diagnosis of benign from malignant pleural effusion.Combining them with patient age and disease history can further improve diagnostic performance. Clinical relevance/Application Clinical findings and Spectral CT imaging can provide significant evidences about the nature of pleural effusion. PMID:29641601

Differential diagnosis between benign and malignant pleural effusion with dual-energy spectral CT.

PubMed

Zhang, Xirong; Duan, Haifeng; Yu, Yong; Ma, Chunling; Ren, Zhanli; Lei, Yuxin; He, Taiping; Zhang, Ming

2018-01-01

To investigate the value of spectral CT in the differential diagnosis of benign from malignant pleural effusion. 14 patients with benign pleural effusion and 15 patients with malignant pleural effusion underwent non-contrast spectral CT imaging. These patients were later verified by the combination of disease history, clinical signs and other information with the consensus of surgeons and radiologists. Various Spectral CT image parameters measured for the effusion were as follows: CT numbers of the polychromatic 140kVp images, monochromatic images at 40keV and 100keV, the material density contents from the water, fat and blood-based material decomposition images, the effective atomic number and the spectral curve slope. These values were statistically compared with t test and logistic regression analysis between benign and malignant pleural effusion. The CT value of benign and malignant pleural effusion in the polychromatic 140kVp images showed no differences (12.61±3.39HU vs. 14.71±5.03HU) (P>0.05), however, they were statistically different on the monochromatic images at 40keV (43.15±3.79 vs. 39.42±2.60, p = 0.005) and 100keV (9.11±1.38 vs. 6.52±2.04, p<0.001). There was difference in the effective atomic number value between the benign (7.87±0.08) and malignant pleural effusion (7.90±0.02) (P = 0.02). Using 6.32HU as the threshold for CT value measurement at 100keV, one could obtain sensitivity of 100% and specificity of 66.7% with area-under-curve of 0.843 for differentiating benign from malignant effusion. In addition, age and disease history were potential confounding factors for differentiating malignant pleural effusion from benign, since the older age (61.13±12.51 year-old vs48.57±12.33 year-old) as well as longer disease history (70.00±49.28 day vs.28.36±21.64 day) were more easily to be found in the malignant pleural effusion group than those in the benign pleural effusion group. By combining above five factors, one could obtain sensitivity of 100% and specificity of 71.4% with area-under-curve of 0.933 for differentiating benign from malignant effusion. The CT value measurement at both high and low energy levels and the effective atomic number obtained in a single spectral CT scan can assist the differential diagnosis of benign from malignant pleural effusion.Combining them with patient age and disease history can further improve diagnostic performance. Clinical findings and Spectral CT imaging can provide significant evidences about the nature of pleural effusion.

Accuracy of low dose CT in the diagnosis of appendicitis in childhood and comparison with USG and standard dose CT.

PubMed

Yi, Dae Yong; Lee, Kyung Hoon; Park, Sung Bin; Kim, Jee Taek; Lee, Na Mi; Kim, Hyery; Yun, Sin Weon; Chae, Soo Ahn; Lim, In Seok

Computed tomography should be performed after careful consideration due to radiation hazard, which is why interest in low dose CT has increased recently in acute appendicitis. Previous studies have been performed in adult and adolescents populations, but no studies have reported on the efficacy of using low-dose CT in children younger than 10 years. Patients (n=475) younger than 10 years who were examined for acute appendicitis were recruited. Subjects were divided into three groups according to the examinations performed: low-dose CT, ultrasonography, and standard-dose CT. Subjects were categorized according to age and body mass index (BMI). Low-dose CT was a contributive tool in diagnosing appendicitis, and it was an adequate method, when compared with ultrasonography and standard-dose CT in terms of sensitivity (95.5% vs. 95.0% and 94.5%, p=0.794), specificity (94.9% vs. 80.0% and 98.8%, p=0.024), positive-predictive value (96.4% vs. 92.7% and 97.2%, p=0.019), and negative-predictive value (93.7% vs. 85.7% and 91.3%, p=0.890). Low-dose CT accurately diagnosed patients with a perforated appendix. Acute appendicitis was effectively diagnosed using low-dose CT in both early and middle childhood. BMI did not influence the accuracy of detecting acute appendicitis on low-dose CT. Low-dose CT is effective and accurate for diagnosing acute appendicitis in childhood, as well as in adolescents and young adults. Additionally, low-dose CT was relatively accurate, irrespective of age or BMI, for detecting acute appendicitis. Therefore, low-dose CT is recommended for assessing children with suspected acute appendicitis. Copyright © 2017. Published by Elsevier Editora Ltda.

Correlations between symptoms, nasal endoscopy, and in-office computed tomography in post-surgical chronic rhinosinusitis patients.

PubMed

Ryan, William R; Ramachandra, Tara; Hwang, Peter H

2011-03-01

To determine correlations between symptoms, nasal endoscopy findings, and computed tomography (CT) scan findings in post-surgical chronic rhinosinusitis (CRS) patients. Cross-sectional. A total of 51 CRS patients who had undergone endoscopic sinus surgery (ESS) completed symptom questionnaires, underwent endoscopy, and received an in-office sinus CT scan during one clinic visit. For metrics, we used the Sinonasal Outcomes Test-20 (SNOT-20) questionnaire, visual analog symptom scale (VAS), Lund-Kennedy endoscopy scoring scale, and Lund-MacKay (LM) CT scoring scale. We determined Pearson correlation coefficients, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) between scores for symptoms, endoscopy, and CT. The SNOT-20 score and most VAS symptoms had poor correlation coefficients with both endoscopy and CT scores (0.03-0.24). Nasal drainage of pus, nasal congestion, and impaired sense of smell had moderate correlation coefficients with endoscopy and CT (0.24-0.42). Endoscopy had a strong correlation coefficient with CT (0.76). Drainage, edema, and polyps had strong correlation coefficients with CT (0.80, 0.69, and 0.49, respectively). Endoscopy had a PPV of 92.5% and NPV of 45.5% for detecting an abnormal sinus CT (LM score ≥1). In post-ESS CRS patients, most symptoms do not correlate well with either endoscopy or CT findings. Endoscopy and CT scores correlate well. Abnormal endoscopy findings have the ability to confidently rule in the presence of CT opacification, thus validating the importance of endoscopy in clinical decision making. However, a normal endoscopy cannot assure a normal CT. Thus, symptoms, endoscopy, and CT are complementary in the evaluation of the post-ESS CRS patient. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc., Rhinological, and Otological Society, Inc.

Technical Note: Quantitative accuracy evaluation for spectral images from a detector-based spectral CT scanner using an iodine phantom.

PubMed

Duan, Xinhui; Arbique, Gary; Guild, Jeffrey; Xi, Yin; Anderson, Jon

2018-05-01

The purpose of this study was to evaluate the quantitative accuracy of spectral images from a detector-based spectral CT scanner using a phantom with iodine-loaded inserts. A 40-cm long-body phantom with seven iodine inserts (2-20 mg/ml of iodine) was used in the study. The inserts could be placed at 5.5 or 10.5 cm from the phantom axis. The phantom was scanned five times for each insert configuration using 120 kVp tube voltage. A set of iodine, virtual noncontrast, effective atomic number, and virtual monoenergetic spectral CT images were generated and measurements were made for all the iodine rods. Measured values were compared with reference values calculated from the chemical composition information provided by the phantom manufacturer. Radiation dose from the spectral CT was compared to a conventional CT using a CTDI (32 cm) phantom. Good agreement between measurements and reference values was achieved for all types of spectral images. The differences ranged from -0.46 to 0.1 mg/ml for iodine concentration, -9.95 to 6.41 HU for virtual noncontrast images, 0.12 to 0.35 for effective Z images, and -17.7 to 55.7 HU for virtual monoenergetic images. For a similar CTDIvol, image noise from the conventional CT was 10% lower than the spectral CT. The detector-based spectral CT can achieve accurate spectral measurements on iodine concentration, virtual non-contrast images, effective atomic numbers, and virtual monoenergetic images. © 2018 American Association of Physicists in Medicine.

Black Hole Sign: Novel Imaging Marker That Predicts Hematoma Growth in Patients With Intracerebral Hemorrhage.

PubMed

Li, Qi; Zhang, Gang; Xiong, Xin; Wang, Xing-Chen; Yang, Wen-Song; Li, Ke-Wei; Wei, Xiao; Xie, Peng

2016-07-01

Early hematoma growth is a devastating neurological complication after intracerebral hemorrhage. We aim to report and evaluate the usefulness of computed tomography (CT) black hole sign in predicting hematoma growth in patients with intracerebral hemorrhage. Patients with intracerebral hemorrhage were screened for the presence of CT black hole sign on admission head CT performed within 6 hours after onset of symptoms. The black hole sign was defined as hypoattenuatting area encapsulated within the hyperattenuating hematoma with a clearly defined border. The sensitivity, specificity, and positive and negative predictive values of CT black hole sign in predicting hematoma expansion were calculated. Logistic regression analyses were used to assess the presence of the black hole sign and early hematoma growth. A total of 206 patients were enrolled. Black hole sign was found in 30 (14.6%) of 206 patients on the baseline CT scan. The black hole sign was more common in patients with hematoma growth (31.9%) than those without hematoma growth (5.8%; P<0.001). The sensitivity, specificity, positive predictive value, and negative predictive value of back hole sign in predicting early hematoma growth were 31.9%, 94.1%, 73.3%, and 73.2%, respectively. The time-to-admission CT scan, baseline hematoma volume, and the presence of black hole sign on admission CT independently predict hematoma growth in multivariate model. The CT black hole sign could be used as a simple and easy-to-use predictor for early hematoma growth in patients with intracerebral hemorrhage. © 2016 American Heart Association, Inc.

Diagnostic performance of multi-slice CT angiography combined with enterography for small bowel obstruction and intestinal ischaemia.

PubMed

He, Bosheng; Gu, Jinhua; Huang, Sheng; Gao, Xuesong; Fan, Jinhe; Sheng, Meihong; Wang, Lin; Gong, Shenchu

2017-02-01

This study was performed to evaluate the diagnostic performance of multi-slice CT angiography combined with enterography in determining the cause and location of obstruction as well as intestinal ischaemia in patients with small bowel obstruction (SBO). This study retrospectively summarized the image data of 57 SBO patients who received both multi-slice CT angiography and enterography examination between December 2012 and May 2013. The CT diagnoses of SBO and intestinal ischaemia were correlated with the findings at surgery or digital subtraction angiography, which were set as standard references. Multi-slice CT angiography and enterography indicated that the cause of SBO in three patients was misjudged, suggesting a diagnostic accuracy of 94.7%. In one patient the level of obstruction was incorrect, demonstrating a diagnostic accuracy of 98.2%. Based on the results of the receiver operating characteristic (ROC) curve analysis, the diagnostic criterion for ischaemic SBO was at least two of the four CT signs (circumferential bowel wall thickening, reduced enhancement of the intestinal wall, mesenteric oedema and mesenteric vascular engorgement). The criterion yielded a sensitivity of 94.4%, a specificity of 92.3%, a positive predicted value of 85.0% and a negative predicted value of 97.3%, and the area under curve (AUC) was 0.92 (95% CI, 0.85-0.99). Multi-slice CT angiography and enterography have high diagnostic value in identifying the cause and site of SBO. In addition, the suggested diagnostic criterion using CT signs is helpful for diagnosing intestinal ischaemia in SBO patients. © 2016 The Royal Australian and New Zealand College of Radiologists.

Is 3-Tesla Gd-EOB-DTPA-Enhanced MRI with Diffusion-Weighted Imaging Superior to 64-Slice Contrast-Enhanced CT for the Diagnosis of Hepatocellular Carcinoma?

PubMed Central

Maiwald, Bettina; Lobsien, Donald; Kahn, Thomas; Stumpp, Patrick

2014-01-01

Objectives To compare 64-slice contrast-enhanced computed tomography (CT) with 3-Tesla magnetic resonance imaging (MRI) using Gd-EOB-DTPA for the diagnosis of hepatocellular carcinoma (HCC) and evaluate the utility of diffusion-weighted imaging (DWI) in this setting. Methods 3-phase-liver-CT was performed in fifty patients (42 male, 8 female) with suspected or proven HCC. The patients were subjected to a 3-Tesla-MRI-examination with Gd-EOB-DTPA and diffusion weighted imaging (DWI) at b-values of 0, 50 and 400 s/mm2. The apparent diffusion coefficient (ADC)-value was determined for each lesion detected in DWI. The histopathological report after resection or biopsy of a lesion served as the gold standard, and a surrogate of follow-up or complementary imaging techniques in combination with clinical and paraclinical parameters was used in unresected lesions. Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were evaluated for each technique. Results MRI detected slightly more lesions that were considered suspicious for HCC per patient compared to CT (2.7 versus 2.3, respectively). ADC-measurements in HCC showed notably heterogeneous values with a median of 1.2±0.5×10−3 mm2/s (range from 0.07±0.1 to 3.0±0.1×10−3 mm2/s). MRI showed similar diagnostic accuracy, sensitivity, and positive and negative predictive values compared to CT (AUC 0.837, sensitivity 92%, PPV 80% and NPV 90% for MRI vs. AUC 0.798, sensitivity 85%, PPV 79% and NPV 82% for CT; not significant). Specificity was 75% for both techniques. Conclusions Our study did not show a statistically significant difference in detection in detection of HCC between MRI and CT. Gd-EOB-DTPA-enhanced MRI tended to detect more lesions per patient compared to contrast-enhanced CT; therefore, we would recommend this modality as the first-choice imaging method for the detection of HCC and therapeutic decisions. However, contrast-enhanced CT was not inferior in our study, so that it can be a useful image modality for follow-up examinations. PMID:25375778

Very low-dose (0.15 mGy) chest CT protocols using the COPDGene 2 test object and a third-generation dual-source CT scanner with corresponding third-generation iterative reconstruction software.

PubMed

Newell, John D; Fuld, Matthew K; Allmendinger, Thomas; Sieren, Jered P; Chan, Kung-Sik; Guo, Junfeng; Hoffman, Eric A

2015-01-01

The purpose of this study was to evaluate the impact of ultralow radiation dose single-energy computed tomographic (CT) acquisitions with Sn prefiltration and third-generation iterative reconstruction on density-based quantitative measures of growing interest in phenotyping pulmonary disease. The effects of both decreasing dose and different body habitus on the accuracy of the mean CT attenuation measurements and the level of image noise (SD) were evaluated using the COPDGene 2 test object, containing 8 different materials of interest ranging from air to acrylic and including various density foams. A third-generation dual-source multidetector CT scanner (Siemens SOMATOM FORCE; Siemens Healthcare AG, Erlangen, Germany) running advanced modeled iterative reconstruction (ADMIRE) software (Siemens Healthcare AG) was used.We used normal and very large body habitus rings at dose levels varying from 1.5 to 0.15 mGy using a spectral-shaped (0.6-mm Sn) tube output of 100 kV(p). Three CT scans were obtained at each dose level using both rings. Regions of interest for each material in the test object scans were automatically extracted. The Hounsfield unit values of each material using weighted filtered back projection (WFBP) at 1.5 mGy was used as the reference value to evaluate shifts in CT attenuation at lower dose levels using either WFBP or ADMIRE. Statistical analysis included basic statistics, Welch t tests, multivariable covariant model using the F test to assess the significance of the explanatory (independent) variables on the response (dependent) variable, and CT mean attenuation, in the multivariable covariant model including reconstruction method. Multivariable regression analysis of the mean CT attenuation values showed a significant difference with decreasing dose between ADMIRE and WFBP. The ADMIRE has reduced noise and more stable CT attenuation compared with WFBP. There was a strong effect on the mean CT attenuation values of the scanned materials for ring size (P < 0.0001) and dose level (P < 0.0001). The number of voxels in the region of interest for the particular material studied did not demonstrate a significant effect (P > 0.05). The SD was lower with ADMIRE compared with WFBP at all dose levels and ring sizes (P < 0.05). The third-generation dual-source CT scanners using third-generation iterative reconstruction methods can acquire accurate quantitative CT images with acceptable image noise at very low-dose levels (0.15 mGy). This opens up new diagnostic and research opportunities in CT phenotyping of the lung for developing new treatments and increased understanding of pulmonary disease.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korhonen, Juha, E-mail: juha.p.korhonen@hus.fi; Kapanen, Mika; Department of Oncology, Helsinki University Central Hospital, POB-180, 00029 HUS

Purpose: The lack of electron density information in magnetic resonance images (MRI) poses a major challenge for MRI-based radiotherapy treatment planning (RTP). In this study the authors convert MRI intensity values into Hounsfield units (HUs) in the male pelvis and thus enable accurate MRI-based RTP for prostate cancer patients with varying tissue anatomy and body fat contents. Methods: T{sub 1}/T{sub 2}*-weighted MRI intensity values and standard computed tomography (CT) image HUs in the male pelvis were analyzed using image data of 10 prostate cancer patients. The collected data were utilized to generate a dual model HU conversion technique from MRImore » intensity values of the single image set separately within and outside of contoured pelvic bones. Within the bone segment local MRI intensity values were converted to HUs by applying a second-order polynomial model. This model was tuned for each patient by two patient-specific adjustments: MR signal normalization to correct shifts in absolute intensity level and application of a cutoff value to accurately represent low density bony tissue HUs. For soft tissues, such as fat and muscle, located outside of the bone contours, a threshold-based segmentation method without requirements for any patient-specific adjustments was introduced to convert MRI intensity values into HUs. The dual model HU conversion technique was implemented by constructing pseudo-CT images for 10 other prostate cancer patients. The feasibility of these images for RTP was evaluated by comparing HUs in the generated pseudo-CT images with those in standard CT images, and by determining deviations in MRI-based dose distributions compared to those in CT images with 7-field intensity modulated radiation therapy (IMRT) with the anisotropic analytical algorithm and 360° volumetric-modulated arc therapy (VMAT) with the Voxel Monte Carlo algorithm. Results: The average HU differences between the constructed pseudo-CT images and standard CT images of each test patient ranged from −2 to 5 HUs and from 22 to 78 HUs in soft and bony tissues, respectively. The average local absolute value differences were 11 HUs in soft tissues and 99 HUs in bones. The planning target volume doses (volumes 95%, 50%, 5%) in the pseudo-CT images were within 0.8% compared to those in CT images in all of the 20 treatment plans. The average deviation was 0.3%. With all the test patients over 94% (IMRT) and 92% (VMAT) of dose points within body (lower than 10% of maximum dose suppressed) passed the 1 mm and 1% 2D gamma index criterion. The statistical tests (t- and F-tests) showed significantly improved (p ≤ 0.05) HU and dose calculation accuracies with the soft tissue conversion method instead of homogeneous representation of these tissues in MRI-based RTP images. Conclusions: This study indicates that it is possible to construct high quality pseudo-CT images by converting the intensity values of a single MRI series into HUs in the male pelvis, and to use these images for accurate MRI-based prostate RTP dose calculations.« less

The implications of condensed tannins on the nutritive value of temperate forages fed to ruminants.

PubMed

Barry, T N; McNabb, W C

1999-04-01

New methodology for measuring forage condensed tannin (CT) content is described and the effects of CT upon forage feeding and nutritive value for ruminant animals are reviewed. CT react with forage proteins in a pH-reversible manner, with reactivity determined by the concentration, structure and molecular mass of the CT. Increasing concentrations of CT in Lotus corniculatus and Lotus pedunculatus reduce the rates of solubilization and degradation of fraction 1 leaf protein in the rumen and increase duodenal non-NH3 N flow. Action of medium concentrations of total CT in Lotus corniculatus (30-40 g/kg DM) increased the absorption of essential amino acids from the small intestine and increased wool growth, milk secretion and reproductive rate in grazing sheep without affecting voluntary feed intake, thus improving the efficiency of food conversion. High concentrations of CT in Lotus pedunculatus (75-100 g/kg DM) depressed voluntary feed intake and rumen carbohydrate digestion and depressed rates of body and wool growth in grazing sheep. The minimum concentration of CT to prevent rumen frothy bloat in cattle is defined as 5 g/kg DM and sheep grazing CT-containing legumes were shown to better tolerate internal parasite infections than sheep grazing non CT-containing forages. It was concluded that defined concentrations of forage CT can be used to increase the efficiencies of protein digestion and animal productivity in forage-fed ruminants and to develop more ecologically sustainable systems of controlling some diseases under grazing.

SU-G-206-08: How Should Focal Spot Be Chosen for Optimized CT Imaging with Dose Modulation?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bache, S; Liu, X; Rong, J

Purpose: To choose the preferred focal spot for achieving optimized CT image quality with balanced tube heating considerations. Methods: An anthropomorphic pelvic phantom was scanned using a GE Discovery CT750 HD at 120 and 140kVp, 0.8s rotation time, and pitch of 0.984. “Smart mA” was enabled to simulate a routine abdomen–pelvis CT scan. Permissible mA values at 120 and 140 kVp were obtained from the Serial Load Rating table (for mimicking a busy CT clinical operation) in the scanner Technical Reference Manual. At each kVp station and two Noise Index levels, the mA Upper Limit was set above/below the permissiblemore » mA values. Scanned mA values and focal spot (FS) used were obtained from the DICOM header of each image, and the FS-mA relationship was analyzed. For visual confirmation beyond recorded FS information, a CatPhan with a fat-ring attached for mimicking patient size/shape was scanned at 120kVp. A group of radiologists/physicists compared a pair of CatPhan images qualitatively. Lastly, a number of patient cases were evaluated to confirm the FS-mA relationship. Results: When preset Upper Limit values were above the permissible mA values, the Large FS (labeled 1.2) was used in scans, even if the maximum scanned mA values were much lower than the permissible values at both 120 and 140 kVp. Otherwise the Small FS (labeled 0.7) was used. Visual evaluation of the high contrast module of CatPhan and additional analysis of patient cases further confirmed that the preset Upper Limit determines which focal spot is to be used, not the actual maximum mA value to be scanned. Conclusion: Specific FS can be selected by setting up appropriate mA Upper Limit in a protocol. CT protocols could be optimized by selecting appropriate FS for improving patient image quality, especially benefiting the small size and pediatric patients.« less

Estimation of test characteristics of real-time PCR and bacterial culture for diagnosis of subclinical intramammary infections with Streptococcus agalactiae in Danish dairy cattle in 2012 using latent class analysis.

PubMed

Mahmmod, Yasser S; Toft, Nils; Katholm, Jørgen; Grønbæk, Carsten; Klaas, Ilka C

2013-05-01

The misdiagnosis of intramammary infections (IMI) with Streptococcus agalactiae (S. agalactiae) could lead farmers to treat or cull animals unnecessarily. The objective of this field study was to estimate the sensitivity (Se) and specificity (Sp) of real-time PCR at different cut-offs for cycle threshold (Ct) values against bacterial culture (BC) for diagnosis of S. agalactiae IMI using latent class analysis to avoid the assumption of a perfect reference test. A total of 614 dairy cows were randomly selected from 6 herds with bulk tank PCR Ct value ≤ 39 for S. agalactiae and S. aureus. At milk recording, 2456 quarter milk samples were taken aseptically for BC and the routinely taken cow level milk samples were analyzed by PCR. Results showed that 53 cows (8.6%) were positive for S. agalactiae IMI by BC. Sensitivity of PCR at cut-offs; ≤ 39, ≤ 37, ≤ 34, and ≤ 32, was 96.2%, 91.9%, 87.2% and 73.9%, while Se of BC was 25.7%, 29.9%, 59.9% and 72.1%. Specificity of PCR at cut-offs; ≤ 39, ≤ 37, ≤ 34, and ≤ 32, was 96.8%, 96.9%, 96.7%, and 97.22%, while Sp of BC was 99.7%, 99.5%, 99.2%, and 98.9%. The estimated prevalence of S. agalactiae IMI by PCR was higher than the apparent prevalence at the tested cut-offs, indicating under estimation of S. agalactiae IMI in the examined dairy cows. In conclusion, Se of PCR is always higher than Se of BC at all tested cut-offs. The lower cut-off, the more comparable becomes Se of PCR and Se of BC. The changes in Se in both PCR and BC at different Ct-value cut-offs may indicate a change in the definition of the latent infection. The similar Se of both tests at cut-off ≤ 32 may indicate high concentrations of S. agalactiae viable cells, representing a cow truly/heavily infected with S. agalactiae and thus easier to detect with BC. At cut-off ≤ 39 the latent definition of infection may reflect a more general condition of cows being positive for S. agalactiae. Our findings indicate that PCR Ct-value cut-offs should be chosen according to the underlying latent infection definition of interest. Latent class analysis proposes a useful alternative to classic test evaluation of diagnostic tests used for detection of S. agalactiae IMI in milk. Copyright © 2012 Elsevier B.V. All rights reserved.

A COMPARISON OF THREE ASSAY PROCEDURES FOR DETERMINING CHLORINE INACTIVATION OF WATERBORNE PATHOGENIC BACTERIA

EPA Science Inventory

One criterion on which chlorine treatment of water may be based is the concentration (C) in mg/l multiplied by the time (t) in min of exposure or Ct values. We compared different Ct values on waterborne pathogenic bacteria by cultural assay for viability and 2 assays that mea...

High energy x-ray phase contrast CT using glancing-angle grating interferometers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarapata, A., E-mail: adrian.sarapata@tum.de; Stayman, J. W.; Siewerdsen, J. H.

Purpose: The authors present initial progress toward a clinically compatible x-ray phase contrast CT system, using glancing-angle x-ray grating interferometry to provide high contrast soft tissue images at estimated by computer simulation dose levels comparable to conventional absorption based CT. Methods: DPC-CT scans of a joint phantom and of soft tissues were performed in order to answer several important questions from a clinical setup point of view. A comparison between high and low fringe visibility systems is presented. The standard phase stepping method was compared with sliding window interlaced scanning. Using estimated dose values obtained with a Monte-Carlo code themore » authors studied the dependence of the phase image contrast on exposure time and dose. Results: Using a glancing angle interferometer at high x-ray energy (∼45 keV mean value) in combination with a conventional x-ray tube the authors achieved fringe visibility values of nearly 50%, never reported before. High fringe visibility is shown to be an indispensable parameter for a potential clinical scanner. Sliding window interlaced scanning proved to have higher SNRs and CNRs in a region of interest and to also be a crucial part of a low dose CT system. DPC-CT images of a soft tissue phantom at exposures in the range typical for absorption based CT of musculoskeletal extremities were obtained. Assuming a human knee as the CT target, good soft tissue phase contrast could be obtained at an estimated absorbed dose level around 8 mGy, similar to conventional CT. Conclusions: DPC-CT with glancing-angle interferometers provides improved soft tissue contrast over absorption CT even at clinically compatible dose levels (estimated by a Monte-Carlo computer simulation). Further steps in image processing, data reconstruction, and spectral matching could make the technique fully clinically compatible. Nevertheless, due to its increased scan time and complexity the technique should be thought of not as replacing, but as complimentary to conventional CT, to be used in specific applications.« less

Computed tomography for occult fractures of the proximal femur, pelvis, and sacrum in clinical practice: single institution, dual-site experience.

PubMed

Mandell, Jacob C; Weaver, Michael J; Khurana, Bharti

2018-06-01

The purpose of this study was to evaluate the diagnostic performance of CT for assessment of occult fractures of the proximal femur, pelvis, and sacrum. A retrospective review was performed on patients who received a CT of the hip or pelvis for suspected occult fracture after negative or equivocal radiographs performed within 24 h. The official radiology report was utilized for the determination of CT findings and calculation of sensitivity and specificity. Surgical reports, MRI reports, and clinical follow-up were used as the standard of reference. Sensitivity and specificity were calculated with 95% confidence intervals. Seventy-four patients received CT of the hip or pelvis for clinical concern for occult fracture after negative or equivocal radiographs. By the reference standard, a total of 40 fractures were present in 25/74 (33.8%) patients, including 35 conservatively treated fractures of the greater trochanter, pelvis, and sacrum, and 5 operatively treated proximal femoral fractures. A total of 14/74 (18.9%) of patients had an MRI within 1 day of CT. MRI identified an operatively treated femoral neck fracture not seen on CT and an operatively treated intertrochanteric fracture, which CT described as a greater trochanteric fracture. There were two false negative conservatively treated pelvic fractures not seen on CT but diagnosed on MRI. On a per-patient basis, CT had an overall sensitivity of 88% (22/25; 95% confidence intervals 69-97%), specificity of 98% (48/49; 95% confidence intervals 89-100%), and negative predictive value of 94%. For the five operative proximal femoral fractures, the sensitivity of CT was 60% (3/5; 95% confidence intervals 15-95%), specificity was 99% (68/69; 95% confidence intervals 92-100%), and negative predictive value was 97%. In the clinical setting of suspected occult fracture, the sensitivity of clinical CT reports for detection of any type of fracture of the proximal femur, pelvis, or sacrum was 88%. For the small number of operatively treated proximal femoral fractures seen in the study, sensitivity of CT was 60% (3/5) and negative predictive value was 97%, although the relatively few patients needing fixation precludes statistical analysis.

Presence of a temperature gradient among genital tract portions and the thermal changes within these portions over the estrous cycle in beef cows.

PubMed

El-Sheikh Ali, Hossam; Kitahara, Go; Tamura, Youji; Kobayashi, Ikuo; Hemmi, Koichiro; Torisu, Shidow; Sameshima, Hiroshi; Horii, Yoichiro; Zaabel, Samy; Kamimura, Shunichi

2013-01-01

The aim of the present study was to describe the temperature of the different portions of the female genital tract and their relation to rectal temperature and to investigate the effect of steroid hormones profiles on these variables over the estrous cycle in cattle. Four nonpregnant Japanese Black cows were investigated daily over two successive estrous cycles using a digital thermometer with a long probe and rounded-end sensor to record the temperature of the rectum (RT), vagina (VT), cervix (CT), uterine body (UBT) and uterine horns (UHT). Blood samples were collected immediately before temperature recording to assay peripheral levels of progesterone (P(4)) and estradiol-17β (E(2)). Moreover, transrectal ultrasonography was carried out after temperature recording to monitor the ovulatory follicle and track ovulation. During the experiment, the ambient temperature and relative humidity were recorded for further calculation of the temperature humidity index (THI). The temperature within the genital tracts in these cows progressively increased towards the uterine horns from the vagina. The VT, CT, UBT and UHTs were significantly higher in association with peripheral P(4) concentrations greater than 4 ng/ml (mid-luteal phase) when compared with lower peripheral P(4) concentrations. The VT was more significantly (P<0.01) correlated to the CT, UBT and UHTs than RT. In conclusion, a temperature gradient was present among the vagina, cervix and uterus over the estrous cycle, and changes in peripheral P(4) concentrations were associated with the thermal variations within these portions. The VT could be more beneficial than RT in monitoring temperature of deeper portions of the female genital tract in bovine.

Presence of a Temperature Gradient Among Genital Tract Portions and the Thermal Changes Within These Portions Over the Estrous Cycle in Beef Cows

PubMed Central

EL-SHEIKH ALI, Hossam; KITAHARA, Go; TAMURA, Youji; KOBAYASHI, Ikuo; HEMMI, Koichiro; TORISU, Shidow; SAMESHIMA, Hiroshi; HORII, Yoichiro; ZAABEL, Samy; KAMIMURA, Shunichi

2012-01-01

Abstract The aim of the present study was to describe the temperature of the different portions of the female genital tract and their relation to rectal temperature and to investigate the effect of steroid hormones profiles on these variables over the estrous cycle in cattle. Four nonpregnant Japanese Black cows were investigated daily over two successive estrous cycles using a digital thermometer with a long probe and rounded-end sensor to record the temperature of the rectum (RT), vagina (VT), cervix (CT), uterine body (UBT) and uterine horns (UHT). Blood samples were collected immediately before temperature recording to assay peripheral levels of progesterone (P4) and estradiol-17β (E2). Moreover, transrectal ultrasonography was carried out after temperature recording to monitor the ovulatory follicle and track ovulation. During the experiment, the ambient temperature and relative humidity were recorded for further calculation of the temperature humidity index (THI). The temperature within the genital tracts in these cows progressively increased towards the uterine horns from the vagina. The VT, CT, UBT and UHTs were significantly higher in association with peripheral P4 concentrations greater than 4 ng/ml (mid-luteal phase) when compared with lower peripheral P4 concentrations. The VT was more significantly (P<0.01) correlated to the CT, UBT and UHTs than RT. In conclusion, a temperature gradient was present among the vagina, cervix and uterus over the estrous cycle, and changes in peripheral P4 concentrations were associated with the thermal variations within these portions. The VT could be more beneficial than RT in monitoring temperature of deeper portions of the female genital tract in bovine. PMID:23095515

Variability of Burkholderia pseudomallei Strain Sensitivities to Chlorine Disinfection▿

PubMed Central

O'Connell, Heather A.; Rose, Laura J.; Shams, Alicia; Bradley, Meranda; Arduino, Matthew J.; Rice, Eugene W.

2009-01-01

Burkholderia pseudomallei is a select agent and the causative agent of melioidosis. Variations in previously reported chlorine and monochloramine concentration time (Ct) values for disinfection of this organism make decisions regarding the appropriate levels of chlorine in water treatment systems difficult. This study identified the variation in Ct values for 2-, 3-, and 4-log10 reductions of eight environmental and clinical isolates of B. pseudomallei in phosphate-buffered water. The greatest calculated Ct values for a 4-log10 inactivation were 7.8 mg·min/liter for free available chlorine (FAC) at pH 8 and 5°C and 550 mg·min/liter for monochloramine at pH 8 and 5°C. Ionic strength of test solutions, culture hold times in water, and cell washing were ruled out as sources of the differences in prior observations. Tolerance to FAC was correlated with the relative amount of extracellular material produced by each isolate. Solid-phase cytometry analysis using an esterase-cleaved fluorochrome assay detected a 2-log10-higher level of organisms based upon metabolic activity than did culture, which in some cases increased Ct values by fivefold. Despite strain-to-strain variations in Ct values of 17-fold for FAC and 2.5-fold for monochloramine, standard FAC disinfection practices utilized in the United States should disinfect planktonic populations of these B. pseudomallei strains by 4 orders of magnitude in less than 10 min at the tested temperatures and pH levels. PMID:19542324

Five months' follow-up of patients with and without iodine-positive lymph node metastases of thyroid carcinoma as disclosed by (131)I-SPECT/CT at the first radioablation.

PubMed

Schmidt, Daniela; Linke, Rainer; Uder, Michael; Kuwert, Torsten

2010-04-01

In differentiated thyroid carcinoma (DTC), (131)I-SPECT/CT is more accurate in identifying radioiodine-positive lymph node metastases (LNM) than planar whole-body scans (WBS). The purpose of this study was to investigate the value of (131)I-SPECT/CT performed at the first radioablation to predict the occurrence and/or persistence of cervical radioiodine-positive LNM 5 months later. The study included 81 DTC patients that had had SPECT/ spiral CT after radioablation of thyroid remnants after thyroidectomy. The patients were re-examined 5 months later using (131)I-WBS performed at TSH stimulation. In addition, SPECT/CT of the neck was performed in patients with iodine-positive cervical foci to distinguish between thyroid remnant and LNM. The outcome variable of the study was the detection or exclusion of iodine-positive cervical LNM. Of 61 patients without a SPECT/CT diagnosis of (131)I-positive LNM at radioablation, 60 had no (131)I-positive LNM at follow-up. In the remaining patient of this group, a new radioiodine-positive LNM was detected. In 17 of 20 patients with a SPECT/CT diagnosis of (131)I-positive LNM (n = 19) or an indeterminate lesion (n = 1) at first radioablation, no (131)I-positive LNM were detected 5 months later. Radioiodine-positive LNM persisted in three patients of this group. (131)I-SPECT/CT has a high negative predictive value with regard to the occurrence of radioiodine-positive cervical LNM 5 months after initial therapy. The majority of iodine-positive LNM diagnosed by SPECT/CT at radioablation disappear within 5 months. These findings motivate further research into the value of (131)I-SPECT/CT of the neck for predicting recurrence and planning surgical reintervention in DTC.

Cross-modality PET/CT and contrast-enhanced CT imaging for pancreatic cancer

PubMed Central

Zhang, Jian; Zuo, Chang-Jing; Jia, Ning-Yang; Wang, Jian-Hua; Hu, Sheng-Ping; Yu, Zhong-Fei; Zheng, Yuan; Zhang, An-Yu; Feng, Xiao-Yuan

2015-01-01

AIM: To explore the diagnostic value of the cross-modality fusion images provided by positron emission tomography/computed tomography (PET/CT) and contrast-enhanced CT (CECT) for pancreatic cancer (PC). METHODS: Data from 70 patients with pancreatic lesions who underwent CECT and PET/CT examinations at our hospital from August 2010 to October 2012 were analyzed. PET/CECT for the cross-modality image fusion was obtained using TureD software. The diagnostic efficiencies of PET/CT, CECT and PET/CECT were calculated and compared with each other using a χ2 test. P < 0.05 was considered to indicate statistical significance. RESULTS: Of the total 70 patients, 50 had PC and 20 had benign lesions. The differences in the sensitivity, negative predictive value (NPV), and accuracy between CECT and PET/CECT in detecting PC were statistically significant (P < 0.05 for each). In 15 of the 31 patients with PC who underwent a surgical operation, peripancreatic vessel invasion was verified. The differences in the sensitivity, positive predictive value, NPV, and accuracy of CECT vs PET/CT and PET/CECT vs PET/CT in diagnosing peripancreatic vessel invasion were statistically significant (P < 0.05 for each). In 19 of the 31 patients with PC who underwent a surgical operation, regional lymph node metastasis was verified by postsurgical histology. There was no statistically significant difference among the three methods in detecting regional lymph node metastasis (P > 0.05 for each). In 17 of the 50 patients with PC confirmed by histology or clinical follow-up, distant metastasis was confirmed. The differences in the sensitivity and NPV between CECT and PET/CECT in detecting distant metastasis were statistically significant (P < 0.05 for each). CONCLUSION: Cross-modality image fusion of PET/CT and CECT is a convenient and effective method that can be used to diagnose and stage PC, compensating for the defects of PET/CT and CECT when they are conducted individually. PMID:25780297

Effect of slice thickness on image noise and diagnostic content of single-source-dual energy computed tomography

NASA Astrophysics Data System (ADS)

Alshipli, Marwan; Kabir, Norlaili A.

2017-05-01

Computed tomography (CT) employs X-ray radiation to create cross-sectional images. Dual-energy CT acquisition includes the images acquired from an alternating voltage of X-ray tube: a low- and a high-peak kilovoltage. The main objective of this study is to determine the best slice thickness that reduces image noise with adequate diagnostic information using dual energy CT head protocol. The study used the ImageJ software and statistical analyses to aid the medical image analysis of dual-energy CT. In this study, ImageJ software and F-test were utilised as the combination methods to analyse DICOM CT images. They were used to investigate the effect of slice thickness on noise and visibility in dual-energy CT head protocol images. Catphan-600 phantom was scanned at different slice thickness values;.6, 1, 2, 3, 4, 5 and 6 mm, then quantitative analyses were carried out. The DECT operated in helical mode with another fixed scan parameter values. Based on F-test statistical analyses, image noise at 0.6, 1, and 2 mm were significantly different compared to the other images acquired at slice thickness of 3, 4, 5, and 6 mm. However, no significant differences of image noise were observed at 3, 4, 5, and 6 mm. As a result, better diagnostic image value, image visibility, and lower image noise in dual-energy CT head protocol was observed at a slice thickness of 3 mm.

Meta-analysis reveals PTPN22 1858C/T polymorphism confers susceptibility to rheumatoid arthritis in Caucasian but not in Asian population.

PubMed

Nabi, Gowher; Akhter, Naseem; Wahid, Mohd; Bhatia, Kanchan; Mandal, Raju Kumar; Dar, Sajad Ahmad; Jawed, Arshad; Haque, Shafiul

2016-01-01

The PTPN22 1858C/T polymorphism is associated with rheumatoid arthritis (RA). However, reports from the Asian populations are conflicting in nature and lacks consensus. The aim of our study was to evaluate the association between the PTPN22 1858C/T polymorphism and RA in Asian and Caucasian subjects by carrying out a meta-analysis of Asian and Caucasian data. A total of 27 205 RA cases and 27 677 controls were considered in the present meta-analysis involving eight Asian and 35 Caucasian studies. The pooled odds ratios (ORs) were performed for the allele, dominant, and recessive genetic model. No statistically significant association was found between the PTPN22 1858C/T polymorphism and risk of RA in Asian population (allele genetic model: OR = 1.217, 95% confidence interval (CI) = 0.99-1.496, p value 0.061; dominant genetic model: OR = 1.238, 95% CI = 0.982-1.562, p value 0.071; recessive genetic model: OR = 1.964, 95% CI = 0.678-5.693, p value 0.213). A significant association with risk of RA in Caucasian population suggesting that T-- allele does confer susceptibility to RA in this subgroup was observed (allele genetic model: OR = 1.638, 95% CI = 1.574-1.705, p value < 0.0001; dominant genetic model: OR = 1.67, 95% CI = 1.598-1.745, p value < 0.0001; recessive genetic model: OR = 2.65, 95% CI = 2.273-3.089, p value < 0.0001). The PTPN22 1858C/T polymorphism is not associated with RA risk in Asian populations. However, our meta-analysis confirms that the PTPN22 1858C/T polymorphism is associated with RA susceptibility in Caucasians.

Handling Density Conversion in TPS.

PubMed

Isobe, Tomonori; Mori, Yutaro; Takei, Hideyuki; Sato, Eisuke; Tadano, Kiichi; Kobayashi, Daisuke; Tomita, Tetsuya; Sakae, Takeji

2016-01-01

Conversion from CT value to density is essential to a radiation treatment planning system. Generally CT value is converted to the electron density in photon therapy. In the energy range of therapeutic photon, interactions between photons and materials are dominated with Compton scattering which the cross-section depends on the electron density. The dose distribution is obtained by calculating TERMA and kernel using electron density where TERMA is the energy transferred from primary photons and kernel is a volume considering spread electrons. Recently, a new method was introduced which uses the physical density. This method is expected to be faster and more accurate than that using the electron density. As for particle therapy, dose can be calculated with CT-to-stopping power conversion since the stopping power depends on the electron density. CT-to-stopping power conversion table is also called as CT-to-water-equivalent range and is an essential concept for the particle therapy.

Computer aided detection system for Osteoporosis using low dose thoracic 3D CT images

NASA Astrophysics Data System (ADS)

Tsuji, Daisuke; Matsuhiro, Mikio; Suzuki, Hidenobu; Kawata, Yoshiki; Niki, Noboru; Nakano, Yasutaka; Harada, Masafumi; Kusumoto, Masahiko; Tsuchida, Takaaki; Eguchi, Kenji; Kaneko, Masahiro

2018-02-01

The patient of osteoporosis is about 13 million people in Japan and it is one of healthy life problems in the aging society. It is necessary to do early stage detection and treatment in order to prevent the osteoporosis. Multi-slice CT technology has been improving the three dimensional (3D) image analysis with higher resolution and shorter scan time. The 3D image analysis of thoracic vertebra can be used for supporting to diagnosis of osteoporosis. This analysis can be used for lung cancer detection at the same time. We develop method of shape analysis and CT values of spongy bone for the detection osteoporosis. Osteoporosis and lung cancer screening show high extraction rate by the thoracic vertebral evaluation CT images. In addition, we created standard pattern of CT value per thoracic vertebra for male age group using 298 low dose data.

Thoracic-abdominal imaging with a novel dual-layer spectral detector CT: intra-individual comparison of image quality and radiation dose with 128-row single-energy acquisition.

PubMed

Haneder, Stefan; Siedek, Florian; Doerner, Jonas; Pahn, Gregor; Grosse Hokamp, Nils; Maintz, David; Wybranski, Christian

2018-01-01

Background A novel, multi-energy, dual-layer spectral detector computed tomography (SDCT) is commercially available now with the vendor's claim that it yields the same or better quality of polychromatic, conventional CT images like modern single-energy CT scanners without any radiation dose penalty. Purpose To intra-individually compare the quality of conventional polychromatic CT images acquired with a dual-layer spectral detector (SDCT) and the latest generation 128-row single-energy-detector (CT128) from the same manufacturer. Material and Methods Fifty patients underwent portal-venous phase, thoracic-abdominal CT scans with the SDCT and prior CT128 imaging. The SDCT scanning protocol was adapted to yield a similar estimated dose length product (DLP) as the CT128. Patient dose optimization by automatic tube current modulation and CT image reconstruction with a state-of-the-art iterative algorithm were identical on both scanners. CT image contrast-to-noise ratio (CNR) was compared between the SDCT and CT128 in different anatomic structures. Image quality and noise were assessed independently by two readers with 5-point-Likert-scales. Volume CT dose index (CTDI vol ), and DLP were recorded and normalized to 68 cm acquisition length (DLP 68 ). Results The SDCT yielded higher mean CNR values of 30.0% ± 2.0% (26.4-32.5%) in all anatomic structures ( P < 0.001) and excellent scores for qualitative parameters surpassing the CT128 (all P < 0.0001) with substantial inter-rater agreement (κ ≥ 0.801). Despite adapted scan protocols the SDCT yielded lower values for CTDI vol (-10.1 ± 12.8%), DLP (-13.1 ± 13.9%), and DLP 68 (-15.3 ± 16.9%) than the CT128 (all P < 0.0001). Conclusion The SDCT scanner yielded better CT image quality compared to the CT128 and lower radiation dose parameters.

In vivo anthelmintic activity of Dorycnium rectum and grape seed extract against Ostertagia (Teladorsagia) circumcincta and Trichostrongylus colubriformis in sheep.

PubMed

Waghorn, T S; Molan, A L; Deighton, M; Alexander, R A; Leathwick, D M; McNabb, W C; Meagher, L P

2006-02-01

To assess the in vivo anthelmintic activity of condensed tannins (CT) in the forage species Dorycnium rectum and Medicago sativa, and in an extract from grape (Vitus vinifera) seeds (GSE), against two species of parasite, Teladorsagia (Ostertagia) circumcincta and Trichostrongylus colubriformis, at different stages of their life cycle, in sheep that were parasite-naïve or previously exposed to nematodes. In Trial 1, a factorial treatment structure was used to compare faecal nematode egg counts (FEC) and worm burdens in 40 weaned Romney lambs fed either the CT-containing forage D. rectum (12% dry matter; DM) or M. sativa (lucerne; 0.2% DM). Twenty naïve and 20 previously-exposed lambs were drenched free of parasites then reinfected with known species and numbers of parasites, and housed in pens indoors on a diet of lucerne pellets and chaffed hay. Groups of lambs (n=5 lambs per group) were fed one of the forages over one of two time periods within the parasite's life cycle. Six to nine days after the last feeding of fresh forages, faecal samples were collected for FEC, and all lambs were slaughtered and worm counts conducted. In Trial 2, 12 Suffolk x Romney lambs were surgically implanted with an abomasal cannula and then housed indoors in metabolism crates. After infection with parasites, six lambs were infused continuously over a 14-day period with a commercially available CT GSE (96% DM, made up to 34 g/L in water); the remaining lambs were infused with water. During infusion, samples were collected for egg hatch and larval development assays. After infusion, samples were collected for FEC, and all lambs were slaughtered and worm counts conducted. In Trial 1, there was a significant (p<0.001) difference in burdens of O. circumcincta between naïve lambs and those previously exposed to parasites, but no other differences were recorded. In Trial 2, lambs infused with GSE had significantly (p<0.05) fewer T. colubriformis at slaughter and significantly (p<0.001) fewer eggs hatched in the egg hatch assay (EHA) than for lambs infused with water. Overall, the differences attributable to GSE were small in magnitude, being an 11% drop in egg hatch, and an 18% drop in numbers of adult T. colubriformis after 14 days of continuous infusion. No other differences were recorded. The results indicate that the in vivo anthelmintic activity of these CT sources is, at best, modest and is unlikely to be of any practical value. Further, these data emphasise that in vitro activity is an unreliable indicator of in vivo efficacy for CT-containing forages and extracts.

Non-rigid registration of serial dedicated breast CT, longitudinal dedicated breast CT and PET/CT images using the diffeomorphic demons method.

PubMed

Santos, Jonathan; Chaudhari, Abhijit J; Joshi, Anand A; Ferrero, Andrea; Yang, Kai; Boone, John M; Badawi, Ramsey D

2014-09-01

Dedicated breast CT and PET/CT scanners provide detailed 3D anatomical and functional imaging data sets and are currently being investigated for applications in breast cancer management such as diagnosis, monitoring response to therapy and radiation therapy planning. Our objective was to evaluate the performance of the diffeomorphic demons (DD) non-rigid image registration method to spatially align 3D serial (pre- and post-contrast) dedicated breast computed tomography (CT), and longitudinally-acquired dedicated 3D breast CT and positron emission tomography (PET)/CT images. The algorithmic parameters of the DD method were optimized for the alignment of dedicated breast CT images using training data and fixed. The performance of the method for image alignment was quantitatively evaluated using three separate data sets; (1) serial breast CT pre- and post-contrast images of 20 women, (2) breast CT images of 20 women acquired before and after repositioning the subject on the scanner, and (3) dedicated breast PET/CT images of 7 women undergoing neo-adjuvant chemotherapy acquired pre-treatment and after 1 cycle of therapy. The DD registration method outperformed no registration (p < 0.001) and conventional affine registration (p ≤ 0.002) for serial and longitudinal breast CT and PET/CT image alignment. In spite of the large size of the imaging data, the computational cost of the DD method was found to be reasonable (3-5 min). Co-registration of dedicated breast CT and PET/CT images can be performed rapidly and reliably using the DD method. This is the first study evaluating the DD registration method for the alignment of dedicated breast CT and PET/CT images. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Validation of a Low Dose Simulation Technique for Computed Tomography Images

PubMed Central

Muenzel, Daniela; Koehler, Thomas; Brown, Kevin; Žabić, Stanislav; Fingerle, Alexander A.; Waldt, Simone; Bendik, Edgar; Zahel, Tina; Schneider, Armin; Dobritz, Martin; Rummeny, Ernst J.; Noël, Peter B.

2014-01-01

Purpose Evaluation of a new software tool for generation of simulated low-dose computed tomography (CT) images from an original higher dose scan. Materials and Methods Original CT scan data (100 mAs, 80 mAs, 60 mAs, 40 mAs, 20 mAs, 10 mAs; 100 kV) of a swine were acquired (approved by the regional governmental commission for animal protection). Simulations of CT acquisition with a lower dose (simulated 10–80 mAs) were calculated using a low-dose simulation algorithm. The simulations were compared to the originals of the same dose level with regard to density values and image noise. Four radiologists assessed the realistic visual appearance of the simulated images. Results Image characteristics of simulated low dose scans were similar to the originals. Mean overall discrepancy of image noise and CT values was −1.2% (range −9% to 3.2%) and −0.2% (range −8.2% to 3.2%), respectively, p>0.05. Confidence intervals of discrepancies ranged between 0.9–10.2 HU (noise) and 1.9–13.4 HU (CT values), without significant differences (p>0.05). Subjective observer evaluation of image appearance showed no visually detectable difference. Conclusion Simulated low dose images showed excellent agreement with the originals concerning image noise, CT density values, and subjective assessment of the visual appearance of the simulated images. An authentic low-dose simulation opens up opportunity with regard to staff education, protocol optimization and introduction of new techniques. PMID:25247422

What is the role of florine-18 fluorodeoxyglucose/positron emission tomography/computed tomography imaging in well-differentiated thyroid cancers with negative iodine-131 scan high thyroglobulin and normal anti-thyroglobulin levels.

PubMed

Döner, Rana Kaya; Sager, Sait; Görtan, Fatma Arzu; Topuz, Özge Vural; Akyel, Reşit; Vatankulu, Betül; Baran, Ahmet; Teksoz, Serkan; Sönmezoglu, Kerim

2016-01-01

This retrospective study aims to assess the cut-off value of thyroglobulin (Tg) levels in nux or metastatic well-differentiated thyroid cancers (DTCs) with normal anti-Tg levels using with fluorodeoxyglucose/positron emission tomography/computed tomography (FDG PET/CT). We reviewed FDG PET/CT images of 104 patients with well DTC (28 men, 76 women) whose: Iodine-131 (131 I) whole-body scanning was negative but had elevated Tg with normal anti-Tg levels. The overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of florine-18-FDG PET/CT findings were found to be 95.92%, 87.27%, 87.04%, 96.00%, and 91.35%, respectively. The best Tg cut-off value was found to be 10.4 ng/ml. In the Tg level <10.4 ng/ml group, the sensitivity, specificity, PPV, NPV, and accuracy of FDG PET/CT were found to be 94.1%, 91.30%, 88.8%, 95.4%, and 92.5%, respectively. In the other group, which Tg level ≥10.4 ng/ml, sensitivity, specificity, PPV, NPV, and accuracy of FDG PET/CT exams were found to be 96.8%, 84.3%, 86.1%, 96.4%, and 90.6%, respectively. FDG PET/CT imaging is a valuable imaging method in the evaluation of patients with elevated serum Tg levels and normal anti-Tg levels. Furthermore, it has potential utility in the dedifferentiation of active foci that are present, and in assessing optimal decision making during follow-up.

128 slice computed tomography dose profile measurement using thermoluminescent dosimeter

NASA Astrophysics Data System (ADS)

Salehhon, N.; Hashim, S.; Karim, M. K. A.; Ang, W. C.; Musa, Y.; Bahruddin, N. A.

2017-05-01

The increasing use of computed tomography (CT) in clinical practice marks the needs to understand the dose descriptor and dose profile. The purposes of the current study were to determine the CT dose index free-in-air (CTDIair) in 128 slice CT scanner and to evaluate the single scan dose profile (SSDP). Thermoluminescent dosimeters (TLD-100) were used to measure the dose profile of the scanner. There were three sets of CT protocols where the tube potential (kV) setting was manipulated for each protocol while the rest of parameters were kept constant. These protocols were based from routine CT abdominal examinations for male adult abdomen. It was found that the increase of kV settings made the values of CTDIair increased as well. When the kV setting was changed from 80 kV to 120 kV and from 120 kV to 140 kV, the CTDIair values were increased as much as 147.9% and 53.9% respectively. The highest kV setting (140 kV) led to the highest CTDIair value (13.585 mGy). The p-value of less than 0.05 indicated that the results were statistically different. The SSDP showed that when the kV settings were varied, the peak sharpness and height of Gaussian function profiles were affected. The full width at half maximum (FWHM) of dose profiles for all protocols were coincided with the nominal beam width set for the measurements. The findings of the study revealed much information on the characterization and performance of 128 slice CT scanner.

Identification of infusion strategy for achieving repeatable nanoparticle distribution and quantification of thermal dosage using micro-CT Hounsfield unit in magnetic nanoparticle hyperthermia.

PubMed

LeBrun, Alexander; Joglekar, Tejashree; Bieberich, Charles; Ma, Ronghui; Zhu, Liang

2016-01-01

The objective of this study was to identify an injection strategy leading to repeatable nanoparticle deposition patterns in tumours and to quantify volumetric heat generation rate distribution based on micro-CT Hounsfield unit (HU) in magnetic nanoparticle hyperthermia. In vivo animal experiments were performed on graft prostatic cancer (PC3) tumours in immunodeficient mice to investigate whether lowering ferrofluid infusion rate improves control of the distribution of magnetic nanoparticles in tumour tissue. Nanoparticle distribution volume obtained from micro-CT scan was used to evaluate spreading of the nanoparticles from the injection site in tumours. Heating experiments were performed to quantify relationships among micro-CT HU values, local nanoparticle concentrations in the tumours, and the ferrofluid-induced volumetric heat generation rate (q(MNH)) when nanoparticles were subject to an alternating magnetic field. An infusion rate of 3 µL/min was identified to result in the most repeatable nanoparticle distribution in PC3 tumours. Linear relationships have been obtained to first convert micro-CT greyscale values to HU values, then to local nanoparticle concentrations, and finally to nanoparticle-induced q(MNH) values. The total energy deposition rate in tumours was calculated and the observed similarity in total energy deposition rates in all three infusion rate groups suggests improvement in minimising nanoparticle leakage from the tumours. The results of this study demonstrate that micro-CT generated q(MNH) distribution and tumour physical models improve predicting capability of heat transfer simulation for designing reliable treatment protocols using magnetic nanoparticle hyperthermia.

Derivation of new diagnostic reference levels for neuro-paediatric computed tomography examinations in Switzerland.

PubMed

Wagner, Franca; Bize, Julie; Racine, Damien; Le Coultre, Regis; Francis, Verdun; Trueb, Philipp; Treier, Reto

2018-05-22

Definition of new national diagnostic reference levels (DRLs) for volume computed tomography dose index (CTDIvol) and dose length product (DLP) for neuro-paediatric CT examinations depending on the medical indication. Methods: Paediatric cranial CT data sets acquired between January 2013 and December 2016 were retrospectively collected between July 2016 and March 2017 from the eight largest university and cantonal hospitals that perform most of the neuro-paediatric CTs in Switzerland. A consensus review of CTDIvol and DLP was undertaken for the three defined anatomical regions: brain, facial bone and petrous bone; each with and without contrast medium application. All indications for cranial CT imaging in paediatrics were assigned to one of these three regions. Descriptive statistical analysis of the distribution of the median values for CTDIvol and DLP yielded minimum, maximum, 25th percentile (1st quartile), median (2nd quartile) and 75th percentile (3rd quartile). New DRLs for neuro-paediatric CT examinations in Switzerland were based on the 75th percentiles of the distributions of the median values of all eight centres. Where appropriate, values were rounded such that the DRLs increase or at least remain constant as the age of the patient increases. Results: Our results revealed DRLs for CTDIvol and DLP up to 20% lower than the DRLs used so far in Switzerland and elsewhere in Europe. Conclusions: This study provides Swiss neuro-paediatric CT DRL values to establish optimum conditions for paediatric cranial CT examinations. Periodic national updates of DRLs, following international comparisons, are essential. . Creative Commons Attribution license.

Prognostic value of tumor necrosis at CT in diffuse large B-cell lymphoma.

PubMed

Adams, Hugo J A; de Klerk, John M H; Fijnheer, Rob; Dubois, Stefan V; Nievelstein, Rutger A J; Kwee, Thomas C

2015-03-01

To determine the prognostic value of tumor necrosis at computed tomography (CT) in newly diagnosed diffuse large B-cell lymphoma (DLBCL). This retrospective study included 51 patients with newly diagnosed DLBCL who had undergone both unenhanced and intravenous contrast-enhanced CT before R-CHOP (rituximab, cyclophosphamide, hydroxydaunorubicin, oncovin and prednisolone) chemo-immunotherapy. Presence of tumor necrosis was visually and quantitatively assessed at CT. Associations between tumor necrosis status at CT and the National Comprehensive Cancer Network (NCCN) International Prognostic Index (IPI) factors were assessed. Cox regression analysis was used to determine the prognostic impact of NCCN-IPI scores and tumor necrosis status at CT. There were no correlations between tumor necrosis status at CT and the NCCN-IPI factors categorized age (ρ=-0.042, P=0.765), categorized lactate dehydrogenase (LDH) ratio (ρ=0.201, P=0.156), extranodal disease in major organs (φ=-0.245, P=0.083), Ann Arbor stage III/IV disease (φ=-0.208, P=0.141), and Eastern Cooperative Oncology Group (ECOG) performance status (φ=0.015, P=0.914). In the multivariate Cox proportional hazards model, only tumor necrosis status at CT was an independent predictive factor of progression-free survival (P=0.003) and overall survival (P=0.004). The findings of this study indicate the prognostic potential of tumor necrosis at CT in newly diagnosed DLBCL. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Consequences of additional use of PET information for target volume delineation and radiotherapy dose distribution for esophageal cancer.

PubMed

Muijs, Christina T; Schreurs, Liesbeth M; Busz, Dianne M; Beukema, Jannet C; van der Borden, Arnout J; Pruim, Jan; Van der Jagt, Eric J; Plukker, John Th; Langendijk, Johannes A

2009-12-01

To determine the consequences of target volume (TV) modifications, based on the additional use of PET information, on radiation planning, assuming PET/CT-imaging represents the true extent of the tumour. For 21 patients with esophageal cancer, two separate TV's were retrospectively defined based on CT (CT-TV) and co-registered PET/CT images (PET/CT-TV). Two 3D-CRT plans (prescribed dose 50.4 Gy) were constructed to cover the corresponding TV's. Subsequently, these plans were compared for target coverage, normal tissue dose-volume histograms and the corresponding normal tissue complication probability (NTCP) values. The addition of PET led to the modification of CT-TV with at least 10% in 12 of 21 patients (57%) (reduction in 9, enlargement in 3). PET/CT-TV was inadequately covered by the CT-based treatment plan in 8 patients (36%). Treatment plan modifications resulted in significant changes (p<0.05) in dose distributions to heart and lungs. Corresponding changes in NTCP values ranged from -3% to +2% for radiation pneumonitis and from -0.2% to +1.2% for cardiac mortality. This study demonstrated that TV's based on CT might exclude PET-avid disease. Consequences are under dosing and thereby possibly ineffective treatment. Moreover, the addition of PET in radiation planning might result in clinical important changes in NTCP.

Demons deformable registration of CT and cone-beam CT using an iterative intensity matching approach.

PubMed

Nithiananthan, Sajendra; Schafer, Sebastian; Uneri, Ali; Mirota, Daniel J; Stayman, J Webster; Zbijewski, Wojciech; Brock, Kristy K; Daly, Michael J; Chan, Harley; Irish, Jonathan C; Siewerdsen, Jeffrey H

2011-04-01

A method of intensity-based deformable registration of CT and cone-beam CT (CBCT) images is described, in which intensity correction occurs simultaneously within the iterative registration process. The method preserves the speed and simplicity of the popular Demons algorithm while providing robustness and accuracy in the presence of large mismatch between CT and CBCT voxel values ("intensity"). A variant of the Demons algorithm was developed in which an estimate of the relationship between CT and CBCT intensity values for specific materials in the image is computed at each iteration based on the set of currently overlapping voxels. This tissue-specific intensity correction is then used to estimate the registration output for that iteration and the process is repeated. The robustness of the method was tested in CBCT images of a cadaveric head exhibiting a broad range of simulated intensity variations associated with x-ray scatter, object truncation, and/or errors in the reconstruction algorithm. The accuracy of CT-CBCT registration was also measured in six real cases, exhibiting deformations ranging from simple to complex during surgery or radiotherapy guided by a CBCT-capable C-arm or linear accelerator, respectively. The iterative intensity matching approach was robust against all levels of intensity variation examined, including spatially varying errors in voxel value of a factor of 2 or more, as can be encountered in cases of high x-ray scatter. Registration accuracy without intensity matching degraded severely with increasing magnitude of intensity error and introduced image distortion. A single histogram match performed prior to registration alleviated some of these effects but was also prone to image distortion and was quantifiably less robust and accurate than the iterative approach. Within the six case registration accuracy study, iterative intensity matching Demons reduced mean TRE to (2.5 +/- 2.8) mm compared to (3.5 +/- 3.0) mm with rigid registration. A method was developed to iteratively correct CT-CBCT intensity disparity during Demons registration, enabling fast, intensity-based registration in CBCT-guided procedures such as surgery and radiotherapy, in which CBCT voxel values may be inaccurate. Accurate CT-CBCT registration in turn facilitates registration of multimodality preoperative image and planning data to intraoperative CBCT by way of the preoperative CT, thereby linking the intraoperative frame of reference to a wealth of preoperative information that could improve interventional guidance.

The diagnostic value of 18F-FDG-PET/CT and MRI in suspected vertebral osteomyelitis - a prospective study.

PubMed

Kouijzer, Ilse J E; Scheper, Henk; de Rooy, Jacky W J; Bloem, Johan L; Janssen, Marcel J R; van den Hoven, Leon; Hosman, Allard J F; Visser, Leo G; Oyen, Wim J G; Bleeker-Rovers, Chantal P; de Geus-Oei, Lioe-Fee

2018-05-01

The aim of this study was to determine the diagnostic value of 18 F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT) and magnetic resonance imaging (MRI) in diagnosing vertebral osteomyelitis. From November 2015 until December 2016, 32 patients with suspected vertebral osteomyelitis were prospectively included. All patients underwent both 18 F-FDG-PET/CT and MRI within 48 h. All images were independently reevaluated by two radiologists and two nuclear medicine physicians who were blinded to each others' image interpretation. 18 F-FDG-PET/CT and MRI were compared to the clinical diagnosis according to international guidelines. For 18 F-FDG-PET/CT, sensitivity, specificity, PPV, and NPV in diagnosing vertebral osteomyelitis were 100%, 83.3%, 90.9%, and 100%, respectively. For MRI, sensitivity, specificity, PPV, and NPV were 100%, 91.7%, 95.2%, and 100%, respectively. MRI detected more epidural/spinal abscesses. An important advantage of 18 F-FDG-PET/CT is the detection of metastatic infection (16 patients, 50.0%). 18 F-FDG-PET/CT and MRI are both necessary techniques in diagnosing vertebral osteomyelitis. An important advantage of 18 F-FDG-PET/CT is the visualization of metastatic infection, especially in patients with bacteremia. MRI is more sensitive in detection of small epidural abscesses.

Diagnostic value of 64-slice spiral computed tomography imaging of the urinary tract during the excretory phase for urinary tract obstruction.

PubMed

Zhao, De-Li; Jia, Guang-Sheng; Chen, Peng; Liu, Xin-Ding; Shu, Sheng-Jie; Ling, Zai-Sheng; Fan, Ting-Ting; Shen, Xiu-Fen; Zhang, Jin-Ling

2017-11-01

The present study aimed to assess the diagnostic value of 64-slice spiral computed tomography (CT) imaging of the urinary tract during the excretory phase for urinary tract obstruction. CT imaging of the urinary tract during the excretory phase was performed in 46 patients that had been diagnosed with urinary tract obstruction by B-mode ultrasound imaging or clinical manifestations. It was demonstrated that out of the 46 patients, 18 had pelvic and ureteral calculi, 12 cases had congenital malformations, 3 had ureteral stricture caused by urinary tract infection and 13 cases had malignant tumors of the urinary tract. The average X-ray dose planned for the standard CT scan of the urinary tract group 1 was 14.11±5.45 mSv, while the actual X-ray dose administered for the CT scan during the excretory phase group 2 was 9.01±4.56 mSv. The difference between the two groups was statistically significant (t=15.36; P<0.01). The results of the present study indicate that CT scanning of the urinary tract during the excretory phase has a high diagnostic value for urinary tract obstruction.

Three-dimensional computed tomographic volumetry precisely predicts the postoperative pulmonary function.

PubMed

Kobayashi, Keisuke; Saeki, Yusuke; Kitazawa, Shinsuke; Kobayashi, Naohiro; Kikuchi, Shinji; Goto, Yukinobu; Sakai, Mitsuaki; Sato, Yukio

2017-11-01

It is important to accurately predict the patient's postoperative pulmonary function. The aim of this study was to compare the accuracy of predictions of the postoperative residual pulmonary function obtained with three-dimensional computed tomographic (3D-CT) volumetry with that of predictions obtained with the conventional segment-counting method. Fifty-three patients scheduled to undergo lung cancer resection, pulmonary function tests, and computed tomography were enrolled in this study. The postoperative residual pulmonary function was predicted based on the segment-counting and 3D-CT volumetry methods. The predicted postoperative values were compared with the results of postoperative pulmonary function tests. Regarding the linear correlation coefficients between the predicted postoperative values and the measured values, those obtained using the 3D-CT volumetry method tended to be higher than those acquired using the segment-counting method. In addition, the variations between the predicted and measured values were smaller with the 3D-CT volumetry method than with the segment-counting method. These results were more obvious in COPD patients than in non-COPD patients. Our findings suggested that the 3D-CT volumetry was able to predict the residual pulmonary function more accurately than the segment-counting method, especially in patients with COPD. This method might lead to the selection of appropriate candidates for surgery among patients with a marginal pulmonary function.

The significance of 99mTc-MAA SPECT/CT liver perfusion imaging in treatment planning for 90Y-microsphere selective internal radiation treatment.

PubMed

Ahmadzadehfar, Hojjat; Sabet, Amir; Biermann, Kim; Muckle, Marianne; Brockmann, Holger; Kuhl, Christiane; Wilhelm, Kai; Biersack, Hans-Jürgen; Ezziddin, Samer

2010-08-01

Selective internal radiation therapy (SIRT), a catheter-based liver-directed modality for treating primary and metastatic liver cancer, requires appropriate planning to maximize its therapeutic response and minimize its side effects. (99m)Tc-macroaggregated albumin (MAA) scanning should precede the therapy to detect any extrahepatic shunting to the lung or gastrointestinal tract. Our aim was to compare the ability of SPECT/CT with that of planar imaging and SPECT in the detection and localization of extrahepatic (99m)Tc-MAA accumulation and to evaluate the impact of SPECT/CT on SIRT treatment planning and its added value to angiography in this setting. Ninety diagnostic hepatic angiograms with (99m)Tc-MAA were obtained for 76 patients with different types of cancer. All images were reviewed retrospectively for extrahepatic MAA deposition in the following order: planar, non-attenuation-corrected SPECT, and SPECT/CT. Review of angiograms and follow-up of patients with abdominal shunting served as reference standards. Extrahepatic accumulation was detected by planar imaging, SPECT, and SPECT/CT in 12%, 17%, and 42% of examinations, respectively. The sensitivity for detecting extrahepatic shunting with planar imaging, SPECT, and SPECT/CT was 32%, 41%, and 100%, respectively; specificity was 98%, 98%, and 93%, respectively. The respective positive predictive values were 92%, 93%, and 89%, and the respective negative predictive values were 71%, 73%, and 100%. The therapy plan was changed according to the results of planar imaging, SPECT, and SPECT/CT in 7.8%, 8.9%, and 29% of patients, respectively. In pre-SIRT planning, (99m)Tc-MAA SPECT/CT is valuable for identifying extrahepatic visceral sites at risk for postradioembolization complications.

Rectosigmoid endometriosis: comparison between CT water enema and video laparoscopy.

PubMed

Stabile Ianora, A A; Moschetta, M; Lorusso, F; Lattarulo, S; Telegrafo, M; Rella, L; Scardapane, A

2013-09-01

To evaluate the accuracy of water enema computed tomography (CT) for predicting the location of endometriosis in patients with contraindications to magnetic resonance imaging (MRI), focusing on rectosigmoid lesions and having laparoscopic and histological data as the reference standard. Thirty-three women (mean age 33.4 ± 3.1 years) suspected of having deep pelvic endometriosis underwent 64-row CT and video laparoscopy within 4 weeks. Two radiologists blinded to the clinical data evaluated the CT images obtained after colonic retrograde distension using water as the contrast medium, and a comparison with laparoscopic and histological findings was performed. CT sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated. The radiation dose to patients was estimated. Cohen's weighted kappa (κ) test was used to evaluate the interobserver agreement. In 23 out of 33 patients (69%) intestinal implants were found at surgery and pathological examinations. CT confirmed the diagnosis of rectosigmoid endometriosis in 20 out of 23 implants. Three nodules located on the proximal sigmoid colon (two serosal lesions and one infiltrating the muscularis layer) with a diameter of less than 1 cm were not diagnosed. CT sensitivity, specificity, PPV, NPV, and accuracy values were 87, 100, 100, 77, and 91%, respectively. The mean effective dose estimate was 6.30 ± 1.7 mSv. Almost perfect agreement between the two readers was found (k = 0.84). Water enema CT can play a role in the diagnosis of bowel endometriosis and represents another accurate potential tool for video laparoscopic approaches, especially in patients for whom MRI is contraindicated. Copyright © 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Transatlantic Comparison of CT Radiation Doses in the Era of Radiation Dose-Tracking Software.

PubMed

Parakh, Anushri; Euler, Andre; Szucs-Farkas, Zsolt; Schindera, Sebastian T

2017-12-01

The purpose of this study is to compare diagnostic reference levels from a local European CT dose registry, using radiation-tracking software from a large patient sample, with preexisting European and North American diagnostic reference levels. Data (n = 43,761 CT scans obtained over the course of 2 years) for the European local CT dose registry were obtained from eight CT scanners at six institutions. Means, medians, and interquartile ranges of volumetric CT dose index (CTDI vol ), dose-length product (DLP), size-specific dose estimate, and effective dose values for CT examinations of the head, paranasal sinuses, thorax, pulmonary angiogram, abdomen-pelvis, renal-colic, thorax-abdomen-pelvis, and thoracoabdominal angiogram were obtained using radiation-tracking software. Metrics from this registry were compared with diagnostic reference levels from Canada and California (published in 2015), the American College of Radiology (ACR) dose index registry (2015), and national diagnostic reference levels from local CT dose registries in Switzerland (2010), the United Kingdom (2011), and Portugal (2015). Our local registry had a lower 75th percentile CTDI vol for all protocols than did the individual internationally sourced data. Compared with our study, the ACR dose index registry had higher 75th percentile CTDI vol values by 55% for head, 240% for thorax, 28% for abdomen-pelvis, 42% for thorax-abdomen-pelvis, 128% for pulmonary angiogram, 138% for renal-colic, and 58% for paranasal sinus studies. Our local registry had lower diagnostic reference level values than did existing European and North American diagnostic reference levels. Automated radiation-tracking software could be used to establish and update existing diagnostic reference levels because they are capable of analyzing large datasets meaningfully.

Circulating tumor DNA evaluated by Next-Generation Sequencing is predictive of tumor response and prolonged clinical benefit with nivolumab in advanced non-small cell lung cancer.

PubMed

Giroux Leprieur, Etienne; Herbretau, Guillaume; Dumenil, Coraline; Julie, Catherine; Giraud, Violaine; Labrune, Sylvie; Dumoulin, Jennifer; Tisserand, Julie; Emile, Jean-François; Blons, Hélène; Chinet, Thierry

2018-01-01

Nivolumab is an anti-PD1 antibody, given in second-line or later treatment in advanced non-small cell lung cancer (NSCLC). The objective of this study was to describe the predictive value of circulating tumor DNA (ctDNA) on the efficacy of nivolumab in advanced NSCLC. We prospectively included all consecutive patients with advanced NSCLC treated with nivolumab in our Department between June 2015 and October 2016. Plasma samples were obtained before the first injection of nivolumab and at the first tumor evaluation with nivolumab. ctDNA was analyzed by Next-Generation Sequencing (NGS), and the predominant somatic mutation was followed for each patient and correlated with tumor response, clinical benefit (administration of nivolumab for more than 6 months), and progression-free survival (PFS). Of 23 patients, 15 had evaluable NGS results at both times of analysis. ctDNA concentration at the first tumor evaluation and ctDNA change correlated with tumor response, clinical benefit and PFS. ROC curve analyses showed good diagnostic performances for tumor response and clinical benefit, both for ctDNA concentration at the first tumor evaluation (tumor response: positive predictive value (PPV) at 100.0% and negative predictive value (NPV) at 71.0%; clinical benefit: PPV at 83.3% and NPV 77.8%) and the ctDNA change (tumor response: PPV 100.0% and NPV 62.5%; clinical benefit: PPV 100.0% and NPV 80.0%). Patients without ctDNA concentration increase >9% at 2 months had a long-term benefit of nivolumab. In conclusion, NGS analysis of ctDNA allows the early detection of tumor response and long-term clinical benefit with nivolumab in NSCLC.

Radiotracer Imaging Allows for Noninvasive Detection and Quantification of Abnormalities in Angiosome Foot Perfusion in Diabetic Patients With Critical Limb Ischemia and Nonhealing Wounds

PubMed Central

Alvelo, Jessica L.; Papademetris, Xenophon; Mena-Hurtado, Carlos; Jeon, Sangchoon; Sumpio, Bauer E.; Sinusas, Albert J.

2018-01-01

Background: Single photon emission computed tomography (SPECT)/computed tomography (CT) imaging allows for assessment of skeletal muscle microvascular perfusion but has not been quantitatively assessed in angiosomes, or 3-dimensional vascular territories, of the foot. This study assessed and compared resting angiosome foot perfusion between healthy subjects and diabetic patients with critical limb ischemia (CLI). Additionally, the relationship between SPECT/CT imaging and the ankle–brachial index—a standard tool for evaluating peripheral artery disease—was assessed. Methods and Results: Healthy subjects (n=9) and diabetic patients with CLI and nonhealing ulcers (n=42) underwent SPECT/CT perfusion imaging of the feet. CT images were segmented into angiosomes for quantification of relative radiotracer uptake, expressed as standardized uptake values. Standardized uptake values were assessed in ulcerated angiosomes of patients with CLI and compared with whole-foot standardized uptake values in healthy subjects. Serial SPECT/CT imaging was performed to assess uptake kinetics of technetium-99m-tetrofosmin. The relationship between angiosome perfusion and ankle–brachial index was assessed via correlational analysis. Resting perfusion was significantly lower in CLI versus healthy subjects (P=0.0007). Intraclass correlation coefficients of 0.95 (healthy) and 0.93 (CLI) demonstrated excellent agreement between serial perfusion measurements. Correlational analysis, including healthy and CLI subjects, demonstrated a significant relationship between ankle–brachial index and SPECT/CT (P=0.01); however, this relationship was not significant for diabetic CLI patients only (P=0.2). Conclusions: SPECT/CT imaging assesses regional foot perfusion and detects abnormalities in microvascular perfusion that may be undetectable by conventional ankle–brachial index in patients with diabetes mellitus. SPECT/CT may provide a novel approach for evaluating responses to targeted therapies. PMID:29748311

Sagittal-lung CT measurements in the evaluation of asthma-COPD overlap syndrome: a distinctive phenotype from COPD alone.

PubMed

Qu, Yanjuan; Cao, Yiyuan; Liao, Meiyan; Lu, Zhiyan

2017-07-01

This study aimed at investigating the capability of sagittal-lung computed tomography (CT) measurements in differentiating chronic obstructive pulmonary disease (COPD) and asthma-COPD overlap syndrome (ACOS). Clinical and high-resolution CT of 229 patients including 123 pure COPD patients and 106 ACOS patients were included. Sagittal-lung CT measurements in terms of bilateral lung height (LH), anterior-posterior lung diameter (APLD), diaphragm height (DH), and anterior sterno-diaphragmatic angle (ASDA), as well as inter-pulmonary septum length (IPSL) on axial images were measured both before and after bronchodilator (BD) administration. Comparisons of clinical characteristics and CT measurements between patient groups were performed. All pre-BD quantitative sagittal features measuring diaphragm flattening and hyperinflation were not significantly different between patients with COPD and patients with ACOS (P values all >0.05). Following BD administration, the ACOS patients exhibited lower left LH, bilateral APLD, and bilateral ASDA, but higher right DH, compared to pure COPD patients (P values all <0.05). Right LH, left DH and IPSL were not significantly different between patient groups. Besides, variations of all sagittal-lung CT measurements were significantly larger in patients with ACOS than in patients with pure COPD (P values all <0.001) and showed high performance in differentiating these two kinds of patient, with diagnostic sensitivities ranging from 76.4 to 97.2%, specificities ranging from 86.2 to 100.0%, and accuracies ranging from 80.9 to 90.7%. Sagittal-lung CT measurements allow for differentiating patients with ACOS from those with pure COPD. The ACOS patients had larger post-BD variations of sagittal-lung CT measurements than patients with pure COPD.

Flexible lithium–oxygen battery based on a recoverable cathode

PubMed Central

Liu, Qing-Chao; Xu, Ji-Jing; Xu, Dan; Zhang, Xin-Bo

2015-01-01

Although flexible power sources are crucial for the realization next-generation flexible electronics, their application in such devices is hindered by their low theoretical energy density. Rechargeable lithium–oxygen (Li–O2) batteries can provide extremely high specific energies, while the conventional Li–O2 battery is bulky, inflexible and limited by the absence of effective components and an adjustable cell configuration. Here we show that a flexible Li–O2 battery can be fabricated using unique TiO2 nanowire arrays grown onto carbon textiles (NAs/CT) as a free-standing cathode and that superior electrochemical performances can be obtained even under stringent bending and twisting conditions. Furthermore, the TiO2 NAs/CT cathode features excellent recoverability, which significantly extends the cycle life of the Li–O2 battery and lowers its life cycle cost. PMID:26235205

Hypercalcitoninemia in infancy.

PubMed

Cannarozzi, D B; Canale, D D; Donabedian, R K

1976-02-02

Immunoreactive calcitonin (iCT) was measured in 19 infants with neonatal hypocalcemia. The infants had a variety of neonatal diseases and stresses. iCT levels were generally elevated to two to 20 times the adult values. Poor correlation existed between the infant age and the level of iCT or between iCT alone and the serum calcium. However, there was significant correlation between the serum calcium and the ratio of the iCT to infant age from conception, suggesting that both infant age and iCT levels in combination may be related to hypocalcemia. Also, it appears that a variety of neonatal stresses may be associated with increased sensitivity to the hypocalcemic effect of iCT, as well as increased levels of iCT.

Results of the two incidence screenings in the National Lung Screening Trial.

PubMed

Aberle, Denise R; DeMello, Sarah; Berg, Christine D; Black, William C; Brewer, Brenda; Church, Timothy R; Clingan, Kathy L; Duan, Fenghai; Fagerstrom, Richard M; Gareen, Ilana F; Gatsonis, Constantine A; Gierada, David S; Jain, Amanda; Jones, Gordon C; Mahon, Irene; Marcus, Pamela M; Rathmell, Joshua M; Sicks, JoRean

2013-09-05

The National Lung Screening Trial was conducted to determine whether three annual screenings (rounds T0, T1, and T2) with low-dose helical computed tomography (CT), as compared with chest radiography, could reduce mortality from lung cancer. We present detailed findings from the first two incidence screenings (rounds T1 and T2). We evaluated the rate of adherence of the participants to the screening protocol, the results of screening and downstream diagnostic tests, features of the lung-cancer cases, and first-line treatments, and we estimated the performance characteristics of both screening methods. At the T1 and T2 rounds, positive screening results were observed in 27.9% and 16.8% of participants in the low-dose CT group and in 6.2% and 5.0% of participants in the radiography group, respectively. In the low-dose CT group, the sensitivity was 94.4%, the specificity was 72.6%, the positive predictive value was 2.4%, and the negative predictive value was 99.9% at T1; at T2, the positive predictive value increased to 5.2%. In the radiography group, the sensitivity was 59.6%, the specificity was 94.1%, the positive predictive value was 4.4%, and the negative predictive value was 99.8% at T1; both the sensitivity and the positive predictive value increased at T2. Among lung cancers of known stage, 87 (47.5%) were stage IA and 57 (31.1%) were stage III or IV in the low-dose CT group at T1; in the radiography group, 31 (23.5%) were stage IA and 78 (59.1%) were stage III or IV at T1. These differences in stage distribution between groups persisted at T2. Low-dose CT was more sensitive in detecting early-stage lung cancers, but its measured positive predictive value was lower than that of radiography. As compared with radiography, the two annual incidence screenings with low-dose CT resulted in a decrease in the number of advanced-stage cancers diagnosed and an increase in the number of early-stage lung cancers diagnosed. (Funded by the National Cancer Institute; NLST ClinicalTrials.gov number, NCT00047385.).

SU-C-207A-03: Development of Proton CT Imaging System Using Thick Scintillator and CCD Camera

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanaka, S; Uesaka, M; Nishio, T

2016-06-15

Purpose: In the treatment planning of proton therapy, Water Equivalent Length (WEL), which is the parameter for the calculation of dose and the range of proton, is derived by X-ray CT (xCT) image and xCT-WEL conversion. However, about a few percent error in the accuracy of proton range calculation through this conversion has been reported. The purpose of this study is to construct a proton CT (pCT) imaging system for an evaluation of the error. Methods: The pCT imaging system was constructed with a thick scintillator and a cooled CCD camera, which acquires the two-dimensional image of integrated value ofmore » the scintillation light toward the beam direction. The pCT image is reconstructed by FBP method using a correction between the light intensity and residual range of proton beam. An experiment for the demonstration of this system was performed with 70-MeV proton beam provided by NIRS cyclotron. The pCT image of several objects reconstructed from the experimental data was evaluated quantitatively. Results: Three-dimensional pCT images of several objects were reconstructed experimentally. A finestructure of approximately 1 mm was clearly observed. The position resolution of pCT image was almost the same as that of xCT image. And the error of proton CT pixel value was up to 4%. The deterioration of image quality was caused mainly by the effect of multiple Coulomb scattering. Conclusion: We designed and constructed the pCT imaging system using a thick scintillator and a CCD camera. And the system was evaluated with the experiment by use of 70-MeV proton beam. Three-dimensional pCT images of several objects were acquired by the system. This work was supported by JST SENTAN Grant Number 13A1101 and JSPS KAKENHI Grant Number 15H04912.« less

Added value of SPECT/spiral CT versus SPECT or CT alone in diagnosing solitary skeletal lesions.

PubMed

Zhang, Yiqiu; Li, Beilei; Shi, Hongcheng; Yu, Haojun; Gu, Yushen; Xiu, Yan

2017-08-14

The aim of this study was to investigate the added value of SPECT/spiral CT versus SPECT or CT alone in the differential diagnosis of solitary skeletal lesions. This was a retrospective study on a total of 69 patients who had a solitary skeletal "hot spot" that could not be definitively diagnosed using planar scintigraphy. Thus, SPECT/spiral CT was performed on the indeterminate lesions. SPECT, CT and SPECT/spiral CT images were independently interpreted by two experienced doctors who have both identification of CT and nuclear medicine. Each lesion was graded on a 4-point diagnostic scale (1: benign, 2: likely benign, 3: likely malignant, 4: malignant). The final diagnosis of each lesion was based on pathological confirmation after surgery within 3 weeks of the bone scan. Final diagnoses based on the pathological results revealed that 43 of the 69 patients were diagnosed with malignancy, and the remaining 26 patients were diagnosed as having benign lesions. For SPECT and CT scans, both of the reviewers rated 55.1 % (38/69) and 37.7 % (26/69) of lesions as equivocal, with the help of SPECT/CT, 33.3 % (23/69) of lesions were rated as equivocal. The diagnostic accuracies of SPECT, CT alone and SPECT/CT were 66.7 % (46/69) ,82.6 % (57/69) and 85.5 %(59/69), respectively. The kappa scores for the degree of agreement between SPECT, CT alone or SPECT/CT with pathological results were 0.185 (p = 0.054) , 0.612 (p < 0.001) and 0.671 (p < 0.001), respectively. Compared with SPECT or imaging alone, SPECT/spiral CT imaging was more accurate and valuable in the differential diagnosis of solitary skeletal lesions and resulted in significantly fewer equivocal findings.

CT coronary angiography and exercise ECG in a population with chest pain and low-to-intermediate pre-test likelihood of coronary artery disease.

PubMed

Maffei, Erica; Seitun, Sara; Martini, Chiara; Palumbo, Alessandro; Tarantini, Giuseppe; Berti, Elena; Grilli, Roberto; Tedeschi, Carlo; Messalli, Giancarlo; Guaricci, Andrea; Weustink, Annick C; Mollet, Nico Ra; Cademartiri, Filippo

2010-12-01

To evaluate diagnostic accuracy of exercise ECG (ex-ECG) versus 64-slice CT coronary angiography (CT-CA) for the detection of significant coronary artery stenosis in a population with low-to-intermediate pre-test likelihood of coronary artery disease (CAD). Retrospective single centre. Tertiary academic hospital. 177 consecutive patients (88 men, 89 women, mean age 53.5±7.6 years) with chest pain and low-to-intermediate pre-test likelihood of CAD were retrospectively enrolled. All patients underwent ex-ECG, CT-CA and invasive coronary angiography (ICA). A lumen diameter reduction of ≥50% was considered as significant stenosis for CT-CA. Ex-ECG was classified as positive, negative or non-diagnostic. were compared with ICA. Diagnostic accuracy of CT-CA and ex-ECG was calculated using ICA as the reference standard. A parallel comparative analysis using a cut-off value of 70% for significant lumen reduction was also performed too. Results ICA disclosed an absence of significant stenosis (≥50% luminal narrowing) in 85.3% (151/177) patients, single-vessel disease in 9.0% (16/177) patients and multivessel disease in 5.6% (10/177) patients. Prevalence of obstructive disease at ICA was 14.7% (26/177). Sensitivity, specificity, positive and negative predictive values at the patient level were 100.0%, 98.7%, 92.9%, 100%, respectively, for CT-CA and 46.2%, 16.6%, 8.7%, 64.1%, respectively, for ex-ECG. Agreement between CT-CA and ex-ECG was 20.9%. CT-CA performed equally well in men and women, while ex-ECG had a better performance in men. After considering the cut-off value of 70% for significant stenosis, the difference between CT-CA and ex-ECG remained significant (p<0.01), with a low agreement (21.5%). CT-CA provides optimal diagnostic performance in patients with atypical chest pain and low-to-intermediate risk of CAD. Ex-ECG has poor diagnostic accuracy in this population. Concerns are related to risk of radiation dose versus the benefits of correct disease stratification.

Evaluation of 18F-FDG PET/CT Parameters for Detection of Lymph Node Metastasis in Cutaneous Melanoma.

PubMed

Cha, Jongtae; Kim, Soyoung; Wang, Jiyoung; Yun, Mijin; Cho, Arthur

2018-02-01

The purpose of this study was to investigate the value of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) parameters in the detection of regional lymph node (LN) metastasis in patients with cutaneous melanoma. We evaluated patients with cutaneous melanoma who underwent FDG PET/CT for initial staging or recurrence evaluation. A total of 103 patients were enrolled, and 165 LNs were evaluated. LNs that were confirmed pathologically or by follow-up imaging were included in this study. PET parameters, including maximum standardized uptake value (SUVmax), total lesion glycolysis and tumour-to-liver ratio, were used to determine the presence of metastases, and the results were compared with CT-determined LN metastasis. Receiver operating characteristic (ROC) curve analysis was used to determine the optimal cut-off values of the FDG PET parameters. A total of 93 LNs were malignant, and 84 LNs were smaller than 10 mm. In all 165 LNs, an SUVmax of >2.51 showed a sensitivity of 73.1%, a specificity of 88.9%, and an accuracy of 80.0% in detecting metastatic LNs. CT showed a higher specificity (87.3%) and lower accuracy (65.5%). For non-enlarged regional LNs (<10 mm), an SUVmax cut-off value of 1.4 showed the highest negative predictive value (81.3%). For enlarged LNs (≥10 mm), an SUVmax cut-off value of 2.4 showed the highest sensitivity (90.7%) and accuracy (88.9%) in detecting metastatic LNs. In patients with cutaneous melanoma, an SUVmax of >2.4 showed a high sensitivity (91%) and accuracy (89%) in detecting metastasis in LNs ≥1 cm, and LNs <1 cm with an SUVmax <1.4 were likely to be benign.

Feasibility of using 'lung density' values estimated from EIT images for clinical diagnosis of lung abnormalities in mechanically ventilated ICU patients.

PubMed

Nebuya, Satoru; Koike, Tomotaka; Imai, Hiroshi; Iwashita, Yoshiaki; Brown, Brian H; Soma, Kazui

2015-06-01

This paper reports on the results of a study which compares lung density values obtained from electrical impedance tomography (EIT), clinical diagnosis and CT values (HU) within a region of interest in the lung. The purpose was to assess the clinical use of lung density estimation using EIT data. In 11 patients supported by a mechanical ventilator, the consistency of regional lung density measurements as estimated by EIT was validated to assess the feasibility of its use in intensive care medicine. There were significant differences in regional lung densities recorded in the supine position between normal lungs and diseased lungs associated with pneumonia, atelectasis and pleural effusion (normal; 240 ± 71.7 kg m(-3), pneumonia; 306 ± 38.6 kg m(-3), atelectasis; 497 ± 130 kg m(-3), pleural effusion; 467 ± 113 kg m(-3): Steel-Dwass test, p < 0.05). In addition, in order to compare lung density with CT image pixels, the image resolution of CT images, which was originally 512 × 512 pixels, was changed to 16 × 16 pixels to match that of the EIT images. The results of CT and EIT images from five patients in an intensive care unit showed a correlation coefficient of 0.66 ± 0.13 between the CT values (HU) and the lung density values (kg m(-3)) obtained from EIT. These results indicate that it may be possible to obtain a quantitative value for regional lung density using EIT.

Can pleural adenosine deaminase (ADA) levels in pleural tuberculosis predict the presence of pulmonary tuberculosis? A CT analysis.

PubMed

Koh, Myung Je; Lee, In Jae; Kim, Joo-Hee

2016-06-01

To assess the relationship between imaging features of pulmonary tuberculosis at computed tomography (CT) and adenosine deaminase (ADA) values via pleural fluid analysis in patients with pleural tuberculosis. This retrospective study enrolled 60 patients who underwent fluid analysis for ADA and chest CT and were diagnosed with tuberculosis by culture or polymerase chain reaction of pleural fluid and sputum. The presence of centrilobular nodules, consolidation, cavitation, and mediastinal lymphadenopathy at CT were evaluated. The relationship between ADA values and the pattern of pulmonary involvement of tuberculosis was analysed. Pulmonary involvement was seen in 42 of the 60 patients. A centrilobular nodular pattern was seen in 37 and consolidation in 22. In 17 patients, both findings were identified. A centrilobular nodular pattern was more common than consolidation or cavitary lesions. When ADA values were high, pulmonary involvement was more frequent (p=0.002). Comparing low and high ADA groups using an obtained cut-off value of 80 IU/l, the high group had more frequent pulmonary involvement (p<0.001). Patients with tuberculous pleurisy who had high ADA values had a higher probability of manifesting pulmonary tuberculosis. High ADA values may help predict contagious pleuroparenchymal tuberculosis. The most common pulmonary involvement of tuberculous pleurisy showed a centrilobular nodular pattern. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Clinical significance of FDG-PET/CT at the postoperative surveillance in the breast cancer patients.

PubMed

Jung, Na Young; Yoo, Ie Ryung; Kang, Bong Joo; Kim, Sung Hun; Chae, Byung Joo; Seo, Ye Young

2016-01-01

We evaluated the clinical role of [(18)F]-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) compared with conventional imaging (CI) to detect locoregional recurrence or distant metastasis during postoperative surveillance of patients with breast cancer. We included 1,819 examinations of 1,161 patients, who underwent FDG-PET/CT and CI, including mammography, breast ultrasound, whole-body bone scintigraphy, and chest radiography for postoperative surveillance. All patients had a history of surgery with or without adjuvant treatment due to more than stage II breast cancer between November 2003 and November 2009. We evaluated the diagnostic performance of CI, FDG-PET/CT, and combined CI and FDG-PET/CT for detecting locoregional recurrence, distant metastasis, and incidental cancer. We also analyzed false-positive and false-negative results in both FDG-PET/CT and CI. Sensitivity, specificity, positive predictive value, and negative predictive value of CI were 75.4, 98.7, 93.4, and 94.3 %. Those of FDG-PET/CT were 97.5, 98.8, 95.4, and 99.4 %. Those of the combined results were 98.6, 98.2, 96.7, and 99.7 %. Sensitivity of FDG-PET/CT was significantly higher than that of CI (P < 0.05). Sensitivity of combined CI and FDG-PET/CT results improved, but they were not significantly different from those of FDG-PET/CT alone (P = 0.43). Seventeen false-positive and nine false-negative cases were detected with FDG-PET/CT, and 19 false-positive and 88 false-negative cases were detected with CI. FDG-PET/CT is considered as an acceptable diagnostic imaging modality for postoperative surveillance of patients with breast cancer.

Diagnostic test accuracy study of 18F-sodium fluoride PET/CT, 99mTc-labelled diphosphonate SPECT/CT, and planar bone scintigraphy for diagnosis of bone metastases in newly diagnosed, high-risk prostate cancer

PubMed Central

Fonager, Randi F; Zacho, Helle D; Langkilde, Niels C; Fledelius, Joan; Ejlersen, June A; Haarmark, Christian; Hendel, Helle W; Lange, Mine Benedicte; Jochumsen, Mads R; Mortensen, Jesper C; Petersen, Lars J

2017-01-01

The aim of this study was to prospectively compare planar, bone scan (BS) versus SPECT/CT and NaF PET/CT in detecting bone metastases in prostate cancer. Thirty-seven consecutive, newly diagnosed, prostate cancer patients with prostate specific antigen (PSA) levels ≥ 50 ng/mL and who were considered eligible for androgen-deprivation therapy (ADT) were included in this study. BS, SPECT/CT, and NaF PET/CT, were performed prior to treatment and were repeated after six months of ADT. Baseline images from each index test were independently read by two experienced readers. The reference standard was based on a consensus decision made by a multidisciplinary team on the basis of baseline and follow-up images of the index tests, the findings of the baseline index tests by the experienced readers, and any available imaging, biochemical, and clinical data, including the response to ADT. Twenty-seven (73%) of the 37 patients had bone metastases according to the reference standard. The sensitivities for BS, SPECT/CT and NaF PET/CT were 78%, 89%, and 89%, respectively, and the specificities were 90%, 100%, and 90%, respectively. The positive predictive values of BS, SPECT/CT and NaF PET/CT were 96%, 100%, and 96%, respectively, and the negative predictive values were 60%, 77% and 75%, respectively. No statistically significant difference among the three imaging modalities was observed. All three imaging modalities showed high sensitivity and specificity. NaF PET/CT and SPECT/CT showed numerically improved, but not statistically superior, sensitivity compared with BS in this limited and selected patient cohort. PMID:29181269

Image registration and analysis for quantitative myocardial perfusion: application to dynamic circular cardiac CT.

PubMed

Isola, A A; Schmitt, H; van Stevendaal, U; Begemann, P G; Coulon, P; Boussel, L; Grass, M

2011-09-21

Large area detector computed tomography systems with fast rotating gantries enable volumetric dynamic cardiac perfusion studies. Prospectively, ECG-triggered acquisitions limit the data acquisition to a predefined cardiac phase and thereby reduce x-ray dose and limit motion artefacts. Even in the case of highly accurate prospective triggering and stable heart rate, spatial misalignment of the cardiac volumes acquired and reconstructed per cardiac cycle may occur due to small motion pattern variations from cycle to cycle. These misalignments reduce the accuracy of the quantitative analysis of myocardial perfusion parameters on a per voxel basis. An image-based solution to this problem is elastic 3D image registration of dynamic volume sequences with variable contrast, as it is introduced in this contribution. After circular cone-beam CT reconstruction of cardiac volumes covering large areas of the myocardial tissue, the complete series is aligned with respect to a chosen reference volume. The results of the registration process and the perfusion analysis with and without registration are evaluated quantitatively in this paper. The spatial alignment leads to improved quantification of myocardial perfusion for three different pig data sets.

Comparison of [68Ga]Ga-PSMA-11 PET/CT with [18F]NaF PET/CT in the evaluation of bone metastases in metastatic prostate cancer patients prior to radionuclide therapy.

PubMed

Uprimny, Christian; Svirydenka, Anna; Fritz, Josef; Kroiss, Alexander Stephan; Nilica, Bernhard; Decristoforo, Clemens; Haubner, Roland; von Guggenberg, Elisabeth; Buxbaum, Sabine; Horninger, Wolfgang; Virgolini, Irene Johanna

2018-05-16

The purpose of this study was to investigate the diagnostic performance of 68 Ga-PSMA-11 PET/CT in the evaluation of bone metastases in metastatic prostate cancer (PC) patients scheduled for radionuclide therapy in comparison to [ 18 F]sodium fluoride ( 18 F-NaF) PET/CT. Sixteen metastatic PC patients with known skeletal metastases, who underwent both 68 Ga-PSMA-11 PET/CT and 18 F-NaF PET/CT for assessment of metastatic burden prior to radionuclide therapy, were analysed retrospectively. The performance of both tracers was calculated on a lesion-based comparison. Intensity of tracer accumulation of pathologic bone lesions on 18 F-NaF PET and 68 Ga-PSMA-11 PET was measured with maximum standardized uptake values (SUV max ) and compared to background activity of normal bone. In addition, SUV max values of PET-positive bone lesions were analysed with respect to morphologic characteristics on CT. Bone metastases were either confirmed by CT or follow-up PET scan. In contrast to 468 PET-positive lesions suggestive of bone metastases on 18 F-NaF PET, only 351 of the lesions were also judged positive on 68 Ga-PSMA-11 PET (75.0%). Intensity of tracer accumulation of pathologic skeletal lesions was significantly higher on 18 F-NaF PET compared to 68 Ga-PSMA-11 PET, showing a median SUV max of 27.0 and 6.0, respectively (p < 0.001). Background activity of normal bone was lower on 68 Ga-PSMA-11 PET, with a median SUV max of 1.0 in comparison to 2.7 on 18 F-NaF PET; however, tumour to background ratio was significantly higher on 18 F-NaF PET (9.8 versus 5.9 on 68 Ga-PSMA-11 PET; p = 0.042). Based on morphologic lesion characterisation on CT, 18 F-NaF PET revealed median SUV max values of 23.6 for osteosclerotic, 35.0 for osteolytic, and 19.0 for lesions not visible on CT, whereas on 68 Ga-PSMA-11 PET median SUV max values of 5.0 in osteosclerotic, 29.5 in osteolytic, and 7.5 in lesions not seen on CT were measured. Intensity of tracer accumulation between 18 F-NaF PET and 68 Ga-PSMA-11 PET was significantly higher in osteosclerotic (p < 0.001) and lesions not visible on CT (p = 0.012). In comparison to 68 Ga-PSMA-11 PET/CT, 18 F-NaF PET/CT detects a higher number of pathologic bone lesions in advanced stage PC patients scheduled for radionuclide therapy. Our data suggest that 68 Ga-PSMA-11 PET should be combined with 18 F-NaF PET in PC patients with skeletal metastases for restaging prior to initiation or modification of therapy.

Evaluation of a multitarget real-time PCR assay for detection of Bordetella species during a pertussis outbreak in New Hampshire in 2011.

PubMed

Gao, Fengxiang; Mahoney, Jennifer C; Daly, Elizabeth R; Lamothe, Wendy; Tullo, Daniel; Bean, Christine

2014-01-01

A multitarget real-time PCR assay with three targets, including insertion sequence 481 (IS481), IS1001, and an IS1001-like element, as well as pertussis toxin subunit S1 (ptxS1), for the detection of Bordetella species was evaluated during a pertussis outbreak. The sensitivity and specificity were 77 and 88% (PCR) and 66 and 100% (culture), respectively. All patients with an IS481 C(T) of <30 also tested positive by ptxS1 assay and were clinical pertussis cases. No patients with IS481 C(T) values of ≥40 tested positive by culture. Therefore, we recommend that culture be performed only for specimens with IS481 C(T) values of 30 ≤ CT <40.

Evaluation of a Multitarget Real-Time PCR Assay for Detection of Bordetella Species during a Pertussis Outbreak in New Hampshire in 2011

PubMed Central

Mahoney, Jennifer C.; Daly, Elizabeth R.; Lamothe, Wendy; Tullo, Daniel; Bean, Christine

2014-01-01

A multitarget real-time PCR assay with three targets, including insertion sequence 481 (IS481), IS1001, and an IS1001-like element, as well as pertussis toxin subunit S1 (ptxS1), for the detection of Bordetella species was evaluated during a pertussis outbreak. The sensitivity and specificity were 77 and 88% (PCR) and 66 and 100% (culture), respectively. All patients with an IS481 CT of <30 also tested positive by ptxS1 assay and were clinical pertussis cases. No patients with IS481 CT values of ≥40 tested positive by culture. Therefore, we recommend that culture be performed only for specimens with IS481 CT values of 30 ≤ CT <40. PMID:24131698

Prognosis estimation under the light of metabolic tumor parameters on initial FDG-PET/CT in patients with primary extranodal lymphoma

PubMed Central

Okuyucu, Kursat; Ozaydın, Sukru; Alagoz, Engin; Ozgur, Gokhan; Oysul, Fahrettin Guven; Ozmen, Ozlem; Tuncel, Murat; Ozturk, Mustafa; Arslan, Nuri

2016-01-01

Abstract Background Non-Hodgkin’s lymphomas arising from the tissues other than primary lymphatic organs are named primary extranodal lymphoma. Most of the studies evaluated metabolic tumor parameters in different organs and histopathologic variants of this disease generally for treatment response. We aimed to evaluate the prognostic value of metabolic tumor parameters derived from initial FDG-PET/CT in patients with a medley of primary extranodal lymphoma in this study. Patients and methods There were 67 patients with primary extranodal lymphoma for whom FDG-PET/CT was requested for primary staging. Quantitative PET/CT parameters: maximum standardized uptake value (SUVmax), average standardized uptake value (SUVmean), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were used to estimate disease-free survival and overall survival. Results SUVmean, MTV and TLG were found statistically significant after multivariate analysis. SUVmean remained significant after ROC curve analysis. Sensitivity and specificity were calculated as 88% and 64%, respectively, when the cut-off value of SUVmean was chosen as 5.15. After the investigation of primary presentation sites and histo-pathological variants according to recurrence, there is no difference amongst the variants. Primary site of extranodal lymphomas however, is statistically important (p = 0.014). Testis and central nervous system lymphomas have higher recurrence rate (62.5%, 73%, respectively). Conclusions High SUVmean, MTV and TLG values obtained from primary staging FDG-PET/CT are potential risk factors for both disease-free survival and overall survival in primary extranodal lymphoma. SUVmean is the most significant one amongst them for estimating recurrence/metastasis. PMID:27904443

Vitamin B12 effects on chlorinated methanes-degrading microcosms: Dual isotope and metabolically active microbial populations assessment.

PubMed

Rodríguez-Fernández, Diana; Torrentó, Clara; Guivernau, Miriam; Viñas, Marc; Hunkeler, Daniel; Soler, Albert; Domènech, Cristina; Rosell, Mònica

2018-04-15

Field-derived anoxic microcosms were used to characterize chloroform (CF) and carbon tetrachloride (CT) natural attenuation to compare it with biostimulation scenarios in which vitamin B 12 was added (B 12 /pollutant ratio of 0.01 and 0.1) by means of by-products, carbon and chlorine compound-specific stable-isotope analysis, and the active microbial community through 16S rRNA MiSeq high-throughput sequencing. Autoclaved slurry controls discarded abiotic degradation processes. B 12 catalyzed CF and CT biodegradation without the accumulation of dichloromethane, carbon disulphide, or CF. The carbon isotopic fractionation value of CF (ƐC CF ) with B 12 was -14±4‰, and the value for chlorine (ƐCl CF ) was -2.4±0.4‰. The carbon isotopic fractionation values of CT (ƐC CT ) were -16±6 with B 12 , and -13±2‰ without B 12 ; and the chlorine isotopic fractionation values of CT (ƐCl CT ) were -6±3 and -4±2‰, respectively. Acidovorax, Ancylobacter, and Pseudomonas were the most metabolically active genera, whereas Dehalobacter and Desulfitobacterium were below 0.1% of relative abundance. The dual C-Cl element isotope slope (Λ=Δδ 13 C/Δδ 37 Cl) for CF biodegradation (only detected with B 12 , 7±1) was similar to that reported for CF reduction by Fe(0) (8±2). Several reductive pathways might be competing in the tested CT scenarios, as evidenced by the lack of CF accumulation when B 12 was added, which might be linked to a major activity of Pseudomonas stutzeri; by different chlorine apparent kinetic isotope effect values and Λ which was statistically different with and without B 12 (5±1 vs 6.1±0.5), respectively. Thus, positive B 12 effects such as CT and CF degradation catalyst were quantified for the first time in isotopic terms, and confirmed with the major activity of species potentially capable of their degradation. Moreover, the indirect benefits of B 12 on the degradation of chlorinated ethenes were proved, creating a basis for remediation strategies in multi-contaminant polluted sites. Copyright © 2017 Elsevier B.V. All rights reserved.

Mid-Ventilation Concept for Mobile Pulmonary Tumors: Internal Tumor Trajectory Versus Selective Reconstruction of Four-Dimensional Computed Tomography Frames Based on External Breathing Motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guckenberger, Matthias; Wilbert, Juergen; Krieger, Thomas

2009-06-01

Purpose: To evaluate the accuracy of direct reconstruction of mid-ventilation and peak-phase four-dimensional (4D) computed tomography (CT) frames based on the external breathing signal. Methods and Materials: For 11 patients with 15 pulmonary targets, a respiration-correlated CT study (4D CT) was acquired for treatment planning. After retrospective time-based sorting of raw projection data and reconstruction of eight CT frames equally distributed over the breathing cycle, mean tumor position (P{sub mean}), mid-ventilation frame, and breathing motion were evaluated based on the internal tumor trajectory. Analysis of the external breathing signal (pressure sensor around abdomen) with amplitude-based sorting of projections was performedmore » for direct reconstruction of the mid-ventilation frame and frames at peak phases of the breathing cycle. Results: On the basis of the eight 4D CT frames equally spaced in time, tumor motion was largest in the craniocaudal direction, with 12 {+-} 7 mm on average. Tumor motion between the two frames reconstructed at peak phases was not different in the craniocaudal and anterior-posterior directions but was systematically smaller in the left-right direction by 1 mm on average. The 3-dimensional distance between P{sub mean} and the tumor position in the mid-ventilation frame based on the internal tumor trajectory was 1.2 {+-} 1 mm. Reconstruction of the mid-ventilation frame at the mean amplitude position of the external breathing signal resulted in tumor positions 2.0 {+-} 1.1 mm distant from P{sub mean}. Breathing-induced motion artifacts in mid-ventilation frames caused negligible changes in tumor volume and shape. Conclusions: Direct reconstruction of the mid-ventilation frame and frames at peak phases based on the external breathing signal was reliable. This makes the reconstruction of only three 4D CT frames sufficient for application of the mid-ventilation technique in clinical practice.« less

Cadaveric study validating in vitro monitoring techniques to measure the failure mechanism of glenoid implants against clinical CT.

PubMed

Junaid, Sarah; Gregory, Thomas; Fetherston, Shirley; Emery, Roger; Amis, Andrew A; Hansen, Ulrich

2018-03-23

Definite glenoid implant loosening is identifiable on radiographs, however, identifying early loosening still eludes clinicians. Methods to monitor glenoid loosening in vitro have not been validated to clinical imaging. This study investigates the correlation between in vitro measures and CT images. Ten cadaveric scapulae were implanted with a pegged glenoid implant and fatigue tested to failure. Each scapulae were cyclically loaded superiorly and CT scanned every 20,000 cycles until failure to monitor progressive radiolucent lines. Superior and inferior rim displacements were also measured. A finite element (FE) model of one scapula was used to analyze the interfacial stresses at the implant/cement and cement/bone interfaces. All ten implants failed inferiorly at the implant-cement interface, two also failed at the cement-bone interface inferiorly, and three showed superior failure. Failure occurred at of 80,966 ± 53,729 (mean ± SD) cycles. CT scans confirmed failure of the fixation, and in most cases, was observed either before or with visual failure. Significant correlations were found between inferior rim displacement, vertical head displacement and failure of the glenoid implant. The FE model showed peak tensile stresses inferiorly and high compressive stresses superiorly, corroborating experimental findings. In vitro monitoring methods correlated to failure progression in clinical CT images possibly indicating its capacity to detect loosening earlier for earlier clinical intervention if needed. Its use in detecting failure non-destructively for implant development and testing is also valuable. The study highlights failure at the implant-cement interface and early signs of failure are identifiable in CT images. © 2018 The Authors. Journal of Orthopaedic Research ® Published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 9999:XX-XX, 2018. © 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society.

SU-E-T-797: Variations of Cardiac Dose at Different Respiratory Status in CyberKnife M6â„¢ Treatment Plans for Accelerated Partial Breast Irradiation (APBI)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, S; Shang, C; Evans, G

2015-06-15

Purpose: Cyberknife robotic assisted radiation delivery has become a choice for accelerated breast RT, while a slightly increased cardiac dose has been reported. The dose dynamics throughout the respiration cycle has scarcely been explored. This study was designed to investigate the dose changes at each respiratory phase or status during respiration cycle. Methods: Six patients with 4DCT studies and six patients with a pair of free-breathing and deep breath-hold CT sets were used for dosimetry comparisons. 4DCT sets were obtained by Siemens™ CT and its respiratory gating system, comprising of 8 phases. Standard APBI plan at 340 cGy was donemore » per fraction per NSABP B-39/RTOG 0413 and modulated with Cyberknife M6™ on MultiPlan™5.1.2. For the purpose of this study, the tumor volume was outlined in the media-lower quadrant of the left breast. Results: Except for D5cc in plans with 4DCT, cardiac doses are significantly different between respiratory phases in well inhaled breathing phases, and more significantly in plans with BH CT. Mean cardiac doses in 100% inhalation phase were often found to be 5–15% (p< 0.02) less than those in other phases. Conclusion: Although ineligible cardiac doses are noted in APBI plans using 4D free-breathing CT and instantaneous free breathing CT series, a reduction in cardiac dose was seen for the well-inhaled phases. This provides practical guidance for cardiac dose reduction applicable with CK M6 APBR.« less

Quantitative CT characterization of pediatric lung development using routine clinical imaging

PubMed Central

Stein, Jill M.; Walkup, Laura L.; Brody, Alan S.; Fleck, Robert J.

2016-01-01

Background The use of quantitative CT analysis in children is limited by lack of normal values of lung parenchymal attenuation. These characteristics are important because normal lung development yields significant parenchymal attenuation changes as children age. Objective To perform quantitative characterization of normal pediatric lung parenchymal X-ray CT attenuation under routine clinical conditions in order to establish a baseline comparison to that seen in pathological lung conditions. Materials and methods We conducted a retrospective query of normal CT chest examinations in children ages 0–7 years from 2004 to 2014 using standard clinical protocol. During these examinations semi-automated lung parenchymal segmentation was performed to measure lung volume and mean lung attenuation. Results We analyzed 42 CT examinations in 39 children, ages 3 days to 83 months (mean ± standard deviation [SD] = 42±27 months). Lung volume ranged 0.10–1.72 liters (L). Mean lung attenuation was much higher in children younger than 12 months, with values as high as −380 Hounsfield units (HU) in neonates (lung volume 0.10 L). Lung volume decreased to approximately −650 HU by age 2 years (lung volume 0.47 L), with subsequently slower exponential decrease toward a relatively constant value of −860 HU as age and lung volume increased. Conclusion Normal lung parenchymal X-ray CT attenuation decreases with increasing lung volume and age; lung attenuation decreases rapidly in the first 2 years of age and more slowly thereafter. This change in normal lung attenuation should be taken into account as quantitative CT methods are translated to pediatric pulmonary imaging. PMID:27576458

Cranial CT with adaptive statistical iterative reconstruction: improved image quality with concomitant radiation dose reduction.

PubMed

Rapalino, O; Kamalian, Shervin; Kamalian, Shahmir; Payabvash, S; Souza, L C S; Zhang, D; Mukta, J; Sahani, D V; Lev, M H; Pomerantz, S R

2012-04-01

To safeguard patient health, there is great interest in CT radiation-dose reduction. The purpose of this study was to evaluate the impact of an iterative-reconstruction algorithm, ASIR, on image-quality measures in reduced-dose head CT scans for adult patients. Using a 64-section scanner, we analyzed 100 reduced-dose adult head CT scans at 6 predefined levels of ASIR blended with FBP reconstruction. These scans were compared with 50 CT scans previously obtained at a higher routine dose without ASIR reconstruction. SNR and CNR were computed from Hounsfield unit measurements of normal GM and WM of brain parenchyma. A blinded qualitative analysis was performed in 10 lower-dose CT datasets compared with higher-dose ones without ASIR. Phantom data analysis was also performed. Lower-dose scans without ASIR had significantly lower mean GM and WM SNR (P = .003) and similar GM-WM CNR values compared with higher routine-dose scans. However, at ASIR levels of 20%-40%, there was no statistically significant difference in SNR, and at ASIR levels of ≥60%, the SNR values of the reduced-dose scans were significantly higher (P < .01). CNR values were also significantly higher at ASIR levels of ≥40% (P < .01). Blinded qualitative review demonstrated significant improvements in perceived image noise, artifacts, and GM-WM differentiation at ASIR levels ≥60% (P < .01). These results demonstrate that the use of ASIR in adult head CT scans reduces image noise and increases low-contrast resolution, while allowing lower radiation doses without affecting spatial resolution.

Evaluation of organ doses in CT examinations with an infant anthropomorphic phantom.

PubMed

Fujii, K; Akahane, K; Miyazaki, O; Horiuchi, T; Shimada, A; Nagmatsu, H; Yamauchi, M; Yamauchi-Kawaura, C; Kawasaki, T

2011-09-01

The aim of this study is to evaluate organ doses in infant CT examinations with multi-detector row CT scanners. Radiation doses were measured with radiophotoluminescence glass dosemeters set in various organ positions within a 1-y-old child anthropomorphic phantom and organ doses were evaluated from the measurement values. Doses for tissues or organs within the scan range were 28-36 mGy in an infant head CT, 3-11 mGy in a chest CT, 5-11 mGy in an abdominal-pelvic CT and 2-14 mGy in a cardiac CT. The doses varied by the differences in the types of CT scanners and scan parameters used at each medical facility. Compared with those for children of various ages, the doses in an infant CT protocol were found to be similar to or slightly smaller than those in a paediatric CT for 5- or 6-y-old children.

Relationships between serum PSA levels, Gleason scores and results of 68Ga-PSMAPET/CT in patients with recurrent prostate cancer.

PubMed

Sanli, Yasemin; Kuyumcu, Serkan; Sanli, Oner; Buyukkaya, Fikret; İribaş, Ayça; Alcin, Goksel; Darendeliler, Emin; Ozluk, Yasemin; Yildiz, Sevda Ozel; Turkmen, Cüneyt

2017-11-01

To investigate the relationship between serum PSA level, Gleason score of PCa and the outcomes of Ga 68 -PSMA PET/CT in patients with recurrent PCa. A total of 109 consecutive patients (median age 71 years; range 48-89 years) who had PSA recurrence after RP and/or hormonotherapy and/or radiotherapy were included in this study. Local recurrences, lymph node metastasis (pelvic, abdominal and/or supradiaphragmatic), bone metastases (oligometastatic/multimetastatic) and other metastatic sites (lung, liver, brain, etc) were documented. In 91(83.4%) patients at least one lesion characteristic for PCa was detected by 68 Ga-PSMA PET/CT. The median serum total PSA (tPSA) was 6.5 (0.2-640) ng/ml.There was a significant difference between 68 Ga-PSMA PET/CT positive and negative patients in terms of serum total PSA value. No statistical significance was found between positive and negative 68 Ga-PSMA PET/CT findings in terms of Gleason score. Local recurrence was detected in 56 patients. whereas lymph node metastases were demonstrated in 46 patients. Pelvic nodal disease was the most frequent presentation followed by abdominal and supradiaphragmaticnodal involvement. Bone metastases [oligometastasis, (n = 20); multimetastasis, (n = 35)⦌ were also detected in 55 patients. In the ROC analysis for the study cohort, the optimal cut-off value of total serum PSA was determined as 0.67 ng/ml for distinguishing between positive and negative 68 Ga-PSMA PET/CT images, with an area under curve of 0.952 (95% CI 0.911-0.993). 68 Ga-PSMA PET/CT was found to be an effective tool for the detection of recurrent PCa. Even though no relationship was detected between the GS and 68 Ga-PSMA PET/CT findings, serum total PSA values may be used for estimating the likelihood of positive 68 Ga-PSMA PET/CT results.

Accuracy of Dual-Energy Virtual Monochromatic CT Numbers: Comparison between the Single-Source Projection-Based and Dual-Source Image-Based Methods.

PubMed

Ueguchi, Takashi; Ogihara, Ryota; Yamada, Sachiko

2018-03-21

To investigate the accuracy of dual-energy virtual monochromatic computed tomography (CT) numbers obtained by two typical hardware and software implementations: the single-source projection-based method and the dual-source image-based method. A phantom with different tissue equivalent inserts was scanned with both single-source and dual-source scanners. A fast kVp-switching feature was used on the single-source scanner, whereas a tin filter was used on the dual-source scanner. Virtual monochromatic CT images of the phantom at energy levels of 60, 100, and 140 keV were obtained by both projection-based (on the single-source scanner) and image-based (on the dual-source scanner) methods. The accuracy of virtual monochromatic CT numbers for all inserts was assessed by comparing measured values to their corresponding true values. Linear regression analysis was performed to evaluate the dependency of measured CT numbers on tissue attenuation, method, and their interaction. Root mean square values of systematic error over all inserts at 60, 100, and 140 keV were approximately 53, 21, and 29 Hounsfield unit (HU) with the single-source projection-based method, and 46, 7, and 6 HU with the dual-source image-based method, respectively. Linear regression analysis revealed that the interaction between the attenuation and the method had a statistically significant effect on the measured CT numbers at 100 and 140 keV. There were attenuation-, method-, and energy level-dependent systematic errors in the measured virtual monochromatic CT numbers. CT number reproducibility was comparable between the two scanners, and CT numbers had better accuracy with the dual-source image-based method at 100 and 140 keV. Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Technical Note: Relation between dual-energy subtraction of CT images for electron density calibration and virtual monochromatic imaging.

PubMed

Saito, Masatoshi

2015-07-01

For accurate tissue inhomogeneity correction in radiotherapy treatment planning, the author previously proposed a simple conversion of the energy-subtracted computed tomography (CT) number to an electron density (ΔHU-ρe conversion), which provides a single linear relationship between ΔHU and ρe over a wide ρe range. The purpose of the present study was to reveal the relation between the ΔHU image for ρe calibration and a virtually monochromatic CT image by performing numerical analyses based on the basis material decomposition in dual-energy CT. The author determined the weighting factor, α0, of the ΔHU-ρe conversion through numerical analyses of the International Commission on Radiation Units and Measurements Report-46 human body tissues using their attenuation coefficients and given ρe values. Another weighting factor, α(E), for synthesizing a virtual monochromatic CT image from high- and low-kV CT images, was also calculated in the energy range of 0.03 < E < 5 MeV, assuming that cortical bone and water were the basis materials. The mass attenuation coefficients for these materials were obtained using the xcom photon cross sections database. The effective x-ray energies used to calculate the attenuation were chosen to imitate a dual-source CT scanner operated at 80-140 and 100-140 kV/Sn. The determined α0 values were 0.455 for 80-140 kV/Sn and 0.743 for 100-140 kV/Sn. These values coincided almost perfectly with the respective maximal points of the calculated α(E) curves located at approximately 1 MeV, in which the photon-matter interaction in human body tissues is exclusively the incoherent (Compton) scattering. The ΔHU image could be regarded substantially as a CT image acquired with monoenergetic 1-MeV photons, which provides a linear relationship between CT numbers and electron densities.

Estimating patient dose from CT exams that use automatic exposure control: Development and validation of methods to accurately estimate tube current values.

PubMed

McMillan, Kyle; Bostani, Maryam; Cagnon, Christopher H; Yu, Lifeng; Leng, Shuai; McCollough, Cynthia H; McNitt-Gray, Michael F

2017-08-01

The vast majority of body CT exams are performed with automatic exposure control (AEC), which adapts the mean tube current to the patient size and modulates the tube current either angularly, longitudinally or both. However, most radiation dose estimation tools are based on fixed tube current scans. Accurate estimates of patient dose from AEC scans require knowledge of the tube current values, which is usually unavailable. The purpose of this work was to develop and validate methods to accurately estimate the tube current values prescribed by one manufacturer's AEC system to enable accurate estimates of patient dose. Methods were developed that took into account available patient attenuation information, user selected image quality reference parameters and x-ray system limits to estimate tube current values for patient scans. Methods consistent with AAPM Report 220 were developed that used patient attenuation data that were: (a) supplied by the manufacturer in the CT localizer radiograph and (b) based on a simulated CT localizer radiograph derived from image data. For comparison, actual tube current values were extracted from the projection data of each patient. Validation of each approach was based on data collected from 40 pediatric and adult patients who received clinically indicated chest (n = 20) and abdomen/pelvis (n = 20) scans on a 64 slice multidetector row CT (Sensation 64, Siemens Healthcare, Forchheim, Germany). For each patient dataset, the following were collected with Institutional Review Board (IRB) approval: (a) projection data containing actual tube current values at each projection view, (b) CT localizer radiograph (topogram) and (c) reconstructed image data. Tube current values were estimated based on the actual topogram (actual-topo) as well as the simulated topogram based on image data (sim-topo). Each of these was compared to the actual tube current values from the patient scan. In addition, to assess the accuracy of each method in estimating patient organ doses, Monte Carlo simulations were performed by creating voxelized models of each patient, identifying key organs and incorporating tube current values into the simulations to estimate dose to the lungs and breasts (females only) for chest scans and the liver, kidney, and spleen for abdomen/pelvis scans. Organ doses from simulations using the actual tube current values were compared to those using each of the estimated tube current values (actual-topo and sim-topo). When compared to the actual tube current values, the average error for tube current values estimated from the actual topogram (actual-topo) and simulated topogram (sim-topo) was 3.9% and 5.8% respectively. For Monte Carlo simulations of chest CT exams using the actual tube current values and estimated tube current values (based on the actual-topo and sim-topo methods), the average differences for lung and breast doses ranged from 3.4% to 6.6%. For abdomen/pelvis exams, the average differences for liver, kidney, and spleen doses ranged from 4.2% to 5.3%. Strong agreement between organ doses estimated using actual and estimated tube current values provides validation of both methods for estimating tube current values based on data provided in the topogram or simulated from image data. © 2017 American Association of Physicists in Medicine.

(11)C-Choline PET/CT for restaging prostate cancer. Results from 4,426 scans in a single-centre patient series.

PubMed

Graziani, Tiziano; Ceci, Francesco; Castellucci, Paolo; Polverari, Giulia; Lima, Giacomo Maria; Lodi, Filippo; Morganti, Alessio Giuseppe; Ardizzoni, Andrea; Schiavina, Riccardo; Fanti, Stefano

2016-10-01

To evaluate (11)C-choline PET/CT as a diagnostic tool for restaging prostate cancer (PCa), in a large, homogeneous and clinically relevant population of patients with biochemical recurrence (BCR) of PCa after primary therapy. The secondary aim was to assess the best timing for performing (11)C-choline PET/CT during BCR. We retrospectively analysed 9,632 (11)C-choline PET/CT scans performed in our institution for restaging PCa from January 2007 to June 2015. The inclusion criteria were: (1) proven PCa radically treated with radical prostatectomy (RP) or with primary external beam radiotherapy (EBRT); (2) PSA serum values available; (3) proven BCR (PSA >0.2 ng/mL after RP or PSA >2 ng/mL above the nadir after primary EBRT with rising PSA levels). Finally, 3,203 patients with recurrent PCa matching all the inclusion criteria were retrospectively enrolled and 4,426 scans were analysed. Overall, 52.8 % of the (11)C-choline PET/CT scans (2,337/4,426) and 54.8 % of the patients (1,755/3,203) were positive. In 29.4 % of the scans, at least one distant finding was observed. The mean and median PSA values were, respectively, 4.9 and 2.1 ng/mL at the time of the scan (range 0.2 - 50 ng/mL). In our series, 995 scans were performed in patients with PSA levels between 1 and 2 ng/mL. In this subpopulation the positivity rate in the 995 scans was 44.7 %, with an incidence of distant findings of 19.2 % and an incidence of oligometastatic disease (one to three lesions) of 37.7 %. The absolute PSA value at the time of the scan and ongoing androgen deprivation therapy were associated with an increased probability of a positive (11)C-choline PET/CT scan (p < 0.0001). In the ROC analysis, a PSA value of 1.16 ng/mL was the optimal cut-off value. In patients with a PSA value <1.16 ng/mL, 26.8 % of 1,426 (11)C-choline PET/CT scans were positive, with oligometastatic disease in 84.7 % of positive scans. In a large cohort of patients, the feasibility of (11)C-choline PET/CT for detecting the sites of metastatic disease in PCa patients with BCR was confirmed. The PSA level was the main predictor of a positive scan with 1.16 ng/mL as the optimal cut-off value. In the majority of positive scans oligometastatic disease, potentially treatable with salvage therapies, was observed.

Semiautomated thyroid volumetry using 3D CT: prospective comparison with measurements obtained using 2D ultrasound, 2D CT, and water displacement method of specimen.

PubMed

Lee, Sun Jin; Chong, Semin; Kang, Kyung Ho; Hur, Joonho; Hong, Byung-Woo; Kim, Hyun Jung; Kim, Soo Jin

2014-11-01

The objective of our study was to measure thyroid volumes using semiautomated 3D CT and to compare the 3D CT volumes with volumes measured using 2D ultrasound, 2D CT, and the water displacement method. In 47 patients, 2D ultrasound volumes and 2D CT volumes of the thyroid gland were estimated using the ellipsoid volume formula, and 3D CT volumes were calculated using semiautomated reconstructive techniques. All volume data were compared with thyroid specimen volumes obtained using the water displacement method and were statistically analyzed using the one-way ANOVA, the Pearson correlation coefficient (R), linear regression, and the concordance correlation coefficient (CCC). The processing time of semiautomated 3D CT thyroid volumetry was measured. The paired mean differences ± SD between the three imaging-determined volumes and the specimen volumes were 0.8 ± 3.1 mL for 2D ultrasound, 4.0 ± 4.7 mL for 2D CT, and 0.2 ± 2.5 mL for 3D CT. A significant difference in the mean thyroid volume was found between 2D CT and specimen volumes (p = 0.016) compared with the other pairs (p = 0.937 for 2D ultrasound mean volume vs specimen mean volume, and p = 0.999 for 3D CT mean volume vs specimen mean volume). Between specimen volume and 2D ultrasound volume, specimen volume and 2D CT volume, and specimen volume and 3D CT volume, R values were 0.885, 0.724, and 0.929, respectively, and CCC values were 0.876, 0.598, and 0.925, respectively. The mean processing time of semiautomated 3D CT thyroid volumetry was 7.0 minutes. Thyroid volumes measured using 2D ultrasound or semiautomated 3D CT are substantially close to thyroid specimen volumes measured using the water displacement method. Semiautomated 3D CT thyroid volumetry can provide a more reliable measure of thyroid volume than 2D ultrasound.

[Clinical randomized controlled trial on the feasibility and validity of continuous blood purification during the early stage of severe burn].

PubMed

Liu, F; Huang, Z G; Peng, Y Z; Wu, J; He, W F; Yuan, Z Q; Zhang, J P; Luo, Q Z; Yan, H; Peng, D Z; Dang, Y M; Luo, G X

2016-03-01

To observe and primarily evaluate the feasibility and validity of continuous blood purification (CBP) during the early stage of severe burn. Forty-one patients with severe burn admitted to our ward from January 2013 to July 2015, conforming to the study criteria, were divided into conventional treatment group (CT, n=21) and blood purification group (BP, n=20) according to the random number table and patient's personal consent. Patients in group CT received CT conforming to the traditional resuscitation principle for severe burn, while patients in group BP received CT and blood purification treatment in the mode of continuous venous-venous hemodiafiltration in addition up to post injury hour (PIH) 72. On post injury day (PID) 1, 2, 3, the vital signs, volume of fluid input, and volume of the urine output were observed and recorded; femoral artery blood was drawn to determine lactate, bicarbonate radical, and base excess, and oxygen index was calculated. At PIH 12, 24, 48, 72, femoral vein blood was drawn to determine white cell count, platelet count, neutrophils, creatine kinase-MB, creatine kinase, lactic dehydrogenase, aspartate transaminase (AST), alanine aminotransferase (ALT), creatinine, urea nitrogen, and blood glucose (the ratio of AST to ALT was calculated). The incidence of infection, sepsis, and multiple organ dysfunction syndrome (MODS) and the mortality of patients were recorded during 2 months after injury. Data were processed with chi-square test, analysis of variance for repeated measurement, t test and Wilcoxon test, and the values of P were adjusted by Bonferroni. The observation was completed in the 41 patients without exclusion. (1) There were no statistically significant differences in vital signs, volume of fluid input, and volume of the urine output of patients between two groups on PID 1, 2, 3 (with t values from -1.64 to 1.48, P values above 0.05). (2) Compared with that in group CT, the level of lactate of patients in group BP declined significantly on PID 2 and 3 (with Z values respectively -2.37 and -2.46, P values below 0.05). Compared with those in group CT, the levels of bicarbonate radical and base excess of patients in group BP declined significantly on PID 3 (with t values both as -2.51, P values below 0.05). The oxygen index of patients in group BP on PID 3 was (370±98) mmHg (1 mmHg=0.133 kPa), which was significantly higher than that in group CT [(305±81) mmHg, t=2.27, P<0.05]. (3) There were no statistically significant differences in white cell count, platelet count, neutrophils, creatine kinase, lactic dehydrogenase, AST, ALT, and AST to ALT ratio of patients between two groups at PIH 12, 24, 48, 72 (with t values from -1.47 to 1.19, Z values from -1.58 to -0.03, P values above 0.05). At PIH 24, 48, 72, the levels of creatine kinase-MB and blood glucose of patients in group BP were respectively (81±43), (55±34), (58±40) U/L and (7.9±2.0), (6.7±0.9), (6.9±1.8) mmol/L, which were significantly lower than those in group CT [(179±184), (124±71), (103±57) U/L and (10.1±3.8), (9.1±2.4), (8.8±4.1) mmol/L, with Z values from -3.73 to -2.02, P<0.05 or P<0.01]. Compared with those of patients in group CT, creatinine at PIH 48 and urea nitrogen at PIH 24, 48, 72 were obviously lower in group BP (with t values from -4.23 to -2.44, P<0.05 or P<0.01). (4) During the two months after injury, the infection rate of patients in group BP was 60.0% (12/20), which was significantly lower than that in group CT [95.2% (20/21), χ(2)=5.51, P<0.05]. The incidence of sepsis and MODS and the mortality of patients in group BP were all lower than those in group CT, but there were no statistically significant differences (with χ(2) values from 0.22 to 2.93, P values above 0.05). Conducting CBP in the early stage of severe burn is safe and feasible, which does not obviously affect the vital signs, volumes of fluid input and urine output, or platelet count of patients, additionally, it could help protect the function of vital organs, eliminate stress hyperglycemia, and reduce infection rate. Clinical trial registration Chinese Clinical Trial Registry, ChiCTR-TRC-12002616.

WE-FG-207B-04: Noise Suppression for Energy-Resolved CT Via Variance Weighted Non-Local Filtration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harms, J; Zhu, L

Purpose: The photon starvation problem is exacerbated in energy-resolved CT, since the detected photons are shared by multiple energy channels. Using pixel similarity-based non-local filtration, we aim to produce accurate and high-resolution energy-resolved CT images with significantly reduced noise. Methods: Averaging CT images reconstructed from different energy channels reduces noise at the price of losing spectral information, while conventional denoising techniques inevitably degrade image resolution. Inspired by the fact that CT images of the same object at different energies share the same structures, we aim to reduce noise of energy-resolved CT by averaging only pixels of similar materials - amore » non-local filtration technique. For each CT image, an empirical exponential model is used to calculate the material similarity between two pixels based on their CT values and the similarity values are organized in a matrix form. A final similarity matrix is generated by averaging these similarity matrices, with weights inversely proportional to the estimated total noise variance in the sinogram of different energy channels. Noise suppression is achieved for each energy channel via multiplying the image vector by the similarity matrix. Results: Multiple scans on a tabletop CT system are used to simulate 6-channel energy-resolved CT, with energies ranging from 75 to 125 kVp. On a low-dose acquisition at 15 mA of the Catphan©600 phantom, our method achieves the same image spatial resolution as a high-dose scan at 80 mA with a noise standard deviation (STD) lower by a factor of >2. Compared with another non-local noise suppression algorithm (ndiNLM), the proposed algorithms obtains images with substantially improved resolution at the same level of noise reduction. Conclusion: We propose a noise-suppression method for energy-resolved CT. Our method takes full advantage of the additional structural information provided by energy-resolved CT and preserves image values at each energy level. Research reported in this publication was supported by the National Institute Of Biomedical Imaging And Bioengineering of the National Institutes of Health under Award Number R21EB019597. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.« less

A method of semi-quantifying β-AP in brain PET-CT 11C-PiB images.

PubMed

Jiang, Jiehui; Lin, Xiaoman; Wen, Junlin; Huang, Zhemin; Yan, Zhuangzhi

2014-01-01

Alzheimer's disease (AD) is a common health problem for elderly populations. Positron emission tomography-computed tomography (PET-CT)11C-PiB for beta-P (amyloid-β peptide, β-AP) imaging is an advanced method to diagnose AD in early stage. However, in practice radiologists lack a standardized value to semi-quantify β-AP. This paper proposes such a standardized value: SVβ-AP. This standardized value measures the mean ratio between the dimension of β-AP areas in PET and CT images. A computer aided diagnosis approach is also proposed to achieve SVβ-AP. A simulation experiment was carried out to pre-test the technical feasibility of the CAD approach and SVβ-AP. The experiment results showed that it is technically feasible.

Analysis of Diagnostic Findings From the European Mobile Laboratory in Guéckédou, Guinea, March 2014 Through March 2015.

PubMed

Kerber, Romy; Krumkamp, Ralf; Diallo, Boubacar; Jaeger, Anna; Rudolf, Martin; Lanini, Simone; Bore, Joseph Akoi; Koundouno, Fara Raymond; Becker-Ziaja, Beate; Fleischmann, Erna; Stoecker, Kilian; Meschi, Silvia; Mély, Stéphane; Newman, Edmund N C; Carletti, Fabrizio; Portmann, Jasmine; Korva, Misa; Wolff, Svenja; Molkenthin, Peter; Kis, Zoltan; Kelterbaum, Anne; Bocquin, Anne; Strecker, Thomas; Fizet, Alexandra; Castilletti, Concetta; Schudt, Gordian; Ottowell, Lisa; Kurth, Andreas; Atkinson, Barry; Badusche, Marlis; Cannas, Angela; Pallasch, Elisa; Bosworth, Andrew; Yue, Constanze; Pályi, Bernadett; Ellerbrok, Heinz; Kohl, Claudia; Oestereich, Lisa; Logue, Christopher H; Lüdtke, Anja; Richter, Martin; Ngabo, Didier; Borremans, Benny; Becker, Dirk; Gryseels, Sophie; Abdellati, Saïd; Vermoesen, Tine; Kuisma, Eeva; Kraus, Annette; Liedigk, Britta; Maes, Piet; Thom, Ruth; Duraffour, Sophie; Diederich, Sandra; Hinzmann, Julia; Afrough, Babak; Repits, Johanna; Mertens, Marc; Vitoriano, Inês; Bah, Amadou; Sachse, Andreas; Boettcher, Jan Peter; Wurr, Stephanie; Bockholt, Sabrina; Nitsche, Andreas; Županc, Tatjana Avšič; Strasser, Marc; Ippolito, Giuseppe; Becker, Stephan; Raoul, Herve; Carroll, Miles W; De Clerck, Hilde; Van Herp, Michel; Sprecher, Armand; Koivogui, Lamine; Magassouba, N'Faly; Keïta, Sakoba; Drury, Patrick; Gurry, Cèline; Formenty, Pierre; May, Jürgen; Gabriel, Martin; Wölfel, Roman; Günther, Stephan; Di Caro, Antonino

2016-10-15

 A unit of the European Mobile Laboratory (EMLab) consortium was deployed to the Ebola virus disease (EVD) treatment unit in Guéckédou, Guinea, from March 2014 through March 2015.  The unit diagnosed EVD and malaria, using the RealStar Filovirus Screen reverse transcription-polymerase chain reaction (RT-PCR) kit and a malaria rapid diagnostic test, respectively.  The cleaned EMLab database comprised 4719 samples from 2741 cases of suspected EVD from Guinea. EVD was diagnosed in 1231 of 2178 hospitalized patients (57%) and in 281 of 563 who died in the community (50%). Children aged <15 years had the highest proportion of Ebola virus-malaria parasite coinfections. The case-fatality ratio was high in patients aged <5 years (80%) and those aged >74 years (90%) and low in patients aged 10-19 years (40%). On admission, RT-PCR analysis of blood specimens from patients who died in the hospital yielded a lower median cycle threshold (Ct) than analysis of blood specimens from survivors (18.1 vs 23.2). Individuals who died in the community had a median Ct of 21.5 for throat swabs. Multivariate logistic regression on 1047 data sets revealed that low Ct values, ages of <5 and ≥45 years, and, among children aged 5-14 years, malaria parasite coinfection were independent determinants of a poor EVD outcome.  Virus load, age, and malaria parasite coinfection play a role in the outcome of EVD. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.

Analysis of Diagnostic Findings From the European Mobile Laboratory in Guéckédou, Guinea, March 2014 Through March 2015

PubMed Central

Kerber, Romy; Krumkamp, Ralf; Diallo, Boubacar; Jaeger, Anna; Rudolf, Martin; Lanini, Simone; Bore, Joseph Akoi; Koundouno, Fara Raymond; Becker-Ziaja, Beate; Fleischmann, Erna; Stoecker, Kilian; Meschi, Silvia; Mély, Stéphane; Newman, Edmund N. C.; Carletti, Fabrizio; Portmann, Jasmine; Korva, Misa; Wolff, Svenja; Molkenthin, Peter; Kis, Zoltan; Kelterbaum, Anne; Bocquin, Anne; Strecker, Thomas; Fizet, Alexandra; Castilletti, Concetta; Schudt, Gordian; Ottowell, Lisa; Kurth, Andreas; Atkinson, Barry; Badusche, Marlis; Cannas, Angela; Pallasch, Elisa; Bosworth, Andrew; Yue, Constanze; Pályi, Bernadett; Ellerbrok, Heinz; Kohl, Claudia; Oestereich, Lisa; Logue, Christopher H.; Lüdtke, Anja; Richter, Martin; Ngabo, Didier; Borremans, Benny; Becker, Dirk; Gryseels, Sophie; Abdellati, Saïd; Vermoesen, Tine; Kuisma, Eeva; Kraus, Annette; Liedigk, Britta; Maes, Piet; Thom, Ruth; Duraffour, Sophie; Diederich, Sandra; Hinzmann, Julia; Afrough, Babak; Repits, Johanna; Mertens, Marc; Vitoriano, Inês; Bah, Amadou; Sachse, Andreas; Boettcher, Jan Peter; Wurr, Stephanie; Bockholt, Sabrina; Nitsche, Andreas; Županc, Tatjana Avšič; Strasser, Marc; Ippolito, Giuseppe; Becker, Stephan; Raoul, Herve; Carroll, Miles W.; De Clerck, Hilde; Van Herp, Michel; Sprecher, Armand; Koivogui, Lamine; Magassouba, N'Faly; Keïta, Sakoba; Drury, Patrick; Gurry, Cèline; Formenty, Pierre; May, Jürgen; Gabriel, Martin; Wölfel, Roman; Günther, Stephan; Di Caro, Antonino

2016-01-01

Background. A unit of the European Mobile Laboratory (EMLab) consortium was deployed to the Ebola virus disease (EVD) treatment unit in Guéckédou, Guinea, from March 2014 through March 2015. Methods. The unit diagnosed EVD and malaria, using the RealStar Filovirus Screen reverse transcription–polymerase chain reaction (RT-PCR) kit and a malaria rapid diagnostic test, respectively. Results. The cleaned EMLab database comprised 4719 samples from 2741 cases of suspected EVD from Guinea. EVD was diagnosed in 1231 of 2178 hospitalized patients (57%) and in 281 of 563 who died in the community (50%). Children aged <15 years had the highest proportion of Ebola virus–malaria parasite coinfections. The case-fatality ratio was high in patients aged <5 years (80%) and those aged >74 years (90%) and low in patients aged 10–19 years (40%). On admission, RT-PCR analysis of blood specimens from patients who died in the hospital yielded a lower median cycle threshold (Ct) than analysis of blood specimens from survivors (18.1 vs 23.2). Individuals who died in the community had a median Ct of 21.5 for throat swabs. Multivariate logistic regression on 1047 data sets revealed that low Ct values, ages of <5 and ≥45 years, and, among children aged 5–14 years, malaria parasite coinfection were independent determinants of a poor EVD outcome. Conclusions. Virus load, age, and malaria parasite coinfection play a role in the outcome of EVD. PMID:27638946

Patients with pathological stage N2 rectal cancer treated with early adjuvant chemotherapy have a lower treatment failure rate.

PubMed

Feng, Yan-Ru; Jin, Jing; Ren, Hua; Wang, Xin; Wang, Shu-Lian; Wang, Wei-Hu; Song, Yong-Wen; Liu, Yue-Ping; Tang, Yuan; Li, Ning; Liu, Xin-Fan; Fang, Hui; Yu, Zi-Hao; Li, Ye-Xiong

2017-03-09

In this era of oxaliplatin-based adjuvant therapy, the optimal sequence in which chemoradiotherapy should be administered for pathological stage N2 rectal cancer is unknown. The aim of this study was to investigate this sequence. In the primary adjuvant concurrent chemoradiotherapy (A-CRT) group (n = 71), postoperative concurrent chemoradiotherapy was administered before adjuvant chemotherapy. In the primary adjuvant chemotherapy (A-CT) group (n = 43), postoperative concurrent chemoradiotherapy was administered during or after adjuvant chemotherapy. Postoperative radiotherapy comprised 45-50.4 Gy in 25-28 fractions. Concurrent chemotherapy comprised two cycles of oral capecitabine (1,600 mg/m 2 ) on days 1-14 and 22-35. Patients receiving adjuvant chemotherapy with four or more cycles of XELOX (oxaliplatin plus capecitabine) or eight or more cycles of FOLFOX (fluorouracil, leucovorin, and oxaliplatin) were included. Between June 2005 and December 2013, data for 114 qualified rectal cancer patients were analyzed. The percentages of patients in whom treatment failed in the A-CRT and A-CT groups were 33.8% and 16.3%, respectively (p = 0.042). More patients had distant metastases in the A-CRT group than in the A-CT group (32.4% vs. 14.3%, p = 0.028). Multivariate analysis indicated that the sequence in which chemoradiotherapy was administered (A-CT vs. A-CRT) was an independent prognostic factor for both estimated disease-free survival [hazard ratio (HR) 0.345, 95% confidence interval (CI) 0.137-0.868, p = 0.024] and estimated distant metastasis-free survival (HR 0.366, 95% CI 0.143-0.938, p = 0.036). In pathological stage N2 rectal cancer patients, administering adjuvant chemotherapy before chemoradiotherapy led to a lower rate of treatment failure, especially with respect to distant metastasis. Adjuvant chemotherapy prescribed as early as possible might benefit this cohort of patients in this era of oxaliplatin-based adjuvant therapy.

CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma: specific technical aspects and clinical results.

PubMed

Sommer, C M; Lemm, G; Hohenstein, E; Bellemann, N; Stampfl, U; Goezen, A S; Rassweiler, J; Kauczor, H U; Radeleff, B A; Pereira, P L

2013-06-01

This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. We included 22 consecutive patients (3 women; age 74.2 ± 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 ± 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 ± 13.6 min and 43.7 ± 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 ± 8.8 months, local recurrence-free survival was 14.4 ± 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 ± 16.6 ml/min/1.73 m(2) before RF ablation vs. 47.2 ± 11.9 ml/min/1.73 m(2) after RF ablation; not significant). CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

The Swedish new variant of Chlamydia trachomatis: genome sequence, morphology, cell tropism and phenotypic characterization

PubMed Central

Unemo, Magnus; Seth-Smith, Helena M. B.; Cutcliffe, Lesley T.; Skilton, Rachel J.; Barlow, David; Goulding, David; Persson, Kenneth; Harris, Simon R.; Kelly, Anne; Bjartling, Carina; Fredlund, Hans; Olcén, Per; Thomson, Nicholas R.; Clarke, Ian N.

2010-01-01

Chlamydia trachomatis is a major cause of bacterial sexually transmitted infections worldwide. In 2006, a new variant of C. trachomatis (nvCT), carrying a 377 bp deletion within the plasmid, was reported in Sweden. This deletion included the targets used by the commercial diagnostic systems from Roche and Abbott. The nvCT is clonal (serovar/genovar E) and it spread rapidly in Sweden, undiagnosed by these systems. The degree of spread may also indicate an increased biological fitness of nvCT. The aims of this study were to describe the genome of nvCT, to compare the nvCT genome to all available C. trachomatis genome sequences and to investigate the biological properties of nvCT. An early nvCT isolate (Sweden2) was analysed by genome sequencing, growth kinetics, microscopy, cell tropism assay and antimicrobial susceptibility testing. It was compared with relevant C. trachomatis isolates, including a similar serovar E C. trachomatis wild-type strain that circulated in Sweden prior to the initially undetected expansion of nvCT. The nvCT genome does not contain any major genetic polymorphisms – the genes for central metabolism, development cycle and virulence are conserved – or phenotypic characteristics that indicate any altered biological fitness. This is supported by the observations that the nvCT and wild-type C. trachomatis infections are very similar in terms of epidemiological distribution, and that differences in clinical signs are only described, in one study, in women. In conclusion, the nvCT does not appear to have any altered biological fitness. Therefore, the rapid transmission of nvCT in Sweden was due to the strong diagnostic selective advantage and its introduction into a high-frequency transmitting population. PMID:20093289

[Diagnostic value of (18)F-FDG PET/CT for solitary nodular-type bronchoalveolar carcinoma].

PubMed

Liu, Weikun; Li, Xiangdong; Quan, Jiangtao; Ouyang, Xi; Zheng, Hui

2013-01-01

To assess the value of (18)F-FDG PET/CT in the diagnosis of solitary nodular-type bronchoalveolar carcinoma (BAC). The clinical and radiographic data were analyzed retrospectively in 30 patients with pathologically confirmed solitary nodular-type BAC who underwent (18)F-FDG PET/CT examinations between August, 2005 and December, 2006. The morphological and radioactive findings of the lesions were reviewed, and the maximum standard uptake values (SUVmax) were measured. The diagnostic accuracy of PET, PET/CT, and HRCT were analyzed. The (18)F-FDG SUV was markedly lower in BAC than in other well differentiated adenocarcinoma. In 19 of the BAC cases, PET showed a SUVmax of no less than 2.5, demonstrating positive changes. Of the total of 30 cases, 5 had ground glass opacity (GGO) changes, 3 exhibited mixed nodules with GGO changes around the lesions, and 22 cases presented with solid nodules. HRCT showed that BAC located often in the superior lobes of the bilateral lungs, mostly below the pleura in the surrounding lung field; the lesions were patchy or nodular with irregular shapes, showing lobulation in 22 cases, spiculation in 15 cases, pleural indentation in 21 cases, and vacuolar changes in 4 cases. The diagnostic accuracy of PET, PET/CT and HRCT for solitary nodular-type BAC was 36.67%, 93.33%, and 93.33%, respectively. The SUVmax of BAC provides only limited value for defining the nature of the lesions, but can serve as a general reference for assessing the disease activity. PET/CT, which allows both functional and imaging assessment, can be a valuable modality to reduce the misdiagnosis rate of BAC.

[Diagnostic value of (18)F-FDG PET/CT for solitary nodular-type bronchoalveolar carcinoma].

PubMed

Liu, Wei-Kun; Li, Xiang-Dong; Quan, Jiang-Tao; Ouyang, Xi; Zheng, Hui

2015-01-01

To assess the value of (18)F-FDG PET/CT in the diagnosis of solitary nodular-type bronchoalveolar carcinoma (BAC). The clinical and radiographic data were analyzed retrospectively in 30 patients with pathologically confirmed solitary nodular-type BAC who underwent (18)F-FDG PET/CT examinations between August, 2005 and December, 2006. The morphological and radioactive findings of the lesions were reviewed, and the maximum standard uptake values (SUVmax) were measured. The diagnostic accuracy of PET, PET/CT, and HRCT were analyzed. The (18)F-FDG SUV was markedly lower in BAC than in other well differentiated adenocarcinoma. In 19 of the BAC cases, PET showed a SUVmax of no less than 2.5, demonstrating positive changes. Of the total of 30 cases, 5 had ground glass opacity (GGO) changes, 3 exhibited mixed nodules with GGO changes around the lesions, and 22 cases presented with solid nodules. HRCT showed that BAC located often in the superior lobes of the bilateral lungs, mostly below the pleura in the surrounding lung field; the lesions were patchy or nodular with irregular shapes, showing lobulation in 22 cases, spiculation in 15 cases, pleural indentation in 21 cases, and vacuolar changes in 4 cases. The diagnostic accuracy of PET, PET/CT and HRCT for solitary nodular-type BAC was 36.67%, 93.33%, and 93.33%, respectively. The SUVmax of BAC provides only limited value for defining the nature of the lesions, but can serve as a general reference for assessing the disease activity. PET/CT, which allows both functional and imaging assessment, can be a valuable modality to reduce the misdiagnosis rate of BAC.

Time-Adjusted Internal Target Volume: A Novel Approach Focusing on Heterogeneity of Tumor Motion Based on 4-Dimensional Computed Tomography Imaging for Radiation Therapy Planning of Lung Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nishibuchi, Ikuno; Department of Radiation Oncology, Hiroshima Prefectural Hospital, Hiroshima; Kimura, Tomoki, E-mail: tkkimura@hiroshima-u.ac.jp

2014-08-01

Purpose: To consider nonuniform tumor motion within the internal target volume (ITV) by defining time-adjusted ITV (TTV), a volume designed to include heterogeneity of tumor existence on the basis of 4-dimensional computed tomography (4D-CT). Methods and Materials: We evaluated 30 lung cancer patients. Breath-hold CT (BH-CT) and free-breathing 4D-CT scans were acquired for each patient. The tumors were manually delineated using a lung CT window setting (window, 1600 HU; level, −300 HU). Tumor in BH-CT images was defined as gross tumor volume (GTV), and the sum of tumors in 4D-CT images was defined as ITV-4D. The TTV images were generatedmore » from the 4D-CT datasets, and the tumor existence probability within ITV-4D was calculated. We calculated the TTV{sub 80} value, which is the percentage of the volume with a tumor existence probability that exceeded 80% on ITV-4D. Several factors that affected the TTV{sub 80} value, such as the ITV-4D/GTV ratio or tumor centroid deviation, were evaluated. Results: Time-adjusted ITV images were acquired for all patients, and tumor respiratory motion heterogeneity was visualized. The median (range) ITV-4D/GTV ratio and median tumor centroid deviation were 1.6 (1.0-4.1) and 6.3 mm (0.1-30.3 mm), respectively. The median TTV{sub 80} value was 43.3% (2.9-98.7%). Strong correlations were observed between the TTV{sub 80} value and the ITV-4D/GTV ratio (R=−0.71) and tumor centroid deviation (R=−0.72). The TTV images revealed the tumor motion pattern features within ITV. Conclusions: The TTV images reflected nonuniform tumor motion, and they revealed the tumor motion pattern features, suggesting that the TTV concept may facilitate various aspects of radiation therapy planning of lung cancer while incorporating respiratory motion in the future.« less

Reference ranges for LVEF and LV volumes from electrocardiographically gated 82Rb cardiac PET/CT using commercially available software.

PubMed

Bravo, Paco E; Chien, David; Javadi, Mehrbod; Merrill, Jennifer; Bengel, Frank M

2010-06-01

Electrocardiographic gating is increasingly used for (82)Rb cardiac PET/CT, but reference ranges for global functional parameters are not well defined. We sought to establish reference values for left ventricular ejection fraction (LVEF), end systolic volume (ESV), and end diastolic volume (EDV) using 4 different commercial software packages. Additionally, we compared 2 different approaches for the definition of a healthy individual. Sixty-two subjects (mean age +/- SD, 49 +/- 9 y; 85% women; mean body mass index +/- SD, 34 +/- 10 kg/m(2)) who underwent (82)Rb-gated myocardial perfusion PET/CT were evaluated. All subjects had normal myocardial perfusion and no history of coronary artery disease (CAD) or cardiomyopathy. Subgroup 1 consisted of 34 individuals with low pretest probability of CAD (<10%), and subgroup 2 comprised 28 subjects who had no atherosclerosis on a coronary CT angiogram obtained concurrently during the PET/CT session. LVEF, ESV, and EDV were calculated at rest and during dipyridamole-induced stress, using CardIQ Physio (a dedicated PET software) and the 3 major SPECT software packages (Emory Cardiac Toolbox, Quantitative Gated SPECT, and 4DM-SPECT). Mean LVEF was significantly different among all 4 software packages. LVEF was most comparable between CardIQ Physio (62% +/- 6% and 54% +/- 7% at stress and rest, respectively) and 4DM-SPECT (64% +/- 7% and 56% +/- 8%, respectively), whereas Emory Cardiac Toolbox yielded higher values (71% +/- 6% and 65% +/- 6%, respectively, P < 0.001) and Quantitated Gated SPECT lower values (56% +/- 8% and 50% +/- 8%, respectively, P < 0.001). Subgroup 1 (low likelihood) demonstrated higher LVEF values than did subgroup 2 (normal CT angiography findings), using all software packages (P < 0.05). However, mean ESV and EDV at stress and rest were comparable between both subgroups (p = NS). Intra- and interobserver agreement were excellent for all methods. The reference range of LVEF and LV volumes from gated (82)Rb PET/CT varies significantly among available software programs and therefore cannot be used interchangeably. LVEF results were higher when healthy subjects were defined by a low pretest probability of CAD than by normal CT angiography results.

18-Fluorodeoxy-Glucose Positron Emission Tomography- Computed Tomography (18-FDG-PET/CT) for Gross Tumor Volume (GTV) Delineation in Gastric Cancer Radiotherapy

PubMed

Dębiec, Kinga; Wydmański, Jerzy; Gorczewska, Izabela; Leszczyńska, Paulina; Gorczewski, Kamil; Leszczyński, Wojciech; d’Amico, Andrea; Kalemba, Michał

2017-11-26

Purpose: Evaluation of the 18-fluorodeoxy-glucose positron emission tomography-computed tomography (18-FDGPET/ CT) for gross tumor volume (GTV) delineation in gastric cancer patients undergoing radiotherapy. Methods: In this study, 29 gastric cancer patients (17 unresectable and 7 inoperable) were initially enrolled for radical chemoradiotherapy (45Gy/25 fractions + chemotherapy based on 5 fluorouracil) or radiotherapy alone (45Gy/25 fractions) with planning based on the 18-FDG-PET/CT images. Five patients were excluded due to excess blood glucose levels (1), false-negative positron emission tomography (1) and distant metastases revealed by 18-FDG-PET/CT (3). The analysis involved measurement of metabolic tumor volumes (MTVs) performed on PET/CT workstations. Different threshold levels of the standardized uptake value (SUV) and liver uptake were set to obtain MTVs. Secondly, GTVPET values were derived manually using the positron emission tomography (PET) dataset blinded to the computed tomography (CT) data. Subsequently, GTVCT values were delineated using a radiotherapy planning system based on the CT scans blinded to the PET data. The referenced GTVCT values were correlated with the GTVPET and were compared with a conformality index (CI). Results: The mean CI was 0.52 (range, 0.12-0.85). In 13/24 patients (54%), the GTVPET was larger than GTVCT, and in the remainder, GTVPET was smaller. Moreover, the cranio-caudal diameter of GTVPET in 16 cases (64%) was larger than that of GTVCT, smaller in 7 cases (29%), and unchanged in one case. Manual PET delineation (GTVPET) achieved the best correlation with GTVCT (Pearson correlation = 0.76, p <0.0001). Among the analyzed MTVs, a statistically significant correlation with GTVCT was revealed for MTV10%SUVmax (r = 0.63; p = 0.0014), MTVliv (r = 0.60; p = 0.0021), MTVSUV2.5 (r = 0.54; p = 0.0063); MTV20%SUVmax (r = 0.44; p = 0.0344); MTV30%SUVmax (r = 0.44; p = 0.0373). Conclusion: 18-FDG-PET/CT in gastric cancer radiotherapy planning may affect the GTV delineation. https://www.ncbi.nlm.nih.gov/pubmed/management

Dual-energy CT for detection of contrast enhancement or leakage within high-density haematomas in patients with intracranial haemorrhage.

PubMed

Watanabe, Yoshiyuki; Tsukabe, Akio; Kunitomi, Yuki; Nishizawa, Mitsuo; Arisawa, Atsuko; Tanaka, Hisashi; Yoshiya, Kazuhisa; Shimazu, Takeshi; Tomiyama, Noriyuki

2014-04-01

Our study aimed to elucidate the diagnostic performance of dual-energy CT (DECT) in the detection of contrast enhancement in intracranial haematomas (ICrH) with early phase dual-energy computed tomography angiography (CTA) and compare the results with those obtained by delayed CT enhancement. Thirty-six patients with ICrH were retrospectively included in this study. All patients had undergone single-energy non-contrast CT and contrast-enhanced dual-source DECT. DECT images were post-processed with commercial software, followed by obtaining iodine images and virtual non-contrast images and generating combined images that created the impression of 120-kVp images. Two neuroradiologists, blinded to the patients' data, reviewed two reading sessions: session A (non-contrast CT and combined CT) and session B (non-contrast CT, combined CT, and iodine images) for detection of contrast enhancement in the haematomas. Contrast leakage or enhancement was detected in 23 (57.5 %) out of 40 haemorrhagic lesions in 36 patients on delayed CT. Three enhanced lesions were depicted only in the DECT iodine images. The sensitivity, specificity, positive predictive value, and negative predictive value of session A were 82.6, 94.1, 95.0, and 80.0 %, respectively, and those of session B were 95.7, 94.1, 95.7, and 94.1 %, respectively. DECT emphasised the iodine enhancement and facilitated the detection of contrast enhancement or leakage.

Analysis of pulmonary pure ground-glass nodule in enhanced dual energy CT imaging for predicting invasive adenocarcinoma: comparing with conventional thin-section CT imaging

PubMed Central

Zhang, Ying; Tang, Jian; Xu, Jianrong

2017-01-01

Background To investigate the value of dual energy computed tomography (DECT) parameters (including iodine concentration and monochromatic CT numbers) for predicting pure ground-glass nodules (pGGNs) of invasive adenocarcinoma (IA). Methods A total of 55 resected pGGNs evaluated with both unenhanced thin-section CT (TSCT) and enhanced DECT scans were included. Correlations between histopathology [adenocarcinoma in situ (AIS), minimally IA (MIA), and IA] and CT scan characteristics were examined. CT scan and clinicodemographic data were investigated by univariate and multivariate analysis to identify features that helped distinguish IA from AIS or MIA. Results Both normalized iodine concentration (NIC) of IA and slope of spectral curve [slope(k)] were not significantly different between IA and AIS or MIA. Size, performance of pleural retraction and enhanced monochromatic CT attenuation values of 120–140 keV were significantly higher for IA. In multivariate regression analysis, size and enhanced monochromatic CT number of 140 keV were independent predictors for IA. Using the two parameters together, the diagnostic capacity of IA could be improved from 0.697 or 0.635 to 0.713. Conclusions DECT could help demonstrate blood supply and indicate invasion extent of pGGNs, and monochromatic CT number of higher energy (especially 140 keV) would be better for diagnosing IA than lower energies. Together with size of pGGNs, the diagnostic capacity of IA could be better. PMID:29312701

Scanning and War: Utility of FAST and CT in the Assessment of Battlefield Abdominal Trauma.

PubMed

Smith, Iain M; Naumann, David N; Marsden, Max E R; Ballard, Mark; Bowley, Douglas M

2015-08-01

To determine utilization and accuracy of focused assessment with sonography for trauma (FAST) and computed tomography (CT) in a mature military trauma system to inform service provision for future conflicts. FAST and CT scans undertaken by attending radiologists contribute to surgical decision making for battlefield casualties at the Joint Force, Role 3 Medical Treatment Facility at Camp Bastion (R3), Afghanistan. Registry data for abdominally injured casualties treated at R3 from July to November 2012 were matched to radiological and surgical records to determine diagnostic accuracy for FAST and CT and their influence on casualty management. A total of 468 casualties met inclusion criteria, of whom 85.0% underwent FAST and 86.1% abdominal CT; 159 (34.0%) had abdominal injuries. For detection of intra-abdominal injury, FAST sensitivity (Sn) was 0.56, specificity (Sp) 0.98, positive predictive value (PPV) 0.87, negative predictive value (NPV) 0.90, and accuracy (Acc) 0.89. For CT, Sn was 0.99, Sp 0.99, PPV 0.96, NPV 1.00, and Acc 0.99. Forty-six solid organ injuries were identified in 38 patients by CT; 17 were managed nonoperatively. A further 61 patients avoided laparotomy after CT confirmed extra-abdominal wounds only. The negative laparotomy rate was 3.9%. FAST and CT contribute to triage, guide surgical management, and reduce nontherapeutic laparotomy. When imaging is available, these data challenge current doctrine about inadvisability of nonoperative management of abdominal injury after combat trauma.

Trapping volumetric measurement by multidetector CT in chronic obstructive pulmonary disease: Effect of CT threshold

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xiaohua; Yuan, Huishu; Duan, Jianghui

2013-08-15

Purpose: The purpose of this study was to evaluate the effect of various computed tomography (CT) thresholds on trapping volumetric measurements by multidetector CT in chronic obstructive pulmonary disease (COPD).Methods: Twenty-three COPD patients were scanned with a 64-slice CT scanner in both the inspiratory and expiratory phase. CT thresholds of −950 Hu in inspiration and −950 to −890 Hu in expiration were used, after which trapping volumetric measurements were made using computer software. Trapping volume percentage (Vtrap%) under the different CT thresholds in the expiratory phase and below −950 Hu in the inspiratory phase was compared and correlated with lungmore » function.Results: Mean Vtrap% was similar under −930 Hu in the expiratory phase and below −950 Hu in the inspiratory phase, being 13.18 ± 9.66 and 13.95 ± 6.72 (both lungs), respectively; this difference was not significant (P= 0.240). Vtrap% under −950 Hu in the inspiratory phase and below the −950 to −890 Hu threshold in the expiratory phase was moderately negatively correlated with the ratio of forced expiratory volume in one second to forced vital capacity and the measured value of forced expiratory volume in one second as a percentage of the predicted value.Conclusions: Trapping volumetric measurement with multidetector CT is a promising method for the quantification of COPD. It is important to know the effect of various CT thresholds on trapping volumetric measurements.« less

Anastomotic leakage after colorectal surgery: diagnostic accuracy of CT.

PubMed

Kauv, Paul; Benadjaoud, Samir; Curis, Emmanuel; Boulay-Coletta, Isabelle; Loriau, Jerome; Zins, Marc

2015-12-01

To evaluate the diagnostic accuracy of CT in postoperative colorectal anastomotic leakage (AL). Two independent blinded radiologists reviewed 153 CTs performed for suspected AL within 60 days after surgery in 131 consecutive patients, with (n = 58) or without (n = 95) retrograde contrast enema (RCE). Results were compared to original interpretations. The reference standard was reoperation or consensus (a radiologist and a surgeon) regarding clinical, laboratory, radiological, and follow-up data after medical treatment. AL was confirmed in 34/131 patients. For the two reviewers and original interpretation, sensitivity of CT was 82 %, 87 %, and 71 %, respectively; specificity was 84 %, 84 %, and 92 %. RCE significantly increased the positive predictive value (from 40 % to 88 %, P = 0.0009; 41 % to 92 %, P = 0.0016; and 40 % to 100 %, P = 0.0006). Contrast extravasation was the most sensitive (reviewers, 83 % and 83 %) and specific (97 % and 97 %) sign and was significantly associated with AL by univariate analysis (P < 0.0001 and P < 0.0001). By multivariate analysis with recursive partitioning, CT with RCE was accurate to confirm or rule out AL with contrast extravasation. CT with RCE is accurate for diagnosing postoperative colorectal AL. Contrast extravasation is the most reliable sign. RCE should be performed during CT for suspected AL. • CT accurately diagnosed clinically suspected colorectal AL and showed good interobserver agreement • Contrast extravasation was the most sensitive and specific CT sign • Retrograde contrast enema during CT improved positive predictive value • Retrograde contrast enema decreased false-negative or indeterminate original CT interpretations.

Adrenal venous sampling for stratifying patients for surgery of adrenal nodules detected using dynamic contrast enhanced CT

PubMed Central

Kim, Jin Young; Kim, See Hyung; Lee, Hee Jung; Kim, Young Hwan; Kim, Mi Jeong; Cho, Seung Hyun

2014-01-01

PURPOSE We aimed to assess the value of adrenal venous sampling (AVS) for diagnosing primary aldosteronism (PA) subtypes in patients with a unilateral nodule detected on adrenal computed tomography (CT) and scheduled for adrenalectomy. MATERIALS AND METHODS This retrospective study included 80 consecutive patients with PA undergoing CT and AVS. Different lateralization indices were assessed, and a cutoff established using receiver operating characteristic curve analysis. The value of CT alone versus CT with AVS for differentiating PA subtypes was compared. The adrenalectomy outcome was assessed, and predictors of cure were determined using univariate analysis. RESULTS AVS was successful in 68 patients. A cortisol-corrected aldosterone affected-to-unaffected ratio cutoff of 2.0 and affected-to-inferior vena cava ratio cutoff of 1.4 were the best lateralization indices, with accuracies of 82.5% and 80.4%, respectively. CT and AVS diagnosed 38 patients with aldosterone-producing adenomas, five patients with unilateral adrenal hyperplasia, and 25 patients with bilateral adrenal hyperplasia. Of the 52 patients with a nodule detected on CT, subsequent AVS diagnosed bilateral adrenal hyperplasia in 14 patients (27%). Compared to the results of combining CT with AVS, the accuracy of CT alone for diagnosing aldosterone-producing adenomas was 71.1% (P < 0.001). The cure rate for hypertension after adrenalectomy was 39.2%, with improvement in 53.5% of patients. On univariate analysis, predictors of persistent hypertension were male gender and preoperative systolic blood pressure. CONCLUSION To avoid inappropriate surgery, AVS is necessary for diagnosing unilateral nodules with aldosterone hypersecretion detected by CT. PMID:24047720

Diagnostic role of (99)Tc(m)-MDP SPECT/CT combined SPECT/MRI Multi modality imaging for early and atypical bone metastases.

PubMed

Chen, Xiao-Liang; Li, Qian; Cao, Lin; Jiang, Shi-Xi

2014-01-01

The bone metastasis appeared early before the bone imaging for most of the above patients. (99)Tc(m)-MDP ((99)Tc(m) marked methylene diphosphonate) bone imaging could diagnosis the bone metastasis with highly sensitivity, but with lower specificity. The aim of this study is to explore the diagnostic value of (99)Tc(m)-MDP SPECT/CT combined SPECT/MRI Multi modality imaging for the early period atypical bone metastases. 15 to 30 mCi (99)Tc(m)-MDP was intravenously injected to the 34 malignant patients diagnosed as doubtful early bone metastases. SPECT, CT and SPECT/CT images were captured and analyzed consequently. For the patients diagnosed as early period atypical bone metastases by SPECT/CT, combining the SPECT/CT and MRI together as the SPECT/MRI integrated image. The obtained SPECT/MRI image was analyzed and compared with the pathogenic results of patients. The results indicated that 34 early period doubtful metastatic focus, including 34 SPECT positive focus, 17 focus without special changes by using CT method, 11 bone metastases focus by using SPECT/CT method, 23 doubtful bone metastases focus, 8 doubtful bone metastases focus, 14 doubtful bone metastases focus and 2 focus without clear image. Totally, SPECT/CT combined with SPECT/MRI method diagnosed 30 bone metastatic focus and 4 doubtfully metastatic focus. In conclusion, (99)Tc(m)-MDP SPECT/CT combined SPECT/MRI Multi modality imaging shows a higher diagnostic value for the early period bone metastases, which also enhances the diagnostic accuracy rate.

Diagnostic utility of attenuation measurement (Hounsfield units) in computed tomography stonogram in predicting the radio-opacity of urinary calculi in plain abdominal radiographs.

PubMed

Chua, Michael E; Gatchalian, Glenn T; Corsino, Michael Vincent; Reyes, Buenaventura B

2012-10-01

(1) To determine the best cut-off level of Hounsfield units (HU) in the CT stonogram that would predict the appearance of a urinary calculi in plain KUB X-ray; (2) to estimate the sensitivity and specificity of the best cut-off HU; and (3) to determine whether stone size and location affect the in vivo predictability. A prospective cross-sectional study of patients aged 18-85 diagnosed with urolithiases on CT stonogram with concurrent plain KUB radiograph was conducted. Appearance of stones was recorded, and significant difference between radiolucent and radio-opaque CT attenuation level was determined using ANOVA. Receiver operating characteristics (ROC) curve determined the best HU cut-off value. Stone size and location were used for factor variability analysis. A total of 184 cases were included in this study, and the average urolithiasis size on CT stonogram was 0.84 cm (0.3-4.9 cm). On KUB X-ray, 34.2 % of the urolithiases were radiolucent and 65.8 % were radio-opaque. Mean value of CT Hounsfield unit for radiolucent stones was 358.25 (±156), and that for radio-opaque stones was 816.51 (±274). ROC curve determined the best cut-off value of HU at 498.5, with the sensitivity of 89.3 % and specificity of 87.3 %. For >4 mm stones, the sensitivity was 91.3 % and the specificity was 81.8 %. On the other hand, for =<4 mm stones, the sensitivity was 60 % and the specificity was 89.5 %. Based on the constructed ROC curve, a threshold value of 498.5 HU in CT stonogram was established as cut-off in determining whether a calculus is radio-opaque or radiolucent. The determined overall sensitivity and specificity of the set cut-off HU value are optimal. Stone size but not location affects the sensitivity and specificity.

The Anatomical Biological Value on Pretreatment (18)F-fluorodeoxyglucose Positron Emission Tomography Computed Tomography Predicts Response and Survival in Locally Advanced Head and Neck Cancer.

PubMed

Ashamalla, Hani; Mattes, Malcolm; Guirguis, Adel; Zaidi, Arifa; Mokhtar, Bahaa; Tejwani, Ajay

2014-05-01

(18)F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) has become increasingly relevant in the staging of head and neck cancers, but its prognostic value is controversial. The objective of this study was to evaluate different PET/CT parameters for their ability to predict response to therapy and survival in patients treated for head and neck cancer. A total of 28 consecutive patients with a variety of newly diagnosed head and neck cancers underwent PET/CT scanning at our institution before initiating definitive radiation therapy. All underwent a posttreatment PET/CT to gauge tumor response. Pretreatment PET/CT parameters calculated include the standardized uptake value (SUV) and the anatomical biological value (ABV), which is the product of SUV and greatest tumor diameter. Maximum and mean values were studied for both SUV and ABV, and correlated with response rate and survival. The mean pretreatment tumor ABVmax decreased from 35.5 to 7.9 (P = 0.0001). Of the parameters tested, only pretreatment ABVmax was significantly different among those patients with a complete response (CR) and incomplete response (22.8 vs. 65, respectively, P = 0.021). This difference was maximized at a cut-off ABVmax of 30 and those patients with ABVmax < 30 were significantly more likely to have a CR compared to those with ABVmax of ≥ 30 (93.8% vs. 50%, respectively, P = 0.023). The 5-year overall survival was 80% compared to 36%, respectively, (P = 0.028). Multivariate analysis confirmed that ABVmax was an independent prognostic factor. Our data supports the use of PET/CT, and specifically ABVmax, as a prognostic factor in head and neck cancer. Patients who have an ABVmax ≥ 30 were more likely to have a poor outcome with chemoradiation alone, and a more aggressive trimodality approach may be indicated in these patients.

Predictive and prognostic value of PET/CT imaging post-chemoradiotherapy and clinical decision-making consequences in locally advanced head & neck squamous cell carcinoma: a retrospective study.

PubMed

Kim, Ryul; Ock, Chan-Young; Keam, Bhumsuk; Kim, Tae Min; Kim, Jin Ho; Paeng, Jin Chul; Kwon, Seong Keun; Hah, J Hun; Kwon, Tack-Kyun; Kim, Dong-Wan; Wu, Hong-Gyun; Sung, Myung-Whun; Heo, Dae Seog

2016-02-17

The accuracy of (18)F-fluorodeoxygluocose positron emission tomography/computed tomography (PET/CT) in predicting immediate failure after radical chemoradiotherapy (CRT) for HNSCC is poorly characterized at present. The purpose of this study was to examine PET/CT as a predictive and prognostic gauge of immediate failure after CRT and determine the impact of these studies on clinical decision making in terms of salvage surgery. Medical records of 78 consecutive patients receiving radical CRT for locally advanced HNSCC were reviewed, analyzing PET/CTs done before and 3 months after CRT. Immediate failure was defined as residual disease or locoregional and/or systemic relapse within 6 months after CRT. Maximum standard uptake value (SUV) of post CRT PET/CT (postSUVmax) was found optimal for predicting immediate failure at a cutpoint of 4.4. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were 90.0%, 83.8%, 98.3%, and 45.0%, respectively. Of 78 patients studied, postSUVmax ≥ 4.4 prevailed in 20 (25.6%), with postSUVmax <4.4 in 58 (74.4%). At postSUVmax ≥ 4.4 (vs. postSUVmax <4.4) OS was poorer by comparison (3-year OS: 56.9 vs. 87.7%; P = 0.005), as was progression-free survival (3-year PFS: 42.9 vs. 81.1%; P < 0.001). At postSUVmax ≥ 4.4, OS with and without immediate salvage surgery did not differ significantly (3-year OS: 60.0 vs. 55.6%; Log-rank P = 0.913). Post CRT PET/CT imaging has prognostic value in terms of OS and PFS and is useful in predicting immediate therapeutic failure, given its high NPV. However, OS was not significantly altered by early salvage surgery done on the basis of post CRT PET/CT findings.

Functional Gene Differences in Soil Microbial Communities from Conventional, Low-Input, and Organic Farmlands

PubMed Central

Xue, Kai; Wu, Liyou; Deng, Ye; He, Zhili; Van Nostrand, Joy; Robertson, Philip G.; Schmidt, Thomas M.

2013-01-01

Various agriculture management practices may have distinct influences on soil microbial communities and their ecological functions. In this study, we utilized GeoChip, a high-throughput microarray-based technique containing approximately 28,000 probes for genes involved in nitrogen (N)/carbon (C)/sulfur (S)/phosphorus (P) cycles and other processes, to evaluate the potential functions of soil microbial communities under conventional (CT), low-input (LI), and organic (ORG) management systems at an agricultural research site in Michigan. Compared to CT, a high diversity of functional genes was observed in LI. The functional gene diversity in ORG did not differ significantly from that of either CT or LI. Abundances of genes encoding enzymes involved in C/N/P/S cycles were generally lower in CT than in LI or ORG, with the exceptions of genes in pathways for lignin degradation, methane generation/oxidation, and assimilatory N reduction, which all remained unchanged. Canonical correlation analysis showed that selected soil (bulk density, pH, cation exchange capacity, total C, C/N ratio, NO3−, NH4+, available phosphorus content, and available potassium content) and crop (seed and whole biomass) variables could explain 69.5% of the variation of soil microbial community composition. Also, significant correlations were observed between NO3− concentration and denitrification genes, NH4+ concentration and ammonification genes, and N2O flux and denitrification genes, indicating a close linkage between soil N availability or process and associated functional genes. PMID:23241975

Cardiac imaging with multi-sector data acquisition in volumetric CT: variation of effective temporal resolution and its potential clinical consequences

NASA Astrophysics Data System (ADS)

Tang, Xiangyang; Hsieh, Jiang; Taha, Basel H.; Vass, Melissa L.; Seamans, John L.; Okerlund, Darin R.

2009-02-01

With increasing longitudinal detector dimension available in diagnostic volumetric CT, step-and-shoot scan is becoming popular for cardiac imaging. In comparison to helical scan, step-and-shoot scan decouples patient table movement from cardiac gating/triggering, which facilitates the cardiac imaging via multi-sector data acquisition, as well as the administration of inter-cycle heart beat variation (arrhythmia) and radiation dose efficiency. Ideally, a multi-sector data acquisition can improve temporal resolution at a factor the same as the number of sectors (best scenario). In reality, however, the effective temporal resolution is jointly determined by gantry rotation speed and patient heart beat rate, which may significantly lower than the ideal or no improvement (worst scenario). Hence, it is clinically relevant to investigate the behavior of effective temporal resolution in cardiac imaging with multi-sector data acquisition. In this study, a 5-second cine scan of a porcine heart, which cascades 6 porcine cardiac cycles, is acquired. In addition to theoretical analysis and motion phantom study, the clinical consequences due to the effective temporal resolution variation are evaluated qualitative or quantitatively. By employing a 2-sector image reconstruction strategy, a total of 15 (the permutation of P(6, 2)) cases between the best and worst scenarios are studied, providing informative guidance for the design and optimization of CT cardiac imaging in volumetric CT with multi-sector data acquisition.

Residual neck disease management in squamous-cell carcinoma of the head and neck treated with radiotherapy plus cetuximab.

PubMed

Montal, R; Oliva, M; Taberna, M; De Avila, L; Rovira, A; Cos, M; Mañós, M; Navarro, V; Nogués, J; Lozano, A; Rodríguez, L; Vilajosana, E; Vázquez, S; Mesia, R

2016-11-01

Management of residual neck disease (RND) is one of the unsolved points after bio-radiotherapy (BRT) in loco-regional advanced squamous-cell carcinoma of the head and neck (SCCHN). The aims of the study were to characterize the radiological pattern of response by computed tomography (CT) and to assess the role of positron-emission tomography (PET)/CT in this setting for a better decision-making in the indication of neck dissection (ND). We retrospectively reviewed 202 patients consecutively diagnosed with node-positive SCCHN (N1: 24; N2: 152; N3: 26) who had been treated with concomitant radiotherapy and cetuximab with or without previous induction chemotherapy between 2006 and 2013. Radiological evaluation after treatment was assessed by standard criteria using CT and in addition by PET/CT when RND was suspected in cases from 2010. There were 42 (21 %) patients who achieved complete response of the primary tumor persisting RND by CT. From this group, 24 patients were managed without PET/CT, leading to the performance of ND in 22 (92 %). On the other hand, 18 patients underwent PET/CT and ND was performed in only 6 (33 %). The overall survival was not different between both groups (p = 0.32). After histological examination and follow-up, PET/CT obtained a positive predictive value of 56 % and a negative predictive value of 89 %. Radiological response after BRT is similar to that after treatment with chemo-radiotherapy, thereby validating in this scenario the accepted CT criteria to define complete response of the neck. However, when RND is suspected by CT, PET/CT is useful to prevent unnecessary ND.

Evaluation of treatment response after chemoembolisation (TACE) in hepatocellular carcinoma using real time image fusion of contrast-enhanced ultrasound (CEUS) and computed tomography (CT)--preliminary results.

PubMed

Wobser, Hella; Wiest, Reiner; Salzberger, Bernd; Wohlgemuth, Walter Alexander; Stroszczynski, Christian; Jung, Ernst-Michael

2014-01-01

To evaluate treatment response of hepatocellular carcinoma (HCC) after transarterial chemoembolization (TACE) with a new real-time imaging fusion technique of contrast-enhanced ultrasound (CEUS) with multi-slice detection computed tomography (CT) in comparison to conventional post-interventional follow-up. 40 patients with HCC (26 male, ages 46-81 years) were evaluated 24 hours after TACE using CEUS with ultrasound volume navigation and image fusion with CT compared to non-enhanced CT and follow-up contrast-enhanced CT after 6-8 weeks. Reduction of tumor vascularization to less than 25% was regarded as "successful" treatment, whereas reduction to levels >25% was considered as "partial" treatment response. Homogenous lipiodol retention was regarded as successful treatment in non-enhanced CT. Post-interventional image fusion of CEUS with CT was feasible in all 40 patients. In 24 patients (24/40), post-interventional image fusion with CEUS revealed residual tumor vascularity, that was confirmed by contrast-enhanced CT 6-8 weeks later in 24/24 patients. In 16 patients (16/40), post-interventional image fusion with CEUS demonstrated successful treatment, but follow-up CT detected residual viable tumor (6/16). Non-enhanced CT did not identify any case of treatment failure. Image fusion with CEUS assessed treatment efficacy with a specificity of 100%, sensitivity of 80% and a positive predictive value of 1 (negative predictive value 0.63). Image fusion of CEUS with CT allows a reliable, highly specific post-interventional evaluation of embolization response with good sensitivity without any further radiation exposure. It can detect residual viable tumor at early state, resulting in a close patient monitoring or re-therapy.

The Value of 18F-FDG PET/CT in Diagnosis and During Follow-up in 273 Patients with Chronic Q Fever.

PubMed

Kouijzer, Ilse J E; Kampschreur, Linda M; Wever, Peter C; Hoekstra, Corneline; van Kasteren, Marjo E E; de Jager-Leclercq, Monique G L; Nabuurs-Franssen, Marrigje H; Wegdam-Blans, Marjolijn C A; Ammerlaan, Heidi S M; Buijs, Jacqueline; Geus-Oei, Lioe-Fee de; Oyen, Wim J G; Bleeker-Rovers, Chantal P

2018-01-01

In 1%-5% of all acute Q fever infections, chronic Q fever develops, mostly manifesting as endocarditis, infected aneurysms, or infected vascular prostheses. In this study, we investigated the diagnostic value of 18 F-FDG PET/CT in chronic Q fever at diagnosis and during follow-up. Methods: All adult Dutch patients suspected of chronic Q fever who were diagnosed since 2007 were retrospectively included until March 2015, when at least one 18 F-FDG PET/CT scan was obtained. Clinical data and results from 18 F-FDG PET/CT at diagnosis and during follow-up were collected. 18 F-FDG PET/CT scans were prospectively reevaluated by 3 nuclear medicine physicians using a structured scoring system. Results: In total, 273 patients with possible, probable, or proven chronic Q fever were included. Of all 18 F-FDG PET/CT scans performed at diagnosis, 13.5% led to a change in diagnosis. Q fever-related mortality rate in patients with and without vascular infection based on 18 F-FDG PET/CT was 23.8% and 2.1%, respectively ( P = 0.001). When 18 F-FDG PET/CT was added as a major criterion to the modified Duke criteria, 17 patients (1.9-fold increase) had definite endocarditis. At diagnosis, 19.6% of 18 F-FDG PET/CT scans led to treatment modification. During follow-up, 57.3% of 18 F-FDG PET/CT scans resulted in treatment modification. Conclusion: 18 F-FDG PET/CT is a valuable technique in diagnosis of chronic Q fever and during follow-up, often leading to a change in diagnosis or treatment modification and providing important prognostic information on patient survival. © 2018 by the Society of Nuclear Medicine and Molecular Imaging.

Feasibility assessment of yttrium-90 liver radioembolization imaging using amplitude-based gated PET/CT

PubMed Central

Acuff, Shelley N.; Neveu, Melissa L.; Syed, Mumtaz; Kaman, Austin D.; Fu, Yitong

2018-01-01

Purpose The usage of PET/computed tomography (CT) to monitor hepatocellular carcinoma patients following yttrium-90 (90Y) radioembolization has increased. Respiratory motion causes liver movement, which can be corrected using gating techniques at the expense of added noise. This work examines the use of amplitude-based gating on 90Y-PET/CT and its potential impact on diagnostic integrity. Patients and methods Patients were imaged using PET/CT following 90Y radioembolization. A respiratory band was used to collect respiratory cycle data. Patient data were processed as both standard and motion-corrected images. Regions of interest were drawn and compared using three methods. Activity concentrations were calculated and converted into dose estimates using previously determined and published scaling factors. Diagnostic assessments were performed using a binary scale created from published 90Y-PET/CT image interpretation guidelines. Results Estimates of radiation dose were increased (P<0.05) when using amplitude-gating methods with 90Y PET/CT imaging. Motion-corrected images show increased noise, but the diagnostic determination of success, using the Kao criteria, did not change between static and motion-corrected data. Conclusion Amplitude-gated PET/CT following 90Y radioembolization is feasible and may improve 90Y dose estimates while maintaining diagnostic assessment integrity. PMID:29351124

Pancreatic fine needle aspiration. A comparison of computed tomographic and endoscopic ultrasonographic guidance.

PubMed

Qian, Xiaohua; Hecht, Jonathan L

2003-01-01

To compare the sensitivity and specificity of pancreatic fine needle aspiration (FNA) with computed tomography (CT) and endoscopic ultrasound (EUS) guidance. A 6-year retrospective review included 137 pancreatic FNAs (CT 51, magnetic resonance imaging 2 or EUS 84). Clinical or histologic follow-up was available for 110 patients. Positive (POS), suspicious (SUS), atypical, negative and unsatisfactory (UNSAT) results represented 25.5%, 7.3%, 7.3%, 40.1% and 19.1% of reported diagnoses, respectively. In detecting malignancy, the sensitivities of POS/SUS results were 71% and 42% for CT and EUS, respectively, with negative predictive value (NPV) of 41% and 45%. Also, 35% of UNSAT results were found to have malignancy. However, EUS was used on more difficult lesions, including 82% of small, cystic ones and 75% of small, solid ones. Although the apparent performance of percutaneous CT-guided biopsies surpasses that of EUS, this is due to the choice of endoscopy for more difficult lesions. The specificity and negative predictive value of EUS and CT are similar.

The CT (Hounsfield unit) number of brain tissue in healthy infants. A new reliable method for detection of possible degenerative disease.

PubMed

Boris, P; Bundgaard, F; Olsen, A

1987-01-01

It is difficult to correlate CT Hounsfield unit (H. U.) numbers from one CT investigation to another and from one CT scanner to another, especially when dealing with small changes in the brain substance, as in degenerative brain diseases in children. By subtracting the mean value of cerebrospinal fluid (CSF) from the mean value of grey and white matter, it is possible to remove most of the errors due, for example, to maladjustments, short and long-term drift, X-ray fan, and detector asymmetry. Measurements of white and grey matter using these methods showed CT H. U. numbers changing from 15 H. U. to 22 H. U. in white matter and 23 H. U. to 30 H. U. in grey matter in 86 healthy infants aged 0-5 years. In all measurements, the difference between grey and white matter was exactly 8 H. U. The method has proven to be highly accurate and reproducible.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, G; Liu, C; Liu, C

Purpose: To analyze the error in contouring the brainstem for patients with head and neck cancer who underwent radiotherapy based on computed tomography (CT) and magnetic resonance (MR) images. Methods: 20 brain tumor and 17 nasopharyngeal cancer patients were randomly selected. Each patient underwent MR and CT scanning. For each patient, one observer contoured the brainstem on CT and MR images for 10 times, and 10 observers from five centers delineated the brainstem on CT and MR images only one time. The inter- and intra-observers volume and outline variations were compared. Results: The volumes of brainstem contoured by inter- andmore » intra-observers on CT and MR images were similar (p>0.05). The reproducibility of contouring brainstem on MR images was better than that on CT images (p<0.05) for both inter- and intra-observer variability. The inter- and intra-observer for contouring on CT images reached mean values of 0.81±0.05 (p>0.05) and of 0.85±0.05 (p>0.05), respectively, while on MR images these respective values were 0.90±0.05 (p>0.05) and 0.92±0.04 (p>0.05). Conclusion: Contouring the brainstem on MR images was more accurate and reproducible than that on CT images. Precise information might be more helpful for protecting the brainstem radiation injury the patients whose lesion were closed to brainstem.« less

Evaluation of the sensitivity of scout radiographs on unenhanced helical CT in identifying ureteric calculi: a large UK tertiary referral centre experience

PubMed Central

Yap, W W; Belfield, J C; Bhatnagar, P; Kennish, S; Wah, T M

2012-01-01

Objective Unenhanced helical CT for kidney, ureter and bladder (CT KUB) has become the standard investigation for renal colic. This study aims to determine the sensitivity of scout radiographs in detecting ureteric calculi using CT KUB as a standard reference. Methods A retrospective review of consecutive patients who presented with acute flank pain and were investigated using CT KUB. 201 patients with positive ureteric calculi were included. Two radiologists independently reviewed the scout radiographs with access to CT KUB images. Each observer recorded the presence or absence of calculi, location, size and mean Hounsfield units of each calculus. Results 203 ureteric calculi were analysed from 201 patients. The overall sensitivity of scout radiographs for Observer A was 42.3% and for Observer B 52.2%, with an interobserver reliability κ-value of 0.78. The significance of mean Hounsfield units and size between two groups of patients with visible stones and those not visible were tested; the p-value for both variables was <0.0001, which is statistically significant. The study found that calculi in the upper ureter and larger than 4 mm are more likely to be seen on the scout radiograph. Conclusions Usage of CT scout radiography should be encouraged and reported routinely in conjunction with CT KUB as a baseline for treatment follow-up. PMID:22665926

Diagnostic accuracy of CT in assessing extra-regional lymphadenopathy in pancreatic and peri-ampullary cancer: a systematic review and meta-analysis.

PubMed

Tseng, Dorine S J; van Santvoort, Hjalmar C; Fegrachi, Samira; Besselink, Marc G; Zuithoff, Nicolaas P A; Borel Rinkes, Inne H; van Leeuwen, Maarten S; Molenaar, I Quintus

2014-12-01

Computed tomography (CT) is the most widely used method to assess resectability of pancreatic and peri-ampullary cancer. One of the contra-indications for curative resection is the presence of extra-regional lymph node metastases. This meta-analysis investigates the accuracy of CT in assessing extra-regional lymph node metastases in pancreatic and peri-ampullary cancer. We systematically reviewed the literature according to the PRISMA guidelines. Studies reporting on CT assessment of extra-regional lymph nodes in patients undergoing pancreatoduodenectomy were included. Data on baseline characteristics, CT-investigations and histopathological outcomes were extracted. Diagnostic accuracy, positive predictive value (PPV), negative predictive value (NPV), sensitivity and specificity were calculated for individual studies and pooled data. After screening, 4 cohort studies reporting on CT-findings and histopathological outcome in 157 patients with pancreatic or peri-ampullary cancer were included. Overall, diagnostic accuracy, specificity and NPV varied from 63 to 81, 80-100% and 67-90% respectively. However, PPV and sensitivity ranged from 0 to 100% and 0-38%. Pooled sensitivity, specificity, PPV and NPV were 25%, 86%, 28% and 84% respectively. CT has a low diagnostic accuracy in assessing extra-regional lymph node metastases in pancreatic and peri-ampullary cancer. Therefore, suspicion of extra-regional lymph node metastases on CT alone should not be considered a contra-indication for exploration. Copyright © 2014 Elsevier Ltd. All rights reserved.

Interactive machine learning for postprocessing CT images of hardwood logs

Treesearch

Erol Sarigul; A. Lynn Abbott; Daniel L. Schmoldt

2003-01-01

This paper concerns the nondestructive evaluation of hardwood logs through the analysis of computed tomography (CT) images. Several studies have shown that the commercial value of resulting boards can be increased substantially if log sawing strategies are chosen using prior knowledge of internal log defects. Although CT imaging offers a potential means of obtaining...

PSA-stratified detection rates for [68Ga]THP-PSMA, a novel probe for rapid kit-based 68Ga-labeling and PET imaging, in patients with biochemical recurrence after primary therapy for prostate cancer.

PubMed

Derlin, Thorsten; Schmuck, Sebastian; Juhl, Cathleen; Zörgiebel, Johanna; Schneefeld, Sophie M; Walte, Almut C A; Hueper, Katja; von Klot, Christoph A; Henkenberens, Christoph; Christiansen, Hans; Thackeray, James T; Ross, Tobias L; Bengel, Frank M

2018-06-01

[ 68 Ga]Tris(hydroxypyridinone)(THP)-PSMA is a novel radiopharmaceutical for one-step kit-based radiolabelling, based on direct chelation of 68 Ga 3+ at low concentration, room temperature and over a wide pH range, using direct elution from a 68 Ge/ 68 Ga-generator. We evaluated the clinical detection rates of [ 68 Ga]THP-PSMA PET/CT in patients with biochemically recurrent prostate cancer after prostatectomy. Consecutive patients (n=99) referred for evaluation of biochemical relapse of prostate cancer by [ 68 Ga]THP-PSMA PET/CT were analyzed retrospectively. Patients underwent a standard whole-body PET/CT (1 h p.i.), followed by delayed (3 h p.i.) imaging of the abdomen. PSA-stratified cohorts of positive PET/CT results, standardized uptake values (SUVs) and target-to-background ratios (TBRs) were analyzed, and compared between standard and delayed imaging. At least one lesion suggestive of recurrent or metastatic prostate cancer was identified on PET images in 52 patients (52.5%). Detection rates of [ 68 Ga]THP-PSMA PET/CT increased with increasing PSA level: 94.1% for a PSA value of ≥10 ng/mL, 77.3% for a PSA value of 2 to <10 ng/mL, 54.5% for a PSA value of 1 to <2 ng/mL, 14.3% for a PSA value of 0.5 to <1 ng/mL, 20.0% for a PSA value of >0.2 to <0.5, and 22.2% for a PSA value of 0.01 to 0.2 ng/mL. [ 68 Ga]THP-PSMA uptake (SUVs) in metastases decreased over time, whereas TBRs improved. Delayed imaging at 3 h p.i. exclusively identified pathologic findings in 2% of [ 68 Ga]THP-PSMA PET/CT scans. Detection rate was higher in patients with a Gleason score ≥8 (P=0.02) and in patients receiving androgen deprivation therapy (P=0.003). In this study, [ 68 Ga]THP-PSMA PET/CT showed suitable detection rates in patients with biochemical recurrence of prostate cancer and PSA levels ≥ 2 ng /mL. Detections rates were lower than in previous studies evaluating other PSMA ligands, though prospective direct radiotracer comparison studies are mandatory particularly in patients with low PSA levels to evaluate the relative performance of different PSMA ligands.

Iodine concentration calculated by dual-energy computed tomography (DECT) as a functional parameter to evaluate thyroid metabolism in patients with hyperthyroidism.

PubMed

Binh, Duong Duc; Nakajima, Takahito; Otake, Hidenori; Higuchi, Tetsuya; Tsushima, Yoshito

2017-07-19

Thyroid function in patients with Grave's disease is usually evaluated by thyroid scintigraphy with radioactive iodine. Recently, dual-energy computed tomography (DECT) with two different energy X-rays can calculate iodine concentrations and can be applied for iodine measurements in thyroid glands. This study aimed to assess the potential use of DECT for the functional assessment of the thyroid gland. Thirteen patients with Grave's disease treated at our hospital from May to September 2015 were included in this retrospective study. Before treatments, all subjects had undergone both iodine scintigraphy [three and 24 h after oral administration of 123 I (20 μCi)] and non-enhanced DECT. The region of interests (ROIs) were placed in both lobes of the thyroid glands, and CT values (HU: Hounsfield unit) and iodine concentrations (mg/mL) calculated from DECT images were measured. The correlation between CT values and iodine concentrations from DECT in the thyroid gland was evaluated and then the iodine concentrations were compared with radioactive iodine uptake ratios by thyroid scintigraphy. Mean (±SD) 123 I uptake increased from 46.3 (±22.2) % (range, 11.1-80.1) at 3 h, to 66.5 (±15.2) % (range, 40.0-86.1) at 24 h (p < 0.01). CT values ranged from 34.5 to 98.7 HU [mean: 67.8 (±18.6)], while the iodine concentrations calculated with DECT ranged from 0.0 to 1.3 mg/mL [mean: 0.5 (±0.4)]. A moderate positive correlation between CT values and the calculated iodine concentrations in the thyroid gland was seen (R = 0.429, p < 0.05). A significant negative correlation between 123 I uptake at 3 h and iodine concentration by DECT were seen (R = -0.680, p < 0.05), although no correlation was observed between 123 I uptake at 3 h and CT values (p = 0.087). No correlation was observed between 123 I uptake at 24 h and CT values (p = 0.153) or that between 123 I uptake at 24 h and iodine concentration by DECT (p = 0.073). The negative correlation of 123 I uptake at 3 h with iodine concentration evaluated by DECT was better than that observed with simple CT value. DECT may have a potential role in the evaluation of iodine turnover in hyperthyroid patients.

(18)F-FDG and (18)F-FLT PET/CT imaging in the characterization of mediastinal lymph nodes.

PubMed

Rayamajhi, Sampanna Jung; Mittal, Bhagwant Rai; Maturu, Venkata Nagarjuna; Agarwal, Ritesh; Bal, Amanjit; Dey, Pranab; Shukla, Jaya; Gupta, Dheeraj

2016-04-01

There is currently no single modality for accurate characterization of enlarged mediastinal lymph nodes into benign or malignant. Recently (18)F-fluorothymidine (FLT) has been used as a proliferation marker. In this prospective study, we examined the role of (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) and (18)F-FLT PET/CT in categorizing mediastinal lymph nodes as benign or malignant. A total of 70 consecutive patients with mediastinal lymphadenopathy detected on computed tomography (CT) or chest radiograph underwent whole body (18)F-FLT PET/CT and (18)F-FDG PET/CT (within 1 week of each other). Lymph nodal tracer uptake was determined by calculation of standardized uptake value (SUV) with both the tracers. Results of PET/CT were compared with histopathology of the lymph nodes. Histopathology results showed thirty-seven patients with sarcoidosis, seven patients with tuberculosis, nine patients with non-small cell lung cancer, five patients with Hodgkin's lymphoma and twelve patients with non-Hodgkin's lymphoma. The mean FDG SUVmax of sarcoidosis, tuberculosis, Hodgkin's and non-Hodgkin's lymphoma was 12.7, 13.4, 8.2, and 8.8, respectively, and the mean FLT SUVmax was 6.0, 5.4, 4.4, and 3.8, respectively. It was not possible to characterize mediastinal lymphadenopathy as benign or malignant solely based on FDG SUVmax values (p > 0.05) or FLT SUVmax values (p > 0.05). There was no significant difference in FDG uptake (p > 0.9) or FLT uptake (p > 0.9) between sarcoidosis and tuberculosis. In lung cancer patients, the FDG SUVmax and FLT SUVmax of those lymph nodes with tumor infiltration on biopsy was 6.7 and 3.9, respectively, and those without nodal infiltration was 6.4 and 3.7, respectively, and both the tracers were not able to characterize the nodal status as malignant or benign (p > 0.05). Though (18)F-FLT PET/CT and (18)F-FDG PET/CT reflect different aspects of biology, i.e., proliferation and metabolism, respectively, neither tracer could provide satisfactory categorization of benign and malignant lymph nodes. The results of this study clearly suggest that differentiation of mediastinal nodes into benign and malignant solely based on SUVmax values cannot be relied upon, especially in settings where tuberculosis and sarcoidosis are common.

Effect of symptom-based risk stratification on the costs of managing patients with chronic rhinosinusitis symptoms.

PubMed

Tan, Bruce K; Lu, Guanning; Kwasny, Mary J; Hsueh, Wayne D; Shintani-Smith, Stephanie; Conley, David B; Chandra, Rakesh K; Kern, Robert C; Leung, Randy

2013-11-01

Current symptom criteria poorly predict a diagnosis of chronic rhinosinusitis (CRS) resulting in excessive treatment of patients with presumed CRS. The objective of this study was analyze the positive predictive value of individual symptoms, or symptoms in combination, in patients with CRS symptoms and examine the costs of the subsequent diagnostic algorithm using a decision tree-based cost analysis. We analyzed previously collected patient-reported symptoms from a cross-sectional study of patients who had received a computed tomography (CT) scan of their sinuses at a tertiary care otolaryngology clinic for evaluation of CRS symptoms to calculate the positive predictive value of individual symptoms. Classification and regression tree (CART) analysis then optimized combinations of symptoms and thresholds to identify CRS patients. The calculated positive predictive values were applied to a previously developed decision tree that compared an upfront CT (uCT) algorithm against an empiric medical therapy (EMT) algorithm with further analysis that considered the availability of point of care (POC) imaging. The positive predictive value of individual symptoms ranged from 0.21 for patients reporting forehead pain and to 0.69 for patients reporting hyposmia. The CART model constructed a dichotomous model based on forehead pain, maxillary pain, hyposmia, nasal discharge, and facial pain (C-statistic 0.83). If POC CT were available, median costs ($64-$415) favored using the upfront CT for all individual symptoms. If POC CT was unavailable, median costs favored uCT for most symptoms except intercanthal pain (-$15), hyposmia (-$100), and discolored nasal discharge (-$24), although these symptoms became equivocal on cost sensitivity analysis. The three-tiered CART model could subcategorize patients into tiers where uCT was always favorable (median costs: $332-$504) and others for which EMT was always favorable (median costs -$121 to -$275). The uCT algorithm was always more costly if the nasal endoscopy was positive. Among patients with classic CRS symptoms, the frequency of individual symptoms varied the likelihood of a CRS diagnosis marginally. Only hyposmia, the absence of facial pain, and discolored discharge sufficiently increased the likelihood of diagnosis to potentially make EMT less costly. The development of an evidence-based, multisymptom-based risk stratification model could substantially affect the management costs of the subsequent diagnostic algorithm. © 2013 ARS-AAOA, LLC.

[A case of lung abscess during chemotherapy for testicular tumor].

PubMed

Hayashi, Yujiro; Miyago, Naoki; Takeda, Ken; Yamaguchi, Yuichiro; Nakayama, Masashi; Arai, Yasuyuki; Kakimoto, Ken-ichi; Nishimura, Kazuo

2014-05-01

32-year-old man was seen in a clinic because of prolonged cough and slight-fever. Chest X-ray showed multiple pulmonary nodules, and multiple lung and mediastinal lymph node metastases from right testicular tumor was suspected by positron emission tomography/CT (PET/CT) scan. He was diagnosed with right testicular germ cell tumor (embryonal carcinoma + seminoma, pT2N1M1b), and classified into the intermediate risk group according to International Germ Cell Cancer Collaborative Group. He underwent 4 cycles of chemotherapy with bleomycin, etoposide and cisplatin (BEP therapy). During BEP therapy, sputum with foul odor appeared and chest CT scan revealed lung abscess with a necrotic lesion of metastatic tumor. The lung abscess was treated successfully with antibiotics.

Timing of Radiation Therapy and Chemotherapy After Breast-Conserving Surgery for Node-Positive Breast Cancer: Long-Term Results From International Breast Cancer Study Group Trials VI and VII

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karlsson, Per, E-mail: per.karlsson@oncology.gu.se; Cole, Bernard F.; Price, Karen N.

Purpose: To update the previous report from 2 randomized clinical trials, now with a median follow-up of 16 years, to analyze the effect of radiation therapy timing on local failure and disease-free survival. Patients and Methods: From July 1986 to April 1993, International Breast Cancer Study Group trial VI randomly assigned 1475 pre-/perimenopausal women with node-positive breast cancer to receive 3 or 6 cycles of initial chemotherapy (CT). International Breast Cancer Study Group trial VII randomly assigned 1212 postmenopausal women with node-positive breast cancer to receive tamoxifen for 5 years, or tamoxifen for 5 years with 3 early cycles of initial CT. Formore » patients who received breast-conserving surgery (BCS), radiation therapy (RT) was delayed until initial CT was completed; 4 or 7 months after BCS for trial VI and 2 or 4 months for trial VII. We compared RT timing groups among 433 patients on trial VI and 285 patients on trial VII who received BCS plus RT. Endpoints were local failure, regional/distant failure, and disease-free survival (DFS). Results: Among pre-/perimenopausal patients there were no significant differences in disease-related outcomes. The 15-year DFS was 48.2% in the group allocated 3 months initial CT and 44.9% in the group allocated 6 months initial CT (hazard ratio [HR] 1.12; 95% confidence interval [CI] 0.87-1.45). Among postmenopausal patients, the 15-year DFS was 46.1% in the no-initial-CT group and 43.3% in the group allocated 3 months initial CT (HR 1.11; 95% CI 0.82-1.51). Corresponding HRs for local failures were 0.94 (95% CI 0.61-1.46) in trial VI and 1.51 (95% CI 0.77-2.97) in trial VII. For regional/distant failures, the respective HRs were 1.15 (95% CI 0.80-1.63) and 1.08 (95% CI 0.69-1.68). Conclusions: This study confirms that, after more than 15 years of follow-up, it is reasonable to delay radiation therapy until after the completion of standard CT.« less

Effects of condensed tannins in wrapped silage bales of sainfoin (Onobrychis viciifolia) on in vivo and in situ digestion in sheep.

PubMed

Theodoridou, K; Aufrère, J; Andueza, D; Le Morvan, A; Picard, F; Pourrat, J; Baumont, R

2012-02-01

The objective of this study was to characterize the condensed tannins (CTs) in wrapped silage bales of sainfoin (Onobrychis viciifolia) and examine their potential action on in vivo and in situ digestive characteristics in sheep. Silage was made from sainfoin, cut at two phenological stages. The first phenological stage, at which silage was made, was from the first vegetation cycle at the end of flowering and the second stage silage was made from regrowth, 5 weeks after the first cut, but before flowering. The silages made from the two phenological stages were fed to 12 rumen-fistulated sheep in a crossover design. Of the 12 sheep, six received polyethylene glycol (PEG) to bind with and remove the effects of CT, whereas the other six were dosed with water. Organic matter digestibility, total-tract N digestibility and N (N) balance were measured over 6 days. Kinetic studies were performed on total N, ammonia N (NH3-N) and volatile fatty acids (VFAs) in rumen fluid before and 1.5, 3 and 6 h after feeding. The kinetics of degradation of dry matter and N from Dacron bags suspended in the rumen were also determined. Biological activity of CT (protein-binding capacity) and CT concentration were greater for the silage made from sainfoin at the early flowering stage. Total-tract N digestibility was increased by the addition of PEG (P < 0.001) to the sainfoin silage before flowering (P < 0.001). CTs decreased N excretion in urine (P < 0.05) and increased faecal N excretion (P < 0.001), but had no effect on body N retention, which is beneficial for the animal. Ruminal N degradability was smaller in the presence of active CT (P < 0.001) at both phenological stages; however, soluble N (P = 0.2060) and NH3-N (P = 0.5225) concentrations in rumen fluid remained unchanged. The results of this experiment indicate that CT in the sainfoin retain their ability to affect the nutritive value of preserved forage legumes.

A hybrid approach for fusing 4D-MRI temporal information with 3D-CT for the study of lung and lung tumor motion.

PubMed

Yang, Y X; Teo, S-K; Van Reeth, E; Tan, C H; Tham, I W K; Poh, C L

2015-08-01

Accurate visualization of lung motion is important in many clinical applications, such as radiotherapy of lung cancer. Advancement in imaging modalities [e.g., computed tomography (CT) and MRI] has allowed dynamic imaging of lung and lung tumor motion. However, each imaging modality has its advantages and disadvantages. The study presented in this paper aims at generating synthetic 4D-CT dataset for lung cancer patients by combining both continuous three-dimensional (3D) motion captured by 4D-MRI and the high spatial resolution captured by CT using the authors' proposed approach. A novel hybrid approach based on deformable image registration (DIR) and finite element method simulation was developed to fuse a static 3D-CT volume (acquired under breath-hold) and the 3D motion information extracted from 4D-MRI dataset, creating a synthetic 4D-CT dataset. The study focuses on imaging of lung and lung tumor. Comparing the synthetic 4D-CT dataset with the acquired 4D-CT dataset of six lung cancer patients based on 420 landmarks, accurate results (average error <2 mm) were achieved using the authors' proposed approach. Their hybrid approach achieved a 40% error reduction (based on landmarks assessment) over using only DIR techniques. The synthetic 4D-CT dataset generated has high spatial resolution, has excellent lung details, and is able to show movement of lung and lung tumor over multiple breathing cycles.

Dual energy spectral CT imaging for the evaluation of small hepatocellular carcinoma microvascular invasion.

PubMed

Yang, Chuang-Bo; Zhang, Shuang; Jia, Yong-Jun; Yu, Yong; Duan, Hai-Feng; Zhang, Xi-Rong; Ma, Guang-Ming; Ren, Chenglong; Yu, Nan

2017-10-01

To study the clinical value of dual-energy spectral CT in the quantitative assessment of microvascular invasion of small hepatocellular carcinoma. This study was approved by our ethics committee. 50 patients with small hepatocellular carcinoma who underwent contrast enhanced spectral CT in arterial phase (AP) and portal venous phase (VP) were enrolled. Tumour CT value and iodine concentration (IC) were measured from spectral CT images. The slope of spectral curve, normalized iodine concentration (NIC, to abdominal aorta) and ratio of IC difference between AP and VP (RIC AP-VP : [RIC AP-VP =(IC AP -IC VP )/IC AP ]) were calculated. Tumours were identified as either with or without microvascular invasion based on pathological results. Measurements were statistically compared using independent samples t test. The receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic performance of tumours microvascular invasion assessment. The 70keV images were used to simulate the results of conventional CT scans for comparison. 56 small hepatocellular carcinomas were detected with 37 lesions (Group A) with microvascular invasion and 19 (Group B) without. There were significant differences in IC, NIC and slope in AP and RIC AP-VP between Group A (2.48±0.70mg/ml, 0.23±0.05, 3.39±1.01 and 0.28±0.16) and Group B (1.65±0.47mg/ml, 0.15±0.05, 2.22±0.64 and 0.03±0.24) (all p<0.05). Using 0.188 as the threshold for NIC, one could obtain an area-under-curve (AUC) of 0.87 in ROC to differentiate between tumours with and without microvascular invasion. AUC was 0.71 with CT value at 70keV and improved to 0.81 at 40keV. Dual-energy Spectral CT provides additional quantitative parameters than conventional CT to improve the differentiation between small hepatocellular carcinoma with and without microvascular invasion. Quantitative iodine concentration measurement in spectral CT may be used to provide a new method to improve the evaluation for small hepatocellular carcinoma microvascular invasion. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparative diagnostic value of 18F-fluoride PET-CT versus MRI for skull-base bone invasion in nasopharyngeal carcinoma.

PubMed

Le, Yali; Chen, Yu; Zhou, Fan; Liu, Guangfu; Huang, Zhanwen; Chen, Yue

2016-10-01

This study compared the diagnostic value of F-fluoride PET-computed tomography (PET-CT) and MRI in skull-base bone erosion in nasopharyngeal carcinoma (NPC) patients. A total of 93 patients with biopsy-confirmed NPC were enrolled, including 68 men and 25 women between 23 and 74 years of age. All patients were evaluated by both F-fluoride PET-CT and MRI, and the interval between the two imaging examinations was less than 20 days. The patients received no treatment either before or between scans. The studies were interpreted by two nuclear medicine physicians or two radiologists with more than 10 years of professional experience who were blinded to both the diagnosis and the results of the other imaging studies. The reference standard was skull-base bone erosion at a 20-week follow-up imaging study. On the basis of the results of the follow-up imaging studies, 52 patients showed skull-base bone erosion. The numbers of true positives, false positives, true negatives, and false negatives with F-fluoride PET-CT were 49, 4, 37, and 3, respectively. The numbers of true positives, false positives, true negatives, and false negatives with MRI were 46, 5, 36, and 6, respectively. The sensitivity, specificity, and crude accuracy of F-fluoride PET-CT were 94.23, 90.24, and 92.47%, respectively; for MRI, these values were 88.46, 87.80, and 88.17%. Of the 52 patients, 43 showed positive findings both on F-fluoride PET-CT and on MRI. Within the patient cohort, F-fluoride PET-CT and MRI detected 178 and 135 bone lesions, respectively. Both F-fluoride PET-CT and MRI have high sensitivity, specificity, and crude accuracy for detecting skull-base bone invasion in patients with NPC. F-fluoride PET-CT detected more lesions than did MRI in the skull-base bone. This suggests that F-fluoride PET-CT has a certain advantage in evaluating the skull-base bone of NPC patients. Combining the two methods could improve the diagnostic accuracy of skull-base bone invasion for NPC.

Computed tomography scan diagnosis of occult groin hernia.

PubMed

Garvey, J F W

2012-06-01

The value of computed tomography (CT) for the diagnosis of clinically occult (hidden) groin hernia was assessed in a series of patients presenting with undiagnosed groin pain. A total of 158 consecutive patients presenting over a period of 5 years with undiagnosed groin pain or lower abdominal pain and negative or equivocal clinical findings were radiologically assessed with non-contrast CT. The decision to manage operatively or conservatively was then based on a combination of the clinical and CT findings. Outcomes were assessed at 10 years follow-up. The study cohort comprised 158 patients presenting with groin or lower abdominal pain and/or swelling, and was studied prospectively. Seven of these patients were re-investigated at a later date after developing new pain on either the ipsilateral or contralateral side, giving a total of 165 CT examinations. One-third of cases (54) had clinically occult groin hernias and most of the remaining cases had diagnoses that could be managed non-operatively. Of those who came to surgery, the pre-operative CT diagnosis of hernia had a positive predictive value (PPV) of 92% and a negative predictive value (NPV) of 96% (overall accuracy 94%). Lipoma of the spermatic cord was responsible for three of five false-positive CT results. The concept of sports hernia/groin disruption injury (GDI) was encountered, and this entity is discussed in this paper. In the group of patients without hernia findings on CT, the most common diagnoses were rectus abdominis and/or pyramidalis muscle injury which could be treated by physiotherapy (22%), GDI (16%), post-surgical problems (14%), miscellaneous (20%) and 'no abnormality' was identified in 15%. Overall, there were 111 patients with a 'non-hernia' CT diagnosis, of which urological, gynaecological, gastrointestinal and neuralgia contributed to the non-musculoskeletal diagnosis. This prospective non-contrast CT study of patients with undiagnosed chronic groin pain detected the majority of occult hernias requiring surgical intervention. These results suggest that CT can be a useful adjunct to the evaluation of patients presenting with chronic undiagnosed groin pain, but that experienced clinical judgment remains a critical element in the diagnostic pathway.

A comparative analysis of the dependences of the hemodynamic parameters on changes in ROI's position in perfusion CT scans

NASA Astrophysics Data System (ADS)

Choi, Yong-Seok; Cho, Jae-Hwan; Namgung, Jang-Sun; Kim, Hyo-Jin; Yoon, Dae-Young; Lee, Han-Joo

2013-05-01

This study performed a comparative analysis of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and mean time-to-peak (TTP) obtained by changing the region of interest's (ROI) anatomical positions, during CT brain perfusion. We acquired axial source images of perfusion CT from 20 patients undergoing CT perfusion exams due to brain trauma. Subsequently, the CBV, CBF, MTT, and TTP values were calculated through data-processing of the perfusion CT images. The color scales for the CBV, CBF, MTT, and TTP maps were obtained using the image data. Anterior cerebral artery (ACA) was taken as the standard ROI for the calculations of the perfusion values. Differences in the hemodynamic average values were compared in a quantitative analysis by placing ROI and the dividing axial images into proximal, middle, and distal segments anatomically. By performing the qualitative analysis using a blind test, we observed changes in the sensory characteristics by using the color scales of the CBV, CBF, and MTT maps in the proximal, middle, and distal segments. According to the qualitative analysis, no differences were found in CBV, CBF, MTT, and TTP values of the proximal, middle, and distal segments and no changes were detected in the color scales of the the CBV, CBF, MTT, and TTP maps in the proximal, middle, and distal segments. We anticipate that the results of the study will useful in assessing brain trauma patients using by perfusion imaging.

Utility of spiral CAT scan in the follow-up of patients with pulmonary Langerhans cell histiocytosis.

PubMed

Abbritti, M; Mazzei, M A; Bargagli, E; Refini, R M; Penza, F; Perari, M G; Volterrani, L; Rottoli, P

2012-08-01

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare disease that occurs almost exclusively in smokers, generally young adults between 20 and 40 years old. Prognostic biomarkers of the disease are lacking. This study describes the clinical-radiological features of a group of PLCH patients and applies a semi-quantitative CT score of the chest to verify the prognostic value of radiological findings in this disease. Clinical-radiological and immunological data from 12 Caucasian patients (6M, 7 smokers and 5 ex-smokers, mean age 36±8 years) were recorded at onset and after a follow-up period of 4 years. Application of the semi-quantitative CT score revealed a prevalently cystic pattern at onset and follow-up in the majority of the patients. Patients with a prevalently nodular pattern developed cystic lesions during follow-up. Interestingly, significant correlations were found between the extent of cystic lesions and DLCO values at onset (time 0: p<0.05) and at the end of follow-up (time 1, p<0.05) and with FEV1 values at time 0 (p<0.05) and time 1 (p<0.05). Patients with progressive functional decline were those with CT evidence of severe cystic alterations. The results suggest that high resolution CT scan of the chest is mandatory for characterizing PLCH patients at diagnosis and during follow-up. The proposed CT score of the chest showed potential prognostic value. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Distribution of CO2 parameters in the Western Tropical Atlantic Ocean

NASA Astrophysics Data System (ADS)

Bonou, Frédéric Kpèdonou; Noriega, Carlos; Lefèvre, Nathalie; Araujo, Moacyr

2016-03-01

The variability of sea surface Total Alkalinity (TA) and sea surface Total Inorganic Carbon (CT) is examined using all available data in the western tropical Atlantic (WTA: 20°S-20°N, 60°W-20°W). Lowest TA and CT are observed for the region located between 0°N-15°N/60°W-50°W and are explained by the influence of the Amazon plume during boreal summer. In the southern part of the area, 20°S-10°S/40°W-60°W, the highest values of TA and CT are linked to the CO2-rich waters due to the equatorial upwelling, which are transported by the South Equatorial Current (SEC) flowing from the African coast to the Brazilian shore. An increase of CT of 0.9 ± 0.3 μmol kg-1yr-1 has been observed in the SEC region and is consistent with previous published estimates. A revised CT-Sea Surface Salinity (SSS) relationship is proposed for the WTA to take into account the variability of CT at low salinities. This new CT-SSS relationship together with a published TA-SSS relationship allow to calculate pCO2 values that compare well with observed pCO2 (R2 = 0.90).

Statistical distributions of ultra-low dose CT sinograms and their fundamental limits

NASA Astrophysics Data System (ADS)

Lee, Tzu-Cheng; Zhang, Ruoqiao; Alessio, Adam M.; Fu, Lin; De Man, Bruno; Kinahan, Paul E.

2017-03-01

Low dose CT imaging is typically constrained to be diagnostic. However, there are applications for even lowerdose CT imaging, including image registration across multi-frame CT images and attenuation correction for PET/CT imaging. We define this as the ultra-low-dose (ULD) CT regime where the exposure level is a factor of 10 lower than current low-dose CT technique levels. In the ULD regime it is possible to use statistically-principled image reconstruction methods that make full use of the raw data information. Since most statistical based iterative reconstruction methods are based on the assumption of that post-log noise distribution is close to Poisson or Gaussian, our goal is to understand the statistical distribution of ULD CT data with different non-positivity correction methods, and to understand when iterative reconstruction methods may be effective in producing images that are useful for image registration or attenuation correction in PET/CT imaging. We first used phantom measurement and calibrated simulation to reveal how the noise distribution deviate from normal assumption under the ULD CT flux environment. In summary, our results indicate that there are three general regimes: (1) Diagnostic CT, where post-log data are well modeled by normal distribution. (2) Lowdose CT, where normal distribution remains a reasonable approximation and statistically-principled (post-log) methods that assume a normal distribution have an advantage. (3) An ULD regime that is photon-starved and the quadratic approximation is no longer effective. For instance, a total integral density of 4.8 (ideal pi for 24 cm of water) for 120kVp, 0.5mAs of radiation source is the maximum pi value where a definitive maximum likelihood value could be found. This leads to fundamental limits in the estimation of ULD CT data when using a standard data processing stream

[Impact of exposure dose reduction of radiation treatment planning CT using low tube voltage technique].

PubMed

Kouno, Takuya; Kuga, Noriyuki; Enzaki, Masahiro; Yamashita, Yuuki; Kitazato, Yumiko; Shimotabira, Haruhiko; Jinnouchi, Takashi; Kusuhara, Kazuo; Kawamura, Shinji

2015-04-01

The aim of this study was to reduce the exposed dose of radiotherapy treatment planning computed tomography (CT) by using low tube voltage technique. We used tube voltages of 80 kV, 100 kV, and 120 kV, respectively. First, we evaluated exposure dose with CT dose index (CTDI) for each voltage. Second, we compared image quality indexes such as modulation transfer function (MTF), noise power spectrum (NPS), and contrast to noise ratio (CNR) of phantom images with each voltage. Third, CT to electron density tables were measured in three voltages and monitor unit value was calculated along with clinical cases. Finally, CT surface exposed dose of chest skin was measured by thermoluminescent dosimeter (TLD). In image evaluation MTF and NPS were approximately equal; CNR slightly decreased, 2.0% for 100 kV. We performed check radiation dose accuracy for each tube voltage with each model phantom. As a result, the difference of MU value was not accepted. Finally, compared with 120 kV, CTDIvol and TLD value showed markedly decreased radiation dose, 60% for 80 kV and 30% for 100 kV. Using a technique with low tube voltages, especially 100 kV, is useful in radiotherapy treatment planning to obtain 20% dose reduction without compromising 120 kV image quality.

Diagnostic Ability of FDG-PET/CT in the Detection of Malignant Pleural Effusion.

PubMed

Nakajima, Reiko; Abe, Koichiro; Sakai, Shuji

2015-07-01

We investigated the role of F-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) for the differential diagnosis of malignant and benign pleural effusion. We studied 36 consecutive patients with histologically proven cancer (excluding malignant mesothelioma) who underwent FDG-PET/CT for suspected malignant pleural effusion. Fourteen patients had cytologically proven malignant pleural effusion and the other 22 patients had either negative cytology or clinical follow-up, which confirmed the benign etiology. We examined the maximum standardized uptake values (SUV max) of pleural effusion and the target-to-normal tissue ratio (TNR), calculated as the ratio of the pleural effusion SUV max to the SUV mean of the normal tissues (liver, spleen, 12th thoracic vertebrae [Th12], thoracic aorta, and spinalis muscle). We also examined the size and density (in Hounsfield units) of the pleural effusion and pleural abnormalities on CT images. TNR (Th12) and increased pleural FDG uptake compared to background blood pool were significantly more frequent in cases with malignant pleural effusion (P < 0.05 for both). The cutoff TNR (Th12) value of >0.95 was the most accurate; the sensitivity, specificity, and accuracy for this value were 93%, 68%, and 75%, respectively. FDG-PET/CT can be a useful method for the differential diagnosis of malignant and benign pleural effusion.

Factors affecting ANKOM™ fiber analysis of forage and browse varying in condensed tannin concentration.

PubMed

Terrill, Thomas H; Wolfe, Richard M; Muir, James P

2010-12-01

Browse species containing condensed tannins (CTs) are an important source of nutrition for grazing/browsing livestock and wildlife in many parts of the world, but information on fiber concentration and CT-fiber interactions for these plants is lacking. Ten forage or browse species with a range of CT concentrations were oven dried and freeze dried and then analyzed for ash-corrected neutral detergent fiber (NDFom) and corrected acid detergent fiber (ADFom) using separate samples (ADFSEP) and sequential NDF-ADF analysis (ADFSEQ) with the ANKOM™ fiber analysis system. The ADFSEP and ADFSEQ residues were then analyzed for nitrogen (N) concentration. Oven drying increased (P < 0.05) fiber concentrations with some species, but not with others. For high-CT forage and browse species, ADFSEP concentrations were greater (P < 0.05) than NDFom values and approximately double the ADFSEQ values. Nitrogen concentration was greater (P < 0.05) in ADFSEP than ADFSEQ residues, likely due to precipitation with CTs. Sequential NDF-ADF analysis gave more realistic values and appeared to remove most of the fiber residue contaminants in CT forage samples. Freeze drying samples with sequential NDF-ADF analysis is recommended in the ANKOM™ fiber analysis system with CT-containing forage and browse species. Copyright © 2010 Society of Chemical Industry.

Consistent evaluation of GOSAT, SCIAMACHY, carbontracker, and MACC through comparisons to TCCON

DOE PAGES

Kulawik, S. S.; Wunch, D.; O'Dell, C.; ...

2015-06-22

Consistent validation of satellite CO 2 estimates is a prerequisite for using multiple satellite CO 2 measurements for joint flux inversion, and for establishing an accurate long-term atmospheric CO 2 data record. We focus on validating model and satellite observation attributes that impact flux estimates and CO 2 assimilation, including accurate error estimates, correlated and random errors, overall biases, biases by season and latitude, the impact of coincidence criteria, validation of seasonal cycle phase and amplitude, yearly growth, and daily variability. We evaluate dry air mole fraction (X CO 2) for GOSAT (ACOS b3.5) and SCIAMACHY (BESD v2.00.08) as wellmore » as the CarbonTracker (CT2013b) simulated CO 2 mole fraction fields and the MACC CO 2 inversion system (v13.1) and compare these to TCCON observations (GGG2014). We find standard deviations of 0.9 ppm, 0.9, 1.7, and 2.1 ppm versus TCCON for CT2013b, MACC, GOSAT, and SCIAMACHY, respectively, with the single target errors 1.9 and 0.9 times the predicted errors for GOSAT and SCIAMACHY, respectively. When satellite data are averaged and interpreted according to error 2 = a 2+ b 2 / n (where n are the number of observations averaged, a are the systematic (correlated) errors, and b are the random (uncorrelated) errors), we find that the correlated error term a = 0.6 ppm and the uncorrelated error term b = 1.7 ppm for GOSAT and a = 1.0 ppm, b = 1.4 ppm for SCIAMACHY regional averages. Biases at individual stations have year-to-year variability of ~ 0.3 ppm, with biases larger than the TCCON predicted bias uncertainty of 0.4 ppm at many stations. Using fitting software, we find that GOSAT underpredicts the seasonal cycle amplitude in the Northern Hemisphere (NH) between 46–53° N. In the Southern Hemisphere (SH), CT2013b underestimates the seasonal cycle amplitude. Biases are calculated for 3-month intervals and indicate the months that contribute to the observed amplitude differences. The seasonal cycle phase indicates whether a dataset or model lags another dataset in time. We calculate this at a subset of stations where there is adequate satellite data, and find that the GOSAT retrieved phase improves substantially over the prior and the SCIAMACHY retrieved phase improves substantially for 2 of 7 sites. The models reproduce the measured seasonal cycle phase well except for at Lauder125 (CT2013b), Darwin (MACC), and Izana (+ 10 days, CT2013b), as for Bremen and Four Corners, which are highly influenced by local effects. We compare the variability within one day between TCCON and models in JJA; there is correlation between 0.2 and 0.8 in the NH, with models showing 10–100 % the variability of TCCON at different stations (except Bremen and Four Corners which have no variability compared to TCCON) and CT2013b showing more variability than MACC. This paper highlights findings that provide inputs to estimate flux errors in model assimilations, and places where models and satellites need further investigation, e.g. the SH for models and 45–67° N for GOSAT« less

Reducing Variability in Orthogonal Reformatted Image Quality Associated With Axial Long-z-Axis CT Angiography.

PubMed

Stein, Erica B; Liu, Peter S; Kazerooni, Ella A; Barber, Karen; Davenport, Matthew S

2016-12-01

The objective of our study was to reduce variation in image quality of orthogonal reformatted images generated from long-z-axis CT angiography (CTA) studies of the upper and lower extremities. Upper and lower extremity CTA studies were targeted at a single health care system. A correctly performed CTA examination was defined as one that met the following three criteria: Sagittal and coronal reformats were obtained, a high-resolution matrix greater than 512 × 512 was used, and reformatted images were available in a distance-measurable format. Baseline data were collected from February 1, 2014, through September 30, 2014. Corrective actions were implemented during three consecutive plan-do-check-act (PDCA) cycles from October 1, 2014, through July 31, 2015, that addressed human, technical, and systematic variations. A 3-month maintenance period followed in which no intervention was performed. Longitudinal data were analyzed monthly using a statistical process control chart (p-chart). The total number of long-z-axis extremity CTA studies analyzed was as follows: 351 CTA studies were analyzed at baseline, 94 at the first PDCA cycle, 92 at the second PDCA cycle, 114 at the third PDCA cycle, and 138 during the maintenance period. The monthly rate of correctly performed studies ranged from 7% to 51% (mean, 38% ± 13% [SD]) during the baseline period, 32-59% (mean, 46% ± 14%) during the first PDCA cycle, 40-81% (mean, 61% ± 21%) during the second PDCA cycle, and 80-82% (mean, 81% ± 0.9%) during the third PDCA cycle. The monthly rate improved to 90-91% (mean, 91% ± 0.5%) during the maintenance period. The upper and lower control limits of the p-chart were upshifted after the second and third PDCA cycles. Correcting systematic and technical variations led to the greatest improvements in reformat accuracy. Obtaining consistently and correctly reformatted images from long-z-axis CTA studies is achievable using iterative PDCA cycles.

Assessment of ultrasonography and computed tomography for the evaluation of unilateral orbital disease in dogs.

PubMed

Boroffka, Susanne A E B; Verbruggen, Anne-Marie; Grinwis, Guy C M; Voorhout, George; Barthez, Paul Y

2007-03-01

To describe clinical, ultrasonographic, and computed tomographic (CT) features of confirmed neoplastic and nonneoplastic disease in dogs with unilateral orbital diseases, determine criteria to differentiate between the 2 conditions, and assess the relative value of ultrasonography and CT for the differential diagnosis of these 2 conditions. Prospective study. 29 dogs with unilateral neoplastic orbital disease and 16 dogs with unilateral nonneoplastic orbital disease. Clinical history and results of physical and ophthalmologic examinations were recorded. Ultrasonographic and CT images were evaluated, and discriminating factors were identified to differentiate neoplastic from nonneoplastic diseases. Diagnostic value of ultrasonography and CT was assessed. Dogs with neoplastic disease were significantly older; had clinical signs for a longer time before initial examination; had more progressive onset of clinical signs; and more frequently had protrusion of the nictitating membrane, fever, and anorexia. The most discriminating factor for both imaging modalities was delineation of the margins (odds ratio was 41.7 for ultrasonography and 45 for CT), with neoplastic lesions clearly delineated more often. Ultrasonographically, neoplastic lesions were more frequently hypoechoic and homogeneous, with indentation of the globe and bone involvement evident more frequently than for nonneoplastic lesions. Mineralization was detected only with neoplasia. Fluctuant fluid was seen more frequently in dogs with nonneoplastic disease. Computed tomography more frequently revealed extraorbital involvement. Diagnostic value was similar for both imaging modalities. Ultrasonography and CT are valuable imaging modalities to assist in differentiating neoplastic from nonneoplastic unilateral orbital disease in dogs.

Lung texture in serial thoracic CT scans: Assessment of change introduced by image registration1

PubMed Central

Cunliffe, Alexandra R.; Al-Hallaq, Hania A.; Labby, Zacariah E.; Pelizzari, Charles A.; Straus, Christopher; Sensakovic, William F.; Ludwig, Michelle; Armato, Samuel G.

2012-01-01

Purpose: The aim of this study was to quantify the effect of four image registration methods on lung texture features extracted from serial computed tomography (CT) scans obtained from healthy human subjects. Methods: Two chest CT scans acquired at different time points were collected retrospectively for each of 27 patients. Following automated lung segmentation, each follow-up CT scan was registered to the baseline scan using four algorithms: (1) rigid, (2) affine, (3) B-splines deformable, and (4) demons deformable. The registration accuracy for each scan pair was evaluated by measuring the Euclidean distance between 150 identified landmarks. On average, 1432 spatially matched 32 × 32-pixel region-of-interest (ROI) pairs were automatically extracted from each scan pair. First-order, fractal, Fourier, Laws’ filter, and gray-level co-occurrence matrix texture features were calculated in each ROI, for a total of 140 features. Agreement between baseline and follow-up scan ROI feature values was assessed by Bland–Altman analysis for each feature; the range spanned by the 95% limits of agreement of feature value differences was calculated and normalized by the average feature value to obtain the normalized range of agreement (nRoA). Features with small nRoA were considered “registration-stable.” The normalized bias for each feature was calculated from the feature value differences between baseline and follow-up scans averaged across all ROIs in every patient. Because patients had “normal” chest CT scans, minimal change in texture feature values between scan pairs was anticipated, with the expectation of small bias and narrow limits of agreement. Results: Registration with demons reduced the Euclidean distance between landmarks such that only 9% of landmarks were separated by ≥1 mm, compared with rigid (98%), affine (95%), and B-splines (90%). Ninety-nine of the 140 (71%) features analyzed yielded nRoA > 50% for all registration methods, indicating that the majority of feature values were perturbed following registration. Nineteen of the features (14%) had nRoA < 15% following demons registration, indicating relative feature value stability. Student's t-tests showed that the nRoA of these 19 features was significantly larger when rigid, affine, or B-splines registration methods were used compared with demons registration. Demons registration yielded greater normalized bias in feature value change than B-splines registration, though this difference was not significant (p = 0.15). Conclusions: Demons registration provided higher spatial accuracy between matched anatomic landmarks in serial CT scans than rigid, affine, or B-splines algorithms. Texture feature changes calculated in healthy lung tissue from serial CT scans were smaller following demons registration compared with all other algorithms. Though registration altered the values of the majority of texture features, 19 features remained relatively stable after demons registration, indicating their potential for detecting pathologic change in serial CT scans. Combined use of accurate deformable registration using demons and texture analysis may allow for quantitative evaluation of local changes in lung tissue due to disease progression or treatment response. PMID:22894392

Demons deformable registration of CT and cone-beam CT using an iterative intensity matching approach

PubMed Central

Nithiananthan, Sajendra; Schafer, Sebastian; Uneri, Ali; Mirota, Daniel J.; Stayman, J. Webster; Zbijewski, Wojciech; Brock, Kristy K.; Daly, Michael J.; Chan, Harley; Irish, Jonathan C.; Siewerdsen, Jeffrey H.

2011-01-01

Purpose: A method of intensity-based deformable registration of CT and cone-beam CT (CBCT) images is described, in which intensity correction occurs simultaneously within the iterative registration process. The method preserves the speed and simplicity of the popular Demons algorithm while providing robustness and accuracy in the presence of large mismatch between CT and CBCT voxel values (“intensity”). Methods: A variant of the Demons algorithm was developed in which an estimate of the relationship between CT and CBCT intensity values for specific materials in the image is computed at each iteration based on the set of currently overlapping voxels. This tissue-specific intensity correction is then used to estimate the registration output for that iteration and the process is repeated. The robustness of the method was tested in CBCT images of a cadaveric head exhibiting a broad range of simulated intensity variations associated with x-ray scatter, object truncation, and∕or errors in the reconstruction algorithm. The accuracy of CT-CBCT registration was also measured in six real cases, exhibiting deformations ranging from simple to complex during surgery or radiotherapy guided by a CBCT-capable C-arm or linear accelerator, respectively. Results: The iterative intensity matching approach was robust against all levels of intensity variation examined, including spatially varying errors in voxel value of a factor of 2 or more, as can be encountered in cases of high x-ray scatter. Registration accuracy without intensity matching degraded severely with increasing magnitude of intensity error and introduced image distortion. A single histogram match performed prior to registration alleviated some of these effects but was also prone to image distortion and was quantifiably less robust and accurate than the iterative approach. Within the six case registration accuracy study, iterative intensity matching Demons reduced mean TRE to (2.5±2.8) mm compared to (3.5±3.0) mm with rigid registration. Conclusions: A method was developed to iteratively correct CT-CBCT intensity disparity during Demons registration, enabling fast, intensity-based registration in CBCT-guided procedures such as surgery and radiotherapy, in which CBCT voxel values may be inaccurate. Accurate CT-CBCT registration in turn facilitates registration of multimodality preoperative image and planning data to intraoperative CBCT by way of the preoperative CT, thereby linking the intraoperative frame of reference to a wealth of preoperative information that could improve interventional guidance. PMID:21626913

Demons deformable registration of CT and cone-beam CT using an iterative intensity matching approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nithiananthan, Sajendra; Schafer, Sebastian; Uneri, Ali

2011-04-15

Purpose: A method of intensity-based deformable registration of CT and cone-beam CT (CBCT) images is described, in which intensity correction occurs simultaneously within the iterative registration process. The method preserves the speed and simplicity of the popular Demons algorithm while providing robustness and accuracy in the presence of large mismatch between CT and CBCT voxel values (''intensity''). Methods: A variant of the Demons algorithm was developed in which an estimate of the relationship between CT and CBCT intensity values for specific materials in the image is computed at each iteration based on the set of currently overlapping voxels. This tissue-specificmore » intensity correction is then used to estimate the registration output for that iteration and the process is repeated. The robustness of the method was tested in CBCT images of a cadaveric head exhibiting a broad range of simulated intensity variations associated with x-ray scatter, object truncation, and/or errors in the reconstruction algorithm. The accuracy of CT-CBCT registration was also measured in six real cases, exhibiting deformations ranging from simple to complex during surgery or radiotherapy guided by a CBCT-capable C-arm or linear accelerator, respectively. Results: The iterative intensity matching approach was robust against all levels of intensity variation examined, including spatially varying errors in voxel value of a factor of 2 or more, as can be encountered in cases of high x-ray scatter. Registration accuracy without intensity matching degraded severely with increasing magnitude of intensity error and introduced image distortion. A single histogram match performed prior to registration alleviated some of these effects but was also prone to image distortion and was quantifiably less robust and accurate than the iterative approach. Within the six case registration accuracy study, iterative intensity matching Demons reduced mean TRE to (2.5{+-}2.8) mm compared to (3.5{+-}3.0) mm with rigid registration. Conclusions: A method was developed to iteratively correct CT-CBCT intensity disparity during Demons registration, enabling fast, intensity-based registration in CBCT-guided procedures such as surgery and radiotherapy, in which CBCT voxel values may be inaccurate. Accurate CT-CBCT registration in turn facilitates registration of multimodality preoperative image and planning data to intraoperative CBCT by way of the preoperative CT, thereby linking the intraoperative frame of reference to a wealth of preoperative information that could improve interventional guidance.« less

False Positive Positron Emission Tomography / Computed Tomography Scans in Treated Head and Neck Cancers

PubMed Central

Cheung, Michael K; Ong, Shawn Y; Goyal, Uma; Wertheim, Betsy C; Hsu, Charles C

2017-01-01

Objective Positron emission tomography/computed tomography (PET/CT) imaging for head and neck cancers (HNC) is commonly utilized for post-treatment assessment. Though PET/CT in this setting has been reported to have high negative predictive values (> 90%), positive predictive values have been reported at approximately 50%, leading to high rates of false positivity (FP) and troubling management decisions for both patient and practitioner. The objective of this study was to identify patient, disease, treatment and imaging factors that might be associated with a higher likelihood of FP on initial post-treatment PET/CT imaging for patients treated for HNC.  Materials and methods A retrospective chart review was performed on 84 patients treated for HNC who received radiation therapy (RT) as part of their overall management from October 2005 to August 2013. Of the patients screened, 19 were found to have mucosally based squamous cell carcinoma (SCC) with positive initial post-treatment PET/CT studies (23%). Fisher’s exact test was used to analyze the association between categorical variables and FP, including patient's gender, disease laterality, primary tumor site and stage, nodal and overall stage, high dose RT fraction size, number of RT fractions completed, total RT dose, biologically effective dose and timing of PET/CT acquisition. Wilcoxon rank-sum test was used to analyze the association between continuous variables and FP, including patient age, total elapsed days of RT, an amount of infused fluorodeoxyglucose 18F-FDG, pre-PET/CT serum glucose levels, and maximum standardized uptake value SUVmax. Statistically significant findings were those that were deemed p <0.05. Results Among patients with positive initial post-treatment PET/CT scans for treated HNC, there was a lower proportion of higher primary disease stage associated with FP versus true positivity (T-stage 3-4: 20 vs 78%, respectively, p=0.023). We also discovered that 50% of patients that underwent confirmation for FP findings suffered serious complications as a direct consequence of invasive exploratory procedures. Conclusions Although PET/CT is known for its exceptional negative predictive value (> 90%) in the post-treatment setting for HNC, high rates of FP remains a clinical challenge. Our study suggests that tumor stage (T-stage) may impact FP rates in positive initial post-treatment PET/CT scans. We recommend careful multidisciplinary discussion regarding positive PET/CT studies in the post-treatment setting for HNC, particularly if invasive intervention is considered. PMID:28497009

Can integrated 18F-FDG PET/MR replace sentinel lymph node resection in malignant melanoma?

PubMed

Schaarschmidt, Benedikt Michael; Grueneisen, Johannes; Stebner, Vanessa; Klode, Joachim; Stoffels, Ingo; Umutlu, Lale; Schadendorf, Dirk; Heusch, Philipp; Antoch, Gerald; Pöppel, Thorsten Dirk

2018-06-06

To compare the sensitivity and specificity of 18F-fluordesoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT), 18F-FDG PET/magnetic resonance (18F-FDG PET/MR) and 18F-FDG PET/MR including diffusion weighted imaging (DWI) in the detection of sentinel lymph node metastases in patients suffering from malignant melanoma. Fifty-two patients with malignant melanoma (female: n = 30, male: n = 22, mean age 50.5 ± 16.0 years, mean tumor thickness 2.28 ± 1.97 mm) who underwent 18F-FDG PET/CT and subsequent PET/MR & DWI for distant metastasis staging were included in this retrospective study. After hybrid imaging, lymphoscintigraphy including single photon emission computed tomography/CT (SPECT/CT) was performed to identify the sentinel lymph node prior to sentinel lymph node biopsy (SLNB). In a total of 87 sentinel lymph nodes in 64 lymph node basins visible on SPECT/CT, 17 lymph node metastases were detected by histopathology. In separate sessions PET/CT, PET/MR, and PET/MR & DWI were assessed for sentinel lymph node metastases by two independent readers. Discrepant results were resolved in a consensus reading. Sensitivities, specificities, positive predictive values and negative predictive values were calculated with histopathology following SPECT/CT guided SLNB as a reference standard. Compared with histopathology, lymph nodes were true positive in three cases, true negative in 65 cases, false positive in three cases and false negative in 14 cases in PET/CT. PET/MR was true positive in four cases, true negative in 63 cases, false positive in two cases and false negative in 13 cases. Hence, we observed a sensitivity, specificity, positive predictive value and negative predictive value of 17.7, 95.6, 50.0 and 82.3% for PET/CT and 23.5, 96.9, 66.7 and 82.3% for PET/MR. In DWI, 56 sentinel lymph node basins could be analyzed. Here, the additional analysis of DWI led to two additional false positive findings, while the number of true positive findings could not be increased. In conclusion, integrated 18F-FDG PET/MR does not reliably differentiate N-positive from N-negative melanoma patients. Additional DWI does not increase the sensitivity of 18F-FDG PET/MR. Hence, sentinel lymph node biopsy cannot be replaced by 18F-FDG-PE/MR or 18F-FDG-PET/CT.

Quantitative computed tomography for the prediction of pulmonary function after lung cancer surgery: a simple method using simulation software.

PubMed

Ueda, Kazuhiro; Tanaka, Toshiki; Li, Tao-Sheng; Tanaka, Nobuyuki; Hamano, Kimikazu

2009-03-01

The prediction of pulmonary functional reserve is mandatory in therapeutic decision-making for patients with resectable lung cancer, especially those with underlying lung disease. Volumetric analysis in combination with densitometric analysis of the affected lung lobe or segment with quantitative computed tomography (CT) helps to identify residual pulmonary function, although the utility of this modality needs investigation. The subjects of this prospective study were 30 patients with resectable lung cancer. A three-dimensional CT lung model was created with voxels representing normal lung attenuation (-600 to -910 Hounsfield units). Residual pulmonary function was predicted by drawing a boundary line between the lung to be preserved and that to be resected, directly on the lung model. The predicted values were correlated with the postoperative measured values. The predicted and measured values corresponded well (r=0.89, p<0.001). Although the predicted values corresponded with values predicted by simple calculation using a segment-counting method (r=0.98), there were two outliers whose pulmonary functional reserves were predicted more accurately by CT than by segment counting. The measured pulmonary functional reserves were significantly higher than the predicted values in patients with extensive emphysematous areas (<-910 Hounsfield units), but not in patients with chronic obstructive pulmonary disease. Quantitative CT yielded accurate prediction of functional reserve after lung cancer surgery and helped to identify patients whose functional reserves are likely to be underestimated. Hence, this modality should be utilized for patients with marginal pulmonary function.

External ultrasonography of the neck does not add diagnostic value to integrated positron emission tomography-computed tomography (PET-CT) scanning in the diagnosis of cervical lymph node metastases in patients with esophageal carcinoma.

PubMed

Blom, R L G M; Vliegen, R F A; Schreurs, W M J; Belgers, H J; Stohr, I; Oostenbrug, L E; Sosef, M N

2012-08-01

One of the objectives of preoperative imaging in esophageal cancer patients is the detection of cervical lymph node metastases. Traditionally, external ultrasonography of the neck has been combined with computed tomography (CT) in order to improve the detection of cervical metastases. In general, integrated positron emission tomography-computed tomography (PET-CT) has been shown to be superior to CT or PET regarding staging and therefore may limit the role of external ultrasonography of the neck. The objective of this study was to determine the additional value of external ultrasonography of the neck to PET-CT. This study included all patients referred our center for treatment of esophageal carcinoma. Diagnostic staging was performed to determine treatment plan. Cervical lymph nodes were evaluated by external ultrasonography of the neck and PET-CT. In case of suspect lymph nodes on external ultrasonography or PET-CT, fine needle aspiration (FNA) was performed. Between 2008 and 2010, 170 out of 195 referred patients underwent both external ultrasonography of the neck and PET-CT. Of all patients, 84% were diagnosed with a tumor at or below the distal esophagus. In 140 of 170 patients, the cervical region was not suspect; no FNA was performed. Seven out of 170 patients had suspect nodes on both PET-CT and external ultrasonography. Five out of seven patients had cytologically confirmed malignant lymph nodes, one of seven had benign nodes, in one patient FNA was not performed; exclusion from esophagectomy was based on intra-abdominal metastases. In one out of 170 patients, PET-CT showed suspect nodes combined with a negative external ultrasonography; cytology of these nodes was benign. Twenty-two out of 170 patients had a negative PET-CT with suspect nodes on external ultrasonography. In 18 of 22 patients, cervical lymph nodes were cytologically confirmed benign; in four patients, FNA was not possible or inconclusive. At a median postoperative follow-up of 15 months, only 1% of patients developed cervical lymph node metastases. This study shows no additional value of external ultrasonography to a negative PET-CT. According to our results, it can be omitted in the primary workup. However, suspect lymph nodes on PET-CT should be confirmed by FNA to exclude false positives if it would change treatment plan. © 2011 Copyright the Authors. Journal compilation © 2011, Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

Added Value of Coronal Reformations for Duty Radiologists and for Referring Physicians or Surgeons in the CT Diagnosis of Acute Appendicitis

PubMed Central

Lee, Kyoung Ho; Hahn, Seokyung; Lee, Kyung Won; Lee, Hak Jong; Kim, Tae Jung; Kang, Sung-Bum; Shin, Joong Ho; Park, Byung Joo

2006-01-01

Objective To assess the added value of coronal reformation for radiologists and for referring physicians or surgeons in the CT diagnosis of acute appendicitis. Materials and Methods Contrast-enhanced CT was performed using 16-detector-row scanners in 110 patients, 46 of whom had appendicitis. Transverse (5-mm thickness, 4-mm increment), coronal (5-mm thickness, 4-mm increment), and combined transverse and coronal sections were interpreted by four radiologists, two surgeons and two emergency physicians. The area under the receiver operating characteristic curve (Az value), sensitivity, specificity (McNemar test), diagnostic confidence and appendiceal visualization (Wilcoxon signed rank test) were compared. Results For radiologists, the additional coronal sections tended to increase the Az value (0.972 vs. 0.986, p = 0.076) and pooled sensitivity (92% [95% CI: 88, 96] vs. 96% [93, 99]), and enhanced appendiceal visualization in true-positive cases (p = 0.031). For non-radiologists, no such enhancement was observed, and the confidence for excluding acute appendicitis declined (p = 0.013). Coronal sections alone were inferior to transverse sections for diagnostic confidence as well as appendiceal visualization for each reader group studied (p < 0.05). Conclusion The added value of coronal reformation is more apparent for radiologists compared to referring physicians or surgeons in the CT diagnosis of acute appendicitis. PMID:16799269

Intramammary Findings on CT of the Chest – a Review of Normal Anatomy and Possible Findings

PubMed Central

Gossner, Johannes

2016-01-01

Summary Computed tomography (CT) is a frequently performed examination in women of all ages. In all thoracic CT examinations of the chest at least parts of the breasts are included. Therefore incidental breast pathology may be observed. It has been suggested that one out of 250 women undergoing chest CT will show a malignant incidental breast lesion. Given the high number of performed chest CT examinations, this contributes to a significant number of malignancies. In this review, after a brief discussion of the value of computed tomography in breast imaging, normal and pathologic findings are discussed to create awareness of this potential “black box” on chest CT. PMID:28058068

Retrospective review of positron emission tomography with contrast-enhanced computed tomography in the posttreatment setting in human papillomavirus-associated oropharyngeal carcinoma.

PubMed

Chan, Jason Y K; Sanguineti, Giuseppe; Richmon, Jeremy D; Marur, Shanthi; Gourin, Christine G; Koch, Wayne; Chung, Christine H; Quon, Harry; Bishop, Justin A; Aygun, Nafi; Agrawal, Nishant

2012-11-01

To determine the value of positron emission tomography (PET) with contrast-enhanced computed tomography (CT) in assessing the need for neck dissection by retrospectively reviewing the pathology reports of patients with human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (SCC). Retrospective cohort study. Tertiary medical center. Seventy-seven patients with HPV-related SCC. Seventy-seven consecutive patients with a diagnosis of HPV-related SCC who were treated with radiotherapy as the primary treatment between August 2007 and October 2010 were retrospectively evaluated for radiologic and pathologic rate of persistence of nodal metastasis after completion of definitive radiotherapy. Pretreatment and posttreatment imaging included contrast-enhanced CT and PET. Response to treatment was measured on CT, PET at standardized uptake value (SUV) thresholds of 2 and 2.5, and PET/CT by a neuroradiologist in a blinded fashion. Then, the pathology report of the patients who underwent neck dissections was reviewed for nodal status after resection and correlated with the imaging findings. Of the 77 patients, 67 met the study criteria, with an average follow-up PET/CT scan at 90.5 days after completion of radiotherapy. Ten patients did not undergo follow-up PET/CT imaging. Twenty patients underwent neck dissections after completion of radiation therapy. Of these 20 patients, 4 had persistent tumor and 16 did not have viable tumor. Using the final pathology report to correlate with imaging responses, CT had a negative predictive value (NPV) of 85.7% (95% CI, 48.7%-97.4%), PET with SUV thresholds of 2 had an NPV of 91.7% (95% CI, 64.6%-98.5%), PET with a cutoff SUV of 2.5 had an NPV of 85.7% (95% CI, 60.1%-96.0%), PET/CT with an SUV of 2 had an NPV of 100% (95% CI, 59.8%-100.0%), and PET/CT with an SUV of 2.5 had an NPV of 85.7% (95% CI, 48.7%-97.4%). The 47 patients who did not undergo neck dissection had a median follow-up of 26 months without an isolated neck failure. Analysis of all 67 patients in the cohort revealed the following values: CT had an NPV of 95.7% (95% CI, 85.8%-98.8%), PET with an SUV of 2 had an NPV of 98.2% (95% CI, 90.4%-99.7%), PET with an SUV of 2.5 had an NPV of 95.0% (95% CI, 86.3%-98.3%), PET/CT with an SUV of 2 had an NPV of 100.0% (95% CI, 92.0%-100.0%), and PET/CT with an SUV of 2.5 had an NPV of 95.7% (95% CI, 85.8%-98.8%). Positron emission tomography combined with contrast-enhanced CT has a better NPV than either imaging modality alone in patients with HPV-associated oropharyngeal SCC. Furthermore, PET/CT with an SUV threshold of 2 used in patients with HPV-related SCC offers an imaging modality with a high NPV that may obviate the need for unnecessary neck dissections.

Sulfur Biogeochemistry of an Oil Sands Composite Tailings Deposit

PubMed Central

Warren, Lesley A.; Kendra, Kathryn E.; Brady, Allyson L.; Slater, Greg F.

2016-01-01

Composite tailings (CT), an engineered, alkaline, saline mixture of oil sands tailings (FFT), processed sand and gypsum (CaSO4; 1 kg CaSO4 per m3 FFT) are used as a dry reclamation strategy in the Alberta Oil Sands Region (AOSR). It is estimated that 9.6 × 108 m3 of CT are either in, or awaiting emplacement in surface pits within the AOSR, highlighting their potential global importance in sulfur cycling. Here, in the first CT sulfur biogeochemistry investigation, integrated geochemical, pyrosequencing and lipid analyses identified high aqueous concentrations of ∑H2S (>300 μM) and highly altered sulfur compounds composition; low cell biomass (3.3 × 106– 6.0 × 106 cells g−1) and modest bacterial diversity (H' range between 1.4 and 1.9) across 5 depths spanning 34 m of an in situ CT deposit. Pyrosequence results identified a total of 29,719 bacterial 16S rRNA gene sequences, representing 131 OTUs spanning19 phyla including 7 candidate divisions, not reported in oil sands tailings pond studies to date. Legacy FFT common phyla, notably, gamma and beta Proteobacteria, Firmicutes, Actinobacteria, and Chloroflexi were represented. However, overall CT microbial diversity and PLFA values were low relative to other contexts. The identified known sulfate/sulfur reducing bacteria constituted at most 2% of the abundance; however, over 90% of the 131 OTUs identified are capable of sulfur metabolism. While PCR biases caution against overinterpretation of pyrosequence surveys, bacterial sequence results identified here, align with phospholipid fatty acid (PLFA) and geochemical results. The highest bacterial diversities were associated with the depth of highest porewater [∑H2S] (22–24 m) and joint porewater co-occurrence of Fe2+ and ∑H2S (6–8 m). Three distinct bacterial community structure depths corresponded to CT porewater regions of (1) shallow evident Fe(II) (<6 m), (2) co-occurring Fe(II) and ∑H2S (6–8 m) and (3) extensive ∑H2S (6–34 m) (UniFrac). Candidate divisions GNO2, NKB19 and Spam were present only at 6–8 m associated with co-occurring [Fe(II)] and [∑H2S]. Collectively, results indicate that CT materials are differentiated from other sulfur rich environments by modestly diverse, low abundance, but highly sulfur active and more enigmatic communities (7 candidate divisions present within the 19 phyla identified). PMID:26869997

[Value of quantitative iodine-based material decomposition images with gemstone spectral CT imaging in the follow-up of patients with hepatocellular carcinoma after TACE treatment].

PubMed

Xing, Gusheng; Wang, Shuang; Li, Chenrui; Zhao, Xinming; Zhou, Chunwu

2015-03-01

To investigate the value of quantitative iodine-based material decomposition images with gemstone spectral CT imaging in the follow-up of patients with hepatocellular carcinoma (HCC) after transcatheter arterial chemoebolization (TACE). Consecutive 32 HCC patients with previous TACE treatment were included in this study. For the follow-up, arterial phase (AP) and venous phase (VP) dual-phase CT scans were performed with a single-source dual-energy CT scanner (Discovery CT 750HD, GE Healthcare). Iodine concentrations were derived from iodine-based material-decomposition images in the liver parenchyma, tumors and coagulation necrosis (CN) areas. The iodine concentration difference (ICD) between the arterial-phase (AP) and venal-phase (VP) were quantitatively evaluated in different tissues.The lesion-to-normal parenchyma iodine concentration ratio (LNR) was calculated. ROC analysis was performed for the qualitative evaluation, and the area under ROC (Az) was calculated to represent the diagnostic ability of ICD and LNR. In all the 32 HCC patients, the region of interesting (ROI) for iodine concentrations included liver parenchyma (n=42), tumors (n=28) and coagulation necrosis (n=24). During the AP the iodine concentration of CNs (median value 0.088 µg/mm(3)) appeared significantly higher than that of the tumors (0.064 µg/mm(3), P=0.022) and liver parenchyma (0.048 µg/mm(3), P=0.005). But it showed no significant difference between liver parenchyma and tumors (P=0.454). During the VP the iodine concentration in hepatic parenchyma (median value 0.181 µg/mm(3)) was significantly higher than that in CNs (0.140 µg/mm(3), P=0.042). There was no significant difference between liver parenchyma and tumors, CNs and tumors (both P>0.05). The median value of ICD in CNs was 0.006 µg/mm(3), significantly lower than that of the HCC (0.201 µg/mm(3), P<0.001) and hepatic parenchyma (0.117 µg/mm(3), P<0.001). The ICDs in tumors and hepatic parenchyma showed no significant difference (P=0.829). During the AP, the LNR had no significant difference between CNs and tumors (a median value 1.805 vs. 1.310, P=0.389), and during the VP, the difference was also non-significant (the median value 0.647 vs. 0.713, P=0.660). The mean Az value of ICDs for evaluation of surviving tumor tissues was 0.804, whiles LNR measured a disappointing result in both AV images and VP images. Quantitative iodine-based material decomposition images with gemstone spectral CT imaging can improve the diagnostic efficacy of CT imaging for HCC patients after TACE treatment.

Identification of yellow-pigmented bacteria isolated from hospital tap water in Japan and their chlorine resistance.

PubMed

Furuhata, Katsunori; Kato, Yuko; Goto, Keiichi; Saitou, Keiko; Sugiyama, Jun-Ichi; Hara, Motonobu; Fukuyama, Masahumi

2007-06-01

Twenty-five yellow chromogenic strains isolated from hospital tap water samples collected nationwide were identified by partial 16S rDNA sequencing. In addition, the chlorine resistance of the isolates was experimentally investigated. The results showed that of the strains tested, 12 strains (48.0%) were Sphingomonas ursincola/natatoria, which was most frequently identified, followed by 2 strains (8.0%) of Mycobacterium frederiksbergense and 1 strain (4.0%) each of Sphingomonas adhaesiva, Sphingopyxis witflariensis and Porphyrobacter donghaensis. The other strains were not identified clearly but they belonged to the order of Alphaproteobacteria. On the other hand, the identification results by sequencing and biochemical property testing were not consistent in any of the strains, showing that it was difficult to accurately identify the yellow chromogenic bacteria in tap water based on only their biochemical properties. When the 25 isolates were exposed to 0.1 mg/l residual free chlorine for 1 minute, 22 isolates (88.0%) survived. When the CT (Concentration Time) value killing 99.99% of the bacteria was investigated in 6 of these survivors, M. frederiksbergense (Y-1 strain) was most resistant to chlorine with the CT value of 32 mg x min/l, followed by S. ursincola/natatoria (Y-7 strain) with the CT value of 3.3 mg x min/l. The CT values of Y-5 (Sphingomonas sp.), Y-27 (S. ursincola/natatoria) and Y-21 (Asticacaulis sp.) were within the range of 0.9-0.1 mg x min /l. Of the 6 strains, S. adhaesiva (Y-10) showed the weakest resistance with the CT value of 0.03 mg x min/l. It was clarified that most yellow chromogenic bacteria isolated from hospital tap water were Sphingomonas spp., and these bacteria were experimentally resistant to chlorine.

Factors influencing inactivation of Klebsiella pneumoniae by chlorine and chloramine.

PubMed

Goel, Sudha; Bouwer, Edward J

2004-01-01

Inactivation of Klebsiella pneumoniae cultures by chlorine and chloramine was evaluated under different growth conditions by varying nutrient media dilution, concentrations of essential inorganic nutrients (FeCl3, MgSO4, phosphate, and ammonium salts), and temperature. All inactivation assays were performed at room temperature (22-23 degrees C) and near neutral pH (7.2-7.5). C*T(99.9) values for chlorine increased >20-fold and for chloramine increased 2.6-fold when cells were grown in 100-fold diluted nutrient broth (2NB) solutions (final TOC of 35-40 mg/L). Background levels of Mg: 6.75 x 10(-2) mM and Fe: 3.58 x 10(-5) mM or high levels of FeCl3 (0.01 mM) and MgSO4 (1 mM) during growth resulted in the highest resistances to chlorine with C*T(99.9) values of 13.06 (+/-0.91) and 13.78 (+/-1.97) mg-min/L, respectively. Addition of low levels of FeCl3 (0.001 mM) and MgSO4 (0.1 mM) to K. pneumoniae cultures during growth resulted in the lowest bacterial resistances to inactivation; C*T(99.9) values ranged from 0.28 (+/-0.06) to 1.88 (+/-0.53)mg-min/L in these cultures. Increase in growth temperature from 22.5 degrees C to 35 degrees C for unamended 2NB cultures resulted in a 42-fold decrease in C*T(99.9) values for chlorine. A similar change in temperature resulted in no significant change in C*T(99.9) values for chloramine. These results indicate that inactivation of K. pneumoniae cultures by chlorine was highly sensitive to changes in growth conditions unlike inactivation by chloramine.

Influence of CT automatic tube current modulation on uncertainty in effective dose.

PubMed

Sookpeng, S; Martin, C J; Gentle, D J

2016-01-01

Computed tomography (CT) scanners are equipped with automatic tube current modulation (ATCM) systems that adjust the current to compensate for variations in patient attenuation. CT dosimetry variables are not defined for ATCM situations and, thus, only the averaged values are displayed and analysed. The patient effective dose (E), which is derived from a weighted sum of organ equivalent doses, will be modified by the ATCM. Values for E for chest-abdomen-pelvis CT scans have been calculated using the ImPACT spreadsheet for patients on five CT scanners. Values for E resulting from the z-axis modulation under ATCM have been compared with results assessed using the same effective mAs values with constant tube currents. Mean values for E under ATCM were within ±10 % of those for fixed tube currents for all scanners. Cumulative dose distributions under ATCM have been simulated for two patient scans using single-slice dose profiles measured in elliptical and cylindrical phantoms on one scanner. Contributions to the effective dose from organs in the upper thorax under ATCM are 30-35 % lower for superficial tissues (e.g. breast) and 15-20 % lower for deeper organs (e.g. lungs). The effect on doses to organs in the abdomen depends on body shape, and they can be 10-22 % higher for larger patients. Results indicate that scan dosimetry parameters, dose-length product and effective mAs averaged over the whole scan can provide an assessment in terms of E that is sufficiently accurate to quantify relative risk for routine patient exposures under ATCM. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Intra- and Interobserver Variability of Cochlear Length Measurements in Clinical CT.

PubMed

Iyaniwura, John E; Elfarnawany, Mai; Riyahi-Alam, Sadegh; Sharma, Manas; Kassam, Zahra; Bureau, Yves; Parnes, Lorne S; Ladak, Hanif M; Agrawal, Sumit K

2017-07-01

The cochlear A-value measurement exhibits significant inter- and intraobserver variability, and its accuracy is dependent on the visualization method in clinical computed tomography (CT) images of the cochlea. An accurate estimate of the cochlear duct length (CDL) can be used to determine electrode choice, and frequency map the cochlea based on the Greenwood equation. Studies have described estimating the CDL using a single A-value measurement, however the observer variability has not been assessed. Clinical and micro-CT images of 20 cadaveric cochleae were acquired. Four specialists measured A-values on clinical CT images using both standard views and multiplanar reconstructed (MPR) views. Measurements were repeated to assess for intraobserver variability. Observer variabilities were evaluated using intra-class correlation and absolute differences. Accuracy was evaluated by comparison to the gold standard micro-CT images of the same specimens. Interobserver variability was good (average absolute difference: 0.77 ± 0.42 mm) using standard views and fair (average absolute difference: 0.90 ± 0.31 mm) using MPR views. Intraobserver variability had an average absolute difference of 0.31 ± 0.09 mm for the standard views and 0.38 ± 0.17 mm for the MPR views. MPR view measurements were more accurate than standard views, with average relative errors of 9.5 and 14.5%, respectively. There was significant observer variability in A-value measurements using both the standard and MPR views. Creating the MPR views increased variability between experts, however MPR views yielded more accurate results. Automated A-value measurement algorithms may help to reduce variability and increase accuracy in the future.

[Correlation of intracranial pressure and diameter of the sheath of the optic nerve by computed tomography in severe traumatic brain injury].

PubMed

Turkin, A M; Oshorov, A V; Pogosbekyan, E L; Smirnov, A S; Dmitrieva, A S

Noninvasive techniques to evaluate intracranial pressure (ICP) are important for everyday practice in intensive care and neurosurgery departments. CT data can be used to evaluate the optic nerve sheath diameter (ONSD) and, indirectly, the ICP value. The ONSD value is an additional criterion in deciding on invasive monitoring of ICP. To analyze a correlation between CT-based ONSD and the results of invasive measurements of ICP in patients with severe traumatic brain injury. The study evaluated 41 patients with severe traumatic brain injury within the first 48 h after injury. Invasive monitoring of ICP (Codman & Shurtlett, MA, USA) was performed during 7±1.7 days. ONSD was measured using axial CT scans (CereTom, Neurologica Danvers, MA, USA) with a slice thickness of 2.5 mm. The ONSD value was measured at a distance of 3 mm from the posterior eyeball contour. The patients were allocated in a group with normal ICP (10 patients) and a group with high ICP (31 patients). ONSD served as an ICP classifier. The data were processed using ROC analysis. According to the CT data, the optimal threshold ONSD value was 6.35 mm in patients in the acute TBI period. The sensitivity was 0.93 (95% СI 0.84-1.00), the specificity was 0.80 (95% СI 0.50-1.00), and AUC was 0.87 (95% СI 0.69-1.00). We found a correlation between the CT-based ONSD and the median ICP (R=0.32, p<0.05). An ONSD value of 6.35 mm and more is one of the signs of previous or existing ICP.

A breast-specific, negligible-dose scatter correction technique for dedicated cone-beam breast CT: a physics-based approach to improve Hounsfield Unit accuracy

NASA Astrophysics Data System (ADS)

Yang, Kai; Burkett, George, Jr.; Boone, John M.

2014-11-01

The purpose of this research was to develop a method to correct the cupping artifact caused from x-ray scattering and to achieve consistent Hounsfield Unit (HU) values of breast tissues for a dedicated breast CT (bCT) system. The use of a beam passing array (BPA) composed of parallel-holes has been previously proposed for scatter correction in various imaging applications. In this study, we first verified the efficacy and accuracy using BPA to measure the scatter signal on a cone-beam bCT system. A systematic scatter correction approach was then developed by modeling the scatter-to-primary ratio (SPR) in projection images acquired with and without BPA. To quantitatively evaluate the improved accuracy of HU values, different breast tissue-equivalent phantoms were scanned and radially averaged HU profiles through reconstructed planes were evaluated. The dependency of the correction method on object size and number of projections was studied. A simplified application of the proposed method on five clinical patient scans was performed to demonstrate efficacy. For the typical 10-18 cm breast diameters seen in the bCT application, the proposed method can effectively correct for the cupping artifact and reduce the variation of HU values of breast equivalent material from 150 to 40 HU. The measured HU values of 100% glandular tissue, 50/50 glandular/adipose tissue, and 100% adipose tissue were approximately 46, -35, and -94, respectively. It was found that only six BPA projections were necessary to accurately implement this method, and the additional dose requirement is less than 1% of the exam dose. The proposed method can effectively correct for the cupping artifact caused from x-ray scattering and retain consistent HU values of breast tissues.

Hydraulic fracture development in granite during cyclic injection

NASA Astrophysics Data System (ADS)

Diaz, M.; Jung, S. G.; Nam, Y. J.; Yeom, S.; Zhuang, L.; Kim, K. Y.

2017-12-01

The concept of fatigue hydraulic fracturing was introduced by Zang et al. (2013) as an alternative stimulation scheme to mitigate seismicity during hydraulic stimulation. In situ experiments in hard rock, and laboratory tests in granite have shown a decrease in breakdown pressure during cyclic injection. However, little work has been done in relation to the study of fracture evolution with increasing number of injection cycles. This study uses cylindrical granite specimens to observe induced fractures under continuous injection and fracture development during cyclic injection, aided by X-ray CT technology and AE monitoring. The rock specimens have 30 mm in diameter, 48 mm in height, and a 5 mm diameter central borehole drilled along its axis. Each specimen was axially loaded with 10 MPa, and without confining pressure. The first specimen was continuously injected with water at a rate of 50 mm3/s. For the second specimen, the same injection rate was used, but it was stopped multiple times when the pressure reached a value of 4 MPa in order to create cycles. The time during each injection peak was 2 min. The results show how induced fractures are likely to initiate at the borehole wall and between grain mineral boundaries. Also, the fractures increase true length and height with increasing number of cycles, and mineral distribution affected fracture orientation during its development. These observations could shed light into the physics involved behind this process

Multi-national findings on radiation protection of children.

PubMed

Rehani, Madan M

2014-10-01

This article reviews issues of radiation protection in children in 52 low-resource countries. Extensive information was obtained through a survey by the International Atomic Energy Agency (IAEA); wide-ranging information was available from 40 countries and data from the other countries pertained to frequency of pediatric CT examinations. Of note is that multi-detector CT (MDCT) was available in 77% of responses to the survey, typically nodal centers in these countries. Nearly 75% of these scanners were reported to have dose displays. The pediatric CT usage was lower in European facilities as compared to Asian and African facilities, where usage was twice as high. The most frequently scanned body part was the head. Frequent use of 120 kVp was reported in children. The ratio of maximum to minimum CT dose index volume (CTDIvol) values varied between 15 for abdomen CT in the age group 5-10 years and 100 for chest CT in the age group <1 year. In 8% of the CT systems, CTDI values for pediatric patients were higher than those for adults in at least one age group and for one type of examination. Use of adult protocols for children was associated with CTDIw or CTDIvol values in children that were double those of adults for head and chest examination and 50% higher for abdomen examination. Patient dose records were kept in nearly half of the facilities, with the highest frequency in Europe (55% of participating facilities), and in 49% of Asian, 36% of Latin American and 14% of African facilities. The analysis of the first-choice examinations in seven clinical conditions showed that practice was in accordance with guidelines for only three of seven specified clinical conditions.

Coronary artery calcium: a multi-institutional, multimanufacturer international standard for quantification at cardiac CT.

PubMed

McCollough, Cynthia H; Ulzheimer, Stefan; Halliburton, Sandra S; Shanneik, Kaiss; White, Richard D; Kalender, Willi A

2007-05-01

To develop a consensus standard for quantification of coronary artery calcium (CAC). A standard for CAC quantification was developed by a multi-institutional, multimanufacturer international consortium of cardiac radiologists, medical physicists, and industry representatives. This report specifically describes the standardization of scan acquisition and reconstruction parameters, the use of patient size-specific tube current values to achieve a prescribed image noise, and the use of the calcium mass score to eliminate scanner- and patient size-based variations. An anthropomorphic phantom containing calibration inserts and additional phantom rings were used to simulate small, medium-size, and large patients. The three phantoms were scanned by using the recommended protocols for various computed tomography (CT) systems to determine the calibration factors that relate measured CT numbers to calcium hydroxyapatite density and to determine the tube current values that yield comparable noise values. Calculation of the calcium mass score was standardized, and the variance in Agatston, volume, and mass scores was compared among CT systems. Use of the recommended scanning parameters resulted in similar noise for small, medium-size, and large phantoms with all multi-detector row CT scanners. Volume scores had greater interscanner variance than did Agatston and calcium mass scores. Use of a fixed calcium hydroxyapatite density threshold (100 mg/cm(3)), as compared with use of a fixed CT number threshold (130 HU), reduced interscanner variability in Agatston and calcium mass scores. With use of a density segmentation threshold, the calcium mass score had the smallest variance as a function of patient size. Standardized quantification of CAC yielded comparable image noise, spatial resolution, and mass scores among different patient sizes and different CT systems and facilitated reduced radiation dose for small and medium-size patients.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, Carryn M., E-mail: carryn-anderson@uiowa.edu; Chang, Tangel; Graham, Michael M.

Purpose: To evaluate dynamic [{sup 18}F]-fluorodeoxyglucose (FDG) uptake methodology as a post–radiation therapy (RT) response assessment tool, potentially enabling accurate tumor and therapy-related inflammation differentiation, improving the posttherapy value of FDG–positron emission tomography/computed tomography (FDG-PET/CT). Methods and Materials: We prospectively enrolled head-and-neck squamous cell carcinoma patients who completed RT, with scheduled 3-month post-RT FDG-PET/CT. Patients underwent our standard whole-body PET/CT scan at 90 minutes, with the addition of head-and-neck PET/CT scans at 60 and 120 minutes. Maximum standardized uptake values (SUV{sub max}) of regions of interest were measured at 60, 90, and 120 minutes. The SUV{sub max} slope between 60 and 120 minutes and changemore » of SUV{sub max} slope before and after 90 minutes were calculated. Data were analyzed by primary site and nodal site disease status using the Cox regression model and Wilcoxon rank sum test. Outcomes were based on pathologic and clinical follow-up. Results: A total of 84 patients were enrolled, with 79 primary and 43 nodal evaluable sites. Twenty-eight sites were interpreted as positive or equivocal (18 primary, 8 nodal, 2 distant) on 3-month 90-minute FDG-PET/CT. Median follow-up was 13.3 months. All measured SUV endpoints predicted recurrence. Change of SUV{sub max} slope after 90 minutes more accurately identified nonrecurrence in positive or equivocal sites than our current standard of SUV{sub max} ≥2.5 (P=.02). Conclusions: The positive predictive value of post-RT FDG-PET/CT may significantly improve using novel second derivative analysis of dynamic triphasic FDG-PET/CT SUV{sub max} slope, accurately distinguishing tumor from inflammation on positive and equivocal scans.« less

Volumetric quantification of bone-implant contact using micro-computed tomography analysis based on region-based segmentation.

PubMed

Kang, Sung-Won; Lee, Woo-Jin; Choi, Soon-Chul; Lee, Sam-Sun; Heo, Min-Suk; Huh, Kyung-Hoe; Kim, Tae-Il; Yi, Won-Jin

2015-03-01

We have developed a new method of segmenting the areas of absorbable implants and bone using region-based segmentation of micro-computed tomography (micro-CT) images, which allowed us to quantify volumetric bone-implant contact (VBIC) and volumetric absorption (VA). The simple threshold technique generally used in micro-CT analysis cannot be used to segment the areas of absorbable implants and bone. Instead, a region-based segmentation method, a region-labeling method, and subsequent morphological operations were successively applied to micro-CT images. The three-dimensional VBIC and VA of the absorbable implant were then calculated over the entire volume of the implant. Two-dimensional (2D) bone-implant contact (BIC) and bone area (BA) were also measured based on the conventional histomorphometric method. VA and VBIC increased significantly with as the healing period increased (p<0.05). VBIC values were significantly correlated with VA values (p<0.05) and with 2D BIC values (p<0.05). It is possible to quantify VBIC and VA for absorbable implants using micro-CT analysis using a region-based segmentation method.

Imaging of prostate cancer with PET/CT using 18F-Fluorocholine

PubMed Central

Vali, Reza; Loidl, Wolfgang; Pirich, Christian; Langesteger, Werner; Beheshti, Mohsen

2015-01-01

While 18F-Fluorodeoxyglucose (18F-FDG) Positron-Emission Tomography (PET) has limited value in prostate cancer (PCa), it may be useful for specific subgroups of PCa patients with hormone-resistant poorly differentiated cell types. 18F-Fluorocholine (18F-FCH) PET/CT has been increasingly used in primary and recurrent PCa and has been shown to add valuable information. Although there is a correlation between the foci of activity and the areas of malignancy in the prostate gland, the clinical value of 18F-FCH is still controversial for detection of the malignant focus in the prostate. For the T-staging of PCa at diagnosis the value of 18F-FCH is limited. This is probably due to limited resolution of PET system and positive findings in benign prostate diseases. Conversely, 18F-FCH PET/CT is a promising imaging modality for the delineation of local and distant nodal recurrence and bone metastases and is poised to have an impact on therapy management. In this review, recent studies of 18F-FCH PET/CT in PCa are summarized. PMID:25973332

Longitudinal perceptions of the side effects of chemotherapy in patients with gynecological cancer.

PubMed

Hsu, Hui-Chun; Tsai, Su-Yu; Wu, Shang-Liang; Jeang, Shiow-Roug; Ho, Mei-Yao; Liou, Wen-Shiung; Chiang, An-Jen; Chang, Tsung-Hsien

2017-11-01

This study aimed to assess the incidence and difference of side effects among six courses of chemotherapy (C/T) in gynecological cancer patients. The study period was from Sep. 2010 to Dec. 2011 at the Kaohsiung Veterans General Hospital in Taiwan. The treating protocols, courses, and drugs of C/T in patient were considered according to the different malignant cancers and clinical conditions. The patient data of age, marriage status, education, religion, and experiences of C/T were collected. The patients' or their families' reported side effects of C/T were recorded daily from the beginning of C/T to the 10th day after C/T in each cycle and every course of C/T. Total 89 patients enrolled into the study received total 450 courses of C/T. The mean age was 54.52 ± 11.02. Ovarian cancer was the most common malignant disease (64.0%). The most often combination of drugs used was Taxol and carboplatin (40.9%). Patients complained peripheral numbness of limbs, with the highest incidence of 58.6%. The side effects with incidence about 50% were decreased fatigue (55.0%) and hair loss (49.9%). Other side effects with different levels of incidence were also noticed, such as lack of appetite, changes in taste, and muscle ache. The incidences of peripheral limb numbness and hair loss were increased with following courses of C/T. The high incidence of fatigue did not show variation between different courses of C/T. This study revealed the incidence of side effects and occurrence timing during C/T in patients with gynecological cancer. These data provide substantial information to patients and their families to understand the potential side effects of C/T courses, which might increase their compliance in receiving adjuvant C/T. Relieving the side effects in C/T would be important to improve their quality of daily life and treatment willingness.