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Sample records for ct head-to-head comparison

  1. Head-to-Head Comparison of Anti-Inflammatory Performance of Known Natural Products In Vitro

    PubMed Central

    Allijn, Iris E.; Vaessen, Stefan F. C.; Quarles van Ufford, Linda C.; Beukelman, Kees J.; de Winther, Menno P. J.; Storm, Gert; Schiffelers, Raymond M.

    2016-01-01

    Inflammation is an important therapeutic target. Due to their potency, steroidal drugs dominate the current treatment of inflammatory disorders. However, steroidal drugs can also exert a broad range of side effects and appear not always effective. This calls for the development of alternative drugs with a different mechanism of action, which are likely to be found in the field of natural products (NPs). For many NPs strong anti-inflammatory effects have been described, but usually investigating a single compound in a single assay. In this study, eight promising NPs were selected and tested against the strong anti-inflammatory drug prednisolone. For this head-to-head comparison, in vitro assays were used which represent different pathways of the inflammatory response: TNF-α and IL-6 expression by macrophages, IL-8 expression by colon epithelial cells, ROS production in polymorphonuclear leukocytes and platelet activation in whole blood. Performance profiles were established which allowed us to identify curcumin, berberine chloride and epigallocatechin gallate as potential alternatives for prednisolone or other glucocorticoids in inflammation. PMID:27163931

  2. Head-to-head comparisons of hydrochlorothiazide with indapamide and chlorthalidone: antihypertensive and metabolic effects.

    PubMed

    Roush, George C; Ernst, Michael E; Kostis, John B; Tandon, Suraj; Sica, Domenic A

    2015-05-01

    Hydrochlorothiazide (HCTZ) has often been contrasted with chlorthalidone, but relatively little is known about HCTZ versus indapamide (INDAP). This systematic review retrieved 9765 publications, and from these, it identified 14 randomized trials with 883 patients comparing HCTZ with INDAP and chlorthalidone on antihypertensive potency or metabolic effects. To make fair comparisons, the dose of the diuretic in each arm was assigned 1 of 3 dose levels. In random effects meta-analysis, INDAP and chlorthalidone lowered systolic blood pressure more than HCTZ: -5.1 mm Hg (95% confidence interval, -8.7 to -1.6); P=0.004 and -3.6 mm Hg (95% confidence interval, -7.3 to 0.0); P=0.052, respectively. For both comparisons, there was minimal heterogeneity in effect across trials and no evidence for publication bias. The HCTZ-INDAP contrast was biased in favor of greater HCTZ potency because of a much greater contribution to the overall effect from trials in which the HCTZ arm had a higher dose level than the INDAP arm. For the HCTZ-INDAP comparison, no single trial was responsible for the overall result nor was it possible to detect significant modifications of this comparison by duration of follow-up, high- versus low-bias trials, or the presence or absence of background medications. There were no detectable differences between HCTZ and INDAP in metabolic adverse effects, including effects on serum potassium. In conclusion, these head-to-head comparisons demonstrate that, like chlorthalidone, INDAP is more potent than HCTZ at commonly prescribed doses without evidence for greater adverse metabolic effects.

  3. A Head-to-head Comparison between SurgiMend and Epiflex in 127 Breast Reconstructions

    PubMed Central

    Vogt, Nadine; Brunnert, Klaus; Sauerwald, Axel; Puppe, Julian; Warm, Mathias

    2015-01-01

    Background: The use of acellular dermal matrices (ADM) has become a widely used option in breast reconstruction. A great deal of literature is available, totaling over 2400 ADM reconstructions. Nonetheless, head-to-head comparisons between SurgiMend and Epiflex are not yet reported. In fact, this is the first clinical data report on the use of Epiflex. This work will, therefore, compare postoperative complication rates and costs for these ADMs. Methods: This analysis is a retrospective review of a single surgeon’s 6-year experience with both SurgiMend—an acellular bovine dermal collagen matrix for soft-tissue reconstruction and Epiflex—a decellularized human skin tissue from 2008 to 2013. Results: One hundred patients had a total of 127 implant-based reconstructions using SurgiMend (64 cases; 50.4%) or Epiflex (63 cases; 49.6%). Gross complication rates were 11.1% for SurgiMend and 40.6% for Epiflex including hematoma, postoperative skin irritation, infection, necrosis, and revision surgery. The most common complication was postoperative red breast syndrome. Severe complications requiring revision surgery were significantly increased in patients treated with Epiflex (12.5%) compared with SurgiMend (4.8%). Conclusions: This retrospective analysis favors the use of SurgiMend over Epiflex because of significantly lower gross complication rates. Severe complication rates are comparable with those reported in literature for both products. Although results promote the use of SurgiMend, the single surgeon retrospective nature of this work limits its clinical impact. PMID:26180740

  4. Head-to-Head Comparison of Transcranial Random Noise Stimulation, Transcranial AC Stimulation, and Transcranial DC Stimulation for Tinnitus

    PubMed Central

    Vanneste, Sven; Fregni, Felipe; De Ridder, Dirk

    2013-01-01

    Tinnitus is the perception of a sound in the absence of an external sound stimulus. This phantom sound has been related to plastic changes and hyperactivity in the auditory cortex. Different neuromodulation techniques such as transcranial magnetic stimulation and transcranial direct current stimulation (tDCS) have been used in an attempt to modify local and distant neuroplasticity as to reduce tinnitus symptoms. Recently, two techniques of pulsed electrical stimulation using weak electrical currents – transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS) – have also shown significant neuromodulatory effects. In the present study we conducted the first head-to-head comparison of three different transcranial electrical stimulation (tES) techniques, namely tDCS, tACS, and tRNS in 111 tinnitus patients by placing the electrodes overlying the auditory cortex bilaterally. The results demonstrated that tRNS induced the larger transient suppressive effect on the tinnitus loudness and the tinnitus related distress as compared to tDCS and tACS. Both tDCS and tACS induced small and non-significant effects on tinnitus symptoms, supporting the superior effects of tRNS as a method for tinnitus suppression. PMID:24391599

  5. Head-To-Head Comparison of Different Solubility-Enabling Formulations of Etoposide and Their Consequent Solubility-Permeability Interplay.

    PubMed

    Beig, Avital; Miller, Jonathan M; Lindley, David; Carr, Robert A; Zocharski, Philip; Agbaria, Riad; Dahan, Arik

    2015-09-01

    The purpose of this study was to conduct a head-to-head comparison of different solubility-enabling formulations, and their consequent solubility-permeability interplay. The low-solubility anticancer drug etoposide was formulated in several strengths of four solubility-enabling formulations: hydroxypropyl-β-cyclodextrin, the cosolvent polyethylene glycol 400 (PEG-400), the surfactant sodium lauryl sulfate, and an amorphous solid dispersion formulation. The ability of these formulations to increase the solubility of etoposide was investigated, followed by permeability studies using the parallel artificial membrane permeability assay (PAMPA) and examination of the consequent solubility-permeability interplay. All formulations significantly increased etoposide's apparent solubility. The cyclodextrin-, surfactant-, and cosolvent-based formulations resulted in a concomitant decreased permeability that could be modeled directly from the proportional increase in the apparent solubility. On the contrary, etoposide permeability remained constant when using the ASD formulation, irrespective of the increased apparent solubility provided by the formulation. In conclusion, supersaturation resulting from the amorphous form overcomes the solubility-permeability tradeoff associated with other formulation techniques. Accounting for the solubility-permeability interplay may allow to develop better solubility-enabling formulations, thereby maximizing the overall absorption of lipophilic orally administered drugs.

  6. Head-to-head comparisons of carbon fiber microelectrode coatings for sensitive and selective neurotransmitter detection by voltammetry.

    PubMed

    Singh, Yogesh S; Sawarynski, Lauren E; Dabiri, Pasha D; Choi, Wonwoo R; Andrews, Anne M

    2011-09-01

    Voltammetry is widely used to investigate neurotransmission and other biological processes but is limited by poor chemical selectivity and fouling of commonly used carbon fiber microelectrodes (CFMs). We performed direct comparisons of three key coating materials purported to impart selectivity and fouling resistance to electrodes: Nafion, base-hydrolyzed cellulose acetate (BCA), and fibronectin. We systematically evaluated the impact on a range of electrode parameters. Fouling due to exposure to brain tissue was investigated using an approach that minimizes the use of animals while enabling evaluation of statistically significant populations of electrodes. We find that BCA is relatively fouling-resistant. Moreover, detection at BCA-coated CFMs can be tuned by altering hydrolysis times to minimize the impact on sensitivity losses while maintaining fouling resistance. Fibronectin coating is associated with moderate losses in sensitivity after coating and fouling. Nafion imparts increased sensitivity for dopamine and norepinephrine but not serotonin, as well as the anticipated selectivity for cationic neurotransmitters over anionic metabolites. Although Nafion has been suggested to resist fouling, both dip-coating and electrodeposition of Nafion are associated with substantial fouling, similar to levels observed at bare electrodes after exposure to brain tissue. Direct comparisons of these coatings identified unique electroanalytical properties of each that can be used to guide selection tailored to the goals and environment of specific studies.

  7. Head-to-Head Comparison of Two Popular Cortical Thickness Extraction Algorithms: A Cross-Sectional and Longitudinal Study

    PubMed Central

    Redolfi, Alberto; Manset, David; Barkhof, Frederik; Wahlund, Lars-Olof; Glatard, Tristan; Mangin, Jean-François; Frisoni, Giovanni B.

    2015-01-01

    Background and Purpose The measurement of cortical shrinkage is a candidate marker of disease progression in Alzheimer’s. This study evaluated the performance of two pipelines: Civet-CLASP (v1.1.9) and Freesurfer (v5.3.0). Methods Images from 185 ADNI1 cases (69 elderly controls (CTR), 37 stable MCI (sMCI), 27 progressive MCI (pMCI), and 52 Alzheimer (AD) patients) scanned at baseline, month 12, and month 24 were processed using the two pipelines and two interconnected e-infrastructures: neuGRID (https://neugrid4you.eu) and VIP (http://vip.creatis.insa-lyon.fr). The vertex-by-vertex cross-algorithm comparison was made possible applying the 3D gradient vector flow (GVF) and closest point search (CPS) techniques. Results The cortical thickness measured with Freesurfer was systematically lower by one third if compared to Civet’s. Cross-sectionally, Freesurfer’s effect size was significantly different in the posterior division of the temporal fusiform cortex. Both pipelines were weakly or mildly correlated with the Mini Mental State Examination score (MMSE) and the hippocampal volumetry. Civet differed significantly from Freesurfer in large frontal, parietal, temporal and occipital regions (p<0.05). In a discriminant analysis with cortical ROIs having effect size larger than 0.8, both pipelines gave no significant differences in area under the curve (AUC). Longitudinally, effect sizes were not significantly different in any of the 28 ROIs tested. Both pipelines weakly correlated with MMSE decay, showing no significant differences. Freesurfer mildly correlated with hippocampal thinning rate and differed in the supramarginal gyrus, temporal gyrus, and in the lateral occipital cortex compared to Civet (p<0.05). In a discriminant analysis with ROIs having effect size larger than 0.6, both pipelines yielded no significant differences in the AUC. Conclusions Civet appears slightly more sensitive to the typical AD atrophic pattern at the MCI stage, but both pipelines

  8. H3N2 Mismatch of 2014-15 Northern Hemisphere Influenza Vaccines and Head-to-head Comparison between Human and Ferret Antisera derived Antigenic Maps

    NASA Astrophysics Data System (ADS)

    Xie, Hang; Wan, Xiu-Feng; Ye, Zhiping; Plant, Ewan P.; Zhao, Yangqing; Xu, Yifei; Li, Xing; Finch, Courtney; Zhao, Nan; Kawano, Toshiaki; Zoueva, Olga; Chiang, Meng-Jung; Jing, Xianghong; Lin, Zhengshi; Zhang, Anding; Zhu, Yanhong

    2015-10-01

    The poor performance of 2014-15 Northern Hemisphere (NH) influenza vaccines was attributed to mismatched H3N2 component with circulating epidemic strains. Using human serum samples collected from 2009-10, 2010-11 and 2014-15 NH influenza vaccine trials, we assessed their cross-reactive hemagglutination inhibition (HAI) antibody responses against recent H3 epidemic isolates. All three populations (children, adults, and older adults) vaccinated with the 2014-15 NH egg- or cell-based vaccine, showed >50% reduction in HAI post-vaccination geometric mean titers against epidemic H3 isolates from those against egg-grown H3 vaccine strain A/Texas/50/2012 (TX/12e). The 2014-15 NH vaccines, regardless of production type, failed to further extend HAI cross-reactivity against H3 epidemic strains from previous seasonal vaccines. Head-to-head comparison between ferret and human antisera derived antigenic maps revealed different antigenic patterns among representative egg- and cell-grown H3 viruses characterized. Molecular modeling indicated that the mutations of epidemic H3 strains were mainly located in antibody-binding sites A and B as compared with TX/12e. To improve vaccine strain selection, human serologic testing on vaccination-induced cross-reactivity need be emphasized along with virus antigenic characterization by ferret model.

  9. A head-to-head hands-on comparison of ERCP mechanical simulator (EMS) and Ex-vivo Porcine Stomach Model (PSM).

    PubMed

    Leung, Joseph W; Wang, Dong; Hu, Bing; Lim, Brian; Leung, Felix W

    2011-07-01

    BACKGROUND: ERCP mechanical simulator (EMS) and ex-vivo porcine stomach model (PSM) have been described. No direct comparison was reported on endoscopists' perception regarding their efficacy for ERCP training OBJECTIVE: Comparative assessment of EMS and PSM. DESIGN: Questionnaire survey before and after practice. SETTING: Hands-on practice workshops. SUBJECTS: 22 endoscopists with prior experience in 111±225 (mean±SD) ERCP. INTERVENTIONS: Participants performed scope insertion, selective bile duct cannulation with guide wire and insertion of a single biliary stent. Simulated fluoroscopy with external pin-hole camera (EMS), or with additional transillumination (PSM) was used to monitor exchange of accessories. MAIN OUTCOME MEASURE: Participants rated their understanding and confidence before and after hands-on practice, and credibility of each simulator for ERCP training. Comparative efficacy of EMS and PSM for ERCP education was scored (1=not, 10=very) based on pre and post practice surveys: realism (tissue pliability, papilla anatomy, visual/cannulation realism, wire manipulation, simulated fluoroscopy, overall experience); usefulness (assessment of results, supplementing clinical experience, easy for trainees to learn new skills) and application (overall ease of use, prepare trainees to use real instrument and ease of incorporation into training). RESULTS: Before hands-on practice, both EMS and PSM received high scores. After practice, there was a significantly greater increase in confidence score for EMS than PSM (p<0.003). Participants found EMS more useful for training (p=0.017). LIMITATIONS: Subjective scores. CONCLUSIONS: Based on head-to-head hands-on comparison, endoscopists considered both EMS and PSM credible options for improving understanding and supplementing clinical ERCP training. EMS is more useful for basic learning.

  10. Head-to-Head Comparison of Three Vaccination Strategies Based on DNA and Raw Insect-Derived Recombinant Proteins against Leishmania

    PubMed Central

    Núñez, María del Carmen; Laurenti, Márcia D.; Gómez-Sebastián, Silvia; Rodríguez, Fernando; Pérez-Martín, Eva; Escribano, José M.

    2012-01-01

    Parasitic diseases plague billions of people among the poorest, killing millions annually, and causing additional millions of disability-adjusted life years lost. Leishmaniases affect more than 12 million people, with over 350 million people at risk. There is an urgent need for efficacious and cheap vaccines and treatments against visceral leishmaniasis (VL), its most severe form. Several vaccination strategies have been proposed but to date no head-to-head comparison was undertaken to assess which is the best in a clinical model of the disease. We simultaneously assayed three vaccination strategies against VL in the hamster model, using KMPII, TRYP, LACK, and PAPLE22 vaccine candidate antigens. Four groups of hamsters were immunized using the following approaches: 1) raw extracts of baculovirus-infected Trichoplusia ni larvae expressing individually one of the four recombinant proteins (PROT); 2) naked pVAX1 plasmids carrying the four genes individually (DNA); 3) a heterologous prime-boost (HPB) strategy involving DNA followed by PROT (DNA-PROT); and 4) a Control including empty pVAX1 plasmid followed by raw extract of wild-type baculovirus-infected T. ni larvae. Hamsters were challenged with L. infantum promastigotes and maintained for 20 weeks. While PROT vaccine was not protective, DNA vaccination achieved protection in spleen. Only DNA-PROT vaccination induced significant NO production by macrophages, accompanied by a significant parasitological protection in spleen and blood. Thus, the DNA-PROT strategy elicits strong immune responses and high parasitological protection in the clinical model of VL, better than its corresponding naked DNA or protein versions. Furthermore, we show that naked DNA coupled with raw recombinant proteins produced in insect larvae biofactories –the cheapest way of producing DNA-PROT vaccines– is a practical and cost-effective way for potential “off the shelf” supplying vaccines at very low prices for the protection against

  11. Head-to-head comparison of three vaccination strategies based on DNA and raw insect-derived recombinant proteins against Leishmania.

    PubMed

    Todolí, Felicitat; Rodríguez-Cortés, Alhelí; Núñez, María Del Carmen; Laurenti, Márcia D; Gómez-Sebastián, Silvia; Rodríguez, Fernando; Pérez-Martín, Eva; Escribano, José M; Alberola, Jordi

    2012-01-01

    Parasitic diseases plague billions of people among the poorest, killing millions annually, and causing additional millions of disability-adjusted life years lost. Leishmaniases affect more than 12 million people, with over 350 million people at risk. There is an urgent need for efficacious and cheap vaccines and treatments against visceral leishmaniasis (VL), its most severe form. Several vaccination strategies have been proposed but to date no head-to-head comparison was undertaken to assess which is the best in a clinical model of the disease. We simultaneously assayed three vaccination strategies against VL in the hamster model, using KMPII, TRYP, LACK, and PAPLE22 vaccine candidate antigens. Four groups of hamsters were immunized using the following approaches: 1) raw extracts of baculovirus-infected Trichoplusia ni larvae expressing individually one of the four recombinant proteins (PROT); 2) naked pVAX1 plasmids carrying the four genes individually (DNA); 3) a heterologous prime-boost (HPB) strategy involving DNA followed by PROT (DNA-PROT); and 4) a Control including empty pVAX1 plasmid followed by raw extract of wild-type baculovirus-infected T. ni larvae. Hamsters were challenged with L. infantum promastigotes and maintained for 20 weeks. While PROT vaccine was not protective, DNA vaccination achieved protection in spleen. Only DNA-PROT vaccination induced significant NO production by macrophages, accompanied by a significant parasitological protection in spleen and blood. Thus, the DNA-PROT strategy elicits strong immune responses and high parasitological protection in the clinical model of VL, better than its corresponding naked DNA or protein versions. Furthermore, we show that naked DNA coupled with raw recombinant proteins produced in insect larvae biofactories -the cheapest way of producing DNA-PROT vaccines- is a practical and cost-effective way for potential "off the shelf" supplying vaccines at very low prices for the protection against

  12. A Head-to-Head Comparison of Four Artemisinin-Based Combinations for Treating Uncomplicated Malaria in African Children: A Randomized Trial

    PubMed Central

    2011-01-01

    Background Artemisinin-based combination therapies (ACTs) are the mainstay for the management of uncomplicated malaria cases. However, up-to-date data able to assist sub-Saharan African countries formulating appropriate antimalarial drug policies are scarce. Methods and Findings Between 9 July 2007 and 19 June 2009, a randomized, non-inferiority (10% difference threshold in efficacy at day 28) clinical trial was carried out at 12 sites in seven sub-Saharan African countries. Each site compared three of four ACTs, namely amodiaquine-artesunate (ASAQ), dihydroartemisinin-piperaquine (DHAPQ), artemether-lumefantrine (AL), or chlorproguanil-dapsone-artesunate (CD+A). Overall, 4,116 children 6–59 mo old with uncomplicated Plasmodium falciparum malaria were treated (1,226 with AL, 1,002 with ASAQ, 413 with CD+A, and 1,475 with DHAPQ), actively followed up until day 28, and then passively followed up for the next 6 mo. At day 28, for the PCR-adjusted efficacy, non-inferiority was established for three pair-wise comparisons: DHAPQ (97.3%) versus AL (95.5%) (odds ratio [OR]: 0.59, 95% CI: 0.37–0.94); DHAPQ (97.6%) versus ASAQ (96.8%) (OR: 0.74, 95% CI: 0.41–1.34), and ASAQ (97.1%) versus AL (94.4%) (OR: 0.50, 95% CI: 0.28–0.92). For the PCR-unadjusted efficacy, AL was significantly less efficacious than DHAPQ (72.7% versus 89.5%) (OR: 0.27, 95% CI: 0.21–0.34) and ASAQ (66.2% versus 80.4%) (OR: 0.40, 95% CI: 0.30–0.53), while DHAPQ (92.2%) had higher efficacy than ASAQ (80.8%) but non-inferiority could not be excluded (OR: 0.35, 95% CI: 0.26–0.48). CD+A was significantly less efficacious than the other three treatments. Day 63 results were similar to those observed at day 28. Conclusions This large head-to-head comparison of most currently available ACTs in sub-Saharan Africa showed that AL, ASAQ, and DHAPQ had excellent efficacy, up to day 63 post-treatment. The risk of recurrent infections was significantly lower for DHAPQ, followed by ASAQ and then AL

  13. Head-to-head comparisons of metabolic side effects of second generation antipsychotics in the treatment of schizophrenia: a systematic review and meta-analysis

    PubMed Central

    Rummel-Kluge, Christine; Komossa, Katja; Schwarz, Sandra; Hunger, Heike; Schmid, Franziska; Lobos, Claudia Asenjo; Kissling, Werner; Davis, John M; Leucht, Stefan

    2010-01-01

    Objective The metabolic side effects of second-generation antipsychotics (SGA) are serious and have not been compared head to head in a meta-analysis. We conducted a meta-analysis of studies comparing the metabolic side effects of the following SGAs head-to-head: amisulpride, aripiprazole, clozapine, olanzapine, quetiapine, risperidone, sertindole, ziprasidone, zotepine. Method We searched the register of the Cochrane schizophrenia group (last search May 2007), supplemented by MEDLINE and EMBASE (last search January 2009) for randomized, blinded studies comparing the above mentioned SGA in the treatment of schizophrenia or related disorders. At least three reviewers extracted the data independently. The primary outcome was weight change. We also assessed changes of cholesterol and glucose. The results were combined in a meta-analysis. Results We included 48 studies with 105 relevant arms. Olanzapine produced more weight gain than all other second-generation antipsychotics except for clozapine where no difference was found. Clozapine produced more weight gain than risperidone, risperidone more than amisulpride, and sertindole more than risperidone. Olanzapine produced more cholesterol increase than aripiprazole, risperidone and ziprasidone. (No differences with amisulpride, clozapine and quetiapine were found). Quetiapine produced more cholesterol increase than risperidone and ziprasidone. Olanzapine produced more increase in glucose than amisulpride, aripiprazole, quetiapine, risperidone and ziprasidone; no difference was found with clozapine. Conclusions Some SGAs lead to substantially more metabolic side effects than other SGAs. When choosing an SGA for an individual patient these side effects with their potential cause of secondary diseases must be weighed against efficacy and characteristics of the individual patient. PMID:20692814

  14. Star-shape redox-responsive PEG-sheddable copolymer of disulfide-linked polyethylene glycol-lysine-di-tocopherol succinate for tumor-triggering intracellular doxorubicin rapid release: head-to-head comparison.

    PubMed

    Ai, Xiaoyu; Sun, Jin; Zhong, Lu; Wu, Chunnuan; Niu, Handong; Xu, Tao; Lian, He; Han, Xiaopeng; Ren, Guolian; Ding, Wenya; Wang, Jia; Pu, Xiaohui; He, Zhonggui

    2014-10-01

    A redox-responsive poly(ethylene glycol) (PEG)-sheddable copolymer of disulfide-linked PEG 5000-lysine-di-tocopherol succinate (P(5k)SSLV) is developed which can self-assemble into nanomicelles in aqueous condition and trigger the rapid release of encapsulated drugs within tumor cells. The reduction-insensitive doxorubicin (DOX)-loaded P(5k)LV (P(5k)LV-DOX) nanomicelles are further prepared. Then head-to-head comparison of P(5k)SSLV-DOX, P(5k)LV-DOX and DOX-Sol is performed concerning in vitro release, cytotoxicity, cellular uptake and apoptosis. Results show that P(5k)SSLV-DOX nanomicelles have a faster DOX release, a higher anti-tumor activity and more DOX concentrating in the nucleus than P(5k)LV-DOX nanomicelles. In conclusion, the redox-responsive P(5k)SSLV nanomicelles might hold a great potential to improve chemotherapy by tumor-triggering intracellular rapid release. The outcomes of this study also address the significance of such head-to-head comparison studies in translational research of nanomedicine.

  15. Pharmacoeconomic comparison of aripiprazole once-monthly and paliperidone palmitate from a head-to-head clinical trial in schizophrenia: a US analysis

    PubMed Central

    Sapin, Christophe; Hartry, Ann; Kamat, Siddhesh A.; Beillat, Maud; Baker, Ross A.; Eramo, Anna

    2016-01-01

    Schizophrenia presents a substantial clinical and economic burden to the health-care system. In QUAlity of LIfe with AbiliFY Maintena (QUALIFY), a randomized head-to-head study of aripiprazole once-monthly 400 mg (AOM 400) compared with paliperidone palmitate (PP; 78–234 mg/mo), AOM 400 demonstrated greater improvement in health-related quality of life and functioning in patients with stable schizophrenia. The present analysis used health economics assessment data collected during the QUALIFY study to determine the direct medical and pharmacy costs and the cost-effectiveness associated with each treatment over 6 months. Compared with those receiving PP, patients receiving AOM 400 incurred significantly lower direct total costs ($8908±186 vs $9675±190, p=0.005) and treatment costs ($7967±113 vs $8706±116, p<0.001). Effectiveness results in the subset of patients included in the cost analyses were similar to the overall population: mean (95% CI) improvement in Heinrichs-Carpenter Quality of Life Scale total score was greater with AOM 400 (5.97 [3.87; 8.08]) compared with PP (2.85 [0.56; 5.08]). Likewise, Clinical Global Impression–Severity improved more in the AOM 400 group (−0.59 [−0.71; −0.47]) compared with PP group (−0.37 [−0.46; −0.27]). Therefore, the analysis of data from stabilized patients with schizophrenia in the QUALIFY study indicated that AOM 400 is associated with lower health-care costs and greater effectiveness compared with PP and thus represents the economically dominant strategy. PMID:27708677

  16. Direct head-to-head comparison of cationic liposome-mediated gene delivery to mesenchymal stem/stromal cells of different human sources: a comprehensive study.

    PubMed

    Boura, Joana S; Santos, Francisco Dos; Gimble, Jeffrey M; Cardoso, Carla M P; Madeira, Catarina; Cabral, Joaquim M S; Silva, Cláudia Lobato da

    2013-02-01

    Nonviral gene delivery to human mesenchymal stem/stromal cells (MSC) can be considered a very promising strategy to improve their intrinsic features, amplifying the therapeutic potential of these cells for clinical applications. In this work, we performed a comprehensive comparison of liposome-mediated gene transfer efficiencies to MSC derived from different human sources-bone marrow (BM MSC), adipose tissue-derived cells (ASC), and umbilical cord matrix (UCM MSC). The results obtained using a green fluorescent protein (GFP)-encoding plasmid indicated that MSC isolated from BM and UCM are more amenable to genetic modification when compared to ASC as they exhibited superior levels of viable, GFP(+) cells 48 hr post-transfection, 58 ± 7.1% and 54 ± 3.8%, respectively, versus 33 ± 4.7%. For all cell sources, high cell recoveries (≈50%) and viabilities (>85%) were achieved, and the transgene expression was maintained for 10 days. Levels of plasmid DNA uptake, as well as kinetics of transgene expression and cellular division, were also determined. Importantly, modified cells were found to retain their characteristic immunophenotypic profile and multilineage differentiation capacity. By using the lipofection protocol optimized herein, we were able to maximize transfection efficiencies to human MSC (maximum of 74% total GFP(+) cells) and show that lipofection is a promising transfection strategy for MSC genetic modification, especially when a transient expression of a therapeutic gene is required. Importantly, we also clearly demonstrated that intrinsic features of MSC from different sources should be taken into consideration when developing and optimizing strategies for MSC engineering with a therapeutic gene.

  17. Accuracy and precision of pseudo-continuous arterial spin labeling perfusion during baseline and hypercapnia: a head-to-head comparison with ¹⁵O H₂O positron emission tomography.

    PubMed

    Heijtel, D F R; Mutsaerts, H J M M; Bakker, E; Schober, P; Stevens, M F; Petersen, E T; van Berckel, B N M; Majoie, C B L M; Booij, J; van Osch, M J P; Vanbavel, E; Boellaard, R; Lammertsma, A A; Nederveen, A J

    2014-05-15

    Measurements of the cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) provide useful information about cerebrovascular condition and regional metabolism. Pseudo-continuous arterial spin labeling (pCASL) is a promising non-invasive MRI technique to quantitatively measure the CBF, whereas additional hypercapnic pCASL measurements are currently showing great promise to quantitatively assess the CVR. However, the introduction of pCASL at a larger scale awaits further evaluation of the exact accuracy and precision compared to the gold standard. (15)O H₂O positron emission tomography (PET) is currently regarded as the most accurate and precise method to quantitatively measure both CBF and CVR, though it is one of the more invasive methods as well. In this study we therefore assessed the accuracy and precision of quantitative pCASL-based CBF and CVR measurements by performing a head-to-head comparison with (15)O H₂O PET, based on quantitative CBF measurements during baseline and hypercapnia. We demonstrate that pCASL CBF imaging is accurate during both baseline and hypercapnia with respect to (15)O H₂O PET with a comparable precision. These results pave the way for quantitative usage of pCASL MRI in both clinical and research settings.

  18. Head-to-head comparison of second-generation nucleic acid amplification tests for detection of Chlamydia trachomatis and Neisseria gonorrhoeae on urine samples from female subjects and self-collected vaginal swabs.

    PubMed

    Chernesky, Max; Jang, Dan; Gilchrist, Jodi; Hatchette, Todd; Poirier, André; Flandin, Jean-Frederic; Smieja, Marek; Ratnam, Sam

    2014-07-01

    In a comparison of 4 second-generation nucleic acid amplification tests performed with self-collected vaginal swab (SCVS) and first-void urine (FVU) specimens from 575 women, SCVS specimens indicated more infections than did FVU specimens in all assays. The prevalence rates were 9% (53/575 patients) for Chlamydia trachomatis and 2% (11/575 patients) for Neisseria gonorrhoeae. The clinical sensitivities for testing SCVS specimens for C. trachomatis were 98.1% on a Tigris system and 96.2% on a Panther system for the Aptima Combo 2 assay (Hologic Gen-Probe), 98.0% for the RealTime CT/NG assay on an m2000 instrument (Abbott), 90.6% for the ProbeTec CT/GC Q(x) assay on the Viper system (Becton Dickinson), and 84.6% for the cobas CT/NG assay on the cobas 4800 platform (Roche). Clinical sensitivities for C. trachomatis in FVU specimens were 88.7% (Tigris) and 88.0% (Panther) for the Aptima Combo 2 assay, 76.9% for the RealTime CT/NG assay, 75.5% for the ProbeTec CT/GC Q(x) assay, and 81.1% for the cobas CT/NG assay. Clinical sensitivities of the assays for N. gonorrhoeae, with limited positive results, ranged from 63.6% to 100%. Specificities for both infections ranged from 98.4 to 100%. Differences in analytical sensitivities and levels of molecular targets in clinical samples but not inhibitors of amplification may explain the differences in clinical sensitivities.

  19. Prognostic Value of 18F-FLT PET in Patients with Neuroendocrine Neoplasms: A Prospective Head-to-Head Comparison with 18F-FDG PET and Ki-67 in 100 Patients.

    PubMed

    Johnbeck, Camilla B; Knigge, Ulrich; Langer, Seppo W; Loft, Annika; Berthelsen, Anne Kiil; Federspiel, Birgitte; Binderup, Tina; Kjaer, Andreas

    2016-12-01

    Neuroendocrine neoplasms (NENs) constitute a heterogeneous group of tumors arising in various organs and with a large span of aggressiveness and survival rates. The Ki-67 proliferation index is presently used as the key marker of prognosis, and treatment guidelines are largely based on this index. 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) is a proliferation tracer for PET imaging valuable in the monitoring of disease progression and treatment response in various types of cancer. However, until now only data from 10 patients with NEN were available in the literature. The aim of the present study was to investigate (18)F-FLT PET as a prognostic marker for NENs in comparison with (18)F-FDG PET and Ki-67 index.

  20. Head-to-head and tail-to-tail 180° domain walls in an isolated ferroelectric

    NASA Astrophysics Data System (ADS)

    Gureev, M. Y.; Tagantsev, A. K.; Setter, N.

    2011-05-01

    Head-to-head and tail-to-tail 180° domain walls in a finite isolated ferroelectric sample are theoretically studied using Landau theory. The full set of equations, suitable for numerical calculations, is developed. The explicit expressions for the polarization profile across the walls are derived for several limiting cases and wall widths are estimated. It is shown analytically that different regimes of screening and different dependences for the width of charged domain walls on the temperature and parameters of the system are possible, depending on spontaneous polarization and concentration of carriers in the material. It is shown that the half-width of charged domain walls in typical perovskites is about the nonlinear Thomas-Fermi screening length and about one order of magnitude larger than the half-width of neutral domain walls. The formation energies of head-to-head walls under different regimes of screening are obtained, neglecting the poling ability of the surface. In the nonlinear regimes of screening, this energy is equal to the energy necessary for the creation of electron-hole pairs in the amount sufficient to screen the spontaneous polarization, which is proportional to the band gap of the ferroelectric. It is shown that either head-to-head or tail-to-tail configurations can be energetically favorable in comparison with the monodomain state of the ferroelectric if the poling ability of the surface is large enough. If this is not the case, the existence of charged domain walls in bulk ferroelectrics is merely a result of the domain-growth kinetics. Formation energies of the other possible states, i.e., the multidomain state with antiparallel domains separated by neutral walls and the state with the zero polarization, were compared with the formation energy of the charged domain wall. It was shown that, at large enough sample thicknesses, a charged domain wall can be energetically favorable in comparison with the states mentioned above. This size effect

  1. Dialkoxybithiazole: a new building block for head-to-head polymer semiconductors.

    PubMed

    Guo, Xugang; Quinn, Jordan; Chen, Zhihua; Usta, Hakan; Zheng, Yan; Xia, Yu; Hennek, Jonathan W; Ortiz, Rocío Ponce; Marks, Tobin J; Facchetti, Antonio

    2013-02-06

    Polymer semiconductors have received great attention for organic electronics due to the low fabrication cost offered by solution-based printing techniques. To enable the desired solubility/processability and carrier mobility, polymers are functionalized with hydrocarbon chains by strategically manipulating the alkylation patterns. Note that head-to-head (HH) linkages have traditionally been avoided because the induced backbone torsion leads to poor π-π overlap and amorphous film microstructures, and hence to low carrier mobilities. We report here the synthesis of a new building block for HH linkages, 4,4'-dialkoxy-5,5'-bithiazole (BTzOR), and its incorporation into polymers for high performance organic thin-film transistors. The small oxygen van der Waals radius and intramolecular S(thiazolyl)···O(alkoxy) attraction promote HH macromolecular architectures with extensive π-conjugation, low bandgaps (1.40-1.63 eV), and high crystallinity. In comparison to previously reported 3,3'-dialkoxy-2,2'-bithiophene (BTOR), BTzOR is a promising building block in view of thiazole geometric and electronic properties: (a) replacing (thiophene)C-H with (thiazole)N reduces steric encumbrance in -BTzOR-Ar- dyads by eliminating repulsive C-H···H-C interactions with neighboring arene units, thereby enhancing π-π overlap and film crystallinity; and (b) thiazole electron-deficiency compensates alkoxy electron-donating characteristics, thereby lowering the BTzOR polymer HOMO versus that of the BTOR analogues. Thus, the new BTzOR polymers show substantial hole mobilities (0.06-0.25 cm(2)/(V s)) in organic thin-film transistors, as well as enhanced I(on):I(off) ratios and greater ambient stability than the BTOR analogues. These geometric and electronic properties make BTzOR a promising building block for new classes of polymer semiconductors, and the synthetic route to BTzOR reported here should be adaptable to many other bithiazole-based building blocks.

  2. Are head-to-head trials of biologics needed? The role of value of information methods in arthritis research.

    PubMed

    Welton, Nicky J; Madan, Jason; Ades, Anthony E

    2011-09-01

    Reimbursement decisions are typically based on cost-effectiveness analyses. While a cost-effectiveness analysis can identify the optimum strategy, there is usually some degree of uncertainty around this decision. Sources of uncertainty include statistical sampling error in treatment efficacy measures, underlying baseline risk, utility measures and costs, as well as uncertainty in the structure of the model. The optimal strategy is therefore only optimal on average, and a decision to adopt this strategy might still be the wrong decision if all uncertainty could be eliminated. This means that there is a quantifiable expected (average) loss attaching to decisions made under uncertainty, and hence a value in collecting information to reduce that uncertainty. Value of information (VOI) analyses can be used to provide guidance on whether more research would be cost-effective, which particular model inputs (parameters) have the most bearing on decision uncertainty, and can also help with the design and sample size of further research. Here, we introduce the key concepts in VOI analyses, and highlight the inputs required to calculate it. The adoption of the new biologic treatments for RA and PsA tends to be based on placebo-controlled trials. We discuss the possible role of VOI analyses in deciding whether head-to-head comparisons of the biologic therapies should be carried out, illustrating with examples from other fields. We emphasize the need for a model of the natural history of RA and PsA, which reflects a consensus view.

  3. Long-acting methylphenidate formulations in the treatment of attention-deficit/hyperactivity disorder: a systematic review of head-to-head studies

    PubMed Central

    2013-01-01

    Background The stimulant methylphenidate (MPH) has been a mainstay of treatment for attention-deficit/hyperactivity disorder (ADHD) for many years. Owing to the short half-life and the issues associated with multiple daily dosing of immediate-release MPH formulations, a new generation of long-acting MPH formulations has emerged. Direct head-to-head studies of these long-acting MPH formulations are important to facilitate an evaluation of their comparative pharmacokinetics and efficacy; however, to date, relatively few head-to-head studies have been performed. The objective of this systematic review was to compare the evidence available from head-to-head studies of long-acting MPH formulations and provide information that can guide treatment selection. Methods A systematic literature search was conducted in MEDLINE and PsycINFO in March 2012 using the MeSH terms: attention deficit disorder with hyperactivity/drug therapy; methylphenidate/therapeutic use and All Fields: Concerta; Ritalin LA; OROS and ADHD; Medikinet; Equasym XL and ADHD; long-acting methylphenidate; Diffucaps and ADHD; SODAS and methylphenidate. No filters were applied and no language, publication date or publication status limitations were imposed. Articles were selected if the title indicated a comparison of two or more long-acting MPH preparations in human subjects of any age; non-systematic review articles and unpublished data were not included. Results Of 15,295 references returned in the literature search and screened by title, 34 articles were identified for inclusion: nine articles from pharmacokinetic studies (nine studies); nine articles from laboratory school studies (six studies); two articles from randomized controlled trials (two studies); three articles from switching studies (two studies) and three articles from one observational study. Conclusions Emerging head-to-head studies provide important data on the comparative efficacy of the formulations available. At a group level, efficacy

  4. Head-to-head running race simulation alters pacing strategy, performance, and mood state.

    PubMed

    Tomazini, Fabiano; Pasqua, Leonardo A; Damasceno, Mayara V; Silva-Cavalcante, Marcos D; de Oliveira, Fernando R; Lima-Silva, Adriano E; Bertuzzi, Rômulo

    2015-10-01

    The objective of this study was to analyze the influence of the presence and absence of competitors on pacing, overall running performance, and mood state during a self-paced 3-km run. Nine recreational runners participated in this study. They performed the following tests: a) an incremental test to exhaustion to measure the respiratory compensation point (RCP), maximal oxygen uptake, and peak treadmill speed; b) a submaximal speed constant test to measure running economy; and c) two 3-km running time trials performed collectively (COL, head-to-head competition) or individually (IND, performed alone) to establish pacing and running performance. The COL condition was formed of a group of four runners or five runners. Runners were grouped by matched performance times and to retain head-to-head characteristics.A mood state profile questionnaire was completed before and after the 3-km running time trial. The overall performance was better in the COL than in the IND (11.75 ± 0.05 min vs. 12.25 ± 0.06 min, respectively; p = 0.04). The running speeds during the first 500 m were significantly greater in COL (16.8 ± 2.16 km·h−1) than in IND (15.3 ± 2.45 km·h−1) (p = 0.03).The gain in running speed from IND to COL during the first 400 m (i.e. running speed in COL less running speed in IND) was significantly correlated with the RCP (r = 0.88; p = 0.05). The vigor score significantly decreased from pre- to post-running in COL (p=0.05), but not in IND (p=0.20). Additionally, the post running vigor was significantly higher in IND compared to COL (p = 0.03).These findings suggested that the presence of competitors induces a fast start, which results in an improved overall performance and reduced post-exercise vigor scores, compared to an individual run.

  5. POP-pincer osmium-polyhydrides: head-to-head (Z)-dimerization of terminal alkynes.

    PubMed

    Alós, Joaquín; Bolaño, Tamara; Esteruelas, Miguel A; Oliván, Montserrat; Oñate, Enrique; Valencia, Marta

    2013-05-20

    A wide range of osmium-polyhydride complexes stabilized by the POP-pincer ligand xant(P(i)Pr2)2 (9,9-dimethyl-4,5-bis(diisopropylphosphino)xanthene) have been synthesized through cis-OsCl2{κ-S-(DMSO)4} (1, DMSO = dimethyl sulfoxide). Treatment of toluene solutions of this adduct with the diphosphine, under reflux, leads to OsCl2{xant(P(i)Pr2)2}(κ-S-DMSO) (2). The reaction of 2 with H2 in the presence of Et3N affords OsH3Cl{xant(P(i)Pr2)2} (3), which can be also prepared by addition of xant(P(i)Pr2)2 to toluene solutions of the unsaturated d(4)-trihydride OsH3Cl(P(i)Pr3)2 (5). Complex 3 reductively eliminates H2 in toluene at 90 °C. In the presence of dimethyl sulfoxide, the resulting monohydride is trapped by the S-donor molecule to give OsHCl{xant(P(i)Pr2)2}(κ-S-DMSO) (6). The reaction of 2 with H2 is sensible to the Brønsted base. Thus, in contrast to Et3N, NaH removes both chloride ligands and the hexahydride OsH6{xant(P(i)Pr2)2} (7), containing a κ(2)-P-binding diphosphine, is formed under 3 atm of hydrogen at 50 °C. Complex 7 releases a H2 molecule to yield the tetrahydride OsH4{xant(P(i)Pr2)2} (8), which can be also prepared by reaction of OsH6(P(i)Pr3)2 (9) with xant(P(i)Pr2)2. Complex 8 reduces H(+) to give, in addition to H2, the oxidized OsH4-species [OsH4(OTf){xant(P(i)Pr2)2}](+) (10, OTf = trifluoromethanesulfonate). The redox process occurs in two stages via the OsH5-cation [OsH5{xant(P(i)Pr2)2}](+) (11). The metal oxidation state four can be recovered. The addition of acetonitrile to 10 leads to [OsH2(η(2)-H2)(CH3CN){xant(P(i)Pr2)2}](2+) (12). The deprotonation of 12 yields the osmium(IV) trihydride [OsH3(CH3CN){xant(P(i)Pr2)2}](+) (13), which is also formed by addition of HOTf to the acetonitrile solutions of 8. The latter is further an efficient catalyst precursor for the head-to-head (Z)-dimerization of phenylacetylene and tert-butylacetylene. During the activation process of the tetrahydride, the bis(alkynyl)vinylidene derivatives Os

  6. The Science of Racing against Opponents: Affordance Competition and the Regulation of Exercise Intensity in Head-to-Head Competition

    PubMed Central

    Hettinga, Florentina J.; Konings, Marco J.; Pepping, Gert-Jan

    2017-01-01

    Athlete–environment interactions are crucial factors in understanding the regulation of exercise intensity in head-to-head competitions. Previously, we have proposed a framework based on the interdependence of perception and action, which allows us to explore athletic behavior in the more complex pacing situations occurring when athletes need to respond to actions of their opponents. In the present perspective we will further explore whether opponents, crucial external factors in competitive sports, could indeed be perceived as social invitations for action. Decisions regarding how to expend energy over the race are based on internal factors such as the physiological/biomechanical capacity of the athlete in relation to external factors such as those presented by opponents. For example: Is the athlete able to overtake competitors, or not? We present several experimental studies that demonstrate that athletes regulate their exercise intensity differently in head-to-head competition compared to time-trial exercises: Relational athlete-environment aspects seem to outweigh benefits of the individual optimal energy distribution. Also, the behavior of the opponents has been shown to influence pacing strategies of competing athletes, again demonstrating the importance of relational athlete–environment aspects in addition to strictly internal factors. An ecological perspective is presented in which opponents are proposed to present social affordances, and decision-making is conceptualized as a resultant of affordance-competition. This approach will provide novel insights in tactical decision-making and pacing behavior in head-to-head competitions. Future research should not only focus on the athlete's internal state, but also try to understand opponents in the context of the social affordances they provide. PMID:28293199

  7. The Science of Racing against Opponents: Affordance Competition and the Regulation of Exercise Intensity in Head-to-Head Competition.

    PubMed

    Hettinga, Florentina J; Konings, Marco J; Pepping, Gert-Jan

    2017-01-01

    Athlete-environment interactions are crucial factors in understanding the regulation of exercise intensity in head-to-head competitions. Previously, we have proposed a framework based on the interdependence of perception and action, which allows us to explore athletic behavior in the more complex pacing situations occurring when athletes need to respond to actions of their opponents. In the present perspective we will further explore whether opponents, crucial external factors in competitive sports, could indeed be perceived as social invitations for action. Decisions regarding how to expend energy over the race are based on internal factors such as the physiological/biomechanical capacity of the athlete in relation to external factors such as those presented by opponents. For example: Is the athlete able to overtake competitors, or not? We present several experimental studies that demonstrate that athletes regulate their exercise intensity differently in head-to-head competition compared to time-trial exercises: Relational athlete-environment aspects seem to outweigh benefits of the individual optimal energy distribution. Also, the behavior of the opponents has been shown to influence pacing strategies of competing athletes, again demonstrating the importance of relational athlete-environment aspects in addition to strictly internal factors. An ecological perspective is presented in which opponents are proposed to present social affordances, and decision-making is conceptualized as a resultant of affordance-competition. This approach will provide novel insights in tactical decision-making and pacing behavior in head-to-head competitions. Future research should not only focus on the athlete's internal state, but also try to understand opponents in the context of the social affordances they provide.

  8. Is there evidence for recommending specific intravenous immunoglobulin formulations? A systematic review of head-to-head randomized controlled trials.

    PubMed

    Buehler, Anna Maria; Flato, Uri P; Ferri, Cleusa P; Fernandes, Jefferson G

    2015-01-15

    Intravenous immunoglobulins (IVIG) have been used for several licensed and off-label indications. Each IVIG product is a unique formulation of IgG and excipients, making them distinct products. How these differences impact on individual IVIG product efficacy and safety are not well established but can be investigated by head-to-head randomized controlled trials (RCT). A systematic review of head-to-head RCT comparing different formulations of IVIG, regardless of the target condition and outcomes investigated. Two reviewers screened 4084 citations retrieved from MEDLINE, Embase, Cochrane and LILACS, and 23 citations were fully-text evaluated. Eight trials were included. The clinical conditions, outcomes and risk of bias were assessed. Of the eight trials included only two investigated products that are currently on the market. One evaluated two Grifols brands used in patients with primary immunodeficiency and another evaluated two Baxter brands used in patients with chronic inflammatory demyelinating polyradiculoneuropathy. There were no differences between the formulations for the outcomes evaluated. In the other trials, either the manufacturers were acquired by other companies or the formulation was withdrawn from the market. As consequence, evidence concerning these products could not be considered. The quality of the studies was low, showing high risk of bias. Direct evidence about the different IVIGs is scarce and, at present, there is no scientific evidence that can be applied for a specific brand or formulation. Further comparative effectiveness studies are highly desirable for a better understanding of the differences in safety and efficacy of IVIGs.

  9. Crystal structure of head-to-head dimers of cholic and deoxycholic acid derivatives with different symmetric bridges.

    PubMed

    Meijide, Francisco; Trillo, Juan V; de Frutos, Santiago; Galantini, Luciano; Pavel, Nicolae Viorel; Soto, Victor H; Jover, Aida; Tato, José Vázquez

    2013-02-01

    The crystal structure of three head-to-head dimers (having two cholic acid or deoxycholic acid units) linked at carbon atoms C3 by aromatic or alkyl bridges is studied. An internal coordinates system is necessary for describing the relative orientation in the space of the two bile acid residues. Five angles (three torsion and two common ones) are necessary for defining the relative position of both steroid residues in space. Carbon atoms C3 (which always carries a α-hydroxy group in natural bile acids), and C10 and C13 (which always carry β-methyl groups) of each steroid residue are suitable for this purpose. Furthermore, the distance between each C3 carbon atoms of both steroid residues will allow one to locate the steroids in space. The three dimers selected provide a large range of values for these angles. The packing, hydrogen bond network, and location of guest in the three crystals are discussed.

  10. Combined albumin and bicarbonate induces head-to-head sperm agglutination which physically prevents equine sperm-oviduct binding.

    PubMed

    Leemans, Bart; Gadella, Bart M; Stout, Tom A E; Sostaric, Edita; De Schauwer, Catharina; Nelis, Hilde; Hoogewijs, Maarten; Van Soom, Ann

    2016-04-01

    In many species, sperm binding to oviduct epithelium is believed to be an essential step in generating a highly fertile capacitated sperm population primed for fertilization. In several mammalian species, this interaction is based on carbohydrate-lectin recognition. D-galactose has previously been characterized as a key molecule that facilitates sperm-oviduct binding in the horse. We used oviduct explant and oviduct apical plasma membrane (APM) assays to investigate the effects of various carbohydrates; glycosaminoglycans; lectins; S-S reductants; and the capacitating factors albumin, Ca(2+) and HCO3(-) on sperm-oviduct binding in the horse. Carbohydrate-specific lectin staining indicated that N-acetylgalactosamine, N-acetylneuraminic acid (sialic acid) and D-mannose or D-glucose were the most abundant carbohydrates on equine oviduct epithelia, whereas D-galactose moieties were not detected. However, in a competitive binding assay, sperm-oviduct binding density was not influenced by any tested carbohydrates, glycosaminoglycans, lectins or D-penicillamine, nor did the glycosaminoglycans induce sperm tail-associated protein tyrosine phosphorylation. Furthermore, N-glycosidase F (PNGase) pretreatment of oviduct explants and APM did not alter sperm-oviduct binding density. By contrast, a combination of the sperm-capacitating factors albumin and HCO3(-) severely reduced (>10-fold) equine sperm-oviduct binding density by inducing rapid head-to-head agglutination, both of which events were independent of Ca(2+) and an elevated pH (7.9). Conversely, neither albumin and HCO3(-) nor any other capacitating factor could induce release of oviduct-bound sperm. In conclusion, a combination of albumin and HCO3(-) markedly induced sperm head-to-head agglutination which physically prevented stallion sperm to bind to oviduct epithelium.

  11. Extracellular calcium is involved in egg yolk-induced head-to-head agglutination of bull sperm.

    PubMed

    Yang, D H; McMillan, A G; Standley, N T; Shannon, P; Xu, Z Z

    2012-10-15

    Head-to-head agglutination of bull sperm occurs when semen is highly diluted in an egg yolk-citrate diluent without streptomycin. The objectives were to investigate causes of sperm agglutination and the underlying mechanism. Aliquots of bull semen were diluted in a base diluent (BD) supplemented with various test components and the percentage of agglutinated sperm (% AggSp) was quantified at 1, 5, 24, 48, and 72 h of incubation. When sperm were incubated at 22 °C, no agglutination was observed in BD for up to 72 h, whereas the % AggSp was 5.0, 41.7, 72.2, 91.1, and 92.8% in BD + 5% egg yolk (BD + EY) at 1, 5, 24, 48 and 72 h, respectively. However, no sperm agglutination was observed in BD + EY if incubation temperature was 37 °C. Addition of 5 or 10 mM ethylenebis (oxyethyleneni-trilo) tetra-acetic acid to BD + EY reduced the % AggSp from 95% to <5% at 72 h (P < 0.001), but addition of 5 mM CaCl(2) to BD failed to induce sperm agglutination in the absence of egg yolk, implicating calcium and other factors in egg yolk. Addition of the citrate-soluble fraction (CSF) of egg yolk to BD induced sperm agglutination similar to whole egg yolk, whereas water- and saline-soluble fractions of egg yolk were ineffective. The sperm-agglutinating efficacy of CSF (the % AggSp = 95% at 72 h) was reduced by dialysis (20%; P < 0.05), partially restored by addition of 5 mM CaCl2 (70%; P < 0.05), but the calcium effect was neutralized by addition of 5 mM ethylenebis (oxyethyleneni-trilo) tetra-acetic acid (1.7%; P < 0.05), again implicating calcium. Addition of 30 μM of a protein kinase A inhibitor (H-89) to an agglutinating diluent failed to inhibit sperm agglutination, whereas addition of 2 mM of a cAMP analogue, dbcAMP, to a nonagglutinating diluent failed to induce sperm agglutination. Agglutination status had no effect on sperm plasma membrane/acrosome status and mitochondrial membrane potential. In conclusion, calcium and other component(s) in the CSF of egg yolk induced head-to-head

  12. Efficacy and safety profiles of manidipine compared with amlodipine: A meta-analysis of head-to-head trials

    PubMed Central

    RICHY, FLORENT F; LAURENT, STEPHANE

    2011-01-01

    The aim of this meta-analysis was to compare the efficacy and safety profile of manidipine 20 mg with that of amlodipine 10 mg. A systematic research of quantitative data produced or published between 1995 and 2009 was performed. Head-to-head randomized controlled trials (RCTs) of 12 months minimum duration reporting comparative efficacy (changes in systolic and diastolic blood pressure) and safety (total adverse events and ankle oedema), were included. Four high-quality RCTs, accounting for 838 patients (436 received manidipine and 402 received amlodipine) were included. The effi cacy of manidipine and amlodipine was statistically equivalent: effect size for DBP =−0.08 (p = 0.22) and SBP =−0.01 (p =0.83).The global safety of manidipine was signifi cantly better than amlodipine: the relative risk (RR) for adverse event was 0.69 (0.56 – 0.85), and particularly for ankle oedema RR was 0.35 (0.22 – 0.54). Publication bias was not signifi cant and the robustness of the analyses was good. These data suggest a better efficacy/safety ratio of manidipine over amlodipine. PMID:20945994

  13. Is investigator background related to outcome in head to head trials of psychotherapy and pharmacotherapy for adult depression? A systematic review and meta-analysis

    PubMed Central

    Gentili, Claudio; Pietrini, Pietro; Cuijpers, Pim

    2017-01-01

    Background The influence of factors related to the background of investigators conducting trials comparing psychotherapy and pharmacotherapy has remained largely unstudied. Specializations emphasizing biological determinants of mental disorders, like psychiatry, might favor pharmacotherapy, while others stressing psychosocial factors, like psychology, could promote psychotherapy. Yet financial conflict of interest (COI) could be a confounding factor as authors with a medical specialization might receive more sponsoring from the pharmaceutical industry. Method We conducted a meta-analysis with subgroup and meta-regression analysis examining whether the specialization and affiliation of trial authors were associated to outcomes in the direct comparison of psychotherapy and pharmacotherapy for the acute treatment of depression. Meta-regression analysis also included trial risk of bias and author conflict of interest in relationship to the pharmaceutical industry. Results We included 45 trials. In half, the first author was psychologist. The last author was psychiatrist/MD in half of the trials, and a psychologist or statistician/other technical in the rest. Most lead authors had medical affiliations. Subgroup analysis indicated that studies with last authors statisticians favored pharmacotherapy. Univariate analysis showed a negative relationship between the presence of statisticians and outcomes favoring psychotherapy. Multivariate analysis showed that trials including authors with financial COI reported findings more favorable to pharmacotherapy. Discussion We report the first detailed overview of the background of authors conducting head to head trials for depression. Trials co-authored by statisticians appear to subtly favor pharmacotherapy. Receiving funding from the industry is more closely related to finding better outcomes for the industry’s elective treatment than are factors related to authors’ background. Limitations For a minority of authors we could

  14. The Efficacy of Natalizumab versus Fingolimod for Patients with Relapsing-Remitting Multiple Sclerosis: A Systematic Review, Indirect Evidence from Randomized Placebo-Controlled Trials and Meta-Analysis of Observational Head-to-Head Trials

    PubMed Central

    Tsivgoulis, Georgios; Katsanos, Aristeidis H.; Mavridis, Dimitris; Grigoriadis, Nikolaos; Dardiotis, Efthymios; Heliopoulos, Ioannis; Papathanasopoulos, Panagiotis; Karapanayiotides, Theodoros; Kilidireas, Constantinos; Hadjigeorgiou, Georgios M.; Voumvourakis, Konstantinos

    2016-01-01

    Background Although Fingolimod (FGD) and Natalizumab (NTZ) appear to be effective in relapsing-remitting multiple sclerosis (RRMS), they have never been directly compared in a randomized clinical trial (RCT). Methods and Findings We evaluated the comparative efficacy of FGD vs. NTZ using a meta-analytical approach. Data from placebo-controlled RCTs was used for indirect comparisons and observational data was utilized for head-to-head comparisons. We identified 3 RCTs (2498 patients) and 5 observational studies (2576 patients). NTZ was associated with a greater reduction in the 2-year annualized relapse rate (ARR; SMDindirect = -0.24;95% CI: from -0.44 to -0.04; p = 0.005) and with the probability of no disease activity at 2 years (ORindirect:1.82, 95% CI: from 1.05 to 3.15) compared to FGD, while no differences between the two therapies were found in the proportion of patients who remained relapse-free (ORindirect = 1.20;95% CI: from 0.84 to 1.71) and those with disability progression (ORindirect = 0.76;95% CI: from 0.48 to 1.21) at 2 years. In the analysis of observational data, we found no significant differences between NTZ and FGD in the 2-year ARR (SMD = -0.05; 95% CI: from -0.26 to 0.16), and 2-year disability progression (OR:1.08;95% CI: from 0.77 to 1.52). However, NTZ-treated patients were more likely to remain relapse-free at 2-years compared to FGD (OR: 2.19;95% CI: from 1.15 to 4.18; p = z0.020). Conclusions Indirect analyses of RCT data and head-to-head comparisons of observational findings indicate that NTZ may be more effective than FGD in terms of disease activity reduction in patients with RRMS. However, head-to-head RCTs are required to independently confirm this preliminary observation. PMID:27684943

  15. Head-to-head comparisons of quality of life instruments for young adult survivors of childhood cancer

    PubMed Central

    Huang, I-Chan; Quinn, Gwendolyn P.; Krull, Kevin; Eddleton, Katie Z.; Murphy, Devin C.; Shenkman, Elizabeth A.; Shearer, Patricia D.

    2011-01-01

    Purpose Few studies examine the relevance of health-related quality of life (HRQOL) instruments for young adult survivors of childhood cancer (YASCC). This study compared psychometric properties of two survivor-specific instruments, the Quality of Life-Cancer Survivor (QOL-CS) and Quality of Life in Adult Cancer Survivor (QLACS). Methods Data from 151 YASCC who enrolled in Cancer/Tumor Registries of two medical centers were used. We examined construct validity by conducting confirmatory factor analysis using indices of chi-square statistic, comparative fit index (CFI), and root mean square error of approximation (RMSEA). We examined convergent/discriminant validity by comparing Pearson’s correlation coefficients of homogeneous (e.g., physical functioning and pain) of both instruments vs. heterogeneous domains (e.g., physical and psychological functioning). We assessed known-groups validity by examining the extent to which HRQOL differed by late effects and comorbid conditions and calculated relative validity (RV) defined as contrasting F-statistics of individual domains to the domain with the lowest F-statistic. Superior known-groups validity is observed if a domain of one instrument demonstrates a higher RV than other domains of the instruments. Results YASCC data cannot replicate the constructs both instruments intend to measure, suggesting poor construct validity. Correlations of between-homogeneous and between-heterogeneous domains of both instruments were not discernible, suggesting poor convergent/discriminant validity. Both instruments were equally able to differentiate HRQOL between YASCC with and without late effects and comorbid conditions, suggesting similar known-groups validity. Conclusions Neither instrument is superior. Item response theory is suggested to select high quality items from different instruments to improve HRQOL measure for YASCC. PMID:22105163

  16. PubMed vs. HighWire Press: a head-to-head comparison of two medical literature search engines.

    PubMed

    Vanhecke, Thomas E; Barnes, Michael A; Zimmerman, Janet; Shoichet, Sandor

    2007-09-01

    PubMed and HighWire Press are both useful medical literature search engines available for free to anyone on the internet. We measured retrieval accuracy, number of results generated, retrieval speed, features and search tools on HighWire Press and PubMed using the quick search features of each. We found that using HighWire Press resulted in a higher likelihood of retrieving the desired article and higher number of search results than the same search on PubMed. PubMed was faster than HighWire Press in delivering search results regardless of search settings. There are considerable differences in search features between these two search engines.

  17. SU-E-T-38: A Head to Head Comparison of Two Commercial Phantoms Used for SRS QA

    SciTech Connect

    Sarkar, V; Huang, L; Huang, Y; Szegedi, M; Rassiah-Szegedi, P; Zhao, H; Salter, B

    2015-06-15

    Purpose: To compare and contrast two commercial SRS QA phantoms. Methods: Both phantoms were evaluated in terms of their ease of setup as well as the time required to switch inserts for different tests. They were both used to evaluate the coincidence of the radiation and laser isocenters of a linear accelerator. End-to-end dosimetric tests were also performed using both ion chambers and films along two planes through the center of the phantoms. Since one phantom allows for multiple ion chamber orientations, a test was also performed to determine the effect of having the chamber oriented along the radiation beam axis’. Results: Changing inserts took 2 minutes on average for one phantom compared to 5 minutes for the other. The laser/radiation isocenter coincidence as determined from each phantom showed a maximum difference of 0.2mm. Ion chamber results were within 0.5% of the expected values when the chamber was perpendicular to the beams but measured a 3% underdose when the chamber was along the beam direction. Gamma (2%,2mm) pass rates of corresponding films were within 1% between phantoms. Conclusion: The results of the corresponding tests run on both phantoms were comparable, showing that the phantoms were equivalent for the subset of SRS QA tests run here. However, the under dose observed when the chamber was parallel to the beam direction suggests that this configuration should be avoided.

  18. A head-to-head comparison of SCRalyze and Ledalab, two model-based methods for skin conductance analysis.

    PubMed

    Bach, Dominik R

    2014-12-01

    Model-based analysis of skin conductance responses (SCR) can furnish less noisy estimates of sympathetic arousal (SA) than operational peak scoring approaches, as shown in previous work. Here, I compare two model-based methods for analysis of evoked (stimulus-locked) SCR, implemented in two software packages, SCRalyze and Ledalab, with respect to their sensitivity in recovering SA. Four datasets are analysed to compare predictive validity, i.e. the sensitivity to distinguish pairs of SA states that are known to be different. SCRalyze was significantly better able than Ledalab to recover this known difference in four out of five tested contrasts and comparable in the remaining one. SCRalyze performed significantly better than conventional analysis in all contrasts. I conclude that the model-based method engendered in SCRalyze is currently the best available approach to provide robust and sensitive estimates of sympathetic arousal.

  19. A head-to-head comparison of SCRalyze and Ledalab, two model-based methods for skin conductance analysis

    PubMed Central

    Bach, Dominik R.

    2014-01-01

    Model-based analysis of skin conductance responses (SCR) can furnish less noisy estimates of sympathetic arousal (SA) than operational peak scoring approaches, as shown in previous work. Here, I compare two model-based methods for analysis of evoked (stimulus-locked) SCR, implemented in two software packages, SCRalyze and Ledalab, with respect to their sensitivity in recovering SA. Four datasets are analysed to compare predictive validity, i.e. the sensitivity to distinguish pairs of SA states that are known to be different. SCRalyze was significantly better able than Ledalab to recover this known difference in four out of five tested contrasts and comparable in the remaining one. SCRalyze performed significantly better than conventional analysis in all contrasts. I conclude that the model-based method engendered in SCRalyze is currently the best available approach to provide robust and sensitive estimates of sympathetic arousal. PMID:25148785

  20. Head-to-Head Comparison of Soluble vs. Qβ VLP Circumsporozoite Protein Vaccines Reveals Selective Enhancement of NANP Repeat Responses

    PubMed Central

    Schwenk, Robert; DeBot, Margot; Saudan, Philippe; Dutta, Sheetij

    2015-01-01

    Circumsporozoite protein (CSP) of Plasmodium falciparum is a promising malaria vaccine target. RTS,S, the most advanced malaria vaccine candidate consists of the central NANP repeat and carboxy-terminal region of CSP displayed on a hepatitis B virus-like particle (VLP). To build upon the success of RTS,S, we produced a near full-length Plasmodium falciparum CSP that also includes the conserved amino-terminal region of CSP. We recently showed that this soluble CSP, combined with a synthetic Toll-like-receptor-4 (TLR4) agonist in stable oil-in-water emulsion (GLA/SE), induces a potent and protective immune response in mice against transgenic parasite challenge. Here we have investigated whether the immunogenicity of soluble CSP could be further augmented by presentation on a VLP. Bacteriophage Qβ VLPs can be readily produced in E.coli, they have a diameter of 25 nm and contain packaged E. coli RNA which serves as a built in adjuvant through the activation of TLR7/8. CSP was chemically conjugated to Qβ and the CSP-Qβ vaccine immunogenicity and efficacy were compared to adjuvanted soluble CSP in the C57Bl/6 mouse model. When formulated with adjuvants lacking a TLR4 agonist (Alum, SE and Montanide) the Qβ-CSP induced higher anti-NANP repeat titers, higher levels of cytophilic IgG2b/c antibodies and a trend towards higher protection against transgenic parasite challenge as compared to soluble CSP formulated in the same adjuvant. The VLP and soluble CSP immunogenicity difference was most pronounced at low antigen dose, and within the CSP molecule, the titers against the NANP repeats were preferentially enhanced by Qβ presentation. While a TLR4 agonist enhanced the immunogenicity of soluble CSP to levels comparable to the VLP vaccine, the TLR4 agonist did not further improve the immunogenicity of the Qβ-CSP vaccine. The data presented here pave the way for further improvement in the Qβ conjugation chemistry and evaluation of both the Qβ-CSP and soluble CSP vaccines in the non-human primate model. PMID:26571021

  1. Charge compensation of head-to-head and tail-to-tail domain walls in barium titanate and its influence on conductivity

    SciTech Connect

    Zuo, Yinan; Genenko, Yuri A.; Xu, Bai-Xiang

    2014-07-28

    The effect of the polarization charge compensation by ionic and electronic space charges on domain properties in ferroelectrics with semiconducting features is considered, in particular, the conductivity of head-to-head and tail-to-tail domain walls is studied. It is shown that the domain wall conductivity that is enhanced by electrons or holes depends on the configuration and the types of domains as well as on the energy levels and concentrations of the defects involved. Phase field simulation results are used to explain recent equivocal experimental results on conductivity of charged domain walls in different ferroelectrics.

  2. Mechanostereoselective One-Pot Synthesis of Functionalized Head-to-Head Cyclodextrin [3]Rotaxanes and Their Application as Magnetic Resonance Imaging Contrast Agents.

    PubMed

    Fredy, Jean Wilfried; Scelle, Jérémy; Ramniceanu, Gregory; Doan, Bich-Thuy; Bonnet, Célia S; Tóth, Éva; Ménand, Mickaël; Sollogoub, Matthieu; Vives, Guillaume; Hasenknopf, Bernold

    2017-02-21

    A versatile, five-component, one-pot synthesis of cyclodextrin (CD) [3]rotaxanes using copper-catalyzed azide-alkyne cycloaddition has been developed. Head-to-head [3]rotaxanes of α-CD selectively functionalized by one or two gadolinium 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid monoamide complexes were obtained mechanostereoselectively. The magnetic resonance imaging efficiency, expressed by the longitudinal proton relaxivity of the rotaxanes, was significantly improved as compared to the functionalized CD. In vitro and in vivo preclinical studies showed a higher contrast and retention in the kidney than gadolinium 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid complex, demonstrating the potential of these rotaxanes as MRI contrast agent.

  3. Two-dimensional electron gases at head-to-head and tail-to-tail domain walls in ferroelectric thin films

    NASA Astrophysics Data System (ADS)

    García-Fernández, Pablo; Íñiguez, Jorge; Junquera, Javier

    Symmetry breaking at ferroelectric domain walls gives rise to new physical properties, offering the opportunity to use the domain walls themselves as a functional separate object in a device. One example is the appearance of an enhanced conductivity at the boundaries between ferroelectric domains in oxides. A realistic first-principles simulation of the domains walls is limited to highly-symmetric cleanly-cut walls in order to keep the number of atoms in the simulation box small. Here we use a recently developed second-principles method that treats all the lattice degrees of freedom and the relevant electronic ones on the same foot with high accuracy at a modest computational cost. We apply it to the demading physical problem of head-to-head (HH) and tail-to-tail (TT) domain walls in ferroelectric PbTiO3 thin films. These interfaces present a large and unfavourable electrostatic energy due to the polarization-induced bound charge at the domain wall. An accurate simulation should capture eventual charge transfers between the walls, and the concomitant electron-lattice coupling. We show how the polarization discontinuity in HH and TT domain walls in PbTiO3 thin films can be effectively screened by the formation of two-dimensional electron gases of electrons and holes. Finantial support from MINECO Grant No. FIS2012-37549-C05-04.

  4. Functional outcomes from a head-to-head, randomized, double-blind trial of lisdexamfetamine dimesylate and atomoxetine in children and adolescents with attention-deficit/hyperactivity disorder and an inadequate response to methylphenidate.

    PubMed

    Nagy, Peter; Häge, Alexander; Coghill, David R; Caballero, Beatriz; Adeyi, Ben; Anderson, Colleen S; Sikirica, Vanja; Cardo, Esther

    2016-02-01

    Attention-deficit/hyperactivity disorder (ADHD) is associated with functional impairments in multiple domains of patients' lives. A secondary objective of this randomized, active-controlled, head-to-head, double-blind, dose-optimized clinical trial was to compare the effects of lisdexamfetamine dimesylate (LDX) and atomoxetine (ATX) on functional impairment in children and adolescents with ADHD. Patients aged 6-17 years with an ADHD Rating Scale IV total score ≥ 28 and an inadequate response to methylphenidate treatment (judged by investigators) were randomized (1:1) to once-daily LDX or ATX for 9 weeks. Parents/guardians completed the Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P) at baseline and at week 9 or early termination. p values were nominal and not corrected for multiple comparisons. Of 267 randomized patients, 200 completed the study (LDX 99, ATX 101). At baseline, mean WFIRS-P total score in the LDX group was 0.95 [standard deviation (SD) 0.474; 95% confidence interval (CI) 0.87, 1.03] and in the ATX group was 0.91 (0.513; 0.82, 1.00). Scores in all WFIRS-P domains improved from baseline to endpoint in both groups, with least-squares mean changes in total score of -0.35 (95% CI -0.42, -0.29) for LDX and -0.27 (-0.33, -0.20) for ATX. The difference between LDX and ATX was statistically significant (p < 0.05) for the Learning and School (effect size of LDX vs ATX, 0.43) and Social Activities (0.34) domains and for total score (0.27). Both treatments reduced functional impairment in children and adolescents with ADHD; LDX was statistically significantly more effective than ATX in two of six domains and in total score.

  5. Percutaneous Transthoracic Lung Biopsy: Comparison Between C-Arm Cone-Beam CT and Conventional CT Guidance

    PubMed Central

    Cheng, Yun-Chung; Tsai, Sheng-Heng; Cheng, Yuchi; Chen, Jeon-Hor; Chai, Jyh-Wen; Chen, Clayton Chi-Chang

    2015-01-01

    BACKGROUND: C-arm cone-beam computed tomography (CBCT) is a comparatively novel modality for guiding percutaneous transthoracic lung biopsies (PTLBs), and despite its potential advantages over conventional computed tomography (CCT), a head-to-head comparison of the two techniques has yet to be reported in the literature. This study aims to evaluate the diagnostic value and safety of CBCT-guided PTLB compared to CCT-guided biopsy, with cases performed in a single hospital. METHODS: A total of 104 PTLB patients were retrospectively analyzed in this study. 35 PTLBs were performed under CBCT guidance, and 69 PTLBs were performed under CCT guidance. Diagnostic accuracy, sensitivity, and specificity for malignancy as well as procedure time, radiation dose of patients, and complication rate in the two groups were compared. RESULTS: Total procedure time was significantly lower in the CBCT group (32 ± 11 minutes) compared to the CCT group (38 ± 9.7 minutes; P = .009), especially among patients ≥ 70 years of age (CBCT: 33 ± 12 minutes, CCT: 42 ± 13, P = .022). For lesions in the lower lobes, the CBCT-guided group received significantly reduced effective radiation dose (2.9 ± 1.6 mSv) than CCT-guided patients (3.7 ± 0.80; P = .042). Diagnostic accuracy, sensitivity, and specificity for malignancy were comparable between the two groups, as were post-biopsy complication rates. CONCLUSION: CBCT guidance significantly reduces the procedure time and radiation exposure for PTLBs compared with CCT, and should be considered in clinical settings that may be difficult or time-consuming to perform under CCT. PMID:26310371

  6. Relative biological effectiveness of 144 keV neutrons in producing dicentric chromosomes in human lymphocytes compared with 60Co gamma rays under head-to-head conditions.

    PubMed

    Schmid, E; Regulla, D; Guldbakke, S; Schlegel, D; Roos, M

    2002-04-01

    The RBE for neutrons was assessed in a head-to-head experiment in which cultures of lymphocytes from the same male donor were irradiated simultaneously with 144 keV neutrons and with 60Co gamma rays as the reference radiation and evaluated using matched time, culture conditions, and the end point of chromosomal aberrations to avoid potential confounding factors that would influence the outcome of the experiment. In addition, the irradiation time was held constant at 2 h for the high-dose groups for both radiation types, which resulted in rather low dose rates. For the induction of dicentric chromosomes, the exposure to the 144 keV neutrons was found to be almost equally as effective (yield coefficient alpha(dic) = 0.786 +/- 0.066 dicentrics per cell per gray) as that found previously for irradiation with monoenergetic neutrons at 565 keV (alpha(dic) = 0.813 +/- 0.052 dicentrics per cell per gray) under comparable exposure and culture conditions (Radiat. Res. 154, 307-312, 2000). However, the values of the maximum low-dose RBE (RBE(m)) relative to 60Co gamma rays that were determined in the present and previous studies show an insignificant but conspicuous difference: 57.0 +/- 18.8 and 76.0 +/- 29.5, respectively. This difference is mainly due to the difference in the alpha(dic) value of the 60Co gamma rays, the reference radiation, which was 0.0138 +/- 0.0044 Gy(-1) in the present study and 0.0107 +/- 0.0041 Gy(-1) in the previous study. In the present experiment, irradiations with 144 keV neutrons and 60Co gamma rays were both performed at 21 degrees C, while in the earlier experiment irradiations with 565 keV neutrons were performed at 21 degrees C and the corresponding reference irradiation with gamma rays was performed at 37 degrees C. However, the temperature difference between 21 degrees C and 37 degrees C has a minor influence on the yield of chromosomal alterations and hence RBE values. The large cubic PMMA phantom that was used for the gamma irradiations

  7. Accuracy of two continuous glucose monitoring systems: a head-to-head comparison under clinical research centre and daily life conditions

    PubMed Central

    Kropff, J; Bruttomesso, D; Doll, W; Farret, A; Galasso, S; Luijf, Y M; Mader, J K; Place, J; Boscari, F; Pieber, T R; Renard, E; DeVries, J H

    2015-01-01

    Aims To assess the accuracy and reliability of the two most widely used continuous glucose monitoring (CGM) systems. Methods We studied the Dexcom®G4 Platinum (DG4P; Dexcom, San Diego, CA, USA) and Medtronic Paradigm Veo Enlite system (ENL; Medtronic, Northridge, CA, USA) CGM systems, in 24 patients with type 1 diabetes. The CGM systems were tested during 6-day home use and a nested 6-h clinical research centre (CRC) visit. During the CRC visit, frequent venous blood glucose samples were used as reference while patients received a meal with an increased insulin bolus to induce an aggravated postprandial glucose nadir. At home, patients performed at least six reference capillary blood measurements per day. A Wilcoxon signed-rank test was performed using all data points ≥15 min apart. Results The overall mean absolute relative difference (MARD) value [standard deviation (s.d.)] measured at the CRC was 13.6 (11.0)% for the DG4P and 16.6 (13.5)% for the ENL [p < 0.0002, confidence interval of difference (CI Δ) 1.7–4.3%, n = 530]. The overall MARD assessed at home was 12.2 (12.0)% for the DG4P and 19.9 (20.5)% for the ENL (p < 0.0001, CI Δ = 5.8–8.7%, n = 839). During the CRC visit, the MARD in the hypoglycaemic range [≤3.9 mmol/l (70 mg/dl)], was 17.6 (12.2)% for the DG4P and 24.6 (18.8)% for the ENL (p = 0.005, CI Δ 3.1–10.7%, n = 117). Both sensors showed higher MARD values during hypoglycaemia than during euglycaemia [3.9–10 mmol/l (70–180 mg/dl)]: for the DG4P 17.6 versus 13.0% and for the ENL 24.6 versus 14.2%. Conclusions During circumstances of intended use, including both a CRC and home phase, the ENL was noticeably less accurate than the DG4P sensor. Both sensors showed lower accuracy in the hypoglycaemic range. The DG4P was less affected by this negative effect of hypoglycaemia on sensor accuracy than was the ENL. PMID:25132320

  8. Head to Head Comparison of Short-Term Treatment with the NAD+ Precursor Nicotinamide Mononucleotide (NMN) and 6 Weeks of Exercise in Obese Female Mice

    PubMed Central

    Uddin, Golam M.; Youngson, Neil A.; Sinclair, David A.; Morris, Margaret J.

    2016-01-01

    Obesity is well known to be a major cause of several chronic metabolic diseases, which can be partially counteracted by exercise. This is due, in part, to an upregulation of mitochondrial activity through increased nicotinamide adenine dinucleotide (NAD+). Recent studies have shown that NAD+ levels can be increased by using the NAD+ precursor, nicotinamide mononucleotide (NMN) leading to the suggestion that NMN could be a useful intervention in diet related metabolic disorders. In this study we compared the metabolic, and especially mitochondrial-associated, effects of exercise and NMN in ameliorating the consequences of high-fat diet (HFD) induced obesity in mice. Sixty female 5 week old C57BL6/J mice were allocated across five groups: Chow sedentary: CS; Chow exercise: CEX; HFD sedentary: HS; HFD NMN: HNMN; HFD exercise: HEX (12/group). After 6 weeks of diet, exercise groups underwent treadmill exercise (15 m/min for 45 min), 6 days per week for 6 weeks. NMN or vehicle (500 mg/kg body weight) was injected (i.p.) daily for the last 17 days. No significant alteration in body weight was observed in response to exercise or NMN. The HFD significantly altered adiposity, glucose tolerance, plasma insulin, NADH levels and citrate synthase activity in muscle and liver. HEX and HNMN groups both showed significantly improved glucose tolerance compared to the HS group. NAD+ levels were increased significantly both in muscle and liver by NMN whereas exercise increased NAD+ only in muscle. Both NMN and exercise ameliorated the HFD-induced reduction in liver citrate synthase activity. However, exercise, but not NMN, ameliorated citrate synthase activity in muscle. Overall these data suggest that while exercise and NMN-supplementation can induce similar reversal of the glucose intolerance induced by obesity, they are associated with tissue-specific effects and differential alterations to mitochondrial function in muscle and liver. PMID:27594836

  9. Recruiting Pregnant Patients for Survey Research: A Head to Head Comparison of Social Media-Based Versus Clinic-Based Approaches

    PubMed Central

    Haefner, Jessica K; Kolenic, Giselle E; Chang, Tammy; Davis, Matthew M; Moniz, Michelle H

    2016-01-01

    Background Recruiting a diverse sample of pregnant women for clinical research is a challenging but crucial task for improving obstetric services and maternal and child health outcomes. Objective To compare the feasibility and cost of recruiting pregnant women for survey research using social media-based and clinic-based approaches. Methods Advertisements were used to recruit pregnant women from the social media website Facebook. In-person methods were used to recruit pregnant women from the outpatient clinic of a large, tertiary care center. In both approaches, potential respondents were invited to participate in a 15-minute Web-based survey. Each recruitment method was monitored for 1 month. Using bivariate statistics, we compared the number, demographic characteristics, and health characteristics of women recruited and the cost per completed survey for each recruitment method. Results The social media-based approach recruited 1178 women and the clinic-based approach recruited 219 women. A higher proportion of subjects recruited through social media identified as African American (29.4%, 207/705 vs 11.2%, 20/179), reported household incomes

  10. A head-to-head comparison of eneamide and epoxyamide inhibitors of glucosamine-6-phosphate synthase from the dapdiamide biosynthetic pathway.

    PubMed

    Hollenhorst, Marie A; Ntai, Ioanna; Badet, Bernard; Kelleher, Neil L; Walsh, Christopher T

    2011-05-17

    The dapdiamides make up a family of antibiotics that have been presumed to be cleaved in the target cell to enzyme-inhibitory N-acyl-2,3-diaminopropionate (DAP) warheads containing two alternative electrophilic moieties. Our prior biosynthetic studies revealed that an eneamide warhead is made first and converted to an epoxyamide via a three-enzyme branch pathway. Here we provide a rationale for this logic. We report that the R,R-epoxyamide warhead is a more efficient covalent inactivator of glucosamine-6-phosphate synthase by 1 order of magnitude versus the eneamide, and this difference correlates with a >10-fold difference in antibiotic activity for the corresponding acyl-DAP dipeptides.

  11. Accuracy, Precision, and Reproducibility of Four T1 Mapping Sequences: A Head-to-Head Comparison of MOLLI, ShMOLLI, SASHA, and SAPPHIRE

    PubMed Central

    Roujol, Sébastien; Weingärtner, Sebastian; Foppa, Murilo; Chow, Kelvin; Kawaji, Keigo; Ngo, Long H.; Kellman, Peter; Manning, Warren J.; Thompson, Richard B.

    2014-01-01

    Purpose To compare accuracy, precision, and reproducibility of four commonly used myocardial T1 mapping sequences: modified Look-Locker inversion recovery (MOLLI), shortened MOLLI (ShMOLLI), saturation recovery single-shot acquisition (SASHA), and saturation pulse prepared heart rate independent inversion recovery (SAPPHIRE). Materials and Methods This HIPAA-compliant study was approved by the institutional review board. All subjects provided written informed consent. Accuracy, precision, and reproducibility of the four T1 mapping sequences were first compared in phantom experiments. In vivo analysis was performed in seven healthy subjects (mean age ± standard deviation, 38 years ± 19; four men, three women) who were imaged twice on two separate days. In vivo reproducibility of native T1 mapping and extracellular volume (ECV) were measured. Differences between the sequences were assessed by using Kruskal-Wallis and Wilcoxon rank sum tests (phantom data) and mixed-effect models (in vivo data). Results T1 mapping accuracy in phantoms was lower with ShMOLLI (62 msec) and MOLLI (44 msec) than with SASHA (13 msec; P < .05) and SAPPHIRE (12 msec; P < .05). MOLLI had similar precision to ShMOLLI (4.0 msec vs 5.6 msec; P = .07) but higher precision than SAPPHIRE (6.8 msec; P = .002) and SASHA (8.7 msec; P < .001). All sequences had similar reproducibility in phantoms (P = .1). The four sequences had similar in vivo reproducibility for native T1 mapping (∼25–50 msec; P > .05) and ECV quantification (∼0.01–0.02; P > .05). Conclusion SASHA and SAPPHIRE yield higher accuracy, lower precision, and similar reproducibility compared with MOLLI and ShMOLLI for T1 measurement. Different sequences yield different ECV values; however, all sequences have similar reproducibility for ECV quantification. © RSNA, 2014 Online supplemental material is available for this article. PMID:24702727

  12. A Systematic Review of Head-to-Head Comparison Studies of the Roland-Morris and Oswestry Measures' Abilities to Assess Change.

    PubMed

    Newman, Anastasia N L; Stratford, Paul W; Letts, Lori; Spadoni, Gregory

    2013-01-01

    Objectif : Déterminer si la sensibilité au changement des résultats au questionnaire Roland-Morris (Roland-Morris Questionnaire, RMQ) et au questionnaire d'incapacité d'Oswestry (Oswestry Disability Index, ODI) diffèrent lorsqu'on les applique aux patients qui souffrent de lombalgie. Comme objectif secondaire, réaliser une analyse critique de la rigueur méthodologique des études comparatives directes sélectionnées. Méthode : Une revue systématique de cinq bases de données en ligne a été réalisée pour rechercher des études comparatives directes du RMQ et de l'ODI qui évaluaient la sensibilité au changement de ces deux mesures. Les études étaient retenues si elles satisfaisaient à un ensemble de critères d'inclusion préétabli. Un formulaire de critères de qualité nouvellement élaboré a été utilisé pour évaluer la rigueur méthodologique des études comparatives directes. Résultats : Neuf articles satisfaisaient aux critères d'inclusion. Bien que pour deux études, on ait constaté une différence statistique appréciable favorable au RQM, il n'y avait aucun avantage apparent commun pour une mesure plutôt que pour l'autre. Les lacunes méthodologiques fréquentes étaient notamment l'absence de calcul formel de la taille de l'échantillon, l'absence de critère pour la comparaison des mesures et le fait qu'il n'y avait aucune norme de référence indépendante. Conclusion : Il n'y a aucun élément probant commun permettant de privilégier une mesure plutôt qu'une autre. Plusieurs études comportaient des lacunes sur le plan méthodologique.

  13. Is acculturation unidimensional or bidimensional? A head-to-head comparison in the prediction of personality, self-identity, and adjustment.

    PubMed

    Ryder, A G; Alden, L E; Paulhus, D L

    2000-07-01

    The unidimensional model of acculturation posits that heritage and mainstream culture identifications have a strong inverse relation, whereas the bidimensional model posits that the 2 identifications are independent. The authors compared these models in 3 samples of ethnic Chinese (ns = 164, 150, and 204), 1 sample of non-Chinese East Asians (n = 70), and one diverse group of acculturating individuals (n = 140). Although the unidimensional measure showed a coherent pattern of external correlates, the bidimensional measure revealed independent dimensions corresponding to heritage and mainstream culture identification. These dimensions displayed patterns of noninverse correlations with personality, self-identity, and psychosocial adjustment. The authors conclude that the bidimensional model is a more valid and useful operationalization of acculturation.

  14. Comparison of cerebral blood flow data obtained by computed tomography (CT) perfusion with that obtained by xenon CT using 320-row CT.

    PubMed

    Takahashi, Satoshi; Tanizaki, Yoshio; Kimura, Hiroaki; Akaji, Kazunori; Kano, Tadashige; Suzuki, Kentaro; Takayama, Youhei; Kanzawa, Takao; Shidoh, Satoka; Nakazawa, Masaki; Yoshida, Kazunari; Mihara, Ban

    2015-03-01

    Cerebral blood flow (CBF) data obtained by computed tomography perfusion (CTP) imaging have been shown to be qualitative data rather than quantitative, in contrast with data obtained by other imaging methods, such as xenon CT (XeCT) imaging. Thus, interpatient comparisons of CBF values themselves obtained by CTP may be inaccurate. In this study, we have compared CBF ratios as well as CBF values obtained from CTP-CBF data to those obtained from XeCT-CBF data for the same patients to determine CTP-CBF parameters that can be used for interpatient comparisons. The data used in the present study were obtained as volume data using 320-row CT. The volume data were applied to an automated region of interest-determining software (3DSRT, version 3.5.2 ) and converted to 59 slices of 2 mm interval standardized images. In the present study, we reviewed 10 patients with occlusive cerebrovascular diseases (CVDs) undergoing both CTP and XeCT in the same period. Our study shows that ratios of CBF measurements, such as hemodynamic stress distribution (perforator-to-cortical flow ratio of middle cerebral artery [MCA] region) or the left/right ratio for the region of the MCA, calculated using CTP data have been shown to correlate well with the same ratios calculated using XeCT data. These results suggest that such CBF ratios could be useful for generating interpatient comparisons of CTP-CBF data obtained by 320-row CT among patients with occlusive CVD.

  15. Primary hyperaldosteronism: comparison of CT, adrenal venography, and venous sampling

    SciTech Connect

    Geisinger, M.A.; Zelch, M.G.; Bravo, E.L.; Risius, B.F.; O'Donovan, P.B.; Borkowski, G.P.

    1983-08-01

    Twenty-nine patients with primary hyperaldosteronism were evaluated with computed tomography (CT), adrenal venous sampling, and adrenal venography. Twenty-three patients had aldosteronomas and six had bilateral adrenocortical hyperplasia. Sixteen (70%) of the adenomas were accurately located by CT. All nodules of 1.5 cm or larger diameter and 50% of nodules 1.0 to 1.4 cm in diameter were demonstrated. Nodules of less than 1.0 cm in diameter generally were not detected. High-resolution CT appeared more sensitive than standard CT (75% vs 58%). Adrenal venous sampling for aldosterone assay was the most sensitive of the three methods, localizing 22 (96%) of the 23 adenomas. Eighteen (78%) of the adenomas were identified by adrenal venography, although two patients with bilateral cortical hyperplasia were mistakenly diagnosed as having a small adenoma. No such false-positive studies were encountered with CT or adrenal venous sampling.

  16. Comparison of CT and MR-CT Fusion for Prostate Post-Implant Dosimetry

    SciTech Connect

    Maletz, Kristina L.; Ennis, Ronald D.; Ostenson, Jason; Pevsner, Alexander; Kagen, Alexander; Wernick, Iddo

    2012-04-01

    Purpose: The use of T2 MR for postimplant dosimetry (PID) after prostate brachytherapy allows more anatomically accurate and precise contouring but does not readily permit seed identification. We developed a reproducible technique for performing MR-CT fusion and compared the resulting dosimetry to standard CT-based PID. Methods and Materials: CT and T1-weighted MR images for 45 patients were fused and aligned based on seed distribution. The T2-weighted MR image was then fused to the aligned T1. Reproducibility of the fusion technique was tested by inter- and intraobserver variability for 13 patients. Dosimetry was computed for the prostate as a whole and for the prostate divided into anterior and posterior sectors of the base, mid-prostate, and apex. Results: Inter- and intraobserver variability for the fusion technique showed less than 1% variation in D90. MR-CT fusion D90 and CT D90 were nearly equivalent for the whole prostate, but differed depending on the identification of superior extent of the base (p = 0.007) and on MR/CT prostate volume ratio (p = 0.03). Sector analysis showed a decrease in MR-CT fusion D90 in the anterior base (ratio 0.93 {+-}0.25, p < 0.05) and an increase in MR-CT fusion D90 in the apex (p < 0.05). The volume of extraprostatic tissue encompassed by the V100 is greater on MR than CT. Factors associated with this difference are the MR/CT volume ratio (p < 0.001) and the difference in identification of the inferior extent of the apex (p = 0.03). Conclusions: We developed a reproducible MR-CT fusion technique that allows MR-based dosimetry. Comparing the resulting postimplant dosimetry with standard CT dosimetry shows several differences, including adequacy of coverage of the base and conformity of the dosimetry around the apex. Given the advantage of MR-based tissue definition, further study of MR-based dosimetry is warranted.

  17. The specific isolation of complete 5S rDNA units from chromosome 1A of hexaploid, tetraploid, and diploid wheat species using PCR with head-to-head oriented primers.

    PubMed

    Van Campenhout, S; Stappen, J V; Volckaert, G

    2001-08-01

    The presence of 5S rDNA units on chromosome 1A of Triticum aestivum was shown by the development of a specific PCR test, using head-to-head oriented primers. This primer set allowed the amplification of complete 5S DNA units and was used to isolate SS-Rrna-A1 sequences from polyploid and diploid wheat species. Multiple-alignment and parsimony analyses of the 132 sequences divided the sequences into four types. The isolates from T. aestivum and the tetraploid species (T. dicoccoides, T. dicoccum, T durum, T. araraticum, and T timopheevi) were all of one type, which was shown to be closely related to the type mainly characteristic for T. urartu. The other two types were isolated exclusively from the diploid species T. monococcum, T aegilopoides, T. thaoudar, and T. sinskajae and the hexaploid species T. zhukovski. Triticum monococcum was the only species for which representatives of each of the four sequence types were found to be present. Further, we discuss the possible multicluster arrangement of the 5S-Rrna-A1 array.

  18. Comparison of CT scanning and radionuclide imaging in liver disease

    SciTech Connect

    Friedman, M.L.; Esposito, F.S.

    1980-01-01

    Early experience with body CT suggested its usefulness in many diagnostic problems; jaundice, renal and pancreatic masses, and in the evaluation of relatively inaccessible parts of the body, such as the retroperitineum, mediastinum, and pelvis. Investigation of hepatic disease by CT was not unexpectedly compared to radionuclide liver scanning, the major preexisting modality for imaging the liver. In the evaluation of the jaundiced patient, CT rapidly assumed a major role, providing more specific information about the liver than the RN liver scan, as well as demonstrating adjacent organs. CT differentiate obstructive from non-obstructive jaundice. With respect to mass lesions of the liver, the RN liver scan is more sensitive than CT but less specific. The abnormalities on an isotope image of the liver consist of normal variants in configuration, extrinsic compression by adjacent structures, cysts, hemangiomata, abscesses, and neoplasms. These suspected lesions may then be better delineated by the CT image, and a more precise diagnosis made. The physiologic information provided by the RN liver scan is an added facet which is helpful in the patient with diffuse hepatic disease. The CT image will be normal in many of these patients, however, hemochromatosis and fatty infiltration lend themselves especially to density evaluation by CT. The evaluation of lymphoma is more thorough with CT. Structures other than the liver, such as lymph nodes, are visualized. Gallium, however, provides additional isotopic information in patients with lymphoma, and in addition, is known to be useful in the investigation of a febrile patient with an abscess. Newer isotopic agents expand hepatic imaging in other directions, visualizing the biliary tree and evaluating the jaundiced patient.

  19. Cone Beam CT vs. Fan Beam CT: A Comparison of Image Quality and Dose Delivered Between Two Differing CT Imaging Modalities.

    PubMed

    Lechuga, Lawrence; Weidlich, Georg A

    2016-09-12

    A comparison of image quality and dose delivered between two differing computed tomography (CT) imaging modalities-fan beam and cone beam-was performed. A literature review of quantitative analyses for various image quality aspects such as uniformity, signal-to-noise ratio, artifact presence, spatial resolution, modulation transfer function (MTF), and low contrast resolution was generated. With these aspects quantified, cone beam computed tomography (CBCT) shows a superior spatial resolution to that of fan beam, while fan beam shows a greater ability to produce clear and anatomically correct images with better soft tissue differentiation. The results indicate that fan beam CT produces superior images to that of on-board imaging (OBI) cone beam CT systems, while providing a considerably less dose to the patient.

  20. Cone Beam CT vs. Fan Beam CT: A Comparison of Image Quality and Dose Delivered Between Two Differing CT Imaging Modalities

    PubMed Central

    Weidlich, Georg A.

    2016-01-01

    A comparison of image quality and dose delivered between two differing computed tomography (CT) imaging modalities—fan beam and cone beam—was performed. A literature review of quantitative analyses for various image quality aspects such as uniformity, signal-to-noise ratio, artifact presence, spatial resolution, modulation transfer function (MTF), and low contrast resolution was generated. With these aspects quantified, cone beam computed tomography (CBCT) shows a superior spatial resolution to that of fan beam, while fan beam shows a greater ability to produce clear and anatomically correct images with better soft tissue differentiation. The results indicate that fan beam CT produces superior images to that of on-board imaging (OBI) cone beam CT systems, while providing a considerably less dose to the patient. PMID:27752404

  1. Follow-up of Wilms tumor: comparison of CT with other imaging procedures

    SciTech Connect

    Brasch, R.C.; Randel, S.B.; Gould, R.G.

    1981-11-01

    In a retrospective review, computed tomography (CT) was compared to a ''routine'' combination of other diagnostic imaging procedures used for follow-up evaluations of 13 children being treated for Wilms tumor. The examined variables were diagnostic accuracy, expense, and duration of examination. Results from 13 patients indicated that CT most accurately answers diagnostic queries pertinent to follow-up evaluation of Wilms tumors: the presence and extent of bilateral renal tumors, local recurrence, contralateral renal hypertrophy, and metastasis to liver or lungs. For diagnosing pulmonary metastases, CT was superior to conventional chest radiography both in sensitivity (4/4 vs. 2/4) and specificity (9/9 vs. 6/9). In depiction of liver metastases, CT (3/3) was superior to liver scintigraphy (2/3). The extent of bilateral Wilms tumors was better defined by CT than by urography. In no instances were the alternative diagnostic imaging studies found to be more accurate than CT for the detection of recurrent tumor. Average cost for a CT examination ($344) is considerably less than the cost for a routine combination of the other imaging studies ($594). Examination time and diagnostic radiation doses are also reduced using CT. Pending larger comparison studies, CT is recommended as the primary diagnostic method for follow-up evaluation of patients with Wilms tumor.

  2. ASSESSMENT OF EFFECTIVE DOSE FROM CONE BEAM CT IMAGING IN SPECT/CT EXAMINATION IN COMPARISON WITH OTHER MODALITIES.

    PubMed

    Tonkopi, Elena; Ross, Andrew A

    2016-12-01

    The aim of this study was to assess radiation dose from the cone beam computed tomography (CBCT) component of single photon emission tomography/computed tomography (SPECT/CT) examinations and to compare it with the radiopharmaceutical related dose as well as dose from multidetector computed tomography (MDCT). Effective dose (ED) from computed tomography (CT) was estimated using dose-length product values and anatomy-specific conversion factors. The contribution from the SPECT component was evaluated using ED per unit administered activity for the radiopharmaceuticals listed in the International Commission on Radiological Protection Publications 80 and 106. With the exception of cardiac studies (0.11 mSv), the CBCT dose (3.96-6.04 mSv) was similar to that from the radiopharmaceutical accounting for 29-56 % of the total ED from the examination. In comparison with MDCT examinations, the CBCT dose was 48 and 42 % lower for abdomen/pelvis and chest/abdomen/pelvis scans, respectively, while in the chest the CBCT scan resulted in higher dose (23 %). Radiation dose from the CT component should be taken into consideration when evaluating total SPECT/CT patient dose.

  3. Comparison of X-ray film and photographic paper in recording CT images.

    PubMed

    Stephenson, T F; Lincoln, A J; Mehnert, P J; Paul, G J

    1984-12-01

    Because of a potential film cost savings of approximately 35% using photographic print paper instead of X-ray film in recording CT images, a comparison was undertaken of these hard copy recording methods. One hundred consecutive CT examinations were reviewed on the scanner display console and recorded on X-ray film and photographic print paper using a multi-imager camera. Hard copy images were compared for diagnostic adequacy. X-ray film adequately recorded the pathology in all cases. Photographic paper adequately recorded the pathology in 97% of cases. In 26% of cases X-ray film was felt to better display the CT diagnosis whereas in 2% of cases photographic paper better displayed the CT diagnosis. Test phantom scans recorded on both media showed no observable difference in spatial or contrast resolution.

  4. Comparison of stroke infarction between CT perfusion and diffusion weighted imaging: preliminary results

    NASA Astrophysics Data System (ADS)

    Abd. Rahni, Ashrani Aizzuddin; Arka, Israna Hossain; Chellappan, Kalaivani; Mukari, Shahizon Azura; Law, Zhe Kang; Sahathevan, Ramesh

    2016-03-01

    In this paper we present preliminary results of comparison of automatic segmentations of the infarct core, between that obtained from CT perfusion (based on time to peak parameter) and diffusion weighted imaging (DWI). For each patient, the two imaging volumes were automatically co-registered to a common frame of reference based on an acquired CT angiography image. The accuracy of image registration is measured by the overlap of the segmented brain from both images (CT perfusion and DWI), measured within their common field of view. Due to the limitations of the study, DWI was acquired as a follow up scan up to a week after initial CT based imaging. However, we found significant overlap of the segmented brain (Jaccard indices of approximately 0.8) and the percentage of infarcted brain tissue from the two modalities were still fairly highly correlated (correlation coefficient of approximately 0.9). The results are promising with more data needed in future for clinical inference.

  5. Comparison of SPECT/CT, MRI and CT in diagnosis of skull base bone invasion in nasopharyngeal carcinoma.

    PubMed

    Zhang, Shu-xu; Han, Peng-hui; Zhang, Guo-qian; Wang, Rui-hao; Ge, Yong-bin; Ren, Zhi-gang; Li, Jian-sheng; Fu, Wen-hai

    2014-01-01

    Early detection of skull base invasion in nasopharyngeal carcinoma (NPC) is crucial for correct staging, assessing treatment response and contouring the tumor target in radiotherapy planning, as well as improving the patient's prognosis. To compare the diagnostic efficacy of single photon emission computed tomography/computed tomography (SPECT/CT) imaging, magnetic resonance imaging (MRI) and computed tomography (CT) for the detection of skull base invasion in NPC. Sixty untreated patients with histologically proven NPC underwent SPECT/CT imaging, contrast-enhanced MRI and CT. Of the 60 patients, 30 had skull base invasion confirmed by the final results of contrast-enhanced MRI, CT and six-month follow-up imaging (MRI and CT). The diagnostic efficacy of the three imaging modalities in detecting skull base invasion was evaluated. The rates of positive findings of skull base invasion for SPECT/CT, MRI and CT were 53.3%, 48.3% and 33.3%, respectively. The sensitivity, specificity and accuracy were 93.3%, 86.7% and 90.0% for SPECT/CT fusion imaging, 96.7%, 100.0% and 98.3% for contrast-enhanced MRI, and 66.7%, 100.0% and 83.3% for contrast-enhanced CT. MRI showed the best performance for the diagnosis of skull base invasion in nasopharyngeal carcinoma, followed closely by SPECT/CT. SPECT/CT had poorer specificity than that of both MRI and CT, while CT had the lowest sensitivity.

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

    SciTech Connect

    Jacob, Rick E.; Lamm, W. J.; Einstein, Daniel R.; Krueger, Melissa; Glenny, Robb W.; Corley, Richard A.

    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 examining 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.

  7. Head-to-head comparison of procalcitonin and presepsin for the diagnosis of sepsis in critically ill adult patients: a protocol for a systematic review and meta-analysis

    PubMed Central

    Hayashida, Kei; Kondo, Yutaka; Hara, Yoshitaka; Aihara, Morio; Yamakawa, Kazuma

    2017-01-01

    Introduction Early diagnosis and immediate therapeutic intervention, including appropriate antibiotic therapy and goal-directed resuscitation, are necessary to reduce mortality in patients with sepsis. However, a single clinical or biological marker indicative of sepsis has not been adopted unanimously. Although procalcitonin and presepsin are promising biomarkers that can effectively differentiate between sepsis/infection and systemic inflammatory response syndrome of non-infectious origin, little is known about which marker is superior. Methods and analysis We will conduct a systematic review and meta-analysis of procalcitonin and presepsin for the diagnosis of sepsis/infection in critically ill adult patients. The primary objective is to evaluate the diagnostic accuracy of these 2 biomarkers to a reference standard of sepsis/infection and to compare the diagnostic accuracy with each other. We will search electronic bibliographic databases such as MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials for retrospective and prospective diagnostic test studies. We will assign 2 reviewers to review all collected titles and associated abstracts, review full articles, and extract study data. We will use the Quality of Diagnostic Accuracy Studies-II tool to report study characteristics and to evaluate methodological quality. If pooling is possible, we will use bivariate random effects and hierarchical summary receiver operating characteristic (ROC) models to calculate parameter estimates to output summary ROCs, pooled sensitivity and specificity data, and 95% CIs around the summary operating point. We will also assess heterogeneity via clinical and methodological subgroup and sensitivity analyses. Ethics and dissemination This systematic review will provide guidance on the triage of these tests, help to determine whether existing tests should be revised or replaced, and may also identify knowledge gaps in sepsis diagnosis that could direct further research in the field. Research ethics is not required for this review. The findings will be reported at conferences and in peer-reviewed publications. Trial registration number CRD42016035784. PMID:28264831

  8. A Head-to-Head Comparison of the Personality Inventory for DSM-5 (PID-5) With the Personality Diagnostic Questionnaire-4 (PDQ-4) in Predicting the General Level of Personality Pathology Among Community Dwelling Subjects.

    PubMed

    Fossati, Andrea; Somma, Antonella; Borroni, Serena; Maffei, Cesare; Markon, Kristian E; Krueger, Robert F

    2016-02-01

    In order to evaluate if measures of DSM-5 Alternative PD Model domains predicted interview-based scores of general personality pathology when compared to self-report measures of DSM-IV Axis II/DSM-5 Section II PD criteria, 300 Italian community adults were administered the Iowa Personality Disorder Screen (IPDS) interview, the Personality Inventory for DSM-5 (PID-5), and the Personality Diagnostic Questionnaire-4+ (PDQ-4+). Multiple regression analyses showed that the five PID-5 domain scales collectively explained an adequate rate of the variance of the IPDS interview total score. This result was slightly lower than the amount of variance in the IPDS total score explained by the 10 PDQ-4+ scales. The PID-5 traits scales performed better than the PDQ-4+, although the difference was marginal. Hierarchical regression analyses revealed that the PID-5 domain and trait scales provided a moderate, but significant increase in the prediction of the general level of personality pathology above and beyond the PDQ-4+ scales.

  9. Head-to-head comparison of 11C-PiB and 18F-FC119S for Aβ imaging in healthy subjects, mild cognitive impairment patients, and Alzheimer's disease patients.

    PubMed

    Byun, Byung Hyun; Kim, Byung Il; Park, Su Yeon; Ko, In Ok; Lee, Kyo Chul; Kim, Kyeong Min; Kim, Yu Kyeong; Lee, Jun-Young; Bu, Seon Hee; Kim, Jung Hwa; Chi, Dae Yoon; Ha, Jeong Ho; Lim, Sang Moo

    2017-03-01

    As a new beta amyloid (Aβ) positron emission tomography (PET) tracer, F-FC119S has shown higher cortical uptake in patients with Alzheimer's disease (AD) than that in healthy control subjects without adverse effects in a previous preliminary study. The aim of this study was to compare F-FC119S PET and C-PiB PET in healthy control (HC) subjects, mild cognitive impairment (MCI) patients, and AD patients.A total of 48 subjects, including 28 HC subjects, 10 MCI patients, and 10 AD patients, underwent static F-FC119S PET (30 minutes after intravenous [i.v.] injection) and C-PiB PET (40 minutes after i.v. injection) on the same day. Both PET images were visually and quantitatively assessed. Standardized uptake value ratios (SUVRs) were calculated for each brain region using the cerebellar cortex as a reference region.None (0%) of the 28 HC subjects and 4 (40%) of 10 MCI patients had positive scans on both PET images. Of the 10 AD patients, 7 (70%) had positive scans on C-PiB PET while 6 (60%) had positive scans on F-FC119S PET. Overall, 47 (98%) of 48 participants showed identical results based on visual analysis. Cortical SUVR of F-FC119S was higher in AD patients (1.38 ± 0.16), followed by that in MCI patients (1.24 ± 0.10) and in HC subjects (1.14 ± 0.05). Compared with C-PiB PET, F-FC119S PET yielded a higher effect size (d = 2.02 vs. 1.67) in AD patients and a slightly lower effect size (d = 1.26 vs. 1.38) in MCI patients. In HC subjects, the nonspecific binding of F-FC119S to white matter (with the frontal cortex-to-white matter SUV ratio of 0.76) was slightly lower than that of C-PiB (ratio of 0.73). There was a significant linear correlation (slope = 0.41, r = 0.78, P < 0.001) between C-PiB and F-FC119S cortical SUVR.We could safely obtain images similar to C-PiB PET imaging Aβ in the brain using F-FC119S PET. Therefore, F-FC119S might be suitable for imaging Aβ deposition.

  10. Head-to-head comparison of 11C-PiB and 18F-FC119S for Aβ imaging in healthy subjects, mild cognitive impairment patients, and Alzheimer's disease patients

    PubMed Central

    Byun, Byung Hyun; Kim, Byung Il; Park, Su Yeon; Ko, In Ok; Lee, Kyo Chul; Kim, Kyeong Min; Kim, Yu Kyeong; Lee, Jun-Young; Bu, Seon Hee; Kim, Jung Hwa; Chi, Dae Yoon; Ha, Jeong Ho; Lim, Sang Moo

    2017-01-01

    Abstract As a new beta amyloid (Aβ) positron emission tomography (PET) tracer, 18F-FC119S has shown higher cortical uptake in patients with Alzheimer's disease (AD) than that in healthy control subjects without adverse effects in a previous preliminary study. The aim of this study was to compare 18F-FC119S PET and 11C-PiB PET in healthy control (HC) subjects, mild cognitive impairment (MCI) patients, and AD patients. A total of 48 subjects, including 28 HC subjects, 10 MCI patients, and 10 AD patients, underwent static 18F-FC119S PET (30 minutes after intravenous [i.v.] injection) and 11C-PiB PET (40 minutes after i.v. injection) on the same day. Both PET images were visually and quantitatively assessed. Standardized uptake value ratios (SUVRs) were calculated for each brain region using the cerebellar cortex as a reference region. None (0%) of the 28 HC subjects and 4 (40%) of 10 MCI patients had positive scans on both PET images. Of the 10 AD patients, 7 (70%) had positive scans on 11C-PiB PET while 6 (60%) had positive scans on 18F-FC119S PET. Overall, 47 (98%) of 48 participants showed identical results based on visual analysis. Cortical SUVR of 18F-FC119S was higher in AD patients (1.38 ± 0.16), followed by that in MCI patients (1.24 ± 0.10) and in HC subjects (1.14 ± 0.05). Compared with 11C-PiB PET, 18F-FC119S PET yielded a higher effect size (d = 2.02 vs. 1.67) in AD patients and a slightly lower effect size (d = 1.26 vs. 1.38) in MCI patients. In HC subjects, the nonspecific binding of 18F-FC119S to white matter (with the frontal cortex-to-white matter SUV ratio of 0.76) was slightly lower than that of 11C-PiB (ratio of 0.73). There was a significant linear correlation (slope = 0.41, r = 0.78, P < 0.001) between 11C-PiB and 18F-FC119S cortical SUVR. We could safely obtain images similar to 11C-PiB PET imaging Aβ in the brain using 18F-FC119S PET. Therefore, 18F-FC119S might be suitable for imaging Aβ deposition. PMID:28328855

  11. A Head-to-Head Comparison of the Personality Inventory for DSM-5 (PID-5) With the Personality Diagnostic Questionnaire-4 (PDQ-4) in Predicting the General Level of Personality Pathology Among Community Dwelling Subjects.

    PubMed

    Fossati, Andrea; Somma, Antonella; Borroni, Serena; Maffei, Cesare; Markon, Kristian E; Krueger, Robert F

    2015-02-24

    In order to evaluate if measures of DSM-5 Alternative PD Model domains predicted interview-based scores of general personality pathology when compared to self-report measures of DSM-IV Axis II/DSM-5 Section II PD criteria, 300 Italian community adults were administered the Iowa Personality Disorder Screen (IPDS) interview, the Personality Inventory for DSM-5 (PID-5), and the Personality Diagnostic Questionnaire-4+ (PDQ-4+). Multiple regression analyses showed that the five PID-5 domain scales collectively explained an adequate rate of the variance of the IPDS interview total score. This result was slightly lower than the amount of variance in the IPDS total score explained by the 10 PDQ-4+ scales. The PID-5 traits scales performed better than the PDQ-4+, although the difference was marginal. Hierarchical regression analyses revealed that the PID-5 domain and trait scales provided a moderate, but significant increase in the prediction of the general level of personality pathology above and beyond the PDQ-4+ scales.

  12. Head-to-head comparison of intensive lifestyle intervention (U-TURN) versus conventional multifactorial care in patients with type 2 diabetes: protocol and rationale for an assessor-blinded, parallel group and randomised trial

    PubMed Central

    Ried-Larsen, Mathias; Hansen, Katrine B; Johansen, Mette Y; Pedersen, Maria; Zacho, Morten; Hansen, Louise S; Kofoed, Katja; Thomsen, Katja; Jensen, Mette S; Nielsen, Rasmus O; MacDonald, Chris; Langberg, Henning; Vaag, Allan A; Pedersen, Bente K; Karstoft, Kristian

    2015-01-01

    Introduction Current pharmacological therapies in patients with type 2 diabetes (T2D) are challenged by lack of sustainability and borderline firm evidence of real long-term health benefits. Accordingly, lifestyle intervention remains the corner stone in the management of T2D. However, there is a lack of knowledge regarding the optimal intervention programmes in T2D ensuring both compliance as well as long-term health outcomes. Our objective is to assess the effects of an intensive lifestyle intervention (the U-TURN intervention) on glycaemic control in patients with T2D. Our hypothesis is that intensive lifestyle changes are equally effective as standard diabetes care, including pharmacological treatment in maintaining glycaemic control (ie, glycated haemoglobin (HbA1c)) in patients with T2D. Furthermore, we expect that intensive lifestyle changes will decrease the need for antidiabetic medications. Methods and analysis The study is an assessor-blinded, parallel group and a 1-year randomised trial. The primary outcome is change in glycaemic control (HbA1c), with the key secondary outcome being reductions in antidiabetic medication. Participants will be patients with T2D (T2D duration <10 years) without complications who are randomised into an intensive lifestyle intervention (U-TURN) or a standard care intervention in a 2:1 fashion. Both groups will be exposed to the same standardised, blinded, target-driven pharmacological treatment and can thus maintain, increase, reduce or discontinue the pharmacological treatment. The decision is based on the standardised algorithm. The U-TURN intervention consists of increased training and basal physical activity level, and an antidiabetic diet including an intended weight loss. The standard care group as well as the U-TURN group is offered individual diabetes management counselling on top of the pharmacological treatment. Ethics and dissemination This study has been approved by the Scientific Ethical Committee at the Capital Region of Denmark (H-1–2014–114). Positive, negative or inconclusive findings will be disseminated in peer-reviewed journals, at national and international conferences. Trial registration number NCT02417012. PMID:26656025

  13. Evaluation of the ΔV 4D CT ventilation calculation method using in vivo xenon CT ventilation data and comparison to other methods.

    PubMed

    Zhang, Geoffrey G; Latifi, Kujtim; Du, Kaifang; Reinhardt, Joseph M; Christensen, Gary E; Ding, Kai; Feygelman, Vladimir; Moros, Eduardo G

    2016-03-08

    Ventilation distribution calculation using 4D CT has shown promising potential in several clinical applications. This study evaluated the direct geometric ventilation calculation method, namely the ΔV method, with xenon-enhanced CT (XeCT) ventilation data from four sheep, and compared it with two other published meth-ods, the Jacobian and the Hounsfield unit (HU) methods. Spearman correlation coefficient (SCC) and Dice similarity coefficient (DSC) were used for the evaluation and comparison. The average SCC with one standard deviation was 0.44 ± 0.13 with a range between 0.29 and 0.61 between the XeCT and ΔV ventilation distributions. The average DSC value for lower 30% ventilation volumes between the XeCT and ΔV ventilation distributions was 0.55 ± 0.07 with a range between 0.48 and 0.63. Ventilation difference introduced by deformable image registration errors improved with smoothing. In conclusion, ventilation distributions generated using ΔV-4D CT and deformable image registration are in reasonably agreement with the in vivo XeCT measured ventilation distribution.

  14. A retrospective comparison of smart prep and test bolus multi-detector CT pulmonary angiography protocols

    SciTech Connect

    Suckling, Tara; Smith, Tony; Reed, Warren

    2013-06-15

    Optimal arterial opacification is crucial in imaging the pulmonary arteries using computed tomography (CT). This poses the challenge of precisely timing data acquisition to coincide with the transit of the contrast bolus through the pulmonary vasculature. The aim of this quality assurance exercise was to investigate if a change in CT pulmonary angiography (CTPA) scanning protocol resulted in improved opacification of the pulmonary arteries. Comparison was made between the smart prep protocol (SPP) and the test bolus protocol (TBP) for opacification in the pulmonary trunk. A total of 160 CTPA examinations (80 using each protocol) performed between January 2010 and February 2011 were assessed retrospectively. CT attenuation coefficients were measured in Hounsfield Units (HU) using regions of interest at the level of the pulmonary trunk. The average pixel value, standard deviation (SD), maximum, and minimum were recorded. For each of these variables a mean value was then calculated and compared for these two CTPA protocols. Minimum opacification of 200 HU was achieved in 98% of the TBP sample but only 90% of the SPP sample. The average CT attenuation over the pulmonary trunk for the SPP was 329 (SD = ±21) HU, whereas for the TBP it was 396 (SD = ±22) HU (P = 0.0017). The TBP also recorded higher maximum (P = 0.0024) and minimum (P = 0.0039) levels of opacification. This study has found that a TBP resulted in significantly better opacification of the pulmonary trunk than the SPP.

  15. Localization of islet cell tumors by dynamic CT: comparison with plain CT, arteriography, sonography, and venous sampling

    SciTech Connect

    Krudy, A.G.; Doppman, J.L.; Jensen, R.T.; Norton, J.A.; Collen, M.J.; Shawker, T.H.; Gardner, J.D.; McArthur, K.; Gorden, P.

    1984-09-01

    Ten patients with suspected islet cell tumors (seven with possible gastrinomas, three with insulinomas) underwent diagnostic evaluation with dynamic CT scanning, routine CT scanning, angiography, and sonography. Venous sampling was also performed in selected instances. Nine sites of gastrinoma and three insulinomas were confirmed surgically in eight patients. Two patients had negative surgical explorations. Routine CT demonstrated five of the nine gastrinomas and one of two insulinomas. Angiography was positive in six of nine gastrinomas and all three insulinomas. Sonography showed only two of the nine gastrinomas and two of the three insulinomas. Dynamic CT scanning demonstrated three additional lesions (two gastrinomas, on insulinoma) not visible on routine CT scanning. Although most of these lesions were visible arteriographically, dynamic CT scans at the appropriate level localized the pathology in the transverse plane and greatly aided in surgical resection of these lesions.

  16. Comparison of volumetric breast density estimations from mammography and thorax CT.

    PubMed

    Geeraert, N; Klausz, R; Cockmartin, L; Muller, S; Bosmans, H; Bloch, I

    2014-08-07

    Breast density has become an important issue in current breast cancer screening, both as a recognized risk factor for breast cancer and by decreasing screening efficiency by the masking effect. Different qualitative and quantitative methods have been proposed to evaluate area-based breast density and volumetric breast density (VBD). We propose a validation method comparing the computation of VBD obtained from digital mammographic images (VBDMX) with the computation of VBD from thorax CT images (VBDCT). We computed VBDMX by applying a conversion function to the pixel values in the mammographic images, based on models determined from images of breast equivalent material. VBDCT is computed from the average Hounsfield Unit (HU) over the manually delineated breast volume in the CT images. This average HU is then compared to the HU of adipose and fibroglandular tissues from patient images. The VBDMX method was applied to 663 mammographic patient images taken on two Siemens Inspiration (hospL) and one GE Senographe Essential (hospJ). For the comparison study, we collected images from patients who had a thorax CT and a mammography screening exam within the same year. In total, thorax CT images corresponding to 40 breasts (hospL) and 47 breasts (hospJ) were retrieved. Averaged over the 663 mammographic images the median VBDMX was 14.7% . The density distribution and the inverse correlation between VBDMX and breast thickness were found as expected. The average difference between VBDMX and VBDCT is smaller for hospJ (4%) than for hospL (10%). This study shows the possibility to compare VBDMX with the VBD from thorax CT exams, without additional examinations. In spite of the limitations caused by poorly defined breast limits, the calibration of mammographic images to local VBD provides opportunities for further quantitative evaluations.

  17. Comparison of volumetric breast density estimations from mammography and thorax CT

    NASA Astrophysics Data System (ADS)

    Geeraert, N.; Klausz, R.; Cockmartin, L.; Muller, S.; Bosmans, H.; Bloch, I.

    2014-08-01

    Breast density has become an important issue in current breast cancer screening, both as a recognized risk factor for breast cancer and by decreasing screening efficiency by the masking effect. Different qualitative and quantitative methods have been proposed to evaluate area-based breast density and volumetric breast density (VBD). We propose a validation method comparing the computation of VBD obtained from digital mammographic images (VBDMX) with the computation of VBD from thorax CT images (VBDCT). We computed VBDMX by applying a conversion function to the pixel values in the mammographic images, based on models determined from images of breast equivalent material. VBDCT is computed from the average Hounsfield Unit (HU) over the manually delineated breast volume in the CT images. This average HU is then compared to the HU of adipose and fibroglandular tissues from patient images. The VBDMX method was applied to 663 mammographic patient images taken on two Siemens Inspiration (hospL) and one GE Senographe Essential (hospJ). For the comparison study, we collected images from patients who had a thorax CT and a mammography screening exam within the same year. In total, thorax CT images corresponding to 40 breasts (hospL) and 47 breasts (hospJ) were retrieved. Averaged over the 663 mammographic images the median VBDMX was 14.7% . The density distribution and the inverse correlation between VBDMX and breast thickness were found as expected. The average difference between VBDMX and VBDCT is smaller for hospJ (4%) than for hospL (10%). This study shows the possibility to compare VBDMX with the VBD from thorax CT exams, without additional examinations. In spite of the limitations caused by poorly defined breast limits, the calibration of mammographic images to local VBD provides opportunities for further quantitative evaluations.

  18. CT image quality over time: comparison of image quality for six different CT scanners over a six-year period.

    PubMed

    Roa, Ana Maria A; Andersen, Hilde K; Martinsen, Anne Catrine T

    2015-03-08

    UNSCEAR concluded that increased use of CT scanning caused dramatic changes in population dose. Therefore, international radiation protection authorities demand: 1) periodical quality assurance tests with respect to image quality and radiation dose, and 2) optimization of all examination protocols with respect to image quality and radiation dose. This study aimed to evaluate and analyze multiple image quality parameters and variability measured throughout time for six different CT scanners from four different vendors, in order to evaluate the current methodology for QA controls of CT systems. The results from this study indicate that there is minor drifting in the image noise and uniformity and in the spatial resolution over time for CT scanners, independent of vendors. The HU for different object densities vary between different CT scanner models from different vendors, and over time for one specific CT scanner. Future tests of interphantom and intraphantom variations, along with inclusion of more CT scanners, are necessary to establish robust baselines and recommendations of methodology for QA controls of CT systems, independent of model and vendor.

  19. Comparison of full-scan and half-scan for cone beam breast CT imaging

    NASA Astrophysics Data System (ADS)

    Chen, Lingyun; Shaw, Chris C.; Lai, Chao-jen; Altunbas, Mustafa C.; Wang, Tianpeng; Tu, Shu-ju; Liu, Xinming

    2006-03-01

    The half-scan cone beam technique, requiring a scan for 180° plus detector width only, can help achieve both shorter scan time as well as higher exposure in each individual projection image. This purpose of this paper is to investigate whether half-scan cone beam CT technique can provide acceptable images for clinical application. The half-scan cone beam reconstruction algorithm uses modified Parker's weighting function and reconstructs from slightly more than half of the projection views for full-scan, giving out promising results. A rotation phantom, stationary gantry bench top system was built to conduct experiments to evaluate half-scan cone beam breast CT technique. A post-mastectomy breast specimen, a stack of lunch meat slices embedded with various sizes of calcifications and a polycarbonate phantom inserted with glandular and adipose tissue equivalents are imaged and reconstructed for comparison study. A subset of full-scan projection images of a mastectomy specimen were extracted and used as the half-scan projection data for reconstruction. The results show half-scan reconstruction algorithm for cone beam breast CT images does not significantly degrade image quality when compared with the images of same or even half the radiation dose level. Our results are encouraging, emphasizing the potential advantages in the use of half-scan technique for cone beam breast imaging.

  20. Comparison of manual and automatic MR-CT registration for radiotherapy of prostate cancer.

    PubMed

    Korsager, Anne Sofie; Carl, Jesper; Østergaard, Lasse Riis

    2016-05-01

    In image-guided radiotherapy (IGRT) of prostate cancer, delineation of the clinical target volume (CTV) often relies on magnetic resonance (MR) because of its good soft-tissue visualization. Registration of MR and computed tomography (CT) is required in order to add this accurate delineation to the dose planning CT. An automatic approach for local MR-CT registration of the prostate has previously been developed using a voxel property-based registration as an alternative to a manual landmark-based registration. The aim of this study is to compare the two registration approaches and to investigate the clinical potential for replacing the manual registration with the automatic registration. Registrations and analysis were performed for 30 prostate cancer patients treated with IGRT using a Ni-Ti prostate stent as a fiducial marker. The comparison included computing translational and rotational differences between the approaches, visual inspection, and computing the overlap of the CTV. The computed mean translational difference was 1.65, 1.60, and 1.80 mm and the computed mean rotational difference was 1.51°, 3.93°, and 2.09° in the superior/inferior, anterior/posterior, and medial/lateral direction, respectively. The sensitivity of overlap was 87%. The results demonstrate that the automatic registration approach performs registrations comparable to the manual registration. PACS number(s): 87.57.nj, 87.61.-c, 87.57.Q-, 87.56.J.

  1. Comparison of FDG-PET/CT and CT for Delineation of Lumpectomy Cavity for Partial Breast Irradiation

    SciTech Connect

    Ford, Eric C. Lavely, William C.; Frassica, Deborah A.; Myers, Lee T.; Asrari, Fariba; Wahl, Richard L.; Zellars, Richard C.

    2008-06-01

    Purpose: The success of partial breast irradiation critically depends on proper target localization. We examined the use of fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) for improved lumpectomy cavity (LC) delineation and treatment planning. Methods and Materials: Twelve breast cancer patients underwent FDG-PET/CT on a GE Discovery scanner with a median time from surgery to PET/CT of 49 days. The LC was contoured on the CT scan by a radiation oncologist and, together with a nuclear medicine physician, on the PET/CT scan. The volumes were calculated and compared in each patient. Treatment planning target volumes (PTVs) were calculated by expanding the margin 2 cm beyond the LC, maintaining a 5-mm margin from the skin and chest wall, and the treatment plans were evaluated. In addition, a study with a patient-like phantom was conducted to evaluate the effect that the window/level settings might have on contouring. Results: The margin of the LC was well visualized on all FDG-PET images. The phantom results indicated that the difference between the known volume and the FDG-PET-delineated volume was <10%, regardless of the window/level settings. The PET/CT volumes were larger than the CT volumes in all cases (median volume ratio, 1.68; range, 1.24-2.45; p = 0.004). The PET/CT-based PTVs were also larger than the CT-based PTV (median volume ratio, 1.16; range, 1.08-1.64; p = 0.006). In 9 of 12 patients, a CT-based treatment plan did not provide adequate coverage of the PET/CT-based PTV (99% of the PTV received <95% of the prescribed dose), resulting in substantial cold spots in some plans. In these cases, treatment plans were generated which were specifically designed to cover the larger PET/CT-based PTV. Although these plans showed an increased dose to the normal tissues, the increases were modest: the non-target breast volume receiving {>=}50 Gy, lung volume receiving {>=}30 Gy, and heart volume receiving {>=}5 Gy increased by 5

  2. Imaging lobular breast carcinoma: comparison of synchrotron radiation DEI-CT technique with clinical CT, mammography and histology

    NASA Astrophysics Data System (ADS)

    Fiedler, S.; Bravin, A.; Keyriläinen, J.; Fernández, M.; Suortti, P.; Thomlinson, W.; Tenhunen, M.; Virkkunen, P.; Karjalainen-Lindsberg, M.-L.

    2004-01-01

    Different modalities for imaging cancer-bearing breast tissue samples are described and compared. The images include clinical mammograms and computed tomography (CT) images, CT images with partly coherent synchrotron radiation (SR), and CT and radiography images taken with SR using the diffraction enhanced imaging (DEI) method. The images are evaluated by a radiologist and compared with histopathological examination of the samples. Two cases of lobular carcinoma are studied in detail. The indications of cancer are very weak or invisible in the conventional images, but the morphological changes due to invasion of cancer become pronounced in the images taken by the DEI method. The strands penetrating adipose tissue are seen clearly in the DEI-CT images, and the histopathology confirms that some strands contain the so-called 'Indian file' formations of cancer cells. The radiation dose is carefully measured for each of the imaging modalities. The mean glandular dose (MGD) for 50% glandular breast tissue is about 1 mGy in conventional mammography and less than 0.25 mGy in projection DEI, while in the clinical CT imaging the MGD is very high, about 45 mGy. The entrance dose of 95 mGy in DEI-CT imaging gives rise to an MGD of 40 mGy, but the dose may be reduced by an order of magnitude, because the contrast is very large in most images.

  3. Imaging of Orthotopic Glioblastoma Xenografts in Mice Using a Clinical CT Scanner: Comparison with Micro-CT and Histology

    PubMed Central

    Kirschner, Stefanie; Mürle, Bettina; Felix, Manuela; Arns, Anna; Groden, Christoph; Wenz, Frederik; Hug, Andreas; Glatting, Gerhard; Kramer, Martin

    2016-01-01

    Purpose There is an increasing need for small animal in vivo imaging in murine orthotopic glioma models. Because dedicated small animal scanners are not available ubiquitously, the applicability of a clinical CT scanner for visualization and measurement of intracerebrally growing glioma xenografts in living mice was validated. Materials and Methods 2.5x106 U87MG cells were orthotopically implanted in NOD/SCID/ᵞc-/- mice (n = 9). Mice underwent contrast-enhanced (300 μl Iomeprol i.v.) imaging using a micro-CT (80 kV, 75 μAs, 360° rotation, 1,000 projections, scan time 33 s, resolution 40 x 40 x 53 μm) and a clinical CT scanner (4-row multislice detector; 120 kV, 150 mAs, slice thickness 0.5 mm, feed rotation 0.5 mm, resolution 98 x 98 x 500 μm). Mice were sacrificed and the brain was worked up histologically. In all modalities tumor volume was measured by two independent readers. Contrast-to-noise ratio (CNR) and Signal-to-noise ratio (SNR) were measured from reconstructed CT-scans (0.5 mm slice thickness; n = 18). Results Tumor volumes (mean±SD mm3) were similar between both CT-modalities (micro-CT: 19.8±19.0, clinical CT: 19.8±18.8; Wilcoxon signed-rank test p = 0.813). Moreover, between reader analyses for each modality showed excellent agreement as demonstrated by correlation analysis (Spearman-Rho >0.9; p<0.01 for all correlations). Histologically measured tumor volumes (11.0±11.2) were significantly smaller due to shrinkage artifacts (p<0.05). CNR and SNR were 2.1±1.0 and 1.1±0.04 for micro-CT and 23.1±24.0 and 1.9±0.7 for the clinical CTscanner, respectively. Conclusion Clinical CT scanners may reliably be used for in vivo imaging and volumetric analysis of brain tumor growth in mice. PMID:27829015

  4. CT imaging of bone and bone marrow infiltration in malignant melanoma--Challenges and limitations for clinical staging in comparison to 18FDG-PET/CT.

    PubMed

    Bier, Georg; Hoffmann, Vera; Kloth, Christopher; Othman, Ahmed E; Eigentler, Thomas; Garbe, Claus; La Fougère, Christian; Pfannenberg, Christina; Nikolaou, Konstantin; Klumpp, Bernhard

    2016-04-01

    Rationale of this study was the evaluation of the diagnostic value of computed tomography (CT) in the detection of bone marrow infiltration in comparison to PET/CT. Fifty patients (age 61 ± 15.12 years) with metastatic malignant melanoma underwent 18F-FDG-PET/CT, including contrast-enhanced CT. 2 readers evaluated the CT images in consensus for bone and bone marrow lesions focusing on lesion location, type and size. PET/CT was used as reference standard to estimate sensitivity, specificity, negative and positive predictive value. Moreover, the bone marrow density was estimated in the long bones and the sacral bone. Serum hamoglobin, thrombocyte level and S100 protein were correlated with the presence or absence of bone and bone marrow lesions. According to PET/CT as standard of reference, of 594 bone and medullary lesions 495 were considered malignant. Of these 77.8% were medullary, 20.4% lytic, 1% sclerotic and 0.8% mixed lytic/sclerotic. Contrast-enhanced CT yielded a lesion-based sensitivity of 36.8% and a specificity of 87.9% (PPV 93.8%; NPV 21.8%). Patient-based sensitivity and specificity were 78.8% and 82.4%, respectively. Of the missed lesions, most were medullary (95.8%). A disseminated bone marrow involvement (defined as >10 bone marrow lesions or diffuse infiltration of a whole body segment) was described in 11 cases, in 6 cases the disseminated involvement was underestimated or missed on CT. In cases with disseminated bone marrow involvement the bone marrow density was significantly higher in the humerus (p=0.04), but not in the femur or sacral bone (p=0.06). Multivariate analysis revealed no isolated effect of bone metastases on S100 serum and hemoglobin level, but both were significantly altered in patients with disseminated bone marrow involvement (p<0.05). In conclusion, the diagnostic value of computed tomography for the detection of bone marrow metastases in patients with melanoma, is limited. Especially in cases with disseminated bone marrow

  5. Dual energy with dual source CT and kVp switching with single source CT: a comparison of dual energy performance

    NASA Astrophysics Data System (ADS)

    Grasruck, M.; Kappler, S.; Reinwand, M.; Stierstorfer, K.

    2009-02-01

    Stimulated by the introduction of clinical dual source CT, the interest in dual energy methods has been increasing in the past years. Whereas the potential of material decomposition by dual energy methods is known since the early 1980ies, the realization of dual energy methods is a wide field of today's research. Energy separation can be achieved with energy selective detectors or by varying X-ray source spectra. This paper focuses on dual energy techniques with varying X-ray spectra. These can be provided by dual source CT devices, operated with different kVp settings on each tube. Excellent spectral separation is the key property for use in clinical routine. The drawback of higher cost for two tubes and two detectors leads to an alternative realization, where a single source CT yields different spectra by fast kVp switching from reading to reading. This provides access to dual-energy methods in single source CT. However, this technique comes with some intrinsic limitations. The maximum X-ray flux is reduced in comparison to the dual source system. The kVp rise and fall time between each reading reduces the spectral separation. In comparison to dual source CT, for a constant number of projections per energy spectrum the temporal resolution is reduced; a reasonable trade of between reduced numbers of projection and limited temporal resolution has to be found. The overall dual energy performance is the guiding line for our investigations. We present simulations and measurements which benchmark both solutions in terms of spectral behavior, especially of spectral separation.

  6. Percutaneous Bone Biopsies: Comparison between Flat-Panel Cone-Beam CT and CT-Scan Guidance

    SciTech Connect

    Tselikas, Lambros Joskin, Julien; Roquet, Florian; Farouil, Geoffroy; Dreuil, Serge; Hakimé, Antoine Teriitehau, Christophe; Auperin, Anne; Baere, Thierry de Deschamps, Frederic

    2015-02-15

    PurposeThis study was designed to compare the accuracy of targeting and the radiation dose of bone biopsies performed either under fluoroscopic guidance using a cone-beam CT with real-time 3D image fusion software (FP-CBCT-guidance) or under conventional computed tomography guidance (CT-guidance).MethodsSixty-eight consecutive patients with a bone lesion were prospectively included. The bone biopsies were scheduled under FP-CBCT-guidance or under CT-guidance according to operating room availability. Thirty-four patients underwent a bone biopsy under FP-CBCT and 34 under CT-guidance. We prospectively compared the two guidance modalities for their technical success, accuracy, puncture time, and pathological success rate. Patient and physician radiation doses also were compared.ResultsAll biopsies were technically successful, with both guidance modalities. Accuracy was significantly better using FP-CBCT-guidance (3 and 5 mm respectively: p = 0.003). There was no significant difference in puncture time (32 and 31 min respectively, p = 0.51) nor in pathological results (88 and 88 % of pathological success respectively, p = 1). Patient radiation doses were significantly lower with FP-CBCT (45 vs. 136 mSv, p < 0.0001). The percentage of operators who received a dose higher than 0.001 mSv (dosimeter detection dose threshold) was lower with FP-CBCT than CT-guidance (27 vs. 59 %, p = 0.01).ConclusionsFP-CBCT-guidance for bone biopsy is accurate and reduces patient and operator radiation doses compared with CT-guidance.

  7. Local variations in bone mineral density: a comparison of OCT versus x-ray micro-CT

    NASA Astrophysics Data System (ADS)

    Ugryumova, Nadya; Stevens-Smith, Jenna; Scutt, Andrew; Matcher, Stephen J.

    2008-02-01

    We describe variations in the degree of mineralisation within the subchondral bone plate of the equine metacarpophalangeal joint. A comparison of Optical Coherence Tomography, Micro CT, and SEM techniques was performed. These data are compared between sites on a healthy sample and at points on an osteoarthritically degenerated sample. No significant correlation was found between the optical scattering coefficient and the micro-CT derived BMD for comparisons between different sites on the bone surface. Also OCT demonstrated a larger regional variation in scattering coefficient than did micro CT for bone mineral density. This suggests that the optical scattering coefficient of bone is not related solely to the volume-density of calcium-phosphate. Patches of lower optical scattering coefficient were found in the bone structure that was related to the osteoarthritic lesion area on the overlying cartilage. Areas of microcracking, as revealed by both SEM and micro CT produced distinctive granularity in the OCT images. In further experiments, OCT was compared with micro CT and mechanical strength testing (3-point bending) in a small animal model of cardiovascular disease (cholesterol overload in mice). In the cardiovascular diseased mice, micro-CT of the trabecular bone did not demonstrate a significant change in trabecular bone mineral density before and after administration of the high cholesterol diet. However mechanical testing demonstrated a decrease in mechanical strength and OCT demonstrated a corresponding statistically significant decrease in optical scattering of the bone.

  8. Comparison of CT-Number and Gray Scale Value of Different Dental Materials and Hard Tissues in CT and CBCT

    PubMed Central

    Emadi, Naghmeh; Safi, Yaser; Akbarzadeh Bagheban, Alireza; Asgary, Saeed

    2014-01-01

    Introduction: Computed tomography (CT) and cone-beam CT (CBCT) are valuable diagnostic aids for many clinical applications. This study was designed to compare the gray scale value (GSV) and Hounsfield unit (HU) of selected dental materials and various hard tissues using CT or CBCT. Methods and Materials: Three samples of all test materials including amalgam (AM), composite resin (CR), glass ionomer (GI), zinc-oxide eugenol (ZOE), calcium-enriched mixture (CEM) cement, AH-26 root canal sealer (AH-26), gutta-percha (GP), Coltosol (Col), Dycal (DL), mineral trioxide aggregate (MTA), zinc phosphate (ZP), and polycarbonate cement (PC) were prepared and scanned together with samples of bone, dentin and enamel using two CBCT devices, Scanora 3D (S3D) and NewTom VGi (NTV) and a spiral CT (SCT) scanner (Somatom Emotion 16 multislice spiral CT);. Subsequently, the HU and GSV values were determined and evaluated. The data were analyzed by the Kruskal-Wallis and Mann-Whitney U tests. The level of significance was determined at 0.05. Results: There were significant differences among the three different scanners (P<0.05). The differences between HU/GSV values of 12 selected dental materials using NTV was significant (P<0.05) and for S3D and SCT was insignificant (P>0.05). All tested materials showed maximum values in S3D and SCT (3094 and 3071, respectively); however, bone and dentin showed low/medium values (P<0.05). In contrast, the tested materials and tissues showed a range of values in NTV (366 to15383; P<0.05). Conclusion: Scanner system can influence the obtained HU/GSV of dental materials. NTV can discriminate various dental materials, in contrast to S3D/SCT scanners. NTV may be a more useful diagnostic aid for clinical practice. PMID:25386210

  9. Comparison of near-infrared spectroscopy with CT cerebral blood flow measurements in newborn piglets

    NASA Astrophysics Data System (ADS)

    Brown, Derek W.; Picot, Paul A.; Springett, Roger; Delpy, David T.; Lee, Ting-Yim

    2001-05-01

    Severely premature infants are often at high risk of cerebral hemorrhage or ischemic injury due to their inability to properly regulate blood flow to the brain. If blood flow is too high, the infant is at risk of cerebral hemorrhage, while too little blood flow can result in ischemic injury. The purpose of this research is to design and develop a means of non-invasively measuring cerebral blood flow (CBF) with near infrared spectroscopy (NIRS). Such a device would greatly aid the diagnosis and monitoring of afflicted infants. Previous attempts to measure CBF with NIRS have achieved limited success. In this study we acquired high signal-to-noise NIR spectrum from 600 to 980 nm with a cooled CCD spectrometer. This spectrometer enables the differential path length factor (DPF) to be estimated with accuracy using a second derivative technique described by Matcher et al. The validity of our new approach is determined via direct comparison with a previously validated computed tomography (CT) method. Three newborn piglets were studied. CBF measurements were performed at various partial arterial CO2 tensions (PaCO2) using both the NIRS and CT methods. The results of the two methods correlate well with a relationship of CBFCT equals -4.30 + 1.05 CBFNIRS (r2 equals 0.96).

  10. Quantitative comparison of noise texture across CT scanners from different manufacturers

    SciTech Connect

    Solomon, Justin B.; Christianson, Olav; Samei, Ehsan

    2012-10-15

    Purpose: To quantitatively compare noise texture across computed tomography (CT) scanners from different manufacturers using the noise power spectrum (NPS). Methods: The American College of Radiology CT accreditation phantom (Gammex 464, Gammex, Inc., Middleton, WI) was imaged on two scanners: Discovery CT 750HD (GE Healthcare, Waukesha, WI), and SOMATOM Definition Flash (Siemens Healthcare, Germany), using a consistent acquisition protocol (120 kVp, 0.625/0.6 mm slice thickness, 250 mAs, and 22 cm field of view). Images were reconstructed using filtered backprojection and a wide selection of reconstruction kernels. For each image set, the 2D NPS were estimated from the uniform section of the phantom. The 2D spectra were normalized by their integral value, radially averaged, and filtered by the human visual response function. A systematic kernel-by-kernel comparison across manufacturers was performed by computing the root mean square difference (RMSD) and the peak frequency difference (PFD) between the NPS from different kernels. GE and Siemens kernels were compared and kernel pairs that minimized the RMSD and |PFD| were identified. Results: The RMSD (|PFD|) values between the NPS of GE and Siemens kernels varied from 0.01 mm{sup 2} (0.002 mm{sup -1}) to 0.29 mm{sup 2} (0.74 mm{sup -1}). The GE kernels 'Soft,''Standard,''Chest,' and 'Lung' closely matched the Siemens kernels 'B35f,''B43f,''B41f,' and 'B80f' (RMSD < 0.05 mm{sup 2}, |PFD| < 0.02 mm{sup -1}, respectively). The GE 'Bone,''Bone+,' and 'Edge' kernels all matched most closely with Siemens 'B75f' kernel but with sizeable RMSD and |PFD| values up to 0.18 mm{sup 2} and 0.41 mm{sup -1}, respectively. These sizeable RMSD and |PFD| values corresponded to visually perceivable differences in the noise texture of the images. Conclusions: It is possible to use the NPS to quantitatively compare noise texture across CT systems. The degree to which similar texture across scanners could be achieved varies and is

  11. Unusual Presentation of Bladder Paraganglioma: Comparison of (131)I MIBG SPECT/CT and (68)Ga DOTANOC PET/CT.

    PubMed

    Jain, Tarun Kumar; Basher, Rajender Kumar; Gupta, Nitin; Shukla, Jaya; Singh, Shrawan Kumar; Mittal, Bhagwant Rai

    2016-01-01

    Extraadrenal chromaffin cell-related tumors or paragangliomas are rare, especially in the bladder, accounting for less than 1% of cases. We report a 16-year-old boy who presented with hematuria and paroxysmal headache and was found to have a prostatic growth infiltrating the urinary bladder on anatomical imaging. Iodine-131 ((131)I) metaiodobenzylguanidine (MIBG) whole-body scanning and subsequently gallium-68 ((68)Ga) DOTANOC positron emission tomography/computed tomography (PET/CT) were performed. The MIBG scan revealed a non-tracer-avid soft-tissue mass, while DOTANOC PET/CT revealed a tracer-avid primary soft-tissue mass involving the urinary bladder and prostate with metastasis to the iliac lymph nodes. He underwent surgical management; histopathology of the surgical specimen revealed a bladder paraganglioma, whereas the prostate was found to be free of tumor.

  12. Unusual Presentation of Bladder Paraganglioma: Comparison of 131I MIBG SPECT/CT and 68Ga DOTANOC PET/CT

    PubMed Central

    Jain, Tarun Kumar; Basher, Rajender Kumar; Gupta, Nitin; Shukla, Jaya; Singh, Shrawan Kumar; Mittal, Bhagwant Rai

    2016-01-01

    Extraadrenal chromaffin cell-related tumors or paragangliomas are rare, especially in the bladder, accounting for less than 1% of cases. We report a 16-year-old boy who presented with hematuria and paroxysmal headache and was found to have a prostatic growth infiltrating the urinary bladder on anatomical imaging. Iodine-131 (131I) metaiodobenzylguanidine (MIBG) whole-body scanning and subsequently gallium-68 (68Ga) DOTANOC positron emission tomography/computed tomography (PET/CT) were performed. The MIBG scan revealed a non-tracer-avid soft-tissue mass, while DOTANOC PET/CT revealed a tracer-avid primary soft-tissue mass involving the urinary bladder and prostate with metastasis to the iliac lymph nodes. He underwent surgical management; histopathology of the surgical specimen revealed a bladder paraganglioma, whereas the prostate was found to be free of tumor. PMID:26912984

  13. Comparison of ring artifact removal methods using flat panel detector based CT images

    PubMed Central

    2011-01-01

    Background Ring artifacts are the concentric rings superimposed on the tomographic images often caused by the defective and insufficient calibrated detector elements as well as by the damaged scintillator crystals of the flat panel detector. It may be also generated by objects attenuating X-rays very differently in different projection direction. Ring artifact reduction techniques so far reported in the literature can be broadly classified into two groups. One category of the approaches is based on the sinogram processing also known as the pre-processing techniques and the other category of techniques perform processing on the 2-D reconstructed images, recognized as the post-processing techniques in the literature. The strength and weakness of these categories of approaches are yet to be explored from a common platform. Method In this paper, a comparative study of the two categories of ring artifact reduction techniques basically designed for the multi-slice CT instruments is presented from a common platform. For comparison, two representative algorithms from each of the two categories are selected from the published literature. A very recently reported state-of-the-art sinogram domain ring artifact correction method that classifies the ring artifacts according to their strength and then corrects the artifacts using class adaptive correction schemes is also included in this comparative study. The first sinogram domain correction method uses a wavelet based technique to detect the corrupted pixels and then using a simple linear interpolation technique estimates the responses of the bad pixels. The second sinogram based correction method performs all the filtering operations in the transform domain, i.e., in the wavelet and Fourier domain. On the other hand, the two post-processing based correction techniques actually operate on the polar transform domain of the reconstructed CT images. The first method extracts the ring artifact template vector using a homogeneity

  14. Comparison of Intraoperative Portable CT Scanners in Skull Base and Endoscopic Sinus Surgery: Single Center Case Series

    PubMed Central

    Conley, David B.; Tan, Bruce; Bendok, Bernard R.; Batjer, H. Hunt; Chandra, Rakesh; Sidle, Douglas; Rahme, Rudy J.; Adel, Joseph G.; Fishman, Andrew J.

    2011-01-01

    Precise and safe management of complex skull base lesions can be enhanced by intraoperative computed tomography (CT) scanning. Surgery in these areas requires real-time feedback of anatomic landmarks. Several portable CT scanners are currently available. We present a comparison of our clinical experience with three portable scanners in skull base and craniofacial surgery. We present clinical case series and the participants were from the Northwestern Memorial Hospital. Three scanners are studied: one conventional multidetector CT (MDCT), two digital flat panel cone-beam CT (CBCT) devices. Technical considerations, ease of use, image characteristics, and integration with image guidance are presented for each device. All three scanners provide good quality images. Intraoperative scanning can be used to update the image guidance system in real time. The conventional MDCT is unique in its ability to resolve soft tissue. The flat panel CBCT scanners generally emit lower levels of radiation and have less metal artifact effect. In this series, intraoperative CT scanning was technically feasible and deemed useful in surgical decision-making in 75% of patients. Intraoperative portable CT scanning has significant utility in complex skull base surgery. This technology informs the surgeon of the precise extent of dissection and updates intraoperative stereotactic navigation. PMID:22470270

  15. Personalized estimates of radiation dose from dedicated breast CT in a diagnostic population and comparison with diagnostic mammography

    NASA Astrophysics Data System (ADS)

    Vedantham, Srinivasan; Shi, Linxi; Karellas, Andrew; O'Connell, Avice M.; Conover, David L.

    2013-11-01

    This study retrospectively analyzed the mean glandular dose (MGD) to 133 breasts from 132 subjects, all women, who participated in a clinical trial evaluating dedicated breast CT in a diagnostic population. The clinical trial was conducted in adherence to a protocol approved by institutional review boards and the study participants provided written informed consent. Individual estimates of MGD to each breast from dedicated breast CT was obtained by combining x-ray beam characteristics with estimates of breast dimensions and fibroglandular fraction from volumetric breast CT images, and using normalized glandular dose coefficients. For each study participant and for the breast corresponding to that imaged with breast CT, an estimate of the MGD from diagnostic mammography (including supplemental views) was obtained from the DICOM image headers for comparison. This estimate uses normalized glandular dose coefficients corresponding to a breast with 50% fibroglandular weight fraction. The median fibroglandular weight fraction for the study cohort determined from volumetric breast CT images was 15%. Hence, the MGD from diagnostic mammography was corrected to be representative of the study cohort. Individualized estimates of MGD from breast CT ranged from 5.7 to 27.8 mGy. Corresponding to the breasts imaged with breast CT, the MGD from diagnostic mammography ranged from 2.6 to 31.6 mGy. The mean (± inter-breast SD) and the median MGD (mGy) from dedicated breast CT exam were 13.9 ± 4.6 and 12.6, respectively. For the corresponding breasts, the mean (± inter-breast SD) and the median MGD (mGy) from diagnostic mammography were 12.4 ± 6.3 and 11.1, respectively. Statistical analysis indicated that at the 0.05 level, the distributions of MGD from dedicated breast CT and diagnostic mammography were significantly different (Wilcoxon signed ranks test, p = 0.007). While the interquartile range and the range (maximum-minimum) of MGD from dedicated breast CT was lower than

  16. Comparison of dosimetry between PET/CT and PET alone using (11)C-ITMM.

    PubMed

    Ito, Kimiteru; Sakata, Muneyuki; Oda, Keiichi; Wagatsuma, Kei; Toyohara, Jun; Ishibashi, Kenji; Ishii, Kenji; Ishiwata, Kiichi

    2016-03-01

    We used a new tracer, N-[4-[6-(isopropylamino) pyrimidin-4-yl]-1,3-thiazol-2-yl]-4-(11)C-methoxy-N-methylbenzamide ((11)C-ITMM), to compare radiation doses from positron emission tomography (PET)/computed tomography (CT) with previously published doses from PET alone. Twelve healthy volunteers [six males (mean age ± SD, 27.7 ± 6.7 years) and six females (31.8 ± 14.5 years)] in 12 examinations were recruited. Dose estimations from PET/CT were compared with those from PET alone. Regions of interest (ROIs) in PET/CT were delineated on the basis of low-dose CT (LD-CT) images acquired during PET/CT. Internal and external radiation doses were estimated using OLINDA/EXM 1.0 and CT-Expo software. The effective dose (ED) for (11)C-ITMM calculated from PET/CT was estimated to be 4.7 ± 0.5 μSv/MBq for the male subjects and 4.1 ± 0.7 μSv/MBq for the female subjects. The mean ED for (11)C-ITMM calculated from PET alone in a previous report was estimated to be 4.6 ± 0.3 μSv/MBq (males, n = 3). The ED values for (11)C-ITMM calculated from PET/CT in the male subjects were almost identical to those from PET alone. The absorbed doses (ADs) of the gallbladder, stomach, red bone marrow, and spleen calculated from PET/CT were significantly different from those calculated from PET alone. The EDs of (11)C-ITMM calculated from PET/CT were almost identical to those calculated from PET alone. The ADs in several organs calculated from PET/CT differed from those from PET alone. LD-CT images acquired during PET/CT may facilitate organ identification.

  17. Somatostatin receptor based PET/CT in patients with the suspicion of cardiac sarcoidosis: an initial comparison to cardiac MRI.

    PubMed

    Lapa, Constantin; Reiter, Theresa; Kircher, Malte; Schirbel, Andreas; Werner, Rudolf A; Pelzer, Theo; Pizarro, Carmen; Skowasch, Dirk; Thomas, Lena; Schlesinger-Irsch, Ulrike; Thomas, Daniel; Bundschuh, Ralph A; Bauer, Wolfgang R; Gärtner, Florian C

    2016-11-22

    Diagnosis of cardiac sarcoidosis is often challenging. Whereas cardiac magnetic resonance imaging (CMR) and positron emission tomography/computed tomography (PET/CT) with 18F-fluorodeoxyglucose (FDG) are most commonly used to evaluate patients, PET/CT using radiolabeled somatostatin receptor (SSTR) ligands for visualization of inflammation might represent a more specific alternative. This study aimed to investigate the feasibility of SSTR-PET/CT for detecting cardiac sarcoidosis in comparison to CMR.15 patients (6 males, 9 females) with sarcoidosis and suspicion on cardiac involvement underwent SSTR-PET/CT imaging and CMR. Images were visually scored. The AHA 17-segment model of the left myocardium was used for localization and comparison of inflamed myocardium for both imaging modalities. In semi-quantitative analysis, mean (SUVmean) and maximum standardized uptake values (SUVmax) of affected myocardium were calculated and compared with both remote myocardium and left ventricular (LV) cavity.SSTR-PET was positive in 7/15, CMR in 10/15 patients. Of the 3 CMR+/PET- subjects, one patient with minor involvement (<25% of wall thickness in CMR) was missed by PET. The remaining two CMR+/PET- patients displayed no adverse cardiac events during follow-up.In the 17-segment model, PET/CT yielded 27 and CMR 29 positive segments. Overall concordance of the 2 modalities was 96.1% (245/255 segments analyzed). SUVmean and SUVmax in inflamed areas were 2.0±1.2 and 2.6±1.2, respectively. The lesion-to-remote myocardium and lesion-to-LV cavity ratios were 1.8±0.2 and 1.9±0.2 for SUVmean and 2.0±0.3 and 1.7±0.3 for SUVmax, respectively.Detection of cardiac sarcoidosis by SSTR-PET/CT is feasible. Our data warrant further analysis in larger prospective series.

  18. Somatostatin receptor based PET/CT in patients with the suspicion of cardiac sarcoidosis: an initial comparison to cardiac MRI

    PubMed Central

    Kircher, Malte; Schirbel, Andreas; Werner, Rudolf A.; Pelzer, Theo; Pizarro, Carmen; Skowasch, Dirk; Thomas, Lena; Schlesinger-Irsch, Ulrike; Thomas, Daniel; Bundschuh, Ralph A.

    2016-01-01

    Diagnosis of cardiac sarcoidosis is often challenging. Whereas cardiac magnetic resonance imaging (CMR) and positron emission tomography/computed tomography (PET/CT) with 18F-fluorodeoxyglucose (FDG) are most commonly used to evaluate patients, PET/CT using radiolabeled somatostatin receptor (SSTR) ligands for visualization of inflammation might represent a more specific alternative. This study aimed to investigate the feasibility of SSTR–PET/CT for detecting cardiac sarcoidosis in comparison to CMR. 15 patients (6 males, 9 females) with sarcoidosis and suspicion on cardiac involvement underwent SSTR-PET/CT imaging and CMR. Images were visually scored. The AHA 17-segment model of the left myocardium was used for localization and comparison of inflamed myocardium for both imaging modalities. In semi-quantitative analysis, mean (SUVmean) and maximum standardized uptake values (SUVmax) of affected myocardium were calculated and compared with both remote myocardium and left ventricular (LV) cavity. SSTR-PET was positive in 7/15, CMR in 10/15 patients. Of the 3 CMR+/PET− subjects, one patient with minor involvement (<25% of wall thickness in CMR) was missed by PET. The remaining two CMR+/PET− patients displayed no adverse cardiac events during follow-up. In the 17-segment model, PET/CT yielded 27 and CMR 29 positive segments. Overall concordance of the 2 modalities was 96.1% (245/255 segments analyzed). SUVmean and SUVmax in inflamed areas were 2.0±1.2 and 2.6±1.2, respectively. The lesion-to-remote myocardium and lesion-to-LV cavity ratios were 1.8±0.2 and 1.9±0.2 for SUVmean and 2.0±0.3 and 1.7±0.3 for SUVmax, respectively. Detection of cardiac sarcoidosis by SSTR-PET/CT is feasible. Our data warrant further analysis in larger prospective series. PMID:27780922

  19. Comparison of bone histomorphometry and μCT for evaluating bone quality in tail-suspended rats

    NASA Astrophysics Data System (ADS)

    Sun, Lian-Wen; Huang, Yun-Fei; Wang, Ying; Luan, Hui-Qin; Fan, Yu-Bo

    2014-10-01

    Astronauts often suffer from microgravity-induced osteoporosis due to their time in space. Bone histomorphometry, the 'gold standard' technique for detecting bone quality, is widely used in the evaluation of osteoporosis. This study investigates whether μCT has the same application value as histomorphometry in the evaluation of weightlessness-induced bone loss. A total of 24 SD rats were distributed into three groups (n = 8, each): tail-suspension (TS), TS plus active exercise (TSA), and control (CON). After 21 days, bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) and μCT, and microstructure was measured by μCT and histomorphometry. BMD was found to have decreased significantly in TS and TSA compared with the CON group. The results of the μCT measurements showed that a change in BMD mainly occurred in the trabecular bone, and the trabecular BMD increased significantly in the TSA compared with the TS group. The comparison of μCT and histomorphometry showed that TS led to a significant decrease in bone volume (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N), and it led to an increase in trabecular separation (Tb.Sp). However, active exercise can prevent these changes. Significant differences in most parameters between TSA and CON were found by μCT but not by histomorphometry. Additionally, the parameters of these two methods are highly correlated. Therefore, the application value of μCT is as good as histomorphometry and DXA in the diagnosis of weightlessness-induced osteoporosis and is even better in evaluating the efficacy of exercise.

  20. Comparison of computational to human observer detection for evaluation of CT low dose iterative reconstruction

    NASA Astrophysics Data System (ADS)

    Eck, Brendan; Fahmi, Rachid; Brown, Kevin M.; Raihani, Nilgoun; Wilson, David L.

    2014-03-01

    Model observers were created and compared to human observers for the detection of low contrast targets in computed tomography (CT) images reconstructed with an advanced, knowledge-based, iterative image reconstruction method for low x-ray dose imaging. A 5-channel Laguerre-Gauss Hotelling Observer (CHO) was used with internal noise added to the decision variable (DV) and/or channel outputs (CO). Models were defined by parameters: (k1) DV-noise with standard deviation (std) proportional to DV std; (k2) DV-noise with constant std; (k3) CO-noise with constant std across channels; and (k4) CO-noise in each channel with std proportional to CO variance. Four-alternative forced choice (4AFC) human observer studies were performed on sub-images extracted from phantom images with and without a "pin" target. Model parameters were estimated using maximum likelihood comparison to human probability correct (PC) data. PC in human and all model observers increased with dose, contrast, and size, and was much higher for advanced iterative reconstruction (IMR) as compared to filtered back projection (FBP). Detection in IMR was better than FPB at 1/3 dose, suggesting significant dose savings. Model(k1,k2,k3,k4) gave the best overall fit to humans across independent variables (dose, size, contrast, and reconstruction) at fixed display window. However Model(k1) performed better when considering model complexity using the Akaike information criterion. Model(k1) fit the extraordinary detectability difference between IMR and FBP, despite the different noise quality. It is anticipated that the model observer will predict results from iterative reconstruction methods having similar noise characteristics, enabling rapid comparison of methods.

  1. The accuracy of solid model and rapid prototype of prostheses in comparison to the digital CT image data

    NASA Astrophysics Data System (ADS)

    Suwandi, Agri; Kiswanto, Gandjar; Kusumaningsih, Widjajalaksmi; Soemardi, Tresna P.

    2017-02-01

    Prostheses are a derivative of biomedical products that have important things, which are: a design, size and bio compatible material. To produce optimum prostheses, safe and comfortable use, it would require design a model that fits the size of the patient's anatomy. In this paper describes the accuracy of solid model and rapid prototype of prostheses in comparison to the digital CT image data. Where the main parameters used as the reference measurement is digital CT image data. The data were analyzed using a statistical method to get the standard deviation of the comparison parameters of the data obtained, so that it can be known how the accuracy of the measurement results of each data.

  2. Evaluation of bone substitute materials: comparison of flat-panel based volume CT to conventional multidetector CT.

    PubMed

    Sauerbier, Sebastian; Duttenhoefer, Fabian; Sachlos, Elefterios; Haberstroh, Jörg; Scheifele, Christian; Wrbas, Karl-Thomas; Voss, Pit Jacob; Veigel, Egle; Smedek, Jörg; Ganter, Philip; Tuna, Taskin; Gutwald, Ralf; Palmowski, Moritz

    2013-10-01

    Over the last decade tissue engineering has emerged as a key factor in bone regeneration within the field of cranio-maxillofacial surgery. Despite this in vivo analysis of tissue-engineered-constructs to monitor bone rehabilitation are difficult to conduct. Novel high-resolving flat-panel based volume CTs (fp-VCT) are increasingly used for imaging bone structures. This study compares the potential value of novel fp-VCT with conventional multidetector CT (MDCT) based on a sheep sinus floor elevation model. Calcium-hydroxyapatite reinforced collagen scaffolds were populated with autologous osteoblasts and implanted into sheep maxillary sinus. After 8, 16 and 24 weeks MDCT and fp-VCT scans were performed to investigate the volume of the augmented area; densities of cancellous and compact bone were assessed as comparative values. fp-VCT imaging resulted in higher spatial resolution, which was advantageous when separating closely related anatomical structures (i.e. trabecular and compact bone, biomaterials). Fp-VCT facilitated imaging of alterations occurring in test specimens over time. fp-VCTs therefore displayed high volume coverage, dynamic imaging potential and superior performance when investigating superfine bone structures and bone remodelling of biomaterials. Thus, fp-VCTs may be a suitable instrument for intraoperative imaging and future in vivo tissue-engineering studies.

  3. Comparison of CT Fluoroscopy-Guided Manual and CT-Guided Robotic Positioning System for In Vivo Needle Placements in Swine Liver

    SciTech Connect

    Cornelis, F.; Takaki, H.; Laskhmanan, M.; Durack, J. C.; Erinjeri, J. P.; Getrajdman, G. I.; Maybody, M.; Sofocleous, C. T.; Solomon, S. B.; Srimathveeravalli, G.

    2015-10-15

    PurposeTo compare CT fluoroscopy-guided manual and CT-guided robotic positioning system (RPS)-assisted needle placement by experienced IR physicians to targets in swine liver.Materials and MethodsManual and RPS-assisted needle placement was performed by six experienced IR physicians to four 5 mm fiducial seeds placed in swine liver (n = 6). Placement performance was assessed for placement accuracy, procedure time, number of confirmatory scans, needle manipulations, and procedure radiation dose. Intra-modality difference in performance for each physician was assessed using paired t test. Inter-physician performance variation for each modality was analyzed using Kruskal–Wallis test.ResultsPaired comparison of manual and RPS-assisted placements to a target by the same physician indicated accuracy outcomes was not statistically different (manual: 4.53 mm; RPS: 4.66 mm; p = 0.41), but manual placement resulted in higher total radiation dose (manual: 1075.77 mGy/cm; RPS: 636.4 mGy/cm; p = 0.03), required more confirmation scans (manual: 6.6; RPS: 1.6; p < 0.0001) and needle manipulations (manual: 4.6; RPS: 0.4; p < 0.0001). Procedure time for RPS was longer than manual placement (manual: 6.12 min; RPS: 9.7 min; p = 0.0003). Comparison of inter-physician performance during manual placement indicated significant differences in the time taken to complete placements (p = 0.008) and number of repositions (p = 0.04) but not in other study measures (p > 0.05). Comparison of inter-physician performance during RPS-assisted placement suggested statistically significant differences in procedure time (p = 0.02) and not in other study measures (p > 0.05).ConclusionsCT-guided RPS-assisted needle placement reduced radiation dose, number of confirmatory scans, and needle manipulations when compared to manual needle placement by experienced IR physicians, with equivalent accuracy.

  4. Low grade coal worker's pneumoconiosis. Comparison of CT and chest radiography.

    PubMed

    Gevenois, P A; Pichot, E; Dargent, F; Dedeire, S; Vande Weyer, R; De Vuyst, P

    1994-07-01

    We compared CT with chest radiography (CR) in the assessment of low grade coal worker's pneumoconiosis (CWP) in a population of 83 subjects. All subjects had a high-voltage p.a. CR, graded according to the ILO classification between 0/0 and 1/1, a conventional CT (CCT) using contiguous 1-cm-thick sections on the entire thorax and a set of 10 high-resolution CT (HRCT) images. CR and CT were separately read by consensus by 2 teams of 2 trained readers. CR was coded 0/0 in 9 subjects; 0/1 in 31; 1/0 in 28; 1/1 in 15. Among these groups of patients, micronodules were detected by CT in respectively 2 (22%), 14 (45%), 17 (61%) and 10 (67%) patients. In all groups, micronodules were more often detected by CT when the opacities detected on CR were scored as rounded (p, q) than irregular (s, t). Among the patients graded 0/0 or 0/1, CT showed micronodules in 40%. By contrast, among the patients graded 1/0 or 1/1, CT did not show micronodules in 37%, but revealed in numerous patients that opacities detected on CR were related to bronchiectasis and/or emphysema only. Comparative analysis of HRCT and CCT showed that both techniques are complementary and proved the usefulness of CCT in the detection or confirmation of low profusion of micronodules.

  5. Multimodal imaging of the human temporal bone: A comparison of CT and optical scanning techniques

    NASA Astrophysics Data System (ADS)

    Voie, Arne H.; Whiting, Bruce; Skinner, Margaret; Neely, J. Gail; Lee, Kenneth; Holden, Tim; Brunsden, Barry

    2003-10-01

    A collaborative effort between Washington University in St. Louis and Spencer Technologies in Seattle, WA has been undertaken to create a multimodal 3D reconstruction of the human cochlea and vestibular system. The goal of this project is to improve the accuracy of in vivo CT reconstructions of implanted cochleae, and to expand the knowledge of high-resolution anatomical detail provided by orthogonal-plane optical sectioning (OPFOS). At WUSL, computed tomography (CT) images of the cochlea are used to determine the position of cochlear implant electrodes relative to target auditory neurons. The cochlear implant position is determined using pre- and post-operative CT scans. The CT volumes are cross-registered to align the semicircular canals and internal auditory canal, which have a unique configuration in 3-D space. The head of a human body donor was scanned with a clinical CT device, after which the temporal bones were removed, fixed in formalin and trimmed prior to scanning with a laboratory Micro CT scanner. Following CT, the temporal bones were sent to the OPFOS Imaging Lab at Spencer Technologies for a further analysis. 3-D reconstructions of CT and OPFOS imaging modalities were compared, and results are presented. [Work supported by NIDCD Grants R44-03623-5 and R01-00581-13.

  6. A comparison of micro-CT and thin section analysis of Lateglacial glaciolacustrine varves from Glen Roy, Scotland

    NASA Astrophysics Data System (ADS)

    Bendle, Jacob M.; Palmer, Adrian P.; Carr, Simon J.

    2015-04-01

    Despite the prevalence of thin section analysis in studies of Quaternary sediments, there are limitations associated with the production of thin sections (sediment modification) and the inherently 2D view that a thin section affords. Non-destructive and rapid scanning technologies such as X-ray computed microtomography (μCT) enable material samples to be visualised and analysed in 3D. In a Quaternary context, however, such techniques are in their infancy. This paper assesses the optimum approach to μCT analysis of Quaternary sediments, applying the method on Lateglacial glaciolacustrine varves from Glen Roy, Scotland. Scan datasets are examined at each stage of the thin section process and comparisons are made between 2D μCT images and thin sections for the recognition of 2D sediment features, with further appraisal of 3D models to identify 3D sediment structures. Comparable sediment features are observed in 2D μCT images and thin sections, however, the μCT imaging resolution determines the precision of microfacies descriptions. Additional 3D structures are distinguished from volumetric models that are otherwise impossible to identify in thin section slides. These 3D structures can locally alter sediment properties (e.g. layer thickness) as seen in 2D thin sections and/or digital images, although such variation cannot be detected with these media. It has been demonstrated that clear benefits exist in understanding the 3D structure of Quaternary sediments, both prior to thin-sectioning to avoid complicating (e.g. deformation) structures, and after thin-sectioning to establish the complex 3D context of 2D datasets. It is recommended that μCT and thin section techniques are applied in parallel in future studies, which will profit from the integration of 'true' 3D data. It is also advised that samples are scanned soon after field sampling, due to the significant modification of in situ sediment structures that can occur during thin section processing.

  7. Comparison of CT angiography and digital subtraction angiography in the diagnosis of aortic coarctation.

    PubMed

    Miabi, Zinat; Pourfathi, Hojjat; Midia, Mehran; Midia, Ramin; Parvizi, Rezayat

    2011-01-01

    There are several methods for the diagnosis and evaluation of coarctation of the aorta. Digital Subtraction Angiography (DSA) is the standard detection method, though it entails complications and side-effects. The aim of the present study was to compare Computed Tomography (CT) angiography with DSA for diagnosing aortic coarctation. We performed a cross-sectional study of 15 patients (11 males and four females aged between two and 30 years) referred to Tabriz Shahid Madani Hospital and Imaging Center between August 2005 and February 2006 with suspected aortic coarctation. All patients were subjected to DSA and CT angiography for diagnosis of aortic coarctation. The mean age of the patients was 14.6 years; 11 were male (74.4%) and four (26.6%) were female. The DSA and CT angiography results were comparable in all patients in terms of diagnosis and the detection of complications, particularly cardiovascular complications. However, CT angiography was less time-consuming to perform than DSA (p < 0.0001). In conclusion, CT angiography, comparableto DSA, diagnosed coarctation of aorta in all the patients. However, CT angiography is a non-invasive, cost effective procedure that takes significantly less time to carry out than DSA. Therefore, CT angiography is recommended as an appropriate method for diagnosing the coarctation of aorta.

  8. Comparison of two respiration monitoring systems for 4D imaging with a Siemens CT using a new dynamic breathing phantom.

    PubMed

    Vásquez, A C; Runz, A; Echner, G; Sroka-Perez, G; Karger, C P

    2012-05-07

    Four-dimensional computed tomography (4D-CT) requires breathing information from the patient, and for this, several systems are available. Testing of these systems, under realistic conditions, requires a phantom with a moving target and an expandable outer contour. An anthropomorphic phantom was developed to simulate patient breathing as well as lung tumor motion. Using the phantom, an optical camera system (GateCT) and a pressure sensor (AZ-733V) were simultaneously operated, and 4D-CTs were reconstructed with a Siemens CT using the provided local-amplitude-based sorting algorithm. The comparison of the tumor trajectories of both systems revealed discrepancies up to 9.7 mm. Breathing signal differences, such as baseline drift, temporal resolution and noise level were shown not to be the reason for this. Instead, the variability of the sampling interval and the accuracy of the sampling rate value written on the header of the GateCT-signal file were identified as the cause. Interpolation to regular sampling intervals and correction of the sampling rate to the actual value removed the observed discrepancies. Consistently, the introduction of sampling interval variability and inaccurate sampling rate values into the header of the AZ-733V file distorted the tumor trajectory for this system. These results underline the importance of testing new equipment thoroughly, especially if components of different manufacturers are combined.

  9. Comparison of CT and dual-energy DEXA using a modified trunk compartment in the measurement of abdominal fat.

    PubMed

    Lane, James T; Mack-Shipman, Lynn R; Anderson, Joseph C; Moore, Timothy E; Erickson, Judi M; Ford, Timothy C; Stoner, Julie A; Larsen, Jennifer L

    2005-08-01

    The quantification of abdominal fat is a marker of health risk. While dual-energy x-ray absorptiometry (DEXA) is easily applied, it measures overall fat, although abdominal fat may be a better indicator of health risk from obesity. We have evaluated whether a subcomponent of DEXA measurements correlates better with computed tomography (CT) for body fat than those traditionally used. Forty-seven healthy adults (22 M/25 F), aged 54.5+/-15.8 yr (mean+/-SD), with BMI of 27.1+/-4.6 kg/m2 participated in a cross-sectional study. Body fat was measured using abdominal CT and DEXA for total fat, trunk fat, and a modified trunk measurement that excludes the chest, termed "lower trunk," and compared. The coefficient of variation for DEXA measurements for trunk, lower trunk, and total body were 1.98, 3.12, and 0.85%, respectively. Mean DEXA for percentage fat ranged from 31.7% to 34.1% for trunk, lower trunk, and total body, compared to 54.2% for abdominal CT (p<0.003 for each pairwise comparison). Lower trunk, whole trunk, and total body DEXA measurements were not different. Measurement of subcomponents of fat content by DEXA is not superior to whole body measurements and remains consistently lower than measurements by CT.

  10. Comparison of CT and MRI in Diagnosis of Laryngeal Carcinoma with Anterior Vocal Commissure Involvement

    PubMed Central

    Wu, Jian-hui; Zhao, Jing; Li, Zeng-hong; Yang, Wei-qiang; Liu, Qi-hong; Yang, Zhi-yun; Liao, Bing; Li, Xiao-ling; Wang, Bin; Qin, Hao; Luo, Jie; Lv, Ke-xing; Wen, Wei-ping; Lei, Wen-bin

    2016-01-01

    This study aimed to compare the accuracy of CT and MRI in determining the invasion of thyroid cartilage by and the T staging of laryngeal carcinoma with anterior vocal commissure (AVC) involvement. A total of 26 cases of laryngeal carcinomas with AVC involvement from May 2012 to January 2014 underwent enhanced CT and MRI scan, out of whom 6 patients also underwent diffusion-weighted magnetic resonance imaging(DWI). T staging and thyroid cartilage involvement were evaluated. All the surgical specimens underwent serial section and were reviewed by two senior pathologists independently. When compared with pathologic staging, the accuracy was 88.46% (23/26) of MRI scan (with a 95% confidence interval 37~77%) and 57.69% (15/26) of CT scan (with a 95% confidence interval 70~98%), respectively (P < 0.01). We also reported three cases who were misdiagnosed on CT or MRI about either the thyroid cartilage was involved or not, and one case of preliminary study of DWI. Compared to CT, MRI exhibited a higher accuracy rate on T staging of laryngeal carcinomas with AVC involvement. Combined utility of CT and MRI could help improve the accuracy of assessment of thyroid cartilage involvement and T staging of laryngeal carcinomas with AVC involvement. PMID:27480073

  11. Use of CT to reduce understaging in prostatic cancer: comparison with conventional staging techniques

    SciTech Connect

    Emory, T.H.; Reinke, D.B.; Hill, A.L.; Lange, P.H.

    1983-08-01

    Thirty prostatic cancer patients were evaluated for staging purposes with both CT (18-sec scan speed) and certain commonly used conventional diagnostic tests, namely: radionuclide bone scan with correlative plain films, the prostatic fraction of the serum acid phosphatase, excretory urogram, and chest radiograph. All patients included in the study had histopathologic proof of diagnosis. CT correctly identified extracapsular prostatic cancer spread locally or in pelvic lymph nodes in 14% of patients with completely negative conventional studies. Sensitivity of extracapsular tumor spread detection increased from 41% to 59% by adding CT to the conventional studies. CT confirmed the presence of tumor spread and localized it in 43% of patients with positive conventional studies. Conventional studies were positive when tumor spread was present in 32% of patients with negative CT. CT reduces understaging when conventional tests are negative, localizes and conforms tumor spread when conventional tests are positive, but cannot demonstrate tumor spread in some patients whose conventional tests are positive and who are subsequently shown to have tumor spread histopathologically.

  12. Localized Prostate Cancer Detection with 18F FACBC PET/CT: Comparison with MR Imaging and Histopathologic Analysis

    PubMed Central

    Mena, Esther; Shih, Joanna; Pinto, Peter A.; Merino, Maria J.; Lindenberg, Maria L.; Bernardo, Marcelino; McKinney, Yolanda L.; Adler, Stephen; Owenius, Rikard; Choyke, Peter L.; Kurdziel, Karen A.

    2014-01-01

    Purpose To characterize uptake of 1-amino-3-fluorine 18-fluorocyclobutane-1-carboxylic acid (18F FACBC) in patients with localized prostate cancer, benign prostatic hyperplasia (BPH), and normal prostate tissue and to evaluate its potential utility in delineation of intraprostatic cancers in histopathologically confirmed localized prostate cancer in comparison with magnetic resonance (MR) imaging. Materials and Methods Institutional review board approval and written informed consent were obtained for this HIPAA-compliant prospective study. Twenty-one men underwent dynamic and static abdominopelvic 18F FACBC combined positron emission tomography (PET) and computed tomography (CT) and multiparametric (MP) 3-T endorectal MR imaging before robotic-assisted prostatectomy. PET/CT and MR images were coregistered by using pelvic bones as fiducial markers; this was followed by manual adjustments. Whole-mount histopathologic specimens were sliced with an MR-based patient-specific mold. 18F FACBC PET standardized uptake values (SUVs) were compared with those at MR imaging and histopathologic analysis for lesion- and sector-based (20 sectors per patient) analysis. Positive and negative predictive values for each modality were estimated by using generalized estimating equations with logit link function and working independence correlation structure. Results 18F FACBC tumor uptake was rapid but reversible. It peaked 3.6 minutes after injection and reached a relative plateau at 15–20 minutes (SUVmax[15–20min]). Mean prostate tumor SUVmax(15–20min) was significantly higher than that of the normal prostate (4.5 ± 0.5 vs 2.7 ± 0.5) (P < .001); however, it was not significantly different from that of BPH (4.3 ± 0.6) (P = .27). Sector-based comparison with histopathologic analysis, including all tumors, revealed sensitivity and specificity of 67% and 66%, respectively, for 18F FACBC PET/CT and 73% and 79%, respectively, for T2-weighted MR imaging. 18F FACBC PET/CT and MP MR

  13. A Comparison of daily megavoltage CT and ultrasound image guided radiation therapy for prostate cancer

    SciTech Connect

    Peng Cheng; Kainz, Kristofer; Lawton, Colleen; Li, X. Allen

    2008-12-15

    In order to quantify the differences between ultrasound-imaging and megavoltage-CT (MVCT) daily prostate localization in prostate-cancer radiotherapy and their dosimetric impacts, daily shifts were analyzed for a total of 140 prostate cancer patients; 106 positioned using ultrasound-based imaging [B-mode Acquisition and Targeting (BAT)], and 34 using the MVCT from a TomoTherapy Hi-Art unit. The shifts indicated by the two systems were compared statistically along the right/left (R/L), superior/inferior (S/I), and anterior/posterior (A/P) directions. The systematic and random variations among the daily alignments were calculated. Margins to account for these shifts were estimated. The mean shifts and standard deviations along the R/L, S/I, and A/P directions were -0.11{+-}3.80, 0.67{+-}4.67, and 2.71{+-}6.31 mm for BAT localizations and -0.98{+-}5.13, 0.27{+-}3.35, and 1.00{+-}4.22 mm for MVCT localizations, respectively. The systematic and random variations in daily shifts based on MVCT were generally smaller than those based on BAT, especially along the A/P direction. A t-test showed this difference to be statistically significant. The planning target volume margins in the A/P direction estimated to account for daily variations were 8.81 and 14.66 mm based on MVCT and BAT data, respectively. There was no statistically significant difference in the daily prostate movement pattern between the first few fractions and the remaining fractions. Dosimetric comparison of MVCT and BAT prostate alignments was performed for seven fractions from a patient. The degradation from the plan caused by the MVCT alignment is trivial, while that by BAT is substantial. The MVCT technique results in smaller variations in daily shifts than ultrasound imaging, indicating that MVCT is more reliable and precise for prostate localization. Ultrasound-based localization may overestimate the daily prostate motion, particularly in the A/P direction, negatively impacting prostate dose coverage

  14. Iofetamine HCI I-123 brain scanning in stroke: a comparison with transmission CT

    SciTech Connect

    Park, C.H.; Madsen, M.T.; McLellan, T.; Schwartzman, R.J.

    1988-03-01

    Although IMP scans fail to show fine anatomical details of the brain, because of poor resolution of a single head rotational system, adequate information is offered by the scans to localize most perfusion defects caused by stroke. The following conclusions can be drawn from our study: 1. The planar IMP brain scans processed through the computer are sensitive in the early diagnosis of acute stroke except for small and deeply localized lesions. 2. The SPECT IMP imaging is more sensitive than the planar or transmission CT scans in the early diagnosis of stroke. Semiquantitative evaluations are feasible with IMP SPECT. 3. Neither transmission CT nor IMP SPECT are sensitive in the detection of acute lacunar infarcts. 4. In acute infarction, the transmission CT is usually negative or minimally positive in the early stages, while impaired uptake of IMP occurs immediately after the onset of the stroke. In acute stroke, the extent of the perfusion defect on IMP is usually greater than the abnormality seen on the transmission CT. 5. On followup studies, IMP scans show improved perfusion reflecting physiologic changes, while transmission CT scans show further dense anatomical changes when compared to the initial studies. 6. Hyperemic changes are likely due to collateral circulation or luxury perfusion. This finding suggests that the IMP reflects local cerebral blood flow in strokes.

  15. A quantitative comparison of micro-CT preparations in Dipteran flies

    PubMed Central

    Swart, Peter; Wicklein, Martina; Sykes, Dan; Ahmed, Farah; Krapp, Holger G.

    2016-01-01

    X-ray-based 3D-imaging techniques have gained fundamental significance in research areas ranging from taxonomy to bioengineering. There is demand for the characterisation of species-specific morphological adaptations, micro-CTCT) being the method of choice in small-scale animals. This has driven the development of suitable staining techniques to improve absorption-based tissue contrast. A quantitative account on the limits of current staining protocols for preparing μCT specimen, however, is still missing. Here we present a study that quantifies results obtained by combining a variety of different contrast agents and fixative treatments that provides general guidance for μCT applications, particularly suitable for insect species. Using a blowfly model system (Calliphora), we enhanced effective spatial resolution and, in particular, optimised tissue contrast enabling semi-automated segmentation of soft and hard tissue from μCT data. We introduce a novel probabilistic measure of the contrast between tissues: PTC. Our results show that a strong iodine solution provides the greatest overall increase in tissue contrast, however phosphotungstic acid offers better inter-tissue discriminability. We further show that using paraformaldehyde as a fixative as opposed to ethanol, slows down the uptake of a staining solution by approximately a factor of two. PMID:28000717

  16. Comparison of CT and MRI brain tumor imaging using a canine glioma model.

    PubMed

    Whelan, H T; Clanton, J A; Wilson, R E; Tulipan, N B

    1988-01-01

    A canine gliosarcoma model was used to study the effectiveness of magnetic resonance imaging (MRI) with gadolinium contrast enhancement in defining the histologic margins of brain tumors. The effectiveness of this technique was compared to conventional computed tomography (CT) using iodinated contrast enhancement. Cultured canine gliosarcoma cells were injected into the left hemisphere of adult mongrel dogs. The dogs developed brain tumors and progressive clinical signs. Serial MRI with and without gadolinium diethylene triamine penta-acetic acid was compared to serial CT with and without sodium iothalamate obtained on the same days. After the final scans, animals were sacrificed; the brains were removed and processed for routine histopathologic study. All tumors were visualized with contrast-enhanced MRI which proved most sensitive. Gadolinium di-ethylene triamine penta-acetic acid caused bright enhancement of tumors in a distribution that consistently corresponded to areas of pathologically proved tumor infiltration. Gross and microscopic autopsy findings correlated better with MRI than with CT which tended to produce poorer resolution and underrepresent the size of viable tumor. Gadolinium-enhanced MRI is more accurate than unenhanced MRI, unenhanced CT, or enhanced CT in defining the histologic margins of tumors.

  17. Performance comparison between static and dynamic cardiac CT on perfusion quantitation and patient classification tasks

    NASA Astrophysics Data System (ADS)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

    2015-03-01

    Cardiac CT acquisitions for perfusion assessment can be performed in a dynamic or static mode. In this simulation study, we evaluate the relative classification and quantification performance of these modes for assessing myocardial blood flow (MBF). In the dynamic method, a series of low dose cardiac CT acquisitions yields data on contrast bolus dynamics over time; these data are fit with a model to give a quantitative MBF estimate. In the static method, a single CT acquisition is obtained, and the relative CT numbers in the myocardium are used to infer perfusion states. The static method does not directly yield a quantitative estimate of MBF, but these estimates can be roughly approximated by introducing assumed linear relationships between CT number and MBF, consistent with the ways such images are typically visually interpreted. Data obtained by either method may be used for a variety of clinical tasks, including 1) stratifying patients into differing categories of ischemia and 2) using the quantitative MBF estimate directly to evaluate ischemic disease severity. Through simulations, we evaluate the performance on each of these tasks. The dynamic method has very low bias in MBF estimates, making it particularly suitable for quantitative estimation. At matched radiation dose levels, ROC analysis demonstrated that the static method, with its high bias but generally lower variance, has superior performance in stratifying patients, especially for larger patients.

  18. Comparison of CT and angiography in assessing resectability of pancreatic carcinoma

    SciTech Connect

    Jafri, S.Z.H.; Aisen, A.M.; Glazer, G.M.; Weiss, C.A.

    1984-03-01

    A retrospective study of 27 patients with pancreatic carcinoma compared computed tomography (CT) and angiography in their ability to predict resectability of the neoplasm, using encasement of the splanchnic vessels as the criterion for nonresectability. Five patients had resectable tumor at surgery; the other 22 had unresectable disease. Tumor involvement of the splanchnic vessels was determined in 18 patients by CT examination and in 19 patients by angiography. Several other patients were found to have liver metastases, resulting in a radiologic diagnosis of nonresectability in 20 patients overall. All patients considered to have unresectable disease on the basis of either radiologic method proved to have unresectable tumor at surgery. CT is about as accurate as angiography in assessing resectability of pancreatic carcinoma.

  19. Acceptance of Combined Coronary CT Angiography and Myocardial CT Perfusion versus Conventional Coronary Angiography in Patients with Coronary Stents—Intraindividual Comparison

    PubMed Central

    Martus, Peter; Laule, Michael; Dewey, Marc; Schönenberger, Eva

    2015-01-01

    Objectives To evaluate how well patients with coronary stents accept combined coronary computed tomography angiography (CTA) and myocardial CT perfusion (CTP) compared with conventional coronary angiography (CCA). Background While combined CTA and CTP may improve diagnostic accuracy compared with CTA alone, patient acceptance of CTA/CTP remains to be defined. Methods A total of 90 patients with coronary stents prospectively underwent CTA/CTP (both with contrast agent, CTP with adenosine) and CCA as part of the CARS-320 study. In this group, an intraindividual comparison of patient acceptance of CTA, CTP, and CCA was performed. Results CTP was experienced to be significantly more painful than CTA (p<0.001) and was associated with a higher frequency of dyspnea (p<0.001). Comparison of CTA/CTP with CCA revealed no significant differences in terms of pain (p = 0.141) and comfort (p = 0.377). Concern before CTA/CTP and CCA and overall satisfaction were likewise not significantly different (p = 0.097 and p = 0.123, respectively). Nevertheless, about two thirds (n = 60, 68%) preferred CTA/CTP to CCA (p<0.001). Moreover, patients felt less helpless during CTA/CTP than during CCA (p = 0.026). Lack of invasiveness and absence of pain were the most frequently mentioned advantages of CTA/CTP over CCA in our patient population. Conclusions CCA and combined CTA/CTP are equally well accepted by patients; however, more patients prefer CTA/CTP. CTP was associated with more intense pain than CTA and more frequently caused dyspnea than CTA alone. Trial Registration ClinicalTrials.gov NCT00967876 PMID:26327127

  20. Chest CT Features of Cystic Fibrosis in Korea: Comparison with Non-Cystic Fibrosis Diseases

    PubMed Central

    Yang, So Yeon; Cha, Min Jae; Kim, Tae Jung; Kim, Tae Sung; Yoon, Hyun Jung

    2017-01-01

    Objective Cystic fibrosis (CF) is a rare congenital disease in Korea, and its clinical and imaging findings are unclear. The objective of our study was to describe the clinical and CT features of CF in Korea and compare its features with those of other diseases mimicking CF. Materials and Methods From November 1994 to December 2014, a presumptive diagnosis of CF was made in 23 patients based on clinical or radiological examination. After the exclusion of 10 patients without diagnostic confirmation, 13 patients were included in the study. A diagnosis of CF was made with the CF gene study. CT findings were evaluated for the presence and distribution of parenchymal abnormalities including bronchiectasis, tree-in-bud (TIB) pattern, mucus plugging, consolidation, and mosaic attenuation. Results Of the 13 patients, 7 (median age, 15 years) were confirmed as CF, 4 (median age, 19 years) had primary ciliary dyskinesia, 1 had bronchiectasis of unknown cause, and 1 had chronic asthma. CT of patients with CF showed bilateral bronchiectasis, TIB pattern, mosaic attenuation, and mucus plugging in all patients, with upper lung predominance (57%). In CT of the non-CF patients, bilateral bronchiectasis, TIB pattern, mosaic attenuation, and mucus plugging were also predominant features, with lower lung predominance (50%). Conclusion Korean patients with CF showed bilateral bronchiectasis, cellular bronchiolitis, mucus plugging, and mosaic attenuation, which overlapped with those of non-CF patients. CF gene study is recommended for the definitive diagnosis of CF in patients with these clinical and imaging features. PMID:28096734

  1. Mucinous versus nonmucinous solitary pulmonary nodular bronchioloalveolar carcinoma: CT and FDG PET findings and pathologic comparisons.

    PubMed

    Lee, Ho Yun; Lee, Kyung Soo; Han, Joungho; Kim, Byung-Tae; Cho, Young-Seok; Shim, Young Mog; Kim, Jhingook

    2009-08-01

    We aimed to evaluate the CT, PET, and pathologic findings of solitary pulmonary nodular mucinous and nonmucinous bronchioloalveolar carcinomas (BACs). From August 2003 to March 2008, we saw 24 patients with solitary pulmonary nodular mucinous (n=6) or nonmucinous (n=18) BACs that were resected. CT and PET findings of the lesions were assessed in terms of size, solidity, morphologic characteristics, attenuation and maximum standardized uptake value (mSUV). All nonmucinous BACs appeared as a pure ground-glass opacity (GGO) nodule, whereas mucinous BACs appeared as solid (n=4) or part-solid (n=2) nodules. CT attenuation values were significantly higher for mucinous BACs (-21.0 HU+/-4.9) than for nonmucinous BACs (-491.8 HU+/-172.5) (P<.001). Mean mSUVs were 2.3+/-1.9 for mucinous BACs and 0.5+/-0.8 for nonmucinous BACs (P=.007), but mSUVs were not statistically different after size adjustment (r=0.371, P=.081). Mucinous BACs appear as solid or part-solid nodules at CT, whereas nonmucinous BACs present as pure GGO nodules. Both subtypes of tumors show scant FDG uptake at PET.

  2. Comparison of SNOMED CT versus Medcin Terminology Concept Coverage for Mild Traumatic Brain Injury

    PubMed Central

    Montella, Diane; Brown, Steven H.; Elkin, Peter L.; Jackson, James C.; Rosenbloom, S. Trent; Wahner-Roedler, Dietlind; Welsh, Gail; Cotton, Bryan; Guillamondegui, Oscar D.; Lew, Henry; Taber, Katherine H.; Tupler, Larry A.; Vanderploeg, Rodney; Speroff, Theodore

    2011-01-01

    Background: Traumatic Brain Injury (TBI) is a “signature” injury of the current wars in Iraq and Afghanistan. Structured electronic data regarding TBI findings is important for research, population health and other secondary uses but requires appropriate underlying standard terminologies to ensure interoperability and reuse. Currently the U.S. Department of Veterans Affairs (VA) uses the terminology SNOMED CT and the Department of Defense (DOD) uses Medcin. Methods: We developed a comprehensive case definition of mild TBI composed of 68 clinical terms. Using automated and manual techniques, we evaluated how well the mild TBI case definition terms could be represented by SNOMED CT and Medcin, and compared the results. We performed additional analysis stratified by whether the concepts were rated by a TBI expert panel as having High, Medium, or Low importance to the definition of mild TBI. Results: SNOMED CT sensitivity (recall) was 90% overall for coverage of mild TBI concepts, and Medcin sensitivity was 49%, p < 0.001 (using McNemar’s chi square). Positive predictive value (precision) for each was 100%. SNOMED CT outperformed Medcin for concept coverage independent of import rating by our TBI experts. Discussion: SNOMED CT was significantly better able to represent mild TBI concepts than Medcin. This finding may inform data gathering, management and sharing, and data exchange strategies between the VA and DOD for active duty soldiers and veterans with mild TBI. Since mild TBI is an important condition in the civilian population as well, the current study results may be useful also for the general medical setting. PMID:22195156

  3. Comparison of two types of adult phantoms in terms of organ doses from diagnostic CT procedures

    NASA Astrophysics Data System (ADS)

    Liu, Haikuan; Gu, Jianwei; Caracappa, Peter F.; Xu, X. George

    2010-03-01

    The rapidly increasing number of diagnostic computed tomography (CT) procedures in the recent decades has spurred heightened concern over the potential risk to patients. Although an accurate organ dose assessment tool has now become highly desirable, existing software packages depend on stylized computational phantoms that were originally developed more than 40 years ago, exhibiting very large discrepancies when compared with phantoms that are anatomically realistic. However, past comparative studies did not focus on CT protocols for adult patients. This study was designed to quantitatively compare two types of phantoms, the stylized phantoms and a pair of recently developed RPI-adult male and adult female (RPI-AM and RPI-AF) phantoms, for various CT scanning protocols involving the chest, abdomen-pelvis and chest-abdomen-pelvis. Organ doses were based on Monte Carlo simulations using the MCNPX code and a detailed CT scanner model for the GE LightSpeed 16. Results are presented as ratios of organ doses from the stylized phantoms to those from the RPI phantoms. It is found that, for most organs contained in the scan volume, the ratios were within the range of 0.75-1.16. However, the stomach doses are significantly different and the ratio is found to be up to 1.86 in male phantoms and 2.29 in the female phantoms due to the anatomical differences between the two types of phantoms. Organs that lie near a scan boundary also exhibit a significant relative difference in organ doses between the two types of phantoms. This study concludes that, due to relatively low x-ray energies, CT doses are very sensitive to organ shape, size and position, and thus anatomically realistic phantoms should be used to avoid the dose uncertainties caused by the lack of anatomical realism. The new phantoms, such as the RPI-AM and AF phantoms that are designed using advanced surface meshes, are deformable and will make it possible to match the anatomy of a specific patient leading to further

  4. Comparison of DCE-CT models for quantitative evaluation of Ktrans in larynx tumors

    NASA Astrophysics Data System (ADS)

    Oosterbroek, J.; Bennink, E.; Philippens, M. E. P.; Raaijmakers, C. P. J.; Viergever, M. A.; de Jong, H. W. A. M.

    2015-05-01

    Dynamic contrast enhanced CT (DCE-CT) can be used to estimate blood perfusion and vessel permeability in tumors. Tumor induced angiogenesis is generally associated with disorganized microvasculature with increased permeability or leakage. Estimated vascular leakage (Ktrans) values and their reliability greatly depend on the perfusion model used. To identify the preferred model for larynx tumor analysis, several perfusion models frequently used for estimating permeability were compared in this study. DCE-CT scans were acquired for 16 larynx cancer patients. Larynx tumors were delineated based on whole-mount histopathology after laryngectomy. DCE-CT data within these delineated volumes were analyzed using the Patlak and Logan plots, the Extended Tofts Model (ETM), the Adiabatic Approximation to the Tissue Homogeneity model (AATH) and a variant of AATH with fixed transit time (AATHFT). Akaike’s Information Criterion (AIC) was used to identify the best fitting model. Ktrans values from all models were compared with this best fitting model. Correlation strength was tested with two-tailed Spearman’s rank correlation and further examined using Bland-Altman plots. AATHFT was found to be the best fitting model. The overall median of individual patient medians Ktrans estimates were 14.3, 15.1, 16.1, 2.6 and 22.5 mL/100 g min  -  1 for AATH, AATHFT, ETM, Patlak and Logan, respectively. Ktrans estimates for all models except Patlak were strongly correlated (P  <  0.001). Bland-Altman plots show large biases but no significant deviating trend for any model other than Patlak. AATHFT was found to be the preferred model among those tested for estimation of Ktrans in larynx tumors.

  5. The relevance of MRI for patient modeling in head and neck hyperthermia treatment planning: A comparison of CT and CT-MRI based tissue segmentation on simulated temperature

    SciTech Connect

    Verhaart, René F. Paulides, Margarethus M.; Fortunati, Valerio; Walsum, Theo van; Veenland, Jifke F.; Lugt, Aad van der

    2014-12-15

    Purpose: In current clinical practice, head and neck (H and N) hyperthermia treatment planning (HTP) is solely based on computed tomography (CT) images. Magnetic resonance imaging (MRI) provides superior soft-tissue contrast over CT. The purpose of the authors’ study is to investigate the relevance of using MRI in addition to CT for patient modeling in H and N HTP. Methods: CT and MRI scans were acquired for 11 patients in an immobilization mask. Three observers manually segmented on CT, MRI T1 weighted (MRI-T1w), and MRI T2 weighted (MRI-T2w) images the following thermo-sensitive tissues: cerebrum, cerebellum, brainstem, myelum, sclera, lens, vitreous humor, and the optical nerve. For these tissues that are used for patient modeling in H and N HTP, the interobserver variation of manual tissue segmentation in CT and MRI was quantified with the mean surface distance (MSD). Next, the authors compared the impact of CT and CT and MRI based patient models on the predicted temperatures. For each tissue, the modality was selected that led to the lowest observer variation and inserted this in the combined CT and MRI based patient model (CT and MRI), after a deformable image registration. In addition, a patient model with a detailed segmentation of brain tissues (including white matter, gray matter, and cerebrospinal fluid) was created (CT and MRI{sub db}). To quantify the relevance of MRI based segmentation for H and N HTP, the authors compared the predicted maximum temperatures in the segmented tissues (T{sub max}) and the corresponding specific absorption rate (SAR) of the patient models based on (1) CT, (2) CT and MRI, and (3) CT and MRI{sub db}. Results: In MRI, a similar or reduced interobserver variation was found compared to CT (maximum of median MSD in CT: 0.93 mm, MRI-T1w: 0.72 mm, MRI-T2w: 0.66 mm). Only for the optical nerve the interobserver variation is significantly lower in CT compared to MRI (median MSD in CT: 0.58 mm, MRI-T1w: 1.27 mm, MRI-T2w: 1.40 mm

  6. CT and MR findings of Krukenberg tumors: Comparison with primary ovarian tumors

    SciTech Connect

    Kim, Seung Hyup; Kim, Won Hong; Park, Kyung Joo

    1996-05-01

    The purposes of this study were to evaluate the CT and MR findings of Krukenberg tumors and to compare them with those of primary ovarian tumors. This study included 20 patients with Krukenberg tumors and 65 patients with various primary ovarian tumors. CT/MR/both imaging studies were available in 15/1/4 patients with Krukenberg tumor and 31/10/24 patients with primary ovarian tumors, respectively. Imaging findings of the tumors were categorized into three subgroups: a solid mass with intratumoral cysts, a solid mass without intratumoral cysts, and a predominantly cystic mass. Among 32 Krukenberg tumors (bilateral in 12 patients), 22 were solid masses with intratumoral cysts, in 14 of which the wall of the intratumoral cysts showed apparently strong contrast enhancement on CT and/or MRI. Six Krukenberg tumors were solid masses without intratumoral cysts, and four were predominantly cystic masses. Imaging findings of 88 primary ovarian tumors (bilateral in 23 patients) were 5 solid masses with intratumoral cysts, 27 solid masses without intratumoral cysts, and 56 predominantly cystic masses. None of the five primary ovarian tumors with solid mass with intratumoral cysts demonstrated apparently strong contrast enhancement of the cyst wall. Krukenberg tumor should be suspected when one sees solid ovarian tumors containing well demarcated intratumoral cystic lesions, especially if the walls of those cysts demonstrate apparently strong contrast enhancement. 11 refs., 4 figs., 1 tab.

  7. Comparison between clinical, ultrasound, CT, MRI, and pathology findings in dogs presented for suspected thyroid carcinoma.

    PubMed

    Taeymans, Olivier; Penninck, Dominique G; Peters, Rachel M

    2013-01-01

    This study compares clinical, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and pathology findings in 16 prospectively, and seven retrospectively recruited dogs presented for suspected thyroid carcinoma. Of these, 17 were confirmed thyroid carcinoma, while six were initially misdiagnosed. These included four carotid body tumors, one para-esophageal abscess, and one undifferentiated squamous cell carcinoma. Thyroid carcinomas occurred in older dogs without evidence of sex predilection, and were more often unilateral. All were large, heterogeneous, moderately to strongly vascularized, and most commonly contained areas of dystrophic mineralization and/or fluid accumulations. On MRI, thyroid carcinomas appeared hyperintense compared to surrounding musculature in all imaging sequences used, while on CT they had a lower attenuation value than normal thyroid gland tissue. Histologically confirmed tumor capsule disruption with invasion of the surrounding structures was most commonly detected with MRI. Palpation was not an accurate predictor of locally invasive vs. well-encapsulated masses. Computed tomography had the highest specificity (100%) and MRI had the highest sensitivity (93%) in diagnosing thyroid carcinoma, while ultrasound had considerably lower results. We conclude that ultrasound is adequate for use as a screening tool for dogs with suspected thyroid carcinoma, but recommend either CT or MRI for preoperative diagnosis and staging.

  8. A Comparison between 18F-FDG PET/CT Imaging and Biological and Radiological Findings in Restaging of Hepatoblastoma Patients

    PubMed Central

    Treglia, Giorgio; Pagano, Manuela; Fania, Piercarlo; Basso, Maria Eleonora; Fagioli, Franca; Ficola, Umberto

    2013-01-01

    Background. In this study we retrospectively evaluated if 18F-FDG-PET/CT provided incremental diagnostic information over CI in a group of hepatoblastoma patients performing restaging. Procedure. Nine patients (mean age: 5.9 years; range: 3.1–12 years) surgically treated for hepatoblastoma were followed up by clinical examination, serum α-FP monitoring, and US. CI (CT or MRI) and PET/CT were performed in case of suspicion of relapse. Fine-needle aspiration biopsies (FNAB) were carried out for final confirmation if the results of CI, PET/CT, and/or α-FP levels were suggestive of relapse. PET/CT and CI findings were analyzed for comparison purposes, using FNAB as reference standard. Results. α-FP level was suggestive of disease recurrence in 8/9 patients. Biopsy was performed in 8/9 cases. CI and PET/CT resulted to be concordant in 5/9 patients (CI identified recurrence of disease, but 18F-FDG-PET/CT provided a better definition of disease extent); in 4/9 cases, CI diagnostic information resulted in negative findings, whereas PET/CT correctly detected recurrence of disease. 18F-FDG-PET/CT showed an agreement of 100% (8/8) with FNAB results. Conclusions. 18F-FDG-PET/CT scan seems to better assess HB patients with respect to CI and may provide incremental diagnostic value in the restaging of this group of patients. PMID:24063012

  9. MRI experience with multiple sclerosis - Comparison to CT and clinical status

    SciTech Connect

    Reese, L.; Carr, T.; Nicholson, R.L.

    1985-05-01

    A Multiple Sclerosis (M.S.) Protocol was set--SEB (1000/60) volume acquisition and selected single slices SEC (1000/120) and IR (1500/450). Single slices SE 500/30, 1500/30 and 1530/60 were obtained for T1 and T2 calculation. New software and coils permitted multi-slice multi-echo acquisition so the Protocol was changed to multi-slice multi-echo transaxial SE 2120/60-120, and the T1 and T2 sets. The study consisted of 62 known M.S. patients and 35 controls. Of the 62 M.S. patients, 58 (94%) were positive on NMR. Thirty-two of these patients had CT scans of which 17 (53%) were positive. Of the 35 controls, 2 were positive on NMR for a false positive rate of 6%. The relative sensitivity of NMR, Double Dose Delayed CT(DDD) and contrast CT in the clinically early progressive group is 87%, 60% and 45% respectively. In the chronic stable group, the sensitivity is 100% for NMR and 55% for DDD. The NMR lesions were graded on a scale of 1 - 4 and the authors found poor correlation with either duration of disease or Kurtzke Functional Scale. The T1, T2 values showed good differentiation between white matter and lesions, although differentiation between lesions and grey matter was poor. White matter has T1 of 328 +- 28 and T2 of 85 +- 22, grey matter T1 of 515 +- 37 and T2 of 96 +- 32 and lesions T1 of 530 +- 76 and T2 of 106 +- 27. They conclude that multi-slice SE 2120/60-120 NMR imaging has proven to be a valuable tool in the clinical diagnosis of Multiple Sclerosis. Most of the lesions seen are asymptomatic and the number, size and distribution of lesions have little correlation with severity or acuity of the disease.

  10. Comparison of measured and estimated maximum skin doses during CT fluoroscopy lung biopsies

    SciTech Connect

    Zanca, F.; Jacobs, A.; Crijns, W.; De Wever, W.

    2014-07-15

    Purpose: To measure patient-specific maximum skin dose (MSD) associated with CT fluoroscopy (CTF) lung biopsies and to compare measured MSD with the MSD estimated from phantom measurements, as well as with the CTDIvol of patient examinations. Methods: Data from 50 patients with lung lesions who underwent a CT fluoroscopy-guided biopsy were collected. The CT protocol consisted of a low-kilovoltage (80 kV) protocol used in combination with an algorithm for dose reduction to the radiology staff during the interventional procedure, HandCare (HC). MSD was assessed during each intervention using EBT2 gafchromic films positioned on patient skin. Lesion size, position, total fluoroscopy time, and patient-effective diameter were registered for each patient. Dose rates were also estimated at the surface of a normal-size anthropomorphic thorax phantom using a 10 cm pencil ionization chamber placed at every 30°, for a full rotation, with and without HC. Measured MSD was compared with MSD values estimated from the phantom measurements and with the cumulative CTDIvol of the procedure. Results: The median measured MSD was 141 mGy (range 38–410 mGy) while the median cumulative CTDIvol was 72 mGy (range 24–262 mGy). The ratio between the MSD estimated from phantom measurements and the measured MSD was 0.87 (range 0.12–4.1) on average. In 72% of cases the estimated MSD underestimated the measured MSD, while in 28% of the cases it overestimated it. The same trend was observed for the ratio of cumulative CTDIvol and measured MSD. No trend was observed as a function of patient size. Conclusions: On average, estimated MSD from dose rate measurements on phantom as well as from CTDIvol of patient examinations underestimates the measured value of MSD. This can be attributed to deviations of the patient's body habitus from the standard phantom size and to patient positioning in the gantry during the procedure.

  11. Quantitative assessment of emphysema from whole lung CT scans: comparison with visual grading

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Apanosovich, Tatiyana V.; Wang, Jianwei; Yankelevitz, David F.; Henschke, Claudia I.

    2009-02-01

    Emphysema is a disease of the lungs that destroys the alveolar air sacs and induces long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema and for visual assessment by radiologists of the extent present in the lungs. Several measures have been introduced for the quantification of the extent of disease directly from CT data in order to add to the qualitative assessments made by radiologists. In this paper we compare emphysema index, mean lung density, histogram percentiles, and the fractal dimension to visual grade in order to evaluate the predictability of radiologist visual scoring of emphysema from low-dose CT scans through quantitative scores, in order to determine which measures can be useful as surrogates for visual assessment. All measures were computed over nine divisions of the lung field (whole lung, individual lungs, and upper/middle/lower thirds of each lung) for each of 148 low-dose, whole lung scans. In addition, a visual grade of each section was also given by an expert radiologist. One-way ANOVA and multinomial logistic regression were used to determine the ability of the measures to predict visual grade from quantitative score. We found that all measures were able to distinguish between normal and severe grades (p<0.01), and between mild/moderate and all other grades (p<0.05). However, no measure was able to distinguish between mild and moderate cases. Approximately 65% prediction accuracy was achieved from using quantitative score to predict visual grade, with 73% if mild and moderate cases are considered as a single class.

  12. A comparison of simulation tools for photon-counting spectral CT

    NASA Astrophysics Data System (ADS)

    Nasirudin, Radin A.; Penchev, Petar; Mei, Kai; Rummeny, Ernst J.; Fiebich, Martin; Noël, Peter B.

    2014-03-01

    Photon-counting detectors (PCD) not only have the advantage of providing spectral information but also offer high quantum efficiencies, producing high image quality in combination with a minimal amount of radiation dose. Due to the clinical unavailability of photon-counting CT, the need to evaluate different CT simulation tools for researching different applications for photon-counting systems is essential. In this work, we investigate two different methods to simulate PCD data: Monte-Carlo based simulation (MCS) and analytical based simulation (AS). The MCS is a general-purpose photon transport simulation based on EGSnrc C++ class library. The AS uses analytical forward-projection in combination with additional acquisition parameters. MCS takes into account all physical effects, but is computationally expensive (several days per CT acquisition). AS is fast (several minutes), but lacks the accurateness of MCS with regard to physical interactions. To evaluate both techniques an entrance spectra of 100kvp, a modified CTP515 module of the CatPhan 600 phantom, and a detector system with six thresholds was simulated. For evaluation the simulated projection data are decomposed via a maximum likelihood technique, and reconstructed via standard filtered-back projection (FBP). Image quality from both methods is subjectively and objectively assessed. Visually, the difference in the image quality was not significant. When further evaluated, the relative difference was below 4%. As a conclusion, both techniques offer different advantages, while at different stages of development the accelerated calculations via AS can make a significant difference. For the future one could foresee a combined method to join accuracy and speed.

  13. Skeletal dosimetry based on µCT images of trabecular bone: update and comparisons

    NASA Astrophysics Data System (ADS)

    Kramer, R.; Cassola, V. F.; Vieira, J. W.; Khoury, H. J.; de Oliveira Lira, C. A. B.; Robson Brown, K.

    2012-06-01

    Two skeletal dosimetry methods using µCT images of human bone have recently been developed: the paired-image radiation transport (PIRT) model introduced by researchers at the University of Florida (UF) in the US and the systematic-periodic cluster (SPC) method developed by researchers at the Federal University of Pernambuco in Brazil. Both methods use µCT images of trabecular bone (TB) to model spongiosa regions of human bones containing marrow cavities segmented into soft tissue volumes of active marrow (AM), trabecular inactive marrow and the bone endosteum (BE), which is a 50 µm thick layer of marrow on all TB surfaces and on cortical bone surfaces next to TB as well as inside the medullary cavities. With respect to the radiation absorbed dose, the AM and the BE are sensitive soft tissues for the induction of leukaemia and bone cancer, respectively. The two methods differ mainly with respect to the number of bone sites and the size of the µCT images used in Monte Carlo calculations and they apply different methods to simulate exposure from radiation sources located outside the skeleton. The PIRT method calculates dosimetric quantities in isolated human bones while the SPC method uses human bones embedded in the body of a phantom which contains all relevant organs and soft tissues. Consequently, the SPC method calculates absorbed dose to the AM and to the BE from particles emitted by radionuclides concentrated in organs or from radiation sources located outside the human body in one calculation step. In order to allow for similar calculations of AM and BE absorbed doses using the PIRT method, the so-called dose response functions (DRFs) have been developed based on absorbed fractions (AFs) of energy for electrons isotropically emitted in skeletal tissues. The DRFs can be used to transform the photon fluence in homogeneous spongiosa regions into absorbed dose to AM and BE. This paper will compare AM and BE AFs of energy from electrons emitted in skeletal

  14. A comparison of x-ray detectors for mouse CT imaging

    NASA Astrophysics Data System (ADS)

    Goertzen, Andrew L.; Nagarkar, Vivek; Street, Robert A.; Paulus, Michael J.; Boone, John M.; Cherry, Simon R.

    2004-12-01

    There is significant interest in using computed tomography (CT) for in vivo imaging applications in mouse models of disease. Most commercially available mouse x-ray CT scanners utilize a charge-coupled device (CCD) detector coupled via fibre optic taper to a phosphor screen. However, there has been little research to determine if this is the optimum detector for the specific task of in vivo mouse imaging. To investigate this issue, we have evaluated four detectors, including an amorphous selenium (a-Se) detector, an amorphous silicon (a-Si) detector with a gadolinium oxysulphide (GOS) screen, a CCD with a 3:1 fibre taper and a GOS screen, and a CCD with a 2:1 fibre taper and both GOS and thallium-doped caesium iodide (CsI:Tl) screens. The detectors were evaluated by measuring the modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), stability over multiple exposures, and noise in reconstructed CT images. The a-Se detector had the best MTF and the highest DQE (0.6 at 0 lp mm-1) but had the worst stability (45% reduction after 2000 exposure frames). The a-Si detector and the CCD with the 3:1 fibre, both of which used the GOS screen, had very similar performance with a DQE of approximately 0.30 at 0 lp mm-1. For the CCD with the 2:1 fibre, the CsI:Tl screen resulted in a nearly two-fold improvement in DQE over the GOS screen (0.4 versus 0.24 at 0 lp mm-1). The CCDs both had the best stability, with less than a 1% change in pixel values over multiple exposures. The pixel values of the a-Si detector increased 5% over multiple exposures due to the effects of image lag. Despite the higher DQE of the a-Se detector, the reconstructed CT images acquired with the a-Si detector had lower noise levels, likely due to the blurring effects from the phosphor screen.

  15. A comparison of x-ray detectors for mouse CT imaging.

    PubMed

    Goertzen, Andrew L; Nagarkar, Vivek; Street, Robert A; Paulus, Michael J; Boone, John M; Cherry, Simon R

    2004-12-07

    There is significant interest in using computed tomography (CT) for in vivo imaging applications in mouse models of disease. Most commercially available mouse x-ray CT scanners utilize a charge-coupled device (CCD) detector coupled via fibre optic taper to a phosphor screen. However, there has been little research to determine if this is the optimum detector for the specific task of in vivo mouse imaging. To investigate this issue, we have evaluated four detectors, including an amorphous selenium (a-Se) detector, an amorphous silicon (a-Si) detector with a gadolinium oxysulphide (GOS) screen, a CCD with a 3:1 fibre taper and a GOS screen, and a CCD with a 2:1 fibre taper and both GOS and thallium-doped caesium iodide (CsI:Tl) screens. The detectors were evaluated by measuring the modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), stability over multiple exposures, and noise in reconstructed CT images. The a-Se detector had the best MTF and the highest DQE (0.6 at 0 lp mm(-1)) but had the worst stability (45% reduction after 2000 exposure frames). The a-Si detector and the CCD with the 3:1 fibre, both of which used the GOS screen, had very similar performance with a DQE of approximately 0.30 at 0 lp mm(-1). For the CCD with the 2:1 fibre, the CsI:Tl screen resulted in a nearly two-fold improvement in DQE over the GOS screen (0.4 versus 0.24 at 0 lp mm(-1)). The CCDs both had the best stability, with less than a 1% change in pixel values over multiple exposures. The pixel values of the a-Si detector increased 5% over multiple exposures due to the effects of image lag. Despite the higher DQE of the a-Se detector, the reconstructed CT images acquired with the a-Si detector had lower noise levels, likely due to the blurring effects from the phosphor screen.

  16. Performance comparison of two commercial BGO-based PET/CT scanners using NEMA NU 2-2001

    SciTech Connect

    Bolard, Gregory; Prior, John O.; Modolo, Luca; Bischof Delaloye, Angelika; Kosinski, Marek; Wastiel, Claude; Malterre, Jerome; Bulling, Shelley; Bochud, Francois; Verdun, Francis R.

    2007-07-15

    Combined positron emission tomography and computed tomography (PET/CT) scanners play a major role in medicine for in vivo imaging in an increasing number of diseases in oncology, cardiology, neurology, and psychiatry. With the advent of short-lived radioisotopes other than {sup 18}F and newer scanners, there is a need to optimize radioisotope activity and acquisition protocols, as well as to compare scanner performances on an objective basis. The Discovery-LS (D-LS) was among the first clinical PET/CT scanners to be developed and has been extensively characterized with older National Electrical Manufacturer Association (NEMA) NU 2-1994 standards. At the time of publication of the latest version of the standards (NU 2-2001) that have been adapted for whole-body imaging under clinical conditions, more recent models from the same manufacturer, i.e., Discovery-ST (D-ST) and Discovery-STE (D-STE), were commercially available. We report on the full characterization both in the two- and three-dimensional acquisition mode of the D-LS according to latest NEMA NU 2-2001 standards (spatial resolution, sensitivity, count rate performance, accuracy of count losses, and random coincidence correction and image quality), as well as a detailed comparison with the newer D-ST widely used and whose characteristics are already published.

  17. Performance comparison of two commercial BGO-based PET/CT scanners using NEMA NU 2-2001.

    PubMed

    Bolard, Grégory; Prior, John O; Modolo, Luca; Delaloye, Angelika Bischof; Kosinski, Marek; Wastiel, Claude; Malterre, Jérôme; Bulling, Shelley; Bochud, François; Verdun, Francis R

    2007-07-01

    Combined positron emission tomography and computed tomography (PET/CT) scanners play a major role in medicine for in vivo imaging in an increasing number of diseases in oncology, cardiology, neurology, and psychiatry. With the advent of short-lived radioisotopes other than 18F and newer scanners, there is a need to optimize radioisotope activity and acquisition protocols, as well as to compare scanner performances on an objective basis. The Discovery-LS (D-LS) was among the first clinical PET/CT scanners to be developed and has been extensively characterized with older National Electrical Manufacturer Association (NEMA) NU 2-1994 standards. At the time of publication of the latest version of the standards (NU 2-2001) that have been adapted for whole-body imaging under clinical conditions, more recent models from the same manufacturer, i.e., Discovery-ST (D-ST) and Discovery-STE (D-STE), were commercially available. We report on the full characterization both in the two- and three-dimensional acquisition mode of the D-LS according to latest NEMA NU 2-2001 standards (spatial resolution, sensitivity, count rate performance, accuracy of count losses, and random coincidence correction and image quality), as well as a detailed comparison with the newer D-ST widely used and whose characteristics are already published.

  18. Hierarchical CT to Ultrasound Registration of the Lumbar Spine: A Comparison with Other Registration Methods.

    PubMed

    Koo, Terry K; Kwok, Wingchi Edmund

    2016-10-01

    Three-dimensional (3D) measurement of the spine can provide important information for functional, developmental, diagnostic, and treatment-effect evaluations. However, existing measurement techniques are either 2-dimensional, highly invasive, or involve a high radiation dose, prohibiting their widespread and repeated use in both research and clinical settings. Non-invasive, non-ionizing, 3D measurement of the spine is still beyond the current state-of-the-art. Towards this goal, we developed an intensity-based hierarchical CT-ultrasound registration approach to quantify the 3D positions and orientations of lumbar vertebrae from 3D freehand ultrasound and one-time computed tomography. The method was validated using a human dry bone specimen (T12-L5) and a porcine cadaver (L2-L6) by comparing the registration results with a gold standard fiducial-based registration. Mean (SD) target registration error and percentage of successful registration were 1.2 (0.6) mm and 100% for the human dry bone specimen, and 2.18 (0.82) mm and 92% for the porcine cadaver, indicating that the method is accurate and robust under clinically realistic conditions. Given that the use of ultrasound eliminates ionizing radiation during pose measurements, we believe that the hierarchical CT-ultrasound registration method is an attractive option for quantifying 3D poses of individual vertebra and motion segment, and thus warrants further investigations.

  19. Comparison of dose measurements in CT using a novel semiconductor detector and a small ion chamber

    SciTech Connect

    Paschoal, Cinthia M. M.; Ferreira, Fernanda Carla L.; Santos, Luiz A. P.; Souza, Divanizia N.

    2015-07-01

    The advance of multislice computed tomography (CT) has become inadequate the currently dosimetric protocol used in CT. Instead of dosimetry based on the measurement of CTDI using a pencil ion chamber of 100 m of length, it was proposed the use of a small ion chamber (IC) and the calculating the dose equilibrium (Deq) at the location of the chamber. The objective of this work was to compare the performance of a short IC and a commercial photodiode to measure the accumulated dose at the center of the scan length L, DL(0), and to obtain the equilibrium dose Deq using the two detectors. The result for L=100 mm was compared with the result of a pencil chamber. The results indicate that the commercial photodiode is suitable to measure the accumulated dose at the center of the scan length L as compared with the ion chambers. This methodology allows measurements of the accumulated dose for any desired scan length, allowing measuring the equilibrium dose Deq if the phantom is long enough to allow it. (authors)

  20. Comparison of models and acquisition techniques for estimation of myocardial blood flow from CT

    NASA Astrophysics Data System (ADS)

    Alessio, Adam M.; Branch, Kelley R.; Caldwell, James H.; Bassingthwaighte, James B.

    2011-03-01

    Dynamic contrast enhanced CT has been successfully applied in cardiac imaging for the estimation of myocardial blood flow (MBF). In general, these acquisitions impart a relatively high radiation dose because they require continuous or gated imaging of the heart for 15-40 seconds. At present, there is no consensus on the appropriate estimation method to derive MBF and on the appropriate acquisition technique to minimize dose while maintaining MBF estimation accuracy and precision. This work explores the tradeoff of accuracy and precision of MBF estimates with several estimation methods and acquisition techniques in support of the fundamental goal of optimizing dynamic cardiac CT in terms of radiation dose and MBF estimation fidelity. We simulated time attenuation curves (TACs) for a range of flow states (Flow = [0.8, 1.6, 2.4, 3.2] ml/g/min) and several acquisition techniques. We estimated MBF with 5 different methods for each simulated TAC. From multiple independent realizations, we assessed the accuracy and precision of each method. Results show that acquisition techniques with 1/3 tube current or 1/3 temporal sampling permits accurate MBF estimates with most methods with reduction in MBF estimate precision by on average 30%. Furthermore, reduction in model complexity can be beneficial for improving the precision of MBF estimates.

  1. Comparison of effective radiation doses from X-ray, CT, and PET/CT in pediatric patients with neuroblastoma using a dose monitoring program

    PubMed Central

    Kim, Yeun Yoon; Shin, Hyun Joo; Kim, Myung-Joon; Lee, Mi-Jung

    2016-01-01

    PURPOSE We aimed to evaluate the use of a dose monitoring program for calculating and comparing the diagnostic radiation doses in pediatric patients with neuroblastoma. METHODS We retrospectively reviewed diagnostic and therapeutic imaging studies performed on pediatric patients with neuroblastoma from 2003 to 2014. We calculated the mean effective dose per exam for X-ray, conventional computed tomography (CT), and CT of positron emission tomography/computed tomography (PET/CT) from the data collected using a dose monitoring program (DoseTrack group) since October 2012. Using the data, we estimated the cumulative dose per person and the relative dose from each modality in all patients (Total group). The effective dose from PET was manually calculated for all patients. RESULTS We included 63 patients with a mean age of 3.2±3.5 years; 28 had a history of radiation therapy, with a mean irradiated dose of 31.9±23.2 Gy. The mean effective dose per exam was 0.04±0.19 mSv for X-ray, 1.09±1.11 mSv for CT, and 8.35±7.45 mSv for CT of PET/CT in 31 patients of the Dose-Track group. The mean estimated cumulative dose per patient in the Total group was 3.43±2.86 mSv from X-ray (8.5%), 7.66±6.09 mSv from CT (19.1%), 18.35±13.52 mSv from CT of PET/CT (45.7%), and 10.71±10.05 mSv from PET (26.7%). CONCLUSION CT of PET/CT contributed nearly half of the total cumulative dose in pediatric patients with neuroblastoma. The radiation dose from X-ray was not negligible because of the large number of X-ray images. A dose monitoring program can be useful for calculating radiation doses in patients with cancer. PMID:27306659

  2. X-ray CT analyses, models and numerical simulations: a comparison with petrophysical analyses in an experimental CO2 study

    NASA Astrophysics Data System (ADS)

    Henkel, Steven; Pudlo, Dieter; Enzmann, Frieder; Reitenbach, Viktor; Albrecht, Daniel; Ganzer, Leonhard; Gaupp, Reinhard

    2016-06-01

    An essential part of the collaborative research project H2STORE (hydrogen to store), which is funded by the German government, was a comparison of various analytical methods for characterizing reservoir sandstones from different stratigraphic units. In this context Permian, Triassic and Tertiary reservoir sandstones were analysed. Rock core materials, provided by RWE Gasspeicher GmbH (Dortmund, Germany), GDF Suez E&P Deutschland GmbH (Lingen, Germany), E.ON Gas Storage GmbH (Essen, Germany) and RAG Rohöl-Aufsuchungs Aktiengesellschaft (Vienna, Austria), were processed by different laboratory techniques; thin sections were prepared, rock fragments were crushed and cubes of 1 cm edge length and plugs 3 to 5 cm in length with a diameter of about 2.5 cm were sawn from macroscopic homogeneous cores. With this prepared sample material, polarized light microscopy and scanning electron microscopy, coupled with image analyses, specific surface area measurements (after Brunauer, Emmet and Teller, 1938; BET), He-porosity and N2-permeability measurements and high-resolution microcomputer tomography (μ-CT), which were used for numerical simulations, were applied. All these methods were practised on most of the same sample material, before and on selected Permian sandstones also after static CO2 experiments under reservoir conditions. A major concern in comparing the results of these methods is an appraisal of the reliability of the given porosity, permeability and mineral-specific reactive (inner) surface area data. The CO2 experiments modified the petrophysical as well as the mineralogical/geochemical rock properties. These changes are detectable by all applied analytical methods. Nevertheless, a major outcome of the high-resolution μ-CT analyses and following numerical data simulations was that quite similar data sets and data interpretations were maintained by the different petrophysical standard methods. Moreover, the μ-CT analyses are not only time saving, but also

  3. Comparisons of obesity assessments in over-weight elementary students using anthropometry, BIA, CT and DEXA.

    PubMed

    Yu, Ok-Kyeong; Rhee, Yang-Keun; Park, Tae-Sun; Cha, Youn-Soo

    2010-04-01

    Obesity was characterized in Korean elementary students using different obesity assessment tests on 103 overweight elementary students from three schools of Jeonbuk Province. The body mass index (BMI) and obesity index (OI) were compared, and the data using DEXA and CT were compared with the data using BIA and a tape measure. The results of this study are as follows: first, 27 students who were classified as obese by OI were classified as overweight by BMI, and 3 students who were classified as standard weight by BMI were classified as overweight by OI. Secondly, by DEXA and BIA measurements, there was 1.51% difference in body fat percentage (boys 1.66%, girls 1.17%) and the difference in body fat mass between boys and girls was 0.77 kg (boys 0.85 kg, girls 0.59 kg), but those differences in body fat percentage and mass were not statistically significant. Thirdly, the average total abdominal fat (TAF) measured by CT scans of obese children was more significantly related with subcutaneous fat (r = 0.983, P < 0.01) than visceral fat (r = 0.640, P < 0.01). Also, TAF were highest significant with waist circumference by a tape measure (r = 0.744, P < 0.01). In summary, as there are some differences of assessment results between two obesity test methods (BMI, OI), we need more definite standards to determine the degree of obesity. The BIA seems to be the most simple and effective way to measure body fat mass, whereas waist/hip ratio (WHR) using a tape measurer is considered to be the most effective method for assessing abdominal fat in elementary students.

  4. Comparison of manual vs. automated multimodality (CT-MRI) image registration for brain tumors

    SciTech Connect

    Sarkar, Abhirup; Santiago, Roberto J.; Smith, Ryan; Kassaee, Alireza . E-mail: Kassaee@xrt.upenn.edu

    2005-03-31

    Computed tomgoraphy-magnetic resonance imaging (CT-MRI) registrations are routinely used for target-volume delineation of brain tumors. We clinically use 2 software packages based on manual operation and 1 automated package with 2 different algorithms: chamfer matching using bony structures, and mutual information using intensity patterns. In all registration algorithms, a minimum of 3 pairs of identical anatomical and preferably noncoplanar landmarks is used on each of the 2 image sets. In manual registration, the program registers these points and links the image sets using a 3-dimensional (3D) transformation. In automated registration, the 3 landmarks are used as an initial starting point and further processing is done to complete the registration. Using our registration packages, registration of CT and MRI was performed on 10 patients. We scored the results of each registration set based on the amount of time spent, the accuracy reported by the software, and a final evaluation. We evaluated each software program by measuring the residual error between 'matched' points on the right and left globes and the posterior fossa for fused image slices. In general, manual registration showed higher misalignment between corresponding points compared to automated registration using intensity matching. This error had no directional dependence and was, most of the time, larger for a larger structure in both registration techniques. Automated algorithm based on intensity matching also gave the best results in terms of registration accuracy, irrespective of whether or not the initial landmarks were chosen carefully, when compared to that done using bone matching algorithm. Intensity-matching algorithm required the least amount of user-time and provided better accuracy.

  5. Comparison of CT duodeno-cholangiopancreatography to ERCP for assessing biliary obstruction.

    PubMed

    Kielar, Ania; Toa, Hardy; Sekar, Arni; Mimeault, Richard; Jaffey, James

    2005-01-01

    The authors have developed a CT protocol, CT duodeno-cholangiopancreatography (CDCP), which is performed during a single contrast-enhanced phase, proceeding cranially, allowing enhancement of the pancreas during its parenchymal phase followed by enhancement of the liver during its portal-venous phase. This retrospective pilot study evaluates CDCP compared with endoscopic retrograde cholangiopancreatography (ERCP) as a diagnostic tool for assessing the cause and level of biliary obstruction. Forty-one patients with jaundice underwent CDCP and ERCP between October 2002 and May 2004. Pathologic confirmation was obtained in 31 of the 41 (76%) patients. The sensitivity, specificity, and kappa values of CDCP and ERCP compared with pathology were calculated for tumors and stones. Pathology-proven cases included 7 cases of stones, 23 tumors, and 1 other cause of obstruction. The overall level of agreement of diagnoses between CDCP and pathology was 29 of 31 (93.5%); that between CDCP and ERCP was 36 of 41 (88%). Comparing CDCP to pathology for tumors, the sensitivity was 100%, the specificity was 89%, and the kappa was 0.92 (95% CI 0.76-1.0). For stone detection, CDCP had a sensitivity of 86%, a specificity of 100%, and a kappa value of 0.90 (95% CI 0.72-1.0). For level of obstruction of the common bile duct, comparing CDCP to ERCP, observations agreed in 31 of the 36 (86%) cases; for the pancreatic duct, observations agreed in 24 of the 25 (96%) cases. CDCP is a noninvasive diagnostic tool that can be used to assess the cause and level of obstruction. A blinded prospective study would be valuable to further assess the merits of CDCP.

  6. Diagnostic Performance of Dual-Energy CT Stress Myocardial Perfusion Imaging: Direct Comparison With Cardiovascular MRI

    PubMed Central

    Ko, Sung Min; Song, Meong Gun; Chee, Hyun Kun; Hwang, Hweung Kon; Feuchtner, Gudrun Maria; Min, James K.

    2014-01-01

    OBJECTIVE The purpose of this study was to assess the diagnostic performance of stress perfusion dual-energy CT (DECT) and its incremental value when used with coronary CT angiography (CTA) for identifying hemodynamically significant coronary artery disease. SUBJECTS AND METHODS One hundred patients with suspected or known coronary artery disease without chronic myocardial infarction detected with coronary CTA underwent stress perfusion DECT, stress cardiovascular perfusion MRI, and invasive coronary angiography (ICA). Stress perfusion DECT and cardiovascular stress perfusion MR images were used for detecting perfusion defects. Coronary CTA and ICA were evaluated in the detection of ≥ 50% coronary stenosis. The diagnostic performance of coronary CTA for detecting hemodynamically significant stenosis was assessed before and after stress perfusion DECT on a pervessel basis with ICA and cardiovascular stress perfusion MRI as the reference standard. RESULTS The performance of stress perfusion DECT compared with cardiovascular stress perfusion MRI on a per-vessel basis in the detection of perfusion defects was sensitivity, 89%; specificity, 74%; positive predictive value, 73%; negative predictive value, 90%. Per segment, these values were sensitivity, 76%; specificity, 80%; positive predictive value, 63%; and negative predictive value, 88%. Compared with ICA and cardiovascular stress perfusion MRI per vessel territory the sensitivity, specificity, positive predictive value, and negative predictive value of coronary CTA were 95%, 61%, 61%, and 95%. The values for stress perfusion DECT were 92%, 72%, 68%, and 94%. The values for coronary CTA and stress perfusion DECT were 88%, 79%, 73%, and 91%. The ROC AUC increased from 0.78 to 0.84 (p = 0.02) with the use of coronary CTA and stress perfusion DECT compared with coronary CTA alone. CONCLUSION Stress perfusion DECT plays a complementary role in enhancing the accuracy of coronary CTA for identifying hemodynamically

  7. Comparison of CT and MR in 400 patients with suspected disease of the brain and cervical spinal cord

    SciTech Connect

    Bradley, W.G. Jr.; Waluch, V.; Yadley, R.A.; Wycoff, R.R.

    1984-09-01

    Magnetic resonance imaging (MR) (0.35T) and computed tomography (CT) were compared in 400 consecutive patients with suspected disease of the brain and cervical spinal cord. Of 325 positive diagnoses, MR detected abnormality while CT was normal in 93; MR was more specific in 68; MR and CT gave equivalent information in 129; CT was more specific in 32; and CT was positive while MR was normal in 3. MR was superior to CT in detection of multiple sclerosis, subcortical arteriosclerotic encephalopathy, posterior fossa infarcts and tumors, small extra-axial fluid collections, and cervical syringomyelia. CT was preferable in evaluation of meningiomas and separation of tumor from edema. CT takes less time and may be preferable in patients with acute trauma as well as very young or elderly individuals. Thus the two studies should be considered complementary.

  8. Comparison of 68Ga-DOTANOC PET/CT and contrast-enhanced CT in localisation of tumours in ectopic ACTH syndrome

    PubMed Central

    Jadhav, Swati S; Lila, Anurag R; Kasaliwal, Rajeev; Khare, Shruti; Yerawar, Chaitanya G; Hira, Priya; Phadke, Uday; Shah, Hina; Lele, Vikram R; Malhotra, Gaurav; Bandgar, Tushar; Shah, Nalini S

    2016-01-01

    Background Localising ectopic adrenocorticotrophic hormone (ACTH) syndrome (EAS) tumour source is challenging. Somatostatin receptor-based PET imaging has shown promising results, but the data is limited to case reports and small case series. We reviewed here the performance of 68Ga-DOTANOC positron emission tomography (PET)/computed tomography (CT) and contrast-enhanced CT (CECT) in our cohort of 12 consecutive EAS patients. Materials and methods Retrospective data analysis of 12 consecutive patients of EAS presenting to a single tertiary care centre in a period between January 2013 and December 2014 was done. CECT and 68Ga-DOTANOC PET/CT were reported (blinded) by an experienced radiologist and a nuclear medicine physician, respectively. The performance of CECT and 68Ga-DOTANOC PET/CT was compared. Results Tumours could be localised in 11 out of 12 patients at initial presentation (overt cases), whereas in one patient, tumour remained occult. Thirteen lesions were identified in 11 patients as EAS source (true positives). CECT localised 12 out of these 13 lesions (sensitivity 92.3%) and identified five false-positive lesions (positive predictive value (PPV) 70.5%). Compared with false-positive lesions, true-positive lesions had greater mean contrast enhancement at 60s (33.2 vs 5.6 Hounsfield units (HU)). 68Ga-DOTANOC PET/CT was able to identify 9 out of 13 lesions (sensitivity 69.2%) and reported no false-positive lesions (PPV 100%). Conclusion CECT remains the first-line investigation in localisation of EAS. The contrast enhancement pattern on CECT can further aid in characterisation of the lesions. 68Ga-DOTANOC PET/CT can be added to CECT, to enhance positive prediction of the suggestive lesions. PMID:27006371

  9. Comparison of FDG-PET/CT images between chronic renal failure patients on hemodialysis and controls.

    PubMed

    Toriihara, Akira; Kitazume, Yoshio; Nishida, Hidenori; Kubota, Kazunori; Nakadate, Masashi; Tateishi, Ukihide

    2015-01-01

    The whole-body 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) distribution in chronic renal failure (CRF) patients on hemodialysis would be different from that in subjects with normal renal function, because they lack urinary FDG excretion and remain in a constant volume overload. We evaluated the difference in the physiological uptake pattern of FDG between chronic renal failure patients on hemodialysis and control subjects. The subjects for this retrospective study consisted of 24 chronic renal failure patients on hemodialysis (HD group) and 24 age- and sex-matched control subjects (NC group). Standardized uptake values normalized by the body weight (SUVbw), ideal body weight (SUVibw), lean body mass (SUVlbm), and body surface area (SUVbsa) in the cerebellum, lungs, liver, gluteal muscles and subcutaneous fat, spleen, thoracolumbar spine, thoracic and abdominal aorta, and right atrium were calculated in positron emission tomography/computed tomography (PET/CT) images. SUVbw in the gluteal muscles, subcutaneous fat, spleen and right atrium was significantly higher in the HD group as compared to that in the NC group (p < 0.05; unpaired t test). In addition, SUVibm, SUVlbm, as well as SUVbsa in the abdominal aorta were significantly higher in the HD group as compared to those in the NC group (p < 0.05; unpaired t test). In conclusion, as compared to normal subjects, chronic renal failure patients on hemodialysis show significantly higher physiological FDG uptake in the soft tissues, spleen and blood pool.

  10. [Evaluation of an adaptive filter for CT under low-CNR condition: comparison with linear filter].

    PubMed

    Mori, Issei; Uchida, Miho; Sato, Ami; Sato, Shingo; Tamura, Hajime; Takai, Yoshihiro; Ishibashi, Tadashi; Saito, Haruo; Hosokai, Yoshiyuki; Ogura, Takahide; Chida, Koichi; Machida, Yoshio

    2009-01-20

    The use of an adaptive filter for CT images is becoming a common procedure and is said to reduce image noise while preserving sharpness and helping to reduce the required X-ray dose. Although many reports support this view, the validity of such evaluations is arguable. When the linearity of a system is in question, physical performance indexes should be measured under conditions similar to those of clinical use. Evaluations of diagnosis using clinical images may be fallible because the non-filtered image used as the reference might not have been optimally reconstructed. We have chosen simple, but commonly used, adaptive filters for our evaluation. As a reference for comparing performance, we designed linear filters that best approximate the noise characteristics of the adaptive filters. MTF is measured through observation of the edge-spread function. Clinical abdominal images are used to compare the performance of adaptive filters and linear filters. We conclude that the performance of the type of adaptive filter we have chosen is virtually the same as that of the linear filter, as long as the image quality of soft tissues is our interest. Both the noise SD and MTF are virtually the same if the contrast of the object is not substantially higher than 150 HU. Images of soft tissues obtained with the use of adaptive filters are also virtually the same as those obtained by linear filters. The edge-preservation characteristic of this adaptive filter is not observable for soft tissues.

  11. Forming Simulation of Thick AFP Laminates and Comparison with Live CT Imaging

    NASA Astrophysics Data System (ADS)

    Leutz, Daniel; Vermilyea, Mark; Bel, Sylvain; Hinterhölzl, Roland

    2016-08-01

    Automated fiber placement (AFP) process can be used to manufacture laminates by laying up unidirectional slit tapes along a desired path and placing multiple layers on top of each other. Usually, the slit tapes are placed direct onto the tooling to attain the final part geometry. Alternatively, the laminate can be built up on a planar substrate and can be subsequently formed into the final shape. This kind of processing allows manufacturing highly curved parts, which may not be possible with the direct placement. In the present work a forming simulation of thick AFP laminates is developed to predict the tapes' orientations and delamination as well as transverse tape spread-ups and separations during the forming process. The simulation model is built up through the material characterization experiments. Validation is performed comparing the results of the simulation vs. the experimental forming on two generic geometries. An optical inspection is made on the external layers of the laminates. In a second step, live computer tomography (CT) scans are used to inspect the tapes within an AFP laminate during forming of an L- and a Z-flange. Tapes re-orientation, gaps and tapes widening are observed experimentally and compared to the simulation results. The simulation is capable to predict the tows orientation and provides indicators concerning the tows spread-up and separation.

  12. Comparisons of Derived Metrics from Computed Tomography (CT) Scanned Images of Fluvial Sediment from Gravel-Bed Flume Experiments

    NASA Astrophysics Data System (ADS)

    Voepel, Hal; Ahmed, Sharif; Hodge, Rebecca; Leyland, Julian; Sear, David

    2016-04-01

    Uncertainty in bedload estimates for gravel bed rivers is largely driven by our inability to characterize arrangement, orientation and resultant forces of fluvial sediment in river beds. Water working of grains leads to structural differences between areas of the bed through particle sorting, packing, imbrication, mortaring and degree of bed armoring. In this study, non-destructive, micro-focus X-ray computed tomography (CT) imaging in 3D is used to visualize, quantify and assess the internal geometry of sections of a flume bed that have been extracted keeping their fabric intact. Flume experiments were conducted at 1:1 scaling of our prototype river. From the volume, center of mass, points of contact, and protrusion of individual grains derived from 3D scan data we estimate 3D static force properties at the grain-scale such as pivoting angles, buoyancy and gravity forces, and local grain exposure. Here metrics are derived for images from two flume experiments: one with a bed of coarse grains (>4mm) and the other where sand and clay were incorporated into the coarse flume bed. In addition to deriving force networks, comparison of metrics such as critical shear stress, pivot angles, grain distributions, principle axis orientation, and pore space over depth are made. This is the first time bed stability has been studied in 3D using CT scanned images of sediment from the bed surface to depths well into the subsurface. The derived metrics, inter-granular relationships and characterization of bed structures will lead to improved bedload estimates with reduced uncertainty, as well as improved understanding of relationships between sediment structure, grain size distribution and channel topography.

  13. Comparison of human and Hotelling observer performance for a fan-beam CT signal detection task

    PubMed Central

    Sanchez, Adrian A.; Sidky, Emil Y.; Reiser, Ingrid; Pan, Xiaochuan

    2013-01-01

    Purpose: A human observer study was performed for a signal detection task for the case of fan-beam x-ray computed tomography. Hotelling observer (HO) performance was calculated for the same detection task without the use of efficient channels. By considering the full image covariance produced by the filtered backprojection (FBP) algorithm and avoiding the use of channels in the computation of HO performance, the authors establish an absolute upper bound on signal detectability. Therefore, this study serves as a baseline for relating human and ideal observer performance in the case of fan-beam CT. Methods: Eight human observers participated in a two-alternative forced choice experiment where the signal of interest was a small simulated ellipsoid in the presence of independent, identically distributed Gaussian detector noise. Theoretical performance of the HO, which is equivalent to the ideal observer in this case (see Sec. 13.2.12 in Barrett and Myers [Foundations of Image Science (Wiley, Hoboken, NJ, 2004)], was also computed and compared to the performance of the human observers. In addition to a reference FBP implementation, two FBP implementations with inherent loss of HO signal detectability (e.g., by apodizing the ramp filter) were also investigated. Each of these latter two implementations takes the form of a discrete-to-discrete linear operator (i.e., a matrix), which has a nontrivial null-space resulting in the loss of detectability. Results: Estimated observer detectability index (\\documentclass[12pt]{minimal}\\begin{document}$\\hat{d}_A$\\end{document}d^A) values for the human observers and SNR values for the HO were obtained. While Hanning filtering in the FBP implementation with a cutoff frequency of 1/4 of the Nyquist frequency reduces HO SNR (due to the reconstruction matrix's nontrivial null-space), this filtering was shown to consistently improve human observer performance. By contrast, increasing the image pixel size was seen to have a comparable

  14. Comparison of tibiofemoral joint space width measurements from standing CT and fixed flexion radiography.

    PubMed

    Segal, Neil A; Frick, Eric; Duryea, Jeffrey; Nevitt, Michael C; Niu, Jingbo; Torner, James C; Felson, David T; Anderson, Donald D

    2016-08-09

    The objective of this project was to determine the relationship between medial tibiofemoral joint space width measured on fixed-flexion radiographs and the three-dimensional joint space width distribution on low-dose, standing CT (SCT) imaging. At the 84-month visit of the Multicenter Osteoarthritis Study, 20 participants were recruited. A commercial SCT scanner for the foot and ankle was modified to image knees while standing. Medial tibiofemoral joint space width was assessed on radiographs at fixed locations from 15-30% of compartment width using validated software and on SCT by mapping the distances between three-dimensional subchondral bone surfaces. Individual joint space width values from radiographs were compared with three-dimensional joint space width values from corresponding sagittal plane locations using paired t-tests and correlation coefficients. For the 4 medial-most tibiofemoral locations, radiographic joint space width values exceeded the minimal joint space width on SCT by a mean of 2.0mm and were approximately equal to the 61st percentile value of the joint space width distribution at each respective sagittal-plane location. Correlation coefficients at these locations were 0.91-0.97 and the offsets between joint space width values from radiographs and SCT measurements were consistent. There were greater offsets and variability in the offsets between modalities closer to the tibial spine. Joint space width measurements on fixed-flexion radiographs are highly correlated with three-dimensional joint space width from SCT. In addition to avoiding bony overlap obscuring the joint, a limitation of radiographs, the current study supports a role for SCT in the evaluation of tibiofemoral OA. This article is protected by copyright. All rights reserved.

  15. Comparison measurements of DQE for two flat panel detectors: fluoroscopic detector vs. cone beam CT detector

    NASA Astrophysics Data System (ADS)

    Betancourt Benítez, Ricardo; Ning, Ruola; Conover, David

    2006-03-01

    The physical performance of two flat panel detectors (FPD) has been evaluated using a standard x-ray beam quality set by IEC, namely RQA5. The FPDs evaluated in this study are based on an amorphous silicon photodiode array that is coupled to a thallium-doped Cesium Iodide scintillator and to a thin film transistor (TFT) array. One detector is the PaxScan 2520 that is designed for fluoro imaging, and has a small dynamic range and a large image lag. The other detector is the PaxScan 4030CB that is designed for cone beam CT, and has a large dynamic range (>16-bit), a reduced image lag and many imaging modes. Varian Medical Systems manufactured both detectors. The linearity of the FPDs was investigated by using an ionization chamber and aluminum filtration in order to obtain the beam quality. Since the FPDs are used in fluoroscopic mode, image lag of the FPD was measured in order to investigate its effect on this study, especially its effect on DQE. The spatial resolution of the FPDs was determined by obtaining the pre-sampling modulation transfer function for each detector. A sharp edge was used in accordance to IEC 62220-1. Next, the Normalized Noise Power Spectrum (NNPS) was calculated for various exposures levels at RQA5 radiation quality. Finally, the DQE of each FPD was obtained with a modified version of the international standard set by IEC 62220-1. The results show that the physical performance in DQE and MTF of the PaxScan 4030CB is superior to that of PaxScan2520.

  16. Efficacy and safety of CT-P13 (biosimilar infliximab) in patients with rheumatoid arthritis: comparison between switching from reference infliximab to CT-P13 and continuing CT-P13 in the PLANETRA extension study

    PubMed Central

    Yoo, Dae Hyun; Prodanovic, Nenad; Jaworski, Janusz; Miranda, Pedro; Ramiterre, Edgar; Lanzon, Allan; Baranauskaite, Asta; Wiland, Piotr; Abud-Mendoza, Carlos; Oparanov, Boycho; Smiyan, Svitlana; Kim, HoUng; Lee, Sang Joon; Kim, SuYeon; Park, Won

    2017-01-01

    Objectives To assess the efficacy and safety of switching from the infliximab reference product (RP; Remicade) to its biosimilar CT-P13 (Remsima, Inflectra) or continuing CT-P13 in patients with rheumatoid arthritis (RA) for an additional six infusions. Methods This open-label extension study recruited patients with RA who had completed the 54-week, randomised, parallel-group study comparing CT-P13 with RP (PLANETRA; NCT01217086). CT-P13 (3 mg/kg) was administered intravenously every 8 weeks from weeks 62 to 102. All patients received concomitant methotrexate. Endpoints included American College of Rheumatology 20% (ACR20) response, ACR50, ACR70, immunogenicity and safety. Data were analysed for patients who received CT-P13 for 102 weeks (maintenance group) and for those who received RP for 54 weeks and then switched to CT-P13 (switch group). Results Overall, 302 of 455 patients who completed the PLANETRA study enrolled into the extension. Of these, 158 had received CT-P13 (maintenance group) and 144 RP (switch group). Response rates at week 102 for maintenance versus switch groups, respectively, were 71.7% vs 71.8% for ACR20, 48.0% vs 51.4% for ACR50 and 24.3% vs 26.1% for ACR70. The proportion of patients with antidrug antibodies was comparable between groups (week 102: 40.3% vs 44.8%, respectively). Treatment-emergent adverse events occurred in similar proportions of patients in the two groups during the extension study (53.5% and 53.8%, respectively). Conclusions Comparable efficacy and tolerability were observed in patients who switched from RP to its biosimilar CT-P13 for an additional year and in those who had long-term CT-P13 treatment for 2 years. Trial registration number NCT01571219; Results. PMID:27130908

  17. Regadenoson-stress myocardial CT perfusion and single-photon emission CT: rationale, design, and acquisition methods of a prospective, multicenter, multivendor comparison.

    PubMed

    Cury, Ricardo C; Kitt, Therese M; Feaheny, Kathleen; Akin, Jamie; George, Richard T

    2014-01-01

    Pharmacologic stress myocardial CT perfusion (CTP) has been reported to be a viable imaging modality for detection of myocardial ischemia compared with single-photon emission CT (SPECT) in several single-center studies. However, regadenoson-stress CTP has not previously been compared with SPECT in a multicenter, multivendor study. The rationale and design of a phase 2, randomized, cross-over study of regadenoson-stress myocardial perfusion imaging by CTP compared with SPECT are described herein. The study will be conducted at approximately 25 sites by using 6 different CT scanner models, including 64-, 128-, 256-, and 320-slice systems. Subjects with known/suspected coronary artery disease will be randomly assigned to 1 of 2 imaging procedure sequences; rest and regadenoson-stress SPECT on day 1, then regadenoson-stress CTP and rest CTP/coronary CT angiography (same acquisition) on day 2; or regadenoson-stress CTP and rest CTP/CT angiography on day 1, then rest and regadenoson-stress SPECT on day 2. The prespecified primary analysis examines the agreement rate between CTP and SPECT for detecting or excluding ischemia (≥2 or 0-1 reversible defects, respectively), as assessed by 3 independent blinded readers for each modality. Non-inferiority will be indicated if the lower boundary of the 95% CI for the agreement rate is within 0.15 of 0.78 (the observed agreement rate in the regadenoson pivotal trials). The protocol described herein will support the first evaluation of regadenoson-stress CTP by using multiple scanner types compared with SPECT.

  18. Dose measurements for dental cone-beam CT: a comparison with MSCT and panoramic imaging

    NASA Astrophysics Data System (ADS)

    Deman, P.; Atwal, P.; Duzenli, C.; Thakur, Y.; Ford, N. L.

    2014-06-01

    To date there is a lack of published information on appropriate methods to determine patient doses from dental cone-beam computed tomography (CBCT) equipment. The goal of this study is to apply and extend the methods recommended in the American Association of Physicists in Medicine (AAPM) Report 111 for CBCT equipment to characterize dose and effective dose for a range of dental imaging equipment. A protocol derived from the one proposed by Dixon et al (2010 Technical Report 111, American Association of Physicist in Medicine, MD, USA), was applied to dose measurements of multi-slice CT, dental CBCT (small and large fields of view (FOV)) and a dental panoramic system. The computed tomography dose index protocol was also performed on the MSCT to compare both methods. The dose distributions in a cylindrical polymethyl methacrylate phantom were characterized using a thimble ionization chamber and Gafchromic™ film (beam profiles). Gafchromic™ films were used to measure the dose distribution in an anthropomorphic phantom. A method was proposed to extend dose estimates to planes superior and inferior to the central plane. The dose normalized to 100 mAs measured in the center of the phantom for the large FOV dental CBCT (11.4 mGy/100 mAs) is two times lower than that of MSCT (20.7 mGy/100 mAs) for the same FOV, but approximately 15 times higher than for a panoramic system (0.6 mGy/100 mAs). The effective dose per scan (in clinical conditions) found for the dental CBCT are 167.60 ± 3.62, 61.30 ± 3.88 and 92.86 ± 7.76 mSv for the Kodak 9000 (fixed scan length of 3.7 cm), and the iCAT Next Generation for 6 cm and 13 cm scan lengths respectively. The method to extend the dose estimates from the central slice to superior and inferior slices indicates a good agreement between theory and measurement. The Gafchromic™ films provided useful beam profile data and 2D distributions of dose in phantom.

  19. Comparison of CNG and LNG technologies for transportation applications

    SciTech Connect

    Sinor, J.E. Consultants, Inc., Niwot, CO )

    1992-01-01

    This report provides a head-to-head comparison of compressed natural gas (CNG) and liquefied natural gas (LNG) supplied to heavy-duty vehicles. The comparison includes an assessment of the overall efficiency of the fuel delivery system, the cost of the fuel supply system, the efficiency of use in heavy-duty vehicles, and the environmental impact of each technology. The report concludes that there are applications in which CNG will have the advantage, and applications in which LNG will be preferred.

  20. Comparison between manual and semi-automatic segmentation of nasal cavity and paranasal sinuses from CT images.

    PubMed

    Tingelhoff, K; Moral, A I; Kunkel, M E; Rilk, M; Wagner, I; Eichhorn, K G; Wahl, F M; Bootz, F

    2007-01-01

    Segmentation of medical image data is getting more and more important over the last years. The results are used for diagnosis, surgical planning or workspace definition of robot-assisted systems. The purpose of this paper is to find out whether manual or semi-automatic segmentation is adequate for ENT surgical workflow or whether fully automatic segmentation of paranasal sinuses and nasal cavity is needed. We present a comparison of manual and semi-automatic segmentation of paranasal sinuses and the nasal cavity. Manual segmentation is performed by custom software whereas semi-automatic segmentation is realized by a commercial product (Amira). For this study we used a CT dataset of the paranasal sinuses which consists of 98 transversal slices, each 1.0 mm thick, with a resolution of 512 x 512 pixels. For the analysis of both segmentation procedures we used volume, extension (width, length and height), segmentation time and 3D-reconstruction. The segmentation time was reduced from 960 minutes with manual to 215 minutes with semi-automatic segmentation. We found highest variances segmenting nasal cavity. For the paranasal sinuses manual and semi-automatic volume differences are not significant. Dependent on the segmentation accuracy both approaches deliver useful results and could be used for e.g. robot-assisted systems. Nevertheless both procedures are not useful for everyday surgical workflow, because they take too much time. Fully automatic and reproducible segmentation algorithms are needed for segmentation of paranasal sinuses and nasal cavity.

  1. Tracer kinetic analysis of dynamic contrast-enhanced MRI and CT bladder cancer data: A preliminary comparison to assess the magnitude of water exchange effects.

    PubMed

    Bains, Lauren J; McGrath, Deirdre M; Naish, Josephine H; Cheung, Susan; Watson, Yvonne; Taylor, M Ben; Logue, John P; Parker, Geoffrey J M; Waterton, John C; Buckley, David L

    2010-08-01

    The purpose of this study was to determine the impact of water exchange on tracer kinetic parameter estimates derived from T(1)-weighted dynamic contrast-enhanced (DCE)-MRI data using a direct quantitative comparison with DCE-CT. Data were acquired from 12 patients with bladder cancer who underwent DCE-CT followed by DCE-MRI within a week. A two-compartment tracer kinetic model was fitted to the CT data, and two versions of the same model with modifications to account for the fast exchange and no exchange limits of water exchange were fitted to the MR data. The two-compartment tracer kinetic model provided estimates of the fractional plasma volume (v(p)), the extravascular extracellular space fraction (v(e)), plasma perfusion (F(p)), and the microvascular permeability surface area product. Our findings suggest that DCE-CT is an appropriate reference for DCE-MRI in bladder cancers as the only significant difference found between CT and MR parameter estimates were the no exchange limit estimates of v(p) (P = 0.002). These results suggest that although water exchange between the intracellular and extravascular-extracellular space has a negligible effect on DCE-MRI, vascular-extravascular-extracellular space water exchange may be more important.

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

    SciTech Connect

    La Fontaine, M; Bradshaw, T; Kubicek, L; Forrest, L; Jeraj, R

    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}) 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

  3. Comparison of pre/post-operative CT image volumes to preoperative digitization of partial hepatectomies: a feasibility study in surgical validation

    NASA Astrophysics Data System (ADS)

    Dumpuri, Prashanth; Clements, Logan W.; Li, Rui; Waite, Jonathan M.; Stefansic, James D.; Geller, David A.; Miga, Michael I.; Dawant, Benoit M.

    2009-02-01

    Preoperative planning combined with image-guidance has shown promise towards increasing the accuracy of liver resection procedures. The purpose of this study was to validate one such preoperative planning tool for four patients undergoing hepatic resection. Preoperative computed tomography (CT) images acquired before surgery were used to identify tumor margins and to plan the surgical approach for resection of these tumors. Surgery was then performed with intraoperative digitization data acquire by an FDA approved image-guided liver surgery system (Pathfinder Therapeutics, Inc., Nashville, TN). Within 5-7 days after surgery, post-operative CT image volumes were acquired. Registration of data within a common coordinate reference was achieved and preoperative plans were compared to the postoperative volumes. Semi-quantitative comparisons are presented in this work and preliminary results indicate that significant liver regeneration/hypertrophy in the postoperative CT images may be present post-operatively. This could challenge pre/post operative CT volume change comparisons as a means to evaluate the accuracy of preoperative surgical plans.

  4. CT Enterography

    MedlinePlus

    ... obstructions and Crohn’s disease. CT scanning is fast, painless, noninvasive and accurate. CT enterography is better able ... the benefits vs. risks? Benefits CT scanning is painless, noninvasive and accurate. A major advantage of CT ...

  5. MO-E-17A-03: Monte Carlo CT Dose Calculation: A Comparison Between Experiment and Simulation Using ARCHER-CT

    SciTech Connect

    Liu, T; Du, X; Su, L; Gao, Y; Ji, W; Xu, X; Zhang, D; Shi, J; Liu, B; Kalra, M

    2014-06-15

    Purpose: To compare the CT doses derived from the experiments and GPU-based Monte Carlo (MC) simulations, using a human cadaver and ATOM phantom. Methods: The cadaver of an 88-year old male and the ATOM phantom were scanned by a GE LightSpeed Pro 16 MDCT. For the cadaver study, the Thimble chambers (Model 10×5−0.6CT and 10×6−0.6CT) were used to measure the absorbed dose in different deep and superficial organs. Whole-body scans were first performed to construct a complete image database for MC simulations. Abdomen/pelvis helical scans were then conducted using 120/100 kVps, 300 mAs and a pitch factor of 1.375:1. For the ATOM phantom study, the OSL dosimeters were used and helical scans were performed using 120 kVp and x, y, z tube current modulation (TCM). For the MC simulations, sufficient particles were run in both cases such that the statistical errors of the results by ARCHER-CT were limited to 1%. Results: For the human cadaver scan, the doses to the stomach, liver, colon, left kidney, pancreas and urinary bladder were compared. The difference between experiments and simulations was within 19% for the 120 kVp and 25% for the 100 kVp. For the ATOM phantom scan, the doses to the lung, thyroid, esophagus, heart, stomach, liver, spleen, kidneys and thymus were compared. The difference was 39.2% for the esophagus, and within 16% for all other organs. Conclusion: In this study the experimental and simulated CT doses were compared. Their difference is primarily attributed to the systematic errors of the MC simulations, including the accuracy of the bowtie filter modeling, and the algorithm to generate voxelized phantom from DICOM images. The experimental error is considered small and may arise from the dosimeters. R01 grant (R01EB015478) from National Institute of Biomedical Imaging and Bioengineering.

  6. Superior CT coronary angiography image quality at lower radiation exposure with second generation 320-detector row CT in patients with elevated heart rate: a comparison with first generation 320-detector row CT

    PubMed Central

    Soh, Siang Y.; Ko, Brian S. H.; Cameron, James D.; Crossett, Marcus; Nasis, Arthur; Troupis, John; Meredith, Ian T.; Seneviratne, Sujith K.

    2014-01-01

    Background This study aims to compare the image quality of second generation versus first generation 320-computed tomography coronary angiography (CTCA) in patients with heart rate ≥65 bpm as it has not been specifically reported. Methods Consecutive patients who underwent CTCA using second-generation-320-detector-row-CT were prospectively enrolled. A total of 50 patients with elevated (≥65 bpm) heart rate and 50 patients with controlled (<65 bpm) heart rate were included. Age and gender matched patients who were scanned with the first-generation-320-detector-row-CT were retrospectively identified. Image quality in each coronary artery segment was assessed by two blinded CT angiographers using the five-point Likert scale. Results In the elevated heart rate cohorts, while there was no significant difference in heart rate during scan-acquisition (66 vs. 69 bpm, P=0.308), or body mass index (28.5 vs. 29.6, P=0.464), the second generation scanner was associated with better image quality (3.94±0.6 vs. 3.45±0.8, P=0.001), and with lower radiation (2.8 vs. 4.3 mSv, P=0.009). There was no difference in scan image quality for the controlled heart rate cohorts. Conclusions The second generation CT scanner provides better image quality at lower radiation dose in patients with elevated heart rate (≥65 bpm) compared to first generation CT scanner. PMID:25276615

  7. Comparison of CT on Rails With Electronic Portal Imaging for Positioning of Prostate Cancer Patients With Implanted Fiducial Markers

    SciTech Connect

    Owen, Rebecca Kron, Tomas; Foroudi, Farshad; Milner, Alvin; Cox, Jennifer; Duchesne, Gillian; Cleeve, Laurence; Zhu Li; Cramb, Jim; Sparks, Laura; Laferlita, Marcus

    2009-07-01

    Purpose: The objective of this investigation was to measure the agreement between in-room computed tomography (CT) on rails and electronic portal image (EPI) radiography. Methods and Materials: Agreement between the location of the center of gravity (COG) of fiducial markers (FMs) on CT and EPI images was determined in phantom studies and a patient cohort. A secondary analysis between the center of volume (COV) of the prostate on CT and the COG of FMs on CT and EPI was performed. Agreement was defined as the 95% probability of a difference of {<=}3.0 mm between images. Systematic and random errors from CT and EPI are reported. Results: From 8 patients, 254 CT and EPI pairs were analyzed. FMs were localized to within 3 mm on CT and EPI images 96.9% of the time in the left-right (LR) plane, 85.8% superior-inferior (SI), and 89% anterior-posterior (AP). The differences between the COV on CT and the COG on EPI were not within 3 mm in any plane: 87.8% (LR), 64.2% (SI), and 70.9% (AP). The systematic error varied from 1.2 to 2.9 mm (SI) and 1.8-2.9 mm (AP) between the COG on EPI and COV on CT. Conclusions: Considerable differences between in-room CT and EPI exist. The phantom measurements showed slice thickness affected the accuracy of localization in the SI plane, and couch sag that occurs at the CT on rails gantry could not be totally corrected for in the AP plane. Other confounding factors are the action of rotating the couch and associated time lag between image acquisitions (prostate motion), EPI image quality, and outlining uncertainties.

  8. Comparison and Consensus Guidelines for Delineation of Clinical Target Volume for CT- and MR-Based Brachytherapy in Locally Advanced Cervical Cancer

    SciTech Connect

    Viswanathan, Akila N.; Gaffney, David K.; Beriwal, Sushil; Bhatia, Sudershan K.; Lee Burnett, Omer; D'Souza, David P.; Patil, Nikhilesh; Haddock, Michael G.; Jhingran, Anuja; Jones, Ellen L.; Kunos, Charles A.; Lee, Larissa J.; Mayr, Nina A.; Petersen, Ivy; Petric, Primoz; Portelance, Lorraine; Small, William; Strauss, Jonathan B.; and others

    2014-10-01

    Objective: To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3-Tesla (3-T) magnetic resonance (MR) image-based cervical-cancer brachytherapy. Methods and Materials: Twenty-three experts in gynecologic radiation oncology contoured the same 3 cervical cancer brachytherapy cases: 1 stage IIB near-complete response (CR) case with a tandem and ovoid, 1 stage IIB partial response (PR) case with tandem and ovoid with needles, and 1 stage IB2 CR case with a tandem and ring applicator. The CT contours were completed before the MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with κ statistics as a measure of agreement between participants. The conformity index was calculated for each of the 6 data sets. Dice coefficients were generated to compare the CT and MR contours of the same case. Results: For all 3 cases, the mean tumor volume was smaller on MR than on CT (P<.001). The κ and conformity index estimates were slightly higher for CT, indicating a higher level of agreement on CT. The Dice coefficients were 89% for the stage IB2 case with a CR, 74% for the stage IIB case with a PR, and 57% for the stage IIB case with a CR. Conclusion: In a comparison of MR-contoured with CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast medium visible on the images at the time of brachytherapy. MR at the time of brachytherapy may be of greatest benefit in patients with large tumors with parametrial extension that have a partial or complete response to external beam. On the basis of these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at (http://www.nrgoncology.org/Resources/ContouringAtlases/GYNCervicalBrachytherapy.aspx)

  9. Comparison of the effectiveness of different immobilization systems in different body regions using daily megavoltage CT in helical tomotherapy

    PubMed Central

    Cheng, K-F

    2014-01-01

    Objective: Effective immobilization is crucial for the accurate delivery of radiotherapy. This study aimed to compare the effectiveness of the commonly used immobilization systems for different body regions using megavoltage CT (MVCT). Methods: Daily treatment set-up data from 212 patients treated by helical tomotherapy (Accuray, Sunnyvale, CA) in 6 body regions (52 head and neck, 41 chest, 38 abdomen, 36 pelvis, 18 breast and 27 cranium) were obtained. Based on a verification tool using the pre-treatment MVCT, set-up corrections for each patient were recorded. Mean systematic and random errors of lateral, longitudinal, vertical and roll directions and three-dimensional vectors were compared between immobilization systems of each region. Results: Smaller set-up deviations were observed in the Orfit system (Orfit Industries NV, Wijnegem, Belgium) of the head and neck region, while the performance of immobilization systems for the chest, abdomen and pelvis regions was similar. Larger differences were noted in the breast group, where the prone BodyFIX® system (Medical Intelligence, Medizintechnik GmbH, Schwabmünchen, Germany) was less stable than the supine VacLok® system (CIVCO Medical Solutions, Orange City, IA). Conclusion: Differences were found between the immobilization systems in the head and neck region, in which the Orfit system was relatively more effective, whereas the VacLok and BodyFIX systems performed similarly in the chest, abdomen and pelvis regions. For the breast case, the supine position with VacLok was much more stable than the prone breast technique. The results provided references for the estimation of clinical target volume–planning target volume margins. Advances in knowledge: This is the first article on comprehensive comparisons performed in immobilization systems for main body regions that provides some practical recommendations. PMID:24398111

  10. A respiratory-gated micro-CT comparison of respiratory patterns in free-breathing and mechanically ventilated rats.

    PubMed

    Ford, Nancy L; McCaig, Lynda; Jeklin, Andrew; Lewis, James F; Veldhuizen, Ruud A W; Holdsworth, David W; Drangova, Maria

    2017-01-01

    In this study, we aim to quantify the differences in lung metrics measured in free-breathing and mechanically ventilated rodents using respiratory-gated micro-computed tomography. Healthy male Sprague-Dawley rats were anesthetized with ketamine/xylazine and scanned with a retrospective respiratory gating protocol on a GE Locus Ultra micro-CT scanner. Each animal was scanned while free-breathing, then intubated and mechanically ventilated (MV) and rescanned with a standard ventilation protocol (56 bpm, 8 mL/kg and PEEP of 5 cm H2O) and again with a ventilation protocol that approximates the free-breathing parameters (88 bpm, 2.14 mL/kg and PEEP of 2.5 cm H2O). Images were reconstructed representing inspiration and end expiration with 0.15 mm voxel spacing. Image-based measurements of the lung lengths, airway diameters, lung volume, and air content were compared and used to calculate the functional residual capacity (FRC) and tidal volume. Images acquired during MV appeared darker in the airspaces and the airways appeared larger. Image-based measurements showed an increase in lung volume and air content during standard MV, for both respiratory phases, compared with matched MV and free-breathing. Comparisons of the functional metrics showed an increase in FRC for mechanically ventilated rats, but only the standard MV exhibited a significantly higher tidal volume than free-breathing or matched MV Although standard mechanical ventilation protocols may be useful in promoting consistent respiratory patterns, the amount of air in the lungs is higher than in free-breathing animals. Matching the respiratory patterns with the free-breathing case allowed similar lung morphology and physiology measurements while reducing the variability in the measurements.

  11. Relevance of indirect comparisons in the German early benefit assessment and in comparison to HTA processes in England, France and Scotland.

    PubMed

    Lebioda, Andrea; Gasche, David; Dippel, Franz-Werner; Theobald, Karlheinz; Plantör, Stefan

    2014-12-01

    Early benefit assessment in Germany under the legislative framework of AMNOG (Arzneimittelmarktneuordnungsgesetz) requires direct comparisons of the new drug with appropriate comparators determined by the Federal Joint Committee (G-BA). In case no head-to-head studies are available for direct comparisons, the submission of indirect comparisons is permitted to assess the additional benefit of the new drug. However, the Institute for Quality and Efficiency in Health Care (IQWiG) states a clear preference for head-to-head trials and defines strict requirements for indirect comparisons to be considered in the benefit assessment. Similar requirements also exist in other countries with mandatory health technology assessments (HTA), like France, England and Scotland. Our evaluation shows that a comparison of the different HTA regarding indirect comparisons is difficult. Overall, external preconditions and methodological requirements are demanding and hardly to fulfill by pharmaceutical companies for implementation of indirect comparisons in early benefit assessment. The determination of the appropriate comparators, outcomes, patient subgroups and study choice are the main target within indirect comparisons for the future. To compare and assess submitted indirect comparisons it would be desirable that a transparent process was established, including the mandatory publication of HTA-reports within Europe and international guidelines, accepted by a large number of HTA-agencies.

  12. Can MRI accurately detect pilon articular malreduction? A quantitative comparison between CT and 3T MRI bone models

    PubMed Central

    Radzi, Shairah; Dlaska, Constantin Edmond; Cowin, Gary; Robinson, Mark; Pratap, Jit; Schuetz, Michael Andreas; Mishra, Sanjay

    2016-01-01

    Background Pilon fracture reduction is a challenging surgery. Radiographs are commonly used to assess the quality of reduction, but are limited in revealing the remaining bone incongruities. The study aimed to develop a method in quantifying articular malreductions using 3D computed tomography (CT) and magnetic resonance imaging (MRI) models. Methods CT and MRI data were acquired using three pairs of human cadaveric ankle specimens. Common tibial pilon fractures were simulated by performing osteotomies to the ankle specimens. Five of the created fractures [three AO type-B (43-B1), and two AO type-C (43-C1) fractures] were then reduced and stabilised using titanium implants, then rescanned. All datasets were reconstructed into CT and MRI models, and were analysed in regards to intra-articular steps and gaps, surface deviations, malrotations and maltranslations of the bone fragments. Results Initial results reveal that type B fracture CT and MRI models differed by ~0.2 (step), ~0.18 (surface deviations), ~0.56° (rotation) and ~0.4 mm (translation). Type C fracture MRI models showed metal artefacts extending to the articular surface, thus unsuitable for analysis. Type C fracture CT models differed from their CT and MRI contralateral models by ~0.15 (surface deviation), ~1.63° (rotation) and ~0.4 mm (translation). Conclusions Type B fracture MRI models were comparable to CT and may potentially be used for the postoperative assessment of articular reduction on a case-to-case basis. PMID:28090442

  13. SU-E-P-11: Comparison of Image Quality and Radiation Dose Between Different Scanner System in Routine Abdomen CT

    SciTech Connect

    Liao, S; Wang, Y; Weng, H

    2015-06-15

    Purpose To evaluate image quality and radiation dose of routine abdomen computed tomography exam with the automatic current modulation technique (ATCM) performed in two different brand 64-slice CT scanners in our site. Materials and Methods A retrospective review of routine abdomen CT exam performed with two scanners; scanner A and scanner B in our site. To calculate standard deviation of the portal hepatic level with a region of interest of 12.5 mm x 12.5mm represented to the image noise. The radiation dose was obtained from CT DICOM image information. Using Computed tomography dose index volume (CTDIv) to represented CT radiation dose. The patient data in this study were with normal weight (about 65–75 Kg). Results The standard deviation of Scanner A was smaller than scanner B, the scanner A might with better image quality than scanner B. On the other hand, the radiation dose of scanner A was higher than scanner B(about higher 50–60%) with ATCM. Both of them, the radiation dose was under diagnostic reference level. Conclusion The ATCM systems in modern CT scanners can contribute a significant reduction in radiation dose to the patient. But the reduction by ATCM systems from different CT scanner manufacturers has slightly variation. Whatever CT scanner we use, it is necessary to find the acceptable threshold of image quality with the minimum possible radiation exposure to the patient in agreement with the ALARA principle.

  14. Three-dimensional visual truth of the normal airway tree for use as a quantitative comparison to micro-CT reconstructions

    NASA Astrophysics Data System (ADS)

    Thiesse, Jacqueline; Reinhardt, Joseph M.; de Ryk, Jessica; Namati, Eman; Leinen, Jessica; Recheis, Wolfgang A.; Hoffman, Eric A.; McLennan, Geoffrey

    2005-04-01

    Mouse models are important for pulmonary research to gain insight into structure and function in normal and diseased states, thereby extending knowledge of human disease conditions. The flexibility of human disease induction into mice, due to their similar genome, along with their short gestation cycle makes mouse models highly suitable as investigative tools. Advancements in non-invasive imaging technology, with the development of micro-computed tomography (μ-CT), have aided representation of disease states in these small pulmonary system models. The generation ofμCT 3D airway reconstructions has to date provided a means to examine structural changes associated with disease. The degree of accuracy ofμCT is uncertain. Consequently, the reliability of quantitative measurements is questionable. We have developed a method of sectioning and imaging the whole mouse lung using the Large Image Microscope Array (LIMA) as the gold standard for comparison. Fixed normal mouse lungs were embedded in agarose and 250μm sections of tissue were removed while the remaining tissue block was imaged with a stereomicroscope. A complete dataset of the mouse lung was acquired in this fashion. Following planar image registration, the airways were manually segmented using an in-house built software program PASS. Amira was then used render the 3D isosurface from the segmentations. The resulting 3D model of the normal mouse airway tree developed from pathology images was then quantitatively assessed and used as the standard to compare the accuracy of structural measurements obtained from μ-CT.

  15. Emphysema quantification from CT scans using novel application of diaphragm curvature estimation: comparison with standard quantification methods and pulmonary function data

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Yankelevitz, David F.; Henschke, Claudia I.; Barr, R. Graham

    2009-02-01

    Emphysema is a disease of the lungs that destroys the alveolar air sacs and induces long-term respiratory dysfunction. CT scans allow for the imaging of the anatomical basis of emphysema and quantification of the underlying disease state. Several measures have been introduced for the quantification emphysema directly from CT data; most,however, are based on the analysis of density information provided by the CT scans, which vary by scanner and can be hard to standardize across sites and time. Given that one of the anatomical variations associated with the progression of emphysema is the flatting of the diaphragm due to the loss of elasticity in the lung parenchyma, curvature analysis of the diaphragm would provide information about emphysema from CT. Therefore, we propose a new, non-density based measure of the curvature of the diaphragm that would allow for further quantification methods in a robust manner. To evaluate the new method, 24 whole-lung scans were analyzed using the ratios of the lung height and diaphragm width to diaphragm height as curvature estimates as well as using the emphysema index as comparison. Pearson correlation coefficients showed a strong trend of several of the proposed diaphragm curvature measures to have higher correlations, of up to r=0.57, with DLCO% and VA than did the emphysema index. Furthermore, we found emphysema index to have only a 0.27 correlation to the proposed measures, indicating that the proposed measures evaluate different aspects of the disease.

  16. Region of interest (ROI) computed tomography (CT): Comparison with full field of view (FFOV) and truncated CT for a human head phantom.

    PubMed

    Chityala, R; Hoffmann, K R; Rudin, S; Bednarek, D R

    2005-01-01

    Cone-beam CT reconstruction can be performed at lower integral dose, by using a non-uniform beam filter between the x-ray source and the patient to obtain good image quality within an ROI with minimal artifacts. To evaluate the method, a human head phantom was placed on a rotary stage. Cone-beam projection images of the phantom were obtained with and without an ROI filter (dose reduction factor ~7). A mapping function was established to equalize the intensity outside the ROI (to compensate for the attenuation by the filter) to the intensity inside by assuming that those features lying both inside and outside very close to the edge of the ROI are the same. Reconstructed images were obtained using equalized projection images for 2 cases: one in which the outside region was smoothed using an averaging filter and the other with no smoothing outside. In addition, a third case was simulated by calculating the average pixel value inside the ROI for each image and assigning this value to all pixels outside the ROI for that image. The images were then back projected using a Feldkamp algorithm. We found that the three cases yield results inside the ROI comparable to those obtained using FFOV projections. In addition, the ROI filter reconstruction with smoothing provides image information outside the ROI comparable to the FFOV reconstruction. CT using an ROI filter provides a means to reconstruct reliable 3D for a volume of interest with greatly reduced integral dose compared to FFOV projections and with minimal artifacts.

  17. Voxel-Based Sensitivity of Flat-Panel CT for the Detection of Intracranial Hemorrhage: Comparison to Multi-Detector CT

    PubMed Central

    Frölich, Andreas M.; Buhk, Jan-Hendrik; Fiehler, Jens; Kemmling, Andre

    2016-01-01

    Objectives Flat-panel CT (FPCT) allows cross-sectional parenchymal, vascular and perfusion imaging within the angiography suite, which could greatly facilitate acute stroke management. We hypothesized that FPCT offers equal diagnostic accuracy compared to multi-detector CT (MDCT) as a primary tool to exclude intracranial hemorrhage. Methods 22 patients with intracranial hematomas who had both MDCT and FPCT performed within 24 hours were retrospectively identified. Patients with visible change in hematoma size or configuration were excluded. Two raters independently segmented hemorrhagic lesions. Data sets and corresponding binary lesion maps were co-registered to compare hematoma volume. Diagnostic accuracy of FPCT to detect hemorrhage was calculated from voxel-wise analysis of lesion overlap compared to reference MDCT. Results Mean hematoma size was similar between MDCT (16.2±8.9 ml) and FPCT (16.1±8.6 ml), with near perfect correlation of hematoma sizes between modalities (ρ = 0.95, p<0.001). Sensitivity and specificity of FPCT to detect hemorrhagic voxels was 61.6% and 99.8% for intraventricular hematomas and 67.7% and 99.5% for all other intracranial hematomas. Conclusions In this small sample containing predominantly cases with subarachnoid hemorrhage, FPCT based assessment of hemorrhagic volume in brain yields acceptable accuracy compared to reference MDCT, albeit with a limited sensitivity on a voxel level. Further assessment and improvement of FPCT is necessary before it can be applied as a primary imaging modality to exclude intracranial hemorrhage in acute stroke patients. PMID:27806106

  18. Ct shift: A novel and accurate real-time PCR quantification model for direct comparison of different nucleic acid sequences and its application for transposon quantifications.

    PubMed

    Kolacsek, Orsolya; Pergel, Enikő; Varga, Nóra; Apáti, Ágota; Orbán, Tamás I

    2017-01-20

    There are numerous applications of quantitative PCR for both diagnostic and basic research. As in many other techniques the basis of quantification is that comparisons are made between different (unknown and known or reference) specimens of the same entity. When the aim is to compare real quantities of different species in samples, one cannot escape their separate precise absolute quantification. We have established a simple and reliable method for this purpose (Ct shift method) which combines the absolute and the relative approach. It requires a plasmid standard containing both sequences of amplicons to be compared (e.g. the target of interest and the endogenous control). It can serve as a reference sample with equal copies of templates for both targets. Using the ΔΔCt formula we can quantify the exact ratio of the two templates in each unknown sample. The Ct shift method has been successfully applied for transposon gene copy measurements, as well as for comparison of different mRNAs in cDNA samples. This study provides the proof of concept and introduces some potential applications of the method; the absolute nature of results even without the need for real reference samples can contribute to the universality of the method and comparability of different studies.

  19. Comparison of Scientific Calipers and Computer-Enabled CT Review for the Measurement of Skull Base and Craniomaxillofacial Dimensions

    PubMed Central

    Citardi, Martin J.; Herrmann, Brian; Hollenbeak, Chris S.; Stack, Brendan C.; Cooper, Margaret; Bucholz, Richard D.

    2001-01-01

    Traditionally, cadaveric studies and plain-film cephalometrics provided information about craniomaxillofacial proportions and measurements; however, advances in computer technology now permit software-based review of computed tomography (CT)-based models. Distances between standardized anatomic points were measured on five dried human skulls with standard scientific calipers (Geneva Gauge, Albany, NY) and through computer workstation (StealthStation 2.6.4, Medtronic Surgical Navigation Technology, Louisville, CO) review of corresponding CT scans. Differences in measurements between the caliper and CT model were not statistically significant for each parameter. Measurements obtained by computer workstation CT review of the cranial skull base are an accurate representation of actual bony anatomy. Such information has important implications for surgical planning and clinical research. ImagesFigure 1Figure 2Figure 3 PMID:17167599

  20. Computerized lung nodule detection: comparison of performance for low-dose and standard-dose helical CT scans

    NASA Astrophysics Data System (ADS)

    Armato, Samuel G., III; Giger, Maryellen L.; Doi, Kunio; Bick, Ulrich; MacMahon, Heber

    2001-07-01

    The vast amount of image data acquired during a computed tomography (CT) scan makes lung nodule detection a burdensome task. Moreover, the growing acceptance of low-dose CT for lung cancer screening promises to further impact radiologists' workloads. Therefore, we have developed a computerized method to automatically analyze structures within a CT scan and identify those structures that represent lung nodules. Gray-level thresholding is performed to segment the lungs in each section to produce a segmented lung volume, which is then iteratively thresholded. At each iteration, remaining voxels are grouped into contiguous three-dimensional structures. Structures that satisfy a volume criterion then become nodule candidates. The set of nodule candidates is subjected to feature analysis. To distinguish candidates representing nodule and non-nodule structures, a rule-based approach is combined with an automated classifier. This method was applied to 43 standard-dose (diagnostic) CT scans and 13 low-dose CT scans. The method achieved an overall detection sensitivity of 71% with 1.5 false-positive detections per section on the standard-dose database and 71% sensitivity with 1.2 false-positive detections per section on the low-dose database. This automated method demonstrates promising performance in its ability to accurately detect lung nodules in standard-dose and low-dose CT images.

  1. Comparison of an alternative and existing binning methods to reduce the acquisition duration of 4D PET/CT

    SciTech Connect

    Didierlaurent, David Ribes, Sophie; Caselles, Olivier; Jaudet, Cyril; Dierickx, Lawrence O.; Zerdoud, Slimane; Brillouet, Severine; Weits, Kathleen; Batatia, Hadj; Courbon, Frédéric

    2014-11-01

    Purpose: Respiratory motion is a source of artifacts that reduce image quality in PET. Four dimensional (4D) PET/CT is one approach to overcome this problem. Existing techniques to limiting the effects of respiratory motions are based on prospective phase binning which requires a long acquisition duration (15–25 min). This time is uncomfortable for the patients and limits the clinical exploitation of 4D PET/CT. In this work, the authors evaluated an existing method and an alternative retrospective binning method to reduce the acquisition duration of 4D PET/CT. Methods: The authors studied an existing mixed-amplitude binning (MAB) method and an alternative binning method by mixed-phases (MPhB). Before implementing MPhB, they analyzed the regularity of the breathing patterns in patients. They studied the breathing signal drift and missing CT slices that could be challenging for implementing MAB. They compared the performance of MAB and MPhB with current binning methods to measure the maximum uptake, internal volume, and maximal range of tumor motion. Results: MPhB can be implemented depending on an optimal phase (in average, the exhalation peak phase −4.1% of the entire breathing cycle duration). Signal drift of patients was in average 35% relative to the breathing amplitude. Even after correcting this drift, MAB was feasible in 4D CT for only 64% of patients. No significant differences appeared between the different binning methods to measure the maximum uptake, internal volume, and maximal range of tumor motion. The authors also determined the inaccuracies of MAB and MPhB to measure the maximum amplitude of tumor motion with three bins (less than 3 mm for movement inferior to 12 mm, up to 6.4 mm for a 21 mm movement). Conclusions: The authors proposed an alternative binning method by mixed-phase binning that halves the acquisition duration of 4D PET/CT. Mixed-amplitude binning was challenging because of signal drift and missing CT slices. They showed that more

  2. [Comparison of a dental cone beam CT with a multi-detector row CT on effective doses and physical image quality].

    PubMed

    Yoshida, Yutaka; Tokumori, Kenji; Okamura, Kazutoshi; Yoshiura, Kazunori

    2011-01-01

    The purpose of this study was to compare a dental cone beam computed tomography (dental CBCT) and a multi-detector row CT (MDCT) using effective doses and physical image quality. A dental mode (D-mode) and an implant mode (I-mode) were employed for calculating effective doses. Field of view (FOV) size of the MDCT was 150 mm. Three types of images were obtained using 3 different reconstruction functions: FC1 (for abdomen images), FC30 (for internal ear and bone images) and FC81 (for high resolution images). Effective doses obtained with the D-mode and with the I-mode were about 20% and 50% of those obtained with the MDCT, respectively. Resolution properties obtained with the D-mode and I-mode were superior to that of the MDCT in a high frequency range. Noise properties of the D-mode and the I-mode were better than those with FC81. It was found that the dental CBCT has better potential as compared with MDCT in both dental and implant modes.

  3. Automated segmentation and tracking of coronary arteries in cardiac CT scans: comparison of performance with a clinically used commercial software

    NASA Astrophysics Data System (ADS)

    Zhou, Chuan; Chan, Heang-Ping; Chughtai, Aamer; Patel, Smita; Hadjiiski, Lubomir M.; Sahiner, Berkman; Wei, Jun; Kazerooni, Ella A.

    2010-03-01

    Coronary CT angiography (cCTA) has been reported to be an effective means for diagnosis of coronary artery disease. We are investigating the feasibility of developing a computer-aided detection (CADe) system to assist radiologists in detection of non-calcified plaques in coronary arteries in ECG-gated cCTA scans. In this study, we developed a prototype vessel segmentation and tracking method to extract the coronary arterial trees which will define the search space for plaque detection. Vascular structures are first enhanced by 3D multi-scale filtering and analysis of the eigenvalues of Hessian matrices using a vessel enhancement response function specifically designed for coronary arteries. The enhanced vascular structures are then segmented by an EM estimation method. The segmented coronary arteries are tracked using a 3D dynamic balloon tracking (DBT) method. For this preliminary study, two starting seed points were manually identified at the origins of the left and right coronary artery (LCA and RCA). The DBT method automatically moves a sphere along the vessel whose diameter is adjusted dynamically based on the local vessel size, tracks the vessels, and identifies its branches to generate the left and right coronary arterial trees. The algorithm was applied to 20 cCTA scans that contained various degrees of coronary artery diseases. To evaluate the performance of vessel segmentation and tracking, the rendered volume of coronary arteries tracked by our algorithm was displayed on a PC, placed next to a GE Advantage workstation on which the coronary arterial trees tracked by the GE software and the original cCTA scan were displayed. Two experienced thoracic radiologists visually examined the coronary arteries on the cCTA scan and the segmented vessels to count untracked false-negative (FN) segments and false positives (FPs). The comparison was made by radiologists' visual judgment because the digital files for the segmented vessels were not accessible on the

  4. SU-E-I-84: Accuracy Comparison of Multi-Modality Image-Based Volumes of Rodent Solid Tumors Using In-Air Micro-CT Image Volume

    SciTech Connect

    Lee, Y; Fullerton, G; Goins, B

    2015-06-15

    Purpose: Tumor volume is considered as a better predictor for therapy response monitoring and tumor staging over Response Evaluation Criteria In Solid Tumors (RECIST) or World Health Organization (WHO) criteria. In this study, the accuracy of subcutaneous rodent tumor volumes using preclinical magnetic resonance imaging (MRI), micro-computed tomography (micro-CT) and ultrasound (US) equipment and with an external caliper was compared using in-air micro-CT image volume of excised tumors determined as reference tumor volume in our prior study. Methods: MR, US and micro-CT images of subcutaneous SCC4 head and neck tumor xenografts were acquired 4, 6, 9, 11 and 13 days after tumor cell inoculation. Before MR and US scans, caliper measurements were made. After tumors were excised, in-air micro-CT imaging and ex vivo caliper measurements were performed. Tumor volumes were calculated using formula V = (π/6)*a*b*c where a, b and c are the maximum diameters in three perpendicular dimensions determined by the three image modalities and caliper, and compared with reference tumor volume by linear regression analysis as well as Bland-Altman plots. A one-way Analysis of Variance (ANOVA) test was also performed to compare volumes among caliper measurements. Results: The correlation coefficients (R2) of the regression lines for tumor volumes measured by the three imaging modalities and caliper were 0.9939, 0.9669, 0.9806, 0.9274, 0.9619 and 0.9819 for MRI, US and micro-CT, caliperbeforeMRI, caliperbeforeUS and ex vivo caliper respectively. In Bland-Altman plots, the average of tumor volume difference from reference tumor volume (bias) was significant for caliper and micro- CT, but not for MRI and US. Comparison of caliper measurements showed a significant difference (p < 0.05). Conclusion: Using the in-air micro-CT image volume, tumor volume measured by MRI was the most accurate among the three imaging modalities. In vivo caliper volume measurements showed unreliability while ex

  5. Comparison of CNG and LNG technologies for transportation applications. Final subcontract report, June 1991--December 1991

    SciTech Connect

    Sinor, J.E.

    1992-01-01

    This report provides a head-to-head comparison of compressed natural gas (CNG) and liquefied natural gas (LNG) supplied to heavy-duty vehicles. The comparison includes an assessment of the overall efficiency of the fuel delivery system, the cost of the fuel supply system, the efficiency of use in heavy-duty vehicles, and the environmental impact of each technology. The report concludes that there are applications in which CNG will have the advantage, and applications in which LNG will be preferred.

  6. Comparison between Pre-log and Post-log Statistical Models in Ultra-Low-Dose CT Reconstruction.

    PubMed

    Fu, Lin; Lee, Tzu-Cheng; Kim, Soo Mee; Alessio, Adam; Kinahan, Paul; Chang, Zhiqian; Sauer, Ken; Kalra, Mannudeep; De Man, Bruno

    2016-11-09

    X-ray detectors in clinical computed tomography (CT) usually operate in current-integrating mode. Their complicated signal statistics often lead to intractable likelihood functions for practical use in model-based image reconstruction (MBIR). It is therefore desirable to design simplified statistical models without losing the essential factors. Depending on whether the CT transmission data are logarithmically transformed, pre-log and post-log models are two major categories of choices in CT MBIR. Both being approximations, it remains an open question whether one model can notably improve image quality over the other on real scanners. In this study, we develop and compare several pre-log and post-log MBIR algorithms under a unified framework. Their reconstruction accuracy based on simulation and clinical datasets are evaluated. The results show that pre-log MBIR can achieve notably better quantitative accuracy than post-log MBIR in ultra-low-dose CT, although in less extreme cases, post-log MBIR with handcrafted pre-processing remains a competitive alternative. Pre-log MBIR could play a growing role in emerging ultra-low-dose CT applications.

  7. CT venography after knee replacement surgery: comparison of dual-energy CT-based monochromatic imaging and single-energy metal artifact reduction techniques on a 320-row CT scanner

    PubMed Central

    Utsunomiya, Daisuke; Oda, Seitaro; Nakaura, Takeshi; Funama, Yoshinori; Yuki, Hideaki; Hirata, Kenichiro; Hatemura, Masahiro; Namimoto, Tomohiro; Yamashita, Yasuyuki

    2017-01-01

    Background An optimal metal artifact reduction (MAR) technique is needed for a reliable and accurate image-based diagnosis. Purpose Using a 320-row scanner, we compared the dual-energy computed tomography (CT)-based monochromatic and the single-energy metal artifact reduction (SEMAR) techniques for CT venography (CTV) to identify the better imaging method for diagnosing deep vein thrombosis (DVT) in patients who had undergone knee replacement surgery. Material and Methods Twenty-three consecutive patients with suspected DVT after unilateral knee replacement surgery underwent dual-energy CT (135/80 kVp). Monochromatic images of 35–135 keV were generated; the monochromatic image with the best signal-to-noise ratio (SNR) of the popliteal vein near the metal prosthesis were selected. The projection data of 80 kVp were reconstructed using MAR algorithm. The mean SNR ON MAR and the best SNR ON monochromatic images were compared. Two radiologists evaluated visualization of the metal artifacts on a four-point scale where 1 = extensive artifacts, 2 = strong artifacts, 3 = mild artifacts, and 4 = minimal artifacts. Results The mean SNR was significantly higher on the MAR than the monochromatic images (12.8 ± 4.7 versus 7.7 ± 5.1, P < 0.01) and the visual scores were significantly higher for MAR than monochromatic images (2.6 ± 0.8 versus 1.3 ± 0.4, P < 0.01). Conclusion For CTV after knee replacement surgery, the MAR technique is superior to the monochromatic imaging technique. PMID:28321330

  8. The evaluation and comparison of kidney length obtained from axial cuts in spiral CT scan with its true length

    PubMed Central

    Karami, Mehdi; Rahimi, Farshad; Tajadini, Mohammadhasan

    2015-01-01

    Background: Increased size of kidney is the main symptom of pyelonephritis and renal ischemia in children. Ultrasound and computed tomography (CT) scan methods are the imaging methods for evaluating the urogenital system. The aim of this study is to compare the kidney length obtained from spiral CT scan with the true length obtained from multi-slice CT. Materials and Methods: From 100 patients 200 kidneys were examined in Alzahra Hospital in 2012. Multi-slice CT was used to obtain coronal and sagittal cuts to find the length of kidneys. Results: The mean values of true size of axial sections of the right and left kidneys were 108.37 ± 12.3 mm and 109.74 ± 13.6 mm, respectively. The mean difference of axial sections’ lengths in the right and left kidneys was 1.37 ± 1.22 mm. The mean values of length in the spiral CT scan of the right and left kidneys were 98.61 ± 15.8 mm and 103.11 ± 15.9 mm, respectively. The difference in the estimated size by multi-slice CT scan in oblique and axial images was significant (9.77 ± 1.19 mm and 6.63 ± 0.8 mm for the right and left kidneys, respectively (P < 0.001). Conclusion: The average size of both kidneys determined in axial images was smaller than the actual size. The estimation of kidney size in axial images is not reliable, and to obtain the actual size, it is required to have the coronal and sagittal cuts with proper quality, which could be achieved by multi-slice method. PMID:25709984

  9. Radiation absorbed from dental implant radiography: a comparison of linear tomography, CT scan, and panoramic and intra-oral techniques

    SciTech Connect

    Clark, D.E.; Danforth, R.A.; Barnes, R.W.; Burtch, M.L. )

    1990-01-01

    Absorbed radiation dose in bone marrow, thyroid, salivary gland, eye, and skin entrance was determined by placement of lithium fluoride thermoluminescent dosimeters (TLD's) at selected anatomical sites within and on a human-like x-ray phantom. The phantom was exposed to radiation from linear tomographic and computer-assisted tomographic (CT) simulated dental implant radiographic examinations. The mean dose was determined for each anatomical site. Resulting dose measurements from linear tomography and computer-assisted tomography are compared with reported panoramic and intra-oral doses. CT examination delivered the greatest dose, while linear tomography was generally lowest. Panoramic and intra-oral doses were similar to those of linear tomography.

  10. Comparison of quantitative myocardial perfusion imaging CT to fluorescent microsphere-based flow from high-resolution cryo-images

    NASA Astrophysics Data System (ADS)

    Eck, Brendan L.; Fahmi, Rachid; Levi, Jacob; Fares, Anas; Wu, Hao; Li, Yuemeng; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    Myocardial perfusion imaging using CT (MPI-CT) has the potential to provide quantitative measures of myocardial blood flow (MBF) which can aid the diagnosis of coronary artery disease. We evaluated the quantitative accuracy of MPI-CT in a porcine model of balloon-induced LAD coronary artery ischemia guided by fractional flow reserve (FFR). We quantified MBF at baseline (FFR=1.0) and under moderate ischemia (FFR=0.7) using MPI-CT and compared to fluorescent microsphere-based MBF from high-resolution cryo-images. Dynamic, contrast-enhanced CT images were obtained using a spectral detector CT (Philips Healthcare). Projection-based mono-energetic images were reconstructed and processed to obtain MBF. Three MBF quantification approaches were evaluated: singular value decomposition (SVD) with fixed Tikhonov regularization (ThSVD), SVD with regularization determined by the L-Curve criterion (LSVD), and Johnson-Wilson parameter estimation (JW). The three approaches over-estimated MBF compared to cryo-images. JW produced the most accurate MBF, with average error 33.3+/-19.2mL/min/100g, whereas LSVD and ThSVD had greater over-estimation, 59.5+/-28.3mL/min/100g and 78.3+/-25.6 mL/min/100g, respectively. Relative blood flow as assessed by a flow ratio of LAD-to-remote myocardium was strongly correlated between JW and cryo-imaging, with R2=0.97, compared to R2=0.88 and 0.78 for LSVD and ThSVD, respectively. We assessed tissue impulse response functions (IRFs) from each approach for sources of error. While JW was constrained to physiologic solutions, both LSVD and ThSVD produced IRFs with non-physiologic properties due to noise. The L-curve provided noise-adaptive regularization but did not eliminate non-physiologic IRF properties or optimize for MBF accuracy. These findings suggest that model-based MPI-CT approaches may be more appropriate for quantitative MBF estimation and that cryo-imaging can support the development of MPI-CT by providing spatial distributions of MBF.

  11. 68Ga-HBED-CC-PSMA PET/CT Versus Histopathology in Primary Localized Prostate Cancer: A Voxel-Wise Comparison

    PubMed Central

    Zamboglou, Constantinos; Schiller, Florian; Fechter, Tobias; Wieser, Gesche; Jilg, Cordula Annette; Chirindel, Alin; Salman, Nasr; Drendel, Vanessa; Werner, Martin; Mix, Michael; Meyer, Philipp Tobias; Grosu, Anca Ligia

    2016-01-01

    Purpose: We performed a voxel-wise comparison of 68Ga-HBED-CC-PSMA PET/CT with prostate histopathology to evaluate the performance of 68Ga-HBED-CC-PSMA for the detection and delineation of primary prostate cancer (PCa). Methodology: Nine patients with histopathological proven primary PCa underwent 68Ga-HBED-CC-PSMA PET/CT followed by radical prostatectomy. Resected prostates were scanned by ex-vivo CT in a special localizer and histopathologically prepared. Histopathological information was matched to ex-vivo CT. PCa volume (PCa-histo) and non-PCa tissue in the prostate (NPCa-histo) were processed to obtain a PCa-model, which was adjusted to PET-resolution (histo-PET). Each histo-PET was coregistered to in-vivo PSMA-PET/CT data. Results: Analysis of spatial overlap between histo-PET and PSMA PET revealed highly significant correlations (p < 10-5) in nine patients and moderate to high coefficients of determination (R²) from 42 to 82 % with an average of 60 ± 14 % in eight patients (in one patient R2 = 7 %). Mean SUVmean in PCa-histo and NPCa-histo was 5.6 ± 6.1 and 3.3 ± 2.5 (p = 0.012). Voxel-wise receiver-operating characteristic (ROC) analyses comparing the prediction by PSMA-PET with the non-smoothed tumor distribution from histopathology yielded an average area under the curve of 0.83 ± 0.12. Absolute and relative SUV (normalized to SUVmax) thresholds for achieving at least 90 % sensitivity were 3.19 ± 3.35 and 0.28 ± 0.09, respectively. Conclusions: Voxel-wise analyses revealed good correlations of 68Ga-HBED-CC-PSMA PET/CT and histopathology in eight out of nine patients. Thus, PSMA-PET allows a reliable detection and delineation of PCa as basis for PET-guided focal therapies. PMID:27446496

  12. Evaluation of biventricular ejection fraction with ECG-gated 16-slice CT: preliminary findings in acute pulmonary embolism in comparison with radionuclide ventriculography.

    PubMed

    Coche, Emmanuel; Vlassenbroek, Alain; Roelants, Véronique; D'Hoore, William; Verschuren, Franck; Goncette, Louis; Maldague, Baudouin

    2005-07-01

    This study aimed to assess the feasibility of cardiac global function evaluation during a whole-chest multi-slice CT (MSCT) acquisition in patients referred for suspicion of pulmonary embolism (PE), and to compare the results with planar equilibrium radionuclide ventriculography (ERNA). Ten consecutive haemodynamically stable patients (six female, four male; mean age 69.7 years; heart rate 65-99 bpm) with suspicion of PE underwent an MSCT and ERNA within a 6 h period. CT acquisition was performed after contrast medium injection by using 16x1.5 mm collimation and retrospective ECG gating. Left ventricular (LVEF) and right ventricular (RVEF) ejection fractions were calculated using dedicated three-dimensional software. Relationships between measurements obtained with MSCT and ERNA were assessed using linear regression analysis and reliability of MSCT was assessed with intra-class correlation coefficient. Bland-Altman analysis was performed to calculate limits of agreement between MSCT and ERNA. MSCT was performed successfully in ten patients with a mean acquisition time of 16.5+/-2.8 s. Functional cardiac evaluation was possible on CT for all patients except for one due to poor opacification of right ventricle. Linear regression analysis showed a good correlation between MSCT and ERNA for the LVEF (R=0.91) and the RVEF (R=0.89) measurements. Intra-class correlation was superior for LVEF (0.92) than for the RVEF (0.68). Bland-Altman plots demonstrated that MSCT substantially overestimated the ERNA RVEF. Morphological CT data demonstrated PE in four of ten of patients and alternative diagnoses in five of ten patients. Our study reveals that MSCT with retrospective ECG gating may provide in one modality a morphological and a functional cardiopulmonary evaluation. Comparison with ERNA demonstrated a good correlation for both ventricular ejection fractions.

  13. Comparison of patient specific dose metrics between chest radiography, tomosynthesis, and CT for adult patients of wide ranging body habitus

    SciTech Connect

    Zhang, Yakun; Li, Xiang; Segars, W. Paul; Samei, Ehsan

    2014-02-15

    Purpose: Given the radiation concerns inherent to the x-ray modalities, accurately estimating the radiation doses that patients receive during different imaging modalities is crucial. This study estimated organ doses, effective doses, and risk indices for the three clinical chest x-ray imaging techniques (chest radiography, tomosynthesis, and CT) using 59 anatomically variable voxelized phantoms and Monte Carlo simulation methods. Methods: A total of 59 computational anthropomorphic male and female extended cardiac-torso (XCAT) adult phantoms were used in this study. Organ doses and effective doses were estimated for a clinical radiography system with the capability of conducting chest radiography and tomosynthesis (Definium 8000, VolumeRAD, GE Healthcare) and a clinical CT system (LightSpeed VCT, GE Healthcare). A Monte Carlo dose simulation program (PENELOPE, version 2006, Universitat de Barcelona, Spain) was used to mimic these two clinical systems. The Duke University (Durham, NC) technique charts were used to determine the clinical techniques for the radiographic modalities. An exponential relationship between CTDI{sub vol} and patient diameter was used to determine the absolute dose values for CT. The simulations of the two clinical systems compute organ and tissue doses, which were then used to calculate effective dose and risk index. The calculation of the two dose metrics used the tissue weighting factors from ICRP Publication 103 and BEIR VII report. Results: The average effective dose of the chest posteroanterior examination was found to be 0.04 mSv, which was 1.3% that of the chest CT examination. The average effective dose of the chest tomosynthesis examination was found to be about ten times that of the chest posteroanterior examination and about 12% that of the chest CT examination. With increasing patient average chest diameter, both the effective dose and risk index for CT increased considerably in an exponential fashion, while these two dose

  14. Real medical benefit assessed by indirect comparison.

    PubMed

    Falissard, Bruno; Zylberman, Myriam; Cucherat, Michel; Izard, Valérie; Meyer, François

    2009-01-01

    Frequently, in data packages submitted for Marketing Approval to the CHMP, there is a lack of relevant head-to-head comparisons of medicinal products that could enable national authorities responsible for the approval of reimbursement to assess the Added Therapeutic Value (ASMR) of new clinical entities or line extensions of existing therapies.Indirect or mixed treatment comparisons (MTC) are methods stemming from the field of meta-analysis that have been designed to tackle this problem. Adjusted indirect comparisons, meta-regressions, mixed models, Bayesian network analyses pool results of randomised controlled trials (RCTs), enabling a quantitative synthesis.The REAL procedure, recently developed by the HAS (French National Authority for Health), is a mixture of an MTC and effect model based on expert opinions. It is intended to translate the efficacy observed in the trials into effectiveness expected in day-to-day clinical practice in France.

  15. In-vivo Comparison of 18F-FLT uptake, CT Number, Tumor Volume in Evaluation of Repopulation during Radiotherapy for Lung cancer

    PubMed Central

    Zhang, Xiaoli; Yu, Jinming; Li, Chengming; Sun, Xindong; Meng, Xue

    2017-01-01

    Accelerated repopulation has been observed in various tumors. This study was aimed to evaluate the potential of 3′-deoxy-3′-18F-fluorothymidine (18F-FLT) uptake and Computed Tomography Number (CTN) in monitoring tumor responses to radiotherapy compared with tumor volume (TV) changes. Tumor bearing nude mice were assigned to either irradiated daily or every second day group and then randomized to 6 sub-groups to receive 0Gy, 6Gy, 12Gy, 18Gy, 24Gy, 36Gy irradiation, respectively. TV was measured every 3 days. 18F-FLT micro-PET/CT scans were performed after irradiation being completed. Tumor sections were stained to calculate the immunohistochemical (Ki-67) labeling index (LI). Comparison analysis between FLT uptake parameters, CTNs, VTs and Ki-67 LI results were conducted to determine the correlation. Ki-67 LI increased significantly after 6 times of irradiation at irradiated daily group and after 3 times at irradiated every second day group, suggesting accelerated repopulation. No shrinkage of TV was noticed at two groups during irradiation delivery. Both 18F-FLT uptake and CTN increased significantly after irradiation of 12Gy/6f/6d and 6Gy/3f/6d. Comparison analysis found a significant relationship between Ki-67 LI and 18F-FLT uptake parameters as well as CTN. Both 18F-FLT PET and CT have the potential to reflect the tumor proliferative response during radiation delivery. PMID:28387306

  16. Comparison of analytical and numerical approaches for CT-based aberration correction in transcranial passive acoustic imaging

    NASA Astrophysics Data System (ADS)

    Jones, Ryan M.; Hynynen, Kullervo

    2016-01-01

    Computed tomography (CT)-based aberration corrections are employed in transcranial ultrasound both for therapy and imaging. In this study, analytical and numerical approaches for calculating aberration corrections based on CT data were compared, with a particular focus on their application to transcranial passive imaging. Two models were investigated: a three-dimensional full-wave numerical model (Connor and Hynynen 2004 IEEE Trans. Biomed. Eng. 51 1693-706) based on the Westervelt equation, and an analytical method (Clement and Hynynen 2002 Ultrasound Med. Biol. 28 617-24) similar to that currently employed by commercial brain therapy systems. Trans-skull time delay corrections calculated from each model were applied to data acquired by a sparse hemispherical (30 cm diameter) receiver array (128 piezoceramic discs: 2.5 mm diameter, 612 kHz center frequency) passively listening through ex vivo human skullcaps (n  =  4) to emissions from a narrow-band, fixed source emitter (1 mm diameter, 516 kHz center frequency). Measurements were taken at various locations within the cranial cavity by moving the source around the field using a three-axis positioning system. Images generated through passive beamforming using CT-based skull corrections were compared with those obtained through an invasive source-based approach, as well as images formed without skull corrections, using the main lobe volume, positional shift, peak sidelobe ratio, and image signal-to-noise ratio as metrics for image quality. For each CT-based model, corrections achieved by allowing for heterogeneous skull acoustical parameters in simulation outperformed the corresponding case where homogeneous parameters were assumed. Of the CT-based methods investigated, the full-wave model provided the best imaging results at the cost of computational complexity. These results highlight the importance of accurately modeling trans-skull propagation when calculating CT-based aberration corrections

  17. CT Scans

    MedlinePlus

    ... cross-sectional pictures of your body. Doctors use CT scans to look for Broken bones Cancers Blood clots Signs of heart disease Internal bleeding During a CT scan, you lie still on a table. The table ...

  18. TU-EF-304-06: A Comparison of CT Number to Relative Linear Stopping Power Conversion Curves Used by Proton Therapy Centers

    SciTech Connect

    Taylor, P; Lowenstein, J; Kry, S; Ibbott, G; Followill, D

    2015-06-15

    Purpose: To compare the CT Number (CTN) to Relative Linear Stopping Power (RLSP) conversion curves used by 14 proton institutions in their dose calculations. Methods: The proton institution’s CTN to RLSP conversion curves were collected by the Imaging and Radiation Oncology Core (IROC) Houston QA Center during its on-site dosimetry review audits. The CTN values were converted to scaled CT Numbers. The scaling assigns a CTN of 0 to air and 1000 to water to allow intercomparison. The conversion curves were compared and the mean curve was calculated based on institutions’ predicted RLSP values for air (CTN 0), lung (CTN 250), fat (CTN 950), water (1000), liver (CTN 1050), and bone (CTN 2000) points. Results: One institution’s curve was found to have a unique curve shape between the scaled CTN of 1025 to 1225. This institution modified its curve based on the findings. Another institution had higher RLSP values than expected for both low and high CTNs. This institution recalibrated their two CT scanners and the new data placed their curve closer to the mean of all institutions. After corrections were made to several conversion curves, four institutions still fall outside 2 standard deviations at very low CTNs (100–200), and two institutions fall outside between CTN 850–900. The largest percent difference in RLSP values between institutions for the specific tissues reviewed was 22% for the lung point. Conclusion: The review and comparison of CTN to RLSP conversion curves allows IROC Houston to identify any outliers and make recommendations for improvement. Several institutions improved their clinical dose calculation accuracy as a Result of this review. There is still area for improvement, particularly in the lung area of the curve. The IROC Houston QA Center is supported by NCI grant CA180803.

  19. Three-dimensional spiral CT angiography in pancreatic surgical planning using non-tailored protocols: comparison with conventional angiography.

    PubMed

    Blomley, M J; Albrecht, T; Williamson, R C; Allison, D J

    1998-03-01

    The aim of this study was to investigate three-dimensional spiral computed tomography (3DCT) as an adjunct to routine pancreatic CT scanning, with particular regard to the identification of surgically important hepatic arterial anomalies, correlated with conventional visceral angiography. 32 patients underwent spiral CT scans prior to pancreatic surgery using established protocols. Oral contrast medium was used throughout. 150 ml of intravenous contrast medium was given at 3 ml s-1 with a 24 s spiral CT sequence starting 35 s after the start of infusion. Two protocols were employed, both with a pitch of 1:3 mm table feed/collimation (n = 17) and 5 mm table feed/collimation (n = 15). Overlapping (1 mm minimum) axial reformats were reconstructed. 3DCT shaded-surface displays of the visceral arteries were assessed for visceral arterial anomalies. Visceral angiography (n = 23) was independently correlated. Satisfactory 3D angiograms were performed in all but one patient, in whom the coeliac axis was missed. (i) 3 mm protocol: 3DCT (n = 17) showed three anomalous right hepatic arteries (ARHA), one trifurcation anomaly and one splenic artery with an aortic origin. Angiography (n = 11) confirmed these findings, although one patient with an ARHA did not have angiography. A left gastric arterial supply to the left liver was not detected. (ii) 5 mm protocol: 3DCT (n = 15) showed two cases of ARHA. While confirming these findings, angiography (n = 12) showed a third case of ARHA, in which the coeliac and superior mesenteric artery had very close origins. A left gastric supply to the left liver was also missed. It is concluded that satisfactory 3DCT is possible without changing existing scanning protocols, although narrow sections are required for the confident assessment of right hepatic arterial anomalies, and any left hepatic supply via the left gastric artery was poorly assessed in this series.

  20. An in vitro CT Comparison of Gutta-Percha Removal with Two Rotary Systems and Hedstrom Files

    PubMed Central

    Yadav, Pankaj; Bharath, Makonahalli Jaganath; Sahadev, Chickmagravalli Krishnegowda; Makonahalli Ramachandra, Praveen Kumar; Rao, Yogesh; Ali, Ambereen; Mohamed, Shahnawaz

    2013-01-01

    Introduction To evaluate the efficacy of NiTi mechanical rotary instrumentation and Hedstrom file for gutta-percha/sealer removal computed tomography (CT) was utilized in vitro. Materials and Methods Thirty extracted human single rooted teeth, each with a single canal were selected. The samples were decoronated with a double faced diamond disk to have 17-mm root; teeth roots were instrumented with K-files up to master apical file #30 using step back technique. Samples were obturated using cold lateral condensation of gutta-percha and AH Plus root canal sealer. The teeth were then randomly divided into three groups of 10 specimens each. After 2 weeks 3-dimensional images of the roots were obtained by CT and the volume of root filling mass was measured. All the canals were then retreated by either the ProTaper retreatment files, Mtwo retreatment files or Hedstrom files. The canals were irrigated with 2 mL of 2.5% sodium hypochlorite irrigating solution during each change of instrument. The volume of remaining filling materials after the retreatment procedures was assessed by CT. Statistical analysis was performed with one-way ANOVA and Tukey’s post hoc test. Results Neither of studied systems completely removed the root filling material. No significant difference was observed between the rotary systems. The volume of remaining filling materials was significantly less in rotary instrumentation than hand files. There was no significant difference for debris extruded from the apical foramen between the groups. Conclusion Under the experimental conditions, Mtwo and ProTaper retreatment files left less gutta-percha and sealer than H files; however, complete removal of filling materials was not achieved by the three systems investigated. PMID:23717331

  1. Simultaneous measurements of cerebral blood flow by the xenon/CT method and the microsphere method. A comparison

    SciTech Connect

    Gur, D.; Yonas, H.; Jackson, D.L.; Wolfson, S.K. Jr.; Rockette, H.; Good, W.F.; Cook, E.E.; Arena, V.C.; Willy, J.A.; Maitz, G.S.

    1985-10-01

    Simultaneous measurements of cerebral blood flow have been performed in baboons to assess the correlation between the acute and invasive nondiffusible microsphere technique and the noninvasive xenon-enhanced CT method. Blood flows in small tissue volumes (approximately 1 cm3) were directly compared. The results of these studies demonstrate a statistically significant association between the two methods (P less than .001). Similar correlations were obtained by both the Kendall tau (tau) and the Spearman (r) methods. The problems and limitations of such correlations are discussed.

  2. A comparison between amplitude sorting and phase-angle sorting using external respiratory measurement for 4D CT

    SciTech Connect

    Lu Wei; Parikh, Parag J.; Hubenschmidt, James P.; Bradley, Jeffrey D.; Low, Daniel A.

    2006-08-15

    Respiratory motion can cause significant dose delivery errors in conformal radiation therapy for thoracic and upper abdominal tumors. Four-dimensional computed tomography (4D CT) has been proposed to provide the image data necessary to model tumor motion and consequently reduce these errors. The purpose of this work was to compare 4D CT reconstruction methods using amplitude sorting and phase angle sorting. A 16-slice CT scanner was operated in cine mode to acquire 25 scans consecutively at each couch position through the thorax. The patient underwent synchronized external respiratory measurements. The scans were sorted into 12 phases based, respectively, on the amplitude and direction (inhalation or exhalation) or on the phase angle (0-360 deg.) of the external respiratory signal. With the assumption that lung motion is largely proportional to the measured respiratory amplitude, the variation in amplitude corresponds to the variation in motion for each phase. A smaller variation in amplitude would associate with an improved reconstructed image. Air content, defined as the amount of air within the lungs, bronchi, and trachea in a 16-slice CT segment and used by our group as a surrogate for internal motion, was correlated to the respiratory amplitude and phase angle throughout the lungs. For the 35 patients who underwent quiet breathing, images (similar to those used for treatment planning) and animations (used to display respiratory motion) generated using amplitude sorting displayed fewer reconstruction artifacts than those generated using phase angle sorting. The variations in respiratory amplitude were significantly smaller (P<0.001) with amplitude sorting than those with phase angle sorting. The subdivision of the breathing cycle into more (finer) phases improved the consistency in respiratory amplitude for amplitude sorting, but not for phase angle sorting. For 33 of the 35 patients, the air content showed significantly improved (P<0.001) correlation with the

  3. FEV1/FEV6 to Diagnose Airflow Obstruction. Comparisons with Computed Tomography and Morbidity Indices

    PubMed Central

    Kim, Young-il; Wells, James M.; Bailey, William C.; Ramsdell, Joe W.; Foreman, Marilyn G.; Jensen, Robert L.; Stinson, Douglas S.; Wilson, Carla G.; Lynch, David A.; Make, Barry J.; Dransfield, Mark T.

    2014-01-01

    Rationale: FVC is a difficult maneuver for many patients, and forced expiratory volume in 6 seconds (FEV6) has been proposed as a surrogate for FVC for the diagnosis of chronic obstructive pulmonary disease (COPD). Previous studies have performed head-to-head comparisons of these thresholds but did not examine their relationships with structural lung disease, symptoms, or exacerbations. Objectives: To compare FEV1/FEV6 with FEV1/FVC in the diagnosis of COPD-related morbidity and structural lung disease as assessed by CT. Methods: We analyzed data from a large multicenter cohort study (COPDGene) that included current and former smokers (age 45–80 yr). Accuracy and concordance between the two ratios in diagnosing structural COPD was compared using CT measures of emphysema and airway disease and COPD-related morbidity to assess how the two ratios compare in defining disease. Results: A total of 10,018 subjects were included. FEV1/FEV6 showed excellent accuracy in diagnosing airflow obstruction using FEV1/FVC < 0.70 as a reference (area under curve, 0.99; 95% confidence interval [CI], 0.989–0.992; P < 0.001). FEV1/FEV6 < 0.73 had the best sum of sensitivity (92.1%; 95% CI, 90.8–92.4) and specificity (97.3%; 95% CI, 97.3–98.1). There was excellent agreement between the two diagnostic cutoffs (κ = 0.90; 95% CI, 0.80–0.91; P < 0.001). In comparison with control subjects and those positive by FEV1/FVC alone, subjects positive by FEV1/FEV6 alone had greater gas trapping and airway wall thickness, worse functional capacity, and a greater number of exacerbations on follow-up. These relationships held true when disease definitions were made using the lower limits of normal. Conclusions: FEV1/FEV6 can be substituted for FEV1/FVC in diagnosing airflow obstruction and may better predict COPD-related pathology and morbidity. PMID:24450777

  4. Comparison of 68Ga-HBED-CC PSMA-PET/CT and multiparametric MRI for gross tumour volume detection in patients with primary prostate cancer based on slice by slice comparison with histopathology

    PubMed Central

    Zamboglou, Constantinos; Drendel, Vanessa; Jilg, Cordula A.; Rischke, Hans C.; Beck, Teresa I.; Schultze-Seemann, Wolfgang; Krauss, Tobias; Mix, Michael; Schiller, Florian; Wetterauer, Ulrich; Werner, Martin; Langer, Mathias; Bock, Michael; Meyer, Philipp T.; Grosu, Anca L.

    2017-01-01

    Purpose: The exact detection and delineation of the intraprostatic tumour burden is crucial for treatment planning in primary prostate cancer (PCa). We compared 68Ga-HBED-CC-PSMA PET/CT with multiparametric MRI (mpMRI) for diagnosis and tumour delineation in patients with primary PCa based on slice by slice correlation with histopathological reference material. Methodology: Seven patients with histopathologically proven primary PCa underwent 68Ga-HBED-CC-PSMA PET/CT and MRI followed by radical prostatectomy. Resected prostates were scanned by ex-vivo CT in a special localizer and prepared for histopathology. Invasive PCa was delineated on a HE stained histologic tissue slide and matched to ex-vivo CT to obtain gross tumor volume (GTV-)histo. Ex-vivo CT including GTV-histo and MRI data were matched to in-vivo CT(PET). Consensus contours based on MRI (GTV-MRI), PSMA PET (GTV-PET) or the combination of both (GTV-union/-intersection) were created. In each in-vivo CT slice the prostate was separated into 4 equal segments and sensitivity and specificity for PSMA PET and mpMRI were assessed by comparison with histological reference material. Furthermore, the spatial overlap between GTV-histo and GTV-PET/-MRI and the Sørensen-Dice coefficient (DSC) were calculated. In the case of multifocal PCa (4/7 patients), SUV values (PSMA PET) and ADC-values (diffusion weighted MRI) were obtained for each lesion. Results: PSMA PET and mpMRI detected PCa in all patients. GTV-histo was detected in 225 of 340 segments (66.2%). Sensitivity and specificity for GTV-PET, GTV-MRI, GTV-union and GTV-intersection were 75% and 87%, 70% and 82%, 82% and 67%, 55% and 99%, respectively. GTV-histo had on average the highest overlap with GTV-union (57±22%), which was significantly higher than overlap with GTV-MRI (p=0.016) and GTV-PET (p=0.016), respectively. The mean DSC for GTV-union, GTV-PET and GTV-MRI was 0.51 (±0.18), 0.45 (±0.17) and 0.48 (±0.19), respectively. In every patient with

  5. Diagnostic capability of gadoxetate disodium-enhanced liver MRI for diagnosis of hepatocellular carcinoma: comparison with multi-detector CT.

    PubMed

    Toyota, Naoyuki; Nakamura, Yuko; Hieda, Masashi; Akiyama, Naoko; Terada, Hiroaki; Matsuura, Noriaki; Nishiki, Masayo; Kono, Hirotaka; Kohno, Hiroshi; Irei, Toshimitsu; Yoshikawa, Yukinobu; Kuraoka, Kazuya; Taniyama, Kiyomi; Awai, Kazuo

    2013-09-01

    The purpose of this study was to evaluate the diagnostic capability of gadoxetate disodium (Gd-EOB)-MRI for the detection of hepatocellular carcinoma (HCC) compared with multidetector CT (MDCT). Fifty patients with 57 surgically proven HCCs who underwent Gd-EOB-MRI and MDCT from March 2008 to June 2011 were evaluated. Two observers evaluated MR and CT on a lesion-by-lesion basis. We analyzed sensitivity by grading on a 5-point scale, the degree of arterial enhancement and the differences in histological grades in the diffusion-weighted images (DWI). The results showed that the sensitivity of Gd-EOB-MRI was higher than that of MDCT especially for HCCs that were 1 cm in diameter or smaller. The hepatobiliary phase was useful for the detecting of small HCC. We had few cases in which it was difficult to judge HCC in the arterial enhancement between MRI and MDCT. In the diffusion-weighted image, well differentiated HCC tended to show a low signal intensity, and poorly differentiated HCC tended to show a high signal intensity. In moderately differentiated HCC's, the mean diameter of the high signal intensity group was larger than that of the low signal intensity group (24.5 mm vs. 15.8 mm). In conclusion, Gd-EOB-MRI tended to show higher sensitivity compared to MDCT in the detection of HCC.

  6. Patient-specific models of wall stress in abdominal aortic aneurysm: a comparison between MR and CT

    NASA Astrophysics Data System (ADS)

    de Putter, Sander; Breeuwer, Marcel; van de Vosse, Frans N.; Kose, Ursula; Gerritsen, Frans A.

    2006-03-01

    Finite element method based patient-specific wall stress in abdominal aortic aneurysm (AAA) may provide a more accurate rupture risk predictor than the currently used maximum transverse diameter. In this study, we have investigated the sensitivity of the wall stress in AAA with respect to geometrical variations. We have acquired MR and CT images for four patients with AAA. Three individual users have delineated the AAA vessel wall contours on the image slices. These contours were used to generate synthetic feature images for a deformable model based segmentation method. We investigated the reproducibility and the influence of the user variability on the wall stress. For sufficiently smooth models of the AAA wall, the peak wall stress is reproducible for three out of the four AAA geometries. The 0.99 percentiles of the wall stress show excellent reproducibility for all four AAAs. The variations induced by user variability are larger than the errors caused by the segmentation variability. The influence of the user variability appears to be similar for MR and CT. We conclude that the peak wall stress in AAA is sensitive to small geometrical variations. To increase reproducibility it appears to be best not to allow too much geometrical detail in the simulations. This could be achieved either by using a sufficiently smooth geometry representation or by using a more robust statistical parameter derived from the wall stress distribution.

  7. Sci—Fri AM: Mountain — 02: A comparison of dose reduction methods on image quality for cone beam CT

    SciTech Connect

    Webb, R; Buckley, LA

    2014-08-15

    Modern radiotherapy uses highly conformai dose distributions and therefore relies on daily image guidance for accurate patient positioning. Kilovoltage cone beam CT is one technique that is routinely used for patient set-up and results in a high dose to the patient relative to planar imaging techniques. This study uses an Elekta Synergy linac equipped with XVI cone beam CT to investigate the impact of various imaging parameters on dose and image quality. Dose and image quality are assessed as functions of x-ray tube voltage, tube current and the number of projections in the scan. In each case, the dose measurements confirm that as each parameter increases the dose increases. The assessment of high contrast resolution shows little dependence on changes to the image technique. However, low contrast visibility suggests a trade off between dose and image quality. Particularly for changes in tube potential, the dose increases much faster as a function of voltage than the corresponding increase in low contrast image quality. This suggests using moderate values of the peak tube voltage (100 – 120 kVp) since higher values result in significant dose increases with little gain in image quality. Measurements also indicate that increasing tube current achieves the greatest degree of improvement in the low contrast visibility. The results of this study highlight the need to establish careful imaging protocols to limit dose to the patient and to limit changes to the imaging parameters to those cases where there is a clear clinical requirement for improved image quality.

  8. Epigenetic regulation of L1CAM in endometrial carcinoma: comparison to cancer–testis (CT-X) antigens

    PubMed Central

    2013-01-01

    Background L1CAM was originally identified as an adhesion molecule involved in neural development. In many human carcinomas L1CAM is over-expressed and is associated with a bad prognosis. We previously reported that L1CAM was absent in the vast majority of endometrioid endometrial carcinomas (ECs) (type 1) but was strongly expressed in the more aggressive serous and clear-cell ECs (termed type 2). The differential regulation of L1CAM in ECs is not well understood. Recent evidence suggests that it can be regulated by epigenetic mechanisms. Here we investigated the role of DNA-methylation of the L1CAM promoter for expression. We also studied the relationship to cancer testis (CT-X) antigens that co-localize with L1CAM on chromosome Xq28, a region that is often activated in human tumors. Methods We used EC cell lines and primary tumor tissues for our analysis. For expression analysis we employed RT-PCR and Western blotting. DNA-Methylation of the L1CAM promoter was determined after bisulfite conversation and DNA sequencing. Tumor tissues were examined by immunohistochemical (IHC) staining. Results We demonstrate that the treatment of L1CAM low/negative expressing EC cell lines with 5′-Azacytidine (5-AzaC) or knock-down of DNMT1 (DNA methyltransferase 1) as well as the HDAC (histone deacetylase) inhibitor Trichostatin A (TSA) up-regulated L1CAM at the mRNA and protein level. The L1CAM gene has two promoter regions with two distinct CpG islands. We observed that the expression of L1CAM correlated with hypermethylation in promoter 1 and 5-AzaC treatment affected the DNA-methylation pattern in this region. The CT-X antigens NY-ESO-1, MAGE-A3 and MAGE-A4 were also strongly up-regulated by 5-AzaC or knock-down of DNMT1 but did not respond to treatment with TSA. Primary EC tumor tissues showed a variable methylation pattern of the L1CAM promoter. No striking differences in promoter methylation were observed between tumor areas with L1CAM expression and those without

  9. Partition Model-Based 99mTc-MAA SPECT/CT Predictive Dosimetry Compared with 90Y TOF PET/CT Posttreatment Dosimetry in Radioembolization of Hepatocellular Carcinoma: A Quantitative Agreement Comparison.

    PubMed

    Gnesin, Silvano; Canetti, Laurent; Adib, Salim; Cherbuin, Nicolas; Silva Monteiro, Marina; Bize, Pierre; Denys, Alban; Prior, John O; Baechler, Sebastien; Boubaker, Ariane

    2016-11-01

    (90)Y-microsphere selective internal radiation therapy (SIRT) is a valuable treatment in unresectable hepatocellular carcinoma (HCC). Partition-model predictive dosimetry relies on differential tumor-to-nontumor perfusion evaluated on pretreatment (99m)Tc-macroaggregated albumin (MAA) SPECT/CT. The aim of this study was to evaluate agreement between the predictive dosimetry of (99m)Tc-MAA SPECT/CT and posttreatment dosimetry based on (90)Y time-of-flight (TOF) PET/CT.

  10. Comparison between traditional laboratory tests, permeability measurements and CT-based fluid flow modelling for cultural heritage applications.

    PubMed

    De Boever, Wesley; Bultreys, Tom; Derluyn, Hannelore; Van Hoorebeke, Luc; Cnudde, Veerle

    2016-06-01

    In this paper, we examine the possibility to use on-site permeability measurements for cultural heritage applications as an alternative for traditional laboratory tests such as determination of the capillary absorption coefficient. These on-site measurements, performed with a portable air permeameter, were correlated with the pore network properties of eight sandstones and one granular limestone that are discussed in this paper. The network properties of the 9 materials tested in this study were obtained from micro-computed tomography (μCT) and compared to measurements and calculations of permeability and the capillary absorption rate of the stones under investigation, in order to find the correlation between pore network characteristics and fluid management characteristics of these sandstones. Results show a good correlation between capillary absorption, permeability and network properties, opening the possibility of using on-site permeability measurements as a standard method in cultural heritage applications.

  11. Comparison of Two Deformable Registration Algorithms in the Presence of Radiologic Change Between Serial Lung CT Scans.

    PubMed

    Cunliffe, Alexandra R; White, Bradley; Justusson, Julia; Straus, Christopher; Malik, Renuka; Al-Hallaq, Hania A; Armato, Samuel G

    2015-12-01

    We evaluated the image registration accuracy achieved using two deformable registration algorithms when radiation-induced normal tissue changes were present between serial computed tomography (CT) scans. Two thoracic CT scans were collected for each of 24 patients who underwent radiation therapy (RT) treatment for lung cancer, eight of whom experienced radiologically evident normal tissue damage between pre- and post-RT scan acquisition. For each patient, 100 landmark point pairs were manually placed in anatomically corresponding locations between each pre- and post-RT scan. Each post-RT scan was then registered to the pre-RT scan using (1) the Plastimatch demons algorithm and (2) the Fraunhofer MEVIS algorithm. The registration accuracy for each scan pair was evaluated by comparing the distance between landmark points that were manually placed in the post-RT scans and points that were automatically mapped from pre- to post-RT scans using the displacement vector fields output by the two registration algorithms. For both algorithms, the registration accuracy was significantly decreased when normal tissue damage was present in the post-RT scan. Using the Plastimatch algorithm, registration accuracy was 2.4 mm, on average, in the absence of radiation-induced damage and 4.6 mm, on average, in the presence of damage. When the Fraunhofer MEVIS algorithm was instead used, registration errors decreased to 1.3 mm, on average, in the absence of damage and 2.5 mm, on average, when damage was present. This work demonstrated that the presence of lung tissue changes introduced following RT treatment for lung cancer can significantly decrease the registration accuracy achieved using deformable registration.

  12. Comparison of Radiological Parameters between Normal and Patellar Dislocation Groups in Korean Population: A Rotational Profile CT-Based Study

    PubMed Central

    Prakash, Jatin; Seon, Jong-Keun; Woo, Seong-Hwan; Jin, Cheng; Song, Eun-Kyoo

    2016-01-01

    Purpose Patellofemoral instability is a common cause of anterior knee pain in adolescents and young adults. Most normal and pathological values for diagnosing patellofemoral instability are based on Western literature. We conducted this radiological study to determine normal values for different patellofemoral parameters in a Korean population and to evaluate their usefulness in diagnosis. Materials and Methods We retrospectively reviewed the rotational profile computerized tomography (CT) scans of the patellar dislocation and control groups. Trochlear, patellar, rotational profile, and trochleo-patellar alignment parameters were compared between the groups. Receiver operating characteristic curves were drawn for significant parameters, and sensitivity and specificity were calculated for the cut-off values. Results There were 48 patients in the patellar dislocation group and 87 patients in the control group. In the control group and patellar dislocation group, the mean sulcus angle was 132.5° and 143.3°, respectively, trochlear depth was 6.04 mm and 3.6 mm, bisect offset was 56.4% and 99.9%, lateral patellar tilting was 9.8° and 19.2°, patellar facet asymmetry was 63.5% and 45.16%, and the tibial tuberosity-trochlear groove (TT-TG) distance was 10.91 mm and 27.16 mm, respectively. Conclusions The trochlear depth, bisect offset, patella tilting, and TT-TG distance were parameters that significantly contributed to patellar instability. Rotational profile CT can be considered a good diagnostic tool to assess all these parameters that help to identify anatomical aberration resulting in patellofemoral instability, thereby helping in formulating the most effective treatment plan. PMID:27894178

  13. SU-E-I-98: Dose Comparison for Pulmonary Embolism CT Studies: Single Energy Vs. Dual Energy

    SciTech Connect

    Mahmood, U; Erdi, Y

    2014-06-01

    Purpose: The purpose of this study was to assess and compare the size specific dose estimate (SSDE), dose length product (DLP) and noise relationship for pulmonary embolism studies evaluated by single source dual energy computed tomography (DECT) against conventional CT (CCT) studies in a busy cancer center and to determine the dose savings provided by DECT. Methods: An IRB-approved retrospective study was performed to determine the CTDIvol and DLP from a subset of patients scanned with both DECT and CCT over the past five years. We were able to identify 30 breast cancer patients (6 male, 24 female, age range 24 to 81) who had both DECT and CCT studies performed. DECT scans were performed with a GE HD 750 scanner (140/80 kVp, 480 mAs and 40 mm) and CCT scans were performed with a GE Lightspeed 16 slice scanner (120 kVp, 352 mAs, 20 mm). Image noise was measured by placing an ROI and recording the standard deviation of the mean HU along the descending aorta. Results: The average DECT patient size specific dose estimate was to be 14.2 ± 1.7 mGy as compared to 22.4 ± 2.7 mGy from CCT PE studies, which is a 37% reduction in the SSDE. The average DECT DLP was 721.8 ± 84.6 mGy-cm as compared to 981.8 ± 106.1 mGy-cm for CCT, which is a 26% decrease. Compared to CCT the image noise was found to decrease by 19% when using DECT for PE studies. Conclusion: DECT SSDE and DLP measurements indicate dose savings and image noise reduction when compared to CCT. In an environment that heavily debates CT patient doses, this study confirms the effectiveness of DECT in PE imaging.

  14. Comparison of physical quality assurance between Scanora 3D and 3D Accuitomo 80 dental CT scanners

    PubMed Central

    Ali, Ahmed S.; Fteita, Dareen; Kulmala, Jarmo

    2015-01-01

    Background The use of cone beam computed tomography (CBCT) in dentistry has proven to be useful in the diagnosis and treatment planning of several oral and maxillofacial diseases. The quality of the resulting image is dictated by many factors related to the patient, unit, and operator. Materials and methods In this work, two dental CBCT units, namely Scanora 3D and 3D Accuitomo 80, were assessed and compared in terms of quantitative effective dose delivered to specific locations in a dosimetry phantom. Resolution and contrast were evaluated in only 3D Accuitomo 80 using special quality assurance phantoms. Results Scanora 3D, with less radiation time, showed less dosing values compared to 3D Accuitomo 80 (mean 0.33 mSv, SD±0.16 vs. 0.18 mSv, SD±0.1). Using paired t-test, no significant difference was found in Accuitomo two scan sessions (p>0.05), while it was highly significant in Scanora (p>0.05). The modulation transfer function value (at 2 lp/mm), in both measurements, was found to be 4.4%. The contrast assessment of 3D Accuitomo 80 in the two measurements showed few differences, for example, the grayscale values were the same (SD=0) while the noise level was slightly different (SD=0 and 0.67, respectively). Conclusions The radiation dose values in these two CBCT units are significantly less than those encountered in systemic CT scans. However, the dose seems to be affected more by changing the field of view rather than the voltage or amperage. The low doses were at the expense of the image quality produced, which was still acceptable. Although the spatial resolution and contrast were inferior to the medical images produced in systemic CT units, the present results recommend adopting CBCTs in maxillofacial imaging because of low radiation dose and adequate image quality. PMID:26091832

  15. Size-based emphysema cluster analysis on low attenuation area in 3D volumetric CT: comparison with pulmonary functional test

    NASA Astrophysics Data System (ADS)

    Lee, Minho; Kim, Namkug; Lee, Sang Min; Seo, Joon Beom; Oh, Sang Young

    2015-03-01

    To quantify low attenuation area (LAA) of emphysematous regions according to cluster size in 3D volumetric CT data of chronic obstructive pulmonary disease (COPD) patients and to compare these indices with their pulmonary functional test (PFT). Sixty patients with COPD were scanned by a more than 16-multi detector row CT scanner (Siemens Sensation 16 and 64) within 0.75mm collimation. Based on these LAA masks, a length scale analysis to estimate each emphysema LAA's size was performed as follows. At first, Gaussian low pass filter from 30mm to 1mm kernel size with 1mm interval on the mask was performed from large to small size, iteratively. Centroid voxels resistant to the each filter were selected and dilated by the size of the kernel, which was regarded as the specific size emphysema mask. The slopes of area and number of size based LAA (slope of semi-log plot) were analyzed and compared with PFT. PFT parameters including DLco, FEV1, and FEV1/FVC were significantly (all p-value< 0.002) correlated with the slopes (r-values; -0.73, 0.54, 0.69, respectively) and EI (r-values; -0.84, -0.60, -0.68, respectively). In addition, the D independently contributed regression for FEV1 and FEV1/FVC (adjust R sq. of regression study: EI only, 0.70, 0.45; EI and D, 0.71, 0.51, respectively). By the size based LAA segmentation and analysis, we evaluated the Ds of area, number, and distribution of size based LAA, which would be independent factors for predictor of PFT parameters.

  16. Diffuse Large B-Cell Lymphoma: Prospective Multicenter Comparison of Early Interim FLT PET/CT versus FDG PET/CT with IHP, EORTC, Deauville, and PERCIST Criteria for Early Therapeutic Monitoring.

    PubMed

    Minamimoto, Ryogo; Fayad, Luis; Advani, Ranjana; Vose, Julie; Macapinlac, Homer; Meza, Jane; Hankins, Jordan; Mottaghy, Felix; Juweid, Malik; Quon, Andrew

    2016-07-01

    Purpose To compare the performance characteristics of interim fluorine 18 ((18)F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) (after two cycles of chemotherapy) by using the most prominent standardized interpretive criteria (including International Harmonization Project [IHP] criteria, European Organization for Research and Treatment of Cancer [EORTC] criteria, and PET Response Criteria in Solid Tumors (PERCIST) versus those of interim (18)F fluorothymidine (FLT) PET/CT and simple visual interpretation. Materials and Methods This HIPAA-compliant prospective study was approved by the institutional review boards, and written informed consent was obtained. Patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL) underwent both FLT and FDG PET/CT 18-24 days after two cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone or rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin. For FDG PET/CT interpretation, IHP criteria, EORTC criteria, PERCIST, Deauville criteria, standardized uptake value, total lesion glycolysis, and metabolic tumor volume were used. FLT PET/CT images were interpreted with visual assessment by two reviewers in consensus. The interim (after cycle 2) FDG and FLT PET/CT studies were then compared with the end-of-treatment FDG PET/CT studies to determine which interim examination and/or criteria best predicted the result after six cycles of chemotherapy. Results From November 2011 to May 2014, there were 60 potential patients for inclusion, of whom 46 patients (24 men [mean age, 60.9 years ± 13.7; range, 28-78 years] and 22 women [mean age, 57.2 years ± 13.4; range, 25-76 years]) fulfilled the criteria. Thirty-four patients had complete response, and 12 had residual disease at the end of treatment. FLT PET/CT had a significantly higher positive predictive value (PPV) (91%) in predicting residual disease than did any FDG PET/CT interpretation method

  17. Head CT scan

    MedlinePlus

    Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... conditions: Birth (congenital) defect of the head or brain Brain infection Brain tumor Buildup of fluid inside ...

  18. Comparison between blinded and partially blinded detection of gastric cancer with multidetector CT using surgery and endoscopic submucosal dissection as reference standards.

    PubMed

    Kim, H J; Lee, D H; Ko, Y T

    2010-08-01

    The aim of this study is to compare blinded with partially blinded detection of gastric cancer with multidetector (MD) CT by using surgery and endoscopic submucosal dissection (ESD) as reference standards. 44 patients with gastric cancer underwent MDCT with air as an oral contrast agent. Surgery was performed on 37 patients, ESD on six and surgery after ESD on one. To provide comparison cases of blinded evaluation, 38 MDCT examinations were added for cases where no focal gastric lesion was seen on endoscopy. Two radiologists, blinded to the presence, number and location of the tumours, evaluated axial and axial plus multiplanar reformation (MPR) images of 82 MDCT examinations with or without gastric cancer. For partially blinded evaluation, the same radiologists, blinded to the location and number of tumours, evaluated axial and axial plus MPR images of 44 MDCT examinations of gastric cancer. Differences in assessment were resolved by consensus. 45 gastric cancers were found in surgical and ESD specimens. Detection rates of gastric cancer from axial and axial plus MPR images during blinded evaluation and from axial and axial plus MPR images during partially blinded evaluation were 62% (28/45), 64% (29/45), 64% (29/45) and 71% (32/45), respectively. There was no statistical significance for the comparison between blinded and partially blinded detection rates of gastric cancer. The detection rate of gastric cancer with MDCT during blinded evaluation showed no specific difference compared with the detection rate of gastric cancer with MDCT during partially blinded evaluation.

  19. CT Pulmonary Angiography at Reduced Radiation Exposure and Contrast Material Volume Using Iterative Model Reconstruction and iDose4 Technique in Comparison to FBP

    PubMed Central

    Laqmani, Azien; Kurfürst, Maximillian; Butscheidt, Sebastian; Sehner, Susanne; Schmidt-Holtz, Jakob; Behzadi, Cyrus; Nagel, Hans Dieter; Adam, Gerhard; Regier, Marc

    2016-01-01

    Purpose To assess image quality of CT pulmonary angiography (CTPA) at reduced radiation exposure (RD-CTPA) and contrast medium (CM) volume using two different iterative reconstruction (IR) algorithms (iDose4 and iterative model reconstruction (IMR)) in comparison to filtered back projection (FBP). Materials and Methods 52 patients (body weight < 100 kg, mean BMI: 23.9) with suspected pulmonary embolism (PE) underwent RD-CTPA (tube voltage: 80 kV; mean CTDIvol: 1.9 mGy) using 40 ml CM. Data were reconstructed using FBP and two different IR algorithms (iDose4 and IMR). Subjective and objective image quality and conspicuity of PE were assessed in central, segmental, and subsegmental arteries. Results Noise reduction of 55% was achieved with iDose4 and of 85% with IMR compared to FBP. Contrast-to-noise ratio significantly increased with iDose4 and IMR compared to FBP (p<0.05). Subjective image quality was rated significantly higher at IMR reconstructions in comparison to iDose4 and FBP. Conspicuity of central and segmental PE significantly improved with the use of IMR. In subsegmental arteries, iDose4 was superior to IMR. Conclusions CTPA at reduced radiation exposure and contrast medium volume is feasible with the use of IMR, which provides improved image quality and conspicuity of pulmonary embolism in central and segmental arteries. PMID:27611448

  20. Automated bone removal in CT angiography: Comparison of methods based on single energy and dual energy scans

    SciTech Connect

    Straten, Marcel van; Schaap, Michiel; Dijkshoorn, Marcel L.; Greuter, Marcel J.; Lugt, Aad van der; Krestin, Gabriel P.; Niessen, Wiro J.

    2011-11-15

    Purpose: To evaluate dual energy based methods for bone removal in computed tomography angiography (CTA) images and compare these with single energy based methods that use an additional, nonenhanced, CT scan. Methods: Four different bone removal methods were applied to CT scans of an anthropomorphic thorax phantom, acquired with a second generation dual source CT scanner. The methods differed by the way information on the presence of bone was obtained (either by using an additional, nonenhanced scan or by scanning with two tube voltages at the same time) and by the way the bone was removed from the CTA images (either by masking or subtracting the bone). The phantom contained parts which mimic vessels of various diameters in direct contact with bone. Both a quantitative and qualitative analysis of image quality after bone removal was performed. Image quality was quantified by the contrast-to-noise ratio (CNR) normalized to the square root of the dose (CNRD). At locations where vessels touch bone, the quality of the bone removal and the vessel preservation were visually assessed. The dual energy based methods were assessed with and without the addition of a 0.4 mm tin filter to the high voltage x-ray tube filtration. For each bone removal method, the dose required to obtain a certain CNR after bone removal was compared with the dose of a reference scan with the same CNR but without automated bone removal. The CNRD value of the reference scan was maximized by choosing the lowest tube voltage available. Results: All methods removed the bone completely. CNRD values were higher for the masking based methods than for the subtraction based methods. Single energy based methods had a higher CNRD value than the corresponding dual energy based methods. For the subtraction based dual energy method, tin filtration improved the CNRD value with approximately 50%. For the masking based dual energy method, it was easier to differentiate between iodine and bone when tin filtration

  1. Comparison between X-rays spectra and their effective energies in small animal CT tomographic imaging and dosimetry.

    PubMed

    Hamdi, Mahdjoub; Mimi, Malika; Bentourkia, M'hamed

    2017-03-01

    Small animal CT imaging and dosimetry usually rely on X-ray radiation produced by X-ray tubes. These X-rays typically cover a large energy range. In this study, we compared poly-energetic X-ray spectra against estimated equivalent (effective) mono-energetic beams with the same number of simulated photons for small animal CT imaging and dosimetry applications. Two poly-energetic X-ray spectra were generated from a tungsten anode at 50 and 120 kVp. The corresponding effective mono-energetic beams were established as 36 keV for the 50 kVp spectrum and 49.5 keV for the 120 kVp spectrum. To assess imaging applications, we investigated the spatial resolution by a tungsten wire, and the contrast-to-noise ratio in a reference phantom and in a realistic mouse phantom. For dosimetry investigation, we calculated the absorbed dose in a segmented digital mouse atlas in the skin, fat, heart and bone tissues. Differences of 2.1 and 2.6% in spatial resolution were respectively obtained between the 50 and 120 kVp poly-energetic spectra and their respective 36 and 49.5 keV mono-energetic beams. The differences in contrast-to-noise ratio between the poly-energetic 50 kVp spectrum and its corresponding mono-energetic 36 keV beam for air, fat, brain and bone were respectively -2.9, -0.2, 11.2 and -4.8%, and similarly between the 120 kVp and its effective energy 49.5 keV: -11.3, -20.2, -4.2 and -13.5%. Concerning the absorbed dose, for the lower X-ray beam energies, 50 kVp against 36 keV, the poly-energetic radiation doses were higher than the mono-energetic doses. Instead, for the higher X-ray beam energies, 120 kVp and 49.5 keV, the absorbed dose to the bones and lungs were higher for the mono-energetic 49.5 keV. The intensity and energy of the X-ray beam spectrum have an impact on both imaging and dosimetry in small animal studies. Simulations with mono-energetic beams should take into account these differences in order to study biological effects or to be compared to

  2. Comparison of femoral neck BMD evaluation obtained using Lunar DXA and QCT with asynchronous calibration from CT colonography.

    PubMed

    Pickhardt, Perry J; Bodeen, Gabriel; Brett, Alan; Brown, J Keenan; Binkley, Neil

    2015-01-01

    For patients undergoing screening computed tomography colonography (CTC), an opportunity exists for bone mineral density (BMD) screening without additional radiation exposure using quantitative computed tomography (QCT). This study investigated the use of dual-energy X-ray absorptiometry (DXA)-equivalent QCT Computed Tomography X-Ray Absorptiometry (CTXA) analysis at the hip obtained using CTC examinations using a retrospective asynchronous calibration of patient scans. A cohort of 33 women, age 61.3 (10.6) yr (mean [standard deviation]), had routine CTC using various GE LightSpeed CT scanner models followed after 0-9 mo by a DXA hip BMD examination using a GE Lunar Prodigy machine. Areal bone mineral density (aBMD) and T-scores of the proximal femur were measured from either prone or supine CTC examinations using Mindways QCT Pro software following standard workflow except that the CT scanners were asynchronously calibrated by phantoms scanned retrospectively of the CTC examination without the subject present. CTXA and DXA aBMD were highly correlated (R2=0.907) with a linear relationship of DXA_BMD=1.297*CTXA_BMD+0.048. The standard error of estimate (SEE) on the linear fit was 0.053 g/cm2. CTXA and DXA T-scores showed a linear relationship of DXA_T-score=1.034*CTXA_T-score+0.3 and an SEE of 0.379 T-scores. CTXA and DXA aBMD and T-score measurements showed good correlation despite asynchronous scan acquisition and retrospective QCT calibration. The SEE of 0.053 g/cm2 is on par with the literature comparing Hologic and Lunar DXA devices. The observed relationship between CTXA and Lunar DXA aBMD matches predictions from published cross-calibrations relating CTXA to DXA aBMD measurement. Thus, opportunistic use of CTXA T-scores obtained at the time of CTC could enhance osteoporosis screening.

  3. Head to Head: The Role of Academic Competition in Undergraduate Anatomical Education

    ERIC Educational Resources Information Center

    Van Nuland, Sonya E.; Roach, Victoria A.; Wilson, Timothy D.; Belliveau, Daniel J.

    2015-01-01

    Competition is a key element in many educational games and is often adopted by educators in an effort to motivate and excite their students. Yet, the use of academic competition in educational institutions remains the subject of much debate. Opponents argue that academic competition causes an increase in student anxiety and divides their…

  4. A Randomized, Head-to-Head Study of Virtual Reality Exposure Therapy for Posttraumatic Stress Disorder.

    PubMed

    McLay, Robert N; Baird, Alicia; Webb-Murphy, Jennifer; Deal, William; Tran, Lily; Anson, Heather; Klam, Warren; Johnston, Scott

    2017-04-01

    Virtual reality exposure therapy (VRET) is one of the few interventions supported by randomized controlled trials for the treatment of combat-related posttraumatic stress disorder (PTSD) in active duty service members. A comparative effectiveness study was conducted to determine if virtual reality technology itself improved outcomes, or if similar results could be achieved with a control exposure therapy (CET) condition. Service members with combat-related PTSD were randomly selected to receive nine weeks of VRET or CET. Assessors, but not therapists, were blinded. PTSD symptom improvement was assessed one week and 3 months after the conclusion of treatment using the clinician-administered PTSD scale (CAPS). A small crossover component was included. Results demonstrated that PTSD symptoms improved with both treatments, but there were no statistically significant differences between groups. Dropout rates were higher in VRET. Of those who received VRET, 13/42 (31%) showed >30% improvement on the CAPS, versus 16/43 (37%) who received CET. Three months after treatment, >30% improvement was seen in 10/33 (30%) of VRET participants and 12/33 (36%) in CET. Participants who crossed over (n = 11) showed no statistically significant improvements in a second round of treatment, regardless of condition. This study supported the utility of exposure therapy for PTSD, but did not support additional benefit by the inclusion of virtual reality.

  5. Head to head: The role of academic competition in undergraduate anatomical education.

    PubMed

    Van Nuland, Sonya E; Roach, Victoria A; Wilson, Timothy D; Belliveau, Daniel J

    2015-01-01

    Competition is a key element in many educational games and is often adopted by educators in an effort to motivate and excite their students. Yet, the use of academic competition in educational institutions remains the subject of much debate. Opponents argue that academic competition causes an increase in student anxiety and divides their attention. However, if the contexts of academic competition are defined, could the inclusion of a game-like competition in a university course be a viable and beneficial method of engaging students? Students (n = 67) were recruited from an undergraduate human anatomy course at Western University. Using a crossover design, students were exposed to a competitive tournament either at the time of their first term test or second term test. The anatomical knowledge of participating students was assessed prior to the start of the study using a baseline anatomy test. Following treatment with an online competitive anatomy tournament, student's term test grades and final course grades were analyzed. Both the second term test scores (F(2,64) = 3.743, P = 0.029) and overall course grades (F(2,64) = 3.356, P = 0.041) were found to be significantly different (P < 0.05) for individuals in the competitive group when compared to their non-competing peers. As suggested by the literature where organized competition in the classroom correlates to improved academic performance, this study uncovered significant results pertaining to increased academic performance resulting from participating in tournament-based competition. In light of these positive results, further exploration of the effects of academic competition on student performance across age brackets and disciplines is warranted.

  6. Sorting out inherent features of head-to-head gene pairs by evolutionary conservation

    PubMed Central

    2010-01-01

    Background A ‘head-to-head’ (h2h) gene pair is defined as a genomic locus in which two adjacent genes are divergently transcribed from opposite strands of DNA. In our previous work, this gene organization was found to be ancient and conserved, which subjects functionally related genes to transcriptional co-regulation. However, some of the biological features of h2h pairs still need further clarification. Results In this work, we assorted human h2h pairs into four sequentially inclusive sets of gradually incremental conservation, and examined whether those previously asserted features were conserved or sharpened in the more conserved h2h pair sets in order to identify the inherent features of the h2h gene organization. The features of TSS distance, expression correlation within h2h pairs and among h2h genes, transcription factor association and functional similarities of h2h genes were examined. Our conservation-based analyses found that the bi-directional promoters of h2h gene pairs are most likely shorter than 100 bp; h2h gene pairs generally have only significant positive expression correlation but not negative correlation, and remarkably high positive expression correlations exist among h2h genes, as well as between h2h pairs observed in our previous study; h2h paired genes tend to share transcription factors. In addition, expression correlation of h2h pairs is positively related with the TF-sharing and functional coordination, while not related with TSS distance. Conclusions Our findings remove the uncertainties of h2h genes about TSS distance, expression correlation and functional coordination, which provide insights into the study on the molecular mechanisms and functional consequences of the transcriptional regulation based on this special gene organization. PMID:21172051

  7. [68Ga]Pentixafor-PET/CT for imaging of chemokine receptor CXCR4 expression in multiple myeloma - Comparison to [18F]FDG and laboratory values

    PubMed Central

    Lapa, Constantin; Schreder, Martin; Schirbel, Andreas; Samnick, Samuel; Kortüm, Klaus Martin; Herrmann, Ken; Kropf, Saskia; Einsele, Herrmann; Buck, Andreas K.; Wester, Hans-Jürgen; Knop, Stefan; Lückerath, Katharina

    2017-01-01

    Chemokine (C-X-C motif) receptor 4 (CXCR4) is a key factor for tumor growth and metastasis in several types of human cancer including multiple myeloma (MM). Proof-of-concept of CXCR4-directed radionuclide therapy in MM has recently been reported. This study assessed the diagnostic performance of the CXCR4-directed radiotracer [68Ga]Pentixafor in MM and a potential role for stratifying patients to CXCR4-directed therapies. Thirty-five patients with MM underwent [68Ga]Pentixafor-PET/CT for evaluation of eligibility for endoradiotherapy. In 19/35 cases, [18F]FDG-PET/CT for correlation was available. Scans were compared on a patient and on a lesion basis. Tracer uptake was correlated with standard clinical parameters of disease activity. [68Ga]Pentixafor-PET detected CXCR4-positive disease in 23/35 subjects (66%). CXCR4-positivity at PET was independent from myeloma subtypes, cytogenetics or any serological parameters and turned out as a negative prognostic factor. In the 19 patients in whom a comparison to [18F]FDG was available, [68Ga]Pentixafor-PET detected more lesions in 4/19 (21%) subjects, [18F]FDG proved superior in 7/19 (37%). In the remaining 8/19 (42%) patients, both tracers detected an equal number of lesions. [18F]FDG-PET positivity correlated with [68Ga]Pentixafor-PET positivity (p=0.018). [68Ga]Pentixafor-PET provides further evidence that CXCR4 expression frequently occurs in advanced multiple myeloma, representing a negative prognostic factor and a potential target for myeloma specific treatment. However, selecting patients for CXCR4 directed therapies and prognostic stratification seem to be more relevant clinical applications for this novel imaging modality, rather than diagnostic imaging of myeloma. PMID:28042328

  8. Comparison of NaF and FDG PET/CT for assessment of treatment response in castrate-resistant prostate cancers with osseous metastases

    PubMed Central

    Simoncic, Urban; Perlman, Scott; Liu, Glenn; Staab, Mary Jane; Straus, Jane; Jeraj, Robert

    2014-01-01

    Background Assessment of skeletal metastases response to therapy is highly relevant, but unresolved clinical problem. The main goal of this work was to compare pharmacodynamic responses to therapy assessed with NaF and FDG PET/CT. Materials and Methods Prostate cancer patients with known osseous metastases were treated with Zibotentan (ZD4054) and imaged with combined dynamic NaF/FDG PET/CT prior to therapy (Baseline), after 4 weeks of therapy (Week 4) and after 2 weeks of treatment break (Week 6). Kinetic analysis allowed comparison of voxel-based tracer uptake rate parameter Ki, vasculature parameters K1 (measuring perfusion/permeability) and Vb (measuring vasculature fraction in the tissue) together with standardized uptake values (SUVs). Results Correlations were high for the NaF and FDG peak uptake parameters (Ki and SUV correlations ranged from 0.57 to 0.88) and for vasculature parameters (K1 and Vb correlations ranged from 0.61 to 0.81). Correlation between the NaF and FDG Week 4 Ki responses was low (ρ=0.35, p=0.084), but higher for NaF and FDG Week 6 Ki responses (ρ=0.72, p<0.0001). Correlations for vasculature responses were always low (ρ<0.35). NaF and FDG uptakes in the osseous metastases were spatially dislocated, with overlap in the range from 0% to 80%. Conclusions These results showed that late NaF and FDG uptake responses are consistently correlated, but earlier uptake responses and all vasculature responses can be unrelated. This study also proved that FDG and NaF uptakes are spatially dislocated. Although treatment responses assessed with NaF and FDG may be correlated, using both tracers provides additional information. PMID:25128349

  9. Are CT Scans a Satisfactory Substitute for the Follow-Up of RSA Migration Studies of Uncemented Cups? A Comparison of RSA Double Examinations and CT Datasets of 46 Total Hip Arthroplasties

    PubMed Central

    Zeleznik, Michael P.; Nilsson, Kjell G.; Olivecrona, Henrik

    2017-01-01

    As part of the 14-year follow-up of a prospectively randomized radiostereometry (RSA) study on uncemented cup fixation, two pairs of stereo radiographs and a CT scan of 46 hips were compared. Tantalum beads, inserted during the primary operation, were detected in the CT volume and the stereo radiographs and used to produce datasets of 3D coordinates. The limit of agreement between the combined CT and RSA datasets was calculated in the same way as the precision of the double RSA examination. The precision of RSA corresponding to the 99% confidence interval was 1.36°, 1.36°, and 0.60° for X-, Y-, and Z-rotation and 0.40, 0.17, and 0.37 mm for X-, Y-, and Z-translation. The limit of agreement between CT and RSA was 1.51°, 2.17°, and 1.05° for rotation and 0.59, 0.56, and 0.74 mm for translation. The differences between CT and RSA are close to the described normal 99% confidence interval for precision in RSA: 0.3° to 2° for rotation and 0.15 to 0.6 mm for translation. We conclude that measurements using CT and RSA are comparable and that CT can be used for migration studies for longitudinal evaluations of patients with RSA markers. PMID:28243598

  10. Comparison of Fusion Imaging Using a Combined SPECT/CT System and Intra-arterial CT: Assessment of Drug Distribution by an Implantable Port System in Patients Undergoing Hepatic Arterial Infusion Chemotherapy

    SciTech Connect

    Ikeda, Osamu Kusunoki, Shinichiroh; Nakaura, Takeshi; Shiraishi, Shinya; Kawanaka, Kouichi; Tomiguchi, Seiji; Yamashita, Yasuyuki; Takamori, Hiroshi; Chikamoto, Akira; Kanemitsu, Keiichiro

    2006-06-15

    Hepatic arterial infusion (HAI) chemotherapy is effective for treating primary and metastatic carcinoma of the liver. We compared the perfusion patterns of HAI chemotherapy on intra-arterial port-catheter computed tomography (iapc-CT) and fused images obtained with a combined single-photon emission computed tomography/computed tomography (SPECT/CT) system. We studied 28 patients with primary or metastatic carcinoma of the liver who bore an implantable HAI port system. All underwent abdominal SPECT using Tc-99m-MAA (185 Mbq); the injection rate was 1 mL/min, identical to the chemotherapy infusion rate, and 0.5 mL/sec for iapc-CT. Delivery was through an implantable port. We compared the intrahepatic perfusion (IHP) and extrahepatic perfusion (EHP) patterns of HAI chemotherapy on iapc-CT images and fused images obtained with a combined SPECT/CT system. In 23 of 28 patients (82%), IHP patterns on iapc-CT images and fused images were identical. In 5 of the 28 patients (18%), IHP on fusion images was different from IHP on iapc-CT images. EHP was seen on fused images in 12 of the 28 patients (43%) and on iapc-CT images in 8 patients (29%). In 17 patients (61%), upper gastrointestinal endoscopy revealed gastroduodenal mucosal lesions. EHP was revealed on fused images in 10 of these patients; 9 of them manifested gastroduodenal toxicity at the time of subsequent HAI chemotherapy. Fusion imaging using the combined SPECT/CT system reflects the actual distribution of the infused anticancer agent. This information is valuable not only for monitoring adequate drug distribution but also for avoiding potential extrahepatic complications.

  11. Accuracy of Liver Fat Quantification With Advanced CT, MRI, and Ultrasound Techniques: Prospective Comparison With MR Spectroscopy

    PubMed Central

    Kramer, Harald; Pickhardt, Perry J.; Kliewer, Mark A.; Hernando, Diego; Chen, Guang-Hong; Zagzebski, James A.; Reeder, Scott B.

    2016-01-01

    OBJECTIVE The purpose of this study was to prospectively evaluate the accuracy of proton-density fat-fraction, single- and dual-energy CT (SECT and DECT), gray-scale ultrasound (US), and US shear-wave elastography (US-SWE) in the quantification of hepatic steatosis with MR spectroscopy (MRS) as the reference standard. SUBJECTS AND METHODS Fifty adults who did not have symptoms (23 men, 27 women; mean age, 57 ± 5 years; body mass index, 27 ± 5) underwent liver imaging with unenhanced SECT, DECT, gray-scale US, US-SWE, proton-density fat-fraction MRI, and MRS for this prospective trial. MRS voxels for the reference standard were colocalized with all other modalities under investigation. For SECT (120 kVp), attenuation values were recorded. For rapid-switching DECT (80/140 kVp), monochromatic images (70–140 keV) and fat density–derived material decomposition images were reconstructed. For proton-density fat fraction MRI, a quantitative chemical shift–encoded method was used. For US, echogenicity was evaluated on a qualitative 0–3 scale. Quantitative US shear-wave velocities were also recorded. Data were analyzed by linear regression for each technique compared with MRS. RESULTS There was excellent correlation between MRS and both proton-density fat-fraction MRI (r2 = 0.992; slope, 0.974; intercept, −0.943) and SECT (r2 = 0.856; slope, −0.559; intercept, 35.418). DECT fat attenuation had moderate correlation with MRS measurements (r2 = 0.423; slope, 0.034; intercept, 8.459). There was good correlation between qualitative US echogenicity and MRS measurements with a weighted kappa value of 0.82. US-SWE velocity did not have reliable correlation with MRS measurements (r2 = 0.004; slope, 0.069; intercept, 6.168). CONCLUSION Quantitative MRI proton-density fat fraction and SECT fat attenuation have excellent linear correlation with MRS measurements and can serve as accurate noninvasive biomarkers for quantifying steatosis. Material decomposition with DECT does

  12. CT-Based Evaluation of Tumor Volume After Intra-Arterial Chemotherapy of Locally Advanced Carcinoma of the Oral Cavity: Comparison with Clinical Remission Rates

    SciTech Connect

    Rohde, Stefan Turowski, Bernd; Berkefeld, Joachim; Kovacs, Adorjan F.

    2007-02-15

    Purpose. To assess the volume of locally advanced tumors of the oral cavity and the oropharynx before and after intra-arterial (i.a.) chemotherapy by means of computed tomography and to compare these data with clinically determined treatment response of the same patient population. Methods. Eighty-eight patients with histologically proven, advanced carcinoma of the oral cavity and/or the oropharynx (local tumor stages T3/4) received neoadjuvant i.a. chemotherapy with cisplatin as part of a multimodal therapeutic regimen, comprising (1) local chemotherapy, (2) surgery, and (3) combined radio-chemotherapy. Three weeks after the intervention, residual disease was evaluated radiologically by measurement of the tumor volume and clinically by inspection and palpation of the primary tumor according to WHO criteria. Results. Comparison of treatment response according to radiological and clinical criteria respectively revealed complete remission in 5% vs. 8% (p < 0.05), partial remission in 30% vs. 31%, stable disease in 61% vs. 58%, and tumor progression in 5% vs. 2%. Conclusion. Radiological volumetry and clinical evaluation found comparable response rates after local chemotherapy. However, in patients with good response after local treatment, volumetric measurement with CT may help to distinguish between partial and complete remission. Thus, radiological tumor volumetry provides precise and differentiated information about tumor response and should be used as an additional tool in treatment monitoring after local chemotherapy.

  13. Low-dose interpolated average CT for attenuation correction in cardiac PET/CT

    NASA Astrophysics Data System (ADS)

    Wu, Tung-Hsin; Zhang, Geoffrey; Wang, Shyh-Jen; Chen, Chih-Hao; Yang, Bang-Hung; Wu, Nien-Yun; Huang, Tzung-Chi

    2010-07-01

    Because of the advantages in the use of high photon flux and thus the short scan times of CT imaging, the traditional 68Ge scans for positron emission tomography (PET) image attenuation correction have been replaced by CT scans in the modern PET/CT technology. The combination of fast CT scan and slow PET scan often causes image misalignment between the PET and CT images due to respiration motion. Use of the average CT derived from cine CT images is reported to reduce such misalignment. However, the radiation dose to patients is higher with cine CT scans. This study introduces a method that uses breath-hold CT images and their interpolations to generate the average CT for PET image attenuation correction. Breath-hold CT sets are taken at end-inspiration and end-expiration. Deformable image registration is applied to generate a voxel-to-voxel motion matrix between the two CT sets. The motion is equally divided into 5 steps from inspiration to expiration and 5 steps from expiration to inspiration, generating a total of 8 phases of interpolated CT sets. An average CT image is generated from all the 10 phase CT images, including original inhale/exhale CT and 8 interpolated CT sets. Quantitative comparison shows that the reduction of image misalignment artifacts using the average CT from the interpolation technique for PET attenuation correction is at a similar level as that using cine average CT, while the dose to the patient from the CT scans is reduced significantly. The interpolated average CT method hence provides a low dose alternative to cine CT scans for PET attenuation correction.

  14. Comparison of thoracic radiographs and single breath-hold helical CT for detection of pulmonary nodules in dogs with metastatic neoplasia.

    PubMed

    Nemanic, Sarah; London, Cheryl A; Wisner, Erik R

    2006-01-01

    Imaging studies in people indicate that x-ray computed tomography (CT) is a more sensitive technique than thoracic radiography for the detection of pulmonary metastasic neoplasia. Systematic studies comparing CT and thoracic radiographic techniques in veterinary patients have not been performed. The present retrospective study was designed to directly compare the efficacy of these 2 techniques in detecting pulmonary nodules in dogs. Eighteen dogs with histologically confirmed pulmonary metastatic neoplasia had contemporaneous thoracic radiographs and pulmonary CT scans compared. Quantitative analyses included estimation of pulmonary nodule size, number, and lobar distribution on thoracic radiographs and CT images. Only 9% of CT-detected pulmonary nodules were identified on thoracic radiographs (P < .003). The lower size threshold was approximately 1 mm to detect pulmonary nodules on CT images and 7-9 mm to reliably detect nodules on radiographs (P < .0001). Additionally, pulmonary nodules were detected in a significantly greater number of lung lobes using CT as compared with thoracic radiographs (P < .0001). These data indicate that CT is significantly more sensitive than thoracic radiography for detecting soft-tissue nodules in dogs. As such, thoracic CT should be considered in any patient with neoplasia that has potential for pulmonary metastasis to more reliably stage the disease, particularly when accurate characterization of the extent and distribution of pulmonary metastatic disease affects therapeutic planning.

  15. Three-dimensional texture analysis of contrast enhanced CT images for treatment response assessment in Hodgkin lymphoma: Comparison with F-18-FDG PET

    SciTech Connect

    Knogler, Thomas; El-Rabadi, Karem; Weber, Michael; Karanikas, Georgios; Mayerhoefer, Marius E.

    2014-12-15

    Purpose: To determine the diagnostic performance of three-dimensional (3D) texture analysis (TA) of contrast-enhanced computed tomography (CE-CT) images for treatment response assessment in patients with Hodgkin lymphoma (HL), compared with F-18-fludeoxyglucose (FDG) positron emission tomography/CT. Methods: 3D TA of 48 lymph nodes in 29 patients was performed on venous-phase CE-CT images before and after chemotherapy. All lymph nodes showed pathologically elevated FDG uptake at baseline. A stepwise logistic regression with forward selection was performed to identify classic CT parameters and texture features (TF) that enable the separation of complete response (CR) and persistent disease. Results: The TF fraction of image in runs, calculated for the 45° direction, was able to correctly identify CR with an accuracy of 75%, a sensitivity of 79.3%, and a specificity of 68.4%. Classical CT features achieved an accuracy of 75%, a sensitivity of 86.2%, and a specificity of 57.9%, whereas the combination of TF and CT imaging achieved an accuracy of 83.3%, a sensitivity of 86.2%, and a specificity of 78.9%. Conclusions: 3D TA of CE-CT images is potentially useful to identify nodal residual disease in HL, with a performance comparable to that of classical CT parameters. Best results are achieved when TA and classical CT features are combined.

  16. Comparison of the effects of salmon calcitonin (sCT) and calcitonin gene-related peptide (CGRP) in a number of in vivo and in vitro tests

    SciTech Connect

    Welch, S.P.; Brase, D.; Cooper, C.; Dewey, W.L.

    1986-03-05

    sCT and CGRP have been shown previously to have multiple activities in the central nervous system (CNS). Recent work has shown that CGRP (15 ..mu..g) intraventricularly (IVT) produces a naloxone reversible 37% inhibition in the p-phenylquinone test (PPQ) accompanied by severe diarrhea. The ED50 of sCT in the PPQ test is 362 ng and this effect is not reversed totally by naloxone. The onset of CGRP is more rapid than that of sCT. sCT and CGRP (10/sup -6/M) both produce naloxone reversible inhibition of the electrically stimulated guinea pig ileum (GPI) (25% and 50% respectively). Both sCT and CGRP (10/sup -6/ M) produce contracture (15% and 40% respectively) of the non-stimulated GPI that is not blocked by atropine. Both sCT and CGRP block the naloxone-induced contracture of the morphine (MS04) dependent ilea (29% and 68% respectively). Both sCT and CGRP produce biphasic shifts in the MS04 acetylcholine dose-effect curves in the stimulated and nonstimulated GPI, respectively. Neither sCT nor CGRP (10/sup -9/ to 10/sup -4/ M) displaces /sup 3/H-naloxone binding to mouse brain membranes. Both sCT and CGRP may produce their effects by modulation of CA/sup +2/ fluxes in the CNS and GPI.

  17. Kilovoltage cone-beam CT imaging dose during breast radiotherapy: A dose comparison between a left and right breast setup

    SciTech Connect

    Quinn, Alexandra; Holloway, Lois; Begg, Jarrad; Nelson, Vinod; Metcalfe, Peter

    2014-07-01

    The purpose of this study was to investigate the delivered dose from a kilovoltage cone-beam computed tomography (kV-CBCT) acquired in breast treatment position for a left and right breast setup. The dose was measured with thermoluminescent dosimeters positioned within a female anthropomorphic phantom at organ locations. Imaging was performed on an Elekta Synergy XVI system with the phantom setup on a breast board. The image protocol involved 120 kVp, 140 mAs, and a 270° arc rotation clockwise 0° to 270° for the left breast setup and 270° to 180° for the right breast setup (maximum arc rotations possible). The dose delivered to the left breast, right breast, and heart was 5.1 mGy, 3.9 mGy, and 4.0 mGy for the left breast setup kV-CBCT, and 6.4 mGy, 6.0 mGy, and 4.8 mGy for the right breast setup kV-CBCT, respectively. The rotation arc of the kV-CBCT influenced the dose delivered, with the right breast setup kV-CBCT found to deliver a dose of up to 4 mGy or 105% higher to the treated breast′s surface in comparison with the left breast setup. This is attributed to the kV-CBCT source being more proximal to the anterior of the phantom for a right breast setup, whereas the source is more proximal to the posterior of the patient for a left-side scan.

  18. CT scanning of the breast using a conventional CT scanner.

    PubMed

    Doust, B D; Milbrath, J R; Doust, V L

    1981-09-01

    Using a conventional body CT scanner, computed tomography of the breast was performed on 32 patients known to have or suspected of having breast masses. Xeromammograms were available for comparison in all cases. All mass lesions were histologically proved. Seven patients were examined prone, 25 supine. The prone position yielded pictures that resembled craniocaudal mammograms. Breast asymmetry, skin thickening, stranding from a mass to the chest wall, calcification, and axillary lymphadenopathy could be demonstrated by means of CT. The portion of the breast adjacent to the chest wall was more readily examined by means of CT than by conventional mammography. Internal mammary nodes could not be demonstrated.

  19. An indirect comparison of HbA1c treatment effect with albiglutide and exenatide 2.0 mg QW using the Bucher method

    PubMed Central

    Martin, Alan A; Parks, Daniel

    2016-01-01

    No head-to-head comparisons exist between once-weekly (QW) glucagon-like peptide-1 receptor agonists; accordingly, this indirect comparison was conducted to evaluate the comparative efficacy of QW albiglutide vs QW exenatide. Following a systematic literature search, it was determined that HARMONY 7 and DURATION 6, Phase III trials for albiglutide and exenatide, respectively, were similar in study design and baseline characteristics and included a common comparator arm, making them suitable for an indirect comparison using the Bucher method. The primary endpoint of change from baseline in glycated hemoglobin (HbA1c) with albiglutide 50 mg QW and exenatide 2.0 mg QW was compared and tested for noninferiority. The indirect comparison showed a treatment difference of 0.0% (95% confidence interval: −0.189% to 0.189%) in mean change in HbA1c from baseline, and albiglutide 50 mg was noninferior to exenatide 2.0 mg QW at the noninferiority margin of 0.3%. In the absence of a head-to-head trial, these results can be used in pharmacoeconomic analysis and to inform health technology assessment and clinical decision making. PMID:27274297

  20. Comparison of SPECT/CT and MRI in Diagnosing Symptomatic Lesions in Ankle and Foot Pain Patients: Diagnostic Performance and Relation to Lesion Type

    PubMed Central

    Ha, Seunggyun; Hong, Sung Hwan; Paeng, Jin Chul; Lee, Dong Yeon; Cheon, Gi Jeong; Arya, Amitabh; Chung, June-Key; Lee, Dong Soo; Kang, Keon Wook

    2015-01-01

    Purpose The purpose of this study was to compare the diagnostic performance of SPECT/CT and MRI in patients with ankle and foot pain, with regard to the lesion types. Materials and Methods Fifty consecutive patients with ankle and foot pain, who underwent 99mTc-MDP SPECT/CT and MRI, were retrospectively enrolled in this study. Symptomatic lesions were determined based on clinical examination and response to treatment. On MRI and SPECT/CT, detected lesions were classified as bone, ligament/tendon, and joint lesions. Uptake on SPECT/CT was assessed using a 4-grade system. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of SPECT/CT and MRI were evaluated in all detected lesions and each lesion type. Diagnostic value of uptake grade was analyzed using receiver-operating characteristics (ROC) curve analysis, and diagnostic performance was compared using Chi-square or McNemar tests. Results In overall lesions, the sensitivity, PPV and NPV of SPECT/CT for symptomatic lesions were 93%, 56%, 91%, and they were 98%, 48%, 95% for MRI. There was no significant difference between SPECT/CT and MRI. However, the specificity of SPECT/CT was significantly higher than that of MRI (48% versus 24%, P = 0.016). Uptake grade on SPECT/CT was significantly higher in symptomatic lesions (P < 0.001), and its area under curve on ROC analysis was 0.787. In the analysis of each lesion type, the specificity of SPECT/CT was poor in joint lesions compared with other lesion types and MRI (P < 0.001, respectively). MRI exhibited lower specificity than SPECT/CT in bone lesions (P = 0.004) and ligament/tendon lesions (P < 0.001). Conclusions SPECT/CT has MRI-comparable diagnostic performance for symptomatic lesions in ankle and foot pain patients. SPECT/CT and MRI exhibit different diagnostic specificity in different lesion types. SPECT/CT may be used as a complementary imaging method to MRI for enhancing diagnostic specificity. PMID:25668182

  1. Comparison and Consensus Guidelines for Delineation of Clinical Target Volume for CT- and MR-Based Brachytherapy in Locally Advanced Cervical Cancer

    PubMed Central

    Viswanathan, Akila N.; Erickson, Beth; Gaffney, David K.; Bosch, Walter

    2014-01-01

    Purpose/Objective To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3 Tesla (3T) magnetic resonance (MR) image-based cervical-cancer brachytherapy Materials/Methods Twenty-three gynecologic radiation oncology experts contoured the same 3 cervical-cancer brachytherapy cases: one Stage IIB near-complete response (CR) case with a tandem and ovoid, one Stage IIB partial response (PR) case with ovoid with needles and one Stage IB2 CR case with a ring applicator. CT contours were completed before MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with kappa statistics as a measure of agreement between participants. The conformity index (CI) was calculated for each of the six data sets. Dice coefficients were generated to compare CT and MR contours of the same case. Results For all 3 cases, the mean tumor volume was smaller on MR than on CT (p<0.001). Kappa and CI estimates were slightly higher for CT, indicating a higher level of agreement on CT. DICE coefficients were 89% for the Stage IB2 case with a CR, 74% for the Stage IIB case with a PR, and 57% for the Stage IIB case with a CR. Conclusion When comparing MR- to CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast visible on the images at the time of brachytherapy. The largest difference at the time of brachytherapy was in the case with parametrial extension at diagnosis that had a near-complete response, due to the appearance of the parametria on CT but not on MR. Based on these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at http://www.nrgoncology.org/Resources/ContouringAtlases.aspx. PMID:25304792

  2. Comparison of cone beam CT scans with enhanced photostimulated phosphor plate images in the detection of root fracture of endodontically treated teeth

    PubMed Central

    Bechara, B; McMahan, C A; Noujeim, M; Faddoul, T; Moore, W S; Teixeira, F B; Geha, H

    2013-01-01

    Objectives: Two-dimensional intraoral radiography is the most common tool for diagnosing root fractures (RFs). Cone beam CT (CBCT) is widely used to depict RFs in endodontically treated teeth. Beam hardening and other artefacts caused by gutta percha may result in an incorrect diagnosis when using CBCT only. A comparison of two CBCT machines with photostimulated phosphor (PSP) plate images enhanced with the equalization tool was carried out to detect RFs in endodontically treated teeth. Methods: 66 roots were collected, decoronated and treated endodontically using the same technique with gutta percha. 33 of these roots were randomly selected and fractured; the 2 root fragments were glued together with 1 layer of methyl methacrylate and placed randomly in 8 prepared beef rib fragments. Large fields of view (FOVs) were acquired with one CBCT unit and small FOVs with the second CBCT unit. Periapical radiographs (using intraoral PSP plates) were also acquired. A contrast enhancement tool was used when evaluating the PSP plate images. Results: Small FOV images had significantly higher accuracy (area under the receiver operating characteristic curve) and sensitivity in detecting RFs than PSP plates and large FOV images. The specificity of the enhanced PSP images was higher than, although not significantly higher than, the small FOV images and was significantly higher than the large FOV images. Conclusions: CBCT small FOVs should be acquired for depicting RFs of endodontically treated teeth. Images obtained using PSP plates had the lowest rate of false-positive results and their use can save the patient a radiation dose. PMID:23625067

  3. Comparison of CT- and FDG-PET-defined gross tumor volume in intensity-modulated radiotherapy for head-and-neck cancer

    SciTech Connect

    Paulino, Arnold C. . E-mail: apaulino@tmh.tmc.edu; Koshy, Mary; Howell, Rebecca; Schuster, David; Davis, Lawrence W.

    2005-04-01

    Purpose: To compare the gross tumor volume (GTV) identified on CT to that obtained from fluorodeoxyglucose (FDG) positron emission tomography (PET) and determine the differences in volume and dose coverage of the PET-GTV when the CT-GTV is used for radiotherapy planning. Methods and Materials: A total of 40 patients with intact squamous cell carcinoma arising in the head-and-neck region underwent intensity-modulated radiotherapy (IMRT) at one department. All patients underwent CT simulation for treatment planning followed by PET-CT in the treatment position. CT simulation images were fused to the CT component of the PET-CT images. The GTV using the CT simulation images was contoured (CT-GTV), as was the GTV based on the PET scan (PET-GTV). The IMRT plans were obtained using the CT-GTV. Results: The PET-GTV was smaller, the same size, and larger than the CT-GTV in 30 (75%), 3 (8%), and 7 (18%) cases respectively. The median PET-GTV and CT-GTV volume was 20.3 cm{sup 3} (range, 0.2-294) and 37.2 cm{sup 3} (range, 2-456), respectively. The volume of PET-GTV receiving at least 95% of the prescribed dose was 100% in 20 (50%), 95-99% in 10 (25%), 90-94% in 3 (8%), 85-89% in 1 (3%), 80-84% in 2 (5%), 75-79% in 1 (3%), and <75% in 3 (8%) cases. The minimal dose received by 95% of the PET-GTV was {>=}100% in 19 (48%), 95-99% in 11 (28%), 90-94% in 5 (13%), 85-89% in 2 (5%), and <75% in 3 (8%) cases. Conclusion: The PET-GTV was larger than the CT-GTV in 18% of cases. In approximately 25% of patients with intact head-and-neck cancer treated using IMRT, the volume of PET-GTV receiving at least 95% of the prescribed dose and minimal dose received by 95% of the PET-GTV were less than optimal.

  4. SU-E-J-141: Comparison of Dose Calculation On Automatically Generated MRBased ED Maps and Corresponding Patient CT for Clinical Prostate EBRT Plans

    SciTech Connect

    Schadewaldt, N; Schulz, H; Helle, M; Renisch, S; Frantzen-Steneker, M; Heide, U

    2014-06-01

    Purpose: To analyze the effect of computing radiation dose on automatically generated MR-based simulated CT images compared to true patient CTs. Methods: Six prostate cancer patients received a regular planning CT for RT planning as well as a conventional 3D fast-field dual-echo scan on a Philips 3.0T Achieva, adding approximately 2 min of scan time to the clinical protocol. Simulated CTs (simCT) where synthesized by assigning known average CT values to the tissue classes air, water, fat, cortical and cancellous bone. For this, Dixon reconstruction of the nearly out-of-phase (echo 1) and in-phase images (echo 2) allowed for water and fat classification. Model based bone segmentation was performed on a combination of the DIXON images. A subsequent automatic threshold divides into cortical and cancellous bone. For validation, the simCT was registered to the true CT and clinical treatment plans were re-computed on the simCT in pinnacle{sup 3}. To differentiate effects related to the 5 tissue classes and changes in the patient anatomy not compensated by rigid registration, we also calculate the dose on a stratified CT, where HU values are sorted in to the same 5 tissue classes as the simCT. Results: Dose and volume parameters on PTV and risk organs as used for the clinical approval were compared. All deviations are below 1.1%, except the anal sphincter mean dose, which is at most 2.2%, but well below clinical acceptance threshold. Average deviations are below 0.4% for PTV and risk organs and 1.3% for the anal sphincter. The deviations of the stratifiedCT are in the same range as for the simCT. All plans would have passed clinical acceptance thresholds on the simulated CT images. Conclusion: This study demonstrated the clinical usability of MR based dose calculation with the presented Dixon acquisition and subsequent fully automatic image processing. N. Schadewaldt, H. Schulz, M. Helle and S. Renisch are employed by Phlips Technologie Innovative Techonologies, a

  5. [Potentialities of computed tomography and ultrasound in diagnosis of hormonally active adrenal diseases: results of comparison CT and US with operative adn histological data].

    PubMed

    Denisova, L B; Vorontsova, S V; Emel'ianova, L N

    2000-01-01

    The data given in the paper suggest that X-ray computed tomography (CT) is highly effective in detecting all types of hormonally active adrenal abnormalities. CT used in hormonally active adrenal diseases yielded data on major quantitative and qualitative (primarily densitometric) criteria that could be used in assessing the images of the adrenal area in these patients. Ultrasound study (USS) made at the first stage of topical diagnostic searches was of informative value in detecting adrenal tumor lesions, the technique being highly sensitive in the diagnosis of adrenal pheochromocytomas and adenocarcinomas, but less informative in the detection of hormonally active adrenocortical adenomas (aldesterone-producing ones in particular) than CT. The diagnosis of various adrenocortical hyperplasies and the differentiation of hyperplastic and tumor forms of hypercorticoidism are a prerogative of CT that substantially supplements USS findings in such cases.

  6. 18F-FDG PET/CT in suspected recurrences of epithelial malignant pleural mesothelioma in asbestos-fibers-exposed patients (comparison to standard diagnostic follow-up).

    PubMed

    Niccoli-Asabella, Artor; Notaristefano, Antonio; Rubini, Domenico; Altini, Corinna; Ferrari, Cristina; Merenda, Nunzio; Fanelli, Margherita; Rubini, Giuseppe

    2013-01-01

    This retrospective study evaluated the role of 18-fluorine-labeled 2-deoxy-2-fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with previous occupational or environmental exposure to asbestos, with histopathological diagnosis of epithelial malignant pleural mesothelioma and suspected recurrences, comparing the data from 18F-FDG PET/CT and computed tomography with contrast enhancement (CECT). 18F-FDG PET/CT has greater sensitivity than CECT in identifying local extent, lymph nodes, and metastasis. 18F-FDG PET/CT whole-body explorations are useful to monitor the follow-up and evaluate the metabolic response to chemo- and radiotherapy, modifying the scheduled treatment plan.

  7. In vivo micro-CT imaging of untreated and irradiated orthotopic glioblastoma xenografts in mice: capabilities, limitations and a comparison with bioluminescence imaging.

    PubMed

    Kirschner, Stefanie; Felix, Manuela C; Hartmann, Linda; Bierbaum, Miriam; Maros, Máté E; Kerl, Hans U; Wenz, Frederik; Glatting, Gerhard; Kramer, Martin; Giordano, Frank A; Brockmann, Marc A

    2015-04-01

    Small animal imaging is of increasing relevance in biomedical research. Studies systematically assessing the diagnostic accuracy of contrast-enhanced in vivo micro-CT of orthotopic glioma xenografts in mice do not exist. NOD/SCID/γc(-/-) mice (n = 27) underwent intracerebral implantation of 2.5 × 10(6) GFP-Luciferase-transduced U87MG cells. Mice underwent bioluminescence imaging (BLI) to detect tumor growth and afterwards repeated contrast-enhanced (300 µl Iomeprol i.v.) micro-CT imaging (80 kV, 75 µAs, 360° rotation, 1,000 projections, 33 s scan time, resolution 40 × 40 × 53 µm, 0.5 Gy/scan). Presence of tumors, tumor diameter and tumor volume in micro-CT were rated by two independent readers. Results were compared with histological analyses. Six mice with tumors confirmed by micro-CT received fractionated irradiation (3 × 5 Gy every other day) using the micro-CT (5 mm pencil beam geometry). Repeated micro-CT scans were tolerated well. Tumor engraftment rate was 74 % (n = 20). In micro-CT, mean tumor volume was 30 ± 33 mm(3), and the smallest detectable tumor measured 360 × 620 µm. The inter-rater agreement (n = 51 micro-CT scans) for the item tumor yes/no was excellent (Spearman-Rho = 0.862, p < 0.001). Sensitivity and specificity of micro-CT were 0.95 and 0.71, respectively (PPV = 0.91, NPV = 0.83). BLI on day 21 after tumor implantation had a sensitivity and specificity of 0.90 and 1.0, respectively (PPV = 1.0, NPV = 0.5). Maximum tumor diameter and volume in micro-CT and histology correlated excellently (tumor diameter: 0.929, p < 0.001; tumor volume: 0.969, p < 0.001, n = 17). Irradiated animals showed a large central tumor necrosis. Longitudinal contrast enhanced micro-CT imaging of brain tumor growth in live mice is feasible at high sensitivity levels and with excellent inter-rater agreement and allows visualization of radiation effects.

  8. CT Colonography (Virtual Colonoscopy)

    MedlinePlus

    ... Z CT Colonography Computed tomography (CT) colonography or virtual colonoscopy uses special x-ray equipment to examine ... and blood vessels. CT colonography, also known as virtual colonoscopy, uses low dose radiation CT scanning to ...

  9. TU-A-12A-02: Novel Lung Ventilation Imaging with Single Energy CT After Single Inhalation of Xenon: Comparison with SPECT Ventilation Images

    SciTech Connect

    Negahdar, M; Yamamoto, T; Shultz, D; Gable, L; Shan, X; Mittra, E; Loo, B; Maxim, P; Diehn, M

    2014-06-15

    Purpose: We propose a novel lung functional imaging method to determine the spatial distribution of xenon (Xe) gas in a single inhalation as a measure of regional ventilation. We compare Xe-CT ventilation to single-photon emission CT (SPECT) ventilation, which is the current clinical reference. Regional lung ventilation information may be useful for the diagnosis and monitoring of pulmonary diseases such as COPD, radiotherapy planning, and assessing the progression of toxicity after radiation therapy. Methods: In an IRB-approved clinical study, Xe-CT and SPECT ventilation scans were acquired for three patients including one patient with severe emphysema and two lung cancer patients treated with radiotherapy. For Xe- CT, we acquired two breath-hold single energy CT images of the entire lung with inspiration of 100% O2 and a mixture of 70% Xe and 30% O2, respectively. A video biofeedback system was used to achieve reproducible breath-holds. We used deformable image registration to align the breathhold images with each other to accurately subtract them, producing a map of the distribution of Xe as a surrogate of lung ventilation. We divided each lung into twelve parts and correlated the Hounsfield unit (HU) enhancement at each part with the SPECT ventilation count of the corresponding part of the lung. Results: The mean of the Pearson linear correlation coefficient values between the Xe-CT and ventilation SPECT count for all three patients were 0.62 (p<0.01). The Xe-CT image had a higher resolution than SPECT, and did not show central airway deposition artifacts that were present in the SPECT image. Conclusion: We developed a rapid, safe, clinically practical, and potentially widely accessible method for regional lung functional imaging. We demonstrated strong correlations between the Xe-CT ventilation image and SPECT ventilation image as the clinical reference. This ongoing study will investigate more patients to confirm this finding.

  10. Detection of ischaemic myocardial lesions with coronary CT angiography and adenosine-stress dynamic perfusion imaging using a 128-slice dual-source CT: diagnostic performance in comparison with cardiac MRI

    PubMed Central

    Kim, S M; Choi, J-H; Chang, S-A

    2013-01-01

    Objective: We assessed the diagnostic performance of adenosine-stress dynamic CT perfusion (ASDCTP) imaging and coronary CT angiography (CCTA) for the detection of ischaemic myocardial lesions using 128-slice dual-source CT compared with that of 1.5 T cardiac MRI. Methods: This prospective study included 33 patients (61±8 years, 82% male) with suspected coronary artery diseases who underwent ASDCTP imaging and adenosine-stress cardiac MRI. Two investigators independently evaluated ASDCTP images in correlation with significant coronary stenosis on CCTA using two different thresholds of 50% and 70% diameter stenosis. Hypoattenuated myocardial lesions on ASDCTP associated with significant coronary stenoses on CCTA were regarded as true perfusion defects. All estimates of diagnostic performance were calculated and compared with those of cardiac MRI. Results: With use of a threshold of 50% diameter stenosis on CCTA, the diagnostic estimates per-myocardial segment were as follows: sensitivity, 81% [95% confidence interval (CI): 70–92%]; specificity, 94% (95% CI: 92–96%); and accuracy 93% (95% CI: 91–95%). With use of a threshold of 70%, the diagnostic estimates were as follows: sensitivity, 48% (95% CI: 34–62%); specificity, 99% (95% CI: 98–100%); and accuracy, 94% (95% CI: 92–96%). Conclusion: Dynamic CTP using 128-slice dual-source CT enables the assessment of the physiological significance of coronary artery lesions with high diagnostic accuracy in patients with clinically suspected coronary artery disease. Advances in knowledge: Combined CCTA and ASDCTP yielded high accuracy in the detection of perfusion defects regardless of the threshold of significant coronary stenosis. PMID:24096592

  11. Reliability analysis of visual ranking of coronary artery calcification on low-dose CT of the thorax for lung cancer screening: comparison with ECG-gated calcium scoring CT.

    PubMed

    Kim, Yoon Kyung; Sung, Yon Mi; Cho, So Hyun; Park, Young Nam; Choi, Hye-Young

    2014-12-01

    Coronary artery calcification (CAC) is frequently detected on low-dose CT (LDCT) of the thorax. Concurrent assessment of CAC and lung cancer screening using LDCT is beneficial in terms of cost and radiation dose reduction. The aim of our study was to evaluate the reliability of visual ranking of positive CAC on LDCT compared to Agatston score (AS) on electrocardiogram (ECG)-gated calcium scoring CT. We studied 576 patients who were consecutively registered for health screening and undergoing both LDCT and ECG-gated calcium scoring CT. We excluded subjects with an AS of zero. The final study cohort included 117 patients with CAC (97 men; mean age, 53.4 ± 8.5). AS was used as the gold standard (mean score 166.0; range 0.4-3,719.3). Two board-certified radiologists and two radiology residents participated in an observer performance study. Visual ranking of CAC was performed according to four categories (1-10, 11-100, 101-400, and 401 or higher) for coronary artery disease risk stratification. Weighted kappa statistics were used to measure the degree of reliability on visual ranking of CAC on LDCT. The degree of reliability on visual ranking of CAC on LDCT compared to ECG-gated calcium scoring CT was excellent for board-certified radiologists and good for radiology residents. A high degree of association was observed with 71.6% of visual rankings in the same category as the Agatston category and 98.9% varying by no more than one category. Visual ranking of positive CAC on LDCT is reliable for predicting AS rank categorization.

  12. Airway Segmentation and Centerline Extraction from Thoracic CTComparison of a New Method to State of the Art Commercialized Methods

    PubMed Central

    Reynisson, Pall Jens; Scali, Marta; Smistad, Erik; Hofstad, Erlend Fagertun; Leira, Håkon Olav; Lindseth, Frank; Nagelhus Hernes, Toril Anita; Amundsen, Tore; Sorger, Hanne; Langø, Thomas

    2015-01-01

    airways and the centerlines. Reference segmentation comparison averages and standard deviations for MPM and TSF correspond to literature. Conclusion The TSF is able to segment the airways and extract the centerlines in one single step. The number of branches found is lower for the TSF method than in Mimics. OsiriX demands the highest number of clicks to process the data, the segmentation is often sparse and extracting the centerline requires the use of another software system. Two of the software systems performed satisfactory with respect to be used in preprocessing CT images for navigated bronchoscopy, i.e. the TSF method and the MPM. According to reference segmentation both TSF and MPM are comparable with other segmentation methods. The level of automaticity and the resulting high number of branches plus the fact that both centerline and the surface of the airways were extracted, are requirements we considered particularly important. The in house method has the advantage of being an integrated part of a navigation platform for bronchoscopy, whilst the other methods can be considered preprocessing tools to a navigation system. PMID:26657513

  13. Color duplex ultrasound and contrast-enhanced ultrasound in comparison to MS-CT in the detection of endoleak following endovascular aneurysm repair.

    PubMed

    Clevert, D-A; Minaifar, N; Weckbach, S; Kopp, R; Meimarakis, G; Clevert, D-A; Reiser, M

    2008-01-01

    The purpose of this study was to compare Color Duplex Ultrasound (CDU), Contrast-Enhanced Ultrasound (CEUS) and Multislice Computed Tomography (MS-CT) angiography in the routine follow up of patients following Endovascular Repair (EVAR) of Abdominal Aortic Aneurysm (AAA).43 consecutive patients with AAA underwent endovascular aneurysm repair and were imaged with CDU, CEUS and MS-CT angiography at regular intervals after the procedure. Each imaging modality was evaluated for the detection of endoleaks. The presence of endoleaks was analyzed and the conspicuity of findings was assessed.CTA was used as gold standard in determining the presence of endoleaks. CDU was true positive for endoleaks in 5/43 patients (11.6%) and false positive for endoleaks in 2/43 patients (4.6%). The sensitivity of CDU was therefore 33.3% and its specificity 92.8%; the positive and negative predictive values were 0.71 and 0.72, respectively. CEUS was true positive for the detection of endoleaks in 15/43 patients (34.9%) and false positive in 2/43 patients (4.6%). The sensitivity of CEUS was therefore 100% and its specificity 93%; the positive and negative predictive values were 0.88 and 1. In the follow up the two false positive endoleaks in CEUS were confirmed as true positive endoleaks by CEUS and MS-CT. In our small patient group, contrast-enhanced ultrasound seemed to be more accurately in demonstrating endoleaks after EVAR than MS-CT angiography and may be considered as a primary surveillance modality whereas duplex ultrasound scanning alone is not as sensitive as CEUS and MS-CT angiography in detection of endoleaks. Especially in patients with contraindications for CT contrast agents (e.g. due to renal failure or severe allergy) CEUS provides a good alternative to MS-CT.

  14. Anxiety in Cancer Patients during 18F-FDG PET/CT Low Dose: A Comparison of Anxiety Levels before and after Imaging Studies

    PubMed Central

    Vieira, Lina; Carolino, Elisabete; Oliveira, Cátia; Pacheco, Carolina; Castro, Maria; Alonso, Juan

    2017-01-01

    Objective. Assessing the level of anxiety in oncology patients who underwent 18F-FDG PET/CT low dose scan and identifying the main reasons that generate anxiety. Material and Method. The study included 81 cancer patients submitted to the 18F-FDG PET/CT low dose scan. Patients filled in the Scan Experience Questionnaire and the State-Trait Anxiety Inventory (STAI) before and after 18F-FDG PET/CT low dose scan. Results. Substantial levels of anxiety were detected both before and after 18F-FDG PET/CT low dose scan (STAI mean > 30), with a significant increase in the state of anxiety after scan performance (p < 0.0001, Medianpre = 31.1, and Medianpos = 33.0). 18F-FDG PET/CT low dose results are the main cause of anxiety both before (79.1%) and after (86.9%) the scan. The information provided by staff both before and on the 18F-FDG PET/CT low dose day was classified mostly as completely understandable (70.5% and 75.3%, resp.) and as very useful (70.5% and 72.6%, resp.) and correlated positively with patients' overall satisfaction with NM Department (rS = 0.372, p = 0.004 and rS = 0.528, p = 0.000, resp.), but not with anxiety levels. Conclusions. Patients perceive high levels of anxiety during the 18F-FDG PET/CT low dose scan and the concern with scan results was pointed out as the main factor for that emotional reaction. PMID:28392942

  15. SU-F-207-13: Comparison of Four Dimensional Computed Tomography (4D CT) Versus Breath Hold Images to Determine Pulmonary Nodule Elasticity

    SciTech Connect

    Negahdar, M; Loo, B; Maxim, P

    2015-06-15

    Purpose: Elasticity may distinguish malignant from benign pulmonary nodules. To compare determining of malignant pulmonary nodule (MPN) elasticity from four dimensional computed tomography (4D CT) images versus inhale/exhale breath-hold CT images. Methods: We analyzed phase 00 and 50 of 4D CT and deep inhale and natural exhale of breath-hold CT images of 30 MPN treated with stereotactic ablative radiotherapy (SABR). The radius of the smallest MPN was 0.3 cm while the biggest one was 2.1 cm. An intensity based deformable image registration (DIR) workflow was applied to the 4D CT and breath-hold images to determine the volumes of the MPNs and a 1 cm ring of surrounding lung tissue (ring) in each state. Next, an elasticity parameter was derived by calculating the ratio of the volume changes of MPN (exhale:inhale or phase50:phase00) to that of a 1 cm ring of lung tissue surrounding the MPN. The proposed formulation of elasticity enables us to compare volume changes of two different MPN in two different locations of lung. Results: The calculated volume ratio of MPNs from 4D CT (phase50:phase00) and breath-hold images (exhale:inhale) was 1.00±0.23 and 0.95±0.11, respectively. It shows the stiffness of MPN and comparably bigger volume changes of MPN in breath-hold images because of the deeper degree of inhalation. The calculated elasticity of MPNs from 4D CT and breath-hold images was 1.12±0.22 and 1.23±0.26, respectively. For five patients who have had two MPN in their lung, calculated elasticity of tumor A and tumor B follows same trend in both 4D CT and breath-hold images. Conclusion: We showed that 4D CT and breath-hold images are comparable in the ability to calculate the elasticity of MPN. This study has been supported by Department of Defense LCRP 2011 #W81XWH-12-1-0286.

  16. Contrast-Enhanced Ultrasound (CEUS) for Echographic Detection of Hepato Cellular Carcinoma in Cirrhotic Patients Previously Treated with Multiple Techniques: Comparison of Conventional US, Spiral CT and 3-Dimensional CEUS with Navigator Technique (3DNav CEUS)

    PubMed Central

    Giangregorio, Francesco

    2011-01-01

    A commercially available technique named “NAVIGATOR” (Esaote, Italy) easily enables a 3-D reconstruction of a single 2-D acquisition of Contrast Enhanced Ultrasound (CEUS) imaging of the whole liver (with a volumetric correction thanks to the electromagnetic device of NAVIGATOR). Aim of the study was to evaluate this “panoramic” technique in comparison with conventional US and spiral CT in the detection of new hepatic lesions. 144 cirrhotic patients (previously treated for hepato cellular carcinoma (HCC)) in follow-up with detection of 98 new nodules (N), 28 multinodular (Nmulti), 14 loco-regional regrowth (LR) 94 efficaciously treated without new nodules (neg) and four multinodular without new nodules, were submitted to 200 examinations with this new technique from November 2008 to November 2009. 3DNavCEUS was performed using SonoVue (Bracco), as contrast agent, and a machine (Technos MPX, Esaote). Spiral CT and 3DNav CEUS were performed in the same month during follow up. Sens.,Spec.,diagn.-Acc.,PPV and NPV were evaluated; comparison and differences between the techniques were obtained with chi-square (SPSS release-15). Final diagnosis was: 98 new lesions (N) (one to three), 28 multinodular HCC (Nmulti) and 14 loco-regional regrowth (LR); in 94 no more lesions were observed during follow-up; conventional US obtained: 58 N (+18 multinodularN and 8 LR), 40 false negative (+10 Nmulti and 6 LR) (sens:59.2, spec:100%, Diagn Accur:73.6, PPV:100; NPV:70.1); spiral CT obtained: 84N (+26-multinodularN and 14-LR), 14 false-negative (+2-Nmulti), and one false-positive (sens:85.7, spec:97.9%, Diagn Accur:90.9, PPV:97.7; NPV:86.8); 3DNAV obtained: 92N (+28 multinodularN and 14LR), 6 false-negative, and two false-positives (sens:93.9, spec:97.9%, Diagn Accur:95.6, PPV:97.9; NPV:93.9). 3-DNav CEUS is significantly better than US and almost similar to spiral CT for detection of new HCC. This technique, in particular, showed the presence of lesions even in the cases not

  17. Staging of Primary Abdominal Lymphomas: Comparison of Whole-Body MRI with Diffusion-Weighted Imaging and 18F-FDG-PET/CT

    PubMed Central

    Stecco, Alessandro; Buemi, Francesco; Quagliozzi, Martina; Lombardi, Mariangela; Santagostino, Alberto; Sacchetti, Gian Mauro; Carriero, Alessandro

    2015-01-01

    Background. The purpose of this study was to compare the accuracy of whole-body MRI with diffusion-weighted sequences (WB-DW-MRI) with that of 18F-FDG-PET/CT in the staging of patients with primary gastrointestinal lymphoma. Methods. This retrospective study involved 17 untreated patients with primary abdominal gastrointestinal lymphoma. All patients underwent 18F-FDG-PET/CT and WB-DW-MRI. Histopathology findings or at least 6 months of clinical and radiological follow-up was the gold standard. The Musshoff-modified Ann Arbor system was used for staging, and diagnostic accuracy was evaluated on a per-node basis. Results. WB-DW-MRI exhibited 100% sensitivity, 96.3% specificity, and 96.1% and 100% positive and negative predictive values (PPV and NPV), respectively. The sensitivity, specificity, and PPV and NPV of PET/CT were 95.9%, 100%, and 100% and 96.4%, respectively. There were no statistically significant differences between the two techniques (p = 0.05). The weighted kappa agreement statistics with a 95% confidence interval were 0.97 (0.95–0.99) between the two MRI readers and 0.87 (0.82–0.92) between the two methods. Conclusions. WB-DW-MRI appears to have a comparable diagnostic value to 18F-FDG-PET/CT in staging patients with gastrointestinal lymphoma. PMID:26798331

  18. Screening for coronary artery disease in respiratory patients: comparison of single- and dual-source CT in patients with a heart rate above 70 bpm.

    PubMed

    Pansini, Vittorio; Remy-Jardin, Martine; Tacelli, Nunzia; Faivre, Jean-Baptiste; Flohr, Thomas; Deken, Valérie; Duhamel, Alain; Remy, Jacques

    2008-10-01

    To evaluate the assessibility of coronary arteries in respiratory patients with high heart rates. This study was based on the comparative analysis of two paired populations of 54 patients with a heart rate >70 bpm evaluated with dual-source (group 1) and single-source (group 2) CT. The mean heart rate was 89.1 bpm in group 1 and 86.7 bpm in group 2 (P=0.26). The mean number of assessable segments per patient was significantly higher in group 1 compared to group 2 (P CT angiograms of the chest. The improvement in coronary imaging with dual-source CT suggests that high heart rates should no longer be considered as contraindications for ECG-gated CT angiograms of the chest whenever clinically relevant.

  19. Simulated lesion, human observer performance comparison between thin-section dedicated breast CT images versus computed thick-section simulated projection images of the breast.

    PubMed

    Chen, L; Boone, J M; Abbey, C K; Hargreaves, J; Bateni, C; Lindfors, K K; Yang, K; Nosratieh, A; Hernandez, A; Gazi, P

    2015-04-21

    The objective of this study was to compare the lesion detection performance of human observers between thin-section computed tomography images of the breast, with thick-section (>40 mm) simulated projection images of the breast. Three radiologists and six physicists each executed a two alterative force choice (2AFC) study involving simulated spherical lesions placed mathematically into breast images produced on a prototype dedicated breast CT scanner. The breast image data sets from 88 patients were used to create 352 pairs of image data. Spherical lesions with diameters of 1, 2, 3, 5, and 11 mm were simulated and adaptively positioned into 3D breast CT image data sets; the native thin section (0.33 mm) images were averaged to produce images with different slice thicknesses; average section thicknesses of 0.33, 0.71, 1.5 and 2.9 mm were representative of breast CT; the average 43 mm slice thickness served to simulate simulated projection images of the breast.The percent correct of the human observer's responses were evaluated in the 2AFC experiments. Radiologists lesion detection performance was significantly (p < 0.05) better in the case of thin-section images, compared to thick section images similar to mammography, for all but the 1 mm lesion diameter lesions. For example, the average of three radiologist's performance for 3 mm diameter lesions was 92% correct for thin section breast CT images while it was 67% for the simulated projection images. A gradual reduction in observer performance was observed as the section thickness increased beyond about 1 mm. While a performance difference based on breast density was seen in both breast CT and the projection image results, the average radiologist performance using breast CT images in dense breasts outperformed the performance using simulated projection images in fatty breasts for all lesion diameters except 11 mm. The average radiologist performance outperformed that of the average physicist observer, however trends

  20. Simulated lesion, human observer performance comparison between thin-section dedicated breast CT images versus computed thick-section simulated projection images of the breast

    NASA Astrophysics Data System (ADS)

    Chen, L.; Boone, J. M.; Abbey, C. K.; Hargreaves, J.; Bateni, C.; Lindfors, K. K.; Yang, K.; Nosratieh, A.; Hernandez, A.; Gazi, P.

    2015-04-01

    The objective of this study was to compare the lesion detection performance of human observers between thin-section computed tomography images of the breast, with thick-section (>40 mm) simulated projection images of the breast. Three radiologists and six physicists each executed a two alterative force choice (2AFC) study involving simulated spherical lesions placed mathematically into breast images produced on a prototype dedicated breast CT scanner. The breast image data sets from 88 patients were used to create 352 pairs of image data. Spherical lesions with diameters of 1, 2, 3, 5, and 11 mm were simulated and adaptively positioned into 3D breast CT image data sets; the native thin section (0.33 mm) images were averaged to produce images with different slice thicknesses; average section thicknesses of 0.33, 0.71, 1.5 and 2.9 mm were representative of breast CT; the average 43 mm slice thickness served to simulate simulated projection images of the breast. The percent correct of the human observer’s responses were evaluated in the 2AFC experiments. Radiologists lesion detection performance was significantly (p < 0.05) better in the case of thin-section images, compared to thick section images similar to mammography, for all but the 1 mm lesion diameter lesions. For example, the average of three radiologist’s performance for 3 mm diameter lesions was 92% correct for thin section breast CT images while it was 67% for the simulated projection images. A gradual reduction in observer performance was observed as the section thickness increased beyond about 1 mm. While a performance difference based on breast density was seen in both breast CT and the projection image results, the average radiologist performance using breast CT images in dense breasts outperformed the performance using simulated projection images in fatty breasts for all lesion diameters except 11 mm. The average radiologist performance outperformed that of the average physicist

  1. A comparison of six software packages for evaluation of solid lung nodules using semi-automated volumetry: what is the minimum increase in size to detect growth in repeated CT examinations.

    PubMed

    de Hoop, Bartjan; Gietema, Hester; van Ginneken, Bram; Zanen, Pieter; Groenewegen, Gerard; Prokop, Mathias

    2009-04-01

    We compared interexamination variability of CT lung nodule volumetry with six currently available semi-automated software packages to determine the minimum change needed to detect the growth of solid lung nodules. We had ethics committee approval. To simulate a follow-up examination with zero growth, we performed two low-dose unenhanced CT scans in 20 patients referred for pulmonary metastases. Between examinations, patients got off and on the table. Volumes of all pulmonary nodules were determined on both examinations using six nodule evaluation software packages. Variability (upper limit of the 95% confidence interval of the Bland-Altman plot) was calculated for nodules for which segmentation was visually rated as adequate. We evaluated 214 nodules (mean diameter 10.9 mm, range 3.3 mm-30.0 mm). Software packages provided adequate segmentation in 71% to 86% of nodules (p < 0.001). In case of adequate segmentation, variability in volumetry between scans ranged from 16.4% to 22.3% for the various software packages. Variability with five to six software packages was significantly less for nodules >or=8 mm in diameter (range 12.9%-17.1%) than for nodules <8 mm (range 18.5%-25.6%). Segmented volumes of each package were compared to each of the other packages. Systematic volume differences were detected in 11/15 comparisons. This hampers comparison of nodule volumes between software packages.

  2. Radiation dose reduction to the breast in thoracic CT: Comparison of bismuth shielding, organ-based tube current modulation, and use of a globally decreased tube current

    SciTech Connect

    Wang Jia; Duan Xinhui; Christner, Jodie A.; Leng Shuai; Yu Lifeng; McCollough, Cynthia H.

    2011-11-15

    Purpose: The purpose of this work was to evaluate dose performance and image quality in thoracic CT using three techniques to reduce dose to the breast: bismuth shielding, organ-based tube current modulation (TCM) and global tube current reduction. Methods: Semi-anthropomorphic thorax phantoms of four different sizes (15, 30, 35, and 40 cm lateral width) were used for dose measurement and image quality assessment. Four scans were performed on each phantom using 100 or 120 kV with a clinical CT scanner: (1) reference scan; (2) scan with bismuth breast shield of an appropriate thickness; (3) scan with organ-based TCM; and (4) scan with a global reduction in tube current chosen to match the dose reduction from bismuth shielding. Dose to the breast was measured with an ion chamber on the surface of the phantom. Image quality was evaluated by measuring the mean and standard deviation of CT numbers within the lung and heart regions. Results: Compared to the reference scan, dose to the breast region was decreased by about 21% for the 15-cm phantom with a pediatric (2-ply) shield and by about 37% for the 30, 35, and 40-cm phantoms with adult (4-ply) shields. Organ-based TCM decreased the dose by 12% for the 15-cm phantom, and 34-39% for the 30, 35, and 40-cm phantoms. Global lowering of the tube current reduced breast dose by 23% for the 15-cm phantom and 39% for the 30, 35, and 40-cm phantoms. In phantoms of all four sizes, image noise was increased in both the lung and heart regions with bismuth shielding. No significant increase in noise was observed with organ-based TCM. Decreasing tube current globally led to similar noise increases as bismuth shielding. Streak and beam hardening artifacts, and a resulting artifactual increase in CT numbers, were observed for scans with bismuth shields, but not for organ-based TCM or global tube current reduction. Conclusions: Organ-based TCM produces dose reduction to the breast similar to that achieved with bismuth shielding for

  3. MRI-based IMRT planning for MR-linac: comparison between CT- and MRI-based plans for pancreatic and prostate cancers

    NASA Astrophysics Data System (ADS)

    Prior, Phil; Chen, Xinfeng; Botros, Maikel; Paulson, Eric S.; Lawton, Colleen; Erickson, Beth; Li, X. Allen

    2016-05-01

    The treatment planning in radiation therapy (RT) can be arranged to combine benefits of computed tomography (CT) and magnetic resonance imaging (MRI) together to maintain dose calculation accuracy and improved target delineation. Our aim is study the dosimetric impact of uniform relative electron density assignment on IMRT treatment planning with additional consideration given to the effect of a 1.5 T transverse magnetic field (TMF) in MR-Linac. A series of intensity modulated RT (IMRT) plans were generated for two representative tumor sites, pancreas and prostate, using CT and MRI datasets. Representative CT-based IMRT plans were generated to assess the impact of different electron density (ED) assignment on plan quality using CT without the presence of a 1.5 T TMF. The relative ED (rED) values used were taken from the ICRU report 46. Four types of rED assignment in the organs at risk (OARs), the planning target volumes (PTV) and in the non-specified tissue (NST) were considered. Dose was recalculated (no optimization) using a Monaco 5.09.07a research planning system employing Monte Carlo calculations with an option to include TMF. To investigate the dosimetric effect of different rED assignment, the dose-volume parameters (DVPs) obtained from these specific rED plans were compared to those obtained from the original plans based on CT. Overall, we found that uniform rED assignment results in differences in DVPs within 3% for the PTV and 5% for OAR. The presence of 1.5 T TMF on IMRT DVPs resulted in differences that were generally within 3% of the Gold St for both the pancreas and prostate. The combination of uniform rED assignment and TMF produced differences in DVPs that were within 4-5% of the Gold St. Larger differences in DVPs were observed for OARs on T2-based plans. The effects of using different rED assignments and the presence of 1.5 T TMF for pancreas and prostate IMRT plans are generally within 3% and 5% of PTV and OAR Gold St values. There are

  4. MRI-based IMRT planning for MR-linac: comparison between CT- and MRI-based plans for pancreatic and prostate cancers.

    PubMed

    Prior, Phil; Chen, Xinfeng; Botros, Maikel; Paulson, Eric S; Lawton, Colleen; Erickson, Beth; Li, X Allen

    2016-05-21

    The treatment planning in radiation therapy (RT) can be arranged to combine benefits of computed tomography (CT) and magnetic resonance imaging (MRI) together to maintain dose calculation accuracy and improved target delineation. Our aim is study the dosimetric impact of uniform relative electron density assignment on IMRT treatment planning with additional consideration given to the effect of a 1.5 T transverse magnetic field (TMF) in MR-Linac. A series of intensity modulated RT (IMRT) plans were generated for two representative tumor sites, pancreas and prostate, using CT and MRI datasets. Representative CT-based IMRT plans were generated to assess the impact of different electron density (ED) assignment on plan quality using CT without the presence of a 1.5 T TMF. The relative ED (rED) values used were taken from the ICRU report 46. Four types of rED assignment in the organs at risk (OARs), the planning target volumes (PTV) and in the non-specified tissue (NST) were considered. Dose was recalculated (no optimization) using a Monaco 5.09.07a research planning system employing Monte Carlo calculations with an option to include TMF. To investigate the dosimetric effect of different rED assignment, the dose-volume parameters (DVPs) obtained from these specific rED plans were compared to those obtained from the original plans based on CT. Overall, we found that uniform rED assignment results in differences in DVPs within 3% for the PTV and 5% for OAR. The presence of 1.5 T TMF on IMRT DVPs resulted in differences that were generally within 3% of the Gold St for both the pancreas and prostate. The combination of uniform rED assignment and TMF produced differences in DVPs that were within 4-5% of the Gold St. Larger differences in DVPs were observed for OARs on T2-based plans. The effects of using different rED assignments and the presence of 1.5 T TMF for pancreas and prostate IMRT plans are generally within 3% and 5% of PTV and OAR Gold St values. There are

  5. Abdominal CT scan

    MedlinePlus

    Computed tomography scan - abdomen; CT scan - abdomen; CT abdomen and pelvis ... 2016:chap 133. Radiologyinfo.org. Computed tomography (CT) - abdomen and pelvis. Updated June 16, 2016. www.radiologyinfo. ...

  6. Computed Tomography (CT) - Spine

    MedlinePlus

    ... test used to help diagnose—or rule out—spinal column damage in injured patients. CT scanning is fast, ... CT is to detect—or to rule out—spinal column damage in patients who have been injured. CT ...

  7. Organ doses, effective doses, and risk indices in adult CT: Comparison of four types of reference phantoms across different examination protocols

    SciTech Connect

    Zhang Yakun; Li Xiang; Paul Segars, W.; Samei, Ehsan

    2012-06-15

    Purpose: Radiation exposure from computed tomography (CT) to the public has increased the concern among radiation protection professionals. Being able to accurately assess the radiation dose patients receive during CT procedures is a crucial step in the management of CT dose. Currently, various computational anthropomorphic phantoms are used to assess radiation dose by different research groups. It is desirable to better understand how the dose results are affected by different choices of phantoms. In this study, the authors assessed the uncertainties in CT dose and risk estimation associated with different types of computational phantoms for a selected group of representative CT protocols. Methods: Routinely used CT examinations were categorized into ten body and three neurological examination categories. Organ doses, effective doses, risk indices, and conversion coefficients to effective dose and risk index (k and q factors, respectively) were estimated for these examinations for a clinical CT system (LightSpeed VCT, GE Healthcare). Four methods were used, each employing a different type of reference phantoms. The first and second methods employed a Monte Carlo program previously developed and validated in our laboratory. In the first method, the reference male and female extended cardiac-torso (XCAT) phantoms were used, which were initially created from the Visible Human data and later adjusted to match organ masses defined in ICRP publication 89. In the second method, the reference male and female phantoms described in ICRP publication 110 were used, which were initially developed from tomographic data of two patients and later modified to match ICRP 89 organ masses. The third method employed a commercial dosimetry spreadsheet (ImPACT group, London, England) with its own hermaphrodite stylized phantom. In the fourth method, another widely used dosimetry spreadsheet (CT-Expo, Medizinische Hochschule, Hannover, Germany) was employed together with its associated

  8. TU-G-204-01: BEST IN PHYSICS (IMAGING): Dynamic CT Myocardial Perfusion Measurement and Its Comparison to Fractional Flow Reserve

    SciTech Connect

    Ziemer, B; Hubbard, L; Groves, E; Sadeghi, B; Javan, H; Lipinski, J; Molloi, S

    2015-06-15

    Purpose: To evaluate a first pass analysis (FPA) technique for CT perfusion measurement in a swine animal and its validation using fractional flow reserve (FFR) as a reference standard. Methods: Swine were placed under anesthesia and relevant physiologic parameters were continuously recorded. Intra-coronary adenosine was administered to induce maximum hyperemia. A pressure wire was advanced distal to the first diagonal branch of the left anterior descending (LAD) artery for FFR measurements and a balloon dilation catheter was inserted over the pressure wire into the proximal LAD to create varying levels of stenosis. Images were acquired with a 320-row wide volume CT scanner. Three main coronary perfusion beds were delineated in the myocardium using arteries extracted from CT angiography images using a minimum energy hypothesis. The integrated density in the perfusion bed was used to calculate perfusion using the FPA technique. The perfusion in the LAD bed over a range of stenosis severity was measured. The measured fractional perfusion was compared to FFR and linear regression was performed. Results: The measured fractional perfusion using the FPA technique (P-FPA) and FFR were related as P-FPA = 1.06FFR – 0.06 (r{sup 2} = 0.86). The perfusion measurements were calculated with only three to five total CT volume scans, which drastically reduces the radiation dose as compared with the existing techniques requiring 15–20 volume scans. Conclusion: The measured perfusion using the first pass analysis technique showed good correlation with FFR measurements as a reference standard. The technique for perfusion measurement can potentially make a substantial reduction in radiation dose as compared with the existing techniques.

  9. The effect of nodule segmentation on the accuracy of computerized lung nodule detection on CT scans: comparison on a data set annotated by multiple radiologists

    NASA Astrophysics Data System (ADS)

    Sahiner, Berkman; Hadjiiski, Lubomir M.; Chan, Heang-Ping; Shi, Jiazheng; Way, Ted; Cascade, Philip N.; Kazerooni, Ella A.; Zhou, Chuan; Wei, Jun

    2007-03-01

    In computerized nodule detection systems on CT scans, many features that are useful for classifying whether a nodule candidate identified by prescreening is a true positive depend on the shape of the segmented object. We designed two segmentation algorithms for detailed delineation of the boundaries for nodule candidates. The first segmentation technique was a three-dimensional (3D) region-growing (RG) method which grew the object across multiple CT sections. The second technique was based on a 3D active contour (AC) model. A training set of 94 CT scans was used for algorithm design. An independent set of 62 scans, each read by multiple radiologists, was used for testing. Thirty-three scans were collected from patient files at the University of Michigan and 29 scans by the Lung Imaging Database Consortium (LIDC). In this study, we concentrated on the detection of internal lung nodules having a size >=3 mm that were not pure ground-glass opacities. Of the lesions marked by one or multiple radiologists, 124 nodules satisfied these criteria and were considered true nodules. The performance of the detection system in the AC feature space, RG feature space, and the combined feature space were compared using free-response receiver operating curves (FROC). The FROC curve using the combined feature space was significantly higher than that using the RG feature space or the AC feature space alone (p=0.02 and 0.03, respectively). At a sensitivity of 70% for internal non-GGO nodules, the FP rates were 2.2, 2.2, and 1.5 per scan, respectively, for the RG, AC, and the combined methods. Our results indicate that the 3D AC algorithm can provide useful features to improve nodule detection on CT scans.

  10. Comparison of 18F-FDG PET/CT and DWI for detection of mediastinal nodal metastasis in non-small cell lung cancer: A meta-analysis

    PubMed Central

    Zhang, Kan; Ren, Pengwei; Jia, Zhiyun

    2017-01-01

    Background Accurate clinical staging of mediastinal lymph nodes of patients with lung cancer is important in determining therapeutic options and prognoses. We aimed to compare the diagnostic performance of diffusion-weighted magnetic resonance imaging (DWI) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in detecting mediastinal nodal metastasis of lung cancer. Methods Relevant studies were systematically searched in the MEDLINE, EMBASE, PUBMED, and Cochrane Library databases. Based on extracted data, the pooled sensitivity, specificity, positive and negative likelihood ratios (PLR and NLR) with individual 95% confidence intervals were calculated. In addition, the publication bias was assessed by Deek’s funnel plot of the asymmetry test. The potential heterogeneity was explored by threshold effect analysis and subgroup analyses. Results Forty-three studies were finally included. For PET/CT, the pooled sensitivity and specificity were 0.65 (0.63–0.67) and 0.93 (0.93–0.94), respectively. The corresponding values of DWI were 0.72 (0.68–0.76) and 0.97 (0.96–0.98), respectively. The overall PLR and NLR of DWI were 13.15 (5.98–28.89) and 0.32 (0.27–0.39), respectively. For PET/CT, the corresponding values were 8.46 (6.54–10.96) and 0.38 (0.33–0.45), respectively. The Deek’s test revealed no significant publication bias. Study design and patient enrollment were potential causes for the heterogeneity of DWI studies and the threshold was a potential source for PET/CT studies. Conclusion Both modalities are beneficial in detecting lymph nodes metastases in lung cancer without significant differences between them. DWI might be an alternative modality for evaluating nodal status of NSCLC. PMID:28253364

  11. Comparison between human and model observer performance in low-contrast detection tasks in CT images: application to images reconstructed with filtered back projection and iterative algorithms

    PubMed Central

    Calzado, A; Geleijns, J; Joemai, R M S; Veldkamp, W J H

    2014-01-01

    Objective: To compare low-contrast detectability (LCDet) performance between a model [non–pre-whitening matched filter with an eye filter (NPWE)] and human observers in CT images reconstructed with filtered back projection (FBP) and iterative [adaptive iterative dose reduction three-dimensional (AIDR 3D; Toshiba Medical Systems, Zoetermeer, Netherlands)] algorithms. Methods: Images of the Catphan® phantom (Phantom Laboratories, New York, NY) were acquired with Aquilion ONE™ 320-detector row CT (Toshiba Medical Systems, Tokyo, Japan) at five tube current levels (20–500 mA range) and reconstructed with FBP and AIDR 3D. Samples containing either low-contrast objects (diameters, 2–15 mm) or background were extracted and analysed by the NPWE model and four human observers in a two-alternative forced choice detection task study. Proportion correct (PC) values were obtained for each analysed object and used to compare human and model observer performances. An efficiency factor (η) was calculated to normalize NPWE to human results. Results: Human and NPWE model PC values (normalized by the efficiency, η = 0.44) were highly correlated for the whole dose range. The Pearson's product-moment correlation coefficients (95% confidence interval) between human and NPWE were 0.984 (0.972–0.991) for AIDR 3D and 0.984 (0.971–0.991) for FBP, respectively. Bland–Altman plots based on PC results showed excellent agreement between human and NPWE [mean absolute difference 0.5 ± 0.4%; range of differences (−4.7%, 5.6%)]. Conclusion: The NPWE model observer can predict human performance in LCDet tasks in phantom CT images reconstructed with FBP and AIDR 3D algorithms at different dose levels. Advances in knowledge: Quantitative assessment of LCDet in CT can accurately be performed using software based on a model observer. PMID:24837275

  12. Comparison of aPTT and CT Parameter of the ROTEM Test to Monitor Heparin Anti-Coagulation Effect in ICU Patients: an Observational Study.

    PubMed

    Najafi, Atabak; Nikeish, Masoomeh; Etezadi, Farhad; Pourfakhr, Pejman; Imani, Farsad; Khajavi, Mohammad Reza; Shariat Moharari, Reza

    2015-10-01

    Heparin is frequently used in different clinical settings to reduce the coagulating ability of the blood. Because of probable adverse effects owing to heparin therapy and regarding variability of patients' responses to heparin, which make it very unreliable, it seems prudent to monitor meticulously its effects on the human body. There are a lot of laboratory tests to watch its effects on the body for example; aPTT and ROTEM are the most widely used tests that are performed today. We aimed to compare the aPTT test results against changes of CT parameter of the ROTEM test due to heparin administration. This study was conducted on 45 critically ill patients who needed to receive heparin according to their clinical status. All patients received 550 to 1500 unit heparin per hour (on average 17.5 unit heparin per kilogram weight). While the patients were under infusion of heparin, two blood samples (5 ml) were taken from a newly established cubital vein, just five hours after commencement of heparin therapy. One sample was used for aPTT and the other one for ROTEM. The correlation between aPTT and the changes of CT parameter of the ROTEM with heparin dosage and infusion was the primary outcome. The correlation between heparin therapy and the changes of other parameters like MCF, CFT, and a number of platelets were the secondary outcome of the study. The only significant correlation was between changes of CT and aPTT (P=0.000). The other variables were not correlated. Changes of CT parameter of ROTEM test can be used for monitoring of reduced coagulability during heparin infusion instead of aPTT test.

  13. Patlak plot analysis CT-GFR for the determination of renal function: comparison of normal dogs with autologous kidney transplant dogs.

    PubMed

    Alexander, K; Authier, S; del Castillo, J R E; Arora, V; Qi, S; Guillot, M; Beauchamp, G; Troncy, E

    2010-01-01

    Glomerular filtration rate (GFR) can be determined using Patlak plot analysis with single-slice dynamic computed tomography (CT). Acute autologous graft failure has several causes, all of which induce a measurable decrease in glomerular filtration rate. This study demonstrated in an experimental model of canine autologous renal transplant that CT-derived renal plasma clearance was significantly lower (p = 0.002) in dogs having undergone transplant (0.077 +/- 0.058 ml min(-1) ml renal tissue(-1)) compared with control dogs (0.396 +/- 0.139 ml min(-1) ml renal tissue(-1)). A significant negative curvilinear relationship was seen between serum creatinine and total renal plasma clearance (R(2) = 0.84, p = 0.0001). Alterations in renal time attenuation curve shape in dogs having undergone transplant may have been related to increased renal vascular resistance related to tubular necrosis. CT-GFR may be a useful experimental tool in the evaluation of renal dysfunction in transplant models.

  14. Accuracy of dual-source CT to identify significant coronary artery disease in patients with uncontrolled hypertension presenting with chest pain: comparison with coronary angiography.

    PubMed

    Marwan, Mohamed; Pflederer, Tobias; Schepis, Tiziano; Seltmann, Martin; Klinghammer, Lutz; Muschiol, Gerd; Ropers, Dieter; Daniel, Werner G; Achenbach, Stephan

    2012-06-01

    It has been previously reported that the sensitivity and specificity of multislice CT for detecting significant CAD (coronary artery disease) is high. Chest pain is a common presentation in patients with uncontrolled hypertension. We investigated the sensitivity and specificity of dual-source CT to detect and rule out significant CAD in patients presenting with uncontrolled hypertension accompanied by chest pain. 260 consecutive patients presenting with acute chest pain in the context of stage 2 hypertension (systolic pressure ≥160 and/or diastolic pressure ≥100) were enrolled in the study. After admission, control of blood pressure and risk stratification, 82 patients were excluded due to renal insufficiency, prior coronary revascularisation or refused participation in the study. 90 further patients with low pre-test probability of CAD were also excluded. 88 remaining patients were subjected to CT coronary angiography using dual-source CT (Definition, Siemens Medical Solutions, Forchheim, Germany) within 24 h before invasive coronary angiography. A contrast-enhanced volume dataset was acquired (120 kV, 400 mAs/rot, collimation 2 × 64 × 0.6 mm, retrospective ECG gating). Data sets were evaluated concerning the presence or absence of significant coronary stenoses and validated against invasive coronary angiography. A significant stenosis was assumed if the diameter reduction was ≥50%. 88 patients (mean age 66 ± 11 years, mean heart rate 61 ± 9 bpm) were evaluated regarding the presence or absence of significant CAD (at least one stenosis ≥50% diameter reduction). Mean systolic blood pressure on presentation was 203 ± 20 mmHg and mean diastolic blood pressure was 103 ± 13 mmHg. On a per patient basis, the sensitivity and specificity for dual-source CT to detect significant CAD in vessels >1.5 mm diameter was 100% (36/36, 95% CI 90-100) and 90% (47/52, 95% CI 79-97), respectively with a negative predictive value (NPV) of 100% (47/47, 95% CI 92-100) and a

  15. Comparison of In-Solution Biorecognition Properties of Aptamers against Ochratoxin A

    PubMed Central

    McKeague, Maureen; Velu, Ranganathan; De Girolamo, Annalisa; Valenzano, Stefania; Pascale, Michelangelo; Smith, McKenzie; DeRosa, Maria C.

    2016-01-01

    Ochratoxin A (OTA) is a mycotoxin produced as a secondary metabolite by several species of Aspergillus and Penicillium and frequently found as a natural contaminant in a wide range of food commodities. Novel and robust biorecognition agents for detecting this molecule are required. Aptamers are artificial nucleic acid ligands able to bind with high affinity and specificity to a given target molecule. In the last few years, three separate research groups have selected aptamers for ochratoxin A. While each of these three families of aptamers have been incorporated into various methods for detecting OTA, it is unclear if each aptamer candidate is better suited for a particular application. Here, we perform the first head-to-head comparison of solution-based binding parameters for these groups of aptamers. Based on our results, we provide recommendations for the appropriate choice of aptamer for incorporation into solution-based biorecognition assays and applications. PMID:27854269

  16. Comparison of chest CT findings in nontuberculous mycobacterial diseases vs. Mycobacterium tuberculosis lung disease in HIV-negative patients with cavities

    PubMed Central

    Kim, Cherry; Park, So Hee; Oh, Sang Young; Kim, Sung-Soo; Jo, Kyung-Wook; Shim, Tae Sun

    2017-01-01

    Objectives This article focuses on the differences between CT findings of HIV-negative patients who have cavities with nontuberculous mycobacteria (NTM) disease and those with Mycobacterium tuberculosis infections (TB). Methods We retrospectively reviewed 128 NTM disease patients (79 males and 49 females) with cavities in chest CT, matched for age and gender with 128 TB patients in the same period. Sputum cultures of all patients were positive for pathogens. Two independent chest radiologists evaluated the characteristics of the largest cavity and related factors. Results Interobserver agreement was excellent (κ value, 0.853–0.938). Cavity walls in NTM disease were significantly thinner (6.9±4 mm vs 10.9±6 mm, P<0.001) and more even (the ratio of thickness, 2.6±1 vs 3.7±2, P<0.001) than those in TB. The thickening of adjacent pleura next to the cavity was also significantly thicker in NTM than TB (P<0.001). However, in the multivariate analysis, thickening of adjacent pleura was the only significant factor among the representative cavity findings (Odds ratio [OR], 6.49; P<0.001). In addition, ill-defined tree-in-bud nodules (OR, 8.82; P<0.001), number of non-cavitary nodules (≥10mm) (OR, 0.72; P = 0.003), and bronchiectasis in the RUL (OR, 5.3; P = 0.002) were significantly associated ancillary findings with NTM disease in the multivariate analysis. Conclusions The major cavities in NTM disease generally have thinner and more even walls than those in TB. When cavities are associated with adjacent pleural thickening, ill-defined satellite tree-in-bud nodules, or fewer non-cavitary nodules ≥10 mm, these CT findings are highly suggestive of NTM disease rather than TB. PMID:28346488

  17. CT-guided Native Medical Renal Biopsy: Cortical Tangential versus Non-Tangential Approaches-A Comparison of Efficacy and Safety.

    PubMed

    Liu, Bo; O'Dell, Matthew; Flores, Miguel; Limback, Joseph; Kendall, Melissa; Pepe, Julie; Burt, Jeremy R; Contreras, Francisco; Lewis, Andrew R; Ward, Thomas J

    2017-04-01

    Purpose To review a single-center experience with the cortical tangential approach during computed tomography (CT)-guided native medical renal biopsy and to evaluate its efficacy and safety compared with those of a non-cortical tangential approach. Materials and Methods This retrospective study received institutional review board approval, with a waiver of the HIPAA requirement for informed consent. The number of cores, glomeruli, and complications were reviewed in 431 CT-guided medical renal biopsies performed between July 2007 and September 2015. A biopsy followed a cortical tangential approach if the needle path was parallel to the renal cortical surface, at a depth closer to the renal capsule than the renal pelvic fat. A sample was considered adequate if the biopsy yielded at least 10 glomeruli at light microscopy, one glomerulus at immunofluorescence microscopy, and one glomerulus at electron microscopy. The χ(2) test, the t test, the Mann-Whitney test, and logistic regression modeling of sample adequacy were performed. Results One hundred fifty-six (36%) of 431 biopsies were performed with the cortical tangential approach. More cores were obtained for the cortical tangential group (2.6 vs 2.4, P = .001); biopsy needle gauge was not significantly different (P = .076). More adequate samples were obtained in the cortical tangential group (66.7% vs 49.8%, P = .001), with more glomeruli (23 vs 16, P = .014). Results were significant after controlling for needle gauge and number of cores (P = .008). The cortical tangential group had fewer complications (1.9% vs 7.3%, P = .018). Conclusion The cortical tangential approach, when applied to CT-guided native medical renal biopsies, results in higher rates of sample adequacy and lower rates of postprocedural complications. (©) RSNA, 2016.

  18. SU-E-T-86: Comparison of Two Commercially Available Programs for the Evaluation of Delivered Daily Dose Using Cone Beam CT (CBCT)

    SciTech Connect

    Tuohy, R; Bosse, C; Mavroidis, P; Shi, Z; Crownover, R; Papanikolaou, N; Stathakis, S

    2014-06-01

    Purpose: In this study, two commercially available programs were compared for the evaluation of delivered daily dose using cone beam CT (CBCT). Methods: Thirty (n=30) patients previously treated in our clinic (10 prostate, 10 SBRT lung and 10 abdomen) were used in this study. The patients' plans were optimized and calculated using the Pinnacle treatment planning system. The daily CBCT scans were imported into Velocity and RayStation along with the corresponding planning CTs, structure sets and 3D dose distributions for each patient. The organs at risk (OAR) were contoured on each CBCT by the prescribing physician and were included in the evaluation of the daily delivered dose. Each CBCT was registered to the planning CT, once with rigid registration and then again, separately, with deformable registration. After registering each CBCT, the dose distribution from the planning CT was overlaid and the dose volume histograms (DVH) for the OAR and the planning target volumes (PTV) were calculated. Results: For prostate patients, we observed daily volume changes for the OARs. The DVH analysis for those patients showed variation in the sparing of the OARs while PTV coverage remained virtually unchanged using both Velocity and RayStation systems. Similar results were observed for abdominal patients. In contrast, for SBRT lung patients, the DVH for the OARs and target were comparable to those from the initial treatment plan. Differences in organ volume and organ doses were also observed when comparing the daily fractions using deformable and rigid registrations. Conclusion: By using daily CBCT dose reconstruction, we proved PTV coverage for prostate and abdominal targets is adequate. However, there is significant dosimetric change for the OARs. For lung SBRT patients, the delivered daily dose for both PTV and OAR is comparable to the planned dose with no significant differences.

  19. Hemodynamic Changes Caused by Flow Diverters in Rabbit Aneurysm Models: Comparison of Virtual and Realistic FD Deployments Based on Micro-CT Reconstruction.

    PubMed

    Xu, Jinyu; Deng, Benqiang; Fang, Yibin; Yu, Ying; Cheng, Jiyong; Wang, Shengzhang; Wang, Kuizhong; Liu, Jian-Min; Huang, Qinghai

    2013-01-01

    Adjusting hemodynamics via flow diverter (FD) implantation is emerging as a novel method of treating cerebral aneurysms. However, most previous FD-related hemodynamic studies were based on virtual FD deployment, which may produce different hemodynamic outcomes than realistic (in vivo) FD deployment. We compared hemodynamics between virtual FD and realistic FD deployments in rabbit aneurysm models using computational fluid dynamics (CFD) simulations. FDs were implanted for aneurysms in 14 rabbits. Vascular models based on rabbit-specific angiograms were reconstructed for CFD studies. Real FD configurations were reconstructed based on micro-CT scans after sacrifice, while virtual FD configurations were constructed with SolidWorks software. Hemodynamic parameters before and after FD deployment were analyzed. According to the metal coverage (MC) of implanted FDs calculated based on micro-CT reconstruction, 14 rabbits were divided into two groups (A, MC >35%; B, MC <35%). Normalized mean wall shear stress (WSS), relative residence time (RRT), inflow velocity, and inflow volume in Group A were significantly different (P<0.05) from virtual FD deployment, but pressure was not (P>0.05). The normalized mean WSS in Group A after realistic FD implantation was significantly lower than that of Group B. All parameters in Group B exhibited no significant difference between realistic and virtual FDs. This study confirmed MC-correlated differences in hemodynamic parameters between realistic and virtual FD deployment.

  20. Retrospective review of image quality of CT in polytrauma patients: comparison of patients scanned using a scoop stretcher and without a scoop stretcher.

    PubMed

    Modi, Sachin; Gadvi, Rakesh; Yeo, David; Galea-Soler, Sandro

    2014-02-01

    Increasingly pre-hospital trauma management involves transfer of patients using a scoop stretcher; a number of computed tomography (CT) compatible scoops have recently appeared on the market. We sought to evaluate any differences in image quality in polytrauma patients scanned in a scoop stretcher. CT studies of 234 consecutive patients presenting between December 2011 and August 2012 at our regional level 1 tertiary trauma centre were retrospectively reviewed. Patients were allocated into two groups: those scanned with a scoop stretcher and without. CTs were reviewed by a consultant radiologist and two senior radiology trainees and graded separately for quality/artefact. A scale of 1-5 was employed: 1-uninterpretable, 2-borderline image quality, 3-acceptable, 4-good, 5-excellent. A total of 128 (54.7 %) patients were scanned in a scoop stretcher and 106 (45.3 %) were scanned without, 183 males and 51 females (average age, 46 (16-94) years; SD, 20). The average quality grading for the patients scanned in the scoop was 4.64 compared to 4.68 in those without the scoop. There was no significant grading difference between the groups, consultant (p = 0.096) and trainees (p = 0.782). No artefacts were attributable to the scoop stretcher 0/128 (0 %). Following our experience, the use of scoop stretchers is recommended for efficient, safe and practical management of trauma patients and in terms of imaging, with no detrimental effect on image quality.

  1. Determining in vivo sternoclavicular, acromioclavicular and glenohumeral joint centre locations from skin markers, CT-scans and intracortical pins: A comparison study.

    PubMed

    Michaud, B; Jackson, M; Arndt, A; Lundberg, A; Begon, M

    2016-03-01

    To describe shoulder motion the sternoclavicular, acromioclavicular and glenohumeral joint centres must be accurately located. Within the literature various methods to estimate joint centres of rotation location are proposed, with no agreement of the method best suited to the shoulder. The objective of this study was to determine the most reliable non-invasive method for locating joint centre locations of the shoulder complex. Functional methods using pin mounted markers were compared to anatomical methods, functional methods using skin mounted markers, imaging-based methods using CT-scan data, and regression equations. Three participants took part in the study, that involved insertion of intracortical pins into the clavicle, scapula and humerus, a CT-scan of the shoulder, and finally data collection using a motion analysis system. The various methods to estimate joint centre location did not all agree, however suggestions about the most reliable non-invasive methods could be made. For the sternoclavicular joint, the authors suggest the anatomical method using the most ventral landmark on the sternoclavicular joint, as recommended by the International Society of Biomechanics. For the acromioclavicular joint, the authors suggest the anatomical method using the landmark defined as the most dorsal point on the acromioclavicular joint, as proposed by van der Helm. For the glenohumeral joint, the simple regression equation of Rab is recommended.

  2. Comparison of internal target volumes defined on 3-dimensional, 4-dimensonal, and cone-beam CT images of non-small-cell lung cancer

    PubMed Central

    Li, Fengxiang; Li, Jianbin; Ma, Zhifang; Zhang, Yingjie; Xing, Jun; Qi, Huanpeng; Shang, Dongping

    2016-01-01

    Purpose The purpose of this study was to compare the positional and volumetric differences of internal target volumes defined on three-dimensional computed tomography (3DCT), four-dimensional CT (4DCT), and cone-beam CT (CBCT) images of non-small-cell lung cancer (NSCLC). Materials and methods Thirty-one patients with NSCLC sequentially underwent 3DCT and 4DCT simulation scans of the thorax during free breathing. The first CBCT was performed and registered to the planning CT using the bony anatomy registration during radiotherapy. The gross tumor volumes were contoured on the basis of 3DCT, maximum intensity projection (MIP) of 4DCT, and CBCT. CTV3D (clinical target volume), internal target volumes, ITVMIP and ITVCBCT, were defined with a 7 mm margin accounting for microscopic disease. ITV10 mm and ITV5 mm were defined on the basis of CTV3D: ITV10 mm with a 5 mm margin in left–right (LR), anterior–posterior (AP) directions and 10 mm in cranial–caudal (CC) direction; ITV5 mm with an isotropic internal margin (IM) of 5 mm. The differences in the position, size, Dice’s similarity coefficient (DSC) and inclusion relation of different volumes were evaluated. Results The median size ratios of ITV10 mm, ITV5 mm, and ITVMIP to ITVCBCT were 2.33, 1.88, and 1.03, respectively, for tumors in the upper lobe and 2.13, 1.76, and 1.1, respectively, for tumors in the middle-lower lobe. The median DSCs of ITV10 mm, ITV5 mm, ITVMIP, and ITVCBCT were 0.6, 0.66, and 0.83 for all patients. The median percentages of ITVCBCT not included in ITV10 mm, ITV5 mm, and ITVMIP were 0.1%, 1.63%, and 15.21%, respectively, while the median percentages of ITV10 mm, ITV5 mm, and ITVMIP not included in ITVCBCT were 57.08%, 48.89%, and 20.04%, respectively. Conclusion The use of the individual ITV derived from 4DCT merely based on bony registration in radiotherapy may result in a target miss. The ITVs derived from 3DCT with isotropic margins have a good coverage of the ITV from CBCT, but the

  3. WE-AB-303-05: Breathing Motion of Liver Segments From Fiducial Tracking During Robotic Radiosurgery and Comparison with 4D-CT-Derived Fiducial Motion

    SciTech Connect

    Sutherland, J; Pantarotto, J; Nair, V; Cook, G; Plourde, M; Vandervoort, E

    2015-06-15

    Purpose: To quantify respiratory-induced motion of liver segments using the positions of implanted fiducials during robotic radiosurgery. This study also compared fiducial motion derived from four-dimensional computed tomography (4D-CT) maximum intensity projections (MIP) with motion derived from imaging during treatment. Methods: Forty-two consecutive liver patients treated with liver ablative radiotherapy were accrued to an ethics approved retrospective study. The liver segment in which each fiducial resided was identified. Fiducial positions throughout each treatment fraction were determined using orthogonal kilovoltage images. Any data due to patient repositioning or motion was removed. Mean fiducial positions were calculated. Fiducial positions beyond two standard deviations of the mean were discarded and remaining positions were fit to a line segment using least squares minimization (LSM). For eight patients, fiducial motion was derived from 4D-CT MIPs by calculating the CT number weighted mean position of the fiducial on each slice and fitting a line segment to these points using LSM. Treatment derived fiducial trajectories were corrected for patient rotation and compared to MIP derived trajectories. Results: The mean total magnitude of fiducial motion across all liver segments in left-right, anteroposterior, and superoinferior (SI) directions were 3.0 ± 0.2 mm, 9.3 ± 0.4 mm, and 20.5 ± 0.5 mm, respectively. Differences in per-segment mean fiducial motion were found with SI motion ranging from 12.6 ± 0.8 mm to 22.6 ± 0.9 mm for segments 3 and 8, respectively. Large, varied differences between treatment and MIP derived motion at simulation were found with the mean difference for SI motion being 2.6 mm (10.8 mm standard deviation). Conclusion: The magnitude of liver fiducial motion was found to differ by liver segment. MIP derived liver fiducial motion differed from motion observed during treatment, implying that 4D-CTs may not accurately capture the

  4. Benchmarking a novel ultrasound-CT fusion system for respiratory motion management in radiotherapy: assessment of spatio-temporal characteristics and comparison to 4DCT.

    PubMed

    Molloy, J A; Oldham, S A

    2008-01-01

    Management of respiratory motion during radiation therapy requires treatment planning and simulation using imaging modalities that possess sufficient spatio-temporal accuracy and precision. An investigation into the use of a novel ultrasound (US) imaging system for assessment of respiratory motion is presented, exploiting its good soft tissue contrast and temporal precision. The system dynamically superimposes the appropriate image plane sampled from a reference CT data set with the corresponding US B-mode image. An articulating arm is used for spatial registration. While the focus of the study was to quantify the system's ability to track respiratory motion, certain unique spatial calibration procedures were devised that render the software potentially valuable to the general research community. These include direct access to all transformation matrix elements and image scaling factors, a manual latency correction function, and a three-point spatial registration procedure that allows the system to be used in any room possessing a traditional radiotherapy laser localization system. Counter-intuitively, it was discovered that a manual procedure for calibrating certain transformation matrix elements produced superior accuracy to that of an algorithmic Levenberg-Marquardt optimization method. The absolute spatial accuracy was verified by comparing the physical locations of phantom test objects measured using the spatially registered US system, and using data from a 3DCT scan of the phantom as a reference. The spatial accuracy of the display superposition was also tested in a similar manner. The system's dynamic properties were then assessed using three methods. First, the overall system response time was studied using a programmable motion phantom. This included US video update, articulating arm update, CT data set resampling, and image display. The next investigation verified the system's ability to measure the range of motion of a moving anatomical test phantom that

  5. Comparison of the effect of simple and complex acquisition trajectories on the 2D SPR and 3D voxelized differences for dedicated breast CT imaging

    NASA Astrophysics Data System (ADS)

    Shah, Jainil P.; Mann, Steve D.; McKinley, Randolph L.; Tornai, Martin P.

    2014-03-01

    The 2D scatter-to-primary (SPR) ratios and 3D voxelized difference volumes were characterized for a cone beam breast CT scanner capable of arbitrary (non-traditional) 3D trajectories. The CT system uses a 30x30cm2 flat panel imager with 197 micron pixellation and a rotating tungsten anode x-ray source with 0.3mm focal spot, with an SID of 70cm. Data were acquired for two cylindrical phantoms (12.5cm and 15cm diameter) filled with three different combinations of water and methanol yielding a range of uniform densities. Projections were acquired with two acquisition trajectories: 1) simple-circular azimuthal orbit with fixed tilt; and 2) saddle orbit following a +/-15° sinusoidal trajectory around the object. Projection data were acquired in 2x2 binned mode. Projections were scatter corrected using a beam stop array method, and the 2D SPR was measured on the projections. The scatter corrected and uncorrected data were then reconstructed individually using an iterative ordered subsets convex algorithm, and the 3D difference volumes were calculated as the absolute difference between the two. Results indicate that the 2D SPR is ~7-15% higher on projections with greatest tilt for the saddle orbit, due to the longer x-ray path length through the volume, compared to the 0° tilt projections. Additionally, the 2D SPR increases with object diameter as well as density. The 3D voxelized difference volumes are an estimate of the scatter contribution to the reconstructed attenuation coefficients on a voxel level. They help visualize minor deficiencies and artifacts in the volumes due to correction methods.

  6. Head-to-Head Evaluation of the Pro-Cite and Sci-Mate Bibliographic Database Management Systems.

    ERIC Educational Resources Information Center

    Saari, David S.; Foster, George A., Jr.

    1989-01-01

    Compares two full featured database management systems for bibliographic information in terms of programs and documentation; record creation and editing; online database citations; search procedures; access to references in external text files; sorting and printing functions; style sheets; indexes; and file operations. (four references) (CLB)

  7. Comparison between CT-based volumetric calculations and ICRU reference-point estimates of radiation doses delivered to bladder and rectum during intracavitary radiotherapy for cervical cancer

    SciTech Connect

    Pelloski, Christopher E.; Palmer, Matthew B.S.; Chronowski, Gregory M.; Jhingran, Anuja; Horton, John; Eifel, Patricia J. . E-mail: peifel@mdanderson.org

    2005-05-01

    Purpose: To compare CT-based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the bladder and rectum in patients with carcinoma of the uterine cervix treated with definitive low-dose-rate intracavitary radiotherapy (ICRT). Methods and Materials: Between November 2001 and March 2003, 60 patients were prospectively enrolled in a pilot study of ICRT with CT-based dosimetry. Most patients underwent two ICRT insertions. After insertion of an afterloading ICRT applicator, intraoperative orthogonal films were obtained to ensure proper positioning of the system and to facilitate subsequent planning. Treatments were prescribed using standard two-dimensional dosimetry and planning. Patients also underwent helical CT of the pelvis for three-dimensional reconstruction of the radiation dose distributions. The systems were loaded with {sup 137}Cs sources using the Selectron remote afterloading system according to institutional practice for low-dose-rate brachytherapy. Three-dimensional dose distributions were generated using the Varian BrachyVision treatment planning system. The rectum was contoured from the bottom of the ischial tuberosities to the sigmoid flexure. The entire bladder was contoured. The minimal doses delivered to the 2 cm{sup 3} of bladder and rectum receiving the highest dose (D{sub BV2} and D{sub RV2}, respectively) were determined from dose-volume histograms, and these estimates were compared with two-dimensionally derived estimates of the doses to the corresponding ICRU reference points. Results: A total of 118 unique intracavitary insertions were performed, and 93 were evaluated and the subject of this analysis. For the rectum, the estimated doses to the ICRU reference point did not differ significantly from the D{sub RV2} (p = 0.561); the mean ({+-} standard deviation) difference was 21 cGy ({+-} 344 cGy). The median volume of the rectum that received at least

  8. Prospectively versus Retrospectively ECG-Gated 256-Slice CT Angiography to Assess Coronary Artery Bypass Grafts — Comparison of Image Quality and Radiation Dose

    PubMed Central

    Lee, Yi-Wei; Yang, Ching-Ching; Mok, Greta S. P.; Law, Wei-Yip; Su, Cheng-Tau; Wu, Tung-Hsin

    2012-01-01

    Objective In this retrospective non-randomized cohort study, the image quality and radiation dose were compared between prospectively electrocardiogram (ECG)-gated axial (PGA) and retrospectively ECG-gated helical (RGH) techniques for the assessment of coronary artery bypass grafts using 256-slice CT. Methods We studied 124 grafts with 577 segments in 64 patients with a heart rate (HR) <85 bpm who underwent CT coronary angiography (CTCA); 34 patients with RGH-CTCA and 30 patients with PGA-CTCA. The image quality of the bypass grafts was assessed by a 5-point scale (1 = excellent to 5 = non-diagnostic) for each segment (proximal anastomosis, proximal, middle, distal course of graft body, and distal anastomosis). Other objective image quality indices such as noise, signal-to-noise ratio (SNR) and contrast-to-noise ratios (CNR) were assessed. Radiation doses were also compared. Results Patient characteristics of the two groups were well matched except HR. The HR of the PGA group was lower than that of the RGH group (62.0±5.0 vs. 65.7±7.4). For both groups, over 90% of segments received excellent or good image quality scores and none was non-evaluative. The image quality generally degraded as graft segment approached to distal anastomosis regardless of techniques and graft types. Image quality scores of the PGA group were better than those of the RGH group (1.51±0.53 vs. 1.73±0.62; p<0.001). There was no significantly difference of objective image quality between two techniques, and the effective radiation dose was significantly lower in the PGA group (7.0±1.2 mSv) than that of the RGH group (20.0±4.6 mSv) (p<0.001), with a 65.0% dose reduction. Conclusions Following bypass surgery, 256-slice PGA-CTCA is superior to RGH-CTCA in limiting the radiation dose and obtaining better image quality for bypass grafts. PMID:23145126

  9. Comparison between real-time intra-operative ultrasound-based dosimetry and CT-based dosimetry for prostate brachytherapy using cesium-131.

    PubMed

    Jacobs, B L; Gibbons, E P; Smith, R P; Beriwal, S; Komanduri, K; Benoit, R M

    2008-12-01

    The purpose of this study was to evaluate the correlation between real-time intra-operative ultrasound-based dosimetry (USD) and day 0 post-implant CT dosimetry (CTD) (131)Cs permanent prostate brachytherapy. Fifty-two consecutive patients who underwent prostate brachytherapy with (131)Cs were evaluated. Real time operating room planning was performed using VariSeed 7.1 software. Post-needle placement prostate volume was used for real-time planning. Targets for dosimetry were D(90) >110%, V(100) >90%, V(150) <50%, and V(200) <20%. The CT scan for post-operative dosimetry was obtained on day 0. The mean values for USD, CTD, and the linear correlation, respectively, were, for D(90): 114.0%, 105.61%, and 0.15; for V(100): 95.1%, 91.6%, and 0.22; for V(150): 51.5%, 46.4%, and 0.40; and for V(200): 15.8%, 17.9%, and 0.42. The differences between the mean values for USD and CTD for D(90) (p<0.01), V(100) (p<0.01), and V(150) (p<0.05) were statistically significant. For D(90), 30.8% of patients had a >15% difference between USD and CTD and 51.9% of patients had a >10% difference between these values. In contrast, the USD and CTD for V(100) were within 5% in 55.8% of patients and within 10% in 86.5% of patients. This study demonstrates a correlation between the mean intra-operative USD and post-implant day 0 CTD values only for V(200). Significant variation in D(90), V(150), and V(200) values existed for individual patients between USD and CTD. These results suggest that real-time intra-operative USD does not serve as a surrogate for post-operative CTD, and that post-operative CTD is still necessary.

  10. Factors affecting uncertainty in lung nodule volume estimation with CT: comparisons of findings from two estimation methods in a phantom study

    NASA Astrophysics Data System (ADS)

    Li, Qin; Gavrielides, Marios A.; Zeng, Rongping; Myers, Kyle J.; Sahiner, Berkman; Petrick, Nicholas

    2015-03-01

    This work aimed to compare two different types of volume estimation methods (a model-based and a segmentationbased method) in terms of identifying factors affecting measurement uncertainty. Twenty-nine synthetic nodules with varying size, radiodensity, and shape were placed in an anthropomorphic thoracic phantom and scanned with a 16- detector row CT scanner. Ten repeat scans were acquired using three exposures and two slice collimations, and were reconstructed with varying slice thicknesses. Nodule volumes were estimated from the reconstructed data using a matched-filter and a segmentation approach. Log transformed volumes were used to obtain measurement error with truth obtained through micro-CT. ANOVA and multiple linear regression were applied to measurement error to identify significant factors affecting volume estimation for each method. Root mean square of measurement errors (RMSE) for meaningful subgroups, repeatability coefficients (RC) for different imaging protocols, and reproducibility coefficients (RDC) for thin and thick collimation conditions were evaluated. Results showed that for both methods, nodule size, shape and slice thickness were significant factors. Collimation was significant for the matched-filter method. RMSEs for matched-filter measurements were in general smaller than segmentation. To achieve RMSE on the order of 15% or less for {5, 8, 9, 10mm} nodules, the corresponding maximum allowable slice thicknesses were {3, 5, 5, 5mm} for the matched-filter and {0.8, 3, 3, 3mm} for the segmentation method. RCs showed similar patterns for both methods, increasing with slice thickness. For 8-10mm nodules, the measurements were highly repeatable provided the slice thickness was ≤3mm, regardless of method and across varying acquisition conditions. RDCs were lower for thin collimation than thick collimation protocols. While RDC of matched filter volume estimation results was always lower than segmentation results, for 8-10mm nodules with thin

  11. Comparison on Response and Dissolution Rates Between Ursodeoxycholic Acid Alone or in Combination With Chenodeoxycholic Acid for Gallstone Dissolution According to Stone Density on CT Scan

    PubMed Central

    Lee, Jae Min; Hyun, Jong Jin; Choi, In Young; Yeom, Suk Keu; Kim, Seung Young; Jung, Sung Woo; Jung, Young Kul; Koo, Ja Seol; Yim, Hyung Joon; Lee, Hong Sik; Lee, Sang Woo; Kim, Chang Duck

    2015-01-01

    Abstract Medical dissolution of gallstone is usually performed on radiolucent gallstones in a functioning gallbladder. However, absence of visible gallstone on plain abdominal x-ray does not always preclude calcification. This study aims to compare the response and dissolution rates between ursodeoxycholic acid (UDCA) alone or in combination with chenodeoxycholic acid (CDCA) according to stone density on computed tomography (CT) scan. A total of 126 patients underwent dissolution therapy with either UDCA alone or combination of CDCA and UDCA (CNU) from December 2010 to March 2014 at Korea University Ansan Hospital. In the end, 81 patients (CNU group = 44, UDCA group = 37) completed dissolution therapy for 6 months. Dissolution rate (percentage reduction in the gallstone volume) and response to therapy (complete dissolution or partial dissolution defined as reduction in stone volume of >50%) were compared between the 2 groups. Dissolution and response rates of sludge was also compared between the 2 groups. The overall response rate was 50.6% (CNU group 43.2% vs UDCA group 59.5%, P = 0.14), and the overall dissolution rate was 48.34% (CNU group 41.5% vs UDCA group 56.5%, P = 0.13). When analyzed according to stone density, response rate was 33.3%, 87.1%, 30.0%, and 6.2% for hypodense, isodense, hyperdense, and calcified stones, respectively. Response rate (85.7% vs 88.2%, P = 0.83) and dissolution rate (81.01% vs 85.38%, P = 0.17) of isodense stones were similar between CNU and UDCA group. When only sludge was considered, the overall response rate was 87.5% (CNU group 71.4% vs UDCA group 94.1%, P = 0.19), and the overall dissolution rate was 85.42% (CNU group 67.9% vs UDCA group 92.7%, P = 0.23). Patients with isodense gallstones and sludge showed much better response to dissolution therapy with CNU and UDCA showing comparable efficacy. Therefore, CT scan should be performed before medication therapy if stone dissolution is intended

  12. Repositioning accuracy of two different mask systems-3D revisited: Comparison using true 3D/3D matching with cone-beam CT

    SciTech Connect

    Boda-Heggemann, Judit . E-mail: judit.boda-heggemann@radonk.ma.uni-heidelberg.de; Walter, Cornelia; Rahn, Angelika; Wertz, Hansjoerg; Loeb, Iris; Lohr, Frank; Wenz, Frederik

    2006-12-01

    Purpose: The repositioning accuracy of mask-based fixation systems has been assessed with two-dimensional/two-dimensional or two-dimensional/three-dimensional (3D) matching. We analyzed the accuracy of commercially available head mask systems, using true 3D/3D matching, with X-ray volume imaging and cone-beam CT. Methods and Materials: Twenty-one patients receiving radiotherapy (intracranial/head-and-neck tumors) were evaluated (14 patients with rigid and 7 with thermoplastic masks). X-ray volume imaging was analyzed online and offline separately for the skull and neck regions. Translation/rotation errors of the target isocenter were analyzed. Four patients were treated to neck sites. For these patients, repositioning was aided by additional body tattoos. A separate analysis of the setup error on the basis of the registration of the cervical vertebra was performed. The residual error after correction and intrafractional motility were calculated. Results: The mean length of the displacement vector for rigid masks was 0.312 {+-} 0.152 cm (intracranial) and 0.586 {+-} 0.294 cm (neck). For the thermoplastic masks, the value was 0.472 {+-} 0.174 cm (intracranial) and 0.726 {+-} 0.445 cm (neck). Rigid masks with body tattoos had a displacement vector length in the neck region of 0.35 {+-} 0.197 cm. The intracranial residual error and intrafractional motility after X-ray volume imaging correction for rigid masks was 0.188 {+-} 0.074 cm, and was 0.134 {+-} 0.14 cm for thermoplastic masks. Conclusions: The results of our study have demonstrated that rigid masks have a high intracranial repositioning accuracy per se. Given the small residual error and intrafractional movement, thermoplastic masks may also be used for high-precision treatments when combined with cone-beam CT. The neck region repositioning accuracy was worse than the intracranial accuracy in both cases. However, body tattoos and image guidance improved the accuracy. Finally, the combination of both mask

  13. Prospective Evaluation of Prior Image Constrained Compressed Sensing (PICCS) Algorithm in Abdominal CT: A comparison of reduced dose with standard dose imaging

    PubMed Central

    Lubner, Meghan G.; Pickhardt, Perry J.; Kim, David H.; Tang, Jie; Munoz del Rio, Alejandro; Chen, Guang-Hong

    2014-01-01

    Purpose To prospectively study CT dose reduction using the “prior image constrained compressed sensing” (PICCS) reconstruction technique. Methods Immediately following routine standard dose (SD) abdominal MDCT, 50 patients (mean age, 57.7 years; mean BMI, 28.8) underwent a second reduced-dose (RD) scan (targeted dose reduction, 70-90%). DLP, CTDIvol and SSDE were compared. Several reconstruction algorithms (FBP, ASIR, and PICCS) were applied to the RD series. SD images with FBP served as reference standard. Two blinded readers evaluated each series for subjective image quality and focal lesion detection. Results Mean DLP, CTDIvol, and SSDE for RD series was 140.3 mGy*cm (median 79.4), 3.7 mGy (median 1.8), and 4.2 mGy (median 2.3) compared with 493.7 mGy*cm (median 345.8), 12.9 mGy (median 7.9 mGy) and 14.6 mGy (median 10.1) for SD series, respectively. Mean effective patient diameter was 30.1 cm (median 30), which translates to a mean SSDE reduction of 72% (p<0.001). RD-PICCS image quality score was 2.8±0.5, improved over the RD-FBP (1.7±0.7) and RD-ASIR(1.9±0.8)(p<0.001), but lower than SD (3.5±0.5)(p<0.001). Readers detected 81% (184/228) of focal lesions on RD-PICCS series, versus 67% (153/228) and 65% (149/228) for RD-FBP and RD-ASIR, respectively. Mean image noise was significantly reduced on RD-PICCS series (13.9 HU) compared with RD-FBP (57.2) and RD-ASIR (44.1) (p<0.001). Conclusion PICCS allows for marked dose reduction at abdominal CT with improved image quality and diagnostic performance over reduced-dose FBP and ASIR. Further study is needed to determine indication-specific dose reduction levels that preserve acceptable diagnostic accuracy relative to higher-dose protocols. PMID:24943136

  14. Comparison of proton therapy treatment planning for head tumors with a pencil beam algorithm on dual and single energy CT images

    SciTech Connect

    Hudobivnik, Nace; Dedes, George; Parodi, Katia; Landry, Guillaume; Schwarz, Florian; Johnson, Thorsten; Sommer, Wieland H.; Agolli, Linda; Tessonnier, Thomas; Verhaegen, Frank; Thieke, Christian; Belka, Claus

    2016-01-15

    Purpose: Dual energy CT (DECT) has recently been proposed as an improvement over single energy CT (SECT) for stopping power ratio (SPR) estimation for proton therapy treatment planning (TP), thereby potentially reducing range uncertainties. Published literature investigated phantoms. This study aims at performing proton therapy TP on SECT and DECT head images of the same patients and at evaluating whether the reported improved DECT SPR accuracy translates into clinically relevant range shifts in clinical head treatment scenarios. Methods: Two phantoms were scanned at a last generation dual source DECT scanner at 90 and 150 kVp with Sn filtration. The first phantom (Gammex phantom) was used to calibrate the scanner in terms of SPR while the second served as evaluation (CIRS phantom). DECT images of five head trauma patients were used as surrogate cancer patient images for TP of proton therapy. Pencil beam algorithm based TP was performed on SECT and DECT images and the dose distributions corresponding to the optimized proton plans were calculated using a Monte Carlo (MC) simulation platform using the same patient geometry for both plans obtained from conversion of the 150 kVp images. Range shifts between the MC dose distributions from SECT and DECT plans were assessed using 2D range maps. Results: SPR root mean square errors (RMSEs) for the inserts of the Gammex phantom were 1.9%, 1.8%, and 1.2% for SECT phantom calibration (SECT{sub phantom}), SECT stoichiometric calibration (SECT{sub stoichiometric}), and DECT calibration, respectively. For the CIRS phantom, these were 3.6%, 1.6%, and 1.0%. When investigating patient anatomy, group median range differences of up to −1.4% were observed for head cases when comparing SECT{sub stoichiometric} with DECT. For this calibration the 25th and 75th percentiles varied from −2% to 0% across the five patients. The group median was found to be limited to 0.5% when using SECT{sub phantom} and the 25th and 75th percentiles

  15. NETL CT Imaging Facility

    ScienceCinema

    None

    2016-07-12

    NETL's CT Scanner laboratory is equipped with three CT scanners and a mobile core logging unit that work together to provide characteristic geologic and geophysical information at different scales, non-destructively.

  16. Body CT (CAT Scan)

    MedlinePlus

    ... may increase the risk of an unusual adverse effect. Women should always inform their physician and the CT ... of data to create two-dimensional cross-sectional images of your body, which are then displayed on a monitor. CT ...

  17. Comparison of observer reliability of three-dimensional cephalometric landmark identification on subject images from Galileos and i-CAT cone beam CT

    PubMed Central

    Katkar, R A; Kummet, C; Dawson, D; Moreno Uribe, L; Allareddy, V; Finkelstein, M; Ruprecht, A

    2013-01-01

    Objectives: Recently, there has been increasing interest in the use of cone beam CT (CBCT) for three-dimensional cephalometric analysis and craniofacial reconstruction in orthodontic and orthognathic surgical treatment planning. However, there is a need to redefine the cephalometric landmarks in three dimensional cephalometric analysis and to demonstrate the reproducibility of landmark identification on the type of CBCT machine being used. Methods: CBCT images of 20 subjects aged 15–25 years were selected, ten each from Galileos® (Sirona Dental Systems Inc., Bensheim, Germany) and Next Generation i-CAT® (Imaging Sciences International, Hatfield, PA). 2 observers located 18 landmarks on each subject twice using Dolphin-3D v. 11 software (Dolphin Imaging and Management Systems, Chatsworth, CA). Inter- and intraobserver reliability was assessed using Euclidean distances and linear mixed models. Results: Overall, the intra- and interobserver reliability was excellent for both machines. The landmarks Gonion, Nasion, Orbitale and Anterior Nasal Spine (ANS) showed the greatest median Euclidean distances for both intra- and interobserver measurements. There were significant observer effects in the unified models for Sella, Menton and all six dental landmarks. For Sella, the distances between the measures were significantly smaller (more closely spaced) on the i-CAT machine than on the Galileos in both intra- and interobserver measurements. Conclusions: The intra- and interobserver reliability was excellent for both machines. Some of the landmarks were not as reproducible as others. Which machine produced the highest reliability depended on the landmark considered. PMID:23833319

  18. Evaluation of the cone beam CT for internal target volume localization in lung stereotactic radiotherapy in comparison with 4D MIP images

    SciTech Connect

    Wang, Lu; Chen, Xiaoming; Lin, Mu-Han; Lin, Teh; Fan, Jiajin; Jin, Lihui; Ma, Charlie M.; Xue, Jun

    2013-11-15

    Purpose: To investigate whether the three-dimensional cone-beam CT (CBCT) is clinically equivalent to the four-dimensional computed tomography (4DCT) maximum intensity projection (MIP) reconstructed images for internal target volume (ITV) localization in image-guided lung stereotactic radiotherapy.Methods: A ball-shaped polystyrene phantom with built-in cube, sphere, and cone of known volumes was attached to a motor-driven platform, which simulates a sinusoidal movement with changeable motion amplitude and frequency. Target motion was simulated in the patient in a superior-inferior (S-I) direction with three motion periods and 2 cm peak-to-peak amplitudes. The Varian onboard Exact-Arms kV CBCT system and the GE LightSpeed four-slice CT integrated with the respiratory-position-management 4DCT scanner were used to scan the moving phantom. MIP images were generated from the 4DCT images. The clinical equivalence of the two sets of images was evaluated by comparing the extreme locations of the moving objects along the motion direction, the centroid position of the ITV, and the ITV volumes that were contoured automatically by Velocity or calculated with an imaging gradient method. The authors compared the ITV volumes determined by the above methods with those theoretically predicted by taking into account the physical object dimensions and the motion amplitudes. The extreme locations were determined by the gradient method along the S-I axis through the center of the object. The centroid positions were determined by autocenter functions. The effect of motion period on the volume sizes was also studied.Results: It was found that the extreme locations of the objects determined from the two image modalities agreed with each other satisfactorily. They were not affected by the motion period. The average difference between the two modalities in the extreme locations was 0.68% for the cube, 1.35% for the sphere, and 0.5% for the cone, respectively. The maximum difference in the

  19. Comparison of linear and angular measurements using two-dimensional conventional methods and three-dimensional cone beam CT images reconstructed from a volumetric rendering program in vivo

    PubMed Central

    Oz, U; Orhan, K; Abe, N

    2011-01-01

    Objective The aim of this study was to compare the linear and angular measurements made on two-dimensional (2D) conventional cephalometric images and three-dimensional (3D) cone beam CT (CBCT) generated cephalograms derived from a 3D volumetric rendering program. Methods Pre-treatment cephalometric digital radiographs of 11 patients and their corresponding CBCT images were randomly selected. The digital cephalometric radiographs were traced using Vista Dent OC (GAC International, Inc Bohemia, NY) and by hand. CBCT and Maxilim® (Medicim, Sint-Niklass, Belgium) software were used to generate cephalograms from the CBCT data set that were then linked to the 3D hard-tissue surface representations. In total, 16 cephalometric landmarks were identified and 18 widely used measurements (11 linear and 7 angular) were performed by 2 independent observers. Intraobserver reliability was assessed by calculating intraclass correlation coefficients (ICC), interobserver reliability was assessed with Student t-test and analysis of variance (ANOVA). Mann–Whitney U-tests and Kruskal–Wallis H tests were also used to compare the three methods (P < 0.05). Results The results demonstrated no statistically significant difference between interobserver analyses for CBCT-generated cephalograms (P < 0.05), except for Gonion-Menton (Go-Me) and Condylion-Gnathion (Co-Gn). Intraobserver examinations showed low ICCs, which was an indication of poor reproducibility for Go-Me and Sella-Nasion (S-N) in CBCT-generated cephalograms and poor reproducibility for Articulare-Gonion (Ar-Go) in the 2D hand tracing method (P < 0.05). No statistical significance was found for Vista Dent OC measurements (P > 0.05). Conclusions Measurements from in vivo CBCT-generated cephalograms from Maxilim® software were found to be similar to conventional images. Thus, owing to higher radiation exposure, CBCT examinations should only be used when the inherent 3D information could improve the outcome of treatment. PMID

  20. [Value of (99)Tc(m)-MDP SPECT/CT in clinical decision-making for nasopharyngeal carcinoma and a comparison of the values of different imaging techniques for diagnosing skull-base bone invasion].

    PubMed

    Li, W; Zhang, R S; Zhang, L Q; Lu, B G; Fu, W H

    2017-02-23

    Objective: To analyze the clinical value of SPECT/CT in diagnosis of skull base bone invasion and clinical decision-making for nasopharyngeal carcinoma (NPC), and to compare their diagnostic value with SPECT/CT, CT, MRI, and MRI combined with SPECT (MRI-SPECT) for skull base bone invasion. Methods: Before treatment, among 348 newly diagnosed NPC patients, CT scan was performed in 186 patients (group A) and the remaining 162 patients received MRI scan (group B). Clinical doctors then made clinical management decisions according to the CT or MRI results. After that, all patients underwent (99)Tc(m)-MDP SPECT/CT examination for nasopharyngeal local tomography, and the results were provided to the clinical doctors to make clinical management decisions again. The changes between the two clinical management decisions were scored according to diagnosis, range of lesion, staging, treatment regimens, and auxiliary examination. The diagnostic value of CT scan, MRI scan, SPECT/CT and MRI-SPECT for skull base bone invasion was then evaluated and compared. Results: In terms of changes in scores of clinical management decisions, the score of group A was 1.387 and group B was 0.951, showing a significant difference between the two groups by Wilcoxon test (Z=6.570, P<0.001). By χ(2) test, there were correlations between CT and SPECT/CT (χ(2) =98.495, P<0.001), and between MRI and SPECT/CT (χ(2) =32.662, P<0.001). The consistency of CT and SPECT/CT (Kappa=0.713) was greater than MRI and SPECT (Kappa=0.449). The sensitivity of CT, MRI, SPECT/CT and MRI-SPECT was 67.1%, 84.5%, 90.8% and 100%, the specificity was 73.3%, 92.3%, 85.6% and 84.6%, and the area under the ROC curve was 0.702, 0.884, 0.882 and 0.923, respectively. Conclusions: SPECT/CT has important impact on clinical management decision for NPC. In the judgement of skull base invasion, the diagnostic value of SPECT/CT is significantly higher than CT and approximately equal to MRI. SPECT/CT should be one of the routine

  1. Comparison of the effectiveness of using the optic strut and tuberculum sellae as radiological landmarks in diagnosing paraclinoid aneurysms with CT angiography.

    PubMed

    Liao, Chih-Hsiang; Lin, Chung-Jung; Lin, Chun-Fu; Huang, Hsin-Yi; Chen, Min-Hsiung; Hsu, Sanford P C; Shih, Yang-Hsin

    2016-08-01

    OBJECTIVE The treatment of paraclinoid aneurysms remains challenging. It is important to determine the exact location of the paraclinoid aneurysm when considering treatment options. The authors herein evaluated the effectiveness of using the optic strut (OS) and tuberculum sellae (TS) as radiographic landmarks for distinguishing between intradural and extradural paraclinoid aneurysms on source images from CT angiography (CTA). METHODS Between January 2010 and September 2013, a total of 49 surgical patients with the preoperative diagnoses of paraclinoid aneurysm and 1 symptomatic cavernous-clinoid aneurysm were retrospectively identified. With the source images from CTA, the OS and the TS were used as landmarks to predict the location of the paraclinoid aneurysm and its relation to the distal dural ring (DDR). The operative findings were examined to confirm the definitive location of the paraclinoid aneurysm. Statistical analysis was performed to determine the diagnostic effectiveness of the landmarks. RESULTS Nineteen patients without preoperative CTA were excluded. The remaining 30 patients comprised the current study. The intraoperative findings confirmed 12 intradural, 12 transitional, and 6 extradural paraclinoid aneurysms, the diagnoses of which were significantly related to the type of aneurysm (p < 0.05) but not factors like sex, age, laterality of aneurysm, or relation of the aneurysm to the ophthalmic artery on digital subtraction angiography. To measure agreement with the correct diagnosis, the OS as a reference point was far superior to the TS (Cohen's kappa coefficients 0.462 and 0.138 for the OS and the TS, respectively). For paraclinoid aneurysms of the medial or posterior type, using the base of the OS as a reference point tended to overestimate intradural paraclinoid aneurysms. The receiver operating characteristic curve indicated that if the aneurysmal neck traverses the axial plane 2 mm above the base of the OS, the aneurysm is most likely to grow

  2. Effect of Stratified Care for Low Back Pain in Family Practice (IMPaCT Back): A Prospective Population-Based Sequential Comparison

    PubMed Central

    Foster, Nadine E.; Mullis, Ricky; Hill, Jonathan C.; Lewis, Martyn; Whitehurst, David G. T.; Doyle, Carol; Konstantinou, Kika; Main, Chris; Somerville, Simon; Sowden, Gail; Wathall, Simon; Young, Julie; Hay, Elaine M.

    2014-01-01

    PURPOSE We aimed to determine the effects of implementing risk-stratified care for low back pain in family practice on physician’s clinical behavior, patient outcomes, and costs. METHODS The IMPaCT Back Study (IMplementation to improve Patient Care through Targeted treatment) prospectively compared separate patient cohorts in a preintervention phase (6 months of usual care) and a postintervention phase (12 months of stratified care) in family practice, involving 64 family physicians and linked physical therapy services. A total of 1,647 adults with low back pain were invited to participate. Stratified care entailed use of a risk stratification tool to classify patients into groups at low, medium, or high risk for persistent disability and provision of risk-matched treatment. The primary outcome was 6-month change in disability as assessed with the Roland-Morris Disability Questionnaire. Process outcomes captured physician behavior change in risk-appropriate referral to physical therapy, diagnostic tests, medication prescriptions, and sickness certifications. A cost-utility analysis estimated incremental quality-adjusted life-years and back-related health care costs. Analysis was by intention to treat. RESULTS The 922 patients studied (368 in the preintervention phase and 554 in the postintervention phase) had comparable baseline characteristics. At 6 months follow-up, stratified care had a small but significant benefit relative to usual care as seen from a mean difference in Roland-Morris Disability Questionnaire scores of 0.7 (95% CI, 0.1–1.4), with a large, clinically important difference in the high risk group of 2.3 (95% CI, 0.8–3.9). Mean time off work was 50% shorter (4 vs 8 days, P = .03) and the proportion of patients given sickness certifications was 30% lower (9% vs 15%, P = .03) in the postintervention cohort. Health care cost savings were also observed. CONCLUSIONS Stratified care for back pain implemented in family practice leads to significant

  3. Image quality of CT angiography with model-based iterative reconstruction in young children with congenital heart disease: comparison with filtered back projection and adaptive statistical iterative reconstruction.

    PubMed

    Son, Sung Sil; Choo, Ki Seok; Jeon, Ung Bae; Jeon, Gye Rok; Nam, Kyung Jin; Kim, Tae Un; Yeom, Jeong A; Hwang, Jae Yeon; Jeong, Dong Wook; Lim, Soo Jin

    2015-06-01

    To retrospectively evaluate the image quality of CT angiography (CTA) reconstructed by model-based iterative reconstruction (MBIR) and to compare this with images obtained by filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR) in newborns and infants with congenital heart disease (CHD). Thirty-seven children (age 4.8 ± 3.7 months; weight 4.79 ± 0.47 kg) with suspected CHD underwent CTA on a 64detector MDCT without ECG gating (80 kVp, 40 mA using tube current modulation). Total dose length product was recorded in all patients. Images were reconstructed using FBP, ASIR, and MBIR. Objective image qualities (density, noise) were measured in the great vessels and heart chambers. The contrast-to-noise ratio (CNR) was calculated by measuring the density and noise of myocardial walls. Two radiologists evaluated images for subjective noise, diagnostic confidence, and sharpness at the level prior to the first branch of the main pulmonary artery. Images were compared with respect to reconstruction method, and reconstruction times were measured. Images from all patients were diagnostic, and the effective dose was 0.22 mSv. The objective image noise of MBIR was significantly lower than those of FBP and ASIR in the great vessels and heart chambers (P < 0.05); however, with respect to attenuations in the four chambers, ascending aorta, descending aorta, and pulmonary trunk, no statistically significant difference was observed among the three methods (P > 0.05). Mean CNR values were 8.73 for FBP, 14.54 for ASIR, and 22.95 for MBIR. In addition, the subjective image noise of MBIR was significantly lower than those of the others (P < 0.01). Furthermore, while FBP had the highest score for image sharpness, ASIR had the highest score for diagnostic confidence (P < 0.05), and mean reconstruction times were 5.1 ± 2.3 s for FBP and ASIR and 15.1 ± 2.4 min for MBIR. While CTA with MBIR in newborns and infants with CHD can reduce image noise and

  4. SU-E-J-47: Comparison of Online Image Registrations of Varian TrueBeam Cone-Beam CT and BrainLab ExacTrac Imaging Systems

    SciTech Connect

    Li, J; Shi, W; Andrews, D; Werner-Wasik, M; Yu, Y; Liu, H

    2015-06-15

    Purpose To compare online image registrations of TrueBeam cone-beam CT (CBCT) and BrainLab ExacTrac imaging systems. Methods Tests were performed on a Varian TrueBeam STx linear accelerator (Version 2.0), which is integrated with a BrainLab ExacTrac imaging system (Version 6.0.5). The study was focused on comparing the online image registrations for translational shifts. A Rando head phantom was placed on treatment couch and immobilized with a BrainLab mask. The phantom was shifted by moving the couch translationally for 8 mm with a step size of 1 mm, in vertical, longitudinal, and lateral directions, respectively. At each location, the phantom was imaged with CBCT and ExacTrac x-ray. CBCT images were registered with TrueBeam and ExacTrac online registration algorithms, respectively. And ExacTrac x-ray image registrations were performed. Shifts calculated from different registrations were compared with nominal couch shifts. Results The averages and ranges of absolute differences between couch shifts and calculated phantom shifts obtained from ExacTrac x-ray registration, ExacTrac CBCT registration with default window, ExaxTrac CBCT registration with adjusted window (bone), Truebeam CBCT registration with bone window, and Truebeam CBCT registration with soft tissue window, were: 0.07 (0.02–0.14), 0.14 (0.01–0.35), 0.12 (0.02–0.28), 0.09 (0–0.20), and 0.06 (0–0.10) mm, in vertical direction; 0.06 (0.01–0.12), 0.27 (0.07–0.57), 0.23 (0.02–0.48), 0.04 (0–0.10), and 0.08 (0– 0.20) mm, in longitudinal direction; 0.05 (0.01–0.21), 0.35 (0.14–0.80), 0.25 (0.01–0.56), 0.19 (0–0.40), and 0.20 (0–0.40) mm, in lateral direction. Conclusion The shifts calculated from ExacTrac x-ray and TrueBeam CBCT registrations were close to each other (the differences between were less than 0.40 mm in any direction), and had better agreements with couch shifts than those from ExacTrac CBCT registrations. There were no significant differences between True

  5. Accuracy of Ultrasound-Based Image Guidance for Daily Positioning of the Upper Abdomen: An Online Comparison With Cone Beam CT

    SciTech Connect

    Boda-Heggemann, Judit Mennemeyer, Philipp; Wertz, Hansjoerg; Riesenacker, Nadja; Kuepper, Beate; Lohr, Frank; Wenz, Frederik

    2009-07-01

    Purpose: Image-guided intensity-modulated radiotherapy can improve protection of organs at risk when large abdominal target volumes are irradiated. We estimated the daily positioning accuracy of ultrasound-based image guidance for abdominal target volumes by a direct comparison of daily imaging obtained with cone beam computed tomography (CBCT). Methods and Materials: Daily positioning (n = 83 positionings) of 15 patients was completed by using ultrasound guidance after an initial CBCT was obtained. Residual error after ultrasound was estimated by comparison with a second CBCT. Ultrasound image quality was visually rated using a scale of 1 to 4. Results: Of 15 patients, 7 patients had good sonographic imaging quality, 5 patients had satisfactory sonographic quality, and 3 patients were excluded because of unsatisfactory sonographic quality. When image quality was good, residual errors after ultrasound were -0.1 {+-} 3.11 mm in the x direction (left-right; group systematic error M = -0.09 mm; standard deviation [SD] of systematic error, {sigma} = 1.37 mm; SD of the random error, {sigma} = 2.99 mm), 0.93 {+-} 4.31 mm in the y direction (superior-inferior, M = 1.12 mm; {sigma} = 2.96 mm; {sigma} = 3.39 mm), and 0.71 {+-} 3.15 mm in the z direction (anteroposterior; M = 1.01 mm; {sigma} = 2.46 mm; {sigma} = 2.24 mm). For patients with satisfactory image quality, residual error after ultrasound was -0.6 {+-} 5.26 mm in the x (M = 0.07 mm; {sigma} = 5.67 mm; {sigma} = 4.86 mm), 1.76 {+-} 4.92 mm in the y (M = 3.54 mm; {sigma} = 4.1 mm; {sigma} = 5.29 mm), and 1.19 {+-} 4.75 mm in the z (M = 0.82 mm; {sigma} = 2.86 mm; {sigma} = 3.05 mm) directions. Conclusions: In patients from whom good sonographic image quality could be obtained, ultrasound improved daily positioning accuracy. In the case of satisfactory image quality, ultrasound guidance improved accuracy compared to that of skin marks only minimally. If sonographic image quality was unsatisfactory, daily CBCT

  6. Flat-detector computed tomography (FD-CT).

    PubMed

    Kalender, Willi A; Kyriakou, Yiannis

    2007-11-01

    Flat-panel detectors or, synonymously, flat detectors (FDs) have been developed for use in radiography and fluoroscopy with the defined goal to replace standard X-ray film, film-screen combinations and image intensifiers by an advanced sensor system. FD technology in comparison to X-ray film and image intensifiers offers higher dynamic range, dose reduction, fast digital readout and the possibility for dynamic acquisitions of image series, yet keeping to a compact design. It appeared logical to employ FD designs also for computed tomography (CT) imaging. Respective efforts date back a few years only, but FD-CT has meanwhile become widely accepted for interventional and intra-operative imaging using C-arm systems. FD-CT provides a very efficient way of combining two-dimensional (2D) radiographic or fluoroscopic and 3D CT imaging. In addition, FD technology made its way into a number of dedicated CT scanner developments, such as scanners for the maxillo-facial region or for micro-CT applications. This review focuses on technical and performance issues of FD technology and its full range of applications for CT imaging. A comparison with standard clinical CT is of primary interest. It reveals that FD-CT provides higher spatial resolution, but encompasses a number of disadvantages, such as lower dose efficiency, smaller field of view and lower temporal resolution. FD-CT is not aimed at challenging standard clinical CT as regards to the typical diagnostic examinations; but it has already proven unique for a number of dedicated CT applications, offering distinct practical advantages, above all the availability of immediate CT imaging in the interventional suite or the operating room.

  7. Prospective study evaluating the relative sensitivity of 18F-NaF PET/CT for detecting skeletal metastases from renal cell carcinoma in comparison to multidetector CT and 99mTc-MDP bone scintigraphy, using an adaptive trial design

    PubMed Central

    Gerety, E. L.; Lawrence, E. M.; Wason, J.; Yan, H.; Hilborne, S.; Buscombe, J.; Cheow, H. K.; Shaw, A. S.; Bird, N.; Fife, K.; Heard, S.; Lomas, D. J.; Matakidou, A.; Soloviev, D.; Eisen, T.; Gallagher, F. A.

    2015-01-01

    Background The detection of occult bone metastases is a key factor in determining the management of patients with renal cell carcinoma (RCC), especially when curative surgery is considered. This prospective study assessed the sensitivity of 18F-labelled sodium fluoride in conjunction with positron emission tomography/computed tomography (18F-NaF PET/CT) for detecting RCC bone metastases, compared with conventional imaging by bone scintigraphy or CT. Patients and methods An adaptive two-stage trial design was utilized, which was stopped after the first stage due to statistical efficacy. Ten patients with stage IV RCC and bone metastases were imaged with 18F-NaF PET/CT and 99mTc-labelled methylene diphosphonate (99mTc-MDP) bone scintigraphy including pelvic single photon emission computed tomography (SPECT). Images were reported independently by experienced radiologists and nuclear medicine physicians using a 5-point scoring system. Results Seventy-seven lesions were diagnosed as malignant: 100% were identified by 18F-NaF PET/CT, 46% by CT and 29% by bone scintigraphy/SPECT. Standard-of-care imaging with CT and bone scintigraphy identified 65% of the metastases reported by 18F-NaF PET/CT. On an individual patient basis, 18F-NaF PET/CT detected more RCC metastases than 99mTc-MDP bone scintigraphy/SPECT or CT alone (P = 0.007). The metabolic volumes, mean and maximum standardized uptake values (SUVmean and SUVmax) of the malignant lesions were significantly greater than those of the benign lesions (P < 0.001). Conclusions 18F-NaF PET/CT is significantly more sensitive at detecting RCC skeletal metastases than conventional bone scintigraphy or CT. The detection of occult bone metastases could greatly alter patient management, particularly in the context when standard-of-care imaging is negative for skeletal metastases. PMID:26202597

  8. CT angiography - chest

    MedlinePlus

    Computed tomography angiography - thorax; CTA - lungs; Pulmonary embolism - CTA chest; Thoracic aortic aneurysm - CTA chest; Venous thromboembolism - CTA lung; Blood clot - CTA lung; Embolus - CTA lung; CT ...

  9. PET/CT-Based Dosimetry in 90Y-Microsphere Selective Internal Radiation Therapy: Single Cohort Comparison With Pretreatment Planning on (99m)Tc-MAA Imaging and Correlation With Treatment Efficacy.

    PubMed

    Song, Yoo Sung; Paeng, Jin Chul; Kim, Hyo-Cheol; Chung, Jin Wook; Cheon, Gi Jeong; Chung, June-Key; Lee, Dong Soo; Kang, Keon Wook

    2015-06-01

    ⁹⁰Y PET/CT can be acquired after ⁹⁰Y-microsphere selective radiation internal therapy (SIRT) to describe radioactivity distribution. We performed dosimetry using ⁹⁰Y-microsphere PET/CT data to evaluate treatment efficacy and appropriateness of activity planning from (99m)Tc-MAA scan and SPECT/CT. Twenty-three patients with liver malignancy were included in the study. (99m)Tc-MAA was injected during planning angiography and whole body (99m)Tc-MAA scan and liver SPECT/CT were acquired. After SIRT using ⁹⁰Y-resin microsphere, ⁹⁰Y-microsphere PET/CT was acquired. A partition model (PM) using 4 compartments (tumor, intarget normal liver, out-target normal liver, and lung) was adopted, and absorbed dose to each compartment was calculated based on measurements from (99m)Tc-MAA SPECT/CT and ⁹⁰Y-microsphere PET/CT, respectively, to be compared with each other. Progression-free survival (PFS) was evaluated in terms of tumor absorbed doses calculated by (99m)Tc-MAA SPECT/CT and ⁹⁰Y-microsphere PET/CT results. Lung shunt fraction was overestimated on (99m)Tc-MAA scan compared with ⁹⁰Y-microsphere PET/CT (0.060 ± 0.037 vs. 0.018 ± 0.026, P < 0.01). Tumor absorbed dose exhibited a close correlation between the results from (99m)Tc-MAA SPECT/CT and ⁹⁰Y-microsphere PET/CT (r = 0.64, P < 0.01), although the result from (99m)Tc-MAA SPECT/CT was significantly lower than that from ⁹⁰Y-microsphere PET/CT (135.4 ± 64.2 Gy vs. 185.0 ± 87.8 Gy, P < 0.01). Absorbed dose to in-target normal liver was overestimated on (99m)Tc-MAA SPECT/CT compared with PET/CT (62.6 ± 38.2 Gy vs. 45.2 ± 32.0 Gy, P = 0.02). Absorbed dose to out-target normal liver did not differ between (99m)Tc-MAA SPECT/CT and ⁹⁰Y-microsphere PET/CT (P = 0.49). Patients with tumor absorbed dose >200 Gy on ⁹⁰Y-microsphere PET/CT had longer PFS than those with tumor absorbed dose ≤200 Gy (286 ± 56 days vs. 92 ± 20

  10. Intraindividual comparison of gadolinium- and iodine-enhanced 64-slice multidetector CT pulmonary angiography for the detection of pulmonary embolism in a porcine model.

    PubMed

    Henes, Frank Oliver Gerhard; Groth, Michael; Begemann, Philipp G C; Adam, Gerhard; Regier, Marc

    2011-06-01

    This study is an evaluation of the diagnostic accuracy of gadolinium-enhanced computed tomography pulmonary angiography (CTPA) for the detection of pulmonary embolism (PE) in comparison with iodine-enhanced CTPA. PE was induced in five anesthetized pigs by administration of blood clots through an 11-F catheter inside the jugular vein. Animals underwent CTPA in breathhold with i.v. bolus injection of 50 ml gadopentetate dimeglumine (0.4 mmol/kg, 4 ml/s). Subsequently, CTPA was performed using the same imaging parameters but under administration of 70 ml nonionic iodinated contrast material (400 mg/ml, 4 ml/s). All images were reconstructed with 1 mm slice thickness. A consensus readout of the iodium-enhanced CTPAs by both radiologists served as reference standard. Gadolinium-enhanced CTPAs were evaluated independently by two experienced radiologists, and differences in detection rate between both contrast agents were assessed on a per embolus basis using the Wilcoxon signed-rank test. Interobserver agreement was determined by calculation of қ values. PE was diagnosed independently by both readers in all five pigs by the use of gadolinium-enhanced CTPA. Out of 60 pulmonary emboli detected in the iodine-enhanced scans, 47 (78.3%; reader 1) and 44 (62.8%; reader 2) emboli were detected by the use of gadolinium. All 13 (100%) emboli in lobar arteries (by both readers) and 26 (reader 1) and 25 (reader 2) out of 27 emboli (96.3% and 92.6%) in segmental arteries were detected by the use of the gadolinium-enhanced CTPA. In subsegmental arteries, only 8 (40%; reader 1) and 6 (30%; reader 2) out of 20 emboli were detected by the gadolinium-enhanced CTPA. By comparing both scans on a per vessel basis (Wilcoxon test), Gd-enhanced CTPA was significantly inferior in emboli detection on subsegmental level (P < 0.0001). The interobserver agreement was excellent on lobar and segmental level (қ = 1.0 and 0.93, respectively), whereas readers only reached moderate

  11. CT imaging of enhanced oil recovery experiments

    SciTech Connect

    Gall, B.L.

    1992-12-01

    X-ray computerized tomography (Cr) has been used to study fluid distributions during chemical enhanced oil recovery experiments. Four CT-monitored corefloods were conducted, and oil saturation distributions were calculated at various stages of the experiments. Results suggested that this technique could add significant information toward interpretation and evaluation of surfactant/polymer EOR recovery methods. CT-monitored tracer tests provided information about flow properties in the core samples. Nonuniform fluid advance could be observed, even in core that appeared uniform by visual inspection. Porosity distribution maps based on CT density calculations also showed the presence of different porosity layers that affected fluid movement through the cores. Several types of CT-monitored corefloods were conducted. Comparisons were made for CT-monitored corefloods using chemical systems that were highly successful in reducing residual oil saturations in laboratory experiments and less successful systems. Changes were made in surfactant formulation and in concentration of the mobility control polymer. Use of a poor mobility control agent failed to move oil that was not initially displaced by the injected surfactant solution; even when a good'' surfactant system was used. Use of a less favorable surfactant system with adequate mobility control could produce as much oil as the use of a good surfactant system with inadequate mobility control. The role of mobility control, therefore, becomes a critical parameter for successful application of chemical EOR. Continuation of efforts to use CT imaging in connection with chemical EOR evaluations is recommended.

  12. CT imaging of enhanced oil recovery experiments

    SciTech Connect

    Gall, B.L.

    1992-12-01

    X-ray computerized tomography (Cr) has been used to study fluid distributions during chemical enhanced oil recovery experiments. Four CT-monitored corefloods were conducted, and oil saturation distributions were calculated at various stages of the experiments. Results suggested that this technique could add significant information toward interpretation and evaluation of surfactant/polymer EOR recovery methods. CT-monitored tracer tests provided information about flow properties in the core samples. Nonuniform fluid advance could be observed, even in core that appeared uniform by visual inspection. Porosity distribution maps based on CT density calculations also showed the presence of different porosity layers that affected fluid movement through the cores. Several types of CT-monitored corefloods were conducted. Comparisons were made for CT-monitored corefloods using chemical systems that were highly successful in reducing residual oil saturations in laboratory experiments and less successful systems. Changes were made in surfactant formulation and in concentration of the mobility control polymer. Use of a poor mobility control agent failed to move oil that was not initially displaced by the injected surfactant solution; even when a ``good`` surfactant system was used. Use of a less favorable surfactant system with adequate mobility control could produce as much oil as the use of a good surfactant system with inadequate mobility control. The role of mobility control, therefore, becomes a critical parameter for successful application of chemical EOR. Continuation of efforts to use CT imaging in connection with chemical EOR evaluations is recommended.

  13. Computed Tomography (CT) -- Sinuses

    MedlinePlus

    ... More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses uses special x-ray equipment to evaluate the paranasal sinus cavities – hollow, air-filled spaces within the bones of the face surrounding the ...

  14. Comparison of {sup 18}F-Fluorothymidine and {sup 18}F-Fluorodeoxyglucose PET/CT in Delineating Gross Tumor Volume by Optimal Threshold in Patients With Squamous Cell Carcinoma of Thoracic Esophagus

    SciTech Connect

    Han Dali; Yu Jinming; Yu Yonghua; Zhang Guifang; Zhong Xiaojun; Lu Jie; Yin Yong; Fu Zheng; Mu Dianbin; Zhang Baijiang; He Wei; Huo Zhijun; Liu Xijun; Kong Lei; Zhao Shuqiang; Sun Xiangyu

    2010-03-15

    Purpose: To determine the optimal method of using {sup 18}F-fluorothymidine (FLT) positron emission tomography (PET)/computed tomography (CT) simulation to delineate the gross tumor volume (GTV) in esophageal squamous cell carcinoma verified by pathologic examination and compare the results with those using {sup 18}F-fluorodeoxyglucose (FDG) PET/CT. Methods and Materials: A total of 22 patients were enrolled and underwent both FLT and FDG PET/CT. The GTVs with biologic information were delineated using seven different methods in FLT PET/CT and three different methods in FDG PET/CT. The results were compared with the pathologic gross tumor length, and the optimal threshold was obtained. Next, we compared the simulation plans using the optimal threshold of FLT and FDG PET/CT. The radiation dose was prescribed as 60 Gy in 30 fractions with a precise radiotherapy technique. Results: The mean +- standard deviation pathologic gross tumor length was 4.94 +- 2.21 cm. On FLT PET/CT, the length of the standardized uptake value 1.4 was 4.91 +- 2.43 cm. On FDG PET/CT, the length of the standardized uptake value 2.5 was 5.10 +- 2.18 cm, both of which seemed more approximate to the pathologic gross tumor length. The differences in the bilateral lung volume receiving >=20 Gy, heart volume receiving >=40 Gy, and the maximal dose received by spinal cord between FLT and FDG were not significant. However, the values for mean lung dose, bilateral lung volume receiving >=5, >=10, >=30, >=40, and >=50 Gy, mean heart dose, and heart volume receiving >=30 Gy using FLT PET/CT-based planning were significant lower than those using FDG PET/CT. Conclusion: A standardized uptake value cutoff of 1.4 on FLT PET/CT and one of 2.5 on FDG PET/CT provided the closest estimation of GTV length. Finally, FLT PET/CT-based treatment planning provided potential benefits to the lungs and heart.

  15. Randomized comparison of ticagrelor versus prasugrel in patients with acute coronary syndrome and planned invasive strategy--design and rationale of the iNtracoronary Stenting and Antithrombotic Regimen: Rapid Early Action for Coronary Treatment (ISAR-REACT) 5 trial.

    PubMed

    Schulz, Stefanie; Angiolillo, Dominick J; Antoniucci, David; Bernlochner, Isabell; Hamm, Christian; Jaitner, Juliane; Laugwitz, Karl-Ludwig; Mayer, Katharina; von Merzljak, Barbara; Morath, Tanja; Neumann, Franz-Josef; Richardt, Gert; Ruf, Judith; Schömig, Gisela; Schühlen, Helmut; Schunkert, Heribert; Kastrati, Adnan

    2014-02-01

    In acute coronary syndromes (ACS), a dual antiplatelet regimen with an adenosine diphosphate (ADP) receptor antagonist plus aspirin has become the cornerstone of treatment. The third-generation thienopyridine prasugrel and the cyclopentyl-triazolo-pyrimidine ticagrelor provide a greater, more rapid and consistent platelet inhibition compared to their predecessor clopidogrel. Based on their advantages over clopidogrel in two landmark studies, both drugs received a class I recommendation for their use in ACS patients with and without ST segment elevation. Due to differences in ACS populations and conditions investigated, the relative merits of ticagrelor versus prasugrel in the treatment of ACS patients with planned invasive strategy cannot be reliably estimated from independent trials. To date, no direct head-to-head comparison of ticagrelor and prasugrel in terms of clinical outcome exists. The aim of this multicenter, randomized, open-label trial is to assess whether ticagrelor is superior to prasugrel in ACS patients with planned invasive strategy.

  16. CT Angiography (CTA)

    MedlinePlus

    ... CT Angiography? Angiography is a minimally invasive medical test that helps physicians diagnose and treat medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ...

  17. Leg CT scan

    MedlinePlus

    CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... scanners can perform the exam without stopping.) A computer creates separate images of the body area, called ...

  18. Arm CT scan

    MedlinePlus

    CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm ... scanners can perform the exam without stopping.) A computer creates separate images of the arm area, called ...

  19. Computed Tomography (CT) -- Sinuses

    MedlinePlus Videos and Cool Tools

    ... to urinate; however, this is actually a contrast effect and subsides quickly. When you enter the CT scanner room, special light lines may be seen projected onto your body, and are used to ensure that you are ...

  20. Computed Tomography (CT) -- Head

    MedlinePlus Videos and Cool Tools

    ... to urinate; however, this is actually a contrast effect and subsides quickly. When you enter the CT scanner room, special light lines may be seen projected onto your body, and are used to ensure that you are ...

  1. Thoracic spine CT scan

    MedlinePlus

    ... Narrowing of the spine ( spinal stenosis ) Scoliosis Tumor Risks Risks of CT scans include: Exposure to radiation ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  2. Lumbar spine CT scan

    MedlinePlus

    CAT scan - lumbar spine; Computed axial tomography scan - lumbar spine; Computed tomography scan - lumbar spine; CT - lower back ... stopping.) A computer creates separate images of the spine area, called slices. These images can be stored, ...

  3. Pediatric CT Scans

    Cancer.gov

    The Radiation Epidemiology Branch and collaborators have initiated a retrospective cohort study to evaluate the relationship between radiation exposure from CT scans conducted during childhood and adolescence and the subsequent development of cancer.

  4. Body CT (CAT Scan)

    MedlinePlus

    ... lives. CT has been shown to be a cost-effective imaging tool for a wide range of ... accredited facilities database . This website does not provide cost information. The costs for specific medical imaging tests, ...

  5. Cardiac CT Scan

    MedlinePlus

    ... CT Scan Related Topics Aneurysm Coronary Calcium Scan Coronary Heart Disease Heart Attack Pulmonary Embolism Send a link to ... imaging test can help doctors detect or evaluate coronary heart disease, calcium buildup in the coronary arteries, problems with ...

  6. Characterizing anatomical variability in breast CT images

    PubMed Central

    Metheany, Kathrine G.; Abbey, Craig K.; Packard, Nathan; Boone, John M.

    2008-01-01

    Previous work [Burgess , Med. Phys. 28, 419–437 (2001)] has shown that anatomical noise in projection mammography results in a power spectrum well modeled over a range of frequencies by a power law, and the exponent (β) of this power law plays a critical role in determining the size at which a growing lesion reaches the threshold for detection. In this study, the authors evaluated the power-law model for breast computed tomography (bCT) images, which can be thought of as thin sections through a three-dimensional (3D) volume. Under the assumption of a 3D power law describing the distribution of attenuation coefficients in the breast parenchyma, the authors derived the relationship between the power-law exponents of bCT and projection images and found it to be βsection=βproj−1. They evaluated this relationship on clinical images by comparing bCT images from a set of 43 patients to Burgess’ findings in mammography. They were able to make a direct comparison for 6 of these patients who had both a bCT exam and a digitized film-screen mammogram. They also evaluated segmented bCT images to investigate the extent to which the bCT power-law exponent can be explained by a binary model of attenuation coefficients based on the different attenuation of glandular and adipose tissue. The power-law model was found to be a good fit for bCT data over frequencies from 0.07to0.45cyc∕mm, where anatomical variability dominates the spectrum. The average exponent for bCT images was 1.86. This value is close to the theoretical prediction using Burgess’ published data for projection mammography and for the limited set of mammography data available from the authors’ patient sample. Exponents from the segmented bCT images (average value: 2.06) were systematically slightly higher than bCT images, with substantial correlation between the two (r=0.84). PMID:18975714

  7. Comparison between endobronchial ultrasound-guided transbronchial biopsy and CT-guided transthoracic lung biopsy for the diagnosis of peripheral lung cancer: a systematic review and meta-analysis

    PubMed Central

    Zhan, Ping; Zhu, Qing-Qing; Miu, Ying-Ying; Liu, Ya-Fang; Wang, Xiao-Xia; Zhou, Ze-Jun; Jin, Jia-Jia; Li, Qian; Sasada, Shinji; Izumo, Takehiro; Tu, Chih-Yen; Cheng, Wen-Chien; Evison, Matthew

    2017-01-01

    Background With the release of the National Lung Screening Trial results, the detection of peripheral pulmonary lesions (PPLs) is likely to increase. Computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) and radial probe endobronchial ultrasound (r-EBUS)-guided transbronchial lung biopsy (TBLB) are recommended for tissue diagnosis of PPLs. Methods A systematic review of published literature evaluating the accuracy of r-EBUS-TBLB and CT-PTNB for the diagnosis of PPLs was performed to determine point sensitivity and specificity, and to construct a summary receiver-operating characteristic curve. Results This review included 31 publications dealing with EBUS-TBLB and 14 publications dealing with CT-PTNB for the diagnosis of PPLs. EBUS-TBLB had point sensitivity of 0.69 (95% CI: 0.67–0.71) for the diagnosis of peripheral lung cancer (PLC), which was lower than the sensitivity of CT-PTNB (0.94, 95% CI: 0.94–0.95). However, the complication rates observed with EBUS-TBLB were lower than those reported for CT-PTNB. Conclusions This meta-analysis showed that EBUS-TBLB is a safe and relatively accurate tool in the investigation of PLC. Although the yield remains lower than that of CT-PTNB, the procedural risks are lower. PMID:28331821

  8. CT of pituitary abscess

    SciTech Connect

    Fong, T.C.; Johns, R.D.; Long, M.; Myles, S.T.

    1985-06-01

    Pituitary abscess is a rare condition, with only 50 cases reported in the literature. Of those, 29 cases were well documented for analysis. Preoperative diagnosis of pituitary abscess is difficult. The computed tomographic (CT) appearance of pituitary abscess was first described in 1983; the abscess was depicted by axial images with coronal reconstruction. The authors recently encountered a case of pituitary abscess documented by direct coronal CT of the sella turcica.

  9. Internal noise in channelized Hotelling observer (CHO) study of detectability index-differential phase contrast CT vs. conventional CT

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Yang, Yi

    2014-03-01

    The channelized Hotelling observer (CHO) model, wherein internal noise plays an important role to account for the psychophysiological uncertainty in human's visual perception, has found extensive applications in the assessment of image quality in nuclear medicine, mammography and conventional CT. Recently, we extended its application to investigating the detectability index of differential phase contrast (DPC) CT-an emerging CT technology with the potential of increasing the capability in soft tissue differentiation. We found that the quantitative determination of internal noise in the CHO study of DPC-CT's detectability index should differ from that in the conventional CT. It is believed that the root cause of such a difference lies in the distinct noise spectra between the DPC-CT and conventional CT. In this paper, we present the preliminary results and investigate the adequate strategies to quantitatively determine the internal noise of CHO model for its application in the assessment of image quality in DPC-CT and its comparison with that of the conventional CT.

  10. Phantom based evaluation of CT to CBCT image registration for proton therapy dose recalculation

    NASA Astrophysics Data System (ADS)

    Landry, Guillaume; Dedes, George; Zöllner, Christoph; Handrack, Josefine; Janssens, Guillaume; Orban de Xivry, Jonathan; Reiner, Michael; Paganelli, Chiara; Riboldi, Marco; Kamp, Florian; Söhn, Matthias; Wilkens, Jan J.; Baroni, Guido; Belka, Claus; Parodi, Katia

    2015-01-01

    The ability to perform dose recalculation on the anatomy of the day is important in the context of adaptive proton therapy. The objective of this study was to investigate the use of deformable image registration (DIR) and cone beam CT (CBCT) imaging to generate the daily stopping power distribution of the patient. We investigated the deformation of the planning CT scan (pCT) onto daily CBCT images to generate a virtual CT (vCT) using a deformable phantom designed for the head and neck (H & N) region. The phantom was imaged at a planning CT scanner in planning configuration, yielding a pCT and in deformed, treatment day configuration, yielding a reference CT (refCT). The treatment day configuration was additionally scanned at a CBCT scanner. A Morphons DIR algorithm was used to generate a vCT. The accuracy of the vCT was evaluated by comparison to the refCT in terms of corresponding features as identified by an adaptive scale invariant feature transform (aSIFT) algorithm. Additionally, the vCT CT numbers were compared to those of the refCT using both profiles and regions of interest and the volumes and overlap (DICE coefficients) of various phantom structures were compared. The water equivalent thickness (WET) of the vCT, refCT and pCT were also compared to evaluate proton range differences. Proton dose distributions from the same initial fluence were calculated on the refCT, vCT and pCT and compared in terms of proton range. The method was tested on a clinical dataset using a replanning CT scan acquired close in time to a CBCT scan as reference using the WET evaluation. Results from the aSIFT investigation suggest a deformation accuracy of 2-3 mm. The use of the Morphon algorithm did not distort CT number intensity in uniform regions and WET differences between vCT and refCT were of the order of 2% of the proton range. This result was confirmed by proton dose calculations. The patient results were consistent with phantom observations. In conclusion, our phantom

  11. Test of 3D CT reconstructions by EM + TV algorithm from undersampled data

    SciTech Connect

    Evseev, Ivan; Ahmann, Francielle; Silva, Hamilton P. da

    2013-05-06

    Computerized tomography (CT) plays an important role in medical imaging for diagnosis and therapy. However, CT imaging is connected with ionization radiation exposure of patients. Therefore, the dose reduction is an essential issue in CT. In 2011, the Expectation Maximization and Total Variation Based Model for CT Reconstruction (EM+TV) was proposed. This method can reconstruct a better image using less CT projections in comparison with the usual filtered back projection (FBP) technique. Thus, it could significantly reduce the overall dose of radiation in CT. This work reports the results of an independent numerical simulation for cone beam CT geometry with alternative virtual phantoms. As in the original report, the 3D CT images of 128 Multiplication-Sign 128 Multiplication-Sign 128 virtual phantoms were reconstructed. It was not possible to implement phantoms with lager dimensions because of the slowness of code execution even by the CORE i7 CPU.

  12. MR Evaluation of the Nontraumatic Acute Abdomen with CT Correlation.

    PubMed

    Bannas, Peter; Pickhardt, Perry J

    2015-11-01

    Cross-sectional imaging plays a crucial role in the triage of patients with acute abdominal pain. Ionizing radiation exposure is a recognized drawback of computed tomography (CT), the primary imaging technique. MR imaging is a promising alternative to CT; it provides excellent image quality with high-contrast resolution without the disadvantages of ionizing radiation and iodinated contrast. This article provides a basic overview of the typical MR findings of the most frequent disease entities encountered in the setting of the nontraumatic acute abdomen, including direct comparison with CT findings to familiarize the readers with these same findings on MR.

  13. Diagnostic Accuracy of CT Enterography for Active Inflammatory Terminal Ileal Crohn Disease: Comparison of Full-Dose and Half-Dose Images Reconstructed with FBP and Half-Dose Images with SAFIRE.

    PubMed

    Gandhi, Namita S; Baker, Mark E; Goenka, Ajit H; Bullen, Jennifer A; Obuchowski, Nancy A; Remer, Erick M; Coppa, Christopher P; Einstein, David; Feldman, Myra K; Kanmaniraja, Devaraju; Purysko, Andrei S; Vahdat, Noushin; Primak, Andrew N; Karim, Wadih; Herts, Brian R

    2016-08-01

    Purpose To compare the diagnostic accuracy and image quality of computed tomographic (CT) enterographic images obtained at half dose and reconstructed with filtered back projection (FBP) and sinogram-affirmed iterative reconstruction (SAFIRE) with those of full-dose CT enterographic images reconstructed with FBP for active inflammatory terminal or neoterminal ileal Crohn disease. Materials and Methods This retrospective study was compliant with HIPAA and approved by the institutional review board. The requirement to obtain informed consent was waived. Ninety subjects (45 with active terminal ileal Crohn disease and 45 without Crohn disease) underwent CT enterography with a dual-source CT unit. The reference standard for confirmation of active Crohn disease was active terminal ileal Crohn disease based on ileocolonoscopy or established Crohn disease and imaging features of active terminal ileal Crohn disease. Data from both tubes were reconstructed with FBP (100% exposure); data from the primary tube (50% exposure) were reconstructed with FBP and SAFIRE strengths 3 and 4, yielding four datasets per CT enterographic examination. The mean volume CT dose index (CTDIvol) and size-specific dose estimate (SSDE) at full dose were 13.1 mGy (median, 7.36 mGy) and 15.9 mGy (median, 13.06 mGy), respectively, and those at half dose were 6.55 mGy (median, 3.68 mGy) and 7.95 mGy (median, 6.5 mGy). Images were subjectively evaluated by eight radiologists for quality and diagnostic confidence for Crohn disease. Areas under the receiver operating characteristic curves (AUCs) were estimated, and the multireader, multicase analysis of variance method was used to compare reconstruction methods on the basis of a noninferiority margin of 0.05. Results The mean AUCs with half-dose scans (FBP, 0.908; SAFIRE 3, 0.935; SAFIRE 4, 0.924) were noninferior to the mean AUC with full-dose FBP scans (0.908; P < .003). The proportion of images with inferior quality was significantly higher with all

  14. CT of abdominal tuberculosis

    SciTech Connect

    Epstein, B.M.; Mann, J.H.

    1982-11-01

    Intraabdominal tuberculosis (TB) presents with a wide variety of clinical and radiologic features. Besides the reported computed tomographic (CT) finding of high-density ascites in tuberculous peritonitis, this report describes additional CT features highly suggestive of abdominal tuberculosis in eight cases: (1) irregular soft-tissue densities in the omental area; (2) low-density masses surrounded by thick solid rims; (3) a disorganized appearance of soft-tissue densities, fluid, and bowel loops forming a poorly defined mass; (4) low-density lymph nodes with a multilocular appearance after intravenous contrast administration; and (5) possibly high-density ascites. The differential diagnosis of these features include lymphoma, various forms of peritonitis, peritoneal carcinomatosis, and peritoneal mesothelioma. It is important that the CT features of intraabdominal tuberculosis be recognized in order that laparotomy be avoided and less invasive procedures (e.g., laparoscopy, biopsy, or a trial of antituberculous therapy) be instituted.

  15. CT Perfusion of the Head

    MedlinePlus

    ... the machine as the actual CT scanning is performed. Depending on the type of CT scan, the machine may make several passes. The contrast material will then be injected through an intravenous line ( ...

  16. Research on radiation exposure from CT part of hybrid camera and diagnostic CT

    NASA Astrophysics Data System (ADS)

    Solný, Pavel; Zimák, Jaroslav

    2014-11-01

    Research on radiation exposure from CT part of hybrid camera in seven different Departments of Nuclear Medicine (DNM) was conducted. Processed data and effective dose (E) estimations led to the idea of phantom verification and comparison of absorbed doses and software estimation. Anonymous data from about 100 examinations from each DNM was gathered. Acquired data was processed and utilized by dose estimation programs (ExPACT, ImPACT, ImpactDose) with respect to the type of examination and examination procedures. Individual effective doses were calculated using enlisted programs. Preserving the same procedure in dose estimation process allows us to compare the resulting E. Some differences and disproportions during dose estimation led to the idea of estimated E verification. Consequently, two different sets of about 100 of TLD 100H detectors were calibrated for measurement inside the Aldersnon RANDO Anthropomorphic Phantom. Standard examination protocols were examined using a 2 Slice CT- part of hybrid SPECT/CT. Moreover, phantom exposure from body examining protocol for 32 Slice and 64 Slice diagnostic CT scanner was also verified. Absorbed dose (DT,R) measured using TLD detectors was compared with software estimation of equivalent dose HT values, computed by E estimation software. Though, only limited number of cavities for detectors enabled measurement within the regions of lung, liver, thyroid and spleen-pancreas region, some basic comparison is possible.

  17. Low-Dose PET/CT and Full-Dose Contrast-Enhanced CT at the Initial Staging of Localized Diffuse Large B-Cell Lymphomas

    PubMed Central

    Sabaté-Llobera, Aida; Cortés-Romera, Montserrat; Mercadal, Santiago; Hernández-Gañán, Javier; Pomares, Helena; González-Barca, Eva; Gámez-Cenzano, Cristina

    2016-01-01

    Computed tomography (CT) has been used as the reference imaging technique for the initial staging of diffuse large B-cell lymphoma until recent days, when the introduction of positron emission tomography (PET)/CT imaging as a hybrid technique has become of routine use. However, the performance of both examinations is still common. The aim of this work was to compare the findings between low-dose 2-deoxy-2-(18F)fluoro-d-glucose (18F-FDG) PET/CT and full-dose contrast-enhanced CT (ceCT) in 28 patients with localized diffuse large B-cell lymphoma according to PET/CT findings, in order to avoid the performance of ceCT. For each technique, a comparison in the number of nodal and extranodal involved regions was performed. PET/CT showed more lesions than ceCT in both nodal (41 vs. 36) and extranodal localizations (16 vs. 15). Disease staging according to both techniques was concordant in 22 patients (79%) and discordant in 6 patients (21%), changing treatment management in 3 patients (11%). PET/CT determined a better staging and therapeutic approach, making the performance of an additional ceCT unnecessary. PMID:27559300

  18. Technical aspects of CT angiography.

    PubMed

    Kuszyk, B S; Fishman, E K

    1998-10-01

    The basic tasks of spiral CT acquisition, image processing, and image display are the foundations underlying CT angiography regardless of the anatomic region of interest. Volume rendering is a rapidly emerging image processing technique for creating three-dimensional (3D) images from CT datasets, which has important advantages over other 3D rendering techniques including maximum intensity projection and surface rendering. This articles reviews the techniques that are commonly used in CT angiography and key considerations for optimization.

  19. Seventh-generation CT

    NASA Astrophysics Data System (ADS)

    Besson, G. M.

    2016-03-01

    A new dual-drum CT system architecture has been recently introduced with the potential to achieve significantly higher temporal resolution than is currently possible in medical imaging CT. The concept relies only on known technologies; in particular rotation speeds several times higher than what is possible today could be achieved leveraging typical x-ray tube designs and capabilities. However, the architecture lends itself to the development of a new arrangement of x-ray sources in a toroidal vacuum envelope containing a rotating cathode ring and a (optionally rotating) shared anode ring to potentially obtain increased individual beam power as well as increase total exposure per rotation. The new x-ray source sub-system design builds on previously described concepts and could make the provision of multiple conventional high-power cathodes in a CT system practical by distributing the anode target between the cathodes. In particular, relying on known magnetic-levitation technologies, it is in principle possible to more than double the relative speed of the electron-beam with respect to the target, thus potentially leading to significant individual beam power increases as compared to today's state-of-the-art. In one embodiment, the proposed design can be naturally leveraged by the dual-drum CT concept previously described to alleviate the problem of arranging a number of conventional rotating anode-stem x-ray tubes and power conditioners on the limited space of a CT gantry. In another embodiment, a system with three cathodes is suggested leveraging the architecture previously proposed by Franke.

  20. Imaging detection of new HCCs in cirrhotic patients treated with different techniques: Comparison of conventional US, spiral CT, and 3-dimensional contrast-enhanced US with the Navigator technique (Nav 3D CEUS)☆

    PubMed Central

    Giangregorio, F.; Comparato, G.; Marinone, M.G.; Di Stasi, M.; Sbolli, G.; Aragona, G.; Tansini, P.; Fornari, F.

    2009-01-01

    Introduction The commercially available Navigator system© (Esaote, Italy) allows easy 3D reconstruction of a single 2D acquisition of contrast-enhanced US (CEUS) imaging of the whole liver (with volumetric correction provided by the electromagnetic device of the Navigator©). The aim of our study was to compare the efficacy of this panoramic technique (Nav 3D CEUS) with that of conventional US and spiral CT in the detection of new hepatic lesions in patients treated for hepatocellular carcinoma (HCC). Materials and methods From November 2006 to May 2007, we performed conventional US, Nav 3D CEUS, and spiral CT on 72 cirrhotic patients previously treated for 1 or more HCCs (M/F: 38/34; all HCV-positive; Child: A/B 58/14) (1 examination: 48 patients; 2 examinations: 20 patients; 3 examinations: 4 patients). Nav 3D CEUS was performed with SonoVue© (Bracco, Milan, Italy) as a contrast agent and Technos MPX© scanner (Esaote, Genoa, Italy). Sensitivity, specificity, diagnostic accuracy, and positive and negative predictive values (PPV and NPV, respectively) were evaluated. Differences between the techniques were assessed with the chi-square test (SPSS release-15). Results Definitive diagnoses (based on spiral CT and additional follow-up) were: 6 cases of local recurrence (LocRecs) in 4 patients, 49 new nodules >2 cm from a treated nodule (NewNods) in 34 patients, and 10 cases of multinodular recurrence consisting of 4 or more nodules (NewMulti). The remaining 24 patients (22 treated for 1–3 nodules, 2 treated for >3 nodules) remained recurrence-free. Conventional US correctly detected 29/49 NewNods, 9/10 NewMultis, and 3/6 LocRecs (sensitivity: 59.2%; specificity: 100%; diagnostic accuracy: 73.6%; PPV: 100%; NPV: 70.1%). Spiral CT detected 42/49 NewNods plus 1 that was a false positive, 9/10 NewMultis, and all 6 LocRecs (sensitivity: 85.7%; specificity: 95.7%; diagnostic accuracy: 90.9%; PPV: 97.7%; NPV: 75.9%). 3D NAV results were: 46N (+9 multinodularN and 6 LR

  1. Clinical application of CT and CT-guided percutaneous transthoracic needle biopsy in patients with indeterminate pulmonary nodules*

    PubMed Central

    Cardoso, Luciana Vargas; Souza, Arthur Soares

    2014-01-01

    OBJECTIVE: To investigate the clinical application of CT and CT-guided percutaneous transthoracic needle biopsy (CT-PTNB) in patients with indeterminate pulmonary nodules (IPNs). METHODS: We retrospectively studied 113 patients with PNs undergoing CT and CT-PTNB. Variables such as gender, age at diagnosis, smoking status, CT findings, and CT-PTNB techniques were analyzed. Data analysis was performed with the Student's t-test for independent samples the chi-square test, and normal approximation test for comparison of two proportions. RESULTS: Of the 113 patients studied, 68 (60.2%) were male and 78 (69%) were smokers. The diameter of malignant lesions ranged from 2.6 cm to 10.0 cm. Most of the IPNs (85%) were located in the peripheral region. The biopsied IPNs were found to be malignant in 88 patients (77.8%) and benign in 25 (22.2%). Adenocarcinoma was the most common malignant tumor, affecting older patients. The IPN diameter was significantly greater in patients with malignant PNs than in those with benign IPNs (p < 0.001). Having regular contour correlated significantly with an IPN being benign (p = 0.022), whereas spiculated IPNs and bosselated IPNs were more often malignant (in 50.7% and 28.7%, respectively). Homogeneous attenuation and necrosis were more common in patients with malignant lesions (51.9% and 26.9%, respectively) CONCLUSIONS: In our sample, CT and CT-PTNB were useful in distinguishing between malignant and benign IPNs. Advanced age and smoking were significantly associated with malignancy. Certain CT findings related to IPNs (larger diameter, spiculated borders, homogeneous attenuation, and necrosis) were associated with malignancy. PMID:25210960

  2. Trabecular bone structure analysis in the osteoporotic spine using a clinical in vivo setup for 64-slice MDCT imaging: comparison to microCT imaging and microFE modeling.

    PubMed

    Issever, Ahi S; Link, Thomas M; Kentenich, Marie; Rogalla, Patrik; Schwieger, Karsten; Huber, Markus B; Burghardt, Andrew J; Majumdar, Sharmila; Diederichs, Gerd

    2009-09-01

    Assessment of trabecular microarchitecture may improve estimation of biomechanical strength, but visualization of trabecular bone structure in vivo is challenging. We tested the feasibility of assessing trabecular microarchitecture in the spine using multidetector CT (MDCT) on intact human cadavers in an experimental in vivo-like setup. BMD, bone structure (e.g., bone volume/total volume = BV/TV; trabecular thickness = Tb.Th; structure model index = SMI) and bone texture parameters were evaluated in 45 lumbar vertebral bodies using MDCT (mean in-plane pixel size, 274 microm(2); slice thickness, 500 microm). These measures were correlated with structure measures assessed with microCT at an isotropic spatial resolution of 16 microm and to microfinite element models (microFE) of apparent modulus and stiffness. MDCT-derived BMD and structure measures showed significant correlations to the density and structure obtained by microCT (BMD, R(2) = 0.86, p < 0.0001; BV/TV, R(2) = 0.64, p < 0.0001; Tb.Th, R(2) = 0.36, p < 0.01). When comparing microCT-derived measures with microFE models, the following correlations (p < 0.001) were found for apparent modulus and stiffness, respectively: BMD (R(2) = 0.58 and 0.66), BV/TV (R(2) = 0.44 and 0.58), and SMI (R(2) = 0.44 and 0.49). However, the overall highest correlation (p < 0.001) with microFE app. modulus (R(2) = 0.75) and stiffness (R(2) = 0.76) was achieved by the combination of QCT-derived BMD with the bone texture measure Minkowski Dimension. In summary, although still limited by its spatial resolution, trabecular bone structure assessment using MDCT is overall feasible. However, when comparing with microFE-derived bone properties, BMD is superior compared with single parameters for microarchitecture, and correlations further improve when combining with texture measures.

  3. Surface area and volume measurements of volcanic ash particles using micro-computed tomography (micro-CT): A comparison with scanning electron microscope (SEM) stereoscopic imaging and geometric considerations

    NASA Astrophysics Data System (ADS)

    Ersoy, Orkun; Şen, Erdal; Aydar, Erkan; Tatar, İlkan; Çelik, H. Hamdi

    2010-10-01

    Volcanic ash particles are important components of explosive eruptions, and their surface textures are the subject of intense research. Characterization of ash surfaces is crucial for understanding the physics of volcanic plumes, remote sensing measurements of ash and aerosols, interfacial processes, modelling transportation and deposition of tephra and characterizing eruptive styles. A number of different methods have been used over the years to arrive at surface area estimates. The more common methods include estimates based on geometric considerations (geometric surface area) and physisorption of gas molecules on the surface of interest (physical surface area). In this study, micro computed tomography (micro-CT), which is a non-destructive method providing three-dimensional data, enabled the measurement of surface area and volume of individual ash particles. Results were compared with the values obtained from SEM stereoscopic imaging and geometric considerations. Surface area estimates of micro-CT and SEM stereoscopic imaging are similar, with surface area/volume ratios (SA/V) of 0.0368 and 0.0467, respectively. Ash particle surface textures show a large deviation from that of simple geometric forms, and an approximation both to spheres and ellipsoids do not seem adequate for the representation of ash surface. SEM stereoscopic and/or micro-CT imaging are here suggested as good candidate techniques for the characterization of textures on macro-pore regions of ash particles.

  4. Standardized perfusion value: universal CT contrast enhancement scale that correlates with FDG PET in lung nodules.

    PubMed

    Miles, K A; Griffiths, M R; Fuentes, M A

    2001-08-01

    The standardized enhancement value and standardized perfusion value allow comparison between different methods for quantification of contrast enhancement during computed tomography (CT). Standard perfusion values calculated from CT measurements of perfusion within pulmonary nodules compared favorably with those derived from previously reported enhancement data and correlated with standardized uptake values obtained from positron emission tomographic images (r = 0.8, P <.01).

  5. [Comparative evaluation of ultrasonography, computerized tomography, angiography and lipiodol CT in defining extent of hepatocarcinoma. A multicenter study].

    PubMed

    Dalla Palma, L; Pozzi Mucelli, R; Sponza, M; Bartolozzi, C; De Santis, M; Gandini, G; Mannella, P; Matricardi, L; Rossi, C; Simonetti, G

    1995-03-01

    The authors report the results of a multicentric trial on hepatocellular carcinoma (HCC) patients, whose lesions were confirmed with biopsy or by high (> 400 ng/ml) alpha-fetoprotein levels. The series consisted of 149 patients examined in 8 different centers and submitted to ultrasonography (US), Computed Tomography (CT) before and after contrast agent administration, angiography and Lipiodol CT. According to lesion size and number, the patients were divided with each imaging modality into three groups: a) group 1: unifocal HCC < 5 cm diameter; b) group 2: multifocal HCC with 2-3 nodules and/or tumor mass < 80 ml; c) multifocal HCC with more than 3 nodules (with total tumor mass not exceeding 40% of liver volume) or with total tumor mass > 80 ml. In 77 patients all the examinations were available for comparison. US and CT diagnosed more patients as belonging to group 1 than angiography and Lipiodol CT, while more patients were classified as groups 2 and 3 with angiography and Lipiodol CT, meaning that US and CT may understage some HCC cases (about 15%) because they show a lower number of nodules. This observation was confirmed by the direct comparison between US and Lipiodol CT (in 114 patients), CT and Lipiodol CT (in 103 patients) and angiography and Lipiodol CT (in 116 patients). US and Lipiodol CT were in disagreement in 18 cases, CT and Lipiodol CT in 16 cases and angiography and Lipiodol CT in 13 cases. In most of these cases, Lipiodol CT showed more lesions than the other techniques. The size of the undetected lesions was small, ranging few mm to 2 cm in nearly all cases. To conclude, the results of this multicentric trial show that Lipiodol CT is a fundamental tool to evaluate HCC extent. In contrast, conventional CT appeared not to add any significant piece of information and can therefore be excluded from the diagnostic protocol of HCC.

  6. Comparison of Whole-Body 18F FDG PET/MR Imaging and Whole-Body 18F FDG PET/CT in Terms of Lesion Detection and Radiation Dose in Patients with Breast Cancer

    PubMed Central

    Melsaether, Amy N.; Raad, Roy A.; Pujara, Akshat C.; Ponzo, Fabio D.; Pysarenko, Kristine M.; Jhaveri, Komal; Babb, James S.; Sigmund, Eric E.; Kim, Sungheon G.; Moy, Linda A.

    2016-01-01

    Purpose To compare fluorine 18 (18F) fluorodeoxyglucose (FDG) combined positron emission tomography (PET) and magnetic resonance (MR) imaging with 18F FDG combined PET and computed tomography (CT) in terms of organ-specific metastatic lesion detection and radiation dose in patients with breast cancer. Materials and Methods From July 2012 to October 2013, this institutional review board–approved HIPAA-compliant prospective study included 51 patients with breast cancer (50 women; mean age, 56 years; range, 32–76 years; one man; aged 70 years) who completed PET/MR imaging with diffusion-weighted and contrast material–enhanced sequences after unenhanced PET/CT. Written informed consent for study participation was obtained. Two independent readers for each modality recorded site and number of lesions. Imaging and clinical follow-up, with consensus in two cases, served as the reference standard. Results There were 242 distant metastatic lesions in 30 patients, 18 breast cancers in 17 patients, and 19 positive axillary nodes in eight patients. On a per-patient basis, PET/MR imaging with diffusion-weighted and contrast-enhanced sequences depicted distant (30 of 30 [100%] for readers 1 and 2) and axillary (eight of eight [100%] for reader 1, seven of eight [88%] for reader 2) metastatic disease at rates similar to those of unenhanced PET/CT (distant metastatic disease: 28 of 29 [96%] for readers 3 and 4, P = .50; axillary metastatic disease: seven of eight [88%] for readers 3 and 4, P > .99) and outperformed PET/CT in the detection of breast cancer (17 of 17 [100%] for readers 1 and 2 vs 11 of 17 [65%] for reader 3 and 10 of 17 [59%] for reader 4; P < .001). PET/MR imaging showed increased sensitivity for liver (40 of 40 [100%] for reader 1 and 32 of 40 [80%] for reader 2 vs 30 of 40 [75%] for reader 3 and 28 of 40 [70%] for reader 4; P < .001) and bone (105 of 107 [98%] for reader 1 and 102 of 107 [95%] for reader 2 vs 106 of 107 [99%] for reader 3 and 93 of 107 [87

  7. Investigating CT to CBCT image registration for head and neck proton therapy as a tool for daily dose recalculation

    SciTech Connect

    Landry, Guillaume; Nijhuis, Reinoud; Thieke, Christian; Reiner, Michael; Ganswindt, Ute; Belka, Claus; Dedes, George; Handrack, Josefine; Parodi, Katia; Janssens, Guillaume; Orban de Xivry, Jonathan; Kamp, Florian; Wilkens, Jan J.; Paganelli, Chiara; Riboldi, Marco; Baroni, Guido

    2015-03-15

    Purpose: Intensity modulated proton therapy (IMPT) of head and neck (H and N) cancer patients may be improved by plan adaptation. The decision to adapt the treatment plan based on a dose recalculation on the current anatomy requires a diagnostic quality computed tomography (CT) scan of the patient. As gantry-mounted cone beam CT (CBCT) scanners are currently being offered by vendors, they may offer daily or weekly updates of patient anatomy. CBCT image quality may not be sufficient for accurate proton dose calculation and it is likely necessary to perform CBCT CT number correction. In this work, the authors investigated deformable image registration (DIR) of the planning CT (pCT) to the CBCT to generate a virtual CT (vCT) to be used for proton dose recalculation. Methods: Datasets of six H and N cancer patients undergoing photon intensity modulated radiation therapy were used in this study to validate the vCT approach. Each dataset contained a CBCT acquired within 3 days of a replanning CT (rpCT), in addition to a pCT. The pCT and rpCT were delineated by a physician. A Morphons algorithm was employed in this work to perform DIR of the pCT to CBCT following a rigid registration of the two images. The contours from the pCT were deformed using the vector field resulting from DIR to yield a contoured vCT. The DIR accuracy was evaluated with a scale invariant feature transform (SIFT) algorithm comparing automatically identified matching features between vCT and CBCT. The rpCT was used as reference for evaluation of the vCT. The vCT and rpCT CT numbers were converted to stopping power ratio and the water equivalent thickness (WET) was calculated. IMPT dose distributions from treatment plans optimized on the pCT were recalculated with a Monte Carlo algorithm on the rpCT and vCT for comparison in terms of gamma index, dose volume histogram (DVH) statistics as well as proton range. The DIR generated contours on the vCT were compared to physician-drawn contours on the rpCT

  8. Surface area and volume measurements of volcanic ash particles using micro-computed tomography (micro-CT): A comparison with scanning electron microscope (SEM) stereoscopic imaging and Brunauer-Emmett-Teller (BET) model

    NASA Astrophysics Data System (ADS)

    Ersoy, Orkun; Şen, Erdal; Aydar, Erkan; Tatar, Ä.°Lkan; Ćelik, H. Hamdi

    2010-05-01

    Volcanic ash particles are important components of explosive eruptions and their surface texture is the subject of intense research. Characterization of ash surfaces is crucial for understanding the physics of the volcanic plumes, remote sensing measurements of ash and aerosols, interfacial processes, modelling transportation and deposition of tephra and characterizing eruptive styles. A number of different methods have been used over the years to arrive at surface area estimates. The more common methods include estimates based on the geometric considerations (geometric surface area) and the physisorption of gas molecules on the surface of interest (physical surface area). In this study, micro computed tomography (micro-CT), a non-destructive method providing three-dimensional data enabled the measurement of surface areas and volumes of individual ash particles. Specific surface area estimates for ash particles were also obtained using nitrogen as gas adsorbent and the BET (Brunauer-Emmett-Teller) model. Results were compared with the values obtained from SEM stereoscopic imaging and geometric considerations. Surface area estimates of micro-CT and SEM stereoscopic imaging overlaps with mean specific surface area results of 0.0167 and 0.0214 m2/g, respectively. However, ash particle surface textures present quite a deviation from that of their geometric forms and approximation to sphere and ellipsoid both seemed to be inadequate for representation of real ash surfaces. The higher surface area estimate (> 0.4 m2/g) obtained from the technique based on physical sorption of gases (BET model here) was attributed to its capability for surface areas associated even with angstrom-sized pores. SEM stereoscopic and/or micro-CT imaging were suggested for characterization of textures on macro-pore regions of ash particles.

  9. Comparison of point-of-care-compatible lysis methods for bacteria and viruses.

    PubMed

    Heiniger, Erin K; Buser, Joshua R; Mireles, Lillian; Zhang, Xiaohong; Ladd, Paula D; Lutz, Barry R; Yager, Paul

    2016-09-01

    Nucleic acid sample preparation has been an especially challenging barrier to point-of-care nucleic acid amplification tests in low-resource settings. Here we provide a head-to-head comparison of methods for lysis of, and nucleic acid release from, several pathogenic bacteria and viruses-methods that are adaptable to point-of-care usage in low-resource settings. Digestion with achromopeptidase, a mixture of proteases and peptidoglycan-specific hydrolases, followed by thermal deactivation in a boiling water bath, effectively released amplifiable nucleic acid from Staphylococcus aureus, Bordetella pertussis, respiratory syncytial virus, and influenza virus. Achromopeptidase was functional after dehydration and reconstitution, even after eleven months of dry storage without refrigeration. Mechanical lysis methods proved to be effective against a hard-to-lyse Mycobacterium species, and a miniature bead-mill, the AudioLyse, is shown to be capable of releasing amplifiable DNA and RNA from this species. We conclude that point-of-care-compatible sample preparation methods for nucleic acid tests need not introduce amplification inhibitors, and can provide amplification-ready lysates from a wide range of bacterial and viral pathogens.

  10. Efficacy of biological agents administered as monotherapy in rheumatoid arthritis: a Bayesian mixed-treatment comparison analysis

    PubMed Central

    Migliore, Alberto; Bizzi, Emanuele; Egan, Colin Gerard; Bernardi, Mauro; Petrella, Lea

    2015-01-01

    Background Biological agents provide an important therapeutic alternative for rheumatoid arthritis patients refractory to conventional disease-modifying antirheumatic drugs. Few head-to-head comparative trials are available. Purpose The aim of this meta-analysis was to compare the relative efficacy of different biologic agents indicated for use as monotherapy in rheumatoid arthritis. Methods A systemic literature search was performed on electronic databases to identify articles reporting double-blind randomized controlled trials investigating the efficacy of biologic agents indicated for monotherapy. Efficacy was assessed using American College of Rheumatology (ACR) 20, 50, and 70 criteria at 16–24 weeks. Relative efficacy was estimated using Bayesian mixed-treatment comparison models. Outcome measures were expressed as odds ratio and 95% credible intervals. Results Ten randomized controlled trials were selected for data extraction and analysis. Mixed-treatment comparison analysis revealed that tocilizumab offered 100% probability of being the best treatment for inducing an ACR20 response versus placebo, methotrexate, adalimumab, or etanercept. Likewise, for ACR50 and ACR70 outcome responses, tocilizumab had a 99.8% or 98.7% probability of being the best treatment, respectively, compared to other treatments or placebo. Tocilizumab increased the relative probability of being the best treatment (vs methotrexate) by 3.2-fold (odds ratio: 2.1–3.89) for all ACR outcomes. Conclusion Tocilizumab offered the greatest possibility of obtaining an ACR20, ACR50, and ACR70 outcome vs other monotherapies or placebo. PMID:26366085

  11. Expression of cancer testis antigen CT45 in classical Hodgkin lymphoma and other B-cell lymphomas.

    PubMed

    Chen, Yao-Tseng; Chadburn, Amy; Lee, Peishan; Hsu, Melinda; Ritter, Erika; Chiu, April; Gnjatic, Sacha; Pfreundschuh, Michael; Knowles, Daniel M; Old, Lloyd J

    2010-02-16

    We have shown previously that cancer/testis (CT) antigen, CT45, is expressed in various epithelial cancers at a frequency of <5% to approximately 35%. In this study, the protein expression of CT45 was examined in non-Hodgkin B-cell lymphomas and classical Hodgkin lymphoma by immunohistochemical analysis. Serological response to CT45 was also evaluated by ELISA using CT45 recombinant protein and sera from patients with Hodgkin lymphoma. None of the 80 low-grade B-cell lymphomas, including chronic lymphocytic leukemia/small lymphocytic lymphoma, follicular lymphoma, and mantle cell lymphoma, expressed CT45. In comparison, CT45 was expressed in 28 of 126 (22%) diffuse large B-cell lymphomas (DLBCL). A remarkably high percentage (42/72, 58%) of classical Hodgkin lymphoma contained CT45-positive Reed-Sternberg cells. Nodular sclerosis and mixed-cellularity subtypes had similar frequency of CT45 expression, but most EBV-positive cases were CT45 negative. Gray-zone lymphoma (cases with features of both DLBCL and classical Hodgkin lymphoma) also showed frequent (64%) CT45 expression. Evaluation of reactive lymphoid tissues showed scattered CT45-positive lymphocytes in a single case of florid follicular hyperplasia, raising the possibility that this case was an evolving malignancy. Despite frequent CT45 expression, only 1 of 67 Hodgkin lymphoma patients had detectable anti-CT45 antibodies in the serum, suggesting that the immune response to CT45 may be suppressed. In conclusion, classical Hodgkin lymphoma has the highest frequency of CT45 expression among all malignancies tested to date, the frequency of CT45 expression in DLBCL is similar to that seen in epithelial cancers, and low-grade non-Hodgkin B-cell lymphomas do not express CT45.

  12. Chronic osteomyelitis examined by CT

    SciTech Connect

    Wing, V.W.; Jeffrey, R.B. Jr.; Federle, M.P.; Helms, C.A.; Trafton, P.

    1985-01-01

    CT examination of 25 patients who had acute exacerbations of chronic osteomyelitis allowed for the correct identification of single or multiple sequestra in 14 surgical patients. Plain radiographs were equivocal for sequestra in seven of these patients, because the sequestra were too small or because diffuse bony sclerosis was present. CT also demonstrated a foreign body and five soft tissue abscesses not suspected on the basis of plain radiographs. CT studies, which helped guide the operative approach, were also useful in treating those patients whose plain radiographs were positive for sequestra. The authors review the potential role of CT in evaluating patients with chronic osteomyelitis.

  13. Comparison of Two Accelerators for Monte Carlo Radiation Transport Calculations, NVIDIA Tesla M2090 GPU and Intel Xeon Phi 5110p Coprocessor: A Case Study for X-ray CT Imaging Dose Calculation

    NASA Astrophysics Data System (ADS)

    Liu, Tianyu; Xu, X. George; Carothers, Christopher D.

    2014-06-01

    Hardware accelerators are currently becoming increasingly important in boosting high performance computing sys- tems. In this study, we tested the performance of two accelerator models, NVIDIA Tesla M2090 GPU and Intel Xeon Phi 5110p coprocessor, using a new Monte Carlo photon transport package called ARCHER-CT we have developed for fast CT imaging dose calculation. The package contains three code variants, ARCHER - CTCPU, ARCHER - CTGPU and ARCHER - CTCOP to run in parallel on the multi-core CPU, GPU and coprocessor architectures respectively. A detailed GE LightSpeed Multi-Detector Computed Tomography (MDCT) scanner model and a family of voxel patient phantoms were included in the code to calculate absorbed dose to radiosensitive organs under specified scan protocols. The results from ARCHER agreed well with those from the production code Monte Carlo N-Particle eXtended (MCNPX). It was found that all the code variants were significantly faster than the parallel MCNPX running on 12 MPI processes, and that the GPU and coprocessor performed equally well, being 2.89~4.49 and 3.01~3.23 times faster than the parallel ARCHER - CTCPU running with 12 hyperthreads.

  14. A comparison of 3D poly(ε-caprolactone) tissue engineering scaffolds produced with conventional and additive manufacturing techniques by means of quantitative analysis of SR μ-CT images

    NASA Astrophysics Data System (ADS)

    Brun, F.; Intranuovo, F.; Mohammadi, S.; Domingos, M.; Favia, P.; Tromba, G.

    2013-07-01

    The technique used to produce a 3D tissue engineering (TE) scaffold is of fundamental importance in order to guarantee its proper morphological characteristics. An accurate assessment of the resulting structural properties is therefore crucial in order to evaluate the effectiveness of the produced scaffold. Synchrotron radiation (SR) computed microtomography (μ-CT) combined with further image analysis seems to be one of the most effective techniques to this aim. However, a quantitative assessment of the morphological parameters directly from the reconstructed images is a non trivial task. This study considers two different poly(ε-caprolactone) (PCL) scaffolds fabricated with a conventional technique (Solvent Casting Particulate Leaching, SCPL) and an additive manufacturing (AM) technique (BioCell Printing), respectively. With the first technique it is possible to produce scaffolds with random, non-regular, rounded pore geometry. The AM technique instead is able to produce scaffolds with square-shaped interconnected pores of regular dimension. Therefore, the final morphology of the AM scaffolds can be predicted and the resulting model can be used for the validation of the applied imaging and image analysis protocols. It is here reported a SR μ-CT image analysis approach that is able to effectively and accurately reveal the differences in the pore- and throat-size distributions as well as connectivity of both AM and SCPL scaffolds.

  15. Comparison of the cobas 4800 CT/NG Test with Culture for Detecting Neisseria gonorrhoeae in Genital and Nongenital Specimens in a Low-Prevalence Population in New Zealand

    PubMed Central

    Miller, Amanda; Jones, Mark; Whiley, David

    2013-01-01

    To assess the clinical utility of replacing microbial culture for Neisseria gonorrhoeae with a nucleic acid amplification test (NAAT), we compared N. gonorrhoeae culture with the cobas 4800 CT/NG test for 18,247 urogenital and 666 nongenital samples. For urogenital specimens, the sensitivity, specificity, and positive and negative predictive values of the cobas N. gonorrhoeae PCR were 98.7%, 100%, 95.6%, and 100%, respectively, and for nongenital specimens, the values were 100%, 99.8%, 92.9%, and 100%, respectively. In our test population, 37% (10,185) of patients tested over the study period were screened for C. trachomatis by PCR but were not screened for gonorrhea by culture. Of these, 43 were N. gonorrhoeae positive by PCR and therefore went undiagnosed. The cobas 4800 CT/NG test diagnosed 33% (n = 30) more urogenital and 25% (n = 3) more rectal gonorrhea infections than culture and, based on the above performance indicators, does not require supplementary testing for urogenital or rectal specimens. The ability to test noninvasive specimens (such as urine and self-taken vulvovaginal swabs) for N. gonorrhoeae will enable more patients to be screened for infection, thus offering significant positive public health benefits. PMID:23467604

  16. Analysis of patient CT dose data using virtualdose

    NASA Astrophysics Data System (ADS)

    Bennett, Richard

    X-ray computer tomography has many benefits to medical and research applications. Recently, over the last decade CT has had a large increase in usage in hospitals and medical diagnosis. In pediatric care, from 2000 to 2006, abdominal CT scans increased by 49 % and chest CT by 425 % in the emergency room (Broder 2007). Enormous amounts of effort have been performed across multiple academic and government groups to determine an accurate measure of organ dose to patients who undergo a CT scan due to the inherent risks with ionizing radiation. Considering these intrinsic risks, CT dose estimating software becomes a necessary tool that health care providers and radiologist must use to determine many metrics to base the risks versus rewards of having an x-ray CT scan. This thesis models the resultant organ dose as body mass increases for patients with all other related scan parameters fixed. In addition to this,this thesis compares a modern dose estimating software, VirtualDose CT to two other programs, CT-Expo and ImPACT CT. The comparison shows how the software's theoretical basis and the phantom they use to represent the human body affect the range of results in organ dose. CT-Expo and ImPACT CT dose estimating software uses a different model for anatomical representation of the organs in the human body and the results show how that approach dramatically changes the outcome. The results categorizes four datasets as compared to the three software types where the appropriate phantom was available. Modeling was done to simulate chest abdominal pelvis scans and whole body scans. Organ dose difference versus body mass index shows as body mass index (BMI) ranges from 23.5 kg/m 2 to 45 kg/m2 the amount of organ dose also trends a percent change from -4.58 to -176.19 %. Comparing organ dose difference with increasing x-ray tube potential from 120 kVp to 140 kVp the percent change in organ dose increases from 55 % to 65 % across all phantoms. In comparing VirtualDose to CT

  17. Crystal Structures of Xanthomonas campestris OleA Reveal Features That Promote Head-to-Head Condensation of Two Long-Chain Fatty Acids

    SciTech Connect

    Goblirsch, BR; Frias, JA; Wackett, LP; Wilmot, CM

    2012-05-22

    OleA is a thiolase superfamily enzyme that has been shown to catalyze the condensation of two long-chain fatty acylcoenzyme A (CoA) substrates. The enzyme is part of a larger gene cluster responsible for generating long-chain olefin products, a potential biofuel precursor. In thiolase superfamily enzymes, catalysis is achieved via a ping-pong mechanism. The first substrate forms a covalent intermediate with an active site cysteine that is followed by reaction with the second substrate. For OleA, this conjugation proceeds by a nondecarboxylative Claisen condensation. The OleA from Xanthomonas campestris has been crystallized and its structure determined, along with inhibitor-bound and xenon-derivatized structures, to improve our understanding of substrate positioning in the context of enzyme turnover. OleA is the first characterized thiolase superfamily member that has two long-chain alkyl substrates that need to be bound simultaneously and therefore uniquely requires an additional alkyl binding channel. The location of the fatty acid biosynthesis inhibitor, cerulenin, that possesses an alkyl chain length in the range of known OleA substrates, in conjunction with a single xenon binding site, leads to the putative assignment of this novel alkyl binding channel. Structural overlays between the OleA homologues, 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase and the fatty acid biosynthesis enzyme FabH, allow assignment of the two remaining channels: one for the thioester-containing pantetheinate arm and the second for the alkyl group of one substrate. A short beta-hairpin region is ordered in only one of the crystal forms, and that may suggest open and closed states relevant for substrate binding. Cys143 is the conserved catalytic cysteine within the superfamily, and the site of alkylation by cerulenin. The alkylated structure suggests that a glutamic acid residue (Glu117 beta) likely promotes Claisen condensation by acting as the catalytic base. Unexpectedly, Glu117 beta comes from the other monomer of the physiological dimer.

  18. Crystal Structures of Xanthomonas campestris OleA Reveal Features That Promote Head-to-Head Condensation of Two Long-Chain Fatty Acids

    SciTech Connect

    Goblirsch, Brandon R.; Frias, Janice A.; Wackett, Lawrence P.; Wilmot, Carrie M.

    2012-10-25

    OleA is a thiolase superfamily enzyme that has been shown to catalyze the condensation of two long-chain fatty acyl-coenzyme A (CoA) substrates. The enzyme is part of a larger gene cluster responsible for generating long-chain olefin products, a potential biofuel precursor. In thiolase superfamily enzymes, catalysis is achieved via a ping-pong mechanism. The first substrate forms a covalent intermediate with an active site cysteine that is followed by reaction with the second substrate. For OleA, this conjugation proceeds by a nondecarboxylative Claisen condensation. The OleA from Xanthomonas campestris has been crystallized and its structure determined, along with inhibitor-bound and xenon-derivatized structures, to improve our understanding of substrate positioning in the context of enzyme turnover. OleA is the first characterized thiolase superfamily member that has two long-chain alkyl substrates that need to be bound simultaneously and therefore uniquely requires an additional alkyl binding channel. The location of the fatty acid biosynthesis inhibitor, cerulenin, that possesses an alkyl chain length in the range of known OleA substrates, in conjunction with a single xenon binding site, leads to the putative assignment of this novel alkyl binding channel. Structural overlays between the OleA homologues, 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase and the fatty acid biosynthesis enzyme FabH, allow assignment of the two remaining channels: one for the thioester-containing pantetheinate arm and the second for the alkyl group of one substrate. A short {beta}-hairpin region is ordered in only one of the crystal forms, and that may suggest open and closed states relevant for substrate binding. Cys143 is the conserved catalytic cysteine within the superfamily, and the site of alkylation by cerulenin. The alkylated structure suggests that a glutamic acid residue (Glu117{beta}) likely promotes Claisen condensation by acting as the catalytic base. Unexpectedly, Glu117{beta} comes from the other monomer of the physiological dimer.

  19. Prospective, Head-to-Head Study of Three Computerized Neurocognitive Assessment Tools (CNTs): Reliability and Validity for the Assessment of Sport-Related Concussion.

    PubMed

    Nelson, Lindsay D; LaRoche, Ashley A; Pfaller, Adam Y; Lerner, E Brooke; Hammeke, Thomas A; Randolph, Christopher; Barr, William B; Guskiewicz, Kevin; McCrea, Michael A

    2016-01-01

    Limited data exist comparing the performance of computerized neurocognitive tests (CNTs) for assessing sport-related concussion. We evaluated the reliability and validity of three CNTs-ANAM, Axon Sports/Cogstate Sport, and ImPACT-in a common sample. High school and collegiate athletes completed two CNTs each at baseline. Concussed (n=165) and matched non-injured control (n=166) subjects repeated testing within 24 hr and at 8, 15, and 45 days post-injury. Roughly a quarter of each CNT's indices had stability coefficients (M=198 day interval) over .70. Group differences in performance were mostly moderate to large at 24 hr and small by day 8. The sensitivity of reliable change indices (RCIs) was best at 24 hr (67.8%, 60.3%, and 47.6% with one or more significant RCIs for ImPACT, Axon, and ANAM, respectively) but diminished to near the false positive rates thereafter. Across time, the CNTs' sensitivities were highest in those athletes who became asymptomatic within 1 day before neurocognitive testing but was similar to the tests' false positive rates when including athletes who became asymptomatic several days earlier. Test-retest reliability was similar among these three CNTs and below optimal standards for clinical use on many subtests. Analyses of group effect sizes, discrimination, and sensitivity and specificity suggested that the CNTs may add incrementally (beyond symptom scores) to the identification of clinical impairment within 24 hr of injury or within a short time period after symptom resolution but do not add significant value over symptom assessment later. The rapid clinical recovery course from concussion and modest stability probably jointly contribute to limited signal detection capabilities of neurocognitive tests outside a brief post-injury window. (JINS, 2016, 22, 24-37).

  20. Treatment Selection Choices Should Not Be Based on Benefits or Costs Alone: A Head-to-Head Randomized Controlled Trial of Antiviral Drugs for Hepatitis C

    PubMed Central

    Davitkov, Perica; Chandar, Apoorva Krishna; Hirsch, Amy; Compan, Anita; Silveira, Marina G.; Anthony, Donald D.; Smith, Suzanne; Gideon, Clare; Bonomo, Robert A.; Falck-Ytter, Yngve

    2016-01-01

    Background Clinicians often face dilemmas with decisions related to formulary choices when two similar drugs are simultaneously available in the market. We studied the comparative safety, effectiveness, and treatment costs of the two first generation direct-acting antiviral agents (DAA), boceprevir and telaprevir as uncertainty existed regarding the drug of choice between these two seemingly equally Hepatitis-C treatment options. Methods We randomly assigned 50 patients in an open-label, pragmatic randomized controlled trial (RCT) at a VA Medical Center to either boceprevir or telaprevir in combination with peginterferon and ribavirin, stratified by the presence of cirrhosis and prior treatment experience. Tolerability was assessed at each visit and reasons for discontinuation of treatment and severity of adverse events due to PI treatment were adjudicated using a blinded adjudication committee. The primary outcome was difference in tolerability between boceprevir vs. telaprevir. Secondary outcomes included viral response rates and cost-per cure achieved. Results Higher rates of treatment discontinuations and/or severe DAA associated adverse events were seen in 10/25 (40%) patients randomized to telaprevir compared to 2/25 (8%) patients randomized to boceprevir (RR: 5; 95% CI: 1.2, 20; p<0.01). Cure rates did not appear to be significantly different between groups (telaprevir vs. boceprevir: RR 1.23; 95% CI: 0.76, 1.99; p = 0.39). On an intention-to-treat basis, total cost per cure was $44,329 for boceprevir vs. $57,115 for telaprevir. The significant side effect profile of telaprevir combined with the availability of highly efficacious second generation DAAs led to the early discontinuation of the trial. Conclusion Telaprevir is associated with a significantly higher rate of severe adverse events leading to treatment discontinuations, hospitalizations or severe anemia and a substantially higher cost per SVR when compared to boceprevir. Real-time, point of care, pragmatic randomized controlled trials are necessary for guidance beyond just acquisition costs and to make evidence-based formulary selections when multiple effective treatments are available. (Clinicaltrials.gov registration: NCT02113631). PMID:27741230

  1. Cage matching: head to head competition experiments of an invasive plant species from different regions as a means to test for differentiation.

    PubMed

    Lortie, Christopher J; Munshaw, Michael; Zikovitz, Andrea; Hierro, Jose

    2009-01-01

    Many hypotheses are prevalent in the literature predicting why some plant species can become invasive. However, in some respects, we lack a standard approach to compare the breadth of various studies and differentiate between alternative explanations. Furthermore, most of these hypotheses rely on 'changes in density' of an introduced species to infer invasiveness. Here, we propose a simple method to screen invasive plant species for potential differences in density effects between novel regions. Studies of plant competition using density series are a fundamental tool applied to virtually every aspect of plant population ecology to better understand evolution. Hence, we use a simple density series with substitution contrasting the performance of Centaurea solstitialis in monoculture (from one region) to mixtures (seeds from two regions). All else being equal, if there is no difference between the introduced species in the two novel regions compared, Argentina and California, then there should be no competitive differences between intra and inter-regional competition series. Using a replicated regression design, seeds of each species were sown in the greenhouse at 5 densities in monoculture and mixed and grown till onset of flowering. Centaurea seeds from California had higher germination while seedlings had significantly greater survival than Argentina. There was no evidence for density dependence in any measure for the California region but negative density dependence was detected in the germination of seeds from Argentina. The relative differences in competition also differed between regions with no evidence of differential competitive effects of seeds from Argentina in mixture versus monoculture while seeds from California expressed a relative cost in germination and relative growth rate in mixtures with Argentina. In the former instance, lack of difference does not mean 'no ecological differences' but does suggest that local adaptation in competitive abilities has not occurred. Importantly, this method successfully detected differences in the response of an invasive species to changes in density between novel regions which suggests that it is a useful preliminary means to explore invasiveness.

  2. Cage Matching: Head to Head Competition Experiments of an Invasive Plant Species from Different Regions as a Means to Test for Differentiation

    PubMed Central

    Lortie, Christopher J.; Munshaw, Michael; Zikovitz, Andrea; Hierro, Jose

    2009-01-01

    Many hypotheses are prevalent in the literature predicting why some plant species can become invasive. However, in some respects, we lack a standard approach to compare the breadth of various studies and differentiate between alternative explanations. Furthermore, most of these hypotheses rely on ‘changes in density’ of an introduced species to infer invasiveness. Here, we propose a simple method to screen invasive plant species for potential differences in density effects between novel regions. Studies of plant competition using density series are a fundamental tool applied to virtually every aspect of plant population ecology to better understand evolution. Hence, we use a simple density series with substitution contrasting the performance of Centaurea solstitialis in monoculture (from one region) to mixtures (seeds from two regions). All else being equal, if there is no difference between the introduced species in the two novel regions compared, Argentina and California, then there should be no competitive differences between intra and inter-regional competition series. Using a replicated regression design, seeds of each species were sown in the greenhouse at 5 densities in monoculture and mixed and grown till onset of flowering. Centaurea seeds from California had higher germination while seedlings had significantly greater survival than Argentina. There was no evidence for density dependence in any measure for the California region but negative density dependence was detected in the germination of seeds from Argentina. The relative differences in competition also differed between regions with no evidence of differential competitive effects of seeds from Argentina in mixture versus monoculture while seeds from California expressed a relative cost in germination and relative growth rate in mixtures with Argentina. In the former instance, lack of difference does not mean ‘no ecological differences’ but does suggest that local adaptation in competitive abilities has not occurred. Importantly, this method successfully detected differences in the response of an invasive species to changes in density between novel regions which suggests that it is a useful preliminary means to explore invasiveness. PMID:19283070

  3. Prospective, Head-to-Head Study of Three Computerized Neurocognitive Assessment Tools (CNTs): Reliability and Validity for the Assessment of Sport-Related Concussion

    PubMed Central

    Nelson, Lindsay D.; LaRoche, Ashley A.; Pfaller, Adam Y.; Lerner, E. Brooke; Hammeke, Thomas A.; Randolph, Christopher; Barr, William B.; Guskiewicz, Kevin; McCrea, Michael A.

    2016-01-01

    Limited data exist comparing the performance of computerized neurocognitive tests (CNTs) for assessing sport-related concussion. We evaluated the reliability and validity of three CNTs—ANAM, Axon Sports/Cogstate Sport, and ImPACT—in a common sample. High school and collegiate athletes completed two CNTs each at baseline. Concussed (n = 165) and matched non-injured control (n = 166) subjects repeated testing within 24 hr and at 8, 15, and 45 days post-injury. Roughly a quarter of each CNT's indices had stability coefficients (M = 198 day interval) over .70. Group differences in performance were mostly moderate to large at 24 hr and small by day 8. The sensitivity of reliable change indices (RCIs) was best at 24 hr (67.8%, 60.3%, and 47.6% with one or more significant RCIs for ImPACT, Axon, and ANAM, respectively) but diminished to near the false positive rates thereafter. Across time, the CNTs' sensitivities were highest in those athletes who became asymptomatic within 1 day before neurocognitive testing but was similar to the tests' false positive rates when including athletes who became asymptomatic several days earlier. Test–retest reliability was similar among these three CNTs and below optimal standards for clinical use on many subtests. Analyses of group effect sizes, discrimination, and sensitivity and specificity suggested that the CNTs may add incrementally (beyond symptom scores) to the identification of clinical impairment within 24 hr of injury or within a short time period after symptom resolution but do not add significant value over symptom assessment later. The rapid clinical recovery course from concussion and modest stability probably jointly contribute to limited signal detection capabilities of neurocognitive tests outside a brief post-injury window. PMID:26714883

  4. An Independent, Prospective, Head to Head Study of the Reliability and Validity of Neurocognitive Test Batteries for the Assessment of Mild Traumatic Brain Injury

    DTIC Science & Technology

    2013-03-01

    to Head Study of the Reliability and Validity of Neurocognitive Test Batteries for the Assessment of Mild Traumatic Brain Injury PRINCIPAL...CONTRACT NUMBER Validity of Neurocognitive Test Batteries for the Assessment of Mild Traumatic Brain Injury 5b. GRANT NUMBER W81XWH-12-1...tools (NCAT’s) for the acute neurocognitive assessment, tracking cognitive recovery, and informing clinical management after mild traumatic brain injury

  5. Cloning, purification, crystallization and preliminary X-ray diffraction of the OleC protein from Stenotrophomonas maltophilia involved in head-to-head hydrocarbon biosynthesis

    SciTech Connect

    Frias, JA; Goblirsch, BR; Wackett, LP; Wilmot, CM

    2010-08-28

    OleC, a biosynthetic enzyme involved in microbial hydrocarbon biosynthesis, has been crystallized. Synchrotron X-ray diffraction data have been collected to 3.4 A resolution. The crystals belonged to space group P3(1)21 or P3(2)21, with unit-cell parameters a = b = 98.8, c = 141.0 A.

  6. Evaluation of CT-based SUV normalization

    NASA Astrophysics Data System (ADS)

    Devriese, Joke; Beels, Laurence; Maes, Alex; Van de Wiele, Christophe; Pottel, Hans

    2016-09-01

    The purpose of this study was to determine patients’ lean body mass (LBM) and lean tissue (LT) mass using a computed tomography (CT)-based method, and to compare standardized uptake value (SUV) normalized by these parameters to conventionally normalized SUVs. Head-to-toe positron emission tomography (PET)/CT examinations were retrospectively retrieved and semi-automatically segmented into tissue types based on thresholding of CT Hounsfield units (HU). The following HU ranges were used for determination of CT-estimated LBM and LT (LBMCT and LTCT):  -180 to  -7 for adipose tissue (AT), -6 to 142 for LT, and 143 to 3010 for bone tissue (BT). Formula-estimated LBMs were calculated using formulas of James (1976 Research on Obesity: a Report of the DHSS/MRC Group (London: HMSO)) and Janmahasatian et al (2005 Clin. Pharmacokinet. 44 1051-65), and body surface area (BSA) was calculated using the DuBois formula (Dubois and Dubois 1989 Nutrition 5 303-11). The CT segmentation method was validated by comparing total patient body weight (BW) to CT-estimated BW (BWCT). LBMCT was compared to formula-based estimates (LBMJames and LBMJanma). SUVs in two healthy reference tissues, liver and mediastinum, were normalized for the aforementioned parameters and compared to each other in terms of variability and dependence on normalization factors and BW. Comparison of actual BW to BWCT shows a non-significant difference of 0.8 kg. LBMJames estimates are significantly higher than LBMJanma with differences of 4.7 kg for female and 1.0 kg for male patients. Formula-based LBM estimates do not significantly differ from LBMCT, neither for men nor for women. The coefficient of variation (CV) of SUV normalized for LBMJames (SUVLBM-James) (12.3%) was significantly reduced in liver compared to SUVBW (15.4%). All SUV variances in mediastinum were significantly reduced (CVs were 11.1-12.2%) compared to SUVBW (15.5%), except SUVBSA (15.2%). Only SUVBW and SUVLBM-James show

  7. Comparative evaluation of target volumes defined by deformable and rigid registration of diagnostic PET/CT to planning CT in primary esophageal cancer

    PubMed Central

    Guo, Yanluan; Li, Jianbin; Zhang, Peng; Shao, Qian; Xu, Min; Li, Yankang

    2017-01-01

    Abstract Background: To evaluate the geometrical differences of target volumes propagated by deformable image registration (DIR) and rigid image registration (RIR) to assist target volume delineation between diagnostic Positron emission tomography/computed tomography (PET/CT) and planning CT for primary esophageal cancer (EC). Methods: Twenty-five patients with EC sequentially underwent a diagnostic 18F-fluorodeoxyglucose (18F-FDG) PET/CT scan and planning CT simulation. Only 19 patients with maximum standardized uptake value (SUVmax) ≥ 2.0 of the primary volume were available. Gross tumor volumes (GTVs) were delineated using CT and PET display settings. The PET/CT images were then registered with planning CT using MIM software. Subsequently, the PET and CT contours were propagated by RIR and DIR to planning CT. The properties of these volumes were compared. Results: When GTVCT delineated on CT of PET/CT after both RIR and DIR was compared with GTV contoured on planning CT, significant improvements using DIR were observed in the volume, displacements of the center of mass (COM) in the 3-dimensional (3D) direction, and Dice similarity coefficient (DSC) (P = 0.003; 0.006; 0.014). Although similar improvements were not observed for the same comparison using DIR for propagated PET contours from diagnostic PET/CT to planning CT (P > 0.05), for DSC and displacements of COM in the 3D direction of PET contours, the DIR resulted in the improved volume of a large percentage of patients (73.7%; 68.45%; 63.2%) compared with RIR. For diagnostic CT-based contours or PET contours at SUV2.5 propagated by DIR with planning CT, the DSC and displacements of COM in 3D directions in the distal segment were significantly improved compared to the upper and middle segments (P > 0.05). Conclusion: We observed a trend that deformable registration might improve the overlap for gross target volumes from diagnostic PET/CT to planning CT. The distal EC might benefit more from DIR

  8. Estimating radiation risk induced by CT screening for Korean population

    NASA Astrophysics Data System (ADS)

    Yang, Won Seok; Yang, Hye Jeong; Min, Byung In

    2017-02-01

    The purposes of this study are to estimate the radiation risks induced by chest/abdomen computed tomography (CT) screening for healthcare and to determine the cancer risk level of the Korean population compared to other populations. We used an ImPACT CT Patient Dosimetry Calculator to compute the organ effective dose induced by CT screening (chest, low-dose chest, abdomen/pelvis, and chest/abdomen/pelvis CT). A risk model was applied using principles based on the BEIR VII Report in order to estimate the lifetime attributable risk (LAR) using the Korean Life Table 2010. In addition, several countries including Hong Kong, the United States (U.S.), and the United Kingdom, were selected for comparison. Herein, each population exposed radiation dose of 100 mSv was classified according to country, gender and age. For each CT screening the total organ effective dose calculated by ImPACT was 6.2, 1.5, 5.2 and 11.4 mSv, respectively. In the case of Korean female LAR, it was similar to Hong Kong female but lower than those of U.S. and U.K. females, except for those in their twenties. The LAR of Korean males was the highest for all types of CT screening. However, the difference of the risk level was negligible because of the quite low value.

  9. Automated lung segmentation of low resolution CT scans of rats

    NASA Astrophysics Data System (ADS)

    Rizzo, Benjamin M.; Haworth, Steven T.; Clough, Anne V.

    2014-03-01

    Dual modality micro-CT and SPECT imaging can play an important role in preclinical studies designed to investigate mechanisms, progression, and therapies for acute lung injury in rats. SPECT imaging involves examining the uptake of radiopharmaceuticals within the lung, with the hypothesis that uptake is sensitive to the health or disease status of the lung tissue. Methods of quantifying lung uptake and comparison of right and left lung uptake generally begin with identifying and segmenting the lung region within the 3D reconstructed SPECT volume. However, identification of the lung boundaries and the fissure between the left and right lung is not always possible from the SPECT images directly since the radiopharmaceutical may be taken up by other surrounding tissues. Thus, our SPECT protocol begins with a fast CT scan, the lung boundaries are identified from the CT volume, and the CT region is coregistered with the SPECT volume to obtain the SPECT lung region. Segmenting rat lungs within the CT volume is particularly challenging due to the relatively low resolution of the images and the rat's unique anatomy. Thus, we have developed an automated segmentation algorithm for low resolution micro-CT scans that utilizes depth maps to detect fissures on the surface of the lung volume. The fissure's surface location is in turn used to interpolate the fissure throughout the lung volume. Results indicate that the segmentation method results in left and right lung regions consistent with rat lung anatomy.

  10. Visualisation of the Bonebridge by means of CT and CBCT

    PubMed Central

    2013-01-01

    Background With the Bonebridge, a new bone-anchored hearing aid has been available since March 2012. The objective of the study was to analyse the visualisation of the implant itself as well as its impact on the representation of the bony structures of the petrosal bone in CT, MRI and cone beam CT (CBCT). Methods The Bonebridge was implanted unilaterally in two completely prepared human heads. The radiological imaging by means of CBCT, 64-slice CT, 1.5-T and 3.0-T MRI was conducted both preoperatively and postoperatively. The images were subsequently evaluated from both the ENT medical and nd radiological perspectives. Results As anticipated, no visualisation of the implant or of the petrosal bones could be realised on MRI because of the interactive technology and the magnet artefact. In contrast, an excellent evaluability of the implant itself as well as of the surrounding neurovascular structures (sinus sigmoideus, skull base, middle ear, inner ear, inner auditory canal) was exhibited in both the CT and in the CBCT. Conclusion The Bonebridge can be excellently imaged with the radiological imaging technologies of CT and CBCT. In the process, CBCT shows discrete advantages in comparison with CT. No relevant restrictions in image quality in the evaluation of the bony structures of the petrosal bones could be seen. PMID:24004903

  11. Comparison of Intrahepatic and Pancreatic Perfusion on Fusion Images Using a Combined SPECT/CT System and Assessment of Efficacy of Combined Continuous Arterial Infusion and Systemic Chemotherapy in Advanced Pancreatic Carcinoma

    SciTech Connect

    Ikeda, Osama Tamura, Yoshitaka; Nakasone, Yutaka; Shiraishi, Shinya; Kawanaka, Kouichi; Tomiguchi, Seiji; Yamashita, Yasuyuki; Takamori, Hiroshi; Kanemitsu, Keiichiro; Baba, Hideo

    2007-09-15

    Purpose. The purpose of this study was to compare intrahepatic and pancreatic perfusion on fusion images using a combined single-photon emission computed tomography (SPECT)/CT system and to evaluate the efficacy of combined continuous transcatheter arterial infusion (CTAI) and systemic chemotherapy in the treatment of advanced pancreatic carcinoma. Materials and Methods. CTAI was performed in 33 patients (22 men, 11 women; age range, 35-77 years; mean age, 60 years) with stage IV pancreatic cancer with liver metastasis. The reservoir was transcutaneously implanted with the help of angiography. The systemic administration of gemcitabine was combined with the infusion of 5-fluorouracil via the reservoir. In all patients we obtained fusion images using a combined SPECT/CT system. Pancreatic perfusion on fusion images was classified as perfusion presence or as perfusion absent in the pancreatic cancer. Using WHO criteria we recorded the tumor response after 3 months on multislice helical CT scans. Treatment effects were evaluated based on the pancreatic cancer, liver metastasis, and factors such as intrahepatic and pancreatic perfusion on fusion images. For statistical analysis we used the chi-square test; survival was evaluated by the Kaplan Meier method (log-rank test). Results. On fusion images, pancreatic and intrahepatic perfusion was recorded as hot spot and as homogeneous distribution, respectively, in 18 patients (55%) and as cold spot and heterogeneous distribution, respectively, in 15 (45%). Patients with hot spot in the pancreatic tumor and homogeneous distribution in the liver manifested better treatment results (p < 0.05 and p < 0.01, respectively). Patients with hot spot both in the pancreatic cancer and in the liver survived longer than those with cold spot in the pancreatic cancer and heterogeneous distribution in the liver (median {+-} SD, 16.0 {+-} 3.7 vs. 8.0 {+-} 1.4 months; p < 0.05). Conclusions. We conclude that in patients with advanced

  12. Prospects for in vivo estimation of photon linear attenuation coefficients using postprocessing dual-energy CT imaging on a commercial scanner: Comparison of analytic and polyenergetic statistical reconstruction algorithms

    PubMed Central

    Evans, Joshua D.; Whiting, Bruce R.; O’Sullivan, Joseph A.; Politte, David G.; Klahr, Paul H.; Yu, Yaduo; Williamson, Jeffrey F.

    2013-01-01

    Purpose: Accurate patient-specific photon cross-section information is needed to support more accurate model-based dose calculation for low energy photon-emitting modalities in medicine such as brachytherapy and kilovoltage x-ray imaging procedures. A postprocessing dual-energy CT (pDECT) technique for noninvasive in vivo estimation of photon linear attenuation coefficients has been experimentally implemented on a commercial CT scanner and its accuracy assessed in idealized phantom geometries. Methods: Eight test materials of known composition and density were used to compare pDECT-estimated linear attenuation coefficients to NIST reference values over an energy range from 10 keV to 1 MeV. As statistical image reconstruction (SIR) has been shown to reconstruct images with less random and systematic error than conventional filtered backprojection (FBP), the pDECT technique was implemented with both an in-house polyenergetic SIR algorithm, alternating minimization (AM), as well as a conventional FBP reconstruction algorithm. Improvement from increased spectral separation was also investigated by filtering the high-energy beam with an additional 0.5 mm of tin. The law of propagated uncertainty was employed to assess the sensitivity of the pDECT process to errors in reconstructed images. Results: Mean pDECT-estimated linear attenuation coefficients for the eight test materials agreed within 1% of NIST reference values for energies from 1 MeV down to 30 keV, with mean errors rising to between 3% and 6% at 10 keV, indicating that the method is unbiased when measurement and calibration phantom geometries are matched. Reconstruction with FBP and AM algorithms conferred similar mean pDECT accuracy. However, single-voxel pDECT estimates reconstructed on a 1 × 1 × 3 mm3 grid are shown to be highly sensitive to reconstructed image uncertainty; in some cases pDECT attenuation coefficient estimates exhibited standard deviations on the order of 20% around the mean

  13. Thoracic textilomas: CT findings*

    PubMed Central

    Machado, Dianne Melo; Zanetti, Gláucia; Araujo, Cesar Augusto; Nobre, Luiz Felipe; Meirelles, Gustavo de Souza Portes; Pereira e Silva, Jorge Luiz; Guimarães, Marcos Duarte; Escuissato, Dante Luiz; Souza, Arthur Soares; Hochhegger, Bruno; Marchiori, Edson

    2014-01-01

    OBJECTIVE: The aim of this study was to analyze chest CT scans of patients with thoracic textiloma. METHODS: This was a retrospective study of 16 patients (11 men and 5 women) with surgically confirmed thoracic textiloma. The chest CT scans of those patients were evaluated by two independent observers, and discordant results were resolved by consensus. RESULTS: The majority (62.5%) of the textilomas were caused by previous heart surgery. The most common symptoms were chest pain (in 68.75%) and cough (in 56.25%). In all cases, the main tomographic finding was a mass with regular contours and borders that were well-defined or partially defined. Half of the textilomas occurred in the right hemithorax and half occurred in the left. The majority (56.25%) were located in the lower third of the lung. The diameter of the mass was ≤ 10 cm in 10 cases (62.5%) and > 10 cm in the remaining 6 cases (37.5%). Most (81.25%) of the textilomas were heterogeneous in density, with signs of calcification, gas, radiopaque marker, or sponge-like material. Peripheral expansion of the mass was observed in 12 (92.3%) of the 13 patients in whom a contrast agent was used. Intraoperatively, pleural involvement was observed in 14 cases (87.5%) and pericardial involvement was observed in 2 (12.5%). CONCLUSIONS: It is important to recognize the main tomographic aspects of thoracic textilomas in order to include this possibility in the differential diagnosis of chest pain and cough in patients with a history of heart or thoracic surgery, thus promoting the early identification and treatment of this postoperative complication. PMID:25410842

  14. Helical CT in emergency radiology.

    PubMed

    Novelline, R A; Rhea, J T; Rao, P M; Stuk, J L

    1999-11-01

    Today, a wide range of traumatic and nontraumatic emergency conditions are quickly and accurately diagnosed with helical computed tomography (CT). Many traditional emergency imaging procedures have been replaced with newer helical CT techniques that can be performed in less time and with greater accuracy, less patient discomfort, and decreased cost. The speed of helical technology permits CT examination of seriously ill patients in the emergency department, as well as patients who might not have been taken to CT previously because of the length of the examinations of the past. Also, helical technology permits multiple, sequential CT scans to be quickly obtained in the same patient, a great advance for the multiple-trauma patient. Higher quality CT examinations result from decreased respiratory misregistration, enhanced intravenous contrast material opacification of vascular structures and parenchymal organs, greater flexibility in image reconstruction, and improved multiplanar and three-dimensional reformations. This report summarizes the role and recommended protocols for the helical CT diagnosis of thoracic aortic trauma; aortic dissection; pulmonary embolism; acute conditions of the neck soft tissues; abdominal trauma; urinary tract stones; appendicitis; diverticulitis; abdominal aortic aneurysm; fractures of the face, spine, and extremities; and acute stroke.

  15. Comparison of the diagnostic accuracy of FBP, ASiR, and MBIR reconstruction during CT angiography in the evaluation of a vessel phantom with calcified stenosis in a distal superficial femoral artery in a cadaver extremity

    PubMed Central

    Tsukada, Jitsuro; Yamada, Minoru; Yamada, Yoshitake; Yamazaki, Shun; Imanishi, Nobuaki; Tamura, Kentaro; Hashimoto, Masahiro; Nakatsuka, Seishi; Jinzaki, Masahiro

    2016-01-01

    Abstract Purpose: To investigate whether adaptive statistical iterative reconstruction (ASiR) or model-based iterative reconstruction (MBIR) improves the diagnostic performance of computed tomography angiography (CTA) for small-vessel calcified lesions relative to filtered back projection (FBP) using cadaver extremities and a calcified stenosis phantom. Methods: A cadaver was used in accordance with our institutional regulations, and a calcified stenosis phantom simulating 4 grades of stenosis was prepared. The phantom was inserted within the distal superficial femoral artery of the cadaver leg. Ten CT images per reconstruction type and stenosis grade were acquired using a 64-slice multidetector-row CTA. As an objective measurement, the first and second derivatives of the CT value function profiles were calculated. As a subjective measurement, 2 blinded reviewers measured the stenosis ratio using a quantitative scale. The Wilcoxon rank-sum test was used to evaluate the data. Results: Objective measurements of both 25% and 50% stenosis differed significantly (P < 0.01) between MBIR (25/50%: 25.80/50.30 ± 3.88/3.86%) and FBP (25/50%: 35.60/83.80 ± 3.44/26.10%), whereas significant differences were not observed between ASiR and FBP. Reviewer 2's subjective measurements of 25% stenosis differed significantly (P < 0.01) between MBIR (35.13 ± 3.25%) and ASiR (40.89 ± 3.14%), and the measurements of 50% stenosis differed significantly (P < 0.01) between MBIR (reviewers 1/2, 62.36/54.78 ± 2.78/4.96%) and FBP (reviewers 1/2, 62.36/74.84 ± 2.78/18.10%). Significant differences in the subjective measurements were not observed between ASiR and FBP. Conclusion: MBIR improves the diagnostic performance of CTA for small-vessel calcified lesions relative to FBP. PMID:27399123

  16. Comparison on Response and Dissolution Rates Between Ursodeoxycholic Acid Alone or in Combination With Chenodeoxycholic Acid for Gallstone Dissolution According to Stone Density on CT Scan: Strobe Compliant Observation Study.

    PubMed

    Lee, Jae Min; Hyun, Jong Jin; Choi, In Young; Yeom, Suk Keu; Kim, Seung Young; Jung, Sung Woo; Jung, Young Kul; Koo, Ja Seol; Yim, Hyung Joon; Lee, Hong Sik; Lee, Sang Woo; Kim, Chang Duck

    2015-12-01

    Medical dissolution of gallstone is usually performed on radiolucent gallstones in a functioning gallbladder. However, absence of visible gallstone on plain abdominal x-ray does not always preclude calcification. This study aims to compare the response and dissolution rates between ursodeoxycholic acid (UDCA) alone or in combination with chenodeoxycholic acid (CDCA) according to stone density on computed tomography (CT) scan. A total of 126 patients underwent dissolution therapy with either UDCA alone or combination of CDCA and UDCA (CNU) from December 2010 to March 2014 at Korea University Ansan Hospital. In the end, 81 patients (CNU group = 44, UDCA group = 37) completed dissolution therapy for 6 months. Dissolution rate (percentage reduction in the gallstone volume) and response to therapy (complete dissolution or partial dissolution defined as reduction in stone volume of >50%) were compared between the 2 groups. Dissolution and response rates of sludge was also compared between the 2 groups. The overall response rate was 50.6% (CNU group 43.2% vs UDCA group 59.5%, P = 0.14), and the overall dissolution rate was 48.34% (CNU group 41.5% vs UDCA group 56.5%, P = 0.13). When analyzed according to stone density, response rate was 33.3%, 87.1%, 30.0%, and 6.2% for hypodense, isodense, hyperdense, and calcified stones, respectively. Response rate (85.7% vs 88.2%, P = 0.83) and dissolution rate (81.01% vs 85.38%, P = 0.17) of isodense stones were similar between CNU and UDCA group. When only sludge was considered, the overall response rate was 87.5% (CNU group 71.4% vs UDCA group 94.1%, P = 0.19), and the overall dissolution rate was 85.42% (CNU group 67.9% vs UDCA group 92.7%, P = 0.23). Patients with isodense gallstones and sludge showed much better response to dissolution therapy with CNU and UDCA showing comparable efficacy. Therefore, CT scan should be performed before medication therapy if stone dissolution is intended.

  17. MULTIMODALITY IMAGING: BEYOND PET/CT AND SPECT/CT

    PubMed Central

    Cherry, Simon R.

    2009-01-01

    Multimodality imaging with PET/CT and SPECT/CT has become commonplace in clinical practice and in preclinical and basic medical research. Do other combinations of imaging modalities have a similar potential to impact medical science and clinical medicine? The combination of PET or SPECT with MRI is an area of active research at the present time, while other, perhaps less obvious combinations, including CT/MR and PET/optical also are being studied. In addition to the integration of the instrumentation, there are parallel developments in synthesizing imaging agents that can be viewed by multiple imaging modalities. Is the fusion of PET and SPECT with CT the ultimate answer in multimodality imaging, or is it just the first example of a more general trend towards harnessing the complementary nature of the different modalities on integrated imaging platforms? PMID:19646559

  18. A comparison of directed search target detection versus in-scene target detection in Worldview-2 datasets

    NASA Astrophysics Data System (ADS)

    Grossman, S.

    2015-05-01

    Since the events of September 11, 2001, the intelligence focus has moved from large order-of-battle targets to small targets of opportunity. Additionally, the business community has discovered the use of remotely sensed data to anticipate demand and derive data on their competition. This requires the finer spectral and spatial fidelity now available to recognize those targets. This work hypothesizes that directed searches using calibrated data perform at least as well as inscene manually intensive target detection searches. It uses calibrated Worldview-2 multispectral images with NEF generated signatures and standard detection algorithms to compare bespoke directed search capabilities against ENVI™ in-scene search capabilities. Multiple execution runs are performed at increasing thresholds to generate detection rates. These rates are plotted and statistically analyzed. While individual head-to-head comparison results vary, 88% of the directed searches performed at least as well as in-scene searches with 50% clearly outperforming in-scene methods. The results strongly support the premise that directed searches perform at least as well as comparable in-scene searches.

  19. Comparison of Endoscopic Vacuum Therapy and Endoscopic Stent Implantation With Self-Expandable Metal Stent in Treating Postsurgical Gastroesophageal Leakage

    PubMed Central

    Hwang, Jae J.; Jeong, Yeon S.; Park, Young S.; Yoon, Hyuk; Shin, Cheol M.; Kim, Nayoung; Lee, Dong H.

    2016-01-01

    Abstract The aim of the present study was to evaluate the more effective therapy for the postsurgical gastroesophageal leakage by a head-to-head comparison of endoscopic vacuum therapy (EVT) and endoscopic stent implantation with self-expandable metal stent (E-SEMS). In this hospital-based, retrospective, observative study, the patients were classified into 2 groups. Those treated with EVT were assigned to the EVT group (n = 7), and those treated with E-SMS were assigned to the E-SEMS group (n = 11). We evaluated the clinical characteristics and treatment outcomes between the 2 groups. All 7 patients (100%) were treated with EVT, but only 7 of 11 patients (63.6%) in the stenting group were treated successfully. The median time to clinical success was 19.5 (5–21) days in the EVT group and 27.0 (3–84) days in the E-SEMS group. The median hospital stay was 37.1 (13–128) days in the EVT group and 87.3 (17–366) days in the E-SEMS group. The complicaion rate was lower in the EVT group (0/7, 0.0%) than that in the E-SEMS group (6/11, 54.5%) with statistically significant difference (P = 0.042). EVT is more effective and has fewer adverse effects than E-SMS therapy as a treatment for postsurgical gastroesophageal leakage. PMID:27100431

  20. Comparison of Endoscopic Vacuum Therapy and Endoscopic Stent Implantation With Self-Expandable Metal Stent in Treating Postsurgical Gastroesophageal Leakage.

    PubMed

    Hwang, Jae J; Jeong, Yeon S; Park, Young S; Yoon, Hyuk; Shin, Cheol M; Kim, Nayoung; Lee, Dong H

    2016-04-01

    The aim of the present study was to evaluate the more effective therapy for the postsurgical gastroesophageal leakage by a head-to-head comparison of endoscopic vacuum therapy (EVT) and endoscopic stent implantation with self-expandable metal stent (E-SEMS). In this hospital-based, retrospective, observative study, the patients were classified into 2 groups. Those treated with EVT were assigned to the EVT group (n = 7), and those treated with E-SMS were assigned to the E-SEMS group (n = 11). We evaluated the clinical characteristics and treatment outcomes between the 2 groups. All 7 patients (100%) were treated with EVT, but only 7 of 11 patients (63.6%) in the stenting group were treated successfully. The median time to clinical success was 19.5 (5-21) days in the EVT group and 27.0 (3-84) days in the E-SEMS group. The median hospital stay was 37.1 (13-128) days in the EVT group and 87.3 (17-366) days in the E-SEMS group. The complicaion rate was lower in the EVT group (0/7, 0.0%) than that in the E-SEMS group (6/11, 54.5%) with statistically significant difference (P = 0.042). EVT is more effective and has fewer adverse effects than E-SMS therapy as a treatment for postsurgical gastroesophageal leakage.

  1. Errors in CT colonography.

    PubMed

    Trilisky, Igor; Ward, Emily; Dachman, Abraham H

    2015-10-01

    CT colonography (CTC) is a colorectal cancer screening modality which is becoming more widely implemented and has shown polyp detection rates comparable to those of optical colonoscopy. CTC has the potential to improve population screening rates due to its minimal invasiveness, no sedation requirement, potential for reduced cathartic examination, faster patient throughput, and cost-effectiveness. Proper implementation of a CTC screening program requires careful attention to numerous factors, including patient preparation prior to the examination, the technical aspects of image acquisition, and post-processing of the acquired data. A CTC workstation with dedicated software is required with integrated CTC-specific display features. Many workstations include computer-aided detection software which is designed to decrease errors of detection by detecting and displaying polyp-candidates to the reader for evaluation. There are several pitfalls which may result in false-negative and false-positive reader interpretation. We present an overview of the potential errors in CTC and a systematic approach to avoid them.

  2. A mixed treatment comparison to compare the efficacy and safety of botulinum toxin treatments for cervical dystonia.

    PubMed

    Han, Yi; Stevens, Andrea L; Dashtipour, Khashayar; Hauser, Robert A; Mari, Zoltan

    2016-04-01

    A systematic pair-wise comparison of all available botulinum toxin serotype A and B treatments for cervical dystonia (CD) was conducted, as direct head-to-head clinical trial comparisons are lacking. Five botulinum toxin products: Dysport(®) (abobotulinumtoxinA), Botox(®) (onabotulinumtoxinA), Xeomin(®) (incobotulinumtoxinA), Prosigne(®) (Chinese botulinum toxin serotype A) and Myobloc(®) (rimabotulinumtoxinB) have demonstrated efficacy for managing CD. A pair-wise efficacy and safety comparison was performed for all toxins based on literature-reported clinical outcomes. Multi-armed randomized controlled trials (RCTs) were identified for inclusion using a systematic literature review, and assessed for comparability based on patient population and efficacy outcome measures. The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) was selected as the efficacy outcome measurement for assessment. A mixed treatment comparison (MTC) was conducted using a Bayesian hierarchical model allowing indirect comparison of the interventions. Due to the limitation of available clinical data, this study only investigated the main effect of toxin treatments without explicitly considering potential confounding factors such as gender and formulation differences. There was reasonable agreement between the number of unconstrained data points, residual deviance and pair-wise results. This research suggests that all botulinum toxin serotype A and serotype B treatments were effective compared to placebo in treating CD, with the exception of Prosigne. Based on this MTC analysis, there is no significant efficacy difference between Dysport, Botox, Xeomin and Myobloc at week four post injection. Of the adverse events measured, neither dysphagia nor injection site pain was significantly greater in the treatment or placebo groups.

  3. Greening America's Capitals - Hartford, CT

    EPA Pesticide Factsheets

    This Greening America's Capitals report gives Hartford, CT, a new vision for Capitol Avenue that highlights existing assets and fills in gaps along the mile-long area of focus and into the surrounding neighborhoods.

  4. Multiplanar CT of the spine

    SciTech Connect

    Rothman, S.L.G.; Glenn, W.V. Jr.

    1986-01-01

    This is an illustrated text on computed tomography (CT) of the lumbar spine with an emphasis on the role and value of multiplanar imaging for helping determine diagnoses. The book has adequate discussion of scanning techniques for the different regions, interpretations of various abnormalities, degenerative disk disease, and different diagnoses. There is a 50-page chapter on detailed sectional anatomy of the spine and useful chapters on the postoperative spine and the planning and performing of spinal surgery with CT multiplanar reconstruction. There are comprehensive chapters on spinal tumors and trauma. The final two chapters of the book are devoted to CT image processing using digital networks and CT applications of medical computer graphics.

  5. CT Perfusion of the Head

    MedlinePlus

    ... ray beam follows a spiral path. A special computer program processes this large volume of data to create ... process. Nearly all CT scanners now have special computer programs that help to increase image quality at lower ...

  6. CT Demonstration of Caput Medusae

    ERIC Educational Resources Information Center

    Weber, Edward C.; Vilensky, Joel A.

    2009-01-01

    Maximum intensity and volume rendered CT displays of caput medusae are provided to demonstrate both the anatomy and physiology of this portosystemic shunt associated with portal hypertension. (Contains 2 figures.)

  7. Adrenal cortex dysfunction: CT findings

    SciTech Connect

    Huebener, K.H.; Treugut, H.

    1984-01-01

    The computed tomographic appearance of the adrenal gland was studied in 302 patients with possible endocrinologic disease and 107 patients undergoing CT for nonendocrinologic reasons. Measurements of adrenal size were also made in 100 adults with no known adrenal pathology. CT proved to be a sensitive diagnostic tool in combination with clinical studies. When blood hormone levels are increased, CT can differentiate among homogeneous organic hyperplasia, nodular hyperplasia, benign adenoma, and malignant cortical adenoma. When blood hormone levels are decreased, CT can demonstrate hypoplasia or metastatic tumorous destruction. Calcifications can be demonstrated earlier than on plain radiographs. When hormone elimination is increased, the morphologic substrate can be identified; tumorous changes can be localized and infiltration of surrounding organs recognized.

  8. Children's (Pediatric) CT (Computed Tomography)

    MedlinePlus Videos and Cool Tools

    ... What are the limitations of Children's CT? A person who is very large may not fit into ... facility staff and/or your insurance provider to get a better understanding of the possible charges you ...

  9. CT angiography - head and neck

    MedlinePlus

    ... medlineplus.gov/ency/article/007677.htm CT angiography - head and neck To use the sharing features on this page, ... create pictures of the blood vessels in the head and neck. How the Test is Performed You will be ...

  10. Multiplanar CT of the spine

    SciTech Connect

    Rothman, S.L.G.; Glenn, W.V.

    1985-01-01

    This book contains 16 chapters. Some of the topics are: CT of the Sacrum, The Postoperative Spine, Film Organizations and Case Reporting, Degeneration and Disc Disease of the Intervertebral Joint, Lumbar Spinal Stenosis, and Cervical and Thoracic Spine.

  11. A tonsillolith seen on CT.

    PubMed

    Espe, B J; Newmark, H

    1992-01-01

    A case of a large tonsillolith visualized by computerized tomography is presented. Although otolaryngologists are well aware of this entity, few radiologists are. The importance of distinguishing tonsilloliths from other structures by CT scan is discussed.

  12. Liver echinococcus - CT scan (image)

    MedlinePlus

    This upper abdominal CT scan shows multiple cysts in the liver, caused by dog tapeworm (echinococcus). Note the large circular cyst (seen on the left side of the screen) and multiple smaller cysts throughout ...

  13. Patient radiation doses for electron beam CT

    SciTech Connect

    Castellano, Isabel A.; Dance, David R.; Skinner, Claire L.; Evans, Phil M.

    2005-08-15

    A Monte Carlo based computer model has been developed for electron beam computed tomography (EBCT) to calculate organ and effective doses in a humanoid hermaphrodite phantom. The program has been validated by comparison with experimental measurements of the CT dose index in standard head and body CT dose phantoms; agreement to better than 8% has been found. The robustness of the model has been established by varying the input parameters. The amount of energy deposited at the 12:00 position of the standard body CT dose phantom is most susceptible to rotation angle, whereas that in the central region is strongly influenced by the beam quality. The program has been used to investigate the changes in organ absorbed doses arising from partial and full rotation about supine and prone subjects. Superficial organs experience the largest changes in absorbed dose with a change in subject orientation and for partial rotation. Effective doses for typical clinical scan protocols have been calculated and compared with values obtained using existing dosimetry techniques based on full rotation. Calculations which make use of Monte Carlo conversion factors for the scanner that best matches the EBCT dosimetric characteristics consistently overestimate the effective dose in supine subjects by typically 20%, and underestimate the effective dose in prone subjects by typically 13%. These factors can therefore be used to correct values obtained in this way. Empirical dosimetric techniques based on the dose-length product yield errors as great as 77%. This is due to the sensitivity of the dose length product to individual scan lengths. The magnitude of these errors is reduced if empirical dosimetric techniques based on the average absorbed dose in the irradiated volume (CTDI{sub vol}) are used. Therefore conversion factors specific to EBCT have been calculated to convert the CTDI{sub vol} to an effective dose.

  14. Primary lower extremity lymphedema: CT diagnosis

    SciTech Connect

    Gamba, J.L.; Silverman, P.M.; Ling, D.; Dunnick, N.R.; Korobkin, M.

    1983-10-01

    The CT findings of two cases of primary lymphedema of the lower extremities are presented. CT showed a coarse, nonenhancing, reticular pattern in an enlarged subcutaneous compartment. CT excluded the diagnosis of secondary lymphedema from an obstructing mass by demonstrating a normal retroperitoneum and pelvis. The CT findings are correlated with pedal lymphangiograms.

  15. Primary epiploic appendagitis: CT diagnosis.

    PubMed

    Sandrasegaran, Kumaresan; Maglinte, Dean D; Rajesh, Arumugam; Akisik, Fatih M

    2004-08-01

    The purpose of this study was to analyze the CT signs of primary epiploic appendagitis. A retrospective search of the CT database over 12 months for this diagnosis revealed 11 cases. The clinical findings were recorded. Softcopy CT images were reviewed by two experienced abdominal radiologists (KS, DM) for location of lesion, size, shape, presence of central hyperdense focus, degree of bowel wall thickening, mass effect, and ancillary signs. Abdominal pain was the primary symptom in all patients. Preliminary diagnoses were appendicitis (n=2), diverticulitis (n=5), pancreatitis (n=1), ovarian lesion (n=1), or unknown (n=2). Abdominal examination and white blood cell count were uninformative. CT examination revealed a solitary (n=11), ovoid (n=9) fatty lesion with some soft tissue stranding adjacent to the left colon (n=6), transverse colon (n=3), or right colon (n=2). Central hyperdensity (n=5), mild bowel wall thickening (n=2), and parietal peritoneal thickening (n=4) were also seen. In 4 patients the lesions were not visible on follow-up CT examination performed 23-184 days later. Primary epiploic appendagitis can clinically mimic other, more serious inflammatory conditions. Knowledge of its findings on CT would help the radiologist make the diagnosis and allow a more conservative approach to patient care.

  16. Physical and clinical performance of the mCT time-of-flight PET/CT scanner

    NASA Astrophysics Data System (ADS)

    Jakoby, B. W.; Bercier, Y.; Conti, M.; Casey, M. E.; Bendriem, B.; Townsend, D. W.

    2011-04-01

    Time-of-flight (TOF) measurement capability promises to improve PET image quality. We characterized the physical and clinical PET performance of the first Biograph mCT TOF PET/CT scanner (Siemens Medical Solutions USA, Inc.) in comparison with its predecessor, the Biograph TruePoint TrueV. In particular, we defined the improvements with TOF. The physical performance was evaluated according to the National Electrical Manufacturers Association (NEMA) NU 2-2007 standard with additional measurements to specifically address the TOF capability. Patient data were analyzed to obtain the clinical performance of the scanner. As expected for the same size crystal detectors, a similar spatial resolution was measured on the mCT as on the TruePoint TrueV. The mCT demonstrated modestly higher sensitivity (increase by 19.7 ± 2.8%) and peak noise equivalent count rate (NECR) (increase by 15.5 ± 5.7%) with similar scatter fractions. The energy, time and spatial resolutions for a varying single count rate of up to 55 Mcps resulted in 11.5 ± 0.2% (FWHM), 527.5 ± 4.9 ps (FWHM) and 4.1 ± 0.0 mm (FWHM), respectively. With the addition of TOF, the mCT also produced substantially higher image contrast recovery and signal-to-noise ratios in a clinically-relevant phantom geometry. The benefits of TOF were clearly demonstrated in representative patient images.

  17. Cardiac cone-beam CT

    SciTech Connect

    Manzke, Robert . E-mail: robert.manzke@philips.com

    2005-10-15

    This doctoral thesis addresses imaging of the heart with retrospectively gated helical cone-beam computed tomography (CT). A thorough review of the CT reconstruction literature is presented in combination with a historic overview of cardiac CT imaging and a brief introduction to other cardiac imaging modalities. The thesis includes a comprehensive chapter about the theory of CT reconstruction, familiarizing the reader with the problem of cone-beam reconstruction. The anatomic and dynamic properties of the heart are outlined and techniques to derive the gating information are reviewed. With the extended cardiac reconstruction (ECR) framework, a new approach is presented for the heart-rate-adaptive gated helical cardiac cone-beam CT reconstruction. Reconstruction assessment criteria such as the temporal resolution, the homogeneity in terms of the cardiac phase, and the smoothness at cycle-to-cycle transitions are developed. Several reconstruction optimization approaches are described: An approach for the heart-rate-adaptive optimization of the temporal resolution is presented. Streak artifacts at cycle-to-cycle transitions can be minimized by using an improved cardiac weighting scheme. The optimal quiescent cardiac phase for the reconstruction can be determined automatically with the motion map technique. Results for all optimization procedures applied to ECR are presented and discussed based on patient and phantom data. The ECR algorithm is analyzed for larger detector arrays of future cone-beam systems throughout an extensive simulation study based on a four-dimensional cardiac CT phantom. The results of the scientific work are summarized and an outlook proposing future directions is given. The presented thesis is available for public download at www.cardiac-ct.net.

  18. Assessment of bilateral filter on 1/2-dose chest-pelvis CT views.

    PubMed

    Al-Hinnawi, Abdel Razzak; Daear, Mohammed; Huwaijah, Said

    2013-07-01

    A bilateral filter (BF) is a non-linear filter that has been proved to de-noise images without overrunning edges. Multi-slice computerized tomography (CT) may employ a BF to participate in dose reduction. This paper quantifies the role of the BF in achieving this objective on 1/2-dose CT. Two sets of CT images are acquired for the chest-pelvis at two different radiation doses. The BF was applied on the 1/2-dose CT images by use of various window sizes. Each time, a set of values of the BF range was fixed while the BF domain was modified. The goal was to observe the behavior of the BF on 1/2-dose CT images in comparison with full-dose CT images. The comparison was carried out by use of four co-occurrence matrix descriptors. Additionally, the peak signal-to-noise ratio (PSNR) and the mean square error (MSE) were reported. The study was applied to the sagittal, coronal, and axial CT views. The results showed that the impact of applying a BF varies among different CT views. The BF can retrieve only part of the signal being lost due to reduction of the radiation dose by one half. Yet, the BF improves the appearance of the 1/2-dose chest-pelvis CT examination. Thus, the BF can contribute to a 50% dose reduction. A procedure for employing the BF on CT machines is proposed. The results also showed that texture descriptors are similar to the PSNR and MSE in providing quantities for assessing medical image quality.

  19. TU-G-201-01: What Therapy Physicists Need to Know About CT and PET/CT: Terminology and Latest Developments

    SciTech Connect

    Hua, C.

    2015-06-15

    , and PET/CT Understand the process of budget request, equipment justification, comparisons of technical specifications, site visits, vendor selection, and contract development.

  20. Augmenting CT cardiac roadmaps with segmented streaming ultrasound

    NASA Astrophysics Data System (ADS)

    Duan, Qi; Shechter, Guy; Gutiérrez, Luis F.; Stanton, Douglas; Zagorchev, Lyubomir; Laine, Andrew F.; Elgort, Daniel R.

    2007-03-01

    Static X-ray computed tomography (CT) volumes are often used as anatomic roadmaps during catheter-based cardiac interventions performed under X-ray fluoroscopy guidance. These CT volumes provide a high-resolution depiction of soft-tissue structures, but at only a single point within the cardiac and respiratory cycles. Augmenting these static CT roadmaps with segmented myocardial borders extracted from live ultrasound (US) provides intra-operative access to real-time dynamic information about the cardiac anatomy. In this work, using a customized segmentation method based on a 3D active mesh, endocardial borders of the left ventricle were extracted from US image streams (4D data sets) at a frame rate of approximately 5 frames per second. The coordinate systems for CT and US modalities were registered using rigid body registration based on manually selected landmarks, and the segmented endocardial surfaces were overlaid onto the CT volume. The root-mean squared fiducial registration error was 3.80 mm. The accuracy of the segmentation was quantitatively evaluated in phantom and human volunteer studies via comparison with manual tracings on 9 randomly selected frames using a finite-element model (the US image resolutions of the phantom and volunteer data were 1.3 x 1.1 x 1.3 mm and 0.70 x 0.82 x 0.77 mm, respectively). This comparison yielded 3.70+/-2.5 mm (approximately 3 pixels) root-mean squared error (RMSE) in a phantom study and 2.58+/-1.58 mm (approximately 3 pixels) RMSE in a clinical study. The combination of static anatomical roadmap volumes and dynamic intra-operative anatomic information will enable better guidance and feedback for image-guided minimally invasive cardiac interventions.

  1. GMctdospp: Description and validation of a CT dose calculation system

    SciTech Connect

    Schmidt, Ralph Wulff, Jörg; Zink, Klemens

    2015-07-15

    Purpose: To develop a Monte Carlo (MC)-based computed tomography (CT) dose estimation method with a graphical user interface with options to define almost arbitrary simulation scenarios, to make calculations sufficiently fast for comfortable handling, and to make the software free of charge for general availability to the scientific community. Methods: A framework called GMctdospp was developed to calculate phantom and patient doses with the MC method based on the EGSnrc system. A CT scanner was modeled for testing and was adapted to half-value layer, beam-shaping filter, z-profile, and tube-current modulation (TCM). To validate the implemented variance reduction techniques, depth-dose and cross-profile calculations of a static beam were compared against DOSXYZnrc/EGSnrc. Measurements for beam energies of 80 and 120 kVp at several positions of a CT dose-index (CTDI) standard phantom were compared against calculations of the created CT model. Finally, the efficiency of the adapted code was benchmarked against EGSnrc defaults. Results: The CT scanner could be modeled accurately. The developed TCM scheme was confirmed by the dose measurement. A comparison of calculations to DOSXYZnrc showed no systematic differences. Measurements in a CTDI phantom could be reproduced within 2% average, with a maximal difference of about 6%. Efficiency improvements of about six orders of magnitude were observed for larger organ structures of a chest-examination protocol in a voxelized phantom. In these cases, simulations took 25 s to achieve a statistical uncertainty of ∼0.5%. Conclusions: A fast dose-calculation system for phantoms and patients in a CT examination was developed, successfully validated, and benchmarked. Influences of scan protocols, protection method, and other issues can be easily examined with the developed framework.

  2. Malignant external otitis: CT evaluation

    SciTech Connect

    Curtin, H.D.; Wolfe, P.; May, M.

    1982-11-01

    Malignant external otitis is an aggressive infection caused by Pseudomonas aeruginosa that most often occurs in elderly diabetics. Malignant external otitis often spreads inferiorly from the external canal to involve the subtemporal area and progresses medially towards the petrous apex leading to multiple cranial nerve palsies. The computed tomographic (CT) findings in malignant external otitis include obliteration of the normal fat planes in the subtemporal area as well as patchy destruction of the bony cortex of the mastoid. The point of exit of the various cranial nerves can be identified on CT scans, and the extent of the inflammatory mass correlates well with the clinical findings. Four cases of malignant external otitis are presented. In each case CT provided a good demonstration of involvement of the soft tissues at the base of the skull.

  3. Generation of synthetic CT data using patient specific daily MR image data and image registration

    NASA Astrophysics Data System (ADS)

    Melanie Kraus, Kim; Jäkel, Oliver; Niebuhr, Nina I.; Pfaffenberger, Asja

    2017-02-01

    To fully exploit the advantages of magnetic resonance imaging (MRI) for radiotherapy (RT) treatment planning, a method is required to overcome the problem of lacking electron density information. We aim to establish and evaluate a new method for computed tomography (CT) data generation based on MRI and image registration. The thereby generated CT data is used for dose accumulation. We developed a process flow based on an initial pair of rigidly co-registered CT and T2-weighted MR image representing the same anatomical situation. Deformable image registration using anatomical landmarks is performed between the initial MRI data and daily MR images. The resulting transformation is applied to the initial CT, thus fractional CT data is generated. Furthermore, the dose for a photon intensity modulated RT (IMRT) or intensity modulated proton therapy (IMPT) plan is calculated on the generated fractional CT and accumulated on the initial CT via inverse transformation. The method is evaluated by the use of phantom CT and MRI data. Quantitative validation is performed by evaluation of the mean absolute error (MAE) between the measured and the generated CT. The effect on dose accumulation is examined by means of dose-volume parameters. One patient case is presented to demonstrate the applicability of the method introduced here. Overall, CT data derivation lead to MAEs with a median of 37.0 HU ranging from 29.9 to 66.6 HU for all investigated tissues. The accuracy of image registration showed to be limited in the case of unexpected air cavities and at tissue boundaries. The comparisons of dose distributions based on measured and generated CT data agree well with the published literature. Differences in dose volume parameters kept within 1.6% and 3.2% for photon and proton RT, respectively. The method presented here is particularly suited for application in adaptive RT in current clinical routine, since only minor additional technical equipment is required.

  4. Autoantibody Levels and Clinical Disease Severity in Patients with Pemphigus: Comparison of Aggregated Anti-desmoglein ELISA Values and Indirect Immunofluorescence Titres.

    PubMed

    Weiss, Doris; Ristl, Robin; Griss, Johannes; Bangert, Christine; Foedinger, Dagmar; Stingl, Georg; Brunner, Patrick M

    2015-05-01

    Detecting serum-autoantibodies by anti-Desmoglein-1 (anti-Dsg1) and anti-Dsg3 ELISAs as well as indirect immunofluorescence (IIF) are established complementary methods to diagnose pemphigus. Whether autoantibody levels also reflect clinical disease activity is still a matter of debate, as head-to-head comparisons of ELISA values and IIF titres with clinical activity over a longer treatment period are scarce. In our retrospective study, we compared aggregated repetitive intra-patient ELISA values and IIF titres with grades of clinical disease (1 = remission, 2 = moderate activity, 3 = exacerbation) in 47 patients suffering from pemphigus vulgaris (PV, n = 36) and pemphigus foliaceus (PF, n=11). We found that anti-Dsg1 ELISA values in PF and mucocutaneous PV as well as anti-Dsg3 ELISA values in PV best reflect disease activity. IIF titres, by contrast, did not show a significant association with disease severity. From these data we conclude that ELISA index values can be a valuable tool to monitor disease in patients with pemphigus, whereas IIF titres reflect clinical activity only insufficiently.

  5. Performance Comparison of Wireless Sensor Network Standard Protocols in an Aerospace Environment: ISA100.11a and ZigBee Pro

    NASA Technical Reports Server (NTRS)

    Wagner, Raymond S.; Barton, Richard J.

    2011-01-01

    Standards-based wireless sensor network (WSN) protocols are promising candidates for spacecraft avionics systems, offering unprecedented instrumentation flexibility and expandability. Ensuring reliable data transport is key, however, when migrating from wired to wireless data gathering systems. In this paper, we conduct a rigorous laboratory analysis of the relative performances of the ZigBee Pro and ISA100.11a protocols in a representative crewed aerospace environment. Since both operate in the 2.4 GHz radio frequency (RF) band shared by systems such as Wi-Fi, they are subject at times to potentially debilitating RF interference. We compare goodput (application-level throughput) achievable by both under varying levels of 802.11g Wi-Fi traffic. We conclude that while the simpler, more inexpensive ZigBee Pro protocol performs well under moderate levels of interference, the more complex and costly ISA100.11a protocol is needed to ensure reliable data delivery under heavier interference. This paper represents the first published, rigorous analysis of WSN protocols in an aerospace environment that we are aware of and the first published head-to-head comparison of ZigBee Pro and ISA100.11a.

  6. [Gallstone ileus. Abdominal CT usefulness].

    PubMed

    Sukkarieh, F; Brasseur, P; Bissen, L

    2004-06-01

    The authors report the case of a 93-year old woman referred to the emergency department and presenting with an intestinal obstruction. Abdominal CT reveals a biliary ileus caused by the migration and the impaction of a 3 cm gallstone in the small bowel. Surgical treatment by enterolithotomy was successful. In over 90% of cases, gallstone ileus is a complication of cholelithiasis and accounts for 25% of intestinal obstruction in patients over 65 years. To reduce morbidity and mortality, early diagnosis and prompt treatment are essential. Abdominal CT-scan is the gold standard technique.

  7. Granulocytic sarcoma (chloroma): CT manifestations

    SciTech Connect

    Pomeranz, S.J.; Hawkins, H.H.; Towbin, R.; Lisberg, W.N.; Clark, R.A.

    1985-04-01

    Nests of granulocytic tumor cells in patients who have myelogeneous leukemia are termed chloromas. Eight cases of chloroma seen on CT were reviewed. Lymph nodes, subcutaneous tissues, peritoneum, pleural space, pelvis, and portal hepatis were involved. The extracranial appearance of chloroma on CT is that of small, nonenhancing, nodular densities that resemble lymphoma. Cranial involvement is characteristically in the orbit. The central nervous system appearance is variable, however, and high attenuation masses may occur that mimic lymphoma, hematoma, and metastatic neuroblastoma. The recognition of these lesions is important, since radiation, not chemotherapy, is often the preferred treatment for localized chloroma.

  8. Ontological analysis of SNOMED CT

    PubMed Central

    Héja, Gergely; Surján, György; Varga, Péter

    2008-01-01

    Background SNOMED CT is the most comprehensive medical terminology. However, its use for intelligent services based on formal reasoning is questionable. Methods The analysis of the structure of SNOMED CT is based on the formal top-level ontology DOLCE. Results The analysis revealed several ontological and knowledge-engineering errors, the most important are errors in the hierarchy (mostly from an ontological point of view, but also regarding medical aspects) and the mixing of subsumption relations with other types (mostly 'part of'). Conclusion The found errors impede formal reasoning. The paper presents a possible way to correct these problems. PMID:19007445

  9. Method comparison of automated matching software-assisted cone-beam CT and stereoscopic kilovoltage x-ray positional verification image-guided radiation therapy for head and neck cancer: a prospective analysis

    PubMed Central

    Fuller, Clifton D; Scarbrough, Todd J; Sonke, Jan-Jakob; Rasch, Coen R N; Choi, Mehee; Ting, Joe Y; Wang, Samuel J; Papanikolaou, Niko; Rosenthal, David I

    2017-01-01

    We sought to characterize interchangeability and agreement between cone-beam computed tomography (CBCT) and digital stereoscopic kV x-ray (KVX) acquisition, two methods of isocenter positional verification currently used for IGRT of head and neck cancers (HNC). A cohort of 33 patients were near-simultaneously imaged by in-room KVX and CBCT. KVX and CBCT shifts were suggested using manufacturer software for the lateral (X), vertical (Y) and longitudinal (Z) dimensions. Intra-method repeatability, systematic and random error components were calculated for each imaging modality, as were recipe-based PTV expansion margins. Inter-method agreement in each axis was compared using limits of agreement (LOA) methodology, concordance analysis and orthogonal regression. 100 daily positional assessments were performed before daily therapy in 33 patients with head and neck cancer. Systematic error was greater for CBCT in all axes, with larger random error components in the Y- and Z-axis. Repeatability ranged from 9 to 14 mm for all axes, with CBCT showing greater repeatability in 2/3 axes. LOA showed paired shifts to agree 95% of the time within ±11.3 mm in the X-axis, ±9.4 mm in the Y-axis and ±5.5 mm in the Z-axis. Concordance ranged from ‘mediocre’ to ‘satisfactory’. Proportional bias was noted between paired X- and Z-axis measures, with a constant bias component in the Z-axis. Our data suggest non-negligible differences in software-derived CBCT and KVX image-guided directional shifts using formal method comparison statistics. PMID:19934488

  10. Method comparison of automated matching software-assisted cone-beam CT and stereoscopic kilovoltage x-ray positional verification image-guided radiation therapy for head and neck cancer: a prospective analysis

    NASA Astrophysics Data System (ADS)

    Fuller, Clifton D.; Scarbrough, Todd J.; Sonke, Jan-Jakob; Rasch, Coen R. N.; Choi, Mehee; Ting, Joe Y.; Wang, Samuel J.; Papanikolaou, Niko; Rosenthal, David I.

    2009-12-01

    We sought to characterize interchangeability and agreement between cone-beam computed tomography (CBCT) and digital stereoscopic kV x-ray (KVX) acquisition, two methods of isocenter positional verification currently used for IGRT of head and neck cancers (HNC). A cohort of 33 patients were near-simultaneously imaged by in-room KVX and CBCT. KVX and CBCT shifts were suggested using manufacturer software for the lateral (X), vertical (Y) and longitudinal (Z) dimensions. Intra-method repeatability, systematic and random error components were calculated for each imaging modality, as were recipe-based PTV expansion margins. Inter-method agreement in each axis was compared using limits of agreement (LOA) methodology, concordance analysis and orthogonal regression. 100 daily positional assessments were performed before daily therapy in 33 patients with head and neck cancer. Systematic error was greater for CBCT in all axes, with larger random error components in the Y- and Z-axis. Repeatability ranged from 9 to 14 mm for all axes, with CBCT showing greater repeatability in 2/3 axes. LOA showed paired shifts to agree 95% of the time within ±11.3 mm in the X-axis, ±9.4 mm in the Y-axis and ±5.5 mm in the Z-axis. Concordance ranged from 'mediocre' to 'satisfactory'. Proportional bias was noted between paired X- and Z-axis measures, with a constant bias component in the Z-axis. Our data suggest non-negligible differences in software-derived CBCT and KVX image-guided directional shifts using formal method comparison statistics. A correction was made to the first line of page 7404 of this article on 26 November 2009. The corrected electronic version is identical to the print version.

  11. PET/CT in radiation oncology

    SciTech Connect

    Pan, Tinsu; Mawlawi, Osama

    2008-11-15

    PET/CT is an effective tool for the diagnosis, staging and restaging of cancer patients. It combines the complementary information of functional PET images and anatomical CT images in one imaging session. Conventional stand-alone PET has been replaced by PET/CT for improved patient comfort, patient throughput, and most importantly the proven clinical outcome of PET/CT over that of PET and that of separate PET and CT. There are over two thousand PET/CT scanners installed worldwide since 2001. Oncology is the main application for PET/CT. Fluorine-18 deoxyglucose is the choice of radiopharmaceutical in PET for imaging the glucose uptake in tissues, correlated with an increased rate of glycolysis in many tumor cells. New molecular targeted agents are being developed to improve the accuracy of targeting different disease states and assessing therapeutic response. Over 50% of cancer patients receive radiation therapy (RT) in the course of their disease treatment. Clinical data have demonstrated that the information provided by PET/CT often changes patient management of the patient and/or modifies the RT plan from conventional CT simulation. The application of PET/CT in RT is growing and will become increasingly important. Continuing improvement of PET/CT instrumentation will also make it easier for radiation oncologists to integrate PET/CT in RT. The purpose of this article is to provide a review of the current PET/CT technology, to project the future development of PET and CT for PET/CT, and to discuss some issues in adopting PET/CT in RT and potential improvements in PET/CT simulation of the thorax in radiation therapy.

  12. "High-precision, reconstructed 3D model" of skull scanned by conebeam CT: Reproducibility verified using CAD/CAM data.

    PubMed

    Katsumura, Seiko; Sato, Keita; Ikawa, Tomoko; Yamamura, Keiko; Ando, Eriko; Shigeta, Yuko; Ogawa, Takumi

    2016-01-01

    Computed tomography (CT) scanning has recently been introduced into forensic medicine and dentistry. However, the presence of metal restorations in the dentition can adversely affect the quality of three-dimensional reconstruction from CT scans. In this study, we aimed to evaluate the reproducibility of a "high-precision, reconstructed 3D model" obtained from a conebeam CT scan of dentition, a method that might be particularly helpful in forensic medicine. We took conebeam CT and helical CT images of three dry skulls marked with 47 measuring points; reconstructed three-dimensional images; and measured the distances between the points in the 3D images with a computer-aided design/computer-aided manufacturing (CAD/CAM) marker. We found that in comparison with the helical CT, conebeam CT is capable of reproducing measurements closer to those obtained from the actual samples. In conclusion, our study indicated that the image-reproduction from a conebeam CT scan was more accurate than that from a helical CT scan. Furthermore, the "high-precision reconstructed 3D model" facilitates reliable visualization of full-sized oral and maxillofacial regions in both helical and conebeam CT scans.

  13. Dosimetric and workflow evaluation of first commercial synthetic CT software for clinical use in pelvis

    NASA Astrophysics Data System (ADS)

    Tyagi, Neelam; Fontenla, Sandra; Zhang, Jing; Cloutier, Michelle; Kadbi, Mo; Mechalakos, Jim; Zelefsky, Michael; Deasy, Joe; Hunt, Margie

    2017-04-01

    To evaluate a commercial synthetic CT (syn-CT) software for use in prostate radiotherapy. Twenty-five prostate patients underwent CT and MR simulation scans in treatment position on a 3T MR scanner. A commercially available MR protocol was used that included a T2w turbo spin-echo sequence for soft-tissue contrast and a dual echo 3D mDIXON fast field echo (FFE) sequence for generating syn-CT. A dual-echo 3D FFE B 0 map was used for patient-induced susceptibility distortion analysis and a new 3D balanced-FFE sequence was evaluated for identification of implanted gold fiducial markers and subsequent image-guidance during radiotherapy delivery. Tissues were classified as air, adipose, water, trabecular/spongy bone and compact/cortical bone and assigned bulk HU values. The accuracy of syn-CT for treatment planning was analyzed by transferring the structures and plan from planning CT to syn-CT and recalculating the dose. Accuracy of localization at the treatment machine was evaluated by comparing registration of kV radiographs to either digitally reconstructed radiographs (DRRs) generated from syn-CT or traditional DRRs generated from the planning CT. Similarly, accuracy of setup using CBCT and syn-CT was compared to that using the planning CT. Finally, a MR-only simulation workflow was established and end-to-end testing was completed on five patients undergoing MR-only simulation. Dosimetric comparison between the original CT and syn-CT plans was within 0.5% on average for all structures. The de-novo optimized plans on the syn-CT met institutional clinical objectives for target and normal structures. Patient-induced susceptibility distortion based on B 0 maps was within 1 mm and 0.5 mm in the body and prostate respectively. DRR and CBCT localization based on MR-localized fiducials showed a standard deviation of  <1 mm. End-to-end testing and MR simulation workflow was successfully validated. MRI derived synthetic CT can be successfully used for a MR

  14. CT angiography - arms and legs

    MedlinePlus

    ... combines a CT scan with the injection of dye. This technique is able to create pictures of ... Some exams require a special dye, called contrast, to be injected into your body before the test. Contrast helps certain areas show up better on the x- ...

  15. Pocket atlas of normal CT anatomy

    SciTech Connect

    Weinstein, J.B.; Lee, J.K.T.; Sagel, S.S.

    1985-01-01

    This book is a quick reference for interpreting CT scans of the extracranial organs. This collection of 41 CT scans covers all the major organs of the body: neck and larynx; chest; abdomen; male pelvis; and female pelvis.

  16. TU-G-BRA-02: Can We Extract Lung Function Directly From 4D-CT Without Deformable Image Registration?

    SciTech Connect

    Kipritidis, J; Woodruff, H; Counter, W; Keall, P; Hofman, M; Siva, S; Callahan, J; Le Roux, P; Hardcastle, N

    2015-06-15

    Purpose: Dynamic CT ventilation imaging (CT-VI) visualizes air volume changes in the lung by evaluating breathing-induced lung motion using deformable image registration (DIR). Dynamic CT-VI could enable functionally adaptive lung cancer radiation therapy, but its sensitivity to DIR parameters poses challenges for validation. We hypothesize that a direct metric using CT parameters derived from Hounsfield units (HU) alone can provide similar ventilation images without DIR. We compare the accuracy of Direct and Dynamic CT-VIs versus positron emission tomography (PET) images of inhaled {sup 68}Ga-labelled nanoparticles (‘Galligas’). Methods: 25 patients with lung cancer underwent Galligas 4D-PET/CT scans prior to radiation therapy. For each patient we produced three CT- VIs. (i) Our novel method, Direct CT-VI, models blood-gas exchange as the product of air and tissue density at each lung voxel based on time-averaged 4D-CT HU values. Dynamic CT-VIs were produced by evaluating: (ii) regional HU changes, and (iii) regional volume changes between the exhale and inhale 4D-CT phase images using a validated B-spline DIR method. We assessed the accuracy of each CT-VI by computing the voxel-wise Spearman correlation with free-breathing Galligas PET, and also performed a visual analysis. Results: Surprisingly, Direct CT-VIs exhibited better global correlation with Galligas PET than either of the dynamic CT-VIs. The (mean ± SD) correlations were (0.55 ± 0.16), (0.41 ± 0.22) and (0.29 ± 0.27) for Direct, Dynamic HU-based and Dynamic volume-based CT-VIs respectively. Visual comparison of Direct CT-VI to PET demonstrated similarity for emphysema defects and ventral-to-dorsal gradients, but inability to identify decreased ventilation distal to tumor-obstruction. Conclusion: Our data supports the hypothesis that Direct CT-VIs are as accurate as Dynamic CT-VIs in terms of global correlation with Galligas PET. Visual analysis, however, demonstrated that different CT

  17. Abdominal CT findings in small bowel perforation.

    PubMed

    Zissin, R; Osadchy, A; Gayer, G

    2009-02-01

    Small bowel perforation is an emergent medical condition for which the diagnosis is usually not made clinically but by CT, a common imaging modality used for the diagnosis of acute abdomen. Direct CT features that suggest perforation include extraluminal air and oral contrast, which are often associated with secondary CT signs of bowel pathology. This pictorial review illustrates the CT findings of small bowel perforation caused by various clinical entities.

  18. CT Scans - Multiple Languages: MedlinePlus

    MedlinePlus

    ... الأشعة المقطعية الحاسوبية - العربية Bilingual PDF Health Information Translations Chinese - Simplified (简体中文) CT (Computerized Tomography) Scan CT ( ... 扫描 - 简体中文 (Chinese - Simplified) Bilingual PDF Health Information Translations Chinese - Traditional (繁體中文) CT (Computerized Tomography) Scan CT ( ...

  19. Medipix3 CT for material sciences

    NASA Astrophysics Data System (ADS)

    Procz, S.; Wartig, K.-A.; Fauler, A.; Zwerger, A.; Luebke, J.; Ballabriga, R.; Blaj, G.; Campbell, M.; Mix, M.; Fiederle, M.

    2013-01-01

    Innovative detector systems for non-destructive material analysis and for medical diagnosis are an important development to improve the performance and the quality of examination methods. For a number of years now photon-counting X-ray detectors are being developed to process incoming X-ray photons as single events. These detectors facilitate a higher signal-to-noise ratio (SNR) than conventional, non-photon-counting, scintillator based detector systems, which detect X-ray photons indirectly through conversion into visible light. The Medipix is a pixelated photon counting semiconductor detector which features adjustable energy thresholds allowing energy selective, multispectral X-ray imaging. The Medipix chip is under continued development by the ``Medipix2 Collaboration'' and ``Medipix3 Collaboration'' at CERN [1]. The Medipix electronic offers 256 × 256 pixels with a pixel pitch of 55 × 55 μm2 and can be hybridized with different sensor materials like Si, CdTe or GaAs. The newest member of the Medipix family is the Medipix3 (ASIC in 0.13 μm CMOS technology) providing up to eight separate 12-bit counters per pixel. It offers a couple of different working modes [2], which are useful for X-ray imaging applications. A Medipix3 CT X-ray measuring station was built up for small animal X-ray imaging and non-destructive material analysis [3]. The combination of the low energy threshold ( ~ 4 keV) of the Medipix3 with its multispectral capability enables tomographic investigations on objects with low absorption contrast. The advantage of photon counting, multispectral detectors like Medipix3 for material sciences will be presented here as well as a comparison with a scintillator based CT.

  20. Micro-CT Technique Is Well Suited for Documentation of Remodeling Processes in Murine Carotid Arteries

    PubMed Central

    Schürmann, Christoph; Gremse, Felix; Jo, Hanjoong; Kiessling, Fabian; Brandes, Ralf P.

    2015-01-01

    Background The pathomechanisms of atherosclerosis and vascular remodelling are under intense research. Only a few in vivo tools to study these processes longitudinally in animal experiments are available. Here, we evaluated the potential of micro-CT technology. Methods Lumen areas of the common carotid arteries (CCA) in the ApoE-/- partial carotid artery ligation mouse model were compared between in vivo and ex vivo micro-CT technique and serial histology in a total of 28 animals. AuroVist-15 nm nanoparticles were used as in vivo blood pool contrast agent in a Skyscan 1176 micro-CT at resolution of 18 μmeter voxel size and a mean x-ray dose of 0.5 Gy. For ex vivo imaging, animals were perfused with MicroFil and imaged at 9 μmeter voxel size. Lumen area was evaluated at postoperative days 7, 14, and 28 first by micro-CT followed by histology. Results In vivo micro-CT and histology revealed lumen loss starting at day 14. The lumen profile highly correlated (r = 0.79, P<0.0001) between this two methods but absolute lumen values obtained by histology were lower than those obtained by micro-CT. Comparison of in vivo and ex vivo micro-CT imaging revealed excellent correlation (r = 0.83, P<0.01). Post mortem micro-CT yielded a higher resolution than in vivo micro-CT but there was no statistical difference of lumen measurements in the partial carotid artery ligation model. Conclusion These data demonstrate that in vivo micro-CT is a feasible and accurate technique with low animal stress to image remodeling processes in the murine carotid artery. PMID:26086218

  1. Study on Neurological Manifestations of Eclampsia & Findings of CT scan of Brain.

    PubMed

    Begum, F; Nahar, K; Ahmed, M U; Ferdousi, R A; Akter, F A; Rahman, M M

    2015-10-01

    This cross sectional study was carried out in the Department of Obstetrics & Gynaecology in Mymensingh Medical College Hospital during the period of January 2011 to December 2012 to evaluate neurological manifestations in eclampsia by CT scan of brain. A total 35 patients with eclampsia were studied, who underwent CT scan of brain in Radiology & Imaging Department of Mymensingh Medical College Hospital. The study patients were divided into two groups, those who had changes in brain on CT scan (Group A) & those who had no changes in brain on CT scan (Group B). Finally the study variables were compared between these two groups. Each selected patient fulfilling the criteria was sent to the department of Radiology & Imaging for CT scanning of brain. In antepartum cases of eclampsia CT scan of brain were done after delivery/ termination of pregnancy. In all cases, CT scan of brain was done within 72 hours of admission. Out of 35 patients total 85.72% had changes in brain on CT scan & 14.28% had no changes in brain on CT scan. Among them 45.72% patients had cerebral oedema, 37.14% had cerebral infarct & 2.86% patients had intracerebral haemorrhage. Comparison of neurological parameters were done & showed that there were statistically significant difference between the two groups regarding headache, visual disturbance, hypereflexia & depression of consciousness. There was no statistically significant difference regarding aphasia & hemiplegia between the two groups. So the CT scan of brain has been useful in demonstrating the lesion of brain in patients with eclampsia & also helpful to evaluate the neurological manifestations in eclampsia.

  2. SU-E-I-73: Clinical Evaluation of CT Image Reconstructed Using Interior Tomography

    SciTech Connect

    Zhang, J; Ge, G; Winkler, M; Cong, W; Wang, G

    2014-06-01

    Purpose: Radiation dose reduction has been a long standing challenge in CT imaging of obese patients. Recent advances in interior tomography (reconstruction of an interior region of interest (ROI) from line integrals associated with only paths through the ROI) promise to achieve significant radiation dose reduction without compromising image quality. This study is to investigate the application of this technique in CT imaging through evaluating imaging quality reconstructed from patient data. Methods: Projection data were directly obtained from patients who had CT examinations in a Dual Source CT scanner (DSCT). Two detectors in a DSCT acquired projection data simultaneously. One detector provided projection data for full field of view (FOV, 50 cm) while another detectors provided truncated projection data for a FOV of 26 cm. Full FOV CT images were reconstructed using both filtered back projection and iterative algorithm; while interior tomography algorithm was implemented to reconstruct ROI images. For comparison reason, FBP was also used to reconstruct ROI images. Reconstructed CT images were evaluated by radiologists and compared with images from CT scanner. Results: The results show that the reconstructed ROI image was in excellent agreement with the truth inside the ROI, obtained from images from CT scanner, and the detailed features in the ROI were quantitatively accurate. Radiologists evaluation shows that CT images reconstructed with interior tomography met diagnosis requirements. Radiation dose may be reduced up to 50% using interior tomography, depending on patient size. Conclusion: This study shows that interior tomography can be readily employed in CT imaging for radiation dose reduction. It may be especially useful in imaging obese patients, whose subcutaneous tissue is less clinically relevant but may significantly increase radiation dose.

  3. SU-E-J-120: Comparing 4D CT Computed Ventilation to Lung Function Measured with Hyperpolarized Xenon-129 MRI

    SciTech Connect

    Neal, B; Chen, Q

    2015-06-15

    Purpose: To correlate ventilation parameters computed from 4D CT to ventilation, profusion, and gas exchange measured with hyperpolarized Xenon-129 MRI for a set of lung cancer patients. Methods: Hyperpolarized Xe-129 MRI lung scans were acquired for lung cancer patients, before and after radiation therapy, measuring ventilation, perfusion, and gas exchange. In the standard clinical workflow, these patients also received 4D CT scans before treatment. Ventilation was computed from 4D CT using deformable image registration (DIR). All phases of the 4D CT scan were registered using a B-spline deformable registration. Ventilation at the voxel level was then computed for each phase based on a Jacobian volume expansion metric, yielding phase sorted ventilation images. Ventilation based upon 4D CT and Xe-129 MRI were co-registered, allowing qualitative visual comparison and qualitative comparison via the Pearson correlation coefficient. Results: Analysis shows a weak correlation between hyperpolarized Xe-129 MRI and 4D CT DIR ventilation, with a Pearson correlation coefficient of 0.17 to 0.22. Further work will refine the DIR parameters to optimize the correlation. The weak correlation could be due to the limitations of 4D CT, registration algorithms, or the Xe-129 MRI imaging. Continued development will refine parameters to optimize correlation. Conclusion: Current analysis yields a minimal correlation between 4D CT DIR and Xe-129 MRI ventilation. Funding provided by the 2014 George Amorino Pilot Grant in Radiation Oncology at the University of Virginia.

  4. Filtered back-projection reconstruction for attenuation proton CT along most likely paths.

    PubMed

    Quiñones, C T; Létang, J M; Rit, S

    2016-05-07

    This work investigates the attenuation of a proton beam to reconstruct the map of the linear attenuation coefficient of a material which is mainly caused by the inelastic interactions of protons with matter. Attenuation proton computed tomography (pCT) suffers from a poor spatial resolution due to multiple Coulomb scattering (MCS) of protons in matter, similarly to the conventional energy-loss pCT. We therefore adapted a recent filtered back-projection algorithm along the most likely path (MLP) of protons for energy-loss pCT (Rit et al 2013) to attenuation pCT assuming a pCT scanner that can track the position and the direction of protons before and after the scanned object. Monte Carlo simulations of pCT acquisitions of density and spatial resolution phantoms were performed to characterize the new algorithm using Geant4 (via Gate). Attenuation pCT assumes an energy-independent inelastic cross-section, and the impact of the energy dependence of the inelastic cross-section below 100 MeV showed a capping artifact when the residual energy was below 100 MeV behind the object. The statistical limitation has been determined analytically and it was found that the noise in attenuation pCT images is 411 times and 278 times higher than the noise in energy-loss pCT images for the same imaging dose at 200 MeV and 300 MeV, respectively. Comparison of the spatial resolution of attenuation pCT images with a conventional straight-line path binning showed that incorporating the MLP estimates during reconstruction improves the spatial resolution of attenuation pCT. Moreover, regardless of the significant noise in attenuation pCT images, the spatial resolution of attenuation pCT was better than that of conventional energy-loss pCT in some studied situations thanks to the interplay of MCS and attenuation known as the West-Sherwood effect.

  5. Filtered back-projection reconstruction for attenuation proton CT along most likely paths

    NASA Astrophysics Data System (ADS)

    Quiñones, C. T.; Létang, J. M.; Rit, S.

    2016-05-01

    This work investigates the attenuation of a proton beam to reconstruct the map of the linear attenuation coefficient of a material which is mainly caused by the inelastic interactions of protons with matter. Attenuation proton computed tomography (pCT) suffers from a poor spatial resolution due to multiple Coulomb scattering (MCS) of protons in matter, similarly to the conventional energy-loss pCT. We therefore adapted a recent filtered back-projection algorithm along the most likely path (MLP) of protons for energy-loss pCT (Rit et al 2013) to attenuation pCT assuming a pCT scanner that can track the position and the direction of protons before and after the scanned object. Monte Carlo simulations of pCT acquisitions of density and spatial resolution phantoms were performed to characterize the new algorithm using Geant4 (via Gate). Attenuation pCT assumes an energy-independent inelastic cross-section, and the impact of the energy dependence of the inelastic cross-section below 100 MeV showed a capping artifact when the residual energy was below 100 MeV behind the object. The statistical limitation has been determined analytically and it was found that the noise in attenuation pCT images is 411 times and 278 times higher than the noise in energy-loss pCT images for the same imaging dose at 200 MeV and 300 MeV, respectively. Comparison of the spatial resolution of attenuation pCT images with a conventional straight-line path binning showed that incorporating the MLP estimates during reconstruction improves the spatial resolution of attenuation pCT. Moreover, regardless of the significant noise in attenuation pCT images, the spatial resolution of attenuation pCT was better than that of conventional energy-loss pCT in some studied situations thanks to the interplay of MCS and attenuation known as the West-Sherwood effect.

  6. Disease identification based on ambulatory drugs dispensation and in-hospital ICD-10 diagnoses: a comparison

    PubMed Central

    2013-01-01

    Background Pharmacy-based case mix measures are an alternative source of information to the relatively scarce outpatient diagnoses data. But most published tools use national drug nomenclatures and offer no head-to-head comparisons between drugs-related and diagnoses-based categories. The objective of the study was to test the accuracy of drugs-based morbidity groups derived from the World Health Organization Anatomical Therapeutic Chemical Classification of drugs by checking them against diagnoses-based groups. Methods We compared drugs-based categories with their diagnoses-based analogues using anonymous data on 108,915 individuals insured with one of four companies. They were followed throughout 2005 and 2006 and hospitalized at least once during this period. The agreement between the two approaches was measured by weighted kappa coefficients. The reproducibility of the drugs-based morbidity measure over the 2 years was assessed for all enrollees. Results Eighty percent used a drug associated with at least one of the 60 morbidity categories derived from drugs dispensation. After accounting for inpatient under-coding, fifteen conditions agreed sufficiently with their diagnoses-based counterparts to be considered alternative strategies to diagnoses. In addition, they exhibited good reproducibility and allowed prevalence estimates in accordance with national estimates. For 22 conditions, drugs-based information identified accurately a subset of the population defined by diagnoses. Conclusions Most categories provide insurers with health status information that could be exploited for healthcare expenditure prediction or ambulatory cost control, especially when ambulatory diagnoses are not available. However, due to insufficient concordance with their diagnoses-based analogues, their use for morbidity indicators is limited. PMID:24171918

  7. The role of adalimumab in rheumatic and autoimmune disorders: comparison with other biologic agents

    PubMed Central

    Reimold, Andreas M

    2012-01-01

    Adalimumab (ADA) is a biologic medication that dampens inflammatory pathways by binding to the cytokine tumor necrosis factor alpha. The US Food and Drug Administration has approved ADA as a medication for use in rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, Crohn’s disease, psoriasis, and juvenile idiopathic arthritis. This year marks 10 years of clinical experience with ADA. Long-term extension studies of some of the initial clinical trials, as well as data from large patient registries, are demonstrating ongoing benefit for responders. Potential side effects such as increased risk of infection, lymphoma, congestive heart failure, and demyelination continue to be examined, as the available data are not unanimous in showing an increase in incidence. In balancing both the advantages and the disadvantages of using ADA, the drug’s overall effectiveness and its availability for use in patients with hepatic or renal comorbidities are weighed against the high cost. ADA is expected to have a leading role in the treatment of rheumatoid arthritis and other inflammatory conditions for years to come. Future studies will need to address the optimal sequence of disease-modifying antirheumatic drugs and biologics to use, combinations of disease-modifying antirheumatic drugs and biologics, and head-to-head comparisons of biologics in clinical trials. For those who go into clinical remission on an anti-tumor necrosis factor medication, unanswered questions remain about identifying the patients who can maintain the remission off all drugs, or at least off injected medication. Given the cost of biologic drugs, even studies that increase the interval between drug doses in well-controlled patients could provide financial benefits. PMID:27790010

  8. Cervical tuberculous adenitis: CT manifestations

    SciTech Connect

    Reede, D.L.; Bergeron, R.T.

    1985-03-01

    Cervical tuberculous adenitis is being seen with increasing frequency in the United States; in the appropriate clinical setting it should be included in the differential diagnosis of an asymptomatic neck mass. Patients are typically young adults who are recent arrivals from Southeast Asia. A history of tuberculosis is not always elicited nor is the chest radiograph always abnormal. All of these patients have positive purified protein derivative tests unless they are anergic. The CT findings may lead to the diagnosis. Several CT patterns of nodal disease can be seen in tuberculous adenitis; some may mimic benign and neoplastic disease. The presence of a multiloculated or multichambered (conglomerate nodal) mass with central lucency and thick rims of enhancement and minimally effaced fascial planes is highly suggestive of tuberculous adenitis, especially if the patient has a strongly positive tuberculosis skin test.

  9. Dual energy CT for attenuation correction with PET/CT

    SciTech Connect

    Xia, Ting; Alessio, Adam M.; Kinahan, Paul E.

    2014-01-15

    Purpose: The authors evaluate the energy dependent noise and bias properties of monoenergetic images synthesized from dual-energy CT (DECT) acquisitions. These monoenergetic images can be used to estimate attenuation coefficients at energies suitable for positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging. This is becoming more relevant with the increased use of quantitative imaging by PET/CT and SPECT/CT scanners. There are, however, potential variations in the noise and bias of synthesized monoenergetic images as a function of energy. Methods: The authors used analytic approximations and simulations to estimate the noise and bias of synthesized monoenergetic images of water-filled cylinders with different shapes and the NURBS-based cardiac-torso (NCAT) phantom from 40 to 520 keV, the range of SPECT and PET energies. The dual-kVp spectra were based on the GE Lightspeed VCT scanner at 80 and 140 kVp with added filtration of 0.5 mm Cu. The authors evaluated strategies of noise suppression with sinogram smoothing and dose minimization with reduction of tube currents at the two kVp settings. The authors compared the impact of DECT-based attenuation correction with single-kVp CT-based attenuation correction on PET quantitation for the NCAT phantom for soft tissue and high-Z materials of bone and iodine contrast enhancement. Results: Both analytic calculations and simulations displayed the expected minimum noise value for a synthesized monoenergetic image at an energy between the mean energies of the two spectra. In addition the authors found that the normalized coefficient of variation in the synthesized attenuation map increased with energy but reached a plateau near 160 keV, and then remained constant with increasing energy up to 511 keV and beyond. The bias was minimal, as the linear attenuation coefficients of the synthesized monoenergetic images were within 2.4% of the known true values across the entire energy range

  10. Ultra-low dose CT attenuation correction for PET/CT

    NASA Astrophysics Data System (ADS)

    Xia, Ting; Alessio, Adam M.; De Man, Bruno; Manjeshwar, Ravindra; Asma, Evren; Kinahan, Paul E.

    2012-01-01

    A challenge for positron emission tomography/computed tomography (PET/CT) quantitation is patient respiratory motion, which can cause an underestimation of lesion activity uptake and an overestimation of lesion volume. Several respiratory motion correction methods benefit from longer duration CT scans that are phase matched with PET scans. However, even with the currently available, lowest dose CT techniques, extended duration cine CT scans impart a substantially high radiation dose. This study evaluates methods designed to reduce CT radiation dose in PET/CT scanning. We investigated selected combinations of dose reduced acquisition and noise suppression methods that take advantage of the reduced requirement of CT for PET attenuation correction (AC). These include reducing CT tube current, optimizing CT tube voltage, adding filtration, CT sinogram smoothing and clipping. We explored the impact of these methods on PET quantitation via simulations on different digital phantoms. CT tube current can be reduced much lower for AC than that in low dose CT protocols. Spectra that are higher energy and narrower are generally more dose efficient with respect to PET image quality. Sinogram