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Sample records for computerized tomography comparison

  1. Computerized tomography calibrator

    NASA Technical Reports Server (NTRS)

    Engel, Herbert P. (Inventor)

    1991-01-01

    A set of interchangeable pieces comprising a computerized tomography calibrator, and a method of use thereof, permits focusing of a computerized tomographic (CT) system. The interchangeable pieces include a plurality of nestable, generally planar mother rings, adapted for the receipt of planar inserts of predetermined sizes, and of predetermined material densities. The inserts further define openings therein for receipt of plural sub-inserts. All pieces are of known sizes and densities, permitting the assembling of different configurations of materials of known sizes and combinations of densities, for calibration (i.e., focusing) of a computerized tomographic system through variation of operating variables thereof. Rather than serving as a phanton, which is intended to be representative of a particular workpiece to be tested, the set of interchangeable pieces permits simple and easy standardized calibration of a CT system. The calibrator and its related method of use further includes use of air or of particular fluids for filling various openings, as part of a selected configuration of the set of pieces.

  2. Comparison of ultrasonography, computerized tomography, and radionuclide imaging in the diagnosis of acute and chronic cholecystitis

    SciTech Connect

    Matolo, N.M.; Stadalnik, R.C.; McGahan, J.P.

    1982-12-01

    Seventy-five patients with abdominal pain in the right upper quadrant who were subsequently confirmed operatively and histologically to have acute or chronic cholecystitis underwent radionuclide imaging of the biliary tree, ultrasonography, and/or computerized tomography before operation. fifty-eight of the patients had acute cholecystitis and 17 had chronic cholecystitis and cholelithiasis. Analysis of our data indicates that ultrasonography is an accurate and better screening test than cholescintigraphy in the diagnosis of chronic cholecystitis and cholelithiasis, but it is less accurate in the detection of acute cholecystitis. On the other hand, radionuclide imaging is highly sensitive and specific in the early diagnosis of acute cholecystitis, but it is poor in the diagnosis of chronic cholecystitis and cholelithiasis unless the cystic duct is obstructed. CT scanning is more expensive than ultrasonography but may be extremely helpful in problematic cases such as the diagnosis of the cause in biliary obstruction or in imaging of the pancreas.

  3. Comparisons of ionospheric electron density distributions reconstructed by GPS computerized tomography, backscatter ionograms, and vertical ionograms

    NASA Astrophysics Data System (ADS)

    Zhou, Chen; Lei, Yong; Li, Bofeng; An, Jiachun; Zhu, Peng; Jiang, Chunhua; Zhao, Zhengyu; Zhang, Yuannong; Ni, Binbin; Wang, Zemin; Zhou, Xuhua

    2015-12-01

    Global Positioning System (GPS) computerized ionosphere tomography (CIT) and ionospheric sky wave ground backscatter radar are both capable of measuring the large-scale, two-dimensional (2-D) distributions of ionospheric electron density (IED). Here we report the spatial and temporal electron density results obtained by GPS CIT and backscatter ionogram (BSI) inversion for three individual experiments. Both the GPS CIT and BSI inversion techniques demonstrate the capability and the consistency of reconstructing large-scale IED distributions. To validate the results, electron density profiles obtained from GPS CIT and BSI inversion are quantitatively compared to the vertical ionosonde data, which clearly manifests that both methods output accurate information of ionopsheric electron density and thereby provide reliable approaches to ionospheric soundings. Our study can improve current understanding of the capability and insufficiency of these two methods on the large-scale IED reconstruction.

  4. Comparison between multislice and cone-beam computerized tomography in the volumetric assessment of cleft palate.

    PubMed

    Albuquerque, Marco Antonio; Gaia, Bruno Felipe; Cavalcanti, Marcelo Gusmão Paraíso

    2011-08-01

    The aim of this study was to determine the applicability of multislice and cone-beam computerized tomography (CT) in the assessment of bone defects in patients with oral clefts. Bone defects were produced in 9 dry skulls to mimic oral clefts. All defects were modeled with wax. The skulls were submitted to multislice and cone-beam CT. Subsequently, physical measurements were obtained by the Archimedes principle of water displacement of wax models. The results demonstrated that multislice and cone-beam CT showed a high efficiency rate and were considered to be effective for volumetric assessment of bone defects. It was also observed that both CT modalities showed excellent results with high reliability in the study of the volume of bone defects, with no difference in performance between them. The clinical applicability of our research has shown these CT modalities to be immediate and direct, and they is important for the diagnosis and therapeutic process of patients with oral cleft. Copyright © 2011 Mosby, Inc. All rights reserved.

  5. X-ray computerized tomography

    SciTech Connect

    Wellington, S.L.; Vinegar, H.J.

    1987-08-01

    Computerized tomography (CT) is a new radiological imaging technique that measures density and atomic composition inside opaque objects. A revolutionary advance in medical radiology since 1972, CT has only recently been applied in petrophysics and reservoir engineering. This paper discusses several petrophysical applications, including three-dimensional (3D) measurement of density and porosity; rock mechanics studies; correlation of core logs with well logs; characterization of mud invasion, fractures, and disturbed core; and quantification of complex mineralogies and sand/shale ratios. Reservoir engineering applications presented include fundamental studies of CO/sub 2/ displacement in cores, focussing on viscous fingering, gravity segregation, miscibility, and mobility control.

  6. Diagnostic value of multislice computerized tomography angiography for aortic dissection: A comparison with DSA

    PubMed Central

    Lu, Dong; Li, Cheng-Li; Lv, Wei-Fu; Ni, Ming; Deng, Ke-Xue; Zhou, Chun-Ze; Xiao, Jing-Kun; Zhang, Zhen-Feng; Zhang, Xing-Ming

    2017-01-01

    The aim of the present study was to compare multislice computed tomography angiography (MSCTA) and digital subtraction angiography (DSA) in the diagnosis of aortic dissection. In total, 49 patients with aortic lesions received enhanced computed tomography scanning, and three-dimensional (3D) images were reconstructed by volume rendering (VR), maximum intensity projection (MIP), multiplanar reformation (MPR) and curved planar reconstruction (CPR). The display rate of the entry tear site, intimal flap, true and false lumen from each reconstruction method was calculated. For 30 patients with DeBakey type III aortic dissection, the entry tear site and size of the first intimal flap, aortic maximum diameter at the orifice of left subclavian artery (LSCA), distance between the first entry tear site and the orifice of LSCA, and maximum diameter of aortic true and false lumens were measured prior to implantation of endovascular covered stent-grafts. Data obtained by MSCTA and DSA were then compared. For the entry tear site, MPR, CPR and VR provided a display rate of 95.92, 95.92 and 18.37%, respectively, and the display rate of the intimal flap was 100% in the three methods. MIP did not directly display the entry tear site and intimal flap. For true and false lumens, MPR, CPR, and VR showed a display rate of 100%, while MIP only provided a display rate of 67.35%. When MSCTA was compared with DSA, there was a significant difference in the display of entry site number and position (P<0.05), whereas no significant difference was shown in the measurement of aortic maximum diameter at the orifice of LSCA and the maximum diameter of true and false lumens (P>0.05). In conclusion, among the 3D post-processing reconstruction methods of MSCTA used, MPR and CPR were optimal, followed by VR, and MIP. MSCTA may be the preferable imaging method to diagnose aortic dissection and evaluate treatment of endovascular-covered stent-grafting, preoperatively. PMID:28352308

  7. Computerized axial tomography: the normal EMI scan.

    PubMed Central

    Gawler, J; Bull, J D; Du Boulay, G H; Marshall, J

    1975-01-01

    Computerized axial tomography using the EMI scanner as a new method of using x-rays in diagnosis. The technique displays intracranial and orbital structures in the transverse plane. The appearances of normal EMI Scans are described and correlated with cerebral and orbital anatomy seen in transverse section. Images PMID:1081587

  8. Calibrator Blocks For Computerized Tomography (CT)

    NASA Technical Reports Server (NTRS)

    Engel, H. Peter

    1990-01-01

    Sets of calibrator blocks developed for use with industrial computerized tomography (CT) systems. Set of blocks (or number of stacked sets of blocks) placed on object table of CT system and scanned in usual way. Blocks include holes of known size, shape, and location. Appearance of holes in output image of CT system used to verify operation of system.

  9. Methods of predicting visceral fat in Brazilian adults and older adults: a comparison between anthropometry and computerized tomography.

    PubMed

    Roriz, Anna Karla Carneiro; de Oliveira, Carolina Cunha; Moreira, Pricilla Almeida; Eickemberg, Michaela; Medeiros, Jairza Maria Barreto; Sampaio, Lílian Ramos

    2011-03-01

    Visceral adipose tissue (VAT) is linked with the metabolic consequences of obesity, being necessary the use alternative methods of predicting this type of fat, like anthropometry. The objective of this study was assess the performance of anthropometry in predicting visceral fat measured with computerized tomography in adults and older adults. Study transversal with 197 individuals underwent computerized tomography (CT) and anthropometry. The variables analized were: visceral adipose tissue area by CT, Sagittal Abdominal Diameter (SAD), Waist Circumference (WC) and Waist-Hip Ratio (WHR). A descriptive analysis, Pearson correlation and ROC curve were carried out. We observed Correlations higher than 0.7 (p = 0.000) between the SAD, WC and the VAT area were found in adult men and older men and in adult women. WHR displayed the least correlations. The most sensitive and specific SAD cut-off points were equal for all the men (Adults: 20.2 cm/Older adults: 20.2 cm) but different for the women (Adults: 21.0 cm; sens.: 83.3; spec.: 79.1/Older adults: 19.9 cm; sens.: 81.0; spec.:79.3). The WC cutoff points that identified a VAT area = 130 cm2 were 90.2 cm and 92.2 cm for men (adult men--sens.: 86.7; spec.: 86.1--and older men-sens.: 79.3; spec.: 77.8 -respectively), while for women the recorded values were 92.3 cm (adult women--sens.: 83.3; spec: 81.4) and 88.2 cm (older women--sens.:76.2; spec.: 69.0). This study showed that WC and SAD achieved the best performance in the identification of visceral fat considered at risk for the development of cardiometabolic diseases in adults and older adults.

  10. Computerized tomography in evaluation of hepatic neoplasms

    SciTech Connect

    Luna, R.F.; Resende, C.; Tishler, J.M.A.; Aldrete, J.S.; Shin, M.S.; Rubin, E.; Rahn, N.H.

    1984-08-01

    The authors reviewed their experience with computerized tomography (CT) of the abdomen in 212 patients with histologically documented liver neoplasms seen during a 30-month period. The CT findings in cavernous hemangioma and focal nodular hyperplasia were specific, and permitted accurate diagnosis of this lesion before biopsy. The CT appearance of all other lesions was variable. CT is useful in providing an accurate evaluation of the intrahepatic and extrahepatic extent of the neoplasm.

  11. [Computerized tomography and craniocerebral trauma].

    PubMed

    Richter, H P; Braun, V

    1993-11-01

    Computed tomography (CT) is now the standard neuroradiological examination for patients with major head injuries, although conventional X-ray of the skull should not be neglected. Whereas the latter only shows such skull pathology as fractures or intracranial air following a basal fracture, CT clearly visualizes intracranial pathology. It allows differentiation between haematoma and contusion, between localized oedema and generalized brain swelling; CT is therefore indicated in every patient with disturbed consciousness, focal neurological signs, and/or secondary clinical impairment, and also in all drunken patients with head injury. In a patient with impaired consciousness and focal neurological deficit the probability of a pathologic CT is 85%. An extracerebral haematoma is often present, which needs urgent evacuation. A modern, non-expensive communications system using a standard telephone line enables hospitals without a neurosurgical unit to send CT pictures that are difficult to interpret to a neurosurgeon and to discuss them on-line by telephone. This system has now been in operation for over 2 years and has improved the care of patients with head injury in our region. It is highly efficient and reliable and improves cooperation between distant hospitals. It also helps to avoid unnecessary transfers, which are not only expensive but may even harm a critically ill patient.

  12. Multislice computerized tomography angiography in the evaluation of intracranial aneurysms: a comparison with intraarterial digital subtraction angiography.

    PubMed

    Wintermark, Max; Uske, Antoine; Chalaron, Marc; Regli, Luca; Maeder, Philippe; Meuli, Reto; Schnyder, Pierre; Binaghi, Stefano

    2003-04-01

    The goal of this study was to assess the diagnostic accuracy of computerized tomography (CT) angiography performed with the aid of multislice technology (MSCT angiography) in the investigation of intracranial aneurysms, by comparing this method with intraarterial digital subtraction (IADS) angiography. Fifty consecutive adult patients, who successively underwent MSCT angiography (four rows) and IADS angiography of intracranial vessels, were prospectively identified. The MSCT angiography studies consisted of 1.25-mm slices, with 0.8-mm reconstruction intervals, a pitch of 0.75, and timing determined by a test bolus. Two neuroradiologists, who were blinded to the initial interpretation of the MSCT angiograms as well as to those of the IADS angiograms, independently reviewed the MSCT angiograms for the detection and characterization of intracranial aneurysms. Forty-nine intracranial aneurysms were identified in 40 patients; 33 of these lesions were responsible for subarachnoid hemorrhage. The sensitivity, specificity, and accuracy of MSCT angiography in the detection of intracranial aneurysms were 94.8, 95.2, and 94.9%, respectively, on a per-aneurysm basis and 99, 95.2, and 98.3%, respectively, on a per-patient basis. Interobserver agreement was 98%. There was an excellent correlation between aneurysm size assessed using MSCT angiography and that determined by IADS angiography (slope = 0.916, r = 0.877, p < 0.001); however, 2 mm stood as the cutoff size below which the sensitivity of MSCT angiography was statistically lower. That method displayed great accuracy in characterizing the morphological characteristics of the aneurysm. Multislice CT angiography is an accurate and robust noninvasive screening test for intracranial aneurysms. It performs better than that reported for single-slice CT angiography. Introduction of eight- and especially 16-row MSCT angiography will provide further progression through thinner slices, a lower pitch, and a purely arterial phase.

  13. Micro-computerized tomography assessment of fluorescence aided caries excavation (FACE) technology: comparison with three other caries removal techniques.

    PubMed

    Zhang, X; Tu, R; Yin, W; Zhou, X; Li, X; Hu, D

    2013-12-01

    The aim of this study was to determine the caries removal effectiveness (CRE) and minimal invasiveness potential (MIP) of four dentine caries removal methods. After carious molars were scanned using micro-computerized tomography (micro-CT), dentine caries were removed by fluorescence aided caries excavation (FACE) technology, laser induced fluorescence (LIF), chemomechanical excavation (CME), and conventional excavation (CE). Micro-CT was then repeated. CRE was determined based on the volume of residual caries/initial caries (RC/IC) and the mean mineral density (MD) at the cavity floor. MIP was determined by measuring the volume of the prepared cavity/initial cavity (PC/IC). Among the four groups, the LIF group had the smallest RC/IC (0.08), the highest mean MD at the cavity floor (1.32 g/cm(3) ) and the highest MIP (4.47). The CME group had the highest RC/IC (0.24), the lowest mean MD (1.01 g/cm(3) ) and the lowest MIP (2.23). The CE group exhibited a more acceptable CRE (RC/IC = 0.13, mean MD = 1.21 g/cm(3) ) but had a higher MIP (3.95). Both the CRE and MIP parameters of FACE technology were the second most acceptable (RC/IC = 0.12, mean MD = 1.13 g/cm(3) , MIP = 3.20) and did not differ significantly from the most acceptable. FACE is an effective caries removal technology for removing infected dentine without significantly increasing cavity size. © 2013 Australian Dental Association.

  14. [Diagnosis of toxic lesions of the brain using computerized tomography].

    PubMed

    Bushev, I I; Karpova, M N; Tskhovrebov, T M

    1990-01-01

    X-ray computerized tomography was used to examine the brain in 39 patients aged 14 to 39 years with different experience of using volatile narcotically acting substances. The discovered alterations make it possible to appraise the influence of toxic substances and the degree of brain atrophy, which attests to the diagnostic value of computerized tomography in patients with toxicomanias.

  15. Computerized tomography in acute and chronic pancreatitis

    SciTech Connect

    Kalmar, J.A.; Matthews, C.C.; Bishop, L.A.

    1984-11-01

    Modern imaging techniques have revolutionized the diagnostic evaluation of pancreatitis, primarily demonstrating its complications. Computerized tomography (CT) is a more sensitive method than ultrasonography and pancreatic ductography. A chart review revealed 214 patients at our hospital with a discharge diagnosis of pancreatitis. Sixty patients had CT for evaluation of possible complications. Only five scans were normal. Of 37 cases of acute pancreatitis, 92% demonstrated localized or diffuse enlargement, and 65% showed loss of pancreatic outline. Other frequent findings included thickening of perirenal fascia (49%), ileus (43%), edema of mesentery (35%), and inflammatory exudate (32%). Abscess and pseudocyst were each detected in 8% of cases. In chronic pancreatitis 65% of patients showed localized or diffuse pancreatic enlargement. Atrophy of the gland (30%), calcification (30%), pseudocyst (26%), and dilated pancreatic ducts (17%) were also seen. CT is effective in evaluating pancreatitis and its complications. 14 references, 5 figures, 2 tables.

  16. SPECT (Single-Photon Emission Computerized Tomography) Scan

    MedlinePlus

    SPECT scan Overview By Mayo Clinic Staff A single-photon emission computerized tomography (SPECT) scan lets your doctor analyze the function of some of your internal organs. A SPECT scan is a type of nuclear imaging test, ...

  17. Computerized ionospheric tomography based on geosynchronous SAR

    NASA Astrophysics Data System (ADS)

    Hu, Cheng; Tian, Ye; Dong, Xichao; Wang, Rui; Long, Teng

    2017-02-01

    Computerized ionospheric tomography (CIT) based on spaceborne synthetic aperture radar (SAR) is an emerging technique to construct the three-dimensional (3-D) image of ionosphere. The current studies are all based on the Low Earth Orbit synthetic aperture radar (LEO SAR) which is limited by long repeat period and small coverage. In this paper, a novel ionospheric 3-D CIT technique based on geosynchronous SAR (GEO SAR) is put forward. First, several influences of complex atmospheric environment on GEO SAR focusing are detailedly analyzed, including background ionosphere and multiple scattering effects (induced by turbulent ionosphere), tropospheric effects, and random noises. Then the corresponding GEO SAR signal model is constructed with consideration of the temporal-variant background ionosphere within the GEO SAR long integration time (typically 100 s to 1000 s level). Concurrently, an accurate total electron content (TEC) retrieval method based on GEO SAR data is put forward through subband division in range and subaperture division in azimuth, obtaining variant TEC value with respect to the azimuth time. The processing steps of GEO SAR CIT are given and discussed. Owing to the short repeat period and large coverage area, GEO SAR CIT has potentials of covering the specific space continuously and completely and resultantly has excellent real-time performance. Finally, the TEC retrieval and GEO SAR CIT construction are performed by employing a numerical study based on the meteorological data. The feasibility and correctness of the proposed methods are verified.

  18. Computerized tomography and skeletal density of coral skeletons

    NASA Astrophysics Data System (ADS)

    Bosscher, Hemmo

    1993-07-01

    In this paper I describe and discuss the use of medical X-ray computerized tomography (CT) in the study of coral skeletons. CT generates X-ray images along freely chosen sections through the skeleton and offers, as well, the possibility of density measurements based on X-ray attenuation. This method has been applied to measure the skeletal density of the Caribbean reef-building coral Montastrea annularis, from Curaçao, Netherlands Antilles. The observed, non-linear increase of skeletal density with depth can be attributed to decreasing photo-synthetic rates with increasing water depth. A comparison with extension rate measurements shows the inverse relationship between extension rate and skeletal density. CT proves to be aquick and non-destructive method to reveal growth structures (density banding) since it measures skeletal density.

  19. Computerized tomography using video recorded fluoroscopic images

    NASA Technical Reports Server (NTRS)

    Kak, A. C.; Jakowatz, C. V., Jr.; Baily, N. A.; Keller, R. A.

    1975-01-01

    A computerized tomographic imaging system is examined which employs video-recorded fluoroscopic images as input data. By hooking the video recorder to a digital computer through a suitable interface, such a system permits very rapid construction of tomograms.

  20. A retrospective radiographic evaluation of the anterior loop of the mental nerve: Comparison between panoramic radiography and cone beam computerized tomography

    PubMed Central

    Vujanovic-Eskenazi, Aleksandar; Valero-James, Jesus-Manuel; Sánchez-Garcés, María-Angeles

    2015-01-01

    Objectives: To compare the prevalence and the length of mental loop, measured with panoramic radiography (PR) and cone beam computerized tomography (CBCT). Material and Methods: PG and CBCT images where analyzed by a single calibrated examiner to determine the presence and the position of the mental foramen (MF), its distance to the lower mandible border, the anterior length of the mental loop (ML) and the bone quality in 82 PR and 82 CBCT. Results: ML was identified in 36.6 % of PR and 48.8 % of CBCT. PR showed a magnification of 1.87 when compared to CBCT. The mean of anterior extension of the inferior alveolar nerve and the distance to the inferior border of the mandible was higher for PR (2.8 mm, sd 0.91 mm on the PR , range 1.5 to 4.7 mm and 1.59, sd 0.9 on the CBCT ,range 0.4 to 4.0 mm) Conclusions: There is a magnification in PR images with respect to those of CBCT. The differences between CBCT and PR with regards to the identification and length of the ML are not statistically significant. Identification and accuracy measurements of ML did not depend on the bone quality. Considering that two dimensional imaging provides less accurate and reliable information regarding the anterior loop, a CBCT scan could be recommended when planning implant placement in the anterior region. Key words:Mental loop, mental nerve, mental canal, preoperative implant planning, panoramic tomography, cone beam computerized tomography. PMID:25549693

  1. Morphological analysis of the vestibular aqueduct by computerized tomography images.

    PubMed

    Marques, Sergio Ricardo; Smith, Ricardo Luiz; Isotani, Sadao; Alonso, Luís Garcia; Anadão, Carlos Augusto; Prates, José Carlos; Lederman, Henrique Manoel

    2007-01-01

    In the last two decades, advances in the computerized tomography (CT) field revise the internal and medium ear evaluation. Therefore, the aim of this study is to analyze the morphology and morphometric aspects of the vestibular aqueduct on the basis of computerized tomography images (CTI). Computerized tomography images of vestibular aqueducts were acquired from patients (n=110) with an age range of 1-92 years. Thereafter, from the vestibular aqueducts images a morphometric analysis was performed. Through a computerized image processing system, the vestibular aqueduct measurements comprised of its area, external opening, length and the distance from the vestibular aqueduct to the internal acoustic meatus. The morphology of the vestibular aqueduct may be funnel-shaped, filiform or tubular and the respective proportions were found to be at 44%, 33% and 22% in children and 21.7%, 53.3% and 25% in adults. The morphometric data showed to be of 4.86 mm(2) of area, 2.24 mm of the external opening, 4.73 mm of length and 11.88 mm of the distance from the vestibular aqueduct to the internal acoustic meatus, in children, and in adults it was of 4.93 mm(2), 2.09 mm, 4.44 mm, and 11.35 mm, respectively. Computerized tomography showed that the vestibular aqueduct presents high morphological variability. The morphometric analysis showed that the differences found between groups of children and adults or between groups of both genders were not statistically significant.

  2. Computerized axial tomography in neurologic disorders of children.

    PubMed

    Bachman, D S; Hodges, F J; Freeman, J M

    1977-03-01

    Computerized axial tomography offers major advantages over air encephalography and angiography for studies of neurologic disorders in children. The low morbidity and the ease of the procedure permit the accurate diagnosis of intracranial pathology in situations where more invasive procedures would not be undertaken. The techniques of the procedure and its uses and limitations are emphasized in a number of neurologic problems of children.

  3. Anti-3-[18F]FACBC Positron Emission Tomography-Computerized Tomography and 111In-Capromab Pendetide Single Photon Emission Computerized Tomography-Computerized Tomography for Recurrent Prostate Carcinoma: Results of a Prospective Clinical Trial

    PubMed Central

    Schuster, David M.; Nieh, Peter T.; Jani, Ashesh B.; Amzat, Rianot; Bowman, F. DuBois; Halkar, Raghuveer K.; Master, Viraj A.; Nye, Jonathon A.; Odewole, Oluwaseun A.; Osunkoya, Adeboye O.; Savir-Baruch, Bital; Alaei-Taleghani, Pooneh; Goodman, Mark M.

    2014-01-01

    Purpose We prospectively evaluated the amino acid analogue positron emission tomography radiotracer anti-3-[18F]FACBC compared to ProstaScint® (111In-capromab pendetide) single photon emission computerized tomography-computerized tomography to detect recurrent prostate carcinoma. Materials and Methods A total of 93 patients met study inclusion criteria who underwent anti-3-[18F]FACBC positron emission tomography-computerized tomography plus 111In-capromab pendetide single photon emission computerized tomography-computerized tomography for suspected recurrent prostate carcinoma within 90 days. Reference standards were applied by a multidisciplinary board. We calculated diagnostic performance for detecting disease. Results In the 91 of 93 patients with sufficient data for a consensus on the presence or absence of prostate/bed disease anti-3-[18F]FACBC had 90.2% sensitivity, 40.0% specificity, 73.6% accuracy, 75.3% positive predictive value and 66.7% negative predictive value compared to 111In-capromab pendetide with 67.2%, 56.7%, 63.7%, 75.9% and 45.9%, respectively. In the 70 of 93 patients with a consensus on the presence or absence of extraprostatic disease anti-3-[18F]FACBC had 55.0% sensitivity, 96.7% specificity, 72.9% accuracy, 95.7% positive predictive value and 61.7% negative predictive value compared to 111In-capromabpendetide with10.0%, 86.7%, 42.9%, 50.0% and 41.9%, respectively. Of 77 index lesions used to prove positivity histological proof was obtained in 74 (96.1%). Anti-3-[18F]FACBC identified 14 more positive prostate bed recurrences (55 vs 41) and 18 more patients with extraprostatic involvement (22 vs 4). Anti-3-[18F]FACBC positron emission tomography-computerized tomography correctly up-staged 18 of 70 cases (25.7%) in which there was a consensus on the presence or absence of extraprostatic involvement. Conclusions Better diagnostic performance was noted for anti-3-[18F]FACBC positron emission tomography-computerized tomography than for 111In

  4. Computerized tomography using a modified orthogonal tangent correction algorithm.

    PubMed

    Hsia, T C; Smith, S C; Lantz, B M

    1976-10-01

    A modified orthogonal tangent correction algorithm is presented for computerized tomography. The algorithm uses four X-rays scans spaced 45 degrees apart, to reconstruct a transverse axial image. The reconstruction procedure is interative in which image matrix elements are corrected by alternately matching the two sets of orthogonal scan data. The algorithm has been applied to phantom data as well as to video recorded fluoroscopic data.

  5. Computerized tomography with total variation and with shearlets

    NASA Astrophysics Data System (ADS)

    Garduño, Edgar; Herman, Gabor T.

    2017-04-01

    To reduce the x-ray dose in computerized tomography (CT), many constrained optimization approaches have been proposed aiming at minimizing a regularizing function that measures a lack of consistency with some prior knowledge about the object that is being imaged, subject to a (predetermined) level of consistency with the detected attenuation of x-rays. One commonly investigated regularizing function is total variation (TV), while other publications advocate the use of some type of multiscale geometric transform in the definition of the regularizing function, a particular recent choice for this is the shearlet transform. Proponents of the shearlet transform in the regularizing function claim that the reconstructions so obtained are better than those produced using TV for texture preservation (but may be worse for noise reduction). In this paper we report results related to this claim. In our reported experiments using simulated CT data collection of the head, reconstructions whose shearlet transform has a small ℓ 1-norm are not more efficacious than reconstructions that have a small TV value. Our experiments for making such comparisons use the recently-developed superiorization methodology for both regularizing functions. Superiorization is an automated procedure for turning an iterative algorithm for producing images that satisfy a primary criterion (such as consistency with the observed measurements) into its superiorized version that will produce results that, according to the primary criterion are as good as those produced by the original algorithm, but in addition are superior to them according to a secondary (regularizing) criterion. The method presented for superiorization involving the ℓ 1-norm of the shearlet transform is novel and is quite general: It can be used for any regularizing function that is defined as the ℓ 1-norm of a transform specified by the application of a matrix. Because in the previous literature the split Bregman algorithm is used

  6. Demonstration of lesions of cerebral toxoplasmosis by computerized tomography.

    PubMed Central

    Summerfield, G. P.

    1980-01-01

    A patient who was treated for 11 years with cytotoxic drugs for Hodgkin's disease developed cerebral toxoplasmosis. Discrete lesions including an occipital abscess were visualized in the brain by computerized tomography (CT). This permitted a brain biopsy to be taken but the appearances were non-specific. At post-mortem pseudocysts of Toxoplasma gondii were found in several sites within the CNS. The recognition of these CT appearances as being due to toxoplasmosis should in future prompt serological investigation and urgent treatment of this potentially curable condition, despite negative biopsy material. Images Fig. 1 Fig. 2 Fig. 3 PMID:7393789

  7. Identifying and classifying hyperostosis frontalis interna via computerized tomography.

    PubMed

    May, Hila; Peled, Nathan; Dar, Gali; Hay, Ori; Abbas, Janan; Masharawi, Youssef; Hershkovitz, Israel

    2010-12-01

    The aim of this study was to recognize the radiological characteristics of hyperostosis frontalis interna (HFI) and to establish a valid and reliable method for its identification and classification. A reliability test was carried out on 27 individuals who had undergone a head computerized tomography (CT) scan. Intra-observer reliability was obtained by examining the images three times, by the same researcher, with a 2-week interval between each sample ranking. The inter-observer test was performed by three independent researchers. A validity test was carried out using two methods for identifying and classifying HFI: 46 cadaver skullcaps were ranked twice via computerized tomography scans and then by direct observation. Reliability and validity were calculated using Kappa test (SPSS 15.0). Reliability tests of ranking HFI via CT scans demonstrated good results (K > 0.7). As for validity, a very good consensus was obtained between the CT and direct observation, when moderate and advanced types of HFI were present (K = 0.82). The suggested classification method for HFI, using CT, demonstrated a sensitivity of 84%, specificity of 90.5%, and positive predictive value of 91.3%. In conclusion, volume rendering is a reliable and valid tool for identifying HFI. The suggested three-scale classification is most suitable for radiological diagnosis of the phenomena. Considering the increasing awareness of HFI as an early indicator of a developing malady, this study may assist radiologists in identifying and classifying the phenomena.

  8. Characterization of flow in fractured tuff using computerized tomography

    SciTech Connect

    Felice, C.W.; Sharer, J.C.

    1991-09-01

    The objective of this effort was to demonstrate TerraTek`s capability to use X-ray computerized tomography (CT) to observe fluid flow down a fracture and rock matrix imbibition in a sample of Bandelier tuff. To accomplish the objective, a tuff sample 152.4 mm long and 50.8 mm in diameter was prepared. A portion of the sample was artificially fractured and coupled to a section of matrix material so that the fracture was not exposed. Water was flowed through the sample at five flow rates and CT scanning performed at set intervals during the flow. Cross sectional images and longitudinal reconstructions were built and saturation profiles calculated for the sample at each time interval at each flow rate. The results showed that for the test conditions, the fracture was not a primary pathway of fluid flow down the sample. Fluid flow was governed by the high imbibition capability of the rock matrix material.

  9. Digital balanced detection for fast optical computerized tomography

    NASA Astrophysics Data System (ADS)

    Hafiz, Rehan; Ozanyan, Krikor B.

    2006-10-01

    Analogue Balanced Photo-detection has found extensive usage in high- sensitivity small signal applications e.g. coherent heterodyne detection. It is particularly effective for laser intensity noise removal. Nevertheless, the high cost of the commercially available analogue systems makes them unsuitable for multi-channel applications, such as fast tomography. In this paper a flexible, scalable, inexpensive and compact solution for multi channel digital balanced detection is presented. The proposed system has two components: an analogue front-end, comprising a differential photodiode amplifier for minimizing the external interference noise, and a digital balanced noise remover. The latter component initially calculates a balancing factor (BF) from the average power ratio of the signal and reference photocurrents, measured with the object removed from the signal path. Three digital balancing algorithms (DBAx) are considered for subsequent processing. In DBA1, BF is directly used in real-time ratiometric calculations. In DBA2, the BF is adjusted in real time by monitoring the window-averaged power of the received photocurrents. In DBA3, first the baseline is removed using differentiation and then ratiometric detection is performed. Using the digital alternative only one measurement of the reference beam is necessary for single-source, multi-channel detection systems. The data from multiple channels are processed in parallel by pipelined hardware, configured as a state machine. The proposed system leads to a fast optical computerized tomography system using digital balanced detection.

  10. Percutaneous nephrolithotomy in pediatric patients: is computerized tomography a must?

    PubMed

    Gedik, Abdullah; Tutus, Ali; Kayan, Devrim; Yılmaz, Yakup; Bircan, Kamuran

    2011-02-01

    The aim of this study was to retrospectively evaluate the results of pediatric percutaneous nephrolithotomy (PNL) cases, and discuss the results and necessity of non-contrast computerized tomography (CT) in these cases. In all, 48 pediatric patients who underwent PNL were retrospectively evaluated. Before PNL, either intravenous urography or CT was performed. In all patients, we evaluated the PNL time, scopy time with stone burden, and complications. During the PNL procedure, we switched to open surgery in two cases: in one because of renal pelvis perforation and in the other because of transcolonic access. In one patient who was scheduled to undergo PNL, we performed open surgery, primarily because we detected a retrorenal colon with CT. The stone burden in 45 patients who underwent PNL was 445 ± 225 mm(2), the PNL time was 51 ± 23 min, and the scopy time was 6.1 ± 2.7 min. We removed nephrostomy tubes 1-4 days after the procedure. In two patients, 24 h after removal of nephrostomy tubes, we inserted double J stents because of prolonged urine extravasation from the tract. In all, 34 of the 45 patients were stone-free, 5 patients had clinically insignificant stone fragments, and 6 patients had residual stones. PNL is a safe and effective method in the treatment of pediatric patients with kidney stones. Clinical experience is the most important factor in obtaining stone-free results. CT should be performed in all pediatric patients in order to prevent colon perforation.

  11. A combined reconstruction algorithm for computerized ionospheric tomography

    NASA Astrophysics Data System (ADS)

    Wen, D. B.; Ou, J. K.; Yuan, Y. B.

    Ionospheric electron density profiles inverted by tomographic reconstruction of GPS derived total electron content TEC measurements has the potential to become a tool to quantify ionospheric variability and investigate ionospheric dynamics The problem of reconstructing ionospheric electron density from GPS receiver to satellite TEC measurements are formulated as an ill-posed discrete linear inverse problem A combined reconstruction algorithm of computerized ionospheric tomography CIT is proposed in this paper In this algorithm Tikhonov regularization theory TRT is exploited to solve the ill-posed problem and its estimate from GPS observation data is input as the initial guess of simultaneous iterative reconstruction algorithm SIRT The combined algorithm offer a more reasonable method to choose initial guess of SIRT and the use of SIRT algorithm is to improve the quality of the final reconstructed imaging Numerical experiments from the actual GPS observation data are used to validate the reliability of the method the reconstructed results show that the new algorithm works reasonably and effectively with CIT the overall reconstruction error reduces significantly compared to the reconstruction error of SIRT only or TRT only

  12. An alternative approach to computerized tomography (CT) in forensic pathology.

    PubMed

    Thomsen, Asser H; Jurik, Anne Grethe; Uhrenholt, Lars; Vesterby, Annie

    2009-01-10

    Computerized Tomography (CT) is used by some forensic pathology departments as a supplement to the forensic autopsy. Departments with a limited number of autopsies may find it relatively expensive to acquire and operate a CT-scanner. Furthermore, it requires a great deal of training and experience to interpret the radiological data. We are currently evaluating CT in order to decide whether the benefits match the efforts. In selected death-investigations the Department of Radiology at Aarhus University Hospital performs CT of the body on behalf of the Institute of Forensic Medicine at Aarhus University and a skilled radiologist interprets the data. We present our radiological findings in the 20 cases where we have used CT and compare them to the autopsy findings. The cases include fatalities from beatings, stabbings, gunshots, fires and traffic accidents. CT is an excellent tool for documenting and illustrating certain lesions, such as gunshot wounds and bone fractures, where we can obtain information that possibly would have been missed at the autopsy. We believe, however, that further research is required before we can recommend CT as a part of a standard forensic autopsy. The cooperation between forensic and radiological departments is a good approach for smaller forensic departments that insures a skilled interpretation without having to divert a lot of resources to equipment and training.

  13. Pore-network extraction from micro-computerized-tomography images.

    PubMed

    Dong, Hu; Blunt, Martin J

    2009-09-01

    Network models that represent the void space of a rock by a lattice of pores connected by throats can predict relative permeability once the pore geometry and wettability are known. Micro-computerized-tomography scanning provides a three-dimensional image of the pore space. However, these images cannot be directly input into network models. In this paper a modified maximal ball algorithm, extending the work of Silin and Patzek [D. Silin and T. Patzek, Physica A 371, 336 (2006)], is developed to extract simplified networks of pores and throats with parametrized geometry and interconnectivity from images of the pore space. The parameters of the pore networks, such as coordination number, and pore and throat size distributions are computed and compared to benchmark data from networks extracted by other methods, experimental data, and direct computation of permeability and formation factor on the underlying images. Good agreement is reached in most cases allowing networks derived from a wide variety of rock types to be used for predictive modeling.

  14. The study of compressive sampling in ultrasonic computerized tomography

    NASA Astrophysics Data System (ADS)

    Wang, Wentao; Wang, Chonghe; Bao, Yuequan; Li, Hui

    2015-04-01

    This paper proposes a novel and effective method in the field of Non-Destructive Evaluation (NDE). Traditional ultrasonic computerized tomography (UCT) is a heavy task to detect the damages in the object for the numerous measuring times and the huge cost of manual labor. However, utilizing the method proposed in this paper can effectively overcome this great disadvantage, the essence of the application of Compressive Sampling(CS) in the detection of the object is to selectively choose a small quantity of measuring path in the huge number of total measurements. Due to the sparsity of damages in concrete structure, the usage of CS is available. Firstly, we divide the object entirely into numerous grids in order to image the internal situation of the object respectively. Secondly, a measurement matrix to massively decline the quantity of the measuring time should be computed. Thirdly, the travel time of each path we selected according to the matrix should be acquired, utilizing these travel time by adopting the l1-minimization program can we consequently obtained the slowness of the elements inside the object, thus reconstruct the internal situation of the object clearly and effectively. Furthermore, by applying this method we proposed in this paper into the simulation we can not only determine the damage location but also figure the size of it out. Because of the massive decline of the measuring times and accurate reconstruction, we substantiate CS method applied into the monitoring of concrete structure proves to be a shortcut in the field of NDE.

  15. Craniofacial findings in fibrodysplasia ossificans progressiva: computerized tomography evaluation.

    PubMed

    Carvalho, Daniel Rocha; Farage, Luciano; Martins, Bernardo Jose Alves Ferreira; Speck-Martins, Carlos Eduardo

    2011-04-01

    The aim of this study was the evaluation by using computerized tomography (CT) of craniofacial abnormalities in fibrodysplasia ossificans progressiva (FOP) patients regarding jaw restriction and retrognathia. Seven FOP patients were evaluated retrospectively in this observational study. Inclusion criteria were detection of ACVR1 gene mutation and complete craniofacial CT examination. The age of jaw restriction and presence of retrognathia were clinically determined. The features analyzed were skull base structures and heterotopic ossification (HO). Of this group (age range 4-23 years), the 3 oldest patients presented with jaw restriction and retrognathia as well as displayed elongation of the lateral pterygoid plate with HO of the pterygoid muscles that reached the medial surface of the right mandibular ramus. They had significant history of trauma or surgery. The other 4 patients did not have retrognathia or HO involving the facial or masticatory muscles, and the mouth opening was normal. CT evaluation can reveal HO of the pterygoid muscles that probably may cause jaw restriction and retrognathia in older FOP patients. Copyright © 2011 Mosby, Inc. All rights reserved.

  16. Vertebral sarcoidosis: demonstration of bone involvement by computerized axial tomography

    SciTech Connect

    Dinerstein, S.L.; Kovarsky, J.

    1984-08-01

    A report is given of a rare case of vertebral sarcoidosis with negative conventional spinal x-ray films, yet with typical cystic lesions of the spine found incidentally during abdominal computerized axial tomography (CAT). The patient was a 28-year-old black man, who was admitted for evaluation of a 1 1/2-year history of diffuse myalgias, intermittent fever to 102 F orally, bilateral hilar adenopathy, and leukopenia. A technetium polyphosphate bone scan revealed diffuse areas of increased uptake over the sternum, entire vertebral column, and pelvis. Conventional x-ray films of the cervical, thoracic, and lumbar spine, and an AP view of the pelvis were all normal. Chest x-ray film revealed only bilateral hilar adenopathy. During the course of an extensive negative evaluation for infection, an abdominal CAT scan was done, showing multiple, small, sclerotic-rimmed cysts at multiple levels of the lower thoracic and lumbar spine. Bone marrow biopsy revealed only changes consistent with anemia of chronic disease. Mediastinal lymph node biopsy revealed noncaseating granulomas. A tentative diagnosis of sarcoidosis was made, and treatment with prednisone, isoniazid and rifampin was begun. Within two weeks of initiation of prednisone therapy, the patient was symptom-free. A repeat technetium polyphosphate bone scan revealed only a small residual area of mildly increased uptake over the upper thoracic vertebrae.

  17. Fragility of brushite stones in shock wave lithotripsy: absence of correlation with computerized tomography visible structure.

    PubMed

    Williams, James C; Hameed, Tariq; Jackson, Molly E; Aftab, Syed; Gambaro, Alessia; Pishchalnikov, Yuri A; Lingeman, James E; McAteer, James A

    2012-09-01

    Brushite stones were imaged in vitro and then broken with shock wave lithotripsy to assess whether stone fragility correlates with internal stone structure visible on helical computerized tomography. A total of 52 brushite calculi were scanned by micro computerized tomography, weighed, hydrated and placed in a radiological phantom. Stones were scanned using a Philips® Brilliance iCT 256 system and images were evaluated for the visibility of internal structural features. The calculi were then treated with shock wave lithotripsy in vitro. The number of shock waves needed to break each stone to completion was recorded. The number of shock waves needed to break each stone normalized to stone weight did not differ by HU value (p = 0.84) or by computerized tomography visible structures that could be identified consistently by all observers (p = 0.053). Stone fragility correlated highly with stone density and brushite content (each p <0.001). Calculi of almost pure brushite required the most shock waves to break. When all observations of computerized tomography visible structures were used for analysis by logistic fit, computerized tomography visible structure predicted increased stone fragility with an overall area under the ROC curve of 0.64. The shock wave lithotripsy fragility of brushite stones did not correlate with internal structure discernible on helical computerized tomography. However, fragility did correlate with stone density and increasing brushite mineral content, consistent with clinical experience with patients with brushite calculi. Thus, current diagnostic computerized tomography technology does not provide a means to predict when brushite stones will break well using shock wave lithotripsy. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  18. [Importance of computerized tomography for surgical treatment of intracranial hematomas (author's transl)].

    PubMed

    Diemath, H E

    1982-03-31

    The improved treatment by using computerized tomography (CT) located between operating theater and intensive care unit is reported in comparison of 3,382 patients with severe head injuries. By preoperative use of CT the frequency of diagnosed hematomas was about the same (29.5% before CT; 27.0% with CT) but the preoperative diagnosed multiple hematomas were much more frequent (14.0% resp. 27.0%). The most important advantage however is the saving of time by CT in this localisation by which the chance of survival has increased from 54% to 69%. Without any doubt everywhere in neurotraumatology the CT should be situated as near as possible to the intensive care unit and to the operating theater and should be available 24 hours a day.

  19. Computerized tomography-based anatomic description of the porcine liver.

    PubMed

    Bekheit, Mohamed; Bucur, Petru O; Wartenberg, Mylene; Vibert, Eric

    2017-04-01

    The knowledge of the anatomic features is imperative for successful modeling of the different surgical situations. This study aims to describe the anatomic features of the porcine using computerized tomography (CT) scan. Thirty large, white, female pigs were included in this study. The CT image acquisition was performed in four-phase contrast study. Subsequently, analysis of the images was performed using syngo.via software (Siemens) to subtract mainly the hepatic artery and its branches. Analysis of the portal and hepatic veins division pattern was performed using the Myrian XP-Liver 1.14.1 software (Intrasense). The mean total liver volume was 915 ± 159 mL. The largest sector in the liver was the right medial one representing around 28 ± 5.7% of the total liver volume. Next in order is the right lateral sector constituting around 24 ± 5%. Its volume is very close to the volume of the left medial sector, which represents around 22 ± 4.7% of the total liver volume. The caudate lobe represents around 8 ± 2% of the total liver volume.The portal vein did not show distinct right and left divisions rather than consecutive branches that come off the main trunk. The hepatic artery frequently trifurcates into left trunk that gives off the right gastric artery and the artery to the left lateral sector, the middle hepatic artery that supplies both the right and the left medial sectors and the right hepatic artery trunk that divides to give anterior branch to the right lateral lobe, branch to the right medial lobe, and at least a branch to the caudate lobe. Frequently, there is a posterior branch that crosses behind the portal vein to the right lateral lobe. The suprahepatic veins join the inferior vena cava in three distinct openings. There are communications between the suprahepatic veins that drain the adjacent sectors. The vein from the right lateral and the right medial sectors drains into a common trunk. The vein from the left lateral and from the left

  20. [Image reconstruction of computerized tomography pictures using functional algebra].

    PubMed

    Bradaczek, M; Bradaczek, H

    1997-07-01

    A detailed presentation of the process for calculating computed tomograms from the measured data by means of functional algebra is given and an attempt is made to demonstrate the relationships to those inexperienced in mathematics. Suggestions are also made to the manufacturers for improving tomography software although the authors cannot exclude the possibility that some of the recommendations may have already been realized. An interpolation in Fourier space to right-angled coordinates was not employed so that additional computer time and errors resulting from the interpolation are avoided. The savings in calculation time can only be estimated but should amount to about 25%. The error-correction calculation is merely a suggestion since it depends considerably on the apparatus used. Functional algebra is introduced here because it is not so well known but does provide appreciable simplifications in comparison to an explicit presentation. Didactic reasons as well as the possibility for reducing calculation time provided the foundation for this work.

  1. Three-dimensional computerized tomography: a quantum leap in diagnostic imaging?

    PubMed

    Morrison, R; McCarty, J; Cushing, F R

    1994-01-01

    Ever since the discovery of radium by Madame Curie, men and women of vision and science have labored to improve radiation technology. Over a period of approximately 85 years, we have gone from this initial discovery to three-dimensional computerized transmission tomography; one of the latest techniques in modern day x-ray imaging. Its uses are vast and unparalleled in many facets of medicine and surgery, outlining pathology as never before seen, and possibly, never before completely understood. Three-dimensional computerized tomography is rapidly gaining popularity in cross-sectional imaging of the foot and ankle. It has proven invaluable in elucidating osseous and soft tissue pathology. Abnormalities of the musculoskeletal system that exhibit complex anatomy are often difficult to interpret using standard radiographic techniques. Overall, three-dimensional computerized tomography has established itself as a means by which clinicians may appreciate the three-dimensional disposition of anatomy and disease.

  2. Why is high resolution computerized tomography scanning used in evaluating the lungs?

    PubMed Central

    Graves, W. A.; Collins, J. D.; Miller, T. Q.

    1989-01-01

    High resolution computerized tomography scans have been used for medical and legal purposes to evaluate patients with a history of exposure to asbestos. Some investigators argue that high resolution scanning provides a better image of the lungs than routine computerized tomography. A review of the literature shows that although high resolution scanning displays the lymphatics in the lung, it offers no new useful diagnostic information. The authors conclude that no real advantage is attained with high resolution scanning of the lung and that pathology of disease can be determined decisively only by histology. Images Figure 1 Figure 2A Figure 2B Figure 3 Figure 4 PMID:2681799

  3. Positron emission tomography / computerized tomography evaluation of primary Hodgkin's disease of liver.

    PubMed

    Gota, V S; Purandare, N C; Gujral, S; Shah, S; Nair, R; Rangarajan, V

    2009-01-01

    Occurrence of primary Hodgkin's lymphoma (PHL) of the liver is extremely rare. We report on a case of a 60-year-old male who presented with liver mass and B-symptomatology. Hepatoma or hepatic metastasis from a gastrointestinal primary was initially suspected. Tumor markers like AFP, CEA, Total PSA, and CA-19.9 were within normal limits. Positron Emission Tomography / Computerized Tomography (PET/CT) revealed a large hepatic lesion and a nodal mass in the porta hepatis. A liver biopsy was consistent with Hodgkin's lymphoma. There was complete regression of the hepatic lesion and evidence of shrinkage of the nodal mass following four cycles of chemotherapy. 18F Fluro -de-oxy Glucose (FDG) PET / CT in this case helped in establishing a primary hepatic lymphoma by demonstrating the absence of pathologically hypermetabolic foci in any other nodes or organs. PET / CT scan is a useful adjunct to conventional imaging and histopathology, not only to establish the initial diagnosis, but also to monitor treatment response in PHL.

  4. A Comparison of Computerized Job Matching Systems. Second Edition.

    ERIC Educational Resources Information Center

    Botterbusch, Karl F.

    This publication describes and compares 15 nationally available computerized job matching systems. The first section discusses job matching systems in general and provides an outline and a summary comparison table of the systems. The second section, which makes up the major part of the document, contains descriptions of 15 systems. For each…

  5. Infantile Autism and Computerized Tomography Brain-Scan Findings: Specific versus Nonspecific Abnormalities.

    ERIC Educational Resources Information Center

    Balottin, Umberto; And Others

    1989-01-01

    The study of computerized tomography brain-scan findings with 45 autistic and 19 control subjects concluded that autism is nonspecifically associated with brain-scan abnormalities, and that other nonorganic, as well as organic, factors should be taken into account. (Author/DB)

  6. A new cone beam computerized tomography system for use in endodontic surgery.

    PubMed

    Tsurumachi, T; Honda, K

    2007-03-01

    To present a newly developed cone beam computerized tomography system (3DX Micro-CT) and its application in endodontic surgery. Cone beam CT has attracted considerable attention as a new diagnostic imaging technique in dentistry. The assessment of fractured endodontic instruments and the planning of endodontic surgery present challenges that conventional radiography cannot meet successfully. In this report, the value of the 3DX cone beam computerized radiography system is illustrated by the case of a fractured endodontic instrument protruding into the maxillary sinus.

  7. Validation of topographic hybrid single-photon emission computerized tomography with computerized tomography scan in patients with and without nonspecific chronic low back pain. A prospective comparative study.

    PubMed

    Van de Kelft, Erik; Verleye, Gino; Van de Kelft, An-Sofie; Melis, Koen; Van Goethem, Johan

    2017-10-01

    The evidence for the treatment for nonspecific chronic low back pain (ns CLBP) is very weak. Besides the complexity of the pain experience, a good biological marker or tool enabling identification of a pain generator is lacking. Hybrid imaging, combining single-photon emission computerized tomography (SPECT) with computerized tomography (CT) scan, has been proposed as useful in the diagnostic workup of patients with CLBP. To evaluate the sensitivity of SPECT-CT in patients with ns CLBP (Group I) as compared with patients without CLBP (Group II). A prospective comparative study. Two hundred patients were enrolled: 96 in Group I and 104 in Group II. Only the physiological measurement of the incidence of hot spots was performed. The hot spots were rated as follows: 0=normal; 1=slightly colored (no hot spot on whole-body bone scan); and 2=clear hot spot (can be identified on the whole-body bone scan and confirmed on SPECT). To analyze the interobserver agreement when using this scoring system, a second independent reading was performed for 50 randomly chosen records. Two hundred patients divided into two groups were referred to the department of Medical and Molecular Imaging for a topographic SPECT-CT. The first group consisted of patients with ns CLBP, diagnosed by a neurosurgeon. The control group consisted of patients referred for SPECT-CT for non-spinal conditions. Hot spots were assessed for all patients. A second independent reading, blinded for the results of the first reader, was performed on 25 randomly selected patients in each group. This study was investigator initiated, and no funding was received. None of the authors or their proxies have a potential conflict of interest. The odds of finding a normal image in the control group are 2.05 times higher than in Group I. The sensitivity score equals 2.37, meaning that the probability of detecting a hot spot (levels 1 or 2) is more than two times higher in Group I. When focusing on level 2 hot spots only, this

  8. [Quantitative computerized tomography in the study of osteoporosis. Our experience].

    PubMed

    Mecozzi, B; Anselmetti, G C

    1992-01-01

    In the diagnosis of osteoporosis there are, today, several techniques for investigating bone mineral density. In this work the authors evaluate the sensitivity of Computed Tomography in the diagnosis of this metabolic disease, because of the built-in competence of this method in determining the density of the anatomical tissues. In a randomised study the Authors performed Single Energy Quantitative Computed Tomography (SEQCT) in estimating the bone mineral density of lumbar vertebrae in 44 female patients. The data obtained were correlated, using the Student "t" test, to the measurements acquired, in the same group of patients, employing Dual Energy X-ray Absorptiometry (DEXA), 27 patients, and Total Body DEXA, 17 patients. Results revealed a good correlation between SEQCT and DEXA (R = 0.89) and statistical significance (p < 0.001). On the contrary there is not a good correlation (R = 0.58) if SEQCT is compared to Total Body DEXA. According to our experience Quantitative Computed Tomography is useful in diagnosis osteoporosis and it should be performed in all post-menopausal patients. This method, which has a high level of precision, is cheap and easily adaptable to every Computed Tomography. Because of the high X-ray dose rate, only DEXA should be performed in monitoring patients undergoing therapy.

  9. Iodine-131 meta-iodobezylguanidine single photon emission computed tomography/computerized tomography in diagnosis of neuro-endocrine tumors

    PubMed Central

    Harisankar, Chidambaram Natrajan Balasubramanian; Mittal, Bhagwant Rai; Bhattacharya, Anish; Kashyap, Raghava; Bhansali, Anil

    2012-01-01

    Metaiodobenzyl guanidine (MIBG) is a derivative of guanethidine and acts as an analogue of nor-epinephrine and is widely used in the imaging of tumors of neuro-endocrine origin. Iodine-123 MIBG has ideal imaging characteristics but is expensive with limited availability. Iodine-131 MIBG is widely used in India and is cheap. Hybrid single photon emission computed tomography (SPECT)/computerized tomography (CT) allows for anatomico-functional imaging and is being tried in MIBG studies. However, the experience with I-131 MIBG is limited. We present a pictorial assay of I-131 MIBG SPECT/CT findings in various MIBG avid tumors. PMID:23599604

  10. Imaging results of multi-modal ultrasound computerized tomography system designed for breast diagnosis.

    PubMed

    Opieliński, Krzysztof J; Pruchnicki, Piotr; Gudra, Tadeusz; Podgórski, Przemysław; Kurcz, Jacek; Kraśnicki, Tomasz; Sąsiadek, Marek; Majewski, Jarosław

    2015-12-01

    Nowadays, in the era of common computerization, transmission and reflection methods are intensively developed in addition to improving classical ultrasound methods (US) for imaging of tissue structure, in particular ultrasound transmission tomography UTT (analogous to computed tomography CT which uses X-rays) and reflection tomography URT (based on the synthetic aperture method used in radar imaging techniques). This paper presents and analyses the results of ultrasound transmission tomography imaging of the internal structure of the female breast biopsy phantom CIRS Model 052A and the results of the ultrasound reflection tomography imaging of a wire sample. Imaging was performed using a multi-modal ultrasound computerized tomography system developed with the participation of a private investor. The results were compared with the results of imaging obtained using dual energy CT, MR mammography and conventional US method. The obtained results indicate that the developed UTT and URT methods, after the acceleration of the scanning process, thus enabling in vivo examination, may be successfully used for detection and detailed characterization of breast lesions in women. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Calcification of all four parathyroid glands in a hemodialysis patient with secondary hyperparathyroidism revealed by computerized tomography.

    PubMed

    Peces, R; Rodríguez, M; González, F; Ablanedo, P

    2001-09-01

    This report describes the parathyroid scan, computerized tomography and histologic findings in a young female hemodialysis patient with severe secondary hyperparathyroidism. These findings included hyperplasia and calcification of all four parathyroid glands.

  12. Sensitivity of radionuclide brain imaging and computerized transaxial tomography in detecting subdural hematoma

    SciTech Connect

    Razzak, M.A.; Mudarris, F.; Christie, J.H.

    1980-04-01

    In a series of 23 patients with surgically proven subdural hematoma of durations ranging between two days to seven months, the detection rate of Tc-99m-pertechnetate brain imaging was higher than computerized transaxial tomography (CT). With dynamic perfusion scanning, the detection rate was 71.5%. In contrast, CT demonstrated the hematoma in 52% of the cases. Lastly, the result of CT scanning was dependent on the size of the subdural hematoma as evaluated at the time of operation.

  13. Dental implants in bilateral bifid canal and compromised interocclusal space using cone beam computerized tomography

    PubMed Central

    Ahmed, Nizar; Arunachalam, Lalitha Tanjore; Jacob, Caroline Annette; Kumar, Suresh Anand

    2016-01-01

    Knowledge of various anatomic landmarks is pivotal for important success. Bifid canals pose a challenge and can lead to difficulties while performing implant surgery in the mandible. Bifid canals can be diagnosed with panoramic radiography and more accurately with cone beam computerized tomography (CBCT). This case report details the placement of the implant in a patient with bilateral bifid canal and compromised interocclusal space, which was successfully treated using CBCT. PMID:27433073

  14. [Osteosarcoma and chondrosarcoma--radiographic differentiation with computerized tomography].

    PubMed

    Tossato, Patricia dos Santos; Pereira, Amanda Cáceres; Cavalcanti, Marcelo Gusmão Paraiso

    2002-01-01

    The purpose of this paper was to associate and compare the radiographic patterns of osteosarcoma and those of chondrosarcoma by means of computed tomography (CT). Computed tomographs of five cases of osteosarcoma and five cases of chondrosarcoma of the head and neck region were analyzed. The sensitivity of CT was calculated based on the results of histopathological examinations. We concluded that CT can facilitate the establishment of the final diagnosis since it is possible to distinguish the individual characteristics of osteosarcomas and chondrosarcomas in that exam.

  15. Evaluation of Biomaterials Using Micro-Computerized Tomography

    NASA Astrophysics Data System (ADS)

    Torris, A. T. Arun; Columbus, K. C. Soumya; Saaj, U. S.; Nair, Manitha B.; Krishnan, Kalliyana V.

    2008-09-01

    Micro-computed tomography or Micro-CT is a high resolution, non-invasive, x-ray scanning technique that allows precise three-dimensional imaging and quantification of micro-architectural and structural parameters of objects. Tomographic reconstruction is based on a cone-beam convolution-back-projection algorithm. Micro-architectural and structural parameters such as porosity, surface area to volume ratio, interconnectivity, pore size, wall thickness, anisotropy and cross-section area of biomaterials and bio-specimens such as trabecular bone, polymer scaffold, bio-ceramics and dental restorative were evaluated through imaging and computer aided manipulation of the object scan data sets.

  16. Diagnostic accuracy of cerebral angiography and computerized transaxial tomography.

    PubMed Central

    Strasberg, Z.; Molot, M. J.; Kapur, P.; Tuttle, R. J.

    1977-01-01

    Computer tomography (CT) of the brain has become widely accepted as an accurate method of studying a variety of intracranial diseases. In a prospective controlled study one group of radiologists interpreted cerebral angiograms and another interpreted CT studies undertaken in the same patients. The overall rates of diagnostic accuracy were similar (81 and 84% for angiography and CT, respectively), albeit less than reported in the literature, and thus support the contention that CT scanning should be available as the initial neuroradiologic examination whenever possible. Images FIG. 1A FIG. 1B FIG. 2A FIG. 2B FIG. 3 PMID:861866

  17. Evaluation of Biomaterials Using Micro-Computerized Tomography

    SciTech Connect

    Torris, A. T. Arun; Columbus, K. C. Soumya; Saaj, U. S.; Krishnan, Kalliyana V.; Nair, Manitha B.

    2008-09-26

    Micro-computed tomography or Micro-CT is a high resolution, non-invasive, x-ray scanning technique that allows precise three-dimensional imaging and quantification of micro-architectural and structural parameters of objects. Tomographic reconstruction is based on a cone-beam convolution-back-projection algorithm. Micro-architectural and structural parameters such as porosity, surface area to volume ratio, interconnectivity, pore size, wall thickness, anisotropy and cross-section area of biomaterials and bio-specimens such as trabecular bone, polymer scaffold, bio-ceramics and dental restorative were evaluated through imaging and computer aided manipulation of the object scan data sets.

  18. Disseminated metastatic penile squamous cell carcinoma detected by fluorodeoxyglucose PET/computerized tomography

    PubMed Central

    Kaya, Zubeyde Rana; Sager, Sait; Halac, Metin; Sonmezoglu, Kerim

    2012-01-01

    Penile cancer is an uncommon malignancy which of the management depends on the clinical stage and location of the lesion. Positron emission tomography/computerized tomography (PET/CT) is a promising method for detection of distant metastatic lesions and therapeutic strategy planning. Here, we report a case of penile squamous cell carcinoma of 57-year-old male patient, was referred to PET/CT department for investigation of metastases. There were significantly increased fluoro-18 fluorodeoxyglucose activities in supradiaphragmatic and infradiaphragmatic lymphatic stations. PMID:23919076

  19. [Analysis of epidermoid carcinomas using panoramic radiography and computerized tomography].

    PubMed

    Pereira, A C; Cavalcanti, M G; Tossato, P S; Guida, F J; Duaik, M C; Kuroishi, M

    2001-01-01

    The purpose of this work was to compare radiographic findings, such as localization and extension of tumors toward the bone and soft tissues, in panoramic radiography and computed tomography (CT). Four radiologists assessed the radiographic findings of 48 patients with the histopathological diagnosis of squamous cell carcinoma in different sites of the maxillofacial region. Panoramic radiographs and computed tomographs were obtained at the University of Iowa Hospitals and Clinics, at FUNDECTO-USP and at the hospital of the University of São Paulo (USP). We observed a considerable limitation of the panoramic radiography in determining the localization and extension of tumors, since it revealed unclear delimitations. Regarding CT, better results were obtained: it was possible to observe the invasion of the tumor toward adjacent soft tissues, as well as the extension of bone destruction and the depth of the lesion, which were confirmed by surgical findings. We concluded that computed tomography demonstrated to be a sensitive radiographic technique for the detection of the involvement of bone and soft tissues, contributing for a more precise diagnosis, surgical planning and intervention. On the other hand, panoramic radiography was considered less sensitive and less efficient than CT, since it shows only unclear borders of the lesions and is not able to assess the involvement of soft tissues.

  20. Current concepts and advances: computerized tomography in sports medicine.

    PubMed

    Buckwalter, Kenneth A

    2009-03-01

    Computed tomography (CT) is a widely used imaging technique. With the introduction of multidetector row technology, CT has been further refined. Although the focus of this transformation has been body and cardiac imaging, orthopedic imaging has benefited greatly. Specifically, the improvements in CT have made it possible to obtain submillimeter-thick slices that enable the creation of high-resolution multiplanar reformations from a single scan. These images usually are indistinguishable from direct plane acquisitions and provide unparalleled detail. Additionally, the factors responsible for causing CT image artifacts when hardware is present are much better understood and the improvements in CT technique and technology can be exploited to provide better images of patients with orthopedic hardware. The detailed multiplanar visualization of joints facilitates CT arthrography that has undergone a renaissance. CT arthrography is useful in the very large athlete or patient, the claustrophobic, and for those patients who fail a conventional magnetic resonance examination or magnetic resonance arthrogram.

  1. Atelectasis observed by computerized tomography after Caesarean section.

    PubMed

    Meira, M N C; Carvalho, C R R; Galizia, M S; Borges, J B; Kondo, M M; Zugaib, M; Vieira, J E

    2010-06-01

    Atelectasis after either vaginal or Caesarean delivery has not been adequately quantified. This study addresses the hypothesis that atelectasis may be worse in women who undergo Caesarean section when compared with vaginal delivery under regional anaesthesia. Twenty healthy non-smoking women submitted to a chest computed tomography (CT) 2 h after delivery in a University Hospital, who had experienced vaginal delivery (n=10) under combined spinal-epidural analgesia or a Caesarean section (n=10) under spinal anaesthesia, were evaluated. The percentage cross-sectional area of atelectasis in dependent lung regions were measured from the CT images obtained at cross-section of the xiphoid process and the top of the diaphragm. The percentage cross-sectional area of atelectasis was 3.95% in the vaginal delivery group and 14.1% in the Caesarean group (P<0.001, Mann-Whitney rank sum test). These results suggested that pulmonary atelectasis is greater after Caesarean section delivery under spinal anaesthesia than after vaginal delivery with combined spinal-epidural analgesia.

  2. A computerized tomography system for transcranial ultrasound imaging.

    PubMed

    Tang, Sai Chun; Clement, Gregory T

    Hardware for tomographic imaging presents both challenge and opportunity for simplification when compared with traditional pulse-echo imaging systems. Specifically, point diffraction tomography does not require simultaneous powering of elements, in theory allowing just a single transmit channel and a single receive channel to be coupled with a switching or multiplexing network. In our ongoing work on transcranial imaging, we have developed a 512-channel system designed to transmit and/or receive a high voltage signal from/to arbitrary elements of an imaging array. The overall design follows a hierarchy of modules including a software interface, microcontroller, pulse generator, pulse amplifier, high-voltage power converter, switching mother board, switching daughter board, receiver amplifier, analog-to-digital converter, peak detector, memory, and USB communication. Two pulse amplifiers are included, each capable of producing up to 400Vpp via power MOSFETS. Switching is based around mechanical relays that allow passage of 200V, while still achieving switching times of under 2ms, with an operating frequency ranging from below 100kHz to 10MHz. The system is demonstrated through ex vivo human skulls using 1MHz transducers. The overall system design is applicable to planned human studies in transcranial image acquisition, and may have additional tomographic applications for other materials necessitating a high signal output.

  3. The computerized tomography scans and their dosimetric safety.

    PubMed

    Iakovou, Ioannis; Karavida, Niovi; Kotzassarlidou, Maria

    2008-01-01

    In recent years, the volume of diagnostic procedures involving the use of ionizing radiation has rapidly increased. Technological advances in computed tomography (CT) equipment, with the availability of multi-slice acquisition and the introduction of hybrid systems, have made this modality extremely popular among other diagnostic procedures, especially in pediatrics and as a screening procedure for asymptomatic adults. Physicians' major radiation-related concern regarding diagnostic imaging, is possible iatrogenic malignancy. According to major national and international organizations responsible for evaluating radiation risks, there is no low-radiation threshold for inducing cancer. This means that no amount of radiation should be considered absolutely safe. Although, the risk of radiation-induced cancer is much smaller than the risk of cancer from natural sources, it can become a public health concern if large numbers of the population undergo increased numbers of CT screening procedures that may even be of uncertain benefit. In order to reduce the overall radiation dose from CT procedures in the population, it is important to keep radiation dose as low as reasonably achievable, by adjusting scanner parameters separately for each individual. In addition, it is crucial to eliminate the inappropriate referrals for CT tests and choose other diagnostic modalities, such as sonography, magnetic resonance imaging systems, or nuclear medicine procedures. While CT remains an important diagnostic procedure, it is important for health care community to reconsider the indications of a CT scan, especially in children and asymptomatic patients. Physicians who prescribe CT could assess its use on a case-by-case basis. When used prudently and optimally, CT remains a very valuable imaging modalitiy for both children and adults.

  4. A computerized tomography study of the morphological interrelationship between the temporal bones and the craniofacial complex

    PubMed Central

    Costa, Helder Nunes; Slavicek, Rudolf; Sato, Sadao

    2012-01-01

    The hypothesis that the temporal bones are at the center of the dynamics of the craniofacial complex, directly influencing facial morphology, has been put forward long ago. This study examines the role of the spatial positioning of temporal bones (frontal and sagittal inclination) in terms of influencing overall facial morphology. Several 3D linear, angular and orthogonal measurements obtained through computerized analysis of virtual models of 163 modern human skulls reconstructed from cone-beam computed tomography images were analyzed and correlated. Additionally, the sample was divided into two subgroups based on the median value of temporal bone sagittal inclination [anterior rotation group (n = 82); posterior rotation group (n = 81)], and differences between groups evaluated. Correlation coefficients showed that sagittal inclination of the temporal bone was significantly (P < 0.01) related to midline flexion, transversal width and anterior–posterior length of the basicranium, to the anterior–posterior positioning of the mandible and maxilla, and posterior midfacial height. Frontal inclination of the temporal bone was significantly related (P < 0.01) to basicranium anterior–posterior and transversal dimensions, and to posterior midfacial height. In comparison with the posterior rotation group, the anterior rotation group presented a less flexed and anterior–posteriorly longer cranial base, a narrower skull, porion and the articular eminence located more superiorly and posteriorly, a shorter posterior midfacial height, the palatal plane rotated clockwise, a more retrognathic maxilla and mandible, and the upper posterior occlusal plane more inclined and posteriorly located. The results suggest that differences in craniofacial morphology are highly integrated with differences in the positional relationship of the temporal bones. The sagittal inclination of the temporal bone seems to have a greater impact on the 3D morphology of the craniofacial complex than

  5. [Evaluation of computerized tomography-guided stereotactic evacuation of putaminal hematomas by somatosensory evoked potentials].

    PubMed

    Takizawa, T; Sato, S; Sano, A; Murakami, Y; Matsumoto, A; Ohta, K

    1986-04-01

    Computerized tomography (CT) guided stereotactic evacuation of intracerebral hematomas is effective and little invasive treatment at subacute or chronic stage. Somatosensory evoked potentials (SEPs) of 23 patients with putaminal hemorrhage whose stereotactic evacuations were performed from day 4 to day 24 are studied about surgical result and CT findings. As for SEP, N20 which is thought to be generated in the thalamus or in the primary parietal area receiving direct projections from the thalamus is used for comparison with functional recovery. Among 12 patients whose N20s before the evacuation showed normal, 9 had good recovery of their hemiplegia. Motor recovery tended to begin quickly after the evacuation and the evacuation of hematomas were thought to make better result than conservative treatment. CT findings of 9 patients with good recovery revealed that the hematomas didn't invade to the internal capsule or invaded to the posterior part of the posterior limb alone. Among 3 patients whose N20s before the evacuation were not distinct and those after the evacuation were normal, 2 had good recovery of their hemiplegia. As those hematomas were relatively large but located laterally, the internal capsule was seem to be not invaded but only compressed. Among 8 patients whose N20s were not distinct both before and after the evacuation, 7 could not get the recovery of their hemiplegia. CT findings of them revealed that the hematomas were large or invaded toward the internal capsule and thalamus. From this study N20s of SEPs are thought to be useful to the decision of indication and the prediction of the functional prognosis about stereotactic evacuation of putaminal hemorrhage.

  6. Vector entropy imaging theory with application to computerized tomography.

    PubMed

    Wang, Yuanmei; Cheng, Jianping; Heng, Pheng Ann

    2002-07-07

    Medical imaging theory for x-ray CT and PET is based on image reconstruction from projections. In this paper a novel vector entropy imaging theory under the framework of multiple criteria decision making is presented. We also study the most frequently used image reconstruction methods, namely, least square, maximum entropy, and filtered back-projection methods under the framework, of the single performance criterion optimization. Finally, we introduce some of the results obtained by various reconstruction algorithms using computer-generated noisy projection data from the Hoffman phantom and real CT scanner data. Comparison of the reconstructed images indicates that the vector entropy method gives the best in error (difference between the original phantom data and reconstruction), smoothness (suppression of noise), grey value resolution and is free of ghost images.

  7. Vector entropy imaging theory with application to computerized tomography

    NASA Astrophysics Data System (ADS)

    Wang, Yuanmei; Cheng, Jianping; Heng, Pheng Ann

    2002-07-01

    Medical imaging theory for x-ray CT and PET is based on image reconstruction from projections. In this paper a novel vector entropy imaging theory under the framework of multiple criteria decision making is presented. We also study the most frequently used image reconstruction methods, namely, least square, maximum entropy, and filtered back-projection methods under the framework of the single performance criterion optimization. Finally, we introduce some of the results obtained by various reconstruction algorithms using computer-generated noisy projection data from the Hoffman phantom and real CT scanner data. Comparison of the reconstructed images indicates that the vector entropy method gives the best in error (difference between the original phantom data and reconstruction), smoothness (suppression of noise), grey value resolution and is free of ghost images.

  8. Positron emission tomography/computerized tomography in the evaluation of primary non-Hodgkin's lymphoma of prostate.

    PubMed

    Pan, Bo; Han, Jian-Kui; Wang, Shi-Cun; Xu, Ao

    2013-10-21

    Primary malignant lymphoma of the prostate is exceedingly rare. Here we report a case of a 65-year-old man who presented with increased urinary frequency, urinary urgency, and urinary incontinence for two years. Benign prostatic hypertrophy was suspected at primary impression. Ultrasound revealed a hypoechoic lesion of the prostate. The total serum prostate-specific antigen was within normal range. Positron emission tomography/computerized tomography (PET/CT) showed a hypermetabolic prostatic lesion. Prostate biopsy was consistent with a non-germinal center diffuse large B cell lymphoma. There was complete remission of the prostatic lesion following six cycles of chemotherapy as shown on the second PET/CT imaging. ¹⁸F-fluoro-deoxy glucose PET/CT is not only a complement to conventional imaging, but also plays a significant role in the diagnosis and evaluation of treatment response of prostatic lymphoma.

  9. Intracranial Leptomeningeal Carcinomatosis in Three Cases from Breast Cancer Demonstrated on F-18 Fluorodeoxyglucose Positron Emission Tomography/Computerized Tomography.

    PubMed

    Ortapamuk, Hulya; Demir, Mustafa Kemal

    2017-01-01

    Leptomeningeal carcinomatosis (LC) is an uncommon late manifestation of non-central nervous system (CNS) solid tumors. With prolonged survival in solid tumors, an increased frequency of metastases is noted in these tumors too. The detection of tumor cells in the cerebrospinal fluid remains the gold standard. Noninvasively, magnetic resonance imaging is frequently used for the diagnosis of LC. Although its low sensitivity of F-18 fluorodeoxyglucose positron emission tomography/computerized tomography (F-18 FDG PET/CT) on demonstrating CNS lesions, it could be useful in identifying the possibility of LC of breast carcinoma by giving high attention to the meninges. We discuss here three cases all of them having intracranial LC; where (18)F-FDG PET/CT study helped us in the diagnosis of LC. To our knowledge, this is the second report about intracranial LC from breast cancer demonstrating on (18)F-FDG PET/CT.

  10. Intracranial Leptomeningeal Carcinomatosis in Three Cases from Breast Cancer Demonstrated on F-18 Fluorodeoxyglucose Positron Emission Tomography/Computerized Tomography

    PubMed Central

    Ortapamuk, Hulya; Demir, Mustafa Kemal

    2017-01-01

    Leptomeningeal carcinomatosis (LC) is an uncommon late manifestation of non-central nervous system (CNS) solid tumors. With prolonged survival in solid tumors, an increased frequency of metastases is noted in these tumors too. The detection of tumor cells in the cerebrospinal fluid remains the gold standard. Noninvasively, magnetic resonance imaging is frequently used for the diagnosis of LC. Although its low sensitivity of F-18 fluorodeoxyglucose positron emission tomography/computerized tomography (F-18 FDG PET/CT) on demonstrating CNS lesions, it could be useful in identifying the possibility of LC of breast carcinoma by giving high attention to the meninges. We discuss here three cases all of them having intracranial LC; where 18F-FDG PET/CT study helped us in the diagnosis of LC. To our knowledge, this is the second report about intracranial LC from breast cancer demonstrating on 18F-FDG PET/CT. PMID:28242978

  11. Detection of drugs and explosives using neutron computerized tomography and artificial intelligence techniques.

    PubMed

    Ferreira, F J O; Crispim, V R; Silva, A X

    2010-06-01

    In this study the development of a methodology to detect illicit drugs and plastic explosives is described with the objective of being applied in the realm of public security. For this end, non-destructive assay with neutrons was used and the technique applied was the real time neutron radiography together with computerized tomography. The system is endowed with automatic responses based upon the application of an artificial intelligence technique. In previous tests using real samples, the system proved capable of identifying 97% of the inspected materials. Copyright 2010 Elsevier Ltd. All rights reserved.

  12. Numerical calculation of the rock permittivity using micro computerized tomography image

    NASA Astrophysics Data System (ADS)

    Guo, Chen; Liu, Richard; Jin, Zhao; He, Zhili

    2014-05-01

    A numerical evaluation of the permittivity of sandstones through the micro computerized tomography (micro CT) images at 1.1 GHz is conducted by using an image porosity extracting algorithm and an improved Finite Difference Method (FDM). Within the acquired physical properties by 3D micro CT scanning, numerical method is used to compute the permittivity of the rock samples. A resonant cavity is used for experimental measurement. The simulated results of 2 clastic sandstone samples with dry state and saturated state are compared with experimental data for validating the accuracy of the proposed numerical method. The results show great agreement and the error of permittivity evaluation is less than 3%.

  13. Asymptomatic Emphysematous Pyelonephritis - Positron Emission Tomography Computerized Tomography Aided Diagnostic and Therapeutic Elucidation

    PubMed Central

    Pathapati, Deepti; Shinkar, Pawan Gulabrao; kumar, Satya Awadhesh; Jha; Dattatreya, Palanki Satya; Chigurupati, Namrata; Chigurupati, Mohana Vamsy; Rao, Vatturi Venkata Satya Prabhakar

    2017-01-01

    The authors report an interesting coincidental unearthing by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) of a potentially serious medical condition of emphysematous pyelonephritis in a case of nasopharyngeal carcinoma. The management by conservative ureteric stenting and antibiotics was done with gratifying clinical outcome. PMID:28242985

  14. Non-Conventional Applications of Computerized Tomography: Analysis of Solid Dosage Forms Produced by Pharmaceutical Industry

    SciTech Connect

    Martins de Oliveira, Jose Jr.; Germano Martins, Antonio Cesar

    2010-05-21

    X-ray computed tomography (CT) refers to the cross-sectional imaging of an object measuring the transmitted radiation at different directions. In this work, we describe a non-conventional application of computerized tomography: visualization and improvements in the understanding of some internal structural features of solid dosage forms. A micro-CT X-ray scanner, with a minimum resolution of 30 mum was used to characterize some pharmaceutical tablets, granules, controlled-release osmotic tablet and liquid-filled soft-gelatin capsules. The analysis presented in this work are essentially qualitative, but quantitative parameters, such as porosity, density distribution, tablets dimensions, etc. could also be obtained using the related CT techniques.

  15. Non-Conventional Applications of Computerized Tomography: Analysis of Solid Dosage Forms Produced by Pharmaceutical Industry

    NASA Astrophysics Data System (ADS)

    de Oliveira, José Martins; Germano Martins, Antonio César

    2010-05-01

    X-ray computed tomography (CT) refers to the cross-sectional imaging of an object measuring the transmitted radiation at different directions. In this work, we describe a non-conventional application of computerized tomography: visualization and improvements in the understanding of some internal structural features of solid dosage forms. A micro-CT X-ray scanner, with a minimum resolution of 30 μm was used to characterize some pharmaceutical tablets, granules, controlled-release osmotic tablet and liquid-filled soft-gelatin capsules. The analysis presented in this work are essentially qualitative, but quantitative parameters, such as porosity, density distribution, tablets dimensions, etc. could also be obtained using the related CT techniques.

  16. Computerized Tomography-Guided Paracentesis: An Effective Alternative to Bedside Paracentesis?

    PubMed Central

    Gaduputi, Vinaya; Tariq, Hassan; Chandrala, Chaitanya; Sakam, Sailaja; Abbas, Naeem; Chilimuri, Sridhar

    2017-01-01

    Background Ascites remains the most common cause of hospitalization among patients with decompensated cirrhosis. Paracentesis is a relatively safe procedure with low complication rates. Computerized tomography (CT)-guided therapeutic paracentesis could be a safe and effective alternative to unaided or aided (ultrasonogram-guided) bedside paracentesis. In this retrospective study, we aimed to compare the efficacy, safety, and cost-effectiveness of CT-guided paracentesis with bedside paracentesis. Methods The period of study was from 2002 to 2012. All patients with cirrhosis who underwent therapeutic paracentesis were included in the study. These patients were divided into two groups. Group I consisted of patients who underwent CT-guided pigtail catheter insertion with ascitic fluid drainage. Group II consisted of patients who underwent beside therapeutic paracentesis after localization of fluid either by physical examination or sonographic localization. We measured the efficacy of CT-guided paracentesis and bedside paracentesis in terms of volume of fluid removed, length of stay, discharge doses of diuretics (spironolactone and furosemide) and number of days to readmission for symptomatic ascites. We also computed the cost-effectiveness of CT-guided therapeutic paracentesis when compared to a bedside procedure. Fischer exact test was used to analyze the distribution of categorical data and unpaired t-test was used for comparison of means. Results There were a total of 546 unique patients with diagnosed cirrhosis who were admitted to the hospital with symptomatic ascites and underwent therapeutic paracentesis. Two hundred and forty-seven patients underwent CT-guided paracentesis, while 272 patients underwent bedside paracentesis. There was significant inverse correlation between the amount of ascitic fluid removed and total length of stay in the hospital. We found that the volume of fluid removed via a CT-guided pigtail insertion and drainage (2.72 ± 2.02 L) is

  17. Central representation of phantom limb phenomenon in amputees studied with single photon emission computerized tomography.

    PubMed

    Liaw, M Y; You, D L; Cheng, P T; Kao, P F; Wong, A M

    1998-01-01

    To explore the possible mechanisms of phantom limb discomfort after amputation, three amputees with phantom limb pain were studied. This study examined the change of regional cerebral blood flow using technetium-99m hexamethylpropyleneamine oxime-single photon emission computerized tomography, which was arranged at the time of severe phantom limb discomfort and after the discomfort subsided or was completely relieved. Nine representative transverse slices parallel to the orbitomeatal line were selected for quantification. The cortical ribbon (2-cm thickness) was equally subdivided into 12 symmetrical pairs of sector regions of interest in each slice. The irregularly shaped regions of interest were drawn manually around the right thalamus and basal ganglion and then mirrored to the left thalamus and basal ganglion. The contralateral to ipsilateral ratio of regional cerebral blood flow for each area was calculated. The intensity of phantom limb pain was evaluated on a 0 to 10 visual analog scale. In Cases 1 and 2, the contralateral to ipsilateral regional cerebral blood flow ratios of multiple areas of the frontal, temporal, or parietal lobes were increased at the time of more severe phantom limb pain, and the ratios were normalized or even decreased when the phantom limb pain subsided. In Case 3, increased contralateral to ipsilateral regional cerebral blood flow ratios were also found over the frontal, temporal, and parietal lobe. However, most of the increased regional cerebral blood flow ratios of regions of interest in the first study persisted in the follow-up study. Also, the regional cerebral blood flow ratios of greater number of regions of interest of the same gyrus and new gyrus were increased. There was no significant right-left difference of regional cerebral blood flow over bilateral thalami and basal ganglia in all three cases. The results suggested that phantom limb pain might be associated with cortical activation involving the frontal, temporal, or

  18. The role of renal scintigraphy and unenhanced helical computerized tomography in patients with ureterolithiasis.

    PubMed

    Lorberboym, M; Kapustin, Z; Elias, S; Nikolov, G; Katz, R

    2000-04-01

    Unenhanced helical computerized tomography (UHCT) has recently evolved as an accurate imaging modality for determination of the presence or absence of ureterolithiasis in patients with acute flank pain. Functional renal scintigraphy is considered the gold standard for urinary tract obstruction. The objective of this study was to correlate the secondary signs of urinary obstruction on UHCT with findings of functional renal scintigraphy. UHCT was performed in 30 patients admitted to the emergency room with acute flank pain. All patients had a calcified urinary stone identified on UHCT. The location of each urinary stone was classified as ureteral or in the ureterovesical junction. The presence of secondary CT signs of ureteral obstruction was determined for each patient. After oral or intravenous hydration, a technetium-99m diethylene triamine penta-acetic acid renal scan was performed in all patients within 12 h of the CT scan. Follow-up delayed scintigraphic images were obtained at 2 h and 24 h in patients with evidence of ureteral obstruction. The sensitivity, specificity and predictive values of each possible combination of CT findings were determined by comparison with the scintigraphic results. The distal ureter was the most common location for a calculus on UHCT, followed in frequency by the ureterovesical junction, proximal ureter and mid-ureter. The renograms showed high-grade, unilateral obstruction in 12 patients, indeterminate scans in five patients and normal renograms in 13 patients. The sensitivities and specificities of individual CT findings ranged from 50% to 75% and from 8% to 69%, respectively. Perinephric stranding gave the highest positive predictive value (PPV) for obstruction (69% including indeterminate renograms). None of the individual CT findings showed a statistically significant correlation with scintigraphic findings. A combination of one or two positive CT findings had a PPV of only 25% for obstruction. A combination of three or four

  19. [Computerized axial tomography of the skull - diagnostic possibilities and clinical results (author's transl)].

    PubMed

    Kazner, E; Lanksch, W; Steinhoff, H; Wilske, J

    1975-10-01

    Computerized axial tomography is a new method of tissue examination with x-rays whereby a picture can be produced which is a representation of a slice of the skull. This is done by irradiating the skull from 180 or 225 incremental angles and measuring the absorption at each of these angles. Then with the aid of a computer a tomogram is produced which can be displayed on a screen. These tomograms are representations of a cross-section of the skull composed of 160 X 160 points showing the various intracranial structures with great detail. The present study demonstrates the diagnostic possibilities of the high definition matrix with reference to brain disorders in a large sample of patients for the first time. Some tumours are shown as areas of decreased absorption compared with normal brain tissue. Others, however, have been found to have higher absorption values. With glioblastomas very contrasting pictures are produced with coexistng areas of decreased, increased and similar values to brain tissue. The most important finding is the visualization of brain oedema which appears as a low density area. A grading system of brain oedemas is proposed. The brain oedema associated with tumours has been found to propagate mainly in the white matter producing finger-like shapes. Out of 209 intracranial tumours 203 were recognized in the plain scan, a further five after contrast enhancement. In patients who have suffered from a stroke the differentiation between haemorrhage and infarction is made simple due to the contrasting appearance between the two types of lesion. Location, size and propagation direction of a haematoma as well as rupture of a haemorrhage into the ventricular system can be defined exactly. With brain infarction the hypoxically damaged tissue is well delineated and readily attributable to a given vascular area. In head injuries, for the first time it is possible to differentiate brain contusion with oedema from intracerebral haematoma. Coup and contre

  20. Computerized axial tomography of the chest for visualization of ''absent'' pulmonary arteries

    SciTech Connect

    Sondheimer, H.M.; Oliphant, M.; Schneider, B.; Kavey, R.E.W.; Blackman, M.S.; Parker, F.B. Jr.

    1982-05-01

    To expand the search for central pulmonary arteries in six patients with absence of cardiac-pulmonary continuity, computerized axial tomography (CAT) of the chest was performed. The CAT scans were compared with previous arteriograms and pulmonary vein wedge angiograms. Three patients with type IV truncus arteriosus were studied, and none had a central, right or left pulmonary artery on CAT scan. However, two patients with tetralogy of Fallot with pulmonary atresia and a patent ductus arteriosus to the right lung demonstrated the presence of a left pulmonary artery. In addition, one child with truncus arteriosus with ''absent'' left pulmonary artery demonstrated a left pulmonary artery on the CAT scan. The CAT scan may therefore enhance our ability to search for disconnected pulmonary arteries in children with complex cyanotic congenital heart disease.

  1. Single photon emission computerized tomography (SPECT) in detecting neurodegeneration in Huntington's disease.

    PubMed

    Reynolds, N C; Hellman, R S; Tikofsky, R S; Prost, R W; Mark, L P; Elejalde, B R; Lebel, R; Hamsher, K S; Swanson, S; Benezra, E E

    2002-01-01

    Single photon emission computerized tomography (SPECT) studies were performed on 34 manifest Huntington's disease (HD) patients at various stages of clinical pathology ranging from early chorea to late dystonia with or without signs of dementia and 12 pre-symptomatic patients with abnormal terminal CAG expansions. Thirty HD patients with obvious clinical signs and seven pre-symptomatic patients without signs or symptoms of HD displayed selective caudate hypoperfusion by direct visual inspection. Such qualitative, selective striatal hypoperfusion patterns can be indicative of early and persistent metabolic changes in striatal neuropathology. SPECT studies can be useful in documenting early pre-clinical changes in patients with abnormal terminal CAG expansions and in confirming the presence of caudate pathology in patients with clinical signs of HD.

  2. Square wave cone beam scanning trajectory for data completeness in three-dimensional computerized tomography

    SciTech Connect

    Eberhard, J.W.; Hedengren, K.H.V.

    1991-12-17

    This paper describes a scanning and data acquisition method for three-dimensional computerized tomography (CT) imaging of a field of view containing at least a portion of an object illuminated by a cone beam source. It comprises: defining a source scanning trajectory as a path traversed by the source; employing the cone beam source fixed with reference to a two-dimensional array detector with both source and detector movably positioned relative to the object in order to scan about the object; specifying the source scanning trajectory as a square wave on a cylindrical surface surrounding the field of view such that each plane passing through the field of view intersects the scanning trajectory in at lease one point; and scanning at a plurality of positions along the source scanning trajectory to obtain cone beam projection data.

  3. Definition of hepatic tumor microcirculation by Single Photon Emission Computerized Tomography (SPECT)

    SciTech Connect

    Gyves, J.W.; Ziessman, H.A.; Ensminger, W.D.; Thrall, J.H.; Niederhuber, J.E.; Keyes, J.W. Jr.; Walker, S.

    1984-09-01

    Single photon emission computerized tomography coupled with Tc-99m MAA hepatic-arterial perfusion scintigraphy has been used to examine the density of the functional microcirculation of hepatic tumors relative to normal liver in 24 patients. In both colorectal and carcinoid tumors the authors have demonstrated an average three-fold greater arteriolar-capillary density in areas of tumor proliferation. The depth of the evoked tumor hypervascularity was found to extend about 4 cm. Tumors greater than 8-9 cm in diameter were uniformly found to have a central hypovascular core. These observations are of importance in the design of selective strategies utilizing therapeutic microspheres directed against the hypervascular proliferating regions of human tumors.

  4. The influence of species composition on flow field's optical computerized tomography diagnosis

    NASA Astrophysics Data System (ADS)

    Yun-yun, Chen; Fang, Gu; Ling-bing, Bu; Ying-ying, Zhang

    2017-07-01

    The species composition is one of the factors which could affect the refractive index of flow fields. So, the determination of species composition should be a key point, when optical computerized tomography (OCT) methods are applied to measure the key parameters of flow fields. In this paper, the influence of species composition on flow field's temperature diagnosis will be discussed both in theory and experiment. The final results manifest that the determination of species composition could affect not only the specific temperature values, but also the structure and distribution of the temperature. Meanwhile, it is also found that the nonlinear regular of the maximal temperature variation with the distance between the cross section and nozzle is the same in different models. Finally, the condition, which could be applied to judge whether the effect of species composition can be omitted, is proposed.

  5. Feasibility of optical computerized tomography for measuring the species concentration distribution of flow fields

    NASA Astrophysics Data System (ADS)

    Chen, Yun-yun; Yu, Yang; Chen, Xuan; Zhang, Ying-ying

    2017-08-01

    In this paper, the feasibility of using optical computerized tomography (OCT) methods for measuring the distribution of species concentration for flow fields is analyzed and discussed. First, feasible methods are chosen for two or three objects composed flow fields from the perspective of the measurable principle. Second, both common gas and plasma are chosen as two typical examples for specific analysis and discussion. The results show that the feasibility and applicable range of OCT methods are related to the temperature, pressure, and species composition of the measured flow fields. Finally, the study indicates that OCT methods are more suitable for measuring the distribution of species composition for common gas rather than plasma. In a word, this study could be helpful for extending the applicable range of OCT methods, which are based on the measurement of the refractive index.

  6. Oral chloral hydrate vs. intranasal midazolam for sedation during computerized tomography.

    PubMed

    Fallah, Razieh; Nakhaei, Mohammad Hosein Ataee; Behdad, Shekofah; Moghaddam, Reza Nafisi; Shamszadeh, Ali

    2013-02-01

    We conducted this single blind randomized clinical trial to compare the efficacy and safety of oral chloral hydrate and intranasal midazolam for induction of sedation for computerized tomography scan of brain in children. Participants aged 1-10 years (n=60) were randomized to receive 100 mg/kg chloral hydrate orally with intra nasal normal saline OR intranasal midazolam 0.2 mg/kg with oral normal saline. Adequate sedation (Ramsay sedation score of four) was obtained and CT scan completed successfully in 76.7% of chloral hydrate group and in 40% of midazolam group (P=0.004). No significant difference was seen for side effects frequency between the two drugs (10% in chloral hydrate, 3.3% in midazolam group; P=0.34). We conclude that oral chloral hydrate can be considered as a safe and effective drug for sedation in children undergoing CT scan of brain.

  7. The mobile hospital technology industry: focus on the computerized tomography scanner.

    PubMed

    Hartley, D; Moscovice, I

    1996-01-01

    This study of firms offering mobile hospital technology to rural hospitals in eight northwestern states found that several permanently parked computerized tomography (CT) units were found where mobile routes had atrophied due to the purchase of fixed units by former mobile CT hospital clients. Based on a criterion of 140 scans per month per unit as a threshold of profitable production, units owned by larger firms (those that operate five or more units) were more likely to be profitable than units owned by smaller firms (71% versus 20%, P = 0.03). A substantial number of rural hospitals lose money on mobile CT due to low Medicare reimbursement. In some areas, mobile hospital technology is a highly competitive industry. Evidence was found that several firms compete in some geographic areas and that some firms have lost hospital clients to competing vendors.

  8. Computerized tomography of pelvic osteomyelitis in patients with spinal cord injuries

    SciTech Connect

    Firooznia, H.; Rafii, M.; Golimbu, C.; Sokolow, J.

    1983-12-01

    Computerized tomography (CT) was performed in 19 patients with spinal cord injury (SCI) who had large pressure sores and in whom other complications were suspected. CT detected the depth, extent, and degree of undermining of the edges of the pressure sores in 19 of 27 lesions. Conventional radiography detected four cases of pelvic osteomyelitis. CT detected eight additional cases of pelvic osteomyelitis, as well as eight clinically unsuspected peripelvic and intrapelvic abscesses. Technetium-99m bone scanning was not very helpful because of localization in chronic proliferative changes of bone and widespread foci of myositis ossificans, as well as in osteomyelitis. Gallium-67 scanning detected only one of six abscesses. It was not very helpful because of confusion of abscess and osteomyelitis with intense soft tissue swelling and cellulitis, which are often associated with pressure sores in patients with chronic SCI. CT was found to be, by far, the modality of choice for detection of pelvic osteomyelitis and abscess in patients with SCI.

  9. Prevention of atelectasis in morbidly obese patients during general anesthesia and paralysis: a computerized tomography study.

    PubMed

    Reinius, Henrik; Jonsson, Lennart; Gustafsson, Sven; Sundbom, Magnus; Duvernoy, Olov; Pelosi, Paolo; Hedenstierna, Göran; Fredén, Filip

    2009-11-01

    Morbidly obese patients show impaired pulmonary function during anesthesia and paralysis, partly due to formation of atelectasis. This study analyzed the effect of general anesthesia and three different ventilatory strategies to reduce the amount of atelectasis and improve respiratory function. Thirty patients (body mass index 45 +/- 4 kg/m) scheduled for gastric bypass surgery were prospectively randomized into three groups: (1) positive end-expiratory pressure of 10 cm H2O (PEEP), (2) a recruitment maneuver with 55 cm H2O for 10 s followed by zero end-expiratory pressure, (3) a recruitment maneuver followed by PEEP. Transverse lung computerized tomography scans and blood gas analysis were recorded: awake, 5 min after induction of anesthesia and paralysis at zero end-expiratory pressure, and 5 min and 20 min after intervention. In addition, spiral computerized tomography scans were performed at two occasions in 23 of the patients. After induction of anesthesia, atelectasis increased from 1 +/- 0.5% to 11 +/- 6% of total lung volume (P < 0.0001). End-expiratory lung volume decreased from 1,387 +/- 581 ml to 697 +/- 157 ml (P = 0.0014). A recruitment maneuver + PEEP reduced atelectasis to 3 +/- 4% (P = 0.0002), increased end-expiratory lung volume and increased Pao2/Fio2 from 266 +/- 70 mmHg to 412 +/- 99 mmHg (P < 0.0001). PEEP alone did not reduce the amount of atelectasis or improve oxygenation. A recruitment maneuver + zero end-expiratory pressure had a transient positive effect on respiratory function. All values are presented as mean +/- SD. A recruitment maneuver followed by PEEP reduced atelectasis and improved oxygenation in morbidly obese patients, whereas PEEP or a recruitment maneuver alone did not.

  10. Compact cold stage for micro-computerized tomography imaging of chilled or frozen samples

    NASA Astrophysics Data System (ADS)

    Hullar, Ted; Paige, David F.; Rowland, Douglas J.; Anastasio, Cort

    2014-04-01

    High resolution X-ray microCT (computerized tomography) can be used to image a variety of objects, including temperature-sensitive materials. In cases where the sample must be chilled or frozen to maintain sample integrity, either the microCT machine itself must be placed in a refrigerated chamber, or a relatively expensive commercial cold stage must be purchased. We describe here the design and construction of a low-cost custom cold stage suitable for use in a microCT imaging system. Our device uses a boron nitride sample holder, two-stage Peltier cooler, fan-cooled heat sink, and electronic controller to maintain sample temperatures as low as -25 °C ± 0.2 °C for the duration of a tomography acquisition. The design does not require modification to the microCT machine, and is easily installed and removed. Our custom cold stage represents a cost-effective solution for refrigerating CT samples for imaging, and is especially useful for shared equipment or machines unsuitable for cold room use.

  11. Weight-based contrast administration in the computerized tomography evaluation of acute pulmonary embolism

    PubMed Central

    Laurent, Lisa; Zamfirova, Ina; Sulo, Suela; Baral, Pesach

    2017-01-01

    Abstract Compare individualized contrast protocol, or weight-based protocol, to standard methodology in evaluating acute pulmonary embolism. Retrospective chart review was performed on patients undergoing computed tomography angiography with standard contrast protocol (n = 50) or individualized protocol (n = 50). Computerized tomography images were assessed for vascular enhancement and image quality. Demographics were comparable, however, more patients in the individualized group were admitted to intensive care unit (48% vs 16%, P = 0.004). Vascular enhancement and image quality were also comparable, although individualized protocol had significantly fewer contrast and motion artifact limitations (28% vs 48%, P = 0.039). Fifteen percent decrease in intravenous contrast volume was identified in individualized group with no compromise in image quality. Individualized contrast protocol provided comparable vascular enhancement and image quality to the standard, yet with fewer limitations and lower intravenous contrast volume. Catheter-gauge flow rate restrictions resulting in inconsistent technologist exam execution were identified, supporting the need for further investigation of this regimen. PMID:28151887

  12. Compact cold stage for micro-computerized tomography imaging of chilled or frozen samples

    SciTech Connect

    Hullar, Ted; Anastasio, Cort; Paige, David F.; Rowland, Douglas J.

    2014-04-15

    High resolution X-ray microCT (computerized tomography) can be used to image a variety of objects, including temperature-sensitive materials. In cases where the sample must be chilled or frozen to maintain sample integrity, either the microCT machine itself must be placed in a refrigerated chamber, or a relatively expensive commercial cold stage must be purchased. We describe here the design and construction of a low-cost custom cold stage suitable for use in a microCT imaging system. Our device uses a boron nitride sample holder, two-stage Peltier cooler, fan-cooled heat sink, and electronic controller to maintain sample temperatures as low as −25 °C ± 0.2 °C for the duration of a tomography acquisition. The design does not require modification to the microCT machine, and is easily installed and removed. Our custom cold stage represents a cost-effective solution for refrigerating CT samples for imaging, and is especially useful for shared equipment or machines unsuitable for cold room use.

  13. Application of proton magnetic resonance spectroscopy and computerized tomography in the diagnosis and treatment of nonalcoholic fatty liver disease.

    PubMed

    Wang, Nan; Dong, Hui; Wei, Shichao; Lu, Fuer

    2008-06-01

    In order to investigate the application of proton magnetic resonance spectroscopy ((1)H-MRS) and computerized tomography (CT) in the quantitative diagnosis of nonalcoholic fatty liver disease (NAFLD) and evaluation of therapeutic effects, 22 patients with NAFLD were selected according to the Chinese Medical Association's (CMA) standard of the NAFLD in comparison with 20 healthy volunteers (as control group). Blood samples for biochemistry were collected. The severity of hepatosteatosis was evaluated by (1)H-MRS scan and CT scan of liver. The intrahepatic content of lipid (IHCL) and CT value ratio of liver to spleen were calculated. The patients in NAFLD group were treated with Ganzhixiao Capsule for 8 weeks. The changes in IHCL and CT value ratio of liver to spleen were observed before and after treatment. In NAFLD group serum ALT, TG, IHCL calculated by (1)HMRS were increased and CT value ratio of liver to spleen decreased significantly as compared with control group. After treatment for 8 weeks serum ALT, TG, IHCL were decreased significantly, while CT value ratio of liver to spleen increased significantly in NAFLD group. It was suggested that IHCL could be measured precisely by (1)HMRS. NAFLD was treated effectively by Ganzhixiao capsule.

  14. Computerized tomography technique for reconstruction of obstructed temperature field in infrared thermography

    NASA Astrophysics Data System (ADS)

    Sham, F. C.; Huang, Y. H.; Liu, L.; Chen, Y. S.; Hung, Y. Y.; Lo, T. Y.

    2010-01-01

    Infrared thermography is a rapid, non-invasive and full-field technique for non-destructive testing and evaluation (NDT&E). With all the achievements on IR instrumentation and image processing techniques attained, it has been extended far beyond simple hot-spot detection and becomes one of the most promising NDT&E techniques in the last decades. It has achieved increasing acceptance in different sectors include medical imaging, manufacturing component fault detection and buildings diagnostic. However, one limitation of IR thermography is that the testing results are greatly affected by object surface emissivity. Surface with various emissivities may lead to difficult discrimination between area of defect and area with different emissivity. Therefore, many studies have been carried out on eliminating emissivity, for example, the time derivative approach, lock-in processing and differential contrast measurements. In these methods, sequence of themo-data/images are recorded and being processed in order to eliminate differences of emissivity. Another problem of IR thermography is that any obstruction may limit stimulations and imaging which leads to the observation of unclear defect image. To solve this problem, this paper proposes an algorithm based on the principle of computerized tomography which permits the reconstruction of unavailable/partially available temperature distribution of the affected area using the measured surrounding temperature field. In the process, a set of imaginary rays are projected from many different directions across the area. For each ray, integration of the temperature derivatives along the ray is equals to the temperature difference between the boundary points intercepted by the ray. Therefore, a set of linear equations can be established by considering the multiple rays. Each equation expresses the unknown temperature derivatives in the affected area in terms of the measured boundary temperature data. Solution of the set of simultaneous

  15. Cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial region: a systematic review of the literature.

    PubMed

    De Vos, W; Casselman, J; Swennen, G R J

    2009-06-01

    This study reviewed the literature on cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial (OMF) region. A PUBMED search (National Library of Medicine, NCBI; revised 1 December 2007) from 1998 to December 2007 was conducted. This search revealed 375 papers, which were screened in detail. 176 papers were clinically relevant and were analyzed in detail. CBCT is used in OMF surgery and orthodontics for numerous clinical applications, particularly for its low cost, easy accessibility and low radiation compared with multi-slice computerized tomography. The results of this systematic review show that there is a lack of evidence-based data on the radiation dose for CBCT imaging. Terminology and technical device properties and settings were not consistent in the literature. An attempt was made to provide a minimal set of CBCT device-related parameters for dedicated OMF scanners as a guideline for future studies.

  16. Kidney Stone Volume Estimation from Computerized Tomography Images Using a Model Based Method of Correcting for the Point Spread Function

    PubMed Central

    Duan, Xinhui; Wang, Jia; Qu, Mingliang; Leng, Shuai; Liu, Yu; Krambeck, Amy; McCollough, Cynthia

    2014-01-01

    Purpose We propose a method to improve the accuracy of volume estimation of kidney stones from computerized tomography images. Materials and Methods The proposed method consisted of 2 steps. A threshold equal to the average of the computerized tomography number of the object and the background was first applied to determine full width at half maximum volume. Correction factors were then applied, which were precalculated based on a model of a sphere and a 3-dimensional Gaussian point spread function. The point spread function was measured in a computerized tomography scanner to represent the response of the scanner to a point-like object. Method accuracy was validated using 6 small cylindrical phantoms with 2 volumes of 21.87 and 99.9 mm3, and 3 attenuations, respectively, and 76 kidney stones with a volume range of 6.3 to 317.4 mm3. Volumes estimated by the proposed method were compared with full width at half maximum volumes. Results The proposed method was significantly more accurate than full width at half maximum volume (p <0.0001). The magnitude of improvement depended on stone volume with smaller stones benefiting more from the method. For kidney stones 10 to 20 mm3 in volume the average improvement in accuracy was the greatest at 19.6%. Conclusions The proposed method achieved significantly improved accuracy compared with threshold methods. This may lead to more accurate stone management. PMID:22819107

  17. [Evaluation of the availability, utilization, and costs of computerized tomography in the state of Morelos, Mexico].

    PubMed

    Pérez-Rodríguez, John; Durán-Arenas, Juan Luis Gerardo; Hernández-Gaytán, Sendy Isarel; Tirado-Gómez, Laura Leticia; Díaz-Vásquez, Francisco Javier; López-Cervantes, Malaquías

    2002-01-01

    To assess the availability, utilization, and costs of computerized tomography (CT scan) in private and public hospitals in Morelos State, Mexico. From January to April 1999, a cross-sectional study was carried out in two private and two public hospitals in Morelos, Mexico. Individual face-to-face interviews were conducted with directors, managers, radiologists, and heads of maintenance at each hospital. Statistical analysis was performed to describe the variables measuring availability, utilization, and costs of CT scans. A comprehensive assessment of CT scans was also performed. Emphasis was made on the variability of observed patterns among the participating hospitals. CT scan technology has been used by hospitals in Morelos State for over ten years; programs for preventive or corrective maintenance of these equipments are available, although at high costs. No strategies for technology assessment are available for acquisition of CT scanners nor during their period of utilization. This study did not attempt to evaluate the appropriateness of the clinical use of CT nor its untoward effects. Findings from the present study showed that: 1) a lack of mechanisms for technology assessment and management of CT scans prevented hospitals from managing CT scanning technologies efficiently; 2) technology assessment regulation is not available, even though it is necessary for the adequate selection of the best technologies, on the basis of their efficiency, effectiveness, safety, and availability.

  18. Skeletal maturity assessment with the use of cone-beam computerized tomography.

    PubMed

    Joshi, Vajendra; Yamaguchi, Tetsutaro; Matsuda, Yukiko; Kaneko, Norikazu; Maki, Kotarou; Okano, Tomohiro

    2012-06-01

    The aim of the study was to compare cervical vertebrae maturity assessed with the use of cone-beam computerized tomography (CBCT) with the hand-wrist maturation method and cervical vertebrae maturation assessed with the use of lateral cephalography for the assessment of skeletal maturity. Assessment of skeletal maturation was done using skeletal maturity indicators (SMI) from hand-wrist radiography, cervical vertebrae maturity index (CVMI) from CBCT and lateral cephalography (cephalo-CVMI). The Spearman correlation coefficient was used for statistical analysis. We observed a significant relationship between CBCT-CVMI and cephalo-CVMI as well as between CBCT-CVMI and SMI stages. The Spearman correlation coefficient value between CBCT-CVMI and cephalo-CVMI was 0.975 (P < .0001) and between CBCT-CVMI and SMI was 0.961(P < .0001). Cervical vertebrae maturity assessment with CBCT provided a reliable assessment of pubertal growth spurt, and therefore CBCT can be used to assess skeletal maturity. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Survey radiography and computerized tomography imaging of the thorax in female dogs with mammary tumors

    PubMed Central

    2010-01-01

    Background Accurate early diagnosis of lung metastases is important for establishing therapeutic measures. Therefore, the present study aimed to compare survey thoracic radiographs and computerized tomography (CT) scans to specifically identify lung metastases in female dogs with mammary tumors. Methods Twenty-one female dogs, weighing 3 to 34 kg and aged from 5 years to 14 years and 10 months, with mammary tumors were studied. In all dogs before the imaging examinations, fine-needle aspiration cytology of the mammary tumors was performed to confirm the diagnosis. Three-view thoracic radiographs were accomplished: right lateral, left lateral and ventrodorsal views. Sequential transverse images of the thorax were acquired on a spiral Scanner, before and after intravenous bolus injection of nonionic iodine contrast. Soft-tissue and lung windows were applied. All the mammary tumors were surgically removed and examined histologically. Results The correlation between the cytological and histological results regarding presence of malignancy was observed in only 17 cases. In radiographic examinations, no dog displayed signs of lung metastases or thorax chest lesions. CT detected lung metastasis in two cases, while small areas of lung atelectasis located peripherally were found in 28.57% of the dogs. Conclusion In this study population, spiral CT showed higher sensitivity than chest radiographies to detect lung metastasis; this indicates that CT should be performed on all female dogs with malignant mammary tumors. PMID:20214816

  20. Checking the possibility of controlling fuel element by X-ray computerized tomography

    NASA Astrophysics Data System (ADS)

    Trinh, V. B.; Zhong, Y.; Osipov, S. P.; Batranin, A. V.

    2017-08-01

    The article considers the possibility of checking fuel elements by X-ray computerized tomography. The checking tasks are based on the detection of particles of active material, evaluation of the heterogeneity of the distribution of uranium salts and the detection of clusters of uranium particles. First of all, scheme of scanning improve the performance and quality of the resulting three-dimensional images of the internal structure is determined. Further, the possibility of detecting clusters of uranium particles having the size of 1 mm3 and measuring the coordinates of clusters of uranium particles in the middle layer with the accuracy of within a voxel size (for the considered experiments of about 80 μm) is experimentally proved in the main part. The problem of estimating the heterogeneity of the distribution of the active material in the middle layer and the detection of particles of active material with a nominal diameter of 0.1 mm in the “blank” is solved.

  1. Computerized tomography evaluation of a resorbable implant after transforaminal lumbar interbody fusion.

    PubMed

    Kuklo, Timothy R; Rosner, Michael K; Polly, David W

    2004-03-15

    Synthetic bioabsorbable implants have recently been introduced in spinal surgery; consequently, the indications, applications, and results are still evolving. The authors used absorbable interbody spacers (Medtronic Sofamor Danek, Memphis, TN) packed with recombinant bone morphogenetic protein (Infuse; Medtronic Sofamor Danek) for single- and multiple-level transforaminal lumbar interbody fusion (TLIF) procedures over a period of 18 months. This is a consecutive case series in which postoperative computerized tomography (CT) scanning was used to assess fusion status. There were 22 patients (17 men, five women; 39 fusion levels) whose mean age was 41.6 years (range 23-70 years) and in whom the mean follow-up duration was 12.4 months (range 6-18 months). Bridging bone was noted as early as the 3-month postoperative CT scan when obtained; solid arthrodesis was routinely noted between 6 and 12 months in 38 (97.4%) of 39 fusion levels. In patients who underwent repeated CT scanning, the fusion mass appeared to increase with time, whereas the disc space height remained stable. Although the results are early (mean 12-month follow-up duration), there was only one noted asymptomatic delayed union/nonunion at L5-S1 in a two-level TLIF with associated screw breakage. There were no infections or complications related to the cages. The bioabsorbable cages appear to be a viable alternative to metal interbody spacers, and may be ideally suited to spinal interbody applications because of their progressive load-bearing properties.

  2. Diagnostic Value of Dual-Source Computerized Tomography Combined with Perfusion Imaging for Peripheral Pulmonary Embolism

    PubMed Central

    Mao, Xijin; Wang, Shanshan; Jiang, Xingyue; Zhang, Lin; Xu, Wenjian

    2016-01-01

    Background Pulmonary embolism has become the third most common cardiovascular disease, which can seriously harm human health. Objectives To investigate the diagnostic value of dual-source computerized tomography (CT) and perfusion imaging for peripheral pulmonary embolism. Patients and Methods Thirty-two patients with suspected pulmonary embolism underwent dual-source CT exams. To compare the ability of pulmonary embolism detection software (PED) with CT pulmonary angiography (CTPA) in determining the presence, numbers, and locations of pulmonary emboli, the subsequent images were reviewed by two radiologists using both imaging modalities. Also, the diagnostic consistency between PED and CTPA images and dual-energy pulmonary perfusion imaging (DEPI) for segmental pulmonary embolism was compared. Results CTPA images revealed 50 (7.81%) segmental and 56 (4.38%) sub-segmental pulmonary embolisms, while the PED images showed 68 (10.63%) segmental and 94 (7.34%) sub-segmental pulmonary embolisms. Thus, the detection rate on PED images for peripheral pulmonary embolism was significantly higher than that of the CTPA images (P < 0.05). There was good consistency for diagnosing segmental pulmonary embolism between PED and CTPA and DEPI (kappa = 0.85). The sensitivity and specificity of DEPI images for the diagnosis of pulmonary embolism were 91.7% and 97.5%, respectively. Conclusion PED software of dual-source CT combined with perfusion imaging can significantly improve the detection rate of peripheral pulmonary embolism. PMID:27703656

  3. VEGF facilitates periosteal distraction-induced osteogenesis in rabbits: a micro-computerized tomography study.

    PubMed

    Casap, Nardy; Venezia, Nuphar Blau; Wilensky, Asaf; Samuni, Yuval

    2008-02-01

    Distraction osteogenesis is routinely used for reconstruction of bone. Conversely, it was hypothesized that mechanical traction of the periosteum would induce bone formation, and hence the use of periosteal distraction for induction of osteogenesis has been proposed. Further, it was postulated that intracallus administration of vascular endothelial growth factor (VEGF) would facilitate osteogenesis. To investigate this hypothesis, formation of newly synthesized bone was evaluated using micro-computerized tomography (microCT) and histomorphometry. Periosteal distractors were placed subperiosteally in one side of the mandible of rabbits, whereas the contralateral served as control. One group of animals received VEGF into the forming callus. Formation of bone was measured using microCT and histological analysis. The results demonstrate formation of new bone following periosteal distraction. Addition of VEGF to the distraction site increased bone synthesis. microCT and histological analysis validate the hypothesis that mechanical distraction of the periosteum induces osteogenesis and that VEGF has a positive effect on osteogenesis. Periosteal distraction is emerging as a reliable technique for bone regeneration.

  4. Numerical Modeling of Jointed Rock Under Compressive Loading Using X-ray Computerized Tomography

    NASA Astrophysics Data System (ADS)

    Yu, Qinglei; Yang, Shengqi; Ranjith, P. G.; Zhu, Wancheng; Yang, Tianhong

    2016-03-01

    As jointed rocks consist of joints embedded within intact rock blocks, the presence and geometrical fabric of joints have a great influence on the mechanical behavior of rock. With consideration of the actual spatial shape of joints, a numerical model is proposed to investigate the fracture evolution mechanism of jointed rocks. In the proposed model, computerized tomography (CT) scanning is first used to capture the microstructure of a jointed sandstone specimen, which is artificially fabricated by loading the intact sample until the residual strength, and then digital image processing (DIP) techniques are applied to characterize the geometrical fabric of joints from the CT images. A simple vectorization method is used to convert the microstructure based on a cross-sectional image into a layer of 3-D vectorized microstructure and the overall 3-D model of the jointed sandstone including the real spatial shape of the joints is established by stacking the layers in a specific sequence. The 3-D model is then integrated into a well-established code [three-dimensional Rock Failure Process Analysis, (RFPA3D)]. Using the proposed model, a uniaxial compression test of the jointed sandstone is simulated. The results show that the presence of joints can produce tensile stress zones surrounding them, which result in the fracture of jointed rocks under a relatively small external load. In addition, the spatial shape of the joints has a great influence on the fracture process of jointed rocks.

  5. The use of computerized tomography in determining stature and sex from metatarsal bones.

    PubMed

    Rodríguez, Sonia; González, Antonio; Simón, Antía; Rodríguez-Calvo, María S; Febrero-Bande, Manuel; Cordeiro, Cristina; Muñoz-Barús, José I

    2014-09-01

    This study evaluates the efficacy of a radiological method to estimate stature from measurements of the first and second metatarsal taken from a collection of metatarsals of a Portuguese Caucasian population in which the measurements were made directly on the bone. The highest coefficient of determination and the lowest standard error were obtained with the physiological length of the second metatarsal (F2), using the equation S=895.4803+10.7848F2. The linear regressions obtained show significant differences between the estimated heights from M1. In addition, we offer a simple method for sex determination based on the maximum length (M1) and width (W1) of the first metatarsal, where W1=x1; (M1/W1)=x2; β0=55.4767; β1=-2.5796 and β2=-4.6898. Here we present a method of measurement using computerized tomography that enables population studies using live volunteers without incurring the difficulties of on the bone measurement. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  6. Volumetric computerized tomography as a measurement of periprosthetic acetabular osteolysis and its correlation with wear

    PubMed Central

    Looney, R John; Boyd, Allen; Totterman, Saara; Seo, Gwy-Suk; Tamez-Pena, Jose; Campbell, Debbie; Novotny, Leonore; Olcott, Christopher; Martell, John; Hayes, F Ann; O'Keefe, Regis J; Schwarz, Edward M

    2002-01-01

    Osteolysis, which is considered to be a major source of morbidity following total hip joint replacement, has been notoriously difficult to measure accurately, particularly in the acetabular area. In order to study periacetabular osteolysis, specialized software for computerized tomography (CT) scan image analysis has been developed. This software (3D-CT) eliminates metal artifacts, allows three-dimensional segmentation of the CT image, and reconstructs the segmented image to provide an accurate representation and measurement of volume for osteolytic lesions. In the present study, 20 patients underwent periacetabular osteolytic volume determination using 3D-CT, functional assessment (using the Harris Hip Scale, the Western Ontario and McMaster University Osteoarthritis Index, and the short form 36 questionnaire), and two-dimensional analysis of volumetic polyethylene wear using digitalized plain films. Periacetabular osteolysis correlated directly with the polyethylene wear rate (relative risk [RR] = 0.494, P = 0.027). If one patient with an acetabular revision, one patient with recurrent dislocation, and one patient with a Biomet prosthesis are excluded, then the correlation between wear and osteolysis is improved (RR = 0.685, P = 0.002). In summary, the current study demonstrates both the feasibility of CT imaging of periacetabular osteolysis and the correlation between polyethylene wear and osteolytic volume, providing a potential outcome measure for clinical trials that are designed to examine interventions in this complex disease process. PMID:11879538

  7. Diagnostic value of unenhanced computerized tomography urography in the evaluation of acute renal colic.

    PubMed

    Wang, Jia-Hwia; Lin, Wen-Chiung; Wei, Chao-Jung; Chang, Cheng-Yen

    2003-10-01

    This study prospectively evaluated the diagnostic value of unenhanced computerized tomography (CT) urography in patients with acute renal colic. Fifty-nine patients with clinical manifestations of acute renal colic underwent unenhanced helical CT to evaluate urinary tract abnormalities. Reformatted three-dimensional CT urography was performed in all patients. The findings were correlated with ureteroscopy, surgical findings, histopathologic findings, and clinical course. CT urography detected urinary abnormalities in 57 of 59 patients with the clinical manifestation of acute renal colic, including 45 cases of urolithiasis, three urinary malignancies, one congenital abnormality, and eight ureteral strictures (due to chronic inflammation or fibrosis). CT urography showed negative findings in the urinary system in two patients, and after clinical follow-up, urinary abnormality was excluded in these patients. Incidental findings of extrarenal disease were noted in six patients (pulmonary abnormalities, n = 2; gallstones, n = 4). Only one patient with urolithiasis was misdiagnosed as having a renal tumor by CT urography. The sensitivity and specificity of CT urography in diagnosing urolithiasis was 97.8% (44/45) and 100% (14/14), respectively. Three-dimensional CT urography is a newly developed modality to evaluate anomalies of the urinary tract. The highly accurate diagnostic value of CT urography makes it a suitable alternative or substitutive modality in patients with acute flank pain.

  8. Contrast Dose and Radiation Dose Reduction in Abdominal Enhanced Computerized Tomography Scans with Single-phase Dual-energy Spectral Computerized Tomography Mode for Children with Solid Tumors.

    PubMed

    Yu, Tong; Gao, Jun; Liu, Zhi-Min; Zhang, Qi-Feng; Liu, Yong; Jiang, Ling; Peng, Yun

    2017-04-05

    Contrast dose and radiation dose reduction in computerized tomography (CT) scan for adult has been explored successfully, but there have been few studies on the application of low-concentration contrast in pediatric abdominal CT examinations. This was a feasibility study on the use of dual-energy spectral imaging and adaptive statistical iterative reconstruction (ASiR) for the reduction of radiation dose and iodine contrast dose in pediatric abdominal CT patients with solid tumors. Forty-five patients with solid tumors who had initial CT (Group B) and follow-up CT (Group A) after chemotherapy were enrolled. The initial diagnostic CT scan (Group B) was performed using the standard two-phase enhanced CT with 320 mgI/ml concentration contrast, and the follow-up scan (Group A) was performed using a single-phase enhanced CT at 45 s after the beginning of the 270 mgI/ml contrast injection using spectral mode. Forty percent ASiR was used for the images in Group B and monochromatic images with energy levels ≥60 keV in Group A. In addition, filtered back-projection (FBP) reconstruction was used for monochromatic images <60 keV in Group A. The total radiation dose, total iodine load, contrast injection speed, and maximum injection pressure were compared between the two groups. The 40 keV and 60 keV spectral CT images of Group A were compared with the images of Group B to evaluate overall image quality. The total radiation dose, total iodine load, injection speed, and maximum injection pressure for Group A were decreased by 19%, 15%, 34.4%, and 18.3%, respectively. The optimal energy level in spectral CT for displaying the abdominal vessels was 40 keV. At this level, the CT values in the abdominal aorta and its three branches, the portal vein and its two branches, and the inferior vena cava were all greater than 340 hounsfield unit (HU). The abdominal organs of Groups A and B had similar degrees of absolute and relative enhancement (t = 0.36 and -1.716 for liver, -0.153 and

  9. Eligibility for low-dose computerized tomography screening among asbestos-exposed individuals.

    PubMed

    Fitzgerald, Natalie R; Flanagan, William M; Evans, William K; Miller, Anthony B

    2015-07-01

    The study aimed to incorporate an estimate of risk for asbestos exposure in the Canadian Cancer Risk Management Lung Cancer (CRMM-LC) microsimulation model. In CRMM-LC, a 3-year probability of developing lung cancer can be derived from different risk profiles. An asbestos-exposed cohort was simulated and different scenarios of low-dose computerized tomography (LDCT) screening were simulated. As annual LDCT screening among non-asbestos-exposed individuals is less cost-effective than biennial screening, all the scenarios modeled for an asbestos-exposed cohort were biennial. For individuals with a two-fold risk of asbestos-induced lung cancer to be eligible for biennial LDCT screening, a smoking history of ≥15 pack-years would be necessary. For non-smokers with asbestos exposure resulting in a relative risk (RR) for lung cancer, it is not cost-effective to screen those with a RR of 5, but it is cost-effective to screen those with a RR of 10 (the heavily exposed). Asbestos-exposed individuals with an estimated two-fold or more risk of lung cancer from asbestos-exposure are eligible for LDCT screening at all ages from 55-74 years if they have a cigarette smoking history of ≥15 pack-years. Asbestos-exposed individuals who are lifelong non-smokers are eligible for LDCT screening at all ages from 55-74 years if they have accumulated a degree of asbestos exposure resulting in an estimated risk of lung cancer of ≥10.

  10. Toward a new insight of calcium oxalate stones in Drosophila by micro-computerized tomography.

    PubMed

    Chen, Wen-Chi; Chen, Huey-Yi; Liao, Po-Chi; Wang, Shih-Jing; Tsai, Ming-Yen; Chen, Yung-Hsiang; Lin, Wei-Yong

    2017-03-04

    We previously developed an animal model of calcium oxalate (CaOx) deposition on the Malphigian tubules of Drosophila melanogaster as a model of urolithiasis. Here, we introduce a new tool for the study of anatomical structure for Drosophila. As a consequence of technical development, the invention of micro-computerized tomography (CT) has been introduced to the small animal, such as rat and mice. We used Drosophila as a model organism and fed the flies 0.5% lithogenic agent ethylene glycol for 3 weeks. Samples were simply prepared for further scanned by micro-CT to scan samples at 800 nm resolution. CT scanning was performed at 40 kVp of voltage, 250 μA of current, and 1750 ms of exposure time and without filter. Reconstruction of sections was carried out with the GPU-based scanner software. Specific region of interests was further analyzed by DataViewer software. Area with high radiologic density level was defined as CaOx deposition for further 3D analysis. Image of whole lithogenic Drosophila was compared with control. High radiologic density level was detected in the region of Malphigian tubules which can be identified as CaOx stones. There was no stone image in the control group. The image was the same as human non-contrast CT for the diagnosis of stone disease. Micro-CT clearly demonstrated the calcium oxalate calcifications in the Malphigian tubules of fruit fly. The image system provides that a new vision on study animal will facilitate further study of stone disease. With the development of new technology on micro-CT, more delicate and advanced image will be presented in the future.

  11. Bisphosphonate-related osteonecrosis of the jaw: model and diagnosis with cone beam computerized tomography.

    PubMed

    Barragan-Adjemian, C; Lausten, L; Ang, D B; Johnson, M; Katz, J; Bonewald, L F

    2009-01-01

    Intravenous bisphosphonate (BP) therapy has become the standard of care for the treatment of cancers that metastasize to bone. BPs are associated with osteonecrosis of alveolar bones, a condition known as osteonecrosis of the jaw (ONJ). The incidence or pathogenesis of ONJ is largely unknown. The lesions are characterized by areas of exposed necrotic bone that do not heal after 8 weeks in the absence of radiation to the head and neck. ONJ lesions have been recalcitrant to conventional therapies. Lesions in cancer patients treated with BPs develop in association with periodontal disease, tooth extraction and/or in association with increased mechanical force due to partial/complete dentures. We hypothesized that intravenous BPs in cancer patients impair normal bone remodeling, thereby increasing the incidence of osteonecrotic lesions and that these lesions can be detected using cone beam computerized tomography (CBCT). From CBCTs taken at the University of Missouri at Kansas City School of Dentistry, 26 subjects had a cancer diagnosis and were on BP therapy. From these 26 subjects, 18 presented visible, exposed necrotic bone. We observed both sclerotic and radiolucent lesions. Lesions could be detected and measured in reconstructed images where most were found to expand to large areas of the bone. We were able to identify necrotic bodies or 'involucrums' within the ONJ lesions, suggesting that this could be the mechanism for the formation of a clinically visible sequestrum. We propose that CBCT can potentially identify and follow the progression of both pre- and postclinical lesions in ONJ patients, allowing better diagnosis and assessment of disease status. Copyright 2008 S. Karger AG, Basel.

  12. [Computerized transverse axial tomography in intracerebral, intracerebellar and intraventricular hemorrhage (author's transl)].

    PubMed

    Yamamoto, M; Imanaga, H; Jimbo, M; Kitamura, K

    1977-04-01

    Computerized transverse axial tomography (CT) of the brain is a recently developed method which allows non-invasive roentgenologic evaluation of intracranial diseases. The advent of CT represents a great advance in the diagnosis of a very wide variety of intracranial lesions, including cerebrovascular diseases. Especially, CT was found to be extremely informative in evaluating intracerebral, intracerebellar and intraventricular hemorrhage. The purpose of this report is to evaluate the clinical usefulness of CT in the diagnosis of intracranial hemorrhage. From the seven hundreds cases of various intracranial diseases hitherto examined by the EMI-scanner (160 X 160 matrix), twenty-three cases of nontraumatic intracranial hemorrhage were selected for the present study. Fifteen cases of fresh hemorrhage consisted of hypertensive cerebrovascular disease, arterio-venous malformation, aneurysm and unknown etiology, number of cases being six, three, four and two, respectively. All cases were examined within fifteen days after the ictus and the positive findings were obtained in all cases. The characteristic feature of the hematoma is the circumscribed and increased density area surrounded by the decreased density zone probably representing the accompanied brain edema. The sequential CT studies revealed that the hematoma area was gradually decreased in its density and finally transformed into the rather low density one in four weeks or so after the ictus. The smallest hematoma detected by CT was the cerebellar hematoma about five grams in weight, which was failed to be recognized by the angiography. In cases of the old hemorrhage, besides the decreased density area of the hematoma, such findings were obtained as cerebral atrophy, ventricular dilatation and porencephalic change. It would be concluded that CT study is the most useful aid at present available in the diagnosis of intracranial hemorrhage. The precise anatomic extent of the hematoma, associated brain edema

  13. Computerized tomography in the workup of pediatric appendicitis: why are children scanned?

    PubMed

    Ladd, Mitchell R; Neff, Lucas P; Becher, Robert D; Gallaher, Jared R; Pranikoff, Thomas

    2012-06-01

    Physicians increasingly use computerized tomography (CT) for the evaluation of suspected acute appendicitis (AA) in children despite increasing awareness of the potential dangers of CT-associated radiation exposure. Many studies demonstrate the value of CT in the diagnosis of AA, but none have determined what factors influence the decision to perform a CT. We investigated factors associated with the use of CT during initial workup of children who subsequently underwent appendectomy. This is a retrospective review of all patients aged 0 to 17 years who underwent appendectomy for AA by pediatric surgeons over 11 years. Both univariate and multivariable logistic regression models were created to predict use of CT. A total of 546 children underwent appendectomy for AA, of which 293 (53%) underwent CT. In univariate analysis, seven variables were significantly associated with the use of CT: female gender, Hispanic ethnicity, initial presentation to referring hospitals, lower Alvarado scores, delays from onset of symptoms to hospital presentation, migration, and rebound tenderness. In multivariable analysis, four variables significantly independently predicted the use of CT: initial presentation to a referring hospital [odds ratio (OR) 3.50), female gender (OR 1.49), increased latency from symptom onset to presentation (OR 1.34), and the presence of rebound tenderness (OR 0.23), which had a protective effect; the overall model was statistically significant (P < 0.0001). This model is the first to define variables that significantly predict CT utilization in the pediatric population. Continued investigation will be necessary to develop effective algorithms for judicious use of CT for suspected AA.

  14. Characterizing analogue caldera collapse with computerized X-ray micro-tomography

    NASA Astrophysics Data System (ADS)

    Poppe, Sam; Holohan, Eoghan; Boone, Matthieu; Pauwels, Elin; Cnudde, Veerle; Kervyn, Matthieu

    2013-04-01

    Analogue models in the past mainly explored caldera collapse structures by documenting 2D model cross-sections. Kinematic aspects and 3D structures of caldera collapse are less well understood, although they are essential to interpret recent field and monitoring data. We applied high resolution radiography and computerized X-ray micro-tomography (µCT) to image the deformation during analogue fluid withdrawal in small-scale caldera collapse models. The models test and highlight the possibilities and limitations of µCT-scanning to qualitatively image and quantitatively analyse deformation of analogue volcano-tectonic experiments. High resolution interval radiography sequences document '2.5D' surface and internal model geometry, and subsidence kinematics of a collapsing caldera block into an emptying fluid body in an unprecedented way. During the whole drainage process, all subsidence was bound by caldera ring faults. Subsidence was associated with dilatation of the analogue granular material within the collapsing column. The temporal subsidence rate pattern within the subsiding volume comprised three phases: 1) Upward ring fault propagation, 2) Rapid subsidence with the highest subsidence rates within the uppermost subsiding volume, 3) Relatively slower subsidence rates over the whole column with intermittent subsidence rate acceleration. Such acceleration did almost never affect the whole column. By using radiography sequences it is possible in a non-destructive manner to obtain a continuous observation of fault propagation, down sag mechanisms and the subsequent development of collapse structures. Multi-angle µCT scans of the collapse result allow for a full virtual 3D reconstruction of the model. This leads to an unprecedented 3D view on fault geometries. The developed method is a step towards the quantitative documentation of volcano-tectonic models that would render data interpretations immediately comparable to monitoring data available from recent

  15. Surgical strategy for Apert syndrome: Retrospective study of developmental quotient and three-dimensional computerized tomography.

    PubMed

    Tomita, Shoichi; Miyawaki, Takeshi; Nonaka, Yuichirou; Sakai, Shinsuke; Nishimura, Reiji

    2017-07-01

    There are many surgical techniques for craniosynostosis. However, the indications for and timing of surgery still remain unclarified. Most of the skull growth in craniosynostosis is completed in the first year, and the bone is strong enough to undergo distraction osteogenesis. However, previous reports showed that patients operated on before 1 year of age had better IQ than those operated later in life. This report aims to consider the best timing for cranial expansion and surgical strategy for Apert syndrome. From January 2002 to December 2011, 13 patients with Apert syndrome were operated on and were followed up for more than 5 years. Nine patients underwent operations before 1 year of age (early surgery group) and three patients underwent operations later in life (late surgery group). They underwent fronto-orbital advancement for primary surgery. We evaluated postoperative developmental quotient every year and cephalic index (CI) measured by three-dimensional computerized tomography (3D-CT) at the age over 5 years retrospectively. Eleven of 13 patients improved their developmental quotient scores, with no significant intergroup differences. The CI evaluation showed cases with remnant brachycephalic deformity in both groups. Two patients with remnant plagiocephalic deformities tend to have primary surgery early in life compared to the others. Thus the delay in primary surgery had little influence on psychological development. We conclude that the primary surgery can be delayed unless the intracranial pressure needs to be controlled. In addition, fronto-orbital advancement could not sufficiently improve the brachycephalic appearance, other procedures like posterior vault distraction might be better alternatives. © 2017 Japanese Teratology Society.

  16. Combining ultrasonography and noncontrast helical computerized tomography to evaluate Holmium laser lithotripsy

    PubMed Central

    Mi, Jia; Li, Jie; Zhang, Qinglu; Wang, Xing; Liu, Hongyu; Cao, Yanlu; Liu, Xiaoyan; Sun, Xiao; Shang, Mengmeng; Liu, Qing

    2016-01-01

    Abstract The purpose of the study was to establish a mathematical model for correlating the combination of ultrasonography and noncontrast helical computerized tomography (NCHCT) with the total energy of Holmium laser lithotripsy. In this study, from March 2013 to February 2014, 180 patients with single urinary calculus were examined using ultrasonography and NCHCT before Holmium laser lithotripsy. The calculus location and size, acoustic shadowing (AS) level, twinkling artifact intensity (TAI), and CT value were all documented. The total energy of lithotripsy (TEL) and the calculus composition were also recorded postoperatively. Data were analyzed using Spearman's rank correlation coefficient, with the SPSS 17.0 software package. Multiple linear regression was also used for further statistical analysis. A significant difference in the TEL was observed between renal calculi and ureteral calculi (r = –0.565, P < 0.001), and there was a strong correlation between the calculus size and the TEL (r = 0.675, P < 0.001). The difference in the TEL between the calculi with and without AS was highly significant (r = 0.325, P < 0.001). The CT value of the calculi was significantly correlated with the TEL (r = 0.386, P < 0.001). A correlation between the TAI and TEL was also observed (r = 0.391, P < 0.001). Multiple linear regression analysis revealed that the location, size, and TAI of the calculi were related to the TEL, and the location and size were statistically significant predictors (adjusted r2 = 0.498, P < 0.001). A mathematical model correlating the combination of ultrasonography and NCHCT with TEL was established; this model may provide a foundation to guide the use of energy in Holmium laser lithotripsy. The TEL can be estimated by the location, size, and TAI of the calculus. PMID:27930563

  17. The lymph drainage pattern of the mammary glands in the cat: a lymphographic and computerized tomography lymphographic study.

    PubMed

    Papadopoulou, P L; Patsikas, M N; Charitanti, A; Kazakos, G M; Papazoglou, L G; Karayannopoulou, M; Chrisogonidis, I; Tziris, N; Dimitriadis, A

    2009-08-01

    Seventy-three clinically normal, lactating cats were used to investigate the lymph drainage of 73 mammary glands. In 50 cats of the first group, the number of lymphatic vessels emerging from the examined mammary gland, their course and the lymph nodes into which they are drained were studied by indirect lymphography (IL) after intramammary injection of an oily contrast medium. In 23 cats of the second group, the lymph drainage of the mammary glands was studied by computerized tomography indirect lymphography (CT-IL) after intramammary injection of a water soluble contrast medium. The following day, the lymph drainage of the mammary gland examined by CT-IL was studied by IL, as it was described in the first group, for comparison purposes. The main conclusions drawn after this study were as follows: lymph drains from the first and second mammary glands with one or rarely two or three lymphatic vessels to the accessory axillary lymph nodes. Lymph drains from the third mammary gland with one or two and rarely three lymphatic vessels usually to the accessory inguinal lymph nodes or to the accessory axillary lymph nodes. In some cases, it drains to both lymph nodes simultaneously or it may rarely drain only to the medial iliac lymph nodes. The fourth mammary gland with one or two and rarely three lymphatic vessels usually drains to the accessory inguinal lymph nodes. It may rarely drain only to the medial iliac lymph nodes. Mammary lymphatic vessels that cross the midline and lymphatic connection between the mammary glands were not demonstrated. No differences in the mammary lymph drainage pattern between IL and CT-IL were found.

  18. X-ray computerized tomography analysis and density estimation using a sediment core from the Challenger Mound area in the Porcupine Seabight, off Western Ireland

    NASA Astrophysics Data System (ADS)

    Tanaka, Akiko; Nakano, Tsukasa; Ikehara, Ken

    2011-02-01

    X-ray computerized tomography (CT) analysis was used to image a half-round core sample of 50 cm long recovered from near Challenger Mound in the Porcupine Seabight, off western Ireland during the Integrated Ocean Drilling Program Expedition 307. This allowed three-dimensional examination of complex shapes of pebbles and ice-rafted debris in sedimentary sequences. X-ray CT analysis was also used for the determination of physical properties; a comparison between bulk density by the mass-volume method and estimated density based on linear attenuation coefficients of X-ray CT images provides insight into a spatially detailed and precise map of density variation in samples through the distribution of CT numbers.

  19. A Method for the Comparison of Item Selection Rules in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Barrada, Juan Ramon; Olea, Julio; Ponsoda, Vicente; Abad, Francisco Jose

    2010-01-01

    In a typical study comparing the relative efficiency of two item selection rules in computerized adaptive testing, the common result is that they simultaneously differ in accuracy and security, making it difficult to reach a conclusion on which is the more appropriate rule. This study proposes a strategy to conduct a global comparison of two or…

  20. A Method for the Comparison of Item Selection Rules in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Barrada, Juan Ramon; Olea, Julio; Ponsoda, Vicente; Abad, Francisco Jose

    2010-01-01

    In a typical study comparing the relative efficiency of two item selection rules in computerized adaptive testing, the common result is that they simultaneously differ in accuracy and security, making it difficult to reach a conclusion on which is the more appropriate rule. This study proposes a strategy to conduct a global comparison of two or…

  1. Prediction of coma and anisocoria based on computerized tomography findings in patients with supratentorial intracerebral hemorrhage.

    PubMed

    Song, Zhi; Zheng, Wen; Zhu, Haixia; Chen, Yiwei; Fan, Xuejun; Hou, Deren; Deng, Hao

    2012-07-01

    Coma and anisocoria are the two common signs of a crucial state of neurological dysfunction. The ability to forecast the occurrence of these conditions would help clinicians make clinical risk assessments and decisions. From October 2006 to September 2008, 118 patients with supratentorial intracerebral hemorrhage (SICH) were enrolled in this retrospective investigation. Patients were distributed into 3 groups according to occurrence of the signs of coma and/or anisocoria in the observation unit during a 30-day period. Group 1 included 52 patients who had normal or impaired consciousness, group 2 included 27 patients who had coma with no anisocoria and group 3 consisted of 39 patients who had coma with anisocoria. The clinical characteristics and parameters on computerized tomography (CT) findings were compared using univariate analysis to determine the factors that were related to the level of consciousness. Logistic regression models established the predictive equations for coma and anisocoria. Univariate analysis revealed that hematoma volume, the score of intraventricular hemorrhage (IVH score) and the amplitude of midline shift were the factors related to coma and anisocoria. Mean hematoma volume was 24.0 ± 13.0 ml, 53.6 ± 12.6 ml and 80.5 ± 24.6 ml, the mean amplitudes of midline shift were 1.3 ± 2.0 mm, 5.9 ± 4.9 mm and 10.1 ± 5.5 mm, and the mean IVH score was 0.8 ± 1.3, 3.3 ± 3.3 and 5.9 ± 3.4 in groups 1, 2 and 3, respectively. Multivariate analysis showed that hematoma volume and IVH score were independent prognostic factors for coma and anisocoria. The predictive equations for coma and anisocoria were LogitP = 0.279X(HV) + 0.521X(IVH)-18.164 and LogitP = 0.125X(HV)+0.326X(IVH)-6.864, respectively. Hematoma volume and IVH score were the independent prognostic factors for coma and anisocoria. Logistic regression models established the fitted predictive equations, which could help clinicians make clinical risk assessments and decisions. Crown

  2. Computerized Tomography-Based Morphologic and Morphometric Features of the Coccyx Among Arab Adults.

    PubMed

    Marwan, Yousef Abbas; Al-Saeed, Osama Mhawes; Esmaeel, Ali Abdulla; Ahmad Kombar, Osama Rabie; Bendary, Abdulla Mohammad; Abdul Azeem, Mokhtar Elsayed

    2014-07-09

    Study Design. Cross-sectional, retrospective.Objective. To identify morphologic and morphometric features of the coccyx among adult Arabs.Summary of Background Data. Different sacrococcygeal morphologic features were found to be associated with coccydynia.Methods. Review of 202 computerized tomography scans of adult Arab subjects was done (mean age: 47.98 ± 16.46 years). Sacrococcygeal morphologic features including number of coccygeal segments, type of coccyx, joint fusion, joint subluxation, coccygeal spicule, coccygeal sacralization, ventral angulation of the terminal sacral segment (S5), and lateral deviation of coccygeal tip were recorded. Moreover, morphometric measurements including lengths and angles of the sacrococcygeal region were measured. Analysis of data was carried out using p-value of <0.05 as the cut-off level of significance.Results. Three coccygeal segments were present in 138 (68.3%) of individuals. The majority of the subjects had coccyx type I (96; 47.5%), II (70; 34.7%) or III (31; 15.3%); type I being more common among males (p = 0.004). Bony spicule was present in 109 (54.0%) individuals. Joint fusion, joint subluxation, coccygeal sacralization, ventral angulation of S5 and lateral deviation of coccygeal tip were present in 38.6%, 31.7%, 34.2%, 38.1% and 38.6% of the subjects respectively. Joint subluxation and ventral angulation of S5 were significantly more present among females (p = 0.015, p = 0.014 respectively). The mean straight and curved lengths of the coccyx were 3.3 ± 0.7 cm and 3.7 ± 0.8 cm respectively. The sacrococcygeal structures were longer in men than women. The mean sacrococcygeal joint angle was 149.2° ± 28.1°. Based on the morphometric measurements, the coccyx was more ventrally angulated among females.Conclusions. The coccygeal morphology and morphometry of Arab adults share some similarities and differences with individuals of other ethnic backgrounds. Future studies should investigate the relation between these

  3. In vivo determination of urinary stone composition using dual energy computerized tomography with advanced post-acquisition processing.

    PubMed

    Zilberman, D E; Ferrandino, M N; Preminger, G M; Paulson, E K; Lipkin, M E; Boll, D T

    2010-12-01

    We assessed whether dual energy computerized tomography with advanced post-image processing can accurately differentiate urinary calculi composition in vivo. A total of 25 patients scheduled to undergo ureteroscopic/percutaneous nephrolithotomy were prospectively identified. Dual energy computerized tomography was performed using 64-slice multidetector computerized tomography. Novel post-processing (DECTSlope) used pixel by pixel analyses to generate data sets grayscale encoding ratios of relative differences in attenuation of low (DECT80 kVp) and high energy (DECT140 kVp) series. Surgical extraction and Fourier spectroscopy resulted in 82 calculi. Of these stones 51 showed minor admixtures (uric acid, ammonium urate, struvite, calcium oxalate monohydrate and brushite) and 31 were polycrystalline (mixtures of calcium oxalate monohydrate/dihydrate and calcium phosphate). Analyses identified stone clusters of equal composition and distinct attenuation descriptors on DECT140 kVp, DECT80 kVp and DECTSlope. Iterative cross-validation of the 3 dual energy computerized tomography data sets was used to identify characteristic attenuation limits for each stone type. Attenuatio profiles showed substantial overlap among various stones on DECT140 kVp (uric acid 427.3±168.1 HU, ammonium urate 429.9±99.7 HU, struvite 480.2±123.5 HU, calcium oxalate monohydrate 852.4±301.4 HU, brushite 863.7±180.1 HU and polycrystalline 858.1±210.5 HU) and on DECT80 kVp (uric acid 493.6±182.8 HU, ammonium urate 591.5±157.9 HU, struvite 712.4±173.9 HU, calcium oxalate monohydrate 1,240.5±494.7 HU, brushite 1,532.1±273.1 HU and polycrystalline 1,358.7±316.8 HU). Statistically spectral separation was not sufficient to characterize stones unambiguously based on DECT140 kVp/DECT80 kVp attenuation. Analysis of attenuation showed sufficient spectral separation on DECTSlope (uric acid 14.9±10.9 U, ammonium urate 56.1±1.8 U, struvite 42.7±1.4 U, calcium oxalate monohydrate 62.8±1.8 U and

  4. Regional model-based computerized ionospheric tomography using GPS measurements: IONOLAB-CIT

    NASA Astrophysics Data System (ADS)

    Tuna, Hakan; Arikan, Orhan; Arikan, Feza

    2015-10-01

    Three-dimensional imaging of the electron density distribution in the ionosphere is a crucial task for investigating the ionospheric effects. Dual-frequency Global Positioning System (GPS) satellite signals can be used to estimate the slant total electron content (STEC) along the propagation path between a GPS satellite and ground-based receiver station. However, the estimated GPS-STEC is very sparse and highly nonuniformly distributed for obtaining reliable 3-D electron density distributions derived from the measurements alone. Standard tomographic reconstruction techniques are not accurate or reliable enough to represent the full complexity of variable ionosphere. On the other hand, model-based electron density distributions are produced according to the general trends of ionosphere, and these distributions do not agree with measurements, especially for geomagnetically active hours. In this study, a regional 3-D electron density distribution reconstruction method, namely, IONOLAB-CIT, is proposed to assimilate GPS-STEC into physical ionospheric models. The proposed method is based on an iterative optimization framework that tracks the deviations from the ionospheric model in terms of F2 layer critical frequency and maximum ionization height resulting from the comparison of International Reference Ionosphere extended to Plasmasphere (IRI-Plas) model-generated STEC and GPS-STEC. The suggested tomography algorithm is applied successfully for the reconstruction of electron density profiles over Turkey, during quiet and disturbed hours of ionosphere using Turkish National Permanent GPS Network.

  5. Using computerized tomography to determine ionospheric structures. Part 1, Notivation and basic approaches

    SciTech Connect

    Vittitoe, C.N.

    1993-08-01

    Properties of the ionosphere are reviewed along with its correlations with other geophysical phenomena and with applications of ionospheric studies to communication, navigation, and surveillance systems. Computer tomography is identified as a method to determine the detailed, three-dimensional distribution of electron density within the ionosphere. Several tomography methods are described, with a basic approach illustrated by an example. Limitations are identified.

  6. An evaluation of the condylar position of the temporomandibular joint by computerized tomography in Class III malocclusions: a preliminary study.

    PubMed

    Seren, E; Akan, H; Toller, M O; Akyar, S

    1994-05-01

    The position of the condyle within the glenoid fossa was investigated in 21 adult patients with untreated skeletal Class III relationships and 18 adult patients with normal occlusions as controls. Axial computerized tomography (CT) was used for precise measurements of the bony structures of the temporamandibular joints. In horizontal sections, the mediolateral dimensions of the condyles of the patient group were found to be statistically higher in the fossa. The anteroposterior glenoid fossa dimensions were found to be smaller in Class III malocclusions. The smaller anterior joint space dimensions in the Class III relationships were also found to be statistically significant. The analysis of the measurements suggests that relative condylar protrusion with a relative mediolateral elongation of the condyle within a relatively smaller glenoid fossa are correlated with the anterior mandibular displacement in skeletal Class III malocclusions.

  7. Diagnosis and management decisions in infections of the deep fascial spaces of the head and neck utilizing computerized tomography.

    PubMed

    Endicott, J N; Nelson, R J; Saraceno, C A

    1982-06-01

    Infections of the deep spaces of the head and neck may still result in major consequences despite the advent of antibiotics. Abscesses in these areas merit special consideration by today's head and neck surgeon because of their relative rarity and the life-threatening complications that may follow inadequate treatment. Diagnosis and management decisions are enhanced by use of computerized tomography (CT) as an adjunctive study. The EMI scan may demonstrate either cellulitis of the neck requiring no surgery or a space abscess displacing the adjacent structures thus requiring surgical drainage. Anatomy of the significant fascial planes and spaces of the neck will reviewed employing CT utilizing 3 mm cuts. Specific case presentations feature early diagnosis and management.

  8. Rare bilateral C6 spondylolysis and spondylolisthesis in an adolescent athlete: evaluation with magnetic resonance imaging and multidetector computerized tomography.

    PubMed

    Amin, Mohammed F; Mollano, Anthony V; Weinstein, Stuart L; El-Khoury, George Y

    2006-10-01

    Case report. To show a rare case of cervical spondylolysis and spondylolisthesis secondary to bilateral stress fractures at the pedicle laminar junction of C6 in a 16-year-old athlete playing high school baseball. The patient presented with 3 months of neck pain and intermittent right arm radicular symptoms. Plain radiographs and multidetector computerized tomography (CT) of the cervical spines. Plain radiographs revealed loss of lower cervical lordosis. Multidetector CT indicated bilateral C6 spondylolysis. Magnetic resonance imaging showed bilateral marrow edema at the pedicle laminar junction of C6. Treatment included placing his neck in a Philadelphia collar for 6 weeks. Follow-up CT revealed progression of healing. Early diagnosis and appropriate management of these cases are important to promote healing.

  9. Evaluation of the effects of functional orthopaedic treatment on temporomandibular joints with single-photon emission computerized tomography.

    PubMed

    Güner, D D; Oztürk, Y; Sayman, H B

    2003-02-01

    The aims of this investigation were to evaluate the temporomandibular joints (TMJs) with single-photon emission computerized tomography (SPECT) in subjects treated with a mandibular advancement repositioning splint (MARS), and to compare the results with the total effect on dento-facial morphology. The study was undertaken on 17 Class II division 1 malocclusion subjects (nine males, eight females) with mandibular retrusion. Ten patients (five males, five females) formed the treatment group and seven (four males, three females) were used as the control. SPECT was performed only in the treatment group. Cephalometric evaluation showed significant increases in NAPog (P < 0.001) and SNB (P < 0.05) angles. Increased bone formation in theTMJs was analysed with the aid of pre- and post-treatment scintigraphic studies. The results indicate that new bone formation in the mandibular condyles seems to contribute to the increase in mandibular prognathism resulting from functional jaw orthopaedics.

  10. Magnetic resonance imaging and computerized tomography of a gravid leopard tortoise (Geochelone pardalis pardalis) with metabolic bone disease.

    PubMed

    Raiti, P; Haramati, N

    1997-06-01

    Secondary nutritional metabolic bone disease was diagnosed in a gravid leopard tortoise (Geochelone pardalis pardalis). Diagnosis was based upon history, physical examination, hematology, plasma biochemistry, and radiography. Despite induced oviposition and treatment of metabolic bone disease for 8 wk, the tortoise's condition deteriorated. Repeat radiographs demonstrated gaseous intestinal distention. Oral administration of metoclopramide and mineral oil failed to stimulate defecation. Persistence of the ileus pattern prompted utilization of magnetic resonance imaging (MRI) and computerized tomography (CT). MRI demonstrated brightly enhanced loops of mineral oil-filled small bowel and preovulatory follicles. CT demonstrated dystrophic calcification of the left hepatic lobe and preovulatory follicles and the typical reticular pattern of chelonian lung. The interstitial septa were caused by pulmonary vasculature or bands of smooth muscle.

  11. [Role of computeric tomography and magnetic resonance imaging in diagnosis of inflammatory diseases of sacro-ileal joint].

    PubMed

    Baĭramov, R B

    2012-05-01

    Sensitivity of computeric tomography (CT) and magnetic resonance imaging (MRI) for sacroileitis diagnosis was studied, optimal for MRI investigation was established. In 31 patients, owing obvious clinical signs of inflammatory sacroileitis (at average more than 5 mo duration of a low back pain) MRI of sacroiliac joint was conducted in a T1, T2 FS, 2D T2 FLASH regimes and after intravenous infusion of a contrast substance (gadolinium) - in a T1 FS regime, using system, owing a 1,5 T magnetic field intensity. The data obtained were compared with results of CT. Sacroileitis signs were revealed in 27 patients - according to CT data, and in 22 - MRI. CT have demonstrated as a more sensitive method of the bone erosion and sclerosis diagnosis, than MRI. MRI is more sensitive while revealing an active inflammatory process in the bone and joint space. While T1 FS application no additional information for sacroileitis diagnosis was obtained.

  12. Magnetic resonance imaging and computerized tomography in relation to the neurobehavioral sequelae of mild and moderate head injuries.

    PubMed

    Levin, H S; Amparo, E; Eisenberg, H M; Williams, D H; High, W M; McArdle, C B; Weiner, R L

    1987-05-01

    Twenty patients admitted for minor or moderate closed-head injury were studied to investigate the relationship between magnetic resonance imaging (MRI) and neurobehavioral sequelae. The MRI scans demonstrated 44 more intracranial lesions than did concurrent computerized tomography (CT) scans in 17 patients (85%); most of these lesions were located in the frontal and temporal regions. Estimates of lesion volume based on MRI were frequently greater than with CT; however, MRI disclosed no additional lesions that required surgical evacuation. Neuropsychological assessment during the initial hospitalization revealed deficits in frontal lobe functioning and memory that were related to the size and localization of the lesions as defined by MRI. Follow-up MRI and neuropsychological testing at 1 month (13 cases) and 3 months (six cases) disclosed marked reduction of lesion size paralleled by improvement in cognition and memory. These findings encourage further investigation of the prognostic utility of MRI for the clinical management and rehabilitation of mild or moderate head injury.

  13. Evaluation of the accuracy of Cone Beam Computerized Tomography (CBCT): medical imaging technology in head and neck reconstruction

    PubMed Central

    2013-01-01

    Background With the introduction, development and commercialization of Cone Beam Computerized Tomography (CBCT) technologies in the field of head and neck reconstruction, clinicians now have increased access to the technology. Given the growth of this new user group, there is an increasing concern regarding proper use, understanding, quality and patient safety. Methods The present study was carried out to evaluate data acquisition of CBCT medical imaging technology and the accuracy of the scanning at three different machine warming times. The study also compared the accuracy of CBCT at 0.2 mm slice thickness and Computerized Tomography (CT) at 1 mm slice thickness. A control model was CT scanned at five random intervals, at 1 mm slice thickness and CBCT scanned at specialized intervals, at 0.2 mm slice thickness. The data was then converted and imported into a software program where a digital registration procedure was used to compare the average deviations of the scanned models to the control. Results The study found that there was no statistically significant difference amongst the three CBCT machine warming times. There was a statistically significant difference between CT scanning with 1 mm slice thickness and CBCT scanning with 0.2 mm slice thickness. Conclusions The accuracy of the i-CAT CBCT scans used in the present study with a parameter at voxel size 0.2, will remain consistent and reliable at any warming stage. Also the difference between the CBCT i-CAT scans and the CT scans was not clinically significant based on suggested requirements of clinicians in head and neck reconstruction. PMID:23672880

  14. Repeatability of Computerized Tomography-Based Anthropomorphic Measurements of Frailty in Patients With Pulmonary Fibrosis Undergoing Lung Transplantation.

    PubMed

    McClellan, Taylor; Allen, Brian C; Kappus, Matthew; Bhatti, Lubna; Dafalla, Randa A; Snyder, Laurie D; Bashir, Mustafa R

    To determine interreader and intrareader repeatability and correlations among measurements of computerized tomography-based anthropomorphic measurements in patients with pulmonary fibrosis undergoing lung transplantation. This was an institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study of 23 randomly selected subjects (19 male and 4 female; median age = 69 years; range: 66-77 years) with idiopathic pulmonary fibrosis undergoing pulmonary transplantation, who had also undergone preoperative thoracoabdominal computerized tomography. Five readers of varying imaging experience independently performed the following cross-sectional area measurements at the inferior endplate of the L3 vertebral body: right and left psoas muscles, right and left paraspinal muscles, total abdominal musculature, and visceral and subcutaneous fat. The following measurements were obtained at the inferior endplate of T6: right and left paraspinal muscles with and without including the trapezius muscles and subcutaneous fat. Three readers repeated all measurements to assess intrareader repeatability. Intrareader repeatability was nearly perfect (interclass correlation coefficients = 0.99, P < 0.001). Interreader agreement was excellent across all 5 readers (interclass correlation coefficients: 0.71-0.99, P < 0.001). Coefficients of variance between measures ranged from 3.2%-6.8% for abdominal measurements, but were higher for thoracic measurements, up to 23.9%. Correlation between total paraspinal and total psoas muscle area was strong (r(2) = 0.67, P < 0.001). Thoracic and abdominal musculature had a weaker correlation (r(2) = 0.35-0.38, P < 0.001). Measures of thoracic and abdominal muscle and fat area are highly repeatable in patients with pulmonary fibrosis undergoing lung transplantation. Measures of muscle area are strongly correlated among abdominal locations, but inversely correlated between abdominal and thoracic

  15. Computerized Comparison and Analysis of Vincent van Gogh's Painting Brushstrokes

    NASA Astrophysics Data System (ADS)

    Wang, James Z.

    2009-03-01

    With advanced digitization techniques, museums have routinely begun to assemble vast digital libraries of images of their collections. These images can be analyzed by computers to assist art historians for a number of tasks. In our work, we focus on three challenges: artist identification, dating of an art work, and finding distinguishing features among artists. Two complementary approaches were taken: (1) the analysis of the geometric statistics based on the extracted individual brushstroke, and (2) the modeling of overall brushstroke texture. These approaches aim at assisting art historians in comparing a painting or parts of a painting to a group of paintings based on multiple criteria. Statistical methods have been used to compare groups of paintings. Each painting image is divided into subimages. Individual brushstrokes are segmented automatically. Geometric features, including the curvature, the overall orientation, and the size, are computed for each brushstroke. We also compute the features representing the interactivity of the brushstrokes extracted. The statistics, including average and standard deviation, of those features are used to model certain aspects of the artist's brushstrokes. For capturing the local brushstroke texture, we first apply a wavelet transform to the image. A spatial model, the 2-D hidden Markov model, is used to model the texture features of each subimage. The methods have shown to be able to distinguish van Gogh paintings and non van Gogh paintings to a great extent. The techniques can provide clues for the dating of van Gogh paintings. A comparison of the van Gogh paintings, Monticelli's paintings, and paintings by contemporary artists provides insights on their similarities and differences. The analysis has provided numerical statistics for further studying these and other paintings.

  16. Positron emission tomography/computerized tomography for tumor response assessment-a review of clinical practices and radiomics studies.

    PubMed

    Lu, Wei; Chen, Wengen

    2016-08-01

    Even with recent advances in cancer diagnosis and therapy, treatment outcomes for many cancers remain dismal. Patients often show different response to the same therapy regimen, supporting the development of personalized medicine. 18F-FDG PET/CT has been used routinely in the assessment of tumor response, in prediction of outcomes, and in guiding personalized treatment. These assessments are mainly based on physician's subjective or semi-quantitative evaluation. Recent development in Radiomics provides a promising objective way for tumor response assessment, which uses computerized tools to extract a large number of image features that capture additional information not currently used in clinic that has prognostic value. In this review, we summarized the clinical use of PET/CT and the PET/CT Radiomics studies for tumor response assessment. Finally, we discussed some challenges and future perspectives.

  17. Positron emission tomography/computerized tomography for tumor response assessment—a review of clinical practices and radiomics studies

    PubMed Central

    Lu, Wei; Chen, Wengen

    2016-01-01

    Even with recent advances in cancer diagnosis and therapy, treatment outcomes for many cancers remain dismal. Patients often show different response to the same therapy regimen, supporting the development of personalized medicine. 18F-FDG PET/CT has been used routinely in the assessment of tumor response, in prediction of outcomes, and in guiding personalized treatment. These assessments are mainly based on physician’s subjective or semi-quantitative evaluation. Recent development in Radiomics provides a promising objective way for tumor response assessment, which uses computerized tools to extract a large number of image features that capture additional information not currently used in clinic that has prognostic value. In this review, we summarized the clinical use of PET/CT and the PET/CT Radiomics studies for tumor response assessment. Finally, we discussed some challenges and future perspectives. PMID:27904837

  18. Tumor volume, luxury perfusion, and regional blood volume changes in man visualized by subtraction computerized tomography.

    PubMed

    Penn, R D; Walser, R; Kurtz, D; Ackerman, L

    1976-04-01

    Computer and photographic methods for producing subtractions of computerized axial tomographic (CAT) scans have been developed. By subtracting point for point a normal scan from one taken after intravenous infusion of contrast material, a picture of the contrast in the cerebral vessels is created. By this method, tumor size and degree of vascularity may be assessed. Furthermore, abnormalities in perfusion and changes in blood volume due to mass effects and edema may be detected. Subtracting scans should add to the diagnostic potential of CAT and provide a noninvasive way to study vascular changes in cerebral disease.

  19. Hodgkin lymphoma patients in first remission: routine positron emission tomography/computerized tomography imaging is not superior to clinical follow-up for patients with no residual mass.

    PubMed

    Dann, Eldad J; Berkahn, Leanne; Mashiach, Tatiana; Frumer, Michael; Agur, Ariel; McDiarmid, Bridgett; Bar-Shalom, Rachel; Paltiel, Ora; Goldschmidt, Neta

    2014-03-01

    There is no consensus regarding optimal follow-up mode for Hodgkin lymphoma (HL) patients that achieve complete remission following chemotherapy or combined chemo- and radiation therapy. Several studies demonstrated high sensitivity of positron emission tomography/computerized tomography (PET/CT) in detecting disease progression; however, these techniques are currently not recommended for routine follow-up. This retrospective study conducted in two Israeli (N = 291) and one New Zealand academic centres (N = 77), compared a group of HL patients, followed-up with routine imaging every 6 months during the first 2 years after achieving remission, once in the third year, with additional dedicated studies performed due to symptoms or physical findings (Group I) to a group of patients without residual masses who underwent clinically-based surveillance with dedicated imaging upon relapse suspicion (Group II). Five-year overall survival (OS) was 94% and median time to relapse was 8·6 months for both modes. Relapse rates in Groups I and II were 13% and 9%, respectively. During the first 3 years of follow-up, 47·5 and 4·7 studies were performed per detected relapse in Groups I and II, respectively. The current study demonstrated no benefit in either progression-free survival (PFS) or OS in HL patients followed by routine imaging versus clinical follow-up. The cost was 10 times higher for routine imaging. © 2013 John Wiley & Sons Ltd.

  20. The potential of positron emission tomography/computerized tomography (PET/CT) scanning as a detector of high-risk patients with oral infection during preoperative staging.

    PubMed

    Yamashiro, Keisuke; Nakano, Makoto; Sawaki, Koichi; Okazaki, Fumihiko; Hirata, Yasuhisa; Takashiba, Shogo

    2016-08-01

    It is sometimes difficult to determine during the preoperative period whether patients have oral infections; these patients need treatment to prevent oral infection-related complications from arising during medical therapies, such as cancer therapy and surgery. One of the reasons for this difficulty is that basic medical tests do not identify oral infections, including periodontitis and periapical periodontitis. In this report, we investigated the potential of positron emission tomography/computerized tomography (PET/CT) as a diagnostic tool in these patients. We evaluated eight patients during the preoperative period. All patients underwent PET/CT scanning and were identified as having the signs of oral infection, as evidenced by (18)F-fludeoxyglucose (FDG) localization in the oral regions. Periodontal examination and orthopantomogram evaluation showed severe infection or bone resorption in the oral regions. (18)F-FDG was localized in oral lesions, such as severe periodontitis, apical periodontitis, and pericoronitis of the third molar. The densities of (18)F-FDG were proportional to the degree of inflammation. PET/CT is a potential diagnostic tool for oral infections. It may be particularly useful in patients during preoperative staging, as they frequently undergo scanning at this time, and those identified as having oral infections at this time require treatment before cancer therapy or surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Three-Dimensional Planning in Maxillofacial Fracture Surgery: Computer-Aided Design/Computer-Aided Manufacture Surgical Splints by Integrating Cone Beam Computerized Tomography Images Into Multislice Computerized Tomography Images.

    PubMed

    Ren, Jiayin; Zhou, Zhongwei; Li, Peng; Tang, Wei; Guo, Jixiang; Wang, Hu; Tian, Weidong

    2016-09-01

    This study aimed to evaluate an innovative workflow for maxillofacial fracture surgery planning and surgical splint designing. The maxillofacial multislice computerized tomography (MSCT) data and dental cone beam computerized tomography (CBCT) data both were obtained from 40 normal adults and 58 adults who suffered fractures. The each part of the CBCT dentition image was registered into MSCT image by the use of the iterative closest point algorithm. Volume evaluation of the virtual splints that were designed by the registered MSCT images and MSCT images of the same object was performed. Eighteen patients (group 1) were operated without any splint. Twenty-one (group 2) and 19 patients (group 3) used the splints designed according to the MSCT images and registered MSCT images, respectively. The authors' results showed that the mean errors between the 2 models ranged from 0.53 to 0.92 mm and the RMS errors ranged from 0.38 to 0.69 mm in fracture patients. The mean errors between the 2 models ranged from 0.47 to 0.85 mm and the RMS errors ranged from 0.33 to 0.71 mm in normal adults. 72.22% patients in group 1 recovered occlusion. 85.71% patients in group 2, and 94.73% patients in group 3 reconstructed occlusion. There was a statistically significant difference between the MSCT images based splints' volume and the registered MSCT splints' volume in patients (P <0.05). The MSCT images based splints' volume was statistically significantly distinct from the registered MSCT splints' volume in normal adults (P <0.05). There was a statistically significant difference between the MSCT images based splints' volume and the registered MSCT splints' volume in patients and normal adults (P <0.05). The occlusion recovery rate of group 3 was better than that of group 1 and group 2. The way of integrating CBCT images into MSCT images for splints designing was feasible. The volume of the splints designed by MSCT images tended to be smaller than the splints designed by

  2. Computerized X-ray reconstruction tomography in stereometric analysis of cardiovascular dynamics

    NASA Technical Reports Server (NTRS)

    Robb, R. A.; Harris, L. D.; Ritman, E. L.

    1977-01-01

    A computerized technique is proposed for obtaining cross-sectional images of the dynamic spatial distribution of X-ray attenuation covering the entire anatomic extent of the thorax and its contents in living dogs with a resolution of 1 mm and at time intervals of 1/60 sec. Use is made of an X-ray imaging chain which is a new high-performance video-fluoroscopic system, unique in its design and construction and called SSDSR for single source dynamic spatial reconstructor. This dynamic spatial reconstruction system is shown to provide the temporally and spatially coherent multiple cross sections required to obtain the full three-dimensional anatomic and simultaneous hemodynamic information necessary for detailed quantitative analyses of regional cardiopulmonary and vascular functions in both basic investigations of animals and clinical diagnostic applications to patients. Numerous photographs supplement the text.

  3. Computerized X-ray reconstruction tomography in stereometric analysis of cardiovascular dynamics

    NASA Technical Reports Server (NTRS)

    Robb, R. A.; Harris, L. D.; Ritman, E. L.

    1977-01-01

    A computerized technique is proposed for obtaining cross-sectional images of the dynamic spatial distribution of X-ray attenuation covering the entire anatomic extent of the thorax and its contents in living dogs with a resolution of 1 mm and at time intervals of 1/60 sec. Use is made of an X-ray imaging chain which is a new high-performance video-fluoroscopic system, unique in its design and construction and called SSDSR for single source dynamic spatial reconstructor. This dynamic spatial reconstruction system is shown to provide the temporally and spatially coherent multiple cross sections required to obtain the full three-dimensional anatomic and simultaneous hemodynamic information necessary for detailed quantitative analyses of regional cardiopulmonary and vascular functions in both basic investigations of animals and clinical diagnostic applications to patients. Numerous photographs supplement the text.

  4. [A quantitative evaluation of brain computerized tomography in children using color image analyzer].

    PubMed

    Yamatani, M; Naganuma, Y; Hongoh, K; Murakami, M; Konishi, T; Okada, T

    1989-11-01

    We attempted the quantitative analysis of brain computerized tomographic scans in children using Color Image Analyzer. A consecutive series of 167 computerized tomographic scans were reviewed. Areas of subarachnoid spaces, cavums, ventricles and cerebellums were measured on three slices: A slice is at the level of head of caudate nucleus, anterior horn of lateral ventricle and third ventricle. B slice is at the level of body of lateral ventricle. C slice is at the level of sella turcica and pons. We investigated these values compared with Evans ratio, Cella Media Index, cerebellar atrophy score and visually evaluations. Serial brain CT scans of eight patient with infantile spasms were also evaluated for the assessment of the brain shrinkage after ACTH therapy. 1) The ratios of the subarachnoid space/the intracranial area on A and B slices (SAS A%, SAS B%) were significantly higher in the patients of severe brain atrophy. 2) There were linear relationship between Evans ratio and SAS A% (r = 0.405, p less than 0.001), Cella Media Index and the ratio of the lateral ventricles/the intracranial areas on B slice (r = -0.501, p less than 0.001), and the cerebellar atrophy score by Une and SAS C% (r = 0.369, p less than 0.001). 3) In the normal patients, the values of SAS A% and SAS B% were much greater in less than 1.5 years old children. These results suggest that the trend of CT findings related to age may reflect physiological changes of the space between the skull and the brain with age. 4) Brain shrinkage after ACTH therapy was more pronounced in the subarachnoid space than the ventricle.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. [Contrast media extravasation in upper abdominal injuries: detection with spiral computerized tomography].

    PubMed

    Catalano, O; Lobianco, R; Esposito, M; Sandomenico, F; Siani, A

    1999-03-01

    The possibility of detecting contrast agent extravasation (i.e., active hemorrhage) with dynamic conventional Computed Tomography (CT) in patients with abdominal trauma has already been reported in small series. We report our experience in the demonstration of contrast material extravasation using helical CT; we also investigate the diagnostic and clinical value of this finding. January 1997 to July 1998, we examined 41 consecutive patients with upper abdominal trauma. Twelve patients (29%) had contrast material extravasation. The examinations were performed with a helical unit and volumetric acquisitions (thickness 8-10 mm, pitch 1, reconstruction interval 5-8 mm). The intravenous contrast medium (350 mgI/mL, 130-140 mL) was administered with rapid infusion (2-2.5 mL/s, 40-50 s acquisition delay from bolus starting) and using a power injector. We reviewed the CT studies and clinical records of these 12 patients. Contrast agent extravasation was considered present when this finding, not recognizable on plain scans, showed equal attenuation to or higher attenuation than the vessels within the same level. Moreover we assessed leak site, CT appearance, the direct visualization of the involved vessel, the evidence of other abdominal or extra-abdominal injuries, the CT signs of hypovolemic shock, clinical and surgical data. For comparison, we finally evaluated 50 examinations performed with a conventional CT scanner in subjects with abdominal trauma. Active hemorrhage involved the abdominal wall in 1 case (intercostal artery), the solid organs in 4 (splenic in 2, hepatic in 1, of the middle hepatic vein in 1), the peritoneal cavity in 3 (splenic, midcolic, and gastroduodenal artery in 1 each), the retroperitoneum in 4 (renal pedicle in 2, renal parenchyma in 1, lumbar artery in 1). In all cases the site of contrast extravasation corresponded at surgery to the site of active bleeding. The pattern was localized in 10 cases and diffuse in 2. The involved vessel could be

  6. Use of computerized tomography for diagnosis and follow-up after endodontic surgery: clinical case report with 8 years of follow-up.

    PubMed

    Tanomaru-Filho, Mario; Lima, Regina K P; Nakazone, Paula A; Tanomaru, Juliane M G

    2010-04-01

    Computerized tomography (CT) is a valuable tool for diagnosis and planning in conventional and surgical endodontic therapy. This case report describes the use of CT in the diagnosis of a periapical lesion undetected by periapical radiography in the mandibular molar area. The CT also showed a possible mesial root perforation associated with the lesion. Following CT, surgical planning, periradicular curettage, and sealing of the root perforation were performed. Eight years after surgery, cone beam CT revealed periapical bone repair. Computerized tomography can be an important resource for diagnosis and planning in conventional and surgical endodontic therapy, as well as for evaluation of post-treatment bone repair. Copyright 2010 Mosby, Inc. All rights reserved.

  7. Computerized tomography versus perfusion lung scanning in canine radiation lung injury

    SciTech Connect

    Ahmed, I.H.; Logus, J.W.; El-Khatib, E.; Battista, J.J.; Ferri, H.; Lentle, B.C.; Man, G.C.; Man, S.F. )

    1990-03-01

    Computerized tomographic (CT) measurements of lung density were obtained before and serially after thoracic irradiation in dogs to detect the alterations caused by radiation therapy. Fourteen mongrel dogs were given either 2000 cGy (Group A, 10 dogs, right lower zone irradiation), 1000 cGy (Group B, 2 dogs, right lower zone irradiation), or 500 cGy (Group C, 2 dogs, right lung irradiation) in one fraction. Once before and bi-weekly after irradiation, the anesthetized dogs had thoracic CT scans. CT numbers for the irradiated area were compared to their preirradiation control values. Macro-aggregated albumin (MAA) perfusion lung scans were also obtained before and at weekly intervals after irradiation and were evaluated visually and quantitatively for abnormalities. When both these tests were abnormal, or at the end of the scheduled study, the dogs were sacrificed to confirm radiation lung injury histologically. Our results showed that CT numbers (as a measure of tissue density) were higher with higher doses of radiation. Among all the techniques used, only the quantitative assessment of macro-aggregated albumin perfusion scan detected abnormalities in all the dogs given 2000 cGy. Their abnormalities correlated well with the presence of radiation lung damage histologically, however, the applicability of these methods in the detection of early injury has to be further evaluated.

  8. Real-time, multiplanar computerized tomography: a new diagnostic modality used in the detection and endoscopic removal of a distal ureteral fibroepithelial polyp and adjacent calculus.

    PubMed

    Oesterling, J E; Liu, H Y; Fishman, E K

    1989-12-01

    Ureteral fibroepithelial polyps are rare benign mesodermal tumors that occur predominantly in the upper ureter. We report on a patient with a fibroepithelial polyp in the distal ureter that resulted in entrapment of a calculus and partial obstruction of the collecting system. Preoperatively, diagnosis by standard radiographic methods, such as excretory urogram, retrograde pyelogram and conventional computerized tomography with and without contrast enhancement, was not possible because of the close proximity of the fibroepithelial polyp, the ureteral calculus and calcifications in the adjacent internal iliac artery. The new diagnostic modality of real-time, multiplanar computerized tomography imaging using the Sun/Pixar computer system and the 2D/3D Orthotool software was used to make the correct preoperative assessment. Subsequently, the patient underwent ureteroscopic resection of the polyp and extraction of the calculus. A year later she was free of symptoms and there was no evidence of regrowth of the polyp. To our knowledge this is the first report to describe the use of real-time, multiplanar computerized tomography imaging as an effective diagnostic modality in the genitourinary tract. In addition, this is the first ureteral fibroepithelial polyp reported in the literature to be associated with a ureteral calculus and to be excised endoscopically with no recurrence on long-term followup.

  9. Assessment of the severity of acute pancreatitis by contrast-enhanced computerized tomography in 350 patients.

    PubMed

    Mir, Mohd Altaf; Bali, Biant Singh; Mir, Riyaz Ahmad; Wani, Hamza

    2013-03-01

    This prospective study has been conducted with the aim to assess the severity of acute pancreatitis. The study included 350 consecutive patients with acute pancreatitis admitted over a period of five years. All these patients were subjected to detailed history and clinical examination and investigations to ascertain the diagnosis. The severity was assessed by contrast - enhanced computed tomography (CT). Data collected were tabulated and subjected to appropriate statistical analysis. On the basis of the CT Severity Index (CTSI), the severity of acute pancreatic was classified into Group A (mild), Group B (moderate), or Group C (severe). Group C patients had the most complications (in 77 [91.67%] patients), and Group A patients had the least (in 7 [6.25%] patients). Mortality was found to be highest among Group C (14 [16.67%] patients), indicating the severe nature of disease in these patients, while no mortality was noted in Group A patients. The mean duration of hospital stay of patients in Group A was 9.25 days, Group B 12.0 days and Group C 24.58 days. The use of contrast-enhanced computed tomography as a routine investigation in patients to predict a severe attack of acute pancreatitis early in the course of the disease decreases overall mortality and burden of disease.

  10. Effective radiation dose of ProMax 3D cone-beam computerized tomography scanner with different dental protocols.

    PubMed

    Qu, Xing-min; Li, Gang; Ludlow, John B; Zhang, Zu-yan; Ma, Xu-chen

    2010-12-01

    The aim of this study was to compare effective doses resulting from different scan protocols for cone-beam computerized tomography (CBCT) using International Commission on Radiological Protection (ICRP) 1990 and 2007 calculations of dose. Average tissue-absorbed dose, equivalent dose, and effective dose for a ProMax 3D CBCT with different dental protocols were calculated using thermoluminescent dosimeter chips in a human equivalent phantom. Effective doses were derived using ICRP 1990 and the superseding 2007 recommendations. Effective doses (ICRP 2007) for default patient sizes from small to large ranged from 102 to 298 μSv. The coefficient of determination (R(2)) between tube current and effective dose (ICRP 2007) was 0.90. When scanning with lower resolution settings, the effective doses were reduced significantly (P < .05). ProMax 3D can provide a wide range of radiation dose levels. Reduction in radiation dose can be achieved when using lower settings of exposure parameters. Copyright © 2010 Mosby, Inc. All rights reserved.

  11. A novel three-dimensional image reconstruction method for near-field coded aperture single photon emission computerized tomography

    PubMed Central

    Mu, Zhiping; Hong, Baoming; Li, Shimin; Liu, Yi-Hwa

    2009-01-01

    Coded aperture imaging for two-dimensional (2D) planar objects has been investigated extensively in the past, whereas little success has been achieved in imaging 3D objects using this technique. In this article, the authors present a novel method of 3D single photon emission computerized tomography (SPECT) reconstruction for near-field coded aperture imaging. Multiangular coded aperture projections are acquired and a stack of 2D images is reconstructed separately from each of the projections. Secondary projections are subsequently generated from the reconstructed image stacks based on the geometry of parallel-hole collimation and the variable magnification of near-field coded aperture imaging. Sinograms of cross-sectional slices of 3D objects are assembled from the secondary projections, and the ordered subset expectation and maximization algorithm is employed to reconstruct the cross-sectional image slices from the sinograms. Experiments were conducted using a customized capillary tube phantom and a micro hot rod phantom. Imaged at approximately 50 cm from the detector, hot rods in the phantom with diameters as small as 2.4 mm could be discerned in the reconstructed SPECT images. These results have demonstrated the feasibility of the authors’ 3D coded aperture image reconstruction algorithm for SPECT, representing an important step in their effort to develop a high sensitivity and high resolution SPECT imaging system. PMID:19544769

  12. Discrepancies between leg-to-leg bioelectrical Impedance analysis and computerized tomography in abdominal visceral fat measurement.

    PubMed

    Lu, Hsueh-Kuan; Chen, Yu-Yawn; Yeh, Chinagwen; Chuang, Chih-Lin; Chiang, Li-Ming; Lai, Chung-Liang; Casebolt, Kevin M; Huang, Ai-Chun; Lin, Wen-Long; Hsieh, Kuen-Chang

    2017-08-22

    The aim of this study was to evaluate leg-to-leg bioelectrical impedance analysis (LBIA) using a four-contact electrode system for measuring abdominal visceral fat area (VFA). The present study recruited 381 (240 male and 141 female) Chinese participants to compare VFA measurements estimated by a standing LBIA system (VFALBIA) with computerized tomography (CT) scanned at the L4-L5 vertebrae (VFACT). The total mean body mass index (BMI) was 24.7 ± 4.2 kg/m(2). Correlation analysis, regression analysis, Bland-Altman plot, and paired sample t-tests were used to analyze the accuracy of the VFALBIA. For the total subjects, the regression line was VFALBIA = 0.698 VFACT + 29.521, (correlation coefficient (r) = 0.789, standard estimate of error (SEE) = 24.470 cm(2), p < 0.001), Lin's correlation coefficient (CCC) was 0.785; and the limit of agreement (LOA; mean difference ±2 standard deviation) ranged from -43.950 to 67.951 cm(2), LOA% (given as a percentage of mean value measured by the CT) was 48.2%. VFALBIA and VFACT showed significant difference (p < 0.001). Collectively, the current study indicates that LBIA has limited potential to accurately estimate visceral fat in a clinical setting.

  13. Differentiation of ureteral stones and phleboliths using Hounsfield units on computerized tomography: a new method without observer bias.

    PubMed

    Tanidir, Yiloren; Sahan, Ahmet; Asutay, Mehmet Kazim; Sener, Tarik Emre; Talibzade, Farhad; Garayev, Asgar; Tinay, Ilker; Sekerci, Cagri Akin; Simsek, Ferruh

    2017-06-01

    To differentiate ureteral stones and phleboliths by measuring density [as Hounsfield unit (HU)] and volume (as mm(3)) of the opacities in the bony pelvis on unenhanced computerized tomography (U-CT). A total of 52 patients, who underwent semirigid ureteroscopy and laser lithotripsy for distal ureteral stone and had isochoronous phleboliths in U-CT, were included. Images were reviewed for density and volume of the opacities. Data were compared, and a cut-off value was defined with receiver operating characteristics curve analysis to differentiate the nature of the opacity. Using the cut-off values of 171 mm³ for volume (sensitivity 75 %, specificity 100 %) and 643 HU for density (sensitivity 75 %, specificity 93 %), differentiation between stone and phlebolith was achieved. Differentiation of pelvic opacities needs meticulous observation with certain signs on U-CT. On the other hand, our study offers a new method, with certain cut-off values, such as 643 HU and 171 mm(3), which can be used to precisely predict the actual nature of opacities of interest.

  14. Cone beam computerized tomography: basics for digital planning in oral surgery and implantology.

    PubMed

    Rugani, P; Kirnbauer, B; Arnetzl, G V; Jakse, N

    2009-01-01

    For the diagnosis of bone pathology, planning of complex implant-supported prosthetic restorations, and guaranteeing oral surgery that is as safe and free of complications as possible, a three-dimensional radiological display is frequently indicated. Cone beam computed tomography (CBCT), which can cover a large part of the indications of the dental and oral surgical spectrum, represents an alternative to computed tomography. Moreover, the method offers the advantage that it can also be used in the dental practice, taking the existing radiation protection regulations into account. This guarantees optimum patient and user friendliness, because referral to a specialized CT facility is thus no longer necessary in most cases. In the first 12 months of the trials of the Planmeca Promax 3D at the Department of Dental Surgery and Radiology of the University Clinic for Oral and Maxillofacial Medicine in Graz, the overwhelming majority of referrals for CBCT (almost 90%) was concerned with the field of oral surgery and implantology. Oral surgical questions mainly covered aspects of wisdom tooth anatomy, position of impacted canines, premolars, and mesiodents, as well as cystic lesions. Diagnoses of the maxillary sinuses and the area of tooth preservation represented further indications. Apart from diagnostic purposes, the objective of the referrals was facilitating optimum preparation for the pending operation. In the area of implantology, this was combined frequently with pre- or post-augmentative three-dimensional digital therapy planning. CBCT showed good results in the display of hard tissue structures and can be integrated without difficulty in the daily clinical routine.

  15. Signs and symptoms after temporomandibular joint washing and cannula placement assessed by cone beam computerized tomography.

    PubMed

    Kristensen, Kasper Dahl; Stoustrup, Peter; Alstergren, Per; Küseler, Annelise; Herlin, Troels; Pedersen, Thomas Klit

    2015-08-01

    Analyses of temporomandibular joint synovial fluid using the hydroxocobalamin push-pull technique are increasingly used. However, objective complications and subjective experiences from this procedure have not been described. Firstly, this study aimed to describe discomfort and potential side-effects of this method with special emphasis on symptoms related to the arthrocentesis to be used for future patient information and Ethical Committee applications. Secondly, this study aimed to evaluate the use of cone beam computed tomography (CBCT) as control of intra-capsular cannula placement. Twenty healthy, young adult volunteers were included. Extensive objective and subjective questionnaires were completed before and 14 days after the synovial fluid sampling. With the cannula inside the joints a CBCT was done to investigate if this procedure can be used to verify intra-capsular cannula position. The subjective findings: Most subjects did experience mild pain or discomfort post-operatively. In 12 of 20 subjects symptoms had resolved after 2 days and no subjects had symptoms for more than a week. The longer lasting symptoms were mainly transient joint sounds on mandibular movement. Objective findings: 14 days after the sampling mandibular protrusion had improved 1 mm, but all other objective measures were equal compared to baseline. CBCT showed a large variation in cannula position and no conclusions could be drawn from this. The hydroxocobalamin push-pull synovial fluid sampling may cause minor, transient symptoms. CBCT does not seem to provide any clinical benefits concerning the correct cannula position in relation to the upper joint compartment and disc.

  16. [Densitometry analysis with quantitative computerized tomography in 530 subjects from Southern Italy].

    PubMed

    Addesso, A M; Cinque, T; Del Vecchio, W; Salvi, V; Schillirò, F

    1996-10-01

    Quantitative measure of bone mineral content (BMC) loss is an important diagnostic indicator for determining the risk of fracture and in following the course of patients undergoing therapy for osteoporosis. Several techniques have been used to evaluate this parameter. Quantitative Computed Tomography (QCT) is the most precise and accurate method allowing selective measurement of trabecular compartment of the vertebrae. Age, sex, ethnic heritage and geographic factors influence BMC variability. The aim of this study is to describe the normal cross-section pattern of age-related spinal bone loss in a Southern Italy population (530 healthy subjects: 450 women, 80 men) and to provide a local data-base for better interpretation of the BMC values. The BMC of lumbar spine was measured by single energy QCT, using a reference phantom with five tubes containing known amounts of CaCO3, placed approximately at the vertebral bodies L2-L4. Results indicate an age-related bone loss with the lowest values at 55-70 years, particularly in women, while no major further decrease was observed in subjects over 65 years. Normal linear BMC decrease rate can be derived from this data.

  17. [Evidence of otospongiosis obtained by computerized tomography. Does it compromise the post-stapedectomy auditory gain?].

    PubMed

    Montaño Velázquez, B B; Bello Mora, A; Zepeda López, E G; Ramírez Martínez, J; Hernández Goribar, M; Jáuregui-Renaud, K

    2002-01-01

    To study the influence of tomographic otospongiosis/otosclerosis on the audiometric gain after stapedectomy, we evaluated 34 patients (mean age 39.9 years, S.D. 9.8) with otosclerosis and mixed hearing loss. We performed Computed Tomography (CT) with densitometry before stapedectomy and audiometry before and 4 weeks after the surgery. CT results were classified as compatible or not for otospongiosis (< 1000 UH) or for otosclerosis (> 2000 UH). According to the affected turns of the cochlea, the studies were classified in 3 groups. In 43% of the patients the CT showed otospongiosis. After stapedectomy, air conduction thresholds of the low (125-500 Hz), middle (500-2000 Hz) and high frequency bands (2000-8000 Hz) and for the air/bone gap were similar for the ears with or without otospongiosis (p > 0.05, ANOVA). However, patients with otospongiosis in all the cochlea showed the lowest audiometric gain for the high frequency band (p < 0.05 ANOVA). Evidence of otospongiosis evaluated just by CT has a low impact on the audiometric outcome after stapedectomy.

  18. Computerized Tomography-Guided Stereotactic Biopsy of Intracranial Lesions: Report of 500 Consecutive Cases.

    PubMed

    Can, Songul Meltem; Turkmenoglu, Osman Nuri; Tanik, Canan; Uysal, Ender; Ozoner, Baris; Kaldirimoglu, Saime Ayca; Musluman, Ahmet Murat; Yilmaz, Adem; Cavusoglu, Halit; Bayindir, Cicek; Aydin, Yunus

    2017-01-01

    Computed tomography (CT)-guided stereotactic brain biopsy has been performed in our clinic since March 1998. In this prospective study, we examined the patient data undergoing stereotactic biopsy and the results of biopsies in 500 consecutive patients. Between the dates of March 1998 and January 2015, CT-guided stereotactic biopsies were performed by using the Leksell stereotactic frame system (Elekta Instruments EU, Sweden) in 500 patients. A total of 512 procedures were performed in patients consisting of 184 females (36.8%) and 316 males (63.2%), ages ranging from 3 to 81 years (mean 50.40±16.67). Conclusive histopathological diagnosis was not achieved in 17(3.3%) of 512 procedures. Of the others, 173 (33.8%) were high-grade gliomas, 103 (20.1%) were low-grade gliomas, 36 (7%) were malignant lymphomas, 34 (6.6%) were other types of brain tumors, 82 (16%) were metastasis and 67 (13.1%) were non-tumoral lesions. Complications were occurred in ten cases: 3 tumoral bleedings, 2 hypertensive cerebral hematomas, 2 peroperative convulsions, 1 epidural hematoma, 1 myocardial infarction and 1 brain edema. The patients who developed myocardial infarction and hypertensive thalamic hematoma died. The mortality was 0.4% and morbidity was 1.6% in 512 procedures. CT-guided stereotactic biopsy is a reliable and a safe procedure in cases with intracranial lesions when histopathological diagnosis is required for the appropriate treatment.

  19. [Digital angiography and lipiodol computerized tomography in the anatomopathological framework of hepatocarcinoma].

    PubMed

    Pozzi-Mucelli, R; Pozzi-Mucelli, R; Pagnan, L; Dalla Palma, L

    1994-12-01

    The introduction of therapies other than conventional surgery of hepatocellular carcinoma (HCC) requires an accurate pathologic classification, which is important because it is well known that HCC may have multicentric growth. The Liver Cancer Study Group of Japan has proposed a classification dividing HCCs into three macroscopic forms from the pathologic point of view: nodular, massive and infiltrating HCCs. The nodular type is subdivided into four types: single nodular type, single nodular type with surrounding proliferation, multinodular fused type and multinodular type. Forty-six HCC patients were examined with Lipiodol Computed Tomography (LCT) to investigate the agreement between pathologic and imaging findings. LCT proved to be in close agreement with pathologic findings. Sixteen cases were classified as type I (single nodular type), 8 as type II (single nodular type with limited foci), 1 as type III (multinodular fused type), 18 as type IV (multiple nodular type with diffuse foci) and 3 cases as type V (massive form). No cases of infiltrative forms were observed in our series. Based on LCT findings, the capabilities of digital subtraction angiography (DSA) were studied in the pathologic classification of HCCs. DSA exhibited some limitations in the pathologic classification of HCCs in 5 of 16 patients with type I lesions. In these cases DSA suggested false-positive diagnoses because of regenerative nodules in cirrhotic liver in 3 cases and of daughter nodules (not confirmed at LCT) in 2 cases. In 7 of 8 patients with type II HCCs, DSA failed to show the daughter nodules surrounding the main nodule. In the 18 patients with multiple distant nodules (type IV), DSA was less sensitive in defining nodule number and site. In the massive form, the information obtained with LCT and DSA was comparable. In conclusion, LCT should be considered a basic examination in the study of HCC extent. Based on LCT findings, the most appropriate treatment can be selected, be it

  20. Automated assessment of renal cortical surface roughness from computerized tomography images and its association with age.

    PubMed

    Duan, Xinhui; Rule, Andrew D; Elsherbiny, Hisham; Vrtiska, Terri J; Avula, Ramesh T; Alexander, Mariam P; Lerman, Lilach O; McCollough, Cynthia H

    2014-11-01

    Nephrosclerosis occurs with aging and is characterized by increased kidney subcapsular surface irregularities at autopsy. Assessments of cortical roughness in vivo could provide an important measure of nephrosclerosis. The purpose of this study was to develop and validate an image-processing algorithm for quantifying renal cortical surface roughness in vivo and determine its association with age. Renal cortical surface roughness was measured on contrast-enhanced abdominal computed tomography (CT) images of potential living kidney donors. A roughness index was calculated based on geometric curvature of each kidney from three-dimensional images and compared to visual observation scores. Cortical roughness was compared between the oldest and youngest donors, and its interaction with cortical volume and age assessed. The developed quantitative roughness index identified significant differences in kidneys with visual surface roughness scores of 0 (minimal), 1 (mild), and 2 (moderate; P < .001) in a random sample of 200 potential kidney donors. Cortical roughness was significantly higher in the 94 oldest (64-75 years) versus 91 youngest (18-25 years) potential kidney donors (P < .001). Lower cortical volume was associated with older age but not with roughness (r = -0.03, P = .75). The association of oldest age group with roughness (odds ratio [OR] = 1.8 per standard deviation [SD] of roughness index) remained significant after adjustment for total cortex volume (OR = 2.0 per SD of roughness index). A new algorithm to measure renal cortical surface roughness from CT scans detected rougher surface in older compared to younger kidneys, independent of cortical volume loss. This novel index may allow quantitative evaluation of nephrosclerosis in vivo using contrast-enhanced CT. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

  1. Tympanic membrane boundary deformations derived from static displacements observed with computerized tomography in human and gerbil.

    PubMed

    Gea, Stefan L R; Decraemer, Willem F; Funnell, W Robert J; Funnell, Robert W J; Dirckx, Joris J J; Maier, Hannes

    2010-03-01

    The middle ear is too complex a system for its function to be fully understood with simple descriptive models. Realistic mathematical models must be used in which structural elements are represented by geometrically correct three-dimensional (3D) models with correct physical parameters and boundary conditions. In the past, the choice of boundary conditions could not be based on experimental evidence as no clear-cut data were available. We have, therefore, studied the deformation of the tympanic membrane (TM) at its boundaries using X-ray microscopic computed tomography in human and gerbil while static pressure was applied to the ear canal. The 3D models of the TM and its bony attachments were carefully made and used to measure the deformation of the TM with focus on the periphery and the manubrium attachment. For the pars flaccida of the gerbil, the boundary condition can, for the most part, be described as simply supported. For the human pars flaccida, the situation is more complicated: superiorly, the membrane contacts the underlying bone more and more when pushed further inward, and it gradually detaches from the wall when sucked outward. In gerbil, the attachment of the TM to the manubrium can be described as simply supported. In human, the manubrium is attached underneath the TM via the plica mallearis and the contact of the TM with the bone is indirect. For both human and gerbil, a simple boundary condition for the peripheral edge of the pars tensa is not appropriate due to the intricate structure at the edge: the TM thickens rapidly before continuing into the annulus fibrosis which finally makes contact with the bone.

  2. Interfraction Prostate Rotation Determined from In-Room Computerized Tomography Images

    SciTech Connect

    Owen, Rebecca; Kron, Tomas; Foroudi, Farshad; Milner, Alvin; Cox, Jennifer; Duchesne, Gillian

    2011-07-01

    Fiducial markers (FMs) are commonly used as a correction technique for interfraction translations of the prostate. The aim of this investigation was to determine the magnitude of prostate rotations using 2 methods: FM coordinates and the anatomical border of the prostate and rectum. Daily computed tomography (CT) scans (n = 346) of 10 prostate cancer patients with 3 implanted FMs were acquired using the CT on rails. FM coordinates were used to determine rotation in the sagittal, transverse, and coronal planes, and CT contours of the prostate and rectum were used to determine rotation along the sagittal plane. An adaptive technique based on a subset of images (n = 6; planning and first 5 treatment CTs) to reduce systematic rotation errors in the sagittal plane was tested. The standard deviation (SD) of systematic rotation from FM coordinates was 7.6{sup o}, 7.7{sup o}, and 5.0{sup o} in the sagittal, transverse and coronal planes. The corresponding SD of random error was 10.2{sup o}, 15.8{sup o}, and 6.5{sup o}. Errors in the sagittal plane, determined from prostate and rectal contours, were 10.1{sup o} (systematic) and 7.7{sup o} (random). These results did not correlate with rotation computed from FM coordinates (r = -0.017; p = 0.753, n = 337). The systematic error could be reduced by 43% to 5.6{sup o} when the mean prostate position was estimated from 6 CT scans. Prostate rotation is a significant source of error that appears to be more accurately determined using the anatomical border of the prostate and rectum rather than FMs, thus highlighting the utility of CT image guidance.

  3. Fragility of Brushite Stones in Shock Wave Lithotripsy: Absence of Correlation with Computerized Tomography Visible Structure

    PubMed Central

    Williams, James C.; Hameed, Tariq; Jackson, Molly E.; Aftab, Syed; Gambaro, Alessia; Pishchalnikov, Yuri A.; Lingeman, James E.; McAteer, James A.

    2012-01-01

    Purpose Brushite stones were imaged in vitro and then broken with shock wave (SW) lithotripsy (SWL) to assess whether stone fragility correlates with internal stone structure visible by helical computed tomography (helical CT). Materials and Methods 52 brushite stones were scanned by micro CT, weighed, hydrated, and placed within a radiological phantom. The stones were scanned using a Philips Brilliance iCT 256 system, and the images evaluated for visibility of internal structural features. The stones were then treated by SWL in vitro, and the number of SWs needed to break each stone to completion was recorded. Results The number of SWs to break each stone, normalized to stone weight, did not differ by Hounsfield unit value (P=0.84), or CT-visible structure that could be identified consistently by all observers (P =0.053). Fragility of stones was highly correlated with stone density and with brushite content (both P <0.001), with stones of nearly pure brushite requiring the most SWs to break. When all observations of CT-visible structure were used in analysis by logistic fit, CT-visible structure predicted increased stone fragility with an overall area under the receiver operating characteristic (ROC) curve of 0.64. Conclusions SWL fragility of brushite stones did not correlate with internal structure discernable using helical CT. However, fragility did correlate with stone density and increasing brushite mineral content, which is consistent with clinical experience with brushite stone patients. Thus, current technology in diagnostic CT does not provide a means to predict when brushite stones will break well using SW lithotripsy. PMID:22819106

  4. Laparoscopic vs computerized tomography-guided radiofrequency ablation for large hepatic hemangiomas abutting the diaphragm

    PubMed Central

    Gao, Jun; Kong, Jian; Ding, Xue-Mei; Ke, Shan; Niu, Hai-Gang; Xin, Zong-Hai; Ning, Chun-Min; Guo, Shi-Gang; Li, Xiao-Long; Zhang, Long; Dong, Yong-Hong; Sun, Wen-Bing

    2015-01-01

    AIM: To compare safety and therapeutic efficacy of laparoscopic radiofrequency (RF) ablation vs computed tomography (CT)-guided RF ablation for large hepatic hemangiomas abutting the diaphragm. METHODS: We retrospectively reviewed our sequential experience of treating 51 large hepatic hemangiomas abutting the diaphragm in 51 patients by CT-guided or laparoscopic RF ablation due to either the presence of symptoms and/or the enlargement of hemangioma. Altogether, 24 hemangiomas were ablated via a CT-guided percutaneous approach (CT-guided ablation group), and 27 hemangiomas were treated via a laparoscopic approach (laparoscopic ablation group). RESULTS: The mean diameter of the 51 hemangiomas was 9.6 ± 1.8 cm (range, 6.0-12.0 cm). There was no difference in the diameter of hemangiomas between the two groups (P > 0.05). RF ablation was performed successfully in all patients. There was no difference in ablation times between groups (P > 0.05). There were 23 thoracic complications in 17 patients: 15 (62.5%, 15/24) in the CT-guided ablation group and 2 (7.4%, 2/27) in the laparoscopic ablation group (P < 0.05). According to the Dindo-Clavien classification, two complications (pleural effusion and diaphragmatic rupture grade III) were major in two patients. All others were minor (grade I). Both major complications occurred in the CT-guided ablation group. The minor complications were treated successfully with conservative measures, and the two major complications underwent treatment by chest tube drainage and thoracoscopic surgery, respectively. Complete ablation was achieved in 91.7% (22/24) and 96.3% (26/27) in the CT-guided and the laparoscopic ablation groups, respectively (P > 0.05). CONCLUSION: Laparoscopic RF ablation therapy should be used as the first-line treatment option for large hepatic hemangiomas abutting the diaphragm. It avoids thermal injury to the diaphragm and reduces thoracic complications. PMID:26019459

  5. Computerized comparison of the protein compositions of Erysipelothrix rhusiopathiae and Erysipelothrix tonsillarum strains.

    PubMed

    Bernáth, S; Német, L; Tóth, K; Morovján, G

    2001-02-01

    Protein profiles of six Erysipelothrix rhusiopathiae strains, five Erysipelothrix tonsillarum strains and three Erysipelothrix strains of uncertain taxonomic position were studied by sodium dodecyl sulphate-polyactylamide gel electrophoresis (SDS-PAGE). In a computerized comparison of the protein patterns of the strains, the level of similarity between the strains was determined. The SDS-PAGE protein bands were divided into 14 groups based on molecular weight. The relative distribution of proteins within these groups was used to characterize the strains. These distribution patterns were analysed by computing Pearson's correlation coefficient between strains, and by cluster analysis based on Euclidean distances and the unweighted pair-group method of arithmetic averages (UPGMA). The geometric mean of the similarities calculated by Pearson's correlation coefficient was 0.980 +/- 0.018 between the E. rhusiopathiae strains and 0.979 +/- 0.013 for E. tonsillarum strains. The value was 0.932 +/- 0.036 between the strains belonging to different species. However, a threshold value applicable for identification of a given strain to a species could not be established. Of the three strains of uncertain taxonomic position, the strains designated Rotzunge and Iszap 4 had a protein composition more similar to that of E. tonsillarum than to that of the E. rhusiopathiae type strain. The strain designated Pécs 56, which may be a member of a new species according to literature data, gave inconsistent results by the two methods used. The computerized evaluation method developed here is suitable for the comparison of the protein composition of the strains and for the construction of the protein similarity tree by cluster analysis.

  6. Inter-rater reliability of modified Alberta Stroke program early computerized tomography score in patients with brain infarction

    PubMed Central

    Ghandehari, Kavian; Rezvani, Mohammad Reza; Shakeri, Mohammad Taghi; Mohammadifard, Mahdi; Ehsanbakhsh, Alireza; Mohammadifard, Mahyar; Mirgholami, Alireza; Boostani, Reza; Ghandehari, Kosar; Izadi-Mood, Zahra

    2011-01-01

    BACKGROUND: The Alberta Stroke Program Early Computerized Tomography Score (ASPECTS) was used to detect significant early ischemic changes on brain CT of acute stroke patients. We designed the modified ASPECTS and compared it to the above system based on the inter-rater reliability. METHODS: A cross-sectional validation study was conducted based on the inter-rater reliability. The CT images were chosen from the stroke data bank of Ghaem hospital, Mashhad in 2010. The inclusion criteria were the presence of middle cerebral artery territory infarction and performance of CT within 6 hours after stroke onset. Axial CT scans were performed on a third-generation CT scanner (Siemens, ARTX, Germany). Section thickness above posterior fossa was 10 mm (130 kV, 150 mAs). Films were made at window level of 35 HU. The brain CTs were scored by four independent radiologists based on the ASPECTS and modified ASPECTS. The readers were blind to clinical information except symptom side. Cochrane Q and Kappa tests served for statistical analysis. RESULTS: 24 CT scans were available and of sufficient quality. Difference in distribution of dichotomized ≤7 and >7 ASPECT scores between four raters was significant (Q=13.071, df=3, p=0.04). Distribution of dichotomized <6 and ≥6 scores based on modified ASPECT system between 4 raters was not significantly different (Q=6.349, df=3, p=0.096). CONCLUSIONS: Modified ASPECT method is more reliable than ASPECTS in detecting major early ischemic changes in stroke patients candidated to tPA thrombolysis. PMID:22973327

  7. Effect of central obesity on prostate specific antigen measured by computerized tomography: related markers and prostate volume.

    PubMed

    Park, Seung-Guk; Choi, Ho-Chun; Cho, Belong; Kwon, Young-Min; Kwon, Hyuk-Tae; Park, Jin-Ho

    2012-05-01

    We assessed the effects of central adiposity represented by visceral adipose tissue on prostate volume, prostate specific antigen, and prostate specific antigen mass and mass ratio. This cross-sectional study included 6,389 Asian men 30 to 79 years old. Prostate volume was estimated by transrectal ultrasound. Visceral and subcutaneous adipose tissue was measured by computerized tomography. Multivariate linear regression analysis was done between prostate specific antigen related variables and obesity indexes such as body mass index, waist circumference, and visceral and subcutaneous adipose tissue after adjusting for age. Body mass index, waist circumference and subcutaneous adipose tissue were inversely associated with prostate specific antigen (p for trend <0.001) but visceral adipose tissue showed no associations with prostate specific antigen (p for trend = 0.740). Waist circumference, and visceral and subcutaneous adipose tissue were positively associated with prostate specific antigen mass (p for trend = 0.014, <0.001 and 0.036, respectively). However, body mass index did not show this association (p for trend = 0.372). Body mass index, waist circumference and subcutaneous adipose tissue negatively affected the prostate specific antigen mass ratio (each p for trend <0.05) but there was no such significant correlation for visceral adipose tissue (p for trend = 0.187). When adjusted for visceral adipose tissue body mass index was not associated with prostate volume (p for trend = 0.152) but visceral adipose tissue remained positively associated with prostate volume even after adjusting for body mass index (p for trend = 0.005). Visceral adiposity is the main determining factor of the prostate volume increase and prostate specific antigen production. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  8. [A radiological study of the cervical alterations in Down syndrome. New findings on computerized tomography and three dimensional reconstructions].

    PubMed

    Cros, T; Linares, R; Castro, A; Mansilla, F

    We studied a large proportion of the population in our health district who have Down's syndrome to determine the incidence and variety of changes in the spine and to define the guidelines for preventive diagnosis advisable in relation to atlanto-axial instability, a common disorder in these patients. First phase: a plain X-ray of the cervical spine in a neutral lateral projection and in flexion in 188 patients, measuring the atlanto-odontoid distance. Second phase: computerized tomography (CT) studies and three dimensional reconstructions in 25 patients (13.3%) chosen at random. The axial cuts from the upper portion of C3 to the occiput were 3 mm in thickness with 3 mm intervals and a standard reconstruction algorithm. The incidences of atlanto-axial instability with an atlodontoid distance (3)5 mm were not comparable with the published series. There was a lower incidence (4.2%), with no difference between measurements in flexion and in the neutral lateral views. There was a greater incidence of malformations than in other reports, including a rare case of os odontoideum and also constant asymmetry of the occipital condyles (100%) in the patients of the CT series and consequently instability of the atlas (96%) and off-centered odontoides (84%). The study showed that there was deficient asymmetrical development of the occipital bone, which caused different heights of the occipital condyles and led to cervico-cranial mal-position. For study of the degree of error of position and congenital anomalies. We recommend replacing plain X-ray studies by CT with three dimensional reconstructions.

  9. Non-contrast-enhanced computerized tomography and analgesic-related kidney disease: report of the national analgesic nephropathy study.

    PubMed

    Henrich, William L; Clark, Richard L; Kelly, Judith P; Buckalew, Vardaman M; Fenves, Andrew; Finn, William F; Shapiro, Joseph I; Kimmel, Paul L; Eggers, Paul; Agodoa, Larry E; Porter, George A; Shapiro, Samuel; Toto, Robert; Anderson, Theresa; Cupples, L Adrienne; Kaufman, David W

    2006-05-01

    Previous studies suggested that the non-contrast-enhanced computerized tomography (CT) scan is a highly reliable tool for the diagnosis of analgesic-associated renal disease. However, this issue has not been addressed in the US population. A total of 221 incident patients with ESRD from different regions of the United States underwent a helical CT scan and detailed questioning about drug history. Specific renal anatomic criteria were developed to determine whether a constellation of CT findings (small indented calcified kidneys [SICK]) is linked to analgesic ingestion. For approximating use before the onset of renal disease, only analgesic ingestion at least 9 yr before starting dialysis was considered relevant. Fifteen patients met the criteria for SICK. This represented 7% of the enrolled patients and approximately 1% of the total ESRD population. There was a significant increase in the estimated risk among patients with a history of heavy aspirin ingestion (odds ratio [OR] 7.4 [95% confidence interval (CI) 1.2 to 43] for > or =1 kg lifetime; OR 8.8 [95% CI 1.2 to 66] for > or =0.3 kg/yr). Total analgesic ingestion of > or =0.3 kg/yr also was significantly associated with SICK (OR 8.2; 95% CI 1.5 to 45). These findings were accounted for largely by combination products that contained aspirin and phenacetin (used by three patients with SICK), which are no longer available. In addition, the CT finding of SICK was present only in a minority of heavy analgesic users, yielding a sensitivity of 5 to 26%. Findings of SICK are infrequent in the US ESRD population and do not occur among a sufficient proportion of heavy analgesic users to render the non-contrast-enhanced CT scan a sensitive tool to detect analgesic-associated kidney injury.

  10. Metal Artifact Reduction and Segmentation of Dental Computerized Tomography Images Using Least Square Support Vector Machine and Mean Shift Algorithm.

    PubMed

    Mortaheb, Parinaz; Rezaeian, Mehdi

    2016-01-01

    Segmentation and three-dimensional (3D) visualization of teeth in dental computerized tomography (CT) images are of dentists' requirements for both abnormalities diagnosis and the treatments such as dental implant and orthodontic planning. On the other hand, dental CT image segmentation is a difficult process because of the specific characteristics of the tooth's structure. This paper presents a method for automatic segmentation of dental CT images. We present a multi-step method, which starts with a preprocessing phase to reduce the metal artifact using the least square support vector machine. Integral intensity profile is then applied to detect each tooth's region candidates. Finally, the mean shift algorithm is used to partition the region of each tooth, and all these segmented slices are then applied for 3D visualization of teeth. Examining the performance of our proposed approach, a set of reliable assessment metrics is utilized. We applied the segmentation method on 14 cone-beam CT datasets. Functionality analysis of the proposed method demonstrated precise segmentation results on different sample slices. Accuracy analysis of the proposed method indicates that we can increase the sensitivity, specificity, precision, and accuracy of the segmentation results by 83.24%, 98.35%, 72.77%, and 97.62% and decrease the error rate by 2.34%. The experimental results show that the proposed approach performs well on different types of CT images and has better performance than all existing approaches. Moreover, segmentation results can be more accurate by using the proposed algorithm of metal artifact reduction in the preprocessing phase.

  11. Calculating the number of shock waves, expulsion time, and optimum stone parameters based on noncontrast computerized tomography characteristics.

    PubMed

    Foda, Khaled; Abdeldaeim, Hussein; Youssif, Mohamed; Assem, Akram

    2013-11-01

    To define the parameters that accompanied a successful extracorporeal shock wave lithotripsy (ESWL), namely the number of shock waves (SWs), expulsion time (ET), mean stone density (MSD), and the skin-to-stone distance (SSD). A total of 368 patients diagnosed with renal calculi using noncontrast computerized tomography had their MSD, diameter, and SSD recorded. All patients were treated using a Siemens lithotripter. ESWL success meant a stone-free status or presence of residual fragments <3 mm, ET was the time in days for the successful clearance of stone fragments. Correlation was performed between the stone characteristics, number of SWs, and ET. Two multiple regression analysis models defined the number of SWs and ET. Two receiver operating characteristic curves plotted the best MSD cutoff value and optimum SSD for a successful ESWL. Three hundred one patients were ESWL successes. A significant positive correlation was elicited between number of SWs and stone diameter, density and SSD; between ET and stone diameter and density. Multiple regressions concluded 2 equations: Number of SWs = 265.108 + 5.103 x1 + 22.39 x2 + 10.931 x3 ET (days) = -10.85 + 0.031 x1 + 2.11 x2 x1 = stone density (Hounsfield unit [HUs]), x2 = stone diameter (mm), and x3 = SSD (mm). Receiver operating characteristic curves demonstrated a cutoff value of ≤ 934 HUs with 94.4% sensitivity and 66.7% specificity and P = .0211. The SSD curve showed that a distance ≤ 99 mm was 85.7% sensitive, 87.5% specific, P <.0001. Stone disintegration is not recommended if MSD is >934 HUs and SSD >99 mm. The required number of SWs and the expected ET can be anticipated. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Computerized wheeze detection in young infants: comparison of signals from tracheal and chest wall sensors.

    PubMed

    Puder, Lia C; Wilitzki, Silke; Bührer, Christoph; Fischer, Hendrik S; Schmalisch, Gerd

    2016-12-01

    Computerized wheeze detection is an established method for objective assessment of respiratory sounds. In infants, this method has been used to detect subclinical airway obstruction and to monitor treatment effects. The optimal location for the acoustic sensors, however, is unknown. The aim of this study was to evaluate the quality of respiratory sound recordings in young infants, and to determine whether the position of the sensor affected computerized wheeze detection. Respiratory sounds were recorded over the left lateral chest wall and the trachea in 112 sleeping infants (median postmenstrual age: 49 weeks) on 129 test occasions using an automatic wheeze detection device (PulmoTrack(®)). Each recording lasted 10 min and the recordings were stored. A trained clinician retrospectively evaluated the recordings to determine sound quality and disturbances. The wheeze rates of all undisturbed tracheal and chest wall signals were compared using Bland-Altman plots. Comparison of wheeze rates measured over the trachea and the chest wall indicated strong correlation (r  ⩾  0.93, p  <  0.001), with a bias of 1% or less and limits of agreement of within 3% for the inspiratory wheeze rate and within 6% for the expiratory wheeze rate. However, sounds from the chest wall were more often affected by disturbances than sounds from the trachea (23% versus 6%, p  <  0.001). The study suggests that in young infants, a better quality of lung sound recordings can be obtained with the tracheal sensor.

  13. TEC Measurements for GPS Comparisons and Ionospheric Tomography

    DTIC Science & Technology

    1999-01-01

    TEC MEASUREMENTS FOR GPS COMPARISONS AND IONOSPHERIC TOMOGRAPHY by L Kersley, S E Pryse , N Lunt, D G Jones and IK Walker Department of Physics...1975. Kersley, L., S. E. Pryse , I. K.Walker, J. A. T. Heaton, C. N. Mitchell, M. J. Williams and C. A. Willson, Imaging of electron density troughs by...ROLE OF RADIO TOMOGRAPHY IN MONITORING THE NEAR-EARTH SPACE ENVIRONMENT Cathryn N. Mitchell \\ L. Kersley \\ S. E. Pryse \\ I. K. Walkerl and P. S

  14. [Computerized tomography guided biopsy in the diagnosis of neoplastic and inflammatory lesions of the pelvis].

    PubMed

    Rimondi, E; Busacca, M; Moio, A; Molinari, M; Nigrisoli, M; Trentani, F; Trentani, P; Tigani, D

    2001-01-01

    really negative. In 5 cases (2.6%) we have had complications represented by pain at the introduction and penetration site of the needle. The choice of the needle, the approach to the lesion and the position of the patient are conditioned by the site of the tumor, its extension, the distance skin-neoplastic disease and by the respect of the incision lines of Enneking, in order not to complicate the job of the orthopaedic surgeon spreading tumoral cells outside the chosen surgical approach. The mean time of the procedure is 30 minutes (standard deviation 10). There are no absolute contraindications to percutaneous biopsy except the suspect or the presence of an hydatideal cyst. The risks have to be compared with those correlated with alternative methods or with the more concerning risk of a missed diagnosis. Complications in the literature range from 0% to 10%, the incidence varying according to the location; pain is the most frequent complication. Altogether the most negative event, although not a true complication, is the retrieval of an inadequate sample: the only drawback of percutaneous biopsy in comparison with incisional biopsy. The accuracy rate of percutaneous biopsy varies in relation to the involved anatomical region, to the pathological process, to the experience of the user, to the amount of the retrieved tissue and to the cooperation of the patient. Our experience shows that, in selected patients, percutaneous biopsy is a virtually safe and almost painless procedure which saves the patient from a surgical procedure in regional or general anestesia as for an incisional biopsy, and allows immediate planning and scheduling of a correct therapy for primitive or secondary neoplastic lesions.

  15. Clinical comparison of pain perception rates between computerized local anesthesia and conventional syringe in pediatric patients.

    PubMed

    San Martin-Lopez, Alma Luz; Garrigos-Esparza, Luis David; Torre-Delgadillo, Gabriela; Gordillo-Moscoso, Antonio; Hernandez-Sierra, Juan Francisco; de Pozos-Guillen, Amaury Jesus

    2005-01-01

    The purpose of this study was to evaluate pain perception rates in pediatric patients by comparing computerized injection device and traditional injection procedure. In a clinical trial, by using a crossover design, sixty-four patients were randomly assigned to receive, in consecutive sessions, dental anesthetic techniques with either traditional or computerized device. Visual Analogue Scale qualification and heart rate monitoring as physiologic indicator of pain response were used for the evaluation. Results showed that traditional syringe injections were more painful than computerized injection device (p < 0.001). Results suggested that computerized injection device reduces pain perception compared to the traditional syringe during the dental anesthetic management.

  16. Post transplant urinary tract infection in Autosomal dominant polycystic kidney disease a perpetual diagnostic dilema - 18-fluorodeoxyglucose - Positron emission computerized tomography - A valuable tool.

    PubMed

    Sainaresh, Vv; Jain, Sh; Patel, Hv; Shah, Pr; Vanikar, Av; Trivedi, Hl

    2011-04-01

    Urinary tract infection (UTI) is the most common infection contracted by renal allograft recipients. In patients of autosomal dominant polycystic kidney disease (ADPKD), cyst infection presents a complex diagnostic and therapeutic challenge especially in the post transplant period. Accurate diagnosis forms the cornerstone in salvaging the graft from potentially catastrophic outcome. We describe a case of xanthogranulomatous pyelonephritis (XPN) in the native kidney in a patient of post transplant ADPKD which presented as frequently relapsing UTI with graft dysfunction where in accurate diagnosis was made possible with the aid of 18-fluorodeoxyglucose (FDG) - Positron emission computerized tomography (PET/CT).

  17. Investigating the effect of characteristic x-rays in cadmium zinc telluride detectors under breast computerized tomography operating conditions.

    PubMed

    Glick, Stephen J; Didier, Clay

    2013-10-14

    A number of research groups have been investigating the use of dedicated breast computerized tomography (CT). Preliminary results have been encouraging, suggesting an improved visualization of masses on breast CT as compared to conventional mammography. Nonetheless, there are many challenges to overcome before breast CT can become a routine clinical reality. One potential improvement over current breast CT prototypes would be the use of photon counting detectors with cadmium zinc telluride (CZT) (or CdTe) semiconductor material. These detectors can operate at room temperature and provide high detection efficiency and the capability of multi-energy imaging; however, one factor in particular that limits image quality is the emission of characteristic x-rays. In this study, the degradative effects of characteristic x-rays are examined when using a CZT detector under breast CT operating conditions. Monte Carlo simulation software was used to evaluate the effect of characteristic x-rays and the detector element size on spatial and spectral resolution for a CZT detector used under breast CT operating conditions. In particular, lower kVp spectra and thinner CZT thicknesses were studied than that typically used with CZT based conventional CT detectors. In addition, the effect of characteristic x-rays on the accuracy of material decomposition in spectral CT imaging was explored. It was observed that when imaging with 50-60 kVp spectra, the x-ray transmission through CZT was very low for all detector thicknesses studied (0.5-3.0 mm), thus retaining dose efficiency. As expected, characteristic x-ray escape from the detector element of x-ray interaction increased with decreasing detector element size, approaching a 50% escape fraction for a 100 μm size detector element. The detector point spread function was observed to have only minor degradation with detector element size greater than 200 μm and lower kV settings. Characteristic x-rays produced increasing distortion

  18. Investigating the effect of characteristic x-rays in cadmium zinc telluride detectors under breast computerized tomography operating conditions

    SciTech Connect

    Glick, Stephen J.; Didier, Clay

    2013-10-14

    A number of research groups have been investigating the use of dedicated breast computerized tomography (CT). Preliminary results have been encouraging, suggesting an improved visualization of masses on breast CT as compared to conventional mammography. Nonetheless, there are many challenges to overcome before breast CT can become a routine clinical reality. One potential improvement over current breast CT prototypes would be the use of photon counting detectors with cadmium zinc telluride (CZT) (or CdTe) semiconductor material. These detectors can operate at room temperature and provide high detection efficiency and the capability of multi-energy imaging; however, one factor in particular that limits image quality is the emission of characteristic x-rays. In this study, the degradative effects of characteristic x-rays are examined when using a CZT detector under breast CT operating conditions. Monte Carlo simulation software was used to evaluate the effect of characteristic x-rays and the detector element size on spatial and spectral resolution for a CZT detector used under breast CT operating conditions. In particular, lower kVp spectra and thinner CZT thicknesses were studied than that typically used with CZT based conventional CT detectors. In addition, the effect of characteristic x-rays on the accuracy of material decomposition in spectral CT imaging was explored. It was observed that when imaging with 50-60 kVp spectra, the x-ray transmission through CZT was very low for all detector thicknesses studied (0.5–3.0 mm), thus retaining dose efficiency. As expected, characteristic x-ray escape from the detector element of x-ray interaction increased with decreasing detector element size, approaching a 50% escape fraction for a 100 μm size detector element. The detector point spread function was observed to have only minor degradation with detector element size greater than 200 μm and lower kV settings. Characteristic x-rays produced increasing distortion in

  19. Cost-effectiveness analysis of 3-D computerized tomography colonography versus optical colonoscopy for imaging symptomatic gastroenterology patients.

    PubMed

    Gomes, Manuel; Aldridge, Robert W; Wylie, Peter; Bell, James; Epstein, Owen

    2013-04-01

    When symptomatic gastroenterology patients have an indication for colonic imaging, clinicians have a choice between optical colonoscopy (OC) and computerized tomography colonography with three-dimensional reconstruction (3-D CTC). 3-D CTC provides a minimally invasive and rapid evaluation of the entire colon, and it can be an efficient modality for diagnosing symptoms. It allows for a more targeted use of OC, which is associated with a higher risk of major adverse events and higher procedural costs. A case can be made for 3-D CTC as a primary test for colonic imaging followed if necessary by targeted therapeutic OC; however, the relative long-term costs and benefits of introducing 3-D CTC as a first-line investigation are unknown. The aim of this study was to assess the cost effectiveness of 3-D CTC versus OC for colonic imaging of symptomatic gastroenterology patients in the UK NHS. We used a Markov model to follow a cohort of 100,000 symptomatic gastroenterology patients, aged 50 years or older, and estimate the expected lifetime outcomes, life years (LYs) and quality-adjusted life years (QALYs), and costs (£, 2010-2011) associated with 3-D CTC and OC. Sensitivity analyses were performed to assess the robustness of the base-case cost-effectiveness results to variation in input parameters and methodological assumptions. 3D-CTC provided a similar number of LYs (7.737 vs 7.739) and QALYs (7.013 vs 7.018) per individual compared with OC, and it was associated with substantially lower mean costs per patient (£467 vs £583), leading to a positive incremental net benefit. After accounting for the overall uncertainty, the probability of 3-D CTC being cost effective was around 60 %, at typical willingness-to-pay values of £20,000-£30,000 per QALY gained. 3-D CTC is a cost-saving and cost-effective option for colonic imaging of symptomatic gastroenterology patients compared with OC.

  20. Investigating the effect of characteristic x-rays in cadmium zinc telluride detectors under breast computerized tomography operating conditions

    NASA Astrophysics Data System (ADS)

    Glick, Stephen J.; Didier, Clay

    2013-10-01

    A number of research groups have been investigating the use of dedicated breast computerized tomography (CT). Preliminary results have been encouraging, suggesting an improved visualization of masses on breast CT as compared to conventional mammography. Nonetheless, there are many challenges to overcome before breast CT can become a routine clinical reality. One potential improvement over current breast CT prototypes would be the use of photon counting detectors with cadmium zinc telluride (CZT) (or CdTe) semiconductor material. These detectors can operate at room temperature and provide high detection efficiency and the capability of multi-energy imaging; however, one factor in particular that limits image quality is the emission of characteristic x-rays. In this study, the degradative effects of characteristic x-rays are examined when using a CZT detector under breast CT operating conditions. Monte Carlo simulation software was used to evaluate the effect of characteristic x-rays and the detector element size on spatial and spectral resolution for a CZT detector used under breast CT operating conditions. In particular, lower kVp spectra and thinner CZT thicknesses were studied than that typically used with CZT based conventional CT detectors. In addition, the effect of characteristic x-rays on the accuracy of material decomposition in spectral CT imaging was explored. It was observed that when imaging with 50-60 kVp spectra, the x-ray transmission through CZT was very low for all detector thicknesses studied (0.5-3.0 mm), thus retaining dose efficiency. As expected, characteristic x-ray escape from the detector element of x-ray interaction increased with decreasing detector element size, approaching a 50% escape fraction for a 100 μm size detector element. The detector point spread function was observed to have only minor degradation with detector element size greater than 200 μm and lower kV settings. Characteristic x-rays produced increasing distortion in the

  1. [Aging changes of the root canal morphology in maxillary first premolars observed by cone-beam computerized tomography].

    PubMed

    Hu, R C; Cao, L L; Xie, W; Hu, Y Q; Piao, Z G

    2016-04-09

    To observe the morphological changes of root canals with aging in maxillary first premolars by using cone-beam computerized tomography(CBCT)in order to facilitate endodontic management of root canals in various aged patients. The digital CBCT data of the maxillary first premolars in 405 cases from the patients in Oral Medical Center of The First Affiliated Hospital, Jinan University from March 2011 to June 2015 were collected. The CBCT images were divided into 6 groups according to the patients' ages: groups 11-20, 21-30, 31-40, 41-50, 51-60 and >60 years-olds, respectively. Changes of morphologies of root canals with aging including such parameters as types of the root canal, incidence of double root canals in single rooted teeth, distance between both root canal orifices of double rooted canals, and morphological change of the cross section of roots. Chi-square test and liner trend test were adopted in statistical analysis in the present study. The distribution of various types of the root canals were significantly different amongst various aged groups(P<0.05). Type Ⅳ is the most common type(210/405, 51.8%), and the following groups were typeⅡ(65/405, 16.0%), typeⅠ(55/405, 13.6%)and type Ⅲ(27/405, 6.7%). Along with aging, the percentages of type Ⅰ and type Ⅲ decreased while type Ⅱ increased. However, there were no remarkable changes of type Ⅳ observed. The incidence of double rooted canals in single rooted teeth gradually increased with aging especially in 20-years-old and above groups, e.g. 51.7%(31/60)in group 11-20 years-olds and 83.0%(44/53)in group 21-30 years-olds. However, there was no significant increase observed after the age of 40. The distance between both root canal orifices of double rooted canals became shorter with aging except in groups of 40-years-olds and above. The morphologies of the cross sections in most aged groups were flat shaped(1 020/2 105, 48.5%)and oval shape(594/2 105, 28.2%). Along with aging, the percentage of

  2. Quantification of Soil Physical Properties by Using X-Ray Computerized Tomography (CT) and Standard Laboratory (STD) Methods

    SciTech Connect

    Sanchez, Maria Ambert

    2003-12-12

    The implementation of x-ray computerized tomography (CT) on agricultural soils has been used in this research to quantify soil physical properties to be compared with standard laboratory (STD) methods. The overall research objective was to more accurately quantify soil physical properties for long-term management systems. Two field studies were conducted at Iowa State University's Northeast Research and Demonstration Farm near Nashua, IA using two different soil management strategies. The first field study was conducted in 1999 using continuous corn crop rotation for soil under chisel plow with no-till treatments. The second study was conducted in 2001 and on soybean crop rotation for the same soil but under chisel plow and no-till practices with wheel track and no-wheel track compaction treatments induced by a tractor-manure wagon. In addition, saturated hydraulic (K{sub s}) conductivity and the convection-dispersion (CDE) model were also applied using long-term soil management systems only during 2001. The results obtained for the 1999 field study revealed no significant differences between treatments and laboratory methods, but significant differences were found at deeper depths of the soil column for tillage treatments. The results for standard laboratory procedure versus CT method showed significant differences at deeper depths for the chisel plow treatment and at the second lower depth for no-till treatment for both laboratory methods. The macroporosity distribution experiment showed significant differences at the two lower depths between tillage practices. Bulk density and percent porosity had significant differences at the two lower depths of the soil column. The results obtained for the 2001 field study showed no significant differences between tillage practices and compaction practices for both laboratory methods, but significant differences between tillage practices with wheel track and no-wheel compaction treatments were found along the soil profile for

  3. [Validity of modified radiological views to detect screw protrusion at the distal radius. A comparative study with computerized tomography].

    PubMed

    Mora-Pascual, F E; Aguilella-Fernández, L

    2013-01-01

    Volar fixed-angle plates (VFAP) are currently widely used for the treatment of extra-articular distal radius fractures. Using these plates has a high risk of articular and dorsal screw protrusion due to their special configuration. The aim of this study is to assess the validity of the standard X-rays, performed with the help of wedged supports, in order to detect articular and dorsal screw protrusion. A comparison with computed tomography (CT) scan imaging has been made. The outcome of 26 patients with distal radius articular fracture, treated with a VFAP, is reported. Good correlation between modified X-rays and CT scan was observed. A sensitivity of 100% for articular protrusion and 66% for dorsal have been obtained. When detecting screw protrusion at the distal radius, the use of wedged supports to perform special X-rays intraoperatively is an effective tool.

  4. Computerized Adaptive Testing for Polytomous Motivation Items: Administration Mode Effects and a Comparison with Short Forms

    ERIC Educational Resources Information Center

    Hol, A. Michiel; Vorst, Harrie C. M.; Mellenbergh, Gideon J.

    2007-01-01

    In a randomized experiment (n = 515), a computerized and a computerized adaptive test (CAT) are compared. The item pool consists of 24 polytomous motivation items. Although items are carefully selected, calibration data show that Samejima's graded response model did not fit the data optimally. A simulation study is done to assess possible…

  5. Preoperative Computerized Tomography and Magnetic Resonance Imaging of the Pancreas Predicts Pancreatic Mass and Functional Outcomes After Total Pancreatectomy and Islet Autotransplant.

    PubMed

    Young, Michael C; Theis, Jake R; Hodges, James S; Dunn, Ty B; Pruett, Timothy L; Chinnakotla, Srinath; Walker, Sidney P; Freeman, Martin L; Trikudanathan, Guru; Arain, Mustafa; Robertson, Paul R; Wilhelm, Joshua J; Schwarzenberg, Sarah J; Bland, Barbara; Beilman, Gregory J; Bellin, Melena D

    2016-08-01

    Approximately two thirds of patients will remain on insulin therapy after total pancreatectomy with islet autotransplant (TPIAT) for chronic pancreatitis. We investigated the relationship between measured pancreas volume on computerized tomography or magnetic resonance imaging and features of chronic pancreatitis on imaging, with subsequent islet isolation and diabetes outcomes. Computerized tomography or magnetic resonance imaging was reviewed for pancreas volume (Vitrea software) and presence or absence of calcifications, atrophy, and dilated pancreatic duct in 97 patients undergoing TPIAT. Relationship between these features and (1) islet mass isolated and (2) diabetes status at 1-year post-TPIAT were evaluated. Pancreas volume correlated with islet mass measured as total islet equivalents (r = 0.50, P < 0.0001). Mean islet equivalents were reduced by more than half if any one of calcifications, atrophy, or ductal dilatation were observed. Pancreatic calcifications increased the odds of insulin dependence 4.0 fold (1.1, 15). Collectively, the pancreas volume and 3 imaging features strongly associated with 1-year insulin use (P = 0.07), islet graft failure (P = 0.003), hemoglobin A1c (P = 0.0004), fasting glucose (P = 0.027), and fasting C-peptide level (P = 0.008). Measures of pancreatic parenchymal destruction on imaging, including smaller pancreas volume and calcifications, associate strongly with impaired islet mass and 1-year diabetes outcomes.

  6. Computerized tomography-guided sphenopalatine ganglion pulsed radiofrequency treatment in 16 patients with refractory cluster headaches: Twelve- to 30-month follow-up evaluations.

    PubMed

    Fang, Luo; Jingjing, Lu; Ying, Shen; Lan, Meng; Tao, Wang; Nan, Ji

    2016-02-01

    Sphenopalatine ganglion percutaneous radiofrequency thermocoagulation treatment can improve the symptoms of cluster headaches to some extent. However, as an ablation treatment, radiofrequency thermocoagulation treatment also has side effects. To preliminarily evaluate the efficacy and safety of a non-ablative computerized tomography-guided pulsed radiofrequency treatment of sphenopalatine ganglion in patients with refractory cluster headaches. We included and analysed 16 consecutive cluster headache patients who failed to respond to conservative therapy from the Pain Management Center at the Beijing Tiantan Hospital between April 2012 and September 2013 treated with pulsed radiofrequency treatment of sphenopalatine ganglion. Eleven of 13 episodic cluster headaches patients and one of three chronic cluster headaches patient were completely relieved of the headache within an average of 6.3 ± 6.0 days following the treatment. Two episodic cluster headache patients and two chronic cluster headache patients showed no pain relief following the treatment. The mean follow-up time was 17.0 ± 5.5 months. All patients enrolled in this study showed no treatment-related side effects or complications. Our data show that patients with refractory episodic cluster headaches were quickly, effectively and safely relieved from the cluster period after computerized tomography-guided pulsed radiofrequency treatment of sphenopalatine ganglion, suggesting that it may be a therapeutic option if conservative treatments fail. © International Headache Society 2015.

  7. NOTE: Cone beam computerized tomography: the effect of calibration of the Hounsfield unit number to electron density on dose calculation accuracy for adaptive radiation therapy

    NASA Astrophysics Data System (ADS)

    Hatton, Joan; McCurdy, Boyd; Greer, Peter B.

    2009-08-01

    The availability of cone beam computerized tomography (CBCT) images at the time of treatment has opened possibilities for dose calculations representing the delivered dose for adaptive radiation therapy. A significant component in the accuracy of dose calculation is the calibration of the Hounsfield unit (HU) number to electron density (ED). The aim of this work is to assess the impact of HU to ED calibration phantom insert composition and phantom volume on dose calculation accuracy for CBCT. CBCT HU to ED calibration curves for different commercial phantoms were measured and compared. The effect of the scattering volume of the phantom on the HU to ED calibration was examined as a function of phantom length and radial diameter. The resulting calibration curves were used at the treatment planning system to calculate doses for geometrically simple phantoms and a pelvic anatomical phantom to compare against measured doses. Three-dimensional dose distributions for the pelvis phantom were calculated using the HU to ED curves and compared using Chi comparisons. The HU to ED calibration curves for the commercial phantoms diverge at densities greater than that of water, depending on the elemental composition of the phantom insert. The effect of adding scatter material longitudinally, increasing the phantom length from 5 cm to 26 cm, was found to be up to 260 HU numbers for the high-density insert. The change in the HU value, by increasing the diameter of the phantom from 18 to 40 cm, was found to be up to 1200 HU for the high-density insert. The effect of phantom diameter on the HU to ED curve can lead to dose differences for 6 MV and 18 MV x-rays under bone inhomogeneities of up to 20% in extreme cases. These results show significant dosimetric differences when using a calibration phantom with materials which are not tissue equivalent. More importantly, the amount of scattering material used with the HU to ED calibration phantom has a significant effect on the dosimetric

  8. Investigating the effect of characteristic x-rays in cadmium zinc telluride detectors under breast computerized tomography operating conditions

    PubMed Central

    Glick, Stephen J.; Didier, Clay

    2013-01-01

    A number of research groups have been investigating the use of dedicated breast computerized tomography (CT). Preliminary results have been encouraging, suggesting an improved visualization of masses on breast CT as compared to conventional mammography. Nonetheless, there are many challenges to overcome before breast CT can become a routine clinical reality. One potential improvement over current breast CT prototypes would be the use of photon counting detectors with cadmium zinc telluride (CZT) (or CdTe) semiconductor material. These detectors can operate at room temperature and provide high detection efficiency and the capability of multi-energy imaging; however, one factor in particular that limits image quality is the emission of characteristic x-rays. In this study, the degradative effects of characteristic x-rays are examined when using a CZT detector under breast CT operating conditions. Monte Carlo simulation software was used to evaluate the effect of characteristic x-rays and the detector element size on spatial and spectral resolution for a CZT detector used under breast CT operating conditions. In particular, lower kVp spectra and thinner CZT thicknesses were studied than that typically used with CZT based conventional CT detectors. In addition, the effect of characteristic x-rays on the accuracy of material decomposition in spectral CT imaging was explored. It was observed that when imaging with 50-60 kVp spectra, the x-ray transmission through CZT was very low for all detector thicknesses studied (0.5–3.0 mm), thus retaining dose efficiency. As expected, characteristic x-ray escape from the detector element of x-ray interaction increased with decreasing detector element size, approaching a 50% escape fraction for a 100 μm size detector element. The detector point spread function was observed to have only minor degradation with detector element size greater than 200 μm and lower kV settings. Characteristic x-rays produced increasing

  9. Acute Pyelonephritis Focusing on Perfusion Defects on Contrast Enhansed Computerized Tomography(CT) Scans and Its Clinical Outcome

    PubMed Central

    Ha, Sung-Kyu; Seo, Jung-Kun; Kim, Seung-Jung; Park, Seung-Ho; Park, Chong-Hoon; Lee, Ho-Yung; Han, Dae-Suk; Kim, Ki-Whang

    1997-01-01

    Objectives Many cases of acute pyelonephritis show renal perfusion defects on contrast enhanced computerized tomography (CT) imaging studies. The purpose of this study is to show the frequency of renal perfusion defects in uncomplicated acute pyelonephritis and to compare the clinical responses of patients who had perfusion defects or not. Methods We studied patients who had symptoms and signs of acute pyelonephritis through CT examinations with contrast enhancement. We identified 21 cases who had perfusion defects among 35 patients who had undergone CT imaging studies and compared the clinical data in the two groups of patients who had perfusion defects on CT (group 1) and who had not (group 2). Results Nearly all patients had typical symptoms and signs of acute pyelonephritis such as high fever and chill, flank pain and costovertebral angle tenderness. Combined clinical problems were septic shock (one case, 4.8%) and disseminated intravascular coagulation (DIC) (one case, 4.8%) in group 1. Laboratory findings were not different between the two groups. All patients were treated with antibiotics and had successful recoveries. The duration of recovery of pyuria in group 1 (5.2±9.6 days) was not longer than that in group 2(3.1±2.9 days) (p>0.05). The length of defeverscence in group 1 (7.0±4.6 days) was longer than in group 2 (3.5±2.7 days) (p<0.05). There were no differences between group 1 and group 2 in the rate of predisposing factors. Thirteen of 21 cases (61.9%) in group 1 and five of 14 cases (35.7%) in group 2 had positive urine culture results which are relatively low probably due to the administration of antibiotics prior to our emergency room visit. Perfusion defects on CT were very frequent findings (60.0% of the clinical acute pyelonephritis patients). We classified CT findings of group 1 as focal unilateral (2 cases, 9.5%), multifocal unilateral (14 cases, 66.7%) and multifocal bilateral (5 cases, 23.8%), and there were no differences between the

  10. [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.

  11. A Comparison of Cognitive Bias Modification for Interpretation and Computerized Cognitive Behavior Therapy

    PubMed Central

    Bowler, Jennifer O.; Mackintosh, Bundy; Dunn, Barnaby D.; Mathews, Andrew; Dalgleish, Tim; Hoppitt, Laura

    2012-01-01

    Objective: Computerized cognitive behavioral therapy (cCBT) and cognitive bias modification for interpretation (CBM-I) both have demonstrated efficacy in alleviating social anxiety, but how they compare with each other has not been investigated. The present study tested the prediction that both interventions would reduce anxiety relative to a no-intervention comparison condition, but CBM-I would be particularly effective at modifying threat-related cognitive bias under high mental load. Method: Sixty-three primarily Caucasian adults (mean age = 22.7, SD = 5.87; 68.3% female) with high social anxiety, randomly allocated to 3 groups: CBM-I (n = 21), cCBT (n = 21), and a no-intervention control group (n = 21) provided complete data for analysis. Pre- and postintervention (4 sessions lasting 2 weeks, control participants only attended the pre–post sessions) self-report measures of anxiety, depression, attentional control, and threat-related interpretive bias were completed. In addition, interpretive bias under high versus low cognitive load was measured using the Scrambled Sentences Test. Results: Both CBM-I and cCBT groups reported significantly reduced levels of social anxiety, trait anxiety, and depression and improved attentional control, relative to the control group, with no clear superiority of either active intervention. Although both active conditions reduced negative bias on the Scrambled Sentences Test completed under mental load, CBM-I was significantly more effective at doing so. Conclusions: The results suggest that although not differing in therapeutic efficacy, CBM-I and cCBT might differ in the resilience of their effects when under mental load. PMID:22963595

  12. Comparison of Deconvolution Filters for Photoacoustic Tomography

    PubMed Central

    Van de Sompel, Dominique; Sasportas, Laura S.; Jokerst, Jesse V.; Gambhir, Sanjiv S.

    2016-01-01

    In this work, we compare the merits of three temporal data deconvolution methods for use in the filtered backprojection algorithm for photoacoustic tomography (PAT). We evaluate the standard Fourier division technique, the Wiener deconvolution filter, and a Tikhonov L-2 norm regularized matrix inversion method. Our experiments were carried out on subjects of various appearances, namely a pencil lead, two man-made phantoms, an in vivo subcutaneous mouse tumor model, and a perfused and excised mouse brain. All subjects were scanned using an imaging system with a rotatable hemispherical bowl, into which 128 ultrasound transducer elements were embedded in a spiral pattern. We characterized the frequency response of each deconvolution method, compared the final image quality achieved by each deconvolution technique, and evaluated each method’s robustness to noise. The frequency response was quantified by measuring the accuracy with which each filter recovered the ideal flat frequency spectrum of an experimentally measured impulse response. Image quality under the various scenarios was quantified by computing noise versus resolution curves for a point source phantom, as well as the full width at half maximum (FWHM) and contrast-to-noise ratio (CNR) of selected image features such as dots and linear structures in additional imaging subjects. It was found that the Tikhonov filter yielded the most accurate balance of lower and higher frequency content (as measured by comparing the spectra of deconvolved impulse response signals to the ideal flat frequency spectrum), achieved a competitive image resolution and contrast-to-noise ratio, and yielded the greatest robustness to noise. While the Wiener filter achieved a similar image resolution, it tended to underrepresent the lower frequency content of the deconvolved signals, and hence of the reconstructed images after backprojection. In addition, its robustness to noise was poorer than that of the Tikhonov filter. The

  13. Single photon emission computerized tomography and histological evaluation in the validation of a new technique for closure of oro-antral communication: an experimental study in pigs.

    PubMed

    Ogunsalu, C O; Rohrer, M; Persad, Hari; Archibald, A; Watkins, J; Daisley, H; Ezeokoli, C; Adogwa, A; Legall, C; Khan, O

    2008-03-01

    Various bone regeneration techniques have evolved recently but controversies regarding vascularization and integration of such bone grafting techniques have led occasionally to animal experiment to validate such techniques. The objective of this study was to evaluate the evidence of vascularization and osseo-integration of a new bone regeneration technique utilized for the closure of oro-antral communication (OAC) by an experimental model in which Single Photon Emission computerized Tomography and histological studies were conducted in pigs. We conclude that the sandwich technique used for the closure of OAC results in a vascularized new bone formation which eventually osseo-integrate with the surrounding bone. Also, this experimental study confirmed that autogeneous bone graft was superior to xenografts when used within the sandwich unit.

  14. A Comparison of the Partial Credit and Graded Response Models in Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    De Ayala, R. J.; And Others

    1992-01-01

    A study involving 1,000 simulated examinees compared the partial credit and graded response models in computerized adaptive testing (CAT). The graded response model fit the data well and provided slightly more accurate ability estimates than those of the partial credit model. Benefits of polytomous model-based CATs are discussed. (SLD)

  15. A Comparison of Testlet-Based Test Designs for Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Schnipke, Deborah L.; Reese, Lynda M.

    Two-stage and multistage test designs provide a way of roughly adapting item difficulty to test-taker ability. All test takers take a parallel stage-one test, and, based on their scores, they are routed to tests of different difficulty levels in subsequent stages. These designs provide some of the benefits of standard computerized adaptive testing…

  16. Computerized Adaptive Testing: A Comparison of the Nominal Response Model and the Three Parameter Logistic Model.

    ERIC Educational Resources Information Center

    DeAyala, R. J.; Koch, William R.

    A nominal response model-based computerized adaptive testing procedure (nominal CAT) was implemented using simulated data. Ability estimates from the nominal CAT were compared to those from a CAT based upon the three-parameter logistic model (3PL CAT). Furthermore, estimates from both CAT procedures were compared with the known true abilities used…

  17. Comparison of ultrasound tomography methods in circular geometry

    NASA Astrophysics Data System (ADS)

    Leach, Richard, Jr.; Azevedo, Steve G.; Berryman, James G.; Bertete-Aguirre, Hugo; Chambers, David H.; Mast, Jeffrey E.; Littrup, Peter J.; Duric, Nebojsa; Johnson, Steven A.; Wuebbeling, Frank

    2002-04-01

    Extremely high quality data was acquired using an experimental ultrasound scanner developed at Lawrence Livermore National Laboratory using a 2D ring geometry with up to 720 transmitter/receiver transducer positions. This unique geometry allows reflection and transmission modes and transmission imaging and quantification of a 3D volume using 2D slice data. Standard image reconstruction methods were applied to the data including straight-ray filtered back projection, reflection tomography, and diffraction tomography. Newer approaches were also tested such as full wave, full wave adjoint method, bent-ray filtered backprojection, and full-aperture tomography. A variety of data sets were collected including a formalin-fixed human breast tissue sample, a commercial ultrasound complex breast phantom, and cylindrical objects with and without inclusions. The resulting reconstruction quality of the images ranges from poor to excellent. The method and results of this study are described including like-data reconstructions produced by different algorithms with side-by-side image comparisons. Comparisons to medical B-scan and x-ray CT scan images are also shown. Reconstruction methods with respect to image quality using resolution, noise, and quantitative accuracy, and computational efficiency metrics will also be discussed.

  18. A Comparison of Ultrasound Tomography Methods in Circular Geometry

    SciTech Connect

    Leach, R R; Azevedo, S G; Berryman, J G; Bertete-Aquirre, H R; Chambers, D H; Mast, J E; Littrup, P; Duric, N; Johnson, S A; Wuebbeling, F

    2002-01-24

    Extremely high quality data was acquired using an experimental ultrasound scanner developed at Lawrence Livermore National Laboratory using a 2D ring geometry with up to 720 transmitter/receiver transducer positions. This unique geometry allows reflection and transmission modes and transmission imaging and quantification of a 3D volume using 2D slice data. Standard image reconstruction methods were applied to the data including straight-ray filtered back projection, reflection tomography, and diffraction tomography. Newer approaches were also tested such as full wave, full wave adjoint method, bent-ray filtered back projection, and full-aperture tomography. A variety of data sets were collected including a formalin-fixed human breast tissue sample, a commercial ultrasound complex breast phantom, and cylindrical objects with and without inclusions. The resulting reconstruction quality of the images ranges from poor to excellent. The method and results of this study are described including like-data reconstructions produced by different algorithms with side-by-side image comparisons. Comparisons to medical B-scan and x-ray CT scan images are also shown. Reconstruction methods with respect to image quality using resolution, noise, and quantitative accuracy, and computational efficiency metrics will also be discussed.

  19. The potential for non-invasive study of mummies: validation of the use of computerized tomography by post factum dissection and histological examination of a 17th century female Korean mummy.

    PubMed

    Lim, Do-Seon; Lee, In Sun; Choi, Ki-Ju; Lee, Soong Deok; Oh, Chang Seok; Kim, Yi-Suk; Bok, Gi Dae; Kim, Myeung Ju; Yi, Yang Su; Lee, Eun-Joo; Shin, Dong Hoon

    2008-10-01

    The socio-cultural antipathies of some descendants with regard to invasive examinations of age-old human remains make permission for dissection of Korean mummies of the Joseon Dynasty (1392-1910) difficult to obtain. Overcoming this obstacle necessitated the use of non-invasive techniques, such as multi-detector computerized tomography (MDCT) and endoscopic examination, enabling determination of the preservation status of internal organs of mummies without significantly damaging the mummies themselves. However, MDCT alone cannot clearly differentiate specific mummified organs. Therefore, in much the same way as diagnostic radiologists make their MDCT readings on living patients more reliable by means of comparison with accumulated post-factum data from autopsies or histological studies, examinations of mummies by invasive techniques should not be decried as mere destruction of age-old human remains. Rather, providing that due permission from descendants and/or other relevant authorities can be obtained, dissection and histological examination should be performed whenever opportunities arise. Therefore, in this study, we compared the radiological data acquired from a 17th century mummy with our dissection results for the same subject. As accumulation of this kind of data could be very crucial for correct interpretation of MDCT findings on Korean mummies, we will perform similar trials on other Korean mummies found in forthcoming days if conditions permit.

  20. The potential for non-invasive study of mummies: validation of the use of computerized tomography by post factum dissection and histological examination of a 17th century female Korean mummy

    PubMed Central

    Lim, Do-Seon; Lee, In Sun; Choi, Ki-Ju; Lee, Soong Deok; Oh, Chang Seok; Kim, Yi-Suk; Bok, Gi Dae; Kim, Myeung Ju; Yi, Yang Su; Lee, Eun-Joo; Shin, Dong Hoon

    2008-01-01

    The socio-cultural antipathies of some descendants with regard to invasive examinations of age-old human remains make permission for dissection of Korean mummies of the Joseon Dynasty (1392–1910) difficult to obtain. Overcoming this obstacle necessitated the use of non-invasive techniques, such as multi-detector computerized tomography (MDCT) and endoscopic examination, enabling determination of the preservation status of internal organs of mummies without significantly damaging the mummies themselves. However, MDCT alone cannot clearly differentiate specific mummified organs. Therefore, in much the same way as diagnostic radiologists make their MDCT readings on living patients more reliable by means of comparison with accumulated post-factum data from autopsies or histological studies, examinations of mummies by invasive techniques should not be decried as mere destruction of age-old human remains. Rather, providing that due permission from descendants and/or other relevant authorities can be obtained, dissection and histological examination should be performed whenever opportunities arise. Therefore, in this study, we compared the radiological data acquired from a 17th century mummy with our dissection results for the same subject. As accumulation of this kind of data could be very crucial for correct interpretation of MDCT findings on Korean mummies, we will perform similar trials on other Korean mummies found in forthcoming days if conditions permit. PMID:19014355

  1. A comparison of paper-and-pencil and computerized forms of Line Orientation and Enhanced Cued Recall Tests.

    PubMed

    Aşkar, Petek; Altun, Arif; Cangöz, Banu; Cevik, Vildan; Kaya, Galip; Türksoy, Hasan

    2012-04-01

    The purpose of this study was to assess whether a computerized battery of neuropsychological tests could produce similar results as the conventional forms. Comparisons on 77 volunteer undergraduates were carried out with two neuropsychological tests: Line Orientation Test and Enhanced Cued Recall Test. Firstly, students were assigned randomly across the test medium (paper-and-pencil versus computerized). Secondly, the groups were given the same test in the other medium after a 30-day interval between tests. Results showed that the Enhanced Cued Recall Test-Computer-based did not correlate with the Enhanced Cued Recall Test-Paper-and-pencil results. Line Orientation Test-Computer-based scores, on the other hand, did correlate significantly with the Line Orientation Test-Paper-and-pencil version. In both tests, scores were higher on paper-and-pencil tests compared to computer-based tests. Total score difference between modalities was statistically significant for both Enhanced Cued Recall Tests and for the Line Orientation Test. In both computer-based tests, it took less time for participants to complete the tests.

  2. Independent comparison of CogState computerized testing and a standard cognitive battery with neuroimaging

    PubMed Central

    Mielke, Michelle M.; Weigand, Stephen D.; Wiste, Heather J.; Vemuri, Prashanthi; Machulda, Mary M.; Knopman, Davis S.; Lowe, Val; Roberts, Rosebud O.; Kantarci, Kejal; Rocca, Walter A.; Jack, Clifford R.; Petersen, Ronald C.

    2014-01-01

    Background Inexpensive, non-invasive tools for assessing Alzheimer-type pathophysiologies are needed. Computerized cognitive assessments are prime candidates. Methods Cognitively normal participants, aged 51-71, with MRI, FDG-PET, amyloid PET, CogState computerized cognitive assessment, and standard neuropsychological tests were included. We first examined the association between the CogState battery and neuroimaging measures. We then compared that association to the one between standard neuropsychological z-scores and neuroimaging. Results Slower reaction times for CogState Identification and One Back, and lower memory and attention z-scores, were associated (P<.05) with FDG-PET hypometabolism. Slower time on the Groton Maze Learning Task and worse One Card Learning accuracy were associated (P<.05) with smaller hippocampal volumes. There were no associations with amyloid PET. Associations of CogState and neuropsychological z-scores with neuroimaging were small and of a similar magnitude. Conclusions CogState subtests were cross-sectionally comparable to standard neuropsychological tests in their relatively weak associations with neurodegeneration imaging markers. PMID:25458308

  3. An architecture for online comparison and validation of processing methods and computerized guidelines in intensive care units.

    PubMed

    Allart, L; Vilhelm, C; Mehdaoui, H; Hubert, H; Sarrazin, B; Zitouni, D; Lemdani, M; Ravaux, P

    2009-01-01

    Clinical decision support systems are a combination of software techniques to help the clinicians in their medical decision making process via functionalities ranging from basic signal analysis to therapeutic planning and computerized guidelines. The algorithms providing all these functionalities must be very carefully validated on real patient data and must be confronted to everyday clinical practice. One of the main problems when developing these techniques is the difficulty to obtain high-quality complete patient records, comprising data coming both from the biomedical equipment (high-frequency signals), and from numerous other sources (therapeutics, imagery, clinical actions, etc.). In this paper, we present an infrastructure for developing and testing such software algorithms. It is based on a bedside workstation where testing different algorithms simultaneously on real-time data is possible in the ward. It is completed by a collaborative portal enabling different teams to test their software algorithms on the same patient records, making comparisons and cross-validations more easily.

  4. [Computerized tomography in craniocerebral, maxillofacial, cervical, and spinal gunshot wounds. Part II--Clinical contribution and medico- legal aspects].

    PubMed

    Scialpi, M; Boccuzzi, F; Romeo, F; Ax, G; Scapati, C; Rotondo, A; Angelelli, G

    1996-12-01

    To assess the diagnostic and medicolegal contribution of Computed Tomography (CT) in patients with craniocerebral, maxillofacial, neck and spine gunshot wounds, we submitted to CT 106 patients with gunshot wounds examined over a 7-year period (February, 1988 to December, 1994). Twenty-four of them had craniocerebral injuries (23%), 9 maxillofacial (8%), 8 neck (8%) and 10 vertebral (9%) injuries. Emergency CT demonstrated the mechanism of the injury, the bullet path and site, the site of bone and/or metallic fragments, and damage extent. In all perforating cranioencephalic injuries (n = 7) intracerebral or extrathecal bone fragments were demonstrated adjacent to the bullet entrance and exit holes, respectively. In injury monitoring. CT showed injury evolution, retained fragments and complications, thus enabling damage extent assessment. High Resolution Computed Tomography (HRCT) was useful in locating minute orbitary retrobulbar and intraspinal fragments. Magnetic Resonance (MR) Imaging in postoperative patients proved a valuable tool to assess the extent of spinal cord damage. To conclude, CT is a useful technique to examine the patients with gunshot wounds, which helps plan adequate treatment and solve complex medicolegal problems.

  5. A Family with Von Hippel-Lindau Syndrome: The Findings of Indium-111 Somatostatin Receptor Scintigraphy, Iodine-123 Metaiodobenzylguanidine Scintigraphy and Single Photon Emission Computerized Tomography

    PubMed Central

    Arıcan, Pelin; Okudan Tekin, Berna; Naldöken, Seniha; Şefizade, Rıza; Berker, Dilek

    2017-01-01

    Von Hippel-Lindau syndrome (VHLS) is an autosomal dominant hereditary familial disorder characterized by development of malignant and benign neoplasms. Differential diagnosis of the adrenal and pancreatic masses are difficult in patients with VHLS. Iodine-123 metaiodobenzylguanidine (I-123 MIBG) and indium-111 somatostatin receptor scintigraphies (In-111 SRS) have important roles in the differential diagnosis of adrenal and pancreatic masses in those patients. In this case report, we present the findings of I-123 MIBG single-photon emission computerized tomography (SPECT/CT) and In-111 SRS SPECT/CT in three members of a family with VHLS. In case 1, a residual neuroendocrine tumor (NET) was detected in the head of pancreas on In-111 SRS SPECT/CT images. In case 2 and 3, I-123 MIBG SPECT/CT confirmed the adrenal masses as pheochromocytoma, and the extra-adrenal mass as NET, before surgery. We thought that In-111 SRS and I-123 MIBG scan might be helpful in the routine work up of VHLS patients for diagnostic and therapeutic purposes. Hybrid SPECT/CT system may improve diagnostic accuracy of planar images since it assesses morphologic and functional information together. PMID:28291009

  6. Initial experience with SPECT (single-photon computerized tomography) of the brain using N-isopropyl I-123 p-iodoamphetamine: concise communication

    SciTech Connect

    Hill, T.C.; Holman, B.L.; Lovett, R.; O'Leary, D.H.; Front, D.; Magistretti, P.; Zimmerman, R.E.; Moore, S.; Clouse, M.E.; Wu, J.L.; Lin, T.H.; Baldwin, R.M.

    1982-03-01

    Forty-six patients were studied with N-isopropyl I-123 p-iodoamphetamine (IMP) and the Harvard Scanning Multidetector Brain System. In nine control patients, good differentiation between the gray and white matter of the cerebral cortex and the basal ganglia was evident. Regional uptake was affected by physiologic maneuvers (visual stimulation). In 24 patients studied for stroke, IMP images demonstrated areas that were involved in acute infarction in eight patients whose initial transmission computerized tomography (TCT) was normal; IMP also showed perfusion abnormalities larger than the TCT abnormality in ten patients. Perfusion abnormalities were present in 23/24 of these patients. Seven patients studied with a history of TIA had normal TCT and IMP images. In three patients studied during seizure activity, regions of hyperperfusion corresponded to the EEG seizure focus. Markedly decreased activity was present in three patients with brain tumor and corresponded to the focal abnormality on the TCT study. Our study demonstrates the feasibility of assessing regional brain perfusion using a radiopharmaceutical that is lipid soluble and has a high extraction fraction in the brain, together with single-photon ECT.

  7. Reconstruction of Three-Dimensional Sound Field from Two-Dimensional Sound Field Using Optical Computerized Tomography and Near-Field Acoustical Holography

    NASA Astrophysics Data System (ADS)

    Ohbuchi, Takeshi; Mizutani, Koichi; Wakatsuki, Naoto; Nishimiya, Kojiro; Masuyama, Hiroyuki

    2009-07-01

    We propose a method for reconstruction of a three-dimensional sound field using optical computerized tomography (O-CT) and near-field acoustical holography (NAH). The center of a transducer is the origin, and a sound wave is radiated along the z-axis. An ultrasonic wave affects the phase of light passing through the sound field, and the phase change is determined using a Michelson interferometer. Projections of the underwater sound field were obtained by mechanical scanning, and the sound field was reconstructed from 18 of these projections by O-CT. To determine sound velocity for reconstruction of the three-dimensional sound field, two-dimensional sound fields at z = 40 and 41 mm were reconstructed using O-CT in a region of 28 ×28 mm2. The sound velocity was determined to be 1508 m/s using inverse analysis of NAH. Using NAH and the determined sound velocity, the three-dimensional sound field of 28 ×28 ×5 mm3 was reconstructed from the two-dimensional sound field at z = 40 mm. The sound field reconstructed using NAH was in good agreement with the sound field reconstructed using O-CT.

  8. Incidence of normal pineal and chroids plexus calcification on brain CT (computerized tomography) at Tikur Anbessa Teaching Hospital Addis Ababa, Ethiopia.

    PubMed

    Admassie, Daniel; Mekonnen, Abebe

    2009-01-01

    To determine the incidence of normal calcification of pineal gland and choroids plexus on Brain -CT (computerized Tomography) and to see its association with age and sex. A cross-sectional descriptive study was conducted at Radiology Department, Tikur Anbessa Teaching Hospital, Addis Ababa, Ethiopia from May 2001 to August 2002. A total of 518 patients; 312 males and 206 females underwent brain-CT without pineal or choroids plexus pathology. The over all incidence of normal pineal gland calcification was 72.0 % and that of choroid plexus 43.3 %. The incidence of normal pineal gland and choroids plexus calcification were higher in males than in females by 13.1% and 6.0% respectively. The frequency of pineal gland and choroids plexus calcification showed a steady increase with age on both sex groups. The incidence of normal pineal gland calcification in this study is similar to most of the findings of other studies while the incidence of choroids plexus calcification was lower as compared the finding of other studies.

  9. Clinical significance of right ventricular activity on treadmill thallium-201 myocardial single-photon emission computerized tomography using cadmium-zinc-telluride cameras.

    PubMed

    Ko, Kuan-Yin; Wu, Yen-Wen; Liu, Chia-Ju; Cheng, Mei-Fang; Yen, Ruoh-Fang; Tzen, Kai-Yuan

    2016-06-01

    Identification of right ventricular (RV) abnormalities is important in patients with suspected coronary artery disease (CAD). RV activity can be better visualized on myocardial single-photon emission computerized tomography (SPECT) using a higher sensitivity cadmium-zinc-telluride (CZT) detector. The aim of this study was to investigate the clinical significance of RV/left ventricular (LV) uptake ratios during exercise thallium-201 SPECT using CZT detectors. A total of 102 patients underwent treadmill ECG-gated SPECT, coronary angiography, and echocardiography. SPECT myocardial perfusion was interpreted using a 17-segment model and a 0-4-point scale. RV/LV uptake ratios were calculated on the basis of maximum counts per pixel within the entire RV and LV walls. The relationships between RV/LV uptake ratio and gated SPECT, presence of CAD (≥50% stenosis in the left main or ≥70% in the main branches), demographics, and echocardiographic parameters were analyzed. Stress RV/LV ratios correlated positively with the presence of left main or multivessel disease, and tricuspid regurgitation maximum pressure gradient. After multivariate regression, stress/rest RV/LV ratios correlated positively with mitral flow deceleration time, age, female sex, and use of β-blockers. RV/LV uptake ratios on the basis of exercise myocardial perfusion SPECT imaging using CZT cameras are useful for the detection of severe CAD and could serve as an indicator of pulmonary hypertension and LV diastolic dysfunction.

  10. [The evaluation of early pulmonary involvement with high resolution computerized tomography in asymptomatic and non-smoker patients with rheumatoid arthritis].

    PubMed

    Karazincir, Sinem; Akoğlu, Sebahat; Güler, Hayal; Balci, Ali; Babayiğit, Cenk; Eğilmez, Ertuğrul

    2009-01-01

    To investigate pulmonary involvement by high resolution computerized tomography (HRCT) in patients with rheumatoid arthritis (RA) who are asymptomatic and lifelong non-smoker. Twenty-five patients with RA who are asymptomatic and lifelong non-smoker were included in the study. After clinical and laboratory investigations, plain chest X-rays, pulmonary function tests (PFT) and HRCT were performed. End expiratory HRCT slices were obtained for air trapping. Chest X-ray, PFT and HRCT findings showed 12%, 16%, 48% abnormalities, respectively. Interstitial involvement was the most common finding on HRCT (36%) and followed by air trapping (20%). Bronchiectasis, pulmonary nodule, and pleural disease were seen in 16%, 12%, and 12% of patients, respectively. None of patients had emphysema and honeycomb pattern. There was no statistically significant correlation between HRCT findings and disease activity criteria, RF positivity, PFT results and duration of the disease. Our study shows that pulmonary involvement is not always together with respiratory symptoms and impaired pulmonary function in patients with RA. New studies are needed which investigating the effects of radiologically detected lung involvement on prediction of survival and treatment choice in asymptomatic and nonsmoker RA patients.

  11. Circular gratings' moiré effect for projection measurement in volume optical computerized tomography with two-step phase-shifting method

    NASA Astrophysics Data System (ADS)

    Wang, Jia; Song, Yang; Li, Zhen-hua; He, An-zhi

    2012-11-01

    Volume optical computerized tomography (VOCT), which can realize real 3D measurement rather than traditional 2D OCT, has great superiority in quantitatively measuring the thermo physical parameters of transient flow field. Among the refractive index reconstruction techniques, filtered back-projection (FBP) method performs better than algebraic reconstruction techniques (ARTs) with higher accuracy and computationally efficient. In order to apply FBP to VOCT, the radial second-order derivative of projection wave front passes through the tested phase object should be obtained firstly. In this paper, a projection device with two circular gratings is established. In particular, owing to an inherent phase shift exists between moiré fringes of +1 and -1 diffraction orders, a two-step phase-shifting algorithm is utilized to extract the wave front's radial first-order derivative which is contained in the moiré fringes. The reliability of the two-step phase-shifting algorithm is proved by a computer simulation. Finally, the radial first-order derivative of wave front passing through a propane flame is measured and retrieved by these methods.

  12. A comparison of stopping rules for computerized adaptive screening measures using the rating scale model.

    PubMed

    Leroux, Audrey J; Dodd, Barbara G

    2014-01-01

    The current study evaluates three stopping rules for computerized adaptive testing (CAT): the predicted standard error reduction (PSER), the fixed-length, and the minimum SE using Andrich's rating scale model with a survey to identify at-risk students. PSER attempts to reduce the number of items administered and increase measurement precision of the trait. Several variables are manipulated, such as trait distribution and item pool size, in order to evaluate how these conditions interact and potentially help improve the correct classification of students. The findings indicate that the PSER stopping rule may be preferred when wanting to correctly diagnose or classify students at-risk and at the same time alleviate test burden for those taking screening measures based on the rating scale model with smaller item pools.

  13. Comparison of individual follow-up and computerized record linkage using the Canadian Mortality Data Base.

    PubMed

    Shannon, H S; Jamieson, E; Walsh, C; Julian, J A; Fair, M E; Buffet, A

    1989-01-01

    We compared two methods of ascertaining mortality in a historical prospective mortality study. Computerized Record Linkage (CRL) with the centralized historical Canadian Mortality Data Base (CMDB) was carried out on 2469 men and an attempt was also made to trace the subjects by individual follow-up (IFU). All but 88 were traced and 60 were reported to be dead. CRL was able to locate the deaths of three men who had been untraced by IFU. Contradictory information on vital status was obtained on 5 subjects--in 4 of them, the discrepancy was resolved in favour of CRL. Overall, CRL using the CMDB performed very well. We also consider factors that affect the relative costs of the two methods, which should be balanced against the accuracy of information obtained.

  14. Comparison of Computerized Sway Referencing and Standing on a Compliant Surface

    NASA Technical Reports Server (NTRS)

    Dean, S. Lance; Paloski, William H.; Wood, Scott J.

    2009-01-01

    Background: By removing vision and altering somatosensory inputs, we can examine the contributions of the vestibular system on balance control. Computerized Dynamic Posturography (CDP) systems accomplish this by using a dynamic plate that moves in proportion to the sway of the subject. A potential alternative to CDP is the use of a compliant foam surface. The goal of this study was to compare postural sway during each condition. Methods: Thirty-two healthy subjects (16 male and 16 female) were tested on a Equitest computerized posturography system and on a 5 inch thick block of foam (NeuroCom International; Clackamas, OR). Subjects performed three trials with their head erect and five trials with dynamic head tilts ( 20 at 0.33Hz) in the anterior-posterior (AP) plane. Subjects were instructed to stand quietly with their arms folded and eyes closed for each trial lasting 20 seconds. The sway in both AP and medial-lateral (ML) planes was calculated for each trial, as well as the total sway path length. Results: In general, AP sway tended to be greater on the Equitest than on foam and greater during the head movement trials than the head erect. The ML sway was consistently higher on foam and did not vary between head erect and moving conditions. Sway path length was consistently greater for head erect trials on foam and tended to be greater for head movement trials on the Equitest. The addition of head movements increases AP sway and the total path length. Conclusions: Based on the increase of sway in the ML direction, it is important to quantify sway in all directions when on a compliant foam surface.

  15. 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.

  16. Clinical significance of mesenteric panniculitis-like abnormalities on abdominal computerized tomography in patients with malignant neoplasms

    PubMed Central

    Ehrenpreis, Eli D; Roginsky, Grigory; Gore, Richard M

    2016-01-01

    AIM To clarify the association of malignancy with mesenteric panniculitis-like changes on computed tomography (CT). METHODS All abdominal CT scans performed at NorthShore University HealthSystem showing mesenteric panniculitis from January 2005 to August 2010 were identified in the Radnet (RadNet Corporation, Los Angeles, CA) database. Patients with a new or known diagnosis of a malignancy were included for this analysis. Longitudinal clinical histories were obtained from electronic medical records. RESULTS In total, 147794 abdominal CT scans were performed during the study period. Three hundred and fifty-nine patients had mesenteric panniculitis (MP)-like abnormalities on their abdominal CT. Of these patients, 81 patients (22.6%) had a known history of cancer at the time of their CT scan. Nineteen (5.3%) had a new diagnosis of cancer in concurrence with their CT, but the majority of these (14/19, 74%) were undergoing CT as part of a malignancy evaluation. Lymphomas were the most common cancers associated with MP-like findings on CT (36 cases, 36%), with follicular lymphoma being the most frequent subtype (17/36). A variety of solid tumors, most commonly prostate (7) and renal cell cancers (6) also were seen. CT follow up was obtained in 56 patients. Findings in the mesentery were unchanged in 45 (80%), worsened in 6 (11%), and improved in 5 patients (9%). Positron emission tomography (PET) scans performed in 44 patients only showed a positive uptake in the mesenteric mass in 2 patients (5%). CONCLUSION A new diagnosis of cancer is uncommon in patients with CT findings suggestive of MP. MP-like mesenteric abnormalities on CT generally remain stable in patients with associated malignancies. PET scanning is not recommended in the evaluation of patients with mesenteric panniculitis-like findings on CT. PMID:28082812

  17. High Resolution Chest Computerized Tomography in the Diagnosis of Ocular Sarcoidosis in a High TB Endemic Population.

    PubMed

    Babu, Kalpana; Shukla, Sai Bhakti; Philips, Mariamma

    2017-04-01

    To review the role of high resolution chest computed tomography (HRCT) in ocular sarcoidosis in a high TB endemic population. This was a retrospective study. Out of 140 cases, 54 had ocular sarcoidosis, while 86 cases had ocular tuberculosis. Abnormal HRCT findings was noted in 52 cases (96.3%) of ocular sarcoidosis compared with 55 cases (64.7%) of ocular tuberculosis (p = 0.001). Mediastinal lymphadenopathy was the most common finding in both groups (p = 0.544). Hilar lymphadenopathy and fissural nodules were significantly seen in ocular sarcoidosis (p = 0.001). Necrosis was seen in three cases of ocular sarcoidosis. In nearly half of the cases, it was not possible to differentiate between sarcoidosis and tuberculosis on HRCT. HRCT is a useful diagnostic tool in ocular sarcoidosis. Bilateral hilar lymphadenopathy and fissural nodules are significant findings in ocular sarcoidosis. A confident diagnosis of ocular sarcoidosis is made by the amalgamation of results of clinical, radiologic, and other laboratory investigations.

  18. [Role of computerized tomography following transrectal air insufflation and hypotonization and transrectal ultrasonography in the staging of rectal tumors].

    PubMed

    Osti, M F; Scattoni Padovan, F; Meli, C; Pirolli, C; Sbarbati, S; Notarianni, E; De Angelis d'Ossat, M; Anaveri, G

    1996-11-01

    Computed Tomography (CT) with rectal air inflation was compared with transrectal ultrasound (TRUS) in the preoperative staging of lower rectal cancer in 126 patients. Precontrast and postcontrast CT scans were performed with 5 mm thick slices; the rectum was previously inflated with air and antiperistaltic agents were administered. Preoperative results were compared with histologic findings. The accuracy, sensitivity and specificity of CT in predicting perirectal spread were 76%, 62% and 83%, whereas the corresponding figures for TRUS were 84%, 69% and 92%. The accuracy, sensitivity and specificity of CT and TRUS for nodal involvement were 58%, 60%, 57% and 72%, 68% and 66%, respectively. These results show that TRUS predicts perirectal spread and detects nodal metastases better than CT. However CT, when performed appropriately, shows tumor spread into perirectal fat and locoregional lymph nodes with high accuracy. Lymphatic involvement is strictly correlated with tumor size: TRUS and CT correctly staged only 57% and 43%, respectively, of the cases with nodal metastases and max. diameter of 5 mm. TRUS sometimes overstaged perirectal tumor growth (13 patients in our series) due to perirectal inflammation (9 cases) or artifacts caused by the presence of air bubbles between the probe and the tumor surface (4 patients). TRUS is a very useful tool for detecting tumor distance from the anal opening; in our series, the distance was incorrectly calculated only in one case (3 cm with TRUS versus 4 cm at surgery).

  19. Qualitative comparison of anatomical microdissection, Sihler's staining and computerized reconstruction methods for visualizing intramuscular nerve branches.

    PubMed

    Gülekon, Nadir; Peker, Tuncay; Turgut, Hasan Basri; Anil, Afitap; Karaköse, Mustafa

    2007-07-01

    STATING BACKGROUND: This study was designed to examine the entire intramuscular nerve distribution pattern of various human skeletal muscles in fetuses. In the present study rhomboid major, trapezius, long head of the biceps femoris and masseter muscles were investigated in five 18 weeks old fetal cadavers. Anatomical microdissection was applied to one fetal cadaver. In two fetuses, the extramuscular (main), major and minor nerve branches, and anastomosis were examined using Sihler's staining and labeling. In the remaining two fetuses, consecutive slices with 0.5 mm interval and 5 microm thickness were obtained from each skeletal muscle. These slices were stained with S100 for the demonstration of the nerve fibers and thereafter 3D reconstruction images were constituted using PC software. Anatomical microdissection, Sihler's staining and computerized reconstruction methods were compared to demonstrate the intramuscular nerve distribution pattern. Demonstration of the intramuscular minor nerve branches and anastomosis showed difficulties in anatomical dissected specimens when compared with three-dimensionally reconstructed images and specimens obtained with Sihler's staining technique. Nevertheless, anatomical dissection is a simple method whereas Sihler's technique and computer aided 3D reconstruction are complex methods and take a long time to complete. The obtained information exposed that staining technique and the 3D reconstructions appeared to provide better results than did anatomical dissection.

  20. Computerized tomography based “patient specific blocks” improve postoperative mechanical alignment in primary total knee arthroplasty

    PubMed Central

    Vaishya, Raju; Vijay, Vipul; Birla, Vikas P; Agarwal, Amit K

    2016-01-01

    AIM: To compare the postoperative mechanical alignment achieved after total knee arthroplasty (TKA) using computer tomography (CT) based patient specific blocks (PSB) to conventional instruments (CI). METHODS: Total 80 knees were included in the study, with 40 knees in both the groups operated using PSB and CI. All the knees were performed by a single surgeon using the same cruciate sacrificing implants. In our study we used CT based PSB to compare with CI. Postoperative mechanical femoro-tibial angle (MFT angle) was measured on long leg x-rays using picture archiving and communication system (PACS). We compared mechanical alignment achieved using PSB and CI in TKA using statistical analysis. RESULTS: The PSB group (group 1) included 17 females and seven males while in CI group (group 2) there were 15 females and eight males. The mean age of patients in group 1 was 60.5 years and in group 2 it was 60.2 years. The mean postoperative MFT angle measured on long-leg radiographs in group 1 was 178.23° (SD = 2.67°, range: 171.9° to 182.5°) while in group 2, the mean MFT angle was 175.73° (SD = 3.62°, range: 166.0° to 179.8°). There was significant improvement in postoperative mechanical alignment (P value = 0.001), in PSB group compared to CI. Number of outliers were also found to be less in group operated with PSB (7 Knee) compared to those operated with CI (17 Knee). CONCLUSION: PSB improve mechanical alignment after total knee arthroplasty, compared to CI. This may lead to lower rates of revision in the PSB based TKA as compared to the conventional instrumentation. PMID:27458553

  1. Computerized Automated Quantification of Subcutaneous and Visceral Adipose Tissue From Computed Tomography Scans: Development and Validation Study

    PubMed Central

    Kim, Young Jae; Park, Ji Won; Kim, Jong Wan; Park, Chan-Soo; Gonzalez, John Paul S; Lee, Seung Hyun

    2016-01-01

    Background Computed tomography (CT) is often viewed as one of the most accurate methods for measuring visceral adipose tissue (VAT). However, measuring VAT and subcutaneous adipose tissue (SAT) from CT is a time-consuming and tedious process. Thus, evaluating patients’ obesity levels during clinical trials using CT scans is both cumbersome and limiting. Objective To describe an image-processing-based and automated method for measuring adipose tissue in the entire abdominal region. Methods The method detects SAT and VAT levels using a separation mask based on muscles of the human body. The separation mask is the region that minimizes the unnecessary space between a closed path and muscle area. In addition, a correction mask, based on bones, corrects the error in VAT. Results To validate the method, the volume of total adipose tissue (TAT), SAT, and VAT were measured for a total of 100 CTs using the automated method, and the results compared with those from manual measurements obtained by 2 experts. Dice’s similarity coefficients (DSCs) between the first manual measurement and the automated result for TAT, SAT, and VAT are 0.99, 0.98, and 0.97, respectively. The DSCs between the second manual measurement and the automated result for TAT, SAT, and VAT are 0.98, 0.98, and 0.97, respectively. Moreover, intraclass correlation coefficients (ICCs) between the automated method and the results of the manual measurements indicate high reliability as the ICCs for the items are all .99 (P<.001). Conclusions The results described in this paper confirm the accuracy and reliability of the proposed method. The method is expected to be both convenient and useful in the clinical evaluation and study of obesity in patients who require SAT and VAT measurements. PMID:26846251

  2. Computerized Automated Quantification of Subcutaneous and Visceral Adipose Tissue From Computed Tomography Scans: Development and Validation Study.

    PubMed

    Kim, Young Jae; Park, Ji Won; Kim, Jong Wan; Park, Chan-Soo; Gonzalez, John Paul S; Lee, Seung Hyun; Kim, Kwang Gi; Oh, Jae Hwan

    2016-02-04

    Computed tomography (CT) is often viewed as one of the most accurate methods for measuring visceral adipose tissue (VAT). However, measuring VAT and subcutaneous adipose tissue (SAT) from CT is a time-consuming and tedious process. Thus, evaluating patients' obesity levels during clinical trials using CT scans is both cumbersome and limiting. To describe an image-processing-based and automated method for measuring adipose tissue in the entire abdominal region. The method detects SAT and VAT levels using a separation mask based on muscles of the human body. The separation mask is the region that minimizes the unnecessary space between a closed path and muscle area. In addition, a correction mask, based on bones, corrects the error in VAT. To validate the method, the volume of total adipose tissue (TAT), SAT, and VAT were measured for a total of 100 CTs using the automated method, and the results compared with those from manual measurements obtained by 2 experts. Dice's similarity coefficients (DSCs) between the first manual measurement and the automated result for TAT, SAT, and VAT are 0.99, 0.98, and 0.97, respectively. The DSCs between the second manual measurement and the automated result for TAT, SAT, and VAT are 0.98, 0.98, and 0.97, respectively. Moreover, intraclass correlation coefficients (ICCs) between the automated method and the results of the manual measurements indicate high reliability as the ICCs for the items are all .99 (P<.001). The results described in this paper confirm the accuracy and reliability of the proposed method. The method is expected to be both convenient and useful in the clinical evaluation and study of obesity in patients who require SAT and VAT measurements.

  3. Computerized Macular Pathology Diagnosis in Spectral Domain Optical Coherence Tomography Scans Based on Multiscale Texture and Shape Features

    PubMed Central

    Liu, Yu-Ying; Chen, Mei; Wollstein, Gadi; Duker, Jay S.; Fujimoto, James G.; Schuman, Joel S.; Rehg, James M.

    2011-01-01

    Purpose. To develop an automated method to identify the normal macula and three macular pathologies (macular hole [MH], macular edema [ME], and age-related macular degeneration [AMD]) from the fovea-centered cross sections in three-dimensional (3D) spectral-domain optical coherence tomography (SD-OCT) images. Methods. A sample of SD-OCT macular scans (macular cube 200 × 200 or 512 × 128 scan protocol; Cirrus HD-OCT; Carl Zeiss Meditec, Inc., Dublin, CA) was obtained from healthy subjects and subjects with MH, ME, and/or AMD (dataset for development: 326 scans from 136 subjects [193 eyes], and dataset for testing: 131 scans from 37 subjects [58 eyes]). A fovea-centered cross-sectional slice for each of the SD-OCT images was encoded using spatially distributed multiscale texture and shape features. Three ophthalmologists labeled each fovea-centered slice independently, and the majority opinion for each pathology was used as the ground truth. Machine learning algorithms were used to identify the discriminative features automatically. Two-class support vector machine classifiers were trained to identify the presence of normal macula and each of the three pathologies separately. The area under the receiver operating characteristic curve (AUC) was calculated to assess the performance. Results. The cross-validation AUC result on the development dataset was 0.976, 0.931, 0939, and 0.938, and the AUC result on the holdout testing set was 0.978, 0.969, 0.941, and 0.975, for identifying normal macula, MH, ME, and AMD, respectively. Conclusions. The proposed automated data-driven method successfully identified various macular pathologies (all AUC > 0.94). This method may effectively identify the discriminative features without relying on a potentially error-prone segmentation module. PMID:21911579

  4. Contrast-enhanced ultrasound and computerized tomography perfusion imaging of a liver fibrosis-early cirrhosis in dogs.

    PubMed

    Liu, Huanghui; Liu, Jun; Zhang, Yaqin; Liao, Jian; Tong, Qiongjuan; Gao, Feng; Hu, Yuequn; Wang, Wei

    2016-09-01

    To assess liver fibrosis stages in a liver fibrosis-early cirrhosis model in dogs, the clinical efficiency of contrast-enhanced ultrasound (CEUS) and computed tomography (CT) perfusion imaging were compared. Hepatic vein arriving time (HVAT), hepatic artery arriving time, and hepatic artery to vein transit time (HA-VTT) were measured on CEUS. Total liver perfusion (TLP), portal vein perfusion (PVP), hepatic artery perfusion, and hepatic perfusion index (HPI) were measured on CT perfusion imaging. Histologic examination of liver specimens of the animals was performed to assess the fibrosis stage. For assessment of liver fibrosis, the area under the receiver operating characteristic curve of CEUS indexes HVAT and HA-VTT were 0.865 and 0.930, respectively; the perfusion CT indexes TLP, PVP, and HPI were 0.797, 0.800, and 0.220, respectively; the serological index hyaluronic acid was 0.793. While for assessment of early cirrhosis, the area under the receiver operating characteristic curve of CEUS indexes HVAT and HA-VTT were 0.915 and 0.948, respectively; the perfusion CT indexes TLP, PVP, and HPI were 0.737, 0.765, and 0.218, respectively; the serological index hyaluronic acid was 0.627. This study showed that both CEUS and CT perfusion imaging have the potential to be complementary imaging tools in the evaluation of liver fibrosis. While CEUS is the better choice and the index HA-VTT can be considered as non-invasive semi-quantitative indexes for diagnosing liver fibrosis and early cirrhosis. © 2016 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

  5. Comparison of optical coherence tomography imaging of cataracts with histopathology

    NASA Astrophysics Data System (ADS)

    DiCarlo, Cheryl D.; Roach, William P.; Gagliano, Donald A.; Boppart, Stephen A.; Hammer, Daniel X.; Cox, Ann B.; Fujimoto, James G.

    1999-10-01

    This paper presents a comparison of in vivo optical coherence tomography (OCT) captured cataract images to subsequent histopathological examination of the lenticular opacities. OCT imaging was performed on anesthetized Rhesus monkeys, known as the delayed effects colony (DEC), with documented cataracts. These monkeys were exposed to several types of radiation during the mid and late 1960s. The radiation and age related cataracts in these animals were closely monitored using a unique grading system developed specifically for the DEC. In addition to this system, a modified version of a common cataract grading scheme for use in humans was applied. Of the original 18 monkeys imaged, lenses were collected at necropsy from seven of these animals, processed, and compared to OCT images. Results showed a direct correlation between the vertical OCT images and the cataractous lesions seen on corresponding histopathological sections of the lenses. Based on the images obtained and their corresponding documented comparison to histopathology, OCT showed tremendous potential to aid identification and characterization of cataracts. There can be artifactual problems with the images related to movement and shadows produced by opacities. However, with the advent of increased speed in imaging and multiplanar imaging, these disadvantages may easily be overcome.

  6. Dosimetry of Three Cone Beam Computerized Tomography Scanners at Different Fields of View in Terms of Various Head and Neck Organs

    PubMed Central

    Nikneshan, Sima; Aghamiri, Mahmood Reza; Moudi, Ehsan; Bahemmat, Nika; Hadian, Hoora

    2016-01-01

    Background Marketing new radiography devices necessitates documenting their absorbed X-ray doses. Since the current literature lacks studies on new devices, we assessed the doses of two new devices that had not previously been assessed. Objectives The new devices were compared to the Promax three dimensional (3D) scanner at two fields of view (FOV) in nine critical head and neck tissues and organs. Materials and Methods Seventeen thermoluminescence dosimeters positioned in an average-sized male RANDO phantom were used to determine the dosimetry of the three cone beam computerized tomography devices (NewTom VGi, NewTom 5G, and Promax 3D) at two field of views (FOVs), one small and one large. The exposure by each device per FOV was performed five times (30 exposures). The absorbed and effective doses were calculated for the thyroid, parotid, submandibular gland, sublingual gland, calvarium, cervical vertebra, trunk of the mandible, and mandibular ramus. The doses pertaining to the different devices, the FOVs, and the tissues were compared using the Kruskal-Wallis, Mann-Whitney U, and Wilcoxon tests. Results The average absorbed doses, respectively, for the large and small FOVs were 17.19 and 28.89 mGy in the Promax 3D, 19.25 and 35.46 mGy in the NewTom VGi, and 18.85 and 30.63 mGy in the NewTom 5G. The absorbed doses related to the FOVs were not significantly different (P value = 0.1930). However, the effective doses were significantly greater at the smaller FOVs / higher resolutions (P = 0.0039). The doses of the three devices were not significantly different (P = 0.8944). The difference among the nine organs/tissues was significant (Kruskal-Wallis P=0.0000). Conclusion The absorbed doses pertaining to the devices and the FOVs were not significantly different, although the organs/tissues absorbed considerably different doses. PMID:27853498

  7. Value of Computerized Tomography Enterography in Predicting Crohn’s Disease Activity: Correlation with Crohn’s Disease Activity Index and C-Reactive Protein

    PubMed Central

    Park, Eun Kyung; Han, Na Yeon; Park, Beom Jin; Sung, Deuk Jae; Cho, Sung Beom; Jeen, Yoon Tae; Keum, Bora; Kim, Min Ju

    2016-01-01

    Background The accurate evaluation of Crohn’s disease activity is important for the treatment of the disease and for monitoring the response. Computerized tomography (CT) enterography is a useful imaging modality that reflects enteric inflammation, as well as extramural complications. Objectives The aim of this study was to evaluate the correlation between CT enterographic (CTE) findings of active Crohn’s disease and the Crohn’s disease activity index (CDAI) and C-reactive protein (CRP). Patients and Methods Fifty CT enterographies of 39 patients with Crohn’s disease in the small bowel were used in our study. The CDAI was assessed through clinical and laboratory variables. Multiple CT parameters, including mural hyperenhancement, mural thickness, mural stratification, comb sign, and mesenteric fat attenuation, were evaluated with a four-point scale. The presence or absence of enhanced lymph nodes, fibrofatty proliferation, sinus or fistula, abscess, and stricture were also assessed. Two gastrointestinal radiologists independently reviewed all CT images, and inter-observer agreement was examined. Correlations between CT findings, CRP, and CDAI were assessed using Spearman’s rank correlation and logistic regression analysis. To assess the predictive accuracy of the model, a receiver-operating characteristic curve analysis for the sum of CT enterographic scores was used. Results Mural hyperenhancement, mural thickness, comb sign, mesenteric fat density, and fibrofatty proliferation were significantly correlated with CDAI and CRP (P < 0.05). The binary logistic regression model demonstrated that mesenteric fat density, mural stratification, and the presence of enhanced lymph nodes (P < 0.05) had an influence on CDAI severity. The area under the receiver operating characteristic curve (AUROC) of the CTE index for predicting disease activity was 0.85. Using a cut-off value of 8, the sensitivity and negative predictive values were 95% and 94%, respectively

  8. Could spot urine analysis of calcium and uric acid help predict density of urinary stone in computerized tomography? A preliminary study.

    PubMed

    Demiray, Özay; Cüce, Ferhat; Çevik, Erdem; Çataloğlu, Berkay; Kalemci, Serdar

    2016-08-01

    This research studies if Hounsfield density of urinary stone can be predicted without computerized tomography (CT) caused by because increased radiation exposure in follow-up of patients. The records of patients with renal or ureteral stone were analyzed retrospectively for the time period between November 2013 and April 2014. The inclusion criteria defined were: no multiple stones; stone size ≥3 mm; presence of renal and ureteral stones; absence of staghorn stone. All CT images were assessed in abdominal windows by a single radiologist. Hounsfield Unit (HU) value of CT was used to interpret the density of the stone. The density of the stone was measured in the longest axis of the stone center (core) and the edges (periphery) of each stone. Biochemical analysis of spot urine calcium (Ca) and uric acid (UA) was done at the time of diagnosis. Correlation and linear regression analysis was performed. Forty patients were included the study and median age of patients is 22 (IQR 21-28). Since the unit was a military hospital, most patients admitted to hospital were young male conscripts with low median age. It has been found that spot urine uric acid and uric acid/Ca ratio is associated with stone density as HU (P=0.004, P<0.001). Although predictive value appeared low, linear regression model statistically predicted stone density as HU (P<0.001 R2=0.32). Stone size has proved to be positively correlated with stone density (P<0.001). Despite the predictive value of urine analysis model is low, it may be considered to predict HU attenuation of stone. Spot urine analysis of calcium and uric acid may be helpful for both diagnosis and follow-up. We believe that controlled studies with larger patient populations will provide further insights into this issue.

  9. Morphometric evaluation of subaxial cervical spine using multi-detector computerized tomography (MD-CT) scan: the consideration for cervical pedicle screws fixation.

    PubMed

    Chanplakorn, Pongsthorn; Kraiwattanapong, Chaiwat; Aroonjarattham, Kitti; Leelapattana, Pittavat; Keorochana, Gun; Jaovisidha, Suphaneewan; Wajanavisit, Wiwat

    2014-04-11

    Cervical pedicle screw (CPS) insertion is a technically demanding procedure. The quantitative understanding of cervical pedicle morphology, especially the narrowest part of cervical pedicle or isthmus, would minimize the risk of catastrophic damage to surrounding neurovascular structures and improve surgical outcome. The aim of this study was to investigate morphology and quantify cortical thickness of the cervical isthmus by using Multi-detector Computerized Tomography (MD-CT) scan. The cervical CT scans were performed in 74 patients (37 males and 37 females) with 1-mm slice thickness and then retro-reconstructed into sagittal and coronal planes to measure various cervical parameters as follows: outer pedicle width (OPW), inner pedicle width (IPW), outer pedicle height (OPH), inner pedicle height (IPH), pedicle cortical thickness, pedicle sagittal angle (PSA), and pedicle transverse angle (PTA). Total numbers of 740 pedicles were measured in this present study. The mean OPW and IPW significantly increased from C3 to C7 while the mean OPH and IPH of those showed non-significant difference between any measured levels. The medial-lateral cortical thickness was significantly smaller than the superior-inferior one. PTA in the upper cervical spine was significantly wider than the lower ones. The PSA changed from upward inclination at upper cervical spine to the downward inclination at lower cervical spine. This study has demonstrated that cervical vertebra has relatively small and narrow inner pedicle canal with thick outer pedicle cortex and also shows a variable in pedicle width and inconsistent transverse angle. To enhance the safety of CPS insertion, the entry point and trajectories should be determined individually by using preoperative MD-CT scan and the inner pedicle width should be a key parameter to determine the screw dimensions.

  10. Exploring the role of technitium-99m dimercaptosuccinyl acid (V) scan in medullary carcinoma thyroid patients with postoperative persistent hypercalcitoninemia in the era of positron emission tomography-computerized tomography.

    PubMed

    Krishnamurthy, Arvind; Kumar, Ramachandran Krishna; Ravishankaran, Praveen; Ramshankar, Vijayalaksmi; Balkis Begum, Ahamed Sultan; Rangarajan, Gomadam Kuppuswamy

    2014-07-01

    Many radio-pharmaceuticals have been used over the years to localize the recurrences in patients with medullary carcinoma thyroid (MCT), including iodine-131-metaiodobenzylguanidine, thallium-201, technitium-99m dimercaptosuccinyl acid [Tc-99m DMSA (V)], Tc-99m methoxyisobutylisonitril, Tc-99 ethylenediamine diacetic acid/hydrazinonicotinyl-Tyr (3)-octreotide, and In-111 diethylenetriaminepenta-acetic acid-octreotide with varying sensitivities and specificities. The aim of this study is to explore the role of Tc-99m DMSA (V) scan in MCT patients with postoperative persistent hypercalcitoninemia in the positron emission tomography-computerized tomography (PET-CT) era. A retrospective review of 53 patients with proven sporadic MCT, who presented to our institution over a period 28 years from 1985 to 2012, was performed. Patients with persistently elevated levels of serum calcitonin (>150 pg/ml) were initially evaluated by a DMSA scan if conventional imaging failed to localize any focus of disease. Our study showed that the postoperative levels of serum calcitonin significantly correlated with the overall survival of our patients and can possibly serve as a good prognostic marker. Tc-99m DMSA (V) scans demonstrated a sensitivity of 75%, specificity of 56%, a positive predictive value of 50%, and a negative predictive value of 80% in detecting metastasis in postoperative persistent hypercalcitoninemia. Our study showed that Tc-99m DMSA (V) scanning is an affordable and a reasonably sensitive imaging agent for localization of recurrent/metastatic disease. PET-CT seems to be a useful complementary tool and needs to be kept in the armamentarium for diagnosis of recurrence especially in cases of discordance between Tc-99m DMSA (V) scan and the serum calcitonin levels.

  11. Exploring the role of technitium-99m dimercaptosuccinyl acid (V) scan in medullary carcinoma thyroid patients with postoperative persistent hypercalcitoninemia in the era of positron emission tomography-computerized tomography

    PubMed Central

    Krishnamurthy, Arvind; Kumar, Ramachandran Krishna; Ravishankaran, Praveen; Ramshankar, Vijayalaksmi; Balkis Begum, Ahamed Sultan; Rangarajan, Gomadam Kuppuswamy

    2014-01-01

    Background: Many radio-pharmaceuticals have been used over the years to localize the recurrences in patients with medullary carcinoma thyroid (MCT), including iodine-131-metaiodobenzylguanidine, thallium-201, technitium-99m dimercaptosuccinyl acid [Tc-99m DMSA (V)], Tc-99m methoxyisobutylisonitril, Tc-99 ethylenediamine diacetic acid/hydrazinonicotinyl-Tyr (3)-octreotide, and In-111 diethylenetriaminepenta-acetic acid-octreotide with varying sensitivities and specificities. Aims: The aim of this study is to explore the role of Tc-99m DMSA (V) scan in MCT patients with postoperative persistent hypercalcitoninemia in the positron emission tomography-computerized tomography (PET-CT) era. Materials and Methods: A retrospective review of 53 patients with proven sporadic MCT, who presented to our institution over a period 28 years from 1985 to 2012, was performed. Patients with persistently elevated levels of serum calcitonin (>150 pg/ml) were initially evaluated by a DMSA scan if conventional imaging failed to localize any focus of disease. Results and Conclusions: Our study showed that the postoperative levels of serum calcitonin significantly correlated with the overall survival of our patients and can possibly serve as a good prognostic marker. Tc-99m DMSA (V) scans demonstrated a sensitivity of 75%, specificity of 56%, a positive predictive value of 50%, and a negative predictive value of 80% in detecting metastasis in postoperative persistent hypercalcitoninemia. Our study showed that Tc-99m DMSA (V) scanning is an affordable and a reasonably sensitive imaging agent for localization of recurrent/metastatic disease. PET-CT seems to be a useful complementary tool and needs to be kept in the armamentarium for diagnosis of recurrence especially in cases of discordance between Tc-99m DMSA (V) scan and the serum calcitonin levels. PMID:25210279

  12. Single photon emission computed tomography (SPECT) and SPECT/low-dose computerized tomography did not increase sensitivity or specificity compared to planar bone scintigraphy for detection of bone metastases in advanced breast cancer.

    PubMed

    Haraldsen, Ate; Bluhme, Henrik; Røhl, Lisbeth; Pedersen, Erik Morre; Jensen, Anders Bonde; Hansen, Eva Boysen; Nellemann, Hanne; Rasmussen, Finn; Morsing, Anni

    2016-01-01

    To evaluate and compare the diagnostic performance of whole-body planar bone scintigraphy (WBS), single photon emission computed tomography (SPECT), SPECT/low-dose computerized tomography (SPECT/ldCT) and SPECT/contrast enhanced diagnostic CT (SPECT/cdCT) in the staging of patients with advanced breast cancer. Seventy-eight patients with recurrence of biopsy-proven breast cancer and suspicion of disseminated disease were investigated with WBS, SPECT, SPECT/ldCT, SPECT/cdCT and MRI performed on the same day in this prospective study. Images were separately analysed in a blinded fashion by radiologists and nuclear medicine physicians regarding the presence of pathological findings. MRI served as reference standard. According to reference standard, 38 of 73 patients had bone metastases. The sensitivity was 87%, 87%, 79%, and 84% and specificity 63%, 71%, 63% and 83% for WBS, SPECT, SPECT/ldCT and SPECT/cdCT. A significantly increased specificity of SPECT/cdCT compared to WBS and SPECT/ldCT was found, and other parameters did not differ significantly between modalities. Additional two patients had bone metastases solely located outside the MRI scan field and seven patients had soft tissue metastases, but no skeletal changes on MRI. WBS, SPECT and SPECT/ldCT were less sensitive than MRI and equally specific for the detection of bone metastases in patients with advanced breast cancer. Based on our findings, we suggest that initial staging include WBS, MRI of the spine and CT for soft tissue evaluation. Further studies may clarify the potential benefits of whole-body MRI and 18F-NaF PET/CT or 18F-FDG PET/CT. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  13. Comparison of Conventional Radiography and Digital Computerized Radiography in Patients Presenting to Emergency Department.

    PubMed

    Ozcete, Enver; Boydak, Bahar; Ersel, Murat; Kiyan, Selahattin; Uz, Ilhan; Cevrim, Ozgur

    2015-03-01

    To compare the differences between conventional radiography and digital computerized radiography (CR) in patients presenting to the emergency department. The study enrolled consecutive patients presenting to the emergency department who needed chest radiography. Quality score of the radiogram was assessed with visual analogue score (VAS-100 mm), measured in terms of millimeters and recorded at the end of study. Examination time, interpretation time, total time, and cost of radiograms were calculated. There were significant differences between conventional radiography and digital CR groups in terms of location unit (Care Unit, Trauma, Resuscitation), hour of presentation, diagnosis group, examination time, interpretation time, and examination quality. Examination times for conventional radiography and digital CR were 45.2 and 34.2 minutes, respectively. Interpretation times for conventional radiography and digital CR were 25.2 and 39.7 minutes, respectively. Mean radiography quality scores for conventional radiography and digital CR were 69.1 mm and 82.0 mm. Digital CR had a 1.05 TL cheaper cost per radiogram compared to conventional radiography. Since interpretation of digital radiograms is performed via terminals inside the emergency department, the patient has to be left in order to interpret the digital radiograms, which prolongs interpretation times. We think that interpretation of digital radiograms with the help of a mobile device would eliminate these difficulties. Although the initial cost of setup of digital CR and PACS service is high at the emergency department, we think that Digital CR is more cost-effective than conventional radiography for emergency departments in the long-term.

  14. Accuracy of dementia diagnosis: a direct comparison between radiologists and a computerized method.

    PubMed

    Klöppel, Stefan; Stonnington, Cynthia M; Barnes, Josephine; Chen, Frederick; Chu, Carlton; Good, Catriona D; Mader, Irina; Mitchell, L Anne; Patel, Ameet C; Roberts, Catherine C; Fox, Nick C; Jack, Clifford R; Ashburner, John; Frackowiak, Richard S J

    2008-11-01

    There has been recent interest in the application of machine learning techniques to neuroimaging-based diagnosis. These methods promise fully automated, standard PC-based clinical decisions, unbiased by variable radiological expertise. We recently used support vector machines (SVMs) to separate sporadic Alzheimer's disease from normal ageing and from fronto-temporal lobar degeneration (FTLD). In this study, we compare the results to those obtained by radiologists. A binary diagnostic classification was made by six radiologists with different levels of experience on the same scans and information that had been previously analysed with SVM. SVMs correctly classified 95% (sensitivity/specificity: 95/95) of sporadic Alzheimer's disease and controls into their respective groups. Radiologists correctly classified 65-95% (median 89%; sensitivity/specificity: 88/90) of scans. SVM correctly classified another set of sporadic Alzheimer's disease in 93% (sensitivity/specificity: 100/86) of cases, whereas radiologists ranged between 80% and 90% (median 83%; sensitivity/specificity: 80/85). SVMs were better at separating patients with sporadic Alzheimer's disease from those with FTLD (SVM 89%; sensitivity/specificity: 83/95; compared to radiological range from 63% to 83%; median 71%; sensitivity/specificity: 64/76). Radiologists were always accurate when they reported a high degree of diagnostic confidence. The results show that well-trained neuroradiologists classify typical Alzheimer's disease-associated scans comparable to SVMs. However, SVMs require no expert knowledge and trained SVMs can readily be exchanged between centres for use in diagnostic classification. These results are encouraging and indicate a role for computerized diagnostic methods in clinical practice.

  15. Accuracy of dementia diagnosis—a direct comparison between radiologists and a computerized method

    PubMed Central

    Stonnington, Cynthia M.; Barnes, Josephine; Chen, Frederick; Chu, Carlton; Good, Catriona D.; Mader, Irina; Mitchell, L. Anne; Patel, Ameet C.; Roberts, Catherine C.; Fox, Nick C.; Jack, Clifford R.; Ashburner, John; Frackowiak, Richard S. J.

    2008-01-01

    There has been recent interest in the application of machine learning techniques to neuroimaging-based diagnosis. These methods promise fully automated, standard PC-based clinical decisions, unbiased by variable radiological expertise. We recently used support vector machines (SVMs) to separate sporadic Alzheimer's disease from normal ageing and from fronto-temporal lobar degeneration (FTLD). In this study, we compare the results to those obtained by radiologists. A binary diagnostic classification was made by six radiologists with different levels of experience on the same scans and information that had been previously analysed with SVM. SVMs correctly classified 95% (sensitivity/specificity: 95/95) of sporadic Alzheimer's disease and controls into their respective groups. Radiologists correctly classified 65–95% (median 89%; sensitivity/specificity: 88/90) of scans. SVM correctly classified another set of sporadic Alzheimer's disease in 93% (sensitivity/specificity: 100/86) of cases, whereas radiologists ranged between 80% and 90% (median 83%; sensitivity/specificity: 80/85). SVMs were better at separating patients with sporadic Alzheimer's disease from those with FTLD (SVM 89%; sensitivity/specificity: 83/95; compared to radiological range from 63% to 83%; median 71%; sensitivity/specificity: 64/76). Radiologists were always accurate when they reported a high degree of diagnostic confidence. The results show that well-trained neuroradiologists classify typical Alzheimer's disease-associated scans comparable to SVMs. However, SVMs require no expert knowledge and trained SVMs can readily be exchanged between centres for use in diagnostic classification. These results are encouraging and indicate a role for computerized diagnostic methods in clinical practice. PMID:18835868

  16. Computerized prediction of breast cancer risk: comparison between the global and local bilateral mammographic tissue asymmetry

    NASA Astrophysics Data System (ADS)

    Wang, Xingwei; Lederman, Dror; Tan, Jun; Wang, Xiao Hui; Zheng, Bin

    2011-03-01

    We have developed and preliminarily tested a new breast cancer risk prediction model based on computerized bilateral mammographic tissue asymmetry. In this study, we investigated and compared the performance difference of our risk prediction model when the bilateral mammographic tissue asymmetrical features were extracted in two different methods namely (1) the entire breast area and (2) the mirror-matched local strips between the left and right breast. A testing dataset including bilateral craniocaudal (CC) view images of 100 negative and 100 positive cases for developing breast abnormalities or cancer was selected from a large and diverse full-field digital mammography (FFDM) image database. To detect bilateral mammographic tissue asymmetry, a set of 20 initial "global" features were extracted from the entire breast areas of two bilateral mammograms in CC view and their differences were computed. Meanwhile, a pool of 16 local histogram-based statistic features was computed from eight mirror-matched strips between the left and right breast. Using a genetic algorithm (GA) to select optimal features, two artificial neural networks (ANN) were built to predict the risk of a test case developing cancer. Using the leave-one-case-out training and testing method, two GAoptimized ANNs yielded the areas under receiver operating characteristic (ROC) curves of 0.754+/-0.024 (using feature differences extracted from the entire breast area) and 0.726+/-0.026 (using the feature differences extracted from 8 pairs of local strips), respectively. The risk prediction model using either ANN is able to detect 58.3% (35/60) of cancer cases 6 to 18 months earlier at 80% specificity level. This study compared two methods to compute bilateral mammographic tissue asymmetry and demonstrated that bilateral mammographic tissue asymmetry was a useful breast cancer risk indicator with high discriminatory power.

  17. Three-dimensional computer graphics-based ankle morphometry with computerized tomography for total ankle replacement design and positioning.

    PubMed

    Kuo, Chien-Chung; Lu, Hsuan-Lun; Leardini, Alberto; Lu, Tung-Wu; Kuo, Mei-Ying; Hsu, Horng-Chaung

    2014-05-01

    Morphometry of the bones of the ankle joint is important for the design of joint replacements and their surgical implantations. However, very little three-dimensional (3D) data are available and not a single study has addressed the Chinese population. Fifty-eight fresh frozen Chinese cadaveric ankle specimens, 26 females, and 32 males, were CT-scanned in the neutral position and their 3D computer graphics-based models were reconstructed. The 3D morphology of the distal tibia/fibula segment and the full talus was analyzed by measuring 31 parameters, defining the relevant dimensions, areas, and volumes from the models. The measurements were compared statistically between sexes and with previously reported data from Caucasian subjects. The results showed that, within a general similarity of ankle morphology between the current Chinese and previous Caucasian subjects groups, there were significant differences in 9 out of the 31 parameters analyzed. From a quantitative comparison with available prostheses designed for the Caucasian population, few of these designs have both tibial and talar components suitable in dimension for the Chinese population. The current data will be helpful for the sizing, design, and surgical positioning of ankle replacements and for surgical instruments, especially for the Chinese population. Copyright © 2013 Wiley Periodicals, Inc.

  18. Comparison of Automated Scoring Methods for a Computerized Performance Assessment of Clinical Judgment

    ERIC Educational Resources Information Center

    Harik, Polina; Baldwin, Peter; Clauser, Brian

    2013-01-01

    Growing reliance on complex constructed response items has generated considerable interest in automated scoring solutions. Many of these solutions are described in the literature; however, relatively few studies have been published that "compare" automated scoring strategies. Here, comparisons are made among five strategies for…

  19. Comparison of Automated Scoring Methods for a Computerized Performance Assessment of Clinical Judgment

    ERIC Educational Resources Information Center

    Harik, Polina; Baldwin, Peter; Clauser, Brian

    2013-01-01

    Growing reliance on complex constructed response items has generated considerable interest in automated scoring solutions. Many of these solutions are described in the literature; however, relatively few studies have been published that "compare" automated scoring strategies. Here, comparisons are made among five strategies for…

  20. Computerized assessment of body image in anorexia nervosa and bulimia nervosa: comparison with standardized body image assessment tool.

    PubMed

    Caspi, Asaf; Amiaz, Revital; Davidson, Noa; Czerniak, Efrat; Gur, Eitan; Kiryati, Nahum; Harari, Daniel; Furst, Miriam; Stein, Daniel

    2017-02-01

    Body image disturbances are a prominent feature of eating disorders (EDs). Our aim was to test and evaluate a computerized assessment of body image (CABI), to compare the body image disturbances in different ED types, and to assess the factors affecting body image. The body image of 22 individuals undergoing inpatient treatment with restricting anorexia nervosa (AN-R), 22 with binge/purge AN (AN-B/P), 20 with bulimia nervosa (BN), and 41 healthy controls was assessed using the Contour Drawing Rating Scale (CDRS), the CABI, which simulated the participants' self-image in different levels of weight changes, and the Eating Disorder Inventory-2-Body Dissatisfaction (EDI-2-BD) scale. Severity of depression and anxiety was also assessed. Significant differences were found among the three scales assessing body image, although most of their dimensions differentiated between patients with EDs and controls. Our findings support the use of the CABI in the comparison of body image disturbances in patients with EDs vs.

  1. Comparison of total variation algorithms for electrical impedance tomography.

    PubMed

    Zhou, Zhou; Sato dos Santos, Gustavo; Dowrick, Thomas; Avery, James; Sun, Zhaolin; Xu, Hui; Holder, David S

    2015-06-01

    The applications of total variation (TV) algorithms for electrical impedance tomography (EIT) have been investigated. The use of the TV regularisation technique helps to preserve discontinuities in reconstruction, such as the boundaries of perturbations and sharp changes in conductivity, which are unintentionally smoothed by traditional l2 norm regularisation. However, the non-differentiability of TV regularisation has led to the use of different algorithms. Recent advances in TV algorithms such as the primal dual interior point method (PDIPM), the linearised alternating direction method of multipliers (LADMM) and the spilt Bregman (SB) method have all been demonstrated successful EIT applications, but no direct comparison of the techniques has been made. Their noise performance, spatial resolution and convergence rate applied to time difference EIT were studied in simulations on 2D cylindrical meshes with different noise levels, 2D cylindrical tank and 3D anatomically head-shaped phantoms containing vegetable material with complex conductivity. LADMM had the fastest calculation speed but worst resolution due to the exclusion of the second-derivative; PDIPM reconstructed the sharpest change in conductivity but with lower contrast than SB; SB had a faster convergence rate than PDIPM and the lowest image errors.

  2. Massive training artificial neural network (MTANN) for reduction of false positives in computerized detection of lung nodules in low-dose computed tomography.

    PubMed

    Suzuki, Kenji; Armato, Samuel G; Li, Feng; Sone, Shusuke; Doi, Kunio

    2003-07-01

    In this study, we investigated a pattern-recognition technique based on an artificial neural network (ANN), which is called a massive training artificial neural network (MTANN), for reduction of false positives in computerized detection of lung nodules in low-dose computed tomography (CT) images. The MTANN consists of a modified multilayer ANN, which is capable of operating on image data directly. The MTANN is trained by use of a large number of subregions extracted from input images together with the teacher images containing the distribution for the "likelihood of being a nodule." The output image is obtained by scanning an input image with the MTANN. The distinction between a nodule and a non-nodule is made by use of a score which is defined from the output image of the trained MTANN. In order to eliminate various types of non-nodules, we extended the capability of a single MTANN, and developed a multiple MTANN (Multi-MTANN). The Multi-MTANN consists of plural MTANNs that are arranged in parallel. Each MTANN is trained by using the same nodules, but with a different type of non-nodule. Each MTANN acts as an expert for a specific type of non-nodule, e.g., five different MTANNs were trained to distinguish nodules from various-sized vessels; four other MTANNs were applied to eliminate some other opacities. The outputs of the MTANNs were combined by using the logical AND operation such that each of the trained MTANNs eliminated none of the nodules, but removed the specific type of non-nodule with which the MTANN was trained, and thus removed various types of non-nodules. The Multi-MTANN consisting of nine MTANNs was trained with 10 typical nodules and 10 non-nodules representing each of nine different non-nodule types (90 training non-nodules overall) in a training set. The trained Multi-MTANN was applied to the reduction of false positives reported by our current computerized scheme for lung nodule detection based on a database of 63 low-dose CT scans (1765

  3. Fentanyl Iontophoretic Transdermal System (IONSYS(®)) can be Safely used in the Hospital Environment with X-Rays, Computerized Tomography and Radiofrequency Identification Devices.

    PubMed

    Lemke, John; Sardariani, Edmond; Phipps, Joseph Bradley; Patel, Niki; Itri, Loretta M; Caravelli, James; Viscusi, Eugene R

    2016-09-01

    Fentanyl iontophoretic transdermal system (fentanyl ITS, IONSYS(®)) is a patient-controlled analgesia system used for the management of acute postoperative pain, designed to be utilized in a hospital setting. The objective of the two studies was to determine if fentanyl ITS could be safely used with X-rays, computerized tomography (CT) scans and radiofrequency identification (RFID) devices. The ITS system has two components: controller and drug unit; the studies utilized ITS systems without fentanyl, referred to as the ITS Placebo system. The first study evaluated the effect of X-radiation on the operation of an ITS Placebo system. Five ITS Placebo systems were exposed to X-rays (20 and 200 mSv total radiation dose-the 200 mSv radiation dose represents a tenfold higher exposure than in clinical practice) while operating in the Ready Mode and five were exposed while operating in the Dose Mode. The second study evaluated the effect of RFID (worst-case scenario of direct contact with an RFID transmitter) on the operation of an ITS Placebo system. During these tests, observations of the user interface and measurements of output voltage confirmed proper function throughout all operational modes (Ready Mode, Dose Mode, End-of-Use Mode, and End-of-Life Mode). The ITS Placebo system met all specifications and no functional anomalies were observed during and following X-ray exposure at two radiation dose levels or exposure at six different combinations of RFID frequencies and field strengths. The performance of the ITS system was unaffected by X-ray exposure levels well beyond those associated with diagnostic X-rays and CT scans, and by exposure to radiofrequency field strengths typically generated by RFID devices. These results provide added confidence to clinicians that the fentanyl ITS system does not need to be removed during diagnostic X-rays and CT scans and can also be utilized in close proximity to RFID devices. The studies and writing of this manuscript were

  4. A computerized tomography scan method for calculating the hernia sac and abdominal cavity volume in complex large incisional hernia with loss of domain.

    PubMed

    Tanaka, E Y; Yoo, J H; Rodrigues, A J; Utiyama, E M; Birolini, D; Rasslan, S

    2010-02-01

    Preoperative progressive pneumoperitoneum (PPP) is a safe and effective procedure in the treatment of large incisional hernia (size > 10 cm in width or length) with loss of domain (LIHLD). There is no consensus in the literature on the amount of gas that must be insufflated in a PPP program or even how long it should be maintained. We describe a technique for calculating the hernia sac volume (HSV) and abdominal cavity volume (ACV) based on abdominal computerized tomography (ACT) scanning that eliminates the need for subjective criteria for inclusion in a PPP program and shows the amount of gas that must be insufflated into the abdominal cavity in the PPP program. Our technique is indicated for all patients with large or recurrent incisional hernias evaluated by a senior surgeon with suspected LIHLD. We reviewed our experience from 2001 to 2008 of 23 consecutive hernia surgical procedures of LIHLD undergoing preoperative evaluation with CT scanning and PPP. An ACT was required in all patients with suspected LIHLD in order to determine HSV and ACV. The PPP was performed only if the volume ratio HSV/ACV (VR = HSV/ACV) was >or=25% (VR >or= 25%). We have performed this procedure on 23 patients, with a mean age of 55.6 years (range 31-83). There were 16 women and 7 men with an average age of 55.6 years (range 31-83), and a mean BMI of 38.5 kg/m(2) (range 23-55.2). Almost all patients (21 of 23 patients-91.30%) were overweight; 43.5% (10 patients) were severely obese (obese class III). The mean calculated volumes for ACV and HSV were 9,410 ml (range 6,060-19,230 ml) and 4,500 ml (range 1,850-6,600 ml), respectively. The PPP is performed by permanent catheter placed in a minor surgical procedure. The total amount of CO(2) insufflated ranged from 2,000 to 7,000 ml (mean 4,000 ml). Patients required a mean of 10 PPP sessions (range 4-18) to achieve the desired volume of gas (that is the same volume that was calculated for the hernia sac). Since PPP sessions were performed

  5. Injections of Intravenous Contrast for Computerized Tomography Scans Precipitate Migraines in Hereditary Hemorrhagic Telangiectasia Subjects at Risk of Paradoxical Emboli: Implications for Right-to-Left Shunt Risks.

    PubMed

    Patel, Trishan; Elphick, Amy; Jackson, James E; Shovlin, Claire L

    2016-11-01

    To evaluate if injection of intravenous particles may provoke migraines in subjects with right-to-left shunts due to pulmonary arteriovenous malformations (AVMs). Migraine headaches commonly affect people with hereditary hemorrhagic telangiectasia (HHT), especially those with pulmonary AVMs that provide right-to-left shunts. In our clinical practice, patients occasionally reported acute precipitation of migraine headaches following injection of technetium-labeled albumin macroaggregates for nuclear medicine scans. Self-reported migraine features and exacerbations were examined in HHT subjects with and without pulmonary AVMs, for a series of noninvasive and invasive investigations, using an unbiased online survey. One hundred and sixty-six subjects were classified as having both HHT and migraines. HHT subjects with migraines were more likely to have pulmonary AVMs (P < .0001). HHT subjects with pulmonary AVMs were more likely to report photophobia (P = .010), "flashes of light" (P = .011), or transient visual loss (P = .040). Pulse oximetry, x-rays, ultrasound, and computerized tomography (CT) scans without intravenous contrast medium rarely, if ever, provoked migraines, but unenhanced magnetic resonance imaging (MRI) was reported to exacerbate migraines by 14/124 (11.2%) subjects. One hundred and fourteen subjects had both enhanced and unenhanced CT examinations: studies with contrast media were more commonly reported to start (9/114 [7.8%]), and/or worsen migraines (18/114 [15.7%]), compared to those undertaken without contrast medium (P < .01), or after simple blood tests (P < .05). Additionally, migraine exacerbation was reported by 9/90 (10%) after contrast echocardiography, 2/44 (4.5%) after nuclear medicine scans, and 10/154 (6.5%) after blood tests. HHT subjects frequently report migraine exacerbation following blood tests, contrast echocardiograms, MRI imaging, and CT studies performed with intravenous contrast medium. Since air

  6. Injections of Intravenous Contrast for Computerized Tomography Scans Precipitate Migraines in Hereditary Hemorrhagic Telangiectasia Subjects at Risk of Paradoxical Emboli: Implications for Right‐to‐Left Shunt Risks

    PubMed Central

    Patel, Trishan; Elphick, Amy; Jackson, James E.

    2016-01-01

    Objective To evaluate if injection of intravenous particles may provoke migraines in subjects with right‐to‐left shunts due to pulmonary arteriovenous malformations (AVMs). Background Migraine headaches commonly affect people with hereditary hemorrhagic telangiectasia (HHT), especially those with pulmonary AVMs that provide right‐to‐left shunts. In our clinical practice, patients occasionally reported acute precipitation of migraine headaches following injection of technetium‐labeled albumin macroaggregates for nuclear medicine scans. Methods Self‐reported migraine features and exacerbations were examined in HHT subjects with and without pulmonary AVMs, for a series of noninvasive and invasive investigations, using an unbiased online survey. Results One hundred and sixty‐six subjects were classified as having both HHT and migraines. HHT subjects with migraines were more likely to have pulmonary AVMs (P < .0001). HHT subjects with pulmonary AVMs were more likely to report photophobia (P = .010), “flashes of light” (P = .011), or transient visual loss (P = .040). Pulse oximetry, x‐rays, ultrasound, and computerized tomography (CT) scans without intravenous contrast medium rarely, if ever, provoked migraines, but unenhanced magnetic resonance imaging (MRI) was reported to exacerbate migraines by 14/124 (11.2%) subjects. One hundred and fourteen subjects had both enhanced and unenhanced CT examinations: studies with contrast media were more commonly reported to start (9/114 [7.8%]), and/or worsen migraines (18/114 [15.7%]), compared to those undertaken without contrast medium (P < .01), or after simple blood tests (P < .05). Additionally, migraine exacerbation was reported by 9/90 (10%) after contrast echocardiography, 2/44 (4.5%) after nuclear medicine scans, and 10/154 (6.5%) after blood tests. Conclusions HHT subjects frequently report migraine exacerbation following blood tests, contrast echocardiograms, MRI imaging, and

  7. Helical computerized tomography and NT-proBNP for screening of right ventricular overload on admission and at long term follow-up of acute pulmonary embolism

    PubMed Central

    2012-01-01

    Background Right ventricular dysfunction (RVD) in acute pulmonary embolism (APE) can be assessed with helical computerized tomography (CT) and transthoracic echocardiography (TTE). Signs of RVD and elevated natriuretic peptides like NT-proBNP and cardiac troponin (TnT) are associated with increased risk of mortality. However, the prognostic role of both initial diagnostic strategy and the use of NT-proBNP and TnT for screening for long-term probability of RVD remains unknown. The aim of the study was to determine the role of helical CT and NT-proBNP in detection of RVD in the acute phase. In addition, the value of NT-proBNP for ruling out RVD at long-term follow-up was assessed. Methods Sixty-three non-high risk APE patients were studied. RVD was assessed at admission in the emergency department by CT and TTE, and both NT-proBNP and TnT samples were taken. These, excepting CT, were repeated seven months later. Results At admission RVD was detected by CT in 37 (59 %) patients. RVD in CT correlated strongly with RVD in TTE (p < 0.0001). NT-proBNP was elevated (≥ 350 ng/l) in 32 (86 %) patients with RVD but in only seven (27 %) patients without RVD (p < 0.0001). All the patients survived until the 7-month follow-up. TTE showed persistent RVD in 6 of 63 (10 %) patients who all had RVD in CT at admission. All of them had elevated NT-proBNP levels in the follow-up compared with 5 (9 %) of patients without RVD (p < 0.0001). Conclusions TTE does not confer further benefit when helical CT is used for screening for RVD in non-high risk APE. All the patients who were found to have RVD in TTE at seven months follow-up had had RVD in the acute phase CT as well. Thus, patients without RVD in diagnostic CT do not seem to require further routine follow-up to screen for RVD later. On the other hand, persistent RVD and thus need for TTE control can be ruled out by assessment of NT-proBNP at follow-up. A follow-up protocol based on these findings is suggested. PMID:22559861

  8. Computerized Dental Comparison: A Critical Review of Dental Coding and Ranking Algorithms Used in Victim Identification.

    PubMed

    Adams, Bradley J; Aschheim, Kenneth W

    2016-01-01

    Comparison of antemortem and postmortem dental records is a leading method of victim identification, especially for incidents involving a large number of decedents. This process may be expedited with computer software that provides a ranked list of best possible matches. This study provides a comparison of the most commonly used conventional coding and sorting algorithms used in the United States (WinID3) with a simplified coding format that utilizes an optimized sorting algorithm. The simplified system consists of seven basic codes and utilizes an optimized algorithm based largely on the percentage of matches. To perform this research, a large reference database of approximately 50,000 antemortem and postmortem records was created. For most disaster scenarios, the proposed simplified codes, paired with the optimized algorithm, performed better than WinID3 which uses more complex codes. The detailed coding system does show better performance with extremely large numbers of records and/or significant body fragmentation. © 2015 American Academy of Forensic Sciences.

  9. Performance comparison of different metrics for spectroscopic optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Jaedicke, Volker; Agcaer, Semih; Robles, Francisco E.; Steinert, Marian; Jones, David; Goebel, Sebastian; Gerhardt, Nils C.; Welp, Hubert; Hofmann, Martin R.

    2014-03-01

    When light interacts with a scattering medium, the spectrum of the incident light undergoes changes that are dependent on the size of the scatterers in the medium. Spectroscopic Optical Coherence Tomography (S-OCT) is a method that can be used to ascertain the resulting spatially-dependent spectral information. In fact, S-OCT is sensitive to structures that are below the spatial resolution of the system, making S-OCT a promising tool for diagnosing many diseases and biological processes that change tissue structure, like cancer. The most important signal processing steps for S-OCT are the depth-resolved spectral analysis and the calculation of a spectroscopic metric. While the former calculates the spectra from the raw OCT data, the latter analyzes the information content of the processed depth-resolved spectra. We combine the Dual Window spectral analysis with different spectroscopic metrics, which are used as an input to colorize intensity based images. These metrics include the spectral center of mass method, principal component (PCA) and phasor analysis. To compare the performance of the metrics in a quantitative manner, we use a cluster algorithm to calculate efficiencies for all methods. For this purpose we use phantom samples which contain areas of microspheres of different sizes. Our results demonstrate that PCA and phasor analysis have the highest efficiencies, and can clearly separate these areas. Finally we will present data from cartilage tissue under static load in vitro. These preliminary results show that S-OCT can generate additional contrast in biological tissue in comparison to the pure intensity based images.

  10. High-resolution nuclear magnetic resonance imaging and single photon emission computerized tomography--cerebral blood flow in a case of pure sensory stroke and mild dementia owing to subcortical arteriosclerotic encephalopathy (Binswanger's disease)

    SciTech Connect

    De Chiara, S.; Lassen, N.A.; Andersen, A.R.; Gade, A.; Lester, J.; Thomsen, C.; Henriksen, O.

    1987-01-01

    Pure sensory stroke (PSS) is typically caused by a lacunar infarct located in the ventral-posterior (VP) thalamic nucleus contralateral to the paresthetic symptoms. The lesion is usually so small that it cannot be seen on computerized tomography (CT), as illustrated by our case. In our moderately hypertensive, 72-year-old patient with PSS, CT scanning and conventional nuclear magnetic resonance imaging (NMRI) scanning using a 7-mm-thick slice on a 1.5 Tesla instrument all failed to visualize the thalamic infarct. Using the high-resolution mode with 2-mm slice thickness it was, however, clearly seen. In addition, NMRI unexpectedly showed diffuse periventricular demyelinization as well as three other lacunar infarcts, i.e., findings characteristic of subcortical arteriosclerotic encephalopathy (SAE). This prompted psychometric testing, which revealed signs of mild (subclinical) dementia, in particular involving visiospatial apraxia; this pointed to decreased function of the right parietal cortex, which was structurally intact on CT and NMRI. Single photon emission computerized tomography by Xenon-133 injection and by hexamethyl-propyleneamine-oxim labeled with Technetium-99m showed asymmetric distribution of cerebral blood flow (CBF), with an 18% lower value in the right parietal cortex compared to the left side; this indicated asymmetric disconnection of the cortex by the SAE. Thus, the tomograms of the functional parameter, CBF, correlated better with the deficits revealed by neuropsychological testing than by CT or NMRI.

  11. A comparison of validity rates between paper-and-pencil and computerized testing with the MMPI-2.

    PubMed

    Blazek, Nicole L; Forbey, Johnathan D

    2011-03-01

    Although the use of computerized testing in psychopathology assessment has increased in recent years, limited research has examined the impact of this format in terms of potential differences in test validity rates. The current study explores potential differences in the rates of valid and invalid Minnesota Multiphasic Personality Inventory-2 (MMPI-2) protocols between computerized and paper-and-pencil administrations. Participants were 387 undergraduate students (157 men and 230 women) from a Midwestern university who completed either a computerized version or a paper-and-pencil version of the MMPI-2. Chi-square analyses revealed some important differences between administration modalities by gender. Overall, results indicated that although no differences existed in the computerized version, men were more likely to invalidate the paper-and-pencil version. Furthermore, although less likely overall to produce invalid MMPI-2 results, women were more likely to invalidate the paper-and-pencil version via random responding compared with the computerized version. Limitations and future directions are discussed.

  12. Research review: A comparison of levels of job satisfaction between traditional hospital coders and coders using computerized encoders.

    PubMed

    Osborn, C E; Zale, K E

    1996-08-01

    Computerized encoders that assist medical record department coders in making ICD-9-CM disease and operative code selections have been available for approximately 10 years but there have been no studies to evaluate job satisfaction among coders using this technology. The purpose of this study was to determine whether there is a difference in job satisfaction between coders who use computerized encoders and those who do not. The Job Descriptive Index was mailed to hospital medical record departments in Cleveland, Columbus, and Cincinnati, Ohio; the return rate was 93.5 percent. Results indicated that individuals in these three cities coding by the traditional manual method were more satisfied with their jobs than those who used computer technology. The coders in the traditional group were more challenged by their jobs and had more positive interactions with their peers and supervisors. Also traditional coders were satisfied with the pay they received; coders using computerized encoders believed that their pay was inadequate.

  13. Comparison between Dichotomous and Polytomous Scoring of Innovative Items in a Large-Scale Computerized Adaptive Test

    ERIC Educational Resources Information Center

    Jiao, Hong; Liu, Junhui; Haynie, Kathleen; Woo, Ada; Gorham, Jerry

    2012-01-01

    This study explored the impact of partial credit scoring of one type of innovative items (multiple-response items) in a computerized adaptive version of a large-scale licensure pretest and operational test settings. The impacts of partial credit scoring on the estimation of the ability parameters and classification decisions in operational test…

  14. A Comparison of an Expert Systems Approach to Computerized Adaptive Testing and an Item Response Theory Model.

    ERIC Educational Resources Information Center

    Frick, Theodore W.

    Expert systems can be used to aid decisionmaking. A computerized adaptive test is one kind of expert system, although not commonly recognized as such. A new approach, termed EXSPRT, was devised that combines expert systems reasoning and sequential probability ratio test stopping rules. Two versions of EXSPRT were developed, one with random…

  15. Comparison between Dichotomous and Polytomous Scoring of Innovative Items in a Large-Scale Computerized Adaptive Test

    ERIC Educational Resources Information Center

    Jiao, Hong; Liu, Junhui; Haynie, Kathleen; Woo, Ada; Gorham, Jerry

    2012-01-01

    This study explored the impact of partial credit scoring of one type of innovative items (multiple-response items) in a computerized adaptive version of a large-scale licensure pretest and operational test settings. The impacts of partial credit scoring on the estimation of the ability parameters and classification decisions in operational test…

  16. Comparison of Multistage Tests with Computerized Adaptive and Paper-and-Pencil Tests. Research Report. ETS RR-07-04

    ERIC Educational Resources Information Center

    Rotou, Ourania; Patsula, Liane; Steffen, Manfred; Rizavi, Saba

    2007-01-01

    Traditionally, the fixed-length linear paper-and-pencil (P&P) mode of administration has been the standard method of test delivery. With the advancement of technology, however, the popularity of administering tests using adaptive methods like computerized adaptive testing (CAT) and multistage testing (MST) has grown in the field of measurement…

  17. A Comparison of Validity Rates between Paper-and-Pencil and Computerized Testing with the MMPI-2

    ERIC Educational Resources Information Center

    Blazek, Nicole L.; Forbey, Johnathan D.

    2011-01-01

    Although the use of computerized testing in psychopathology assessment has increased in recent years, limited research has examined the impact of this format in terms of potential differences in test validity rates. The current study explores potential differences in the rates of valid and invalid Minnesota Multiphasic Personality Inventory--2…

  18. A Computerized System for the Development, Analysis, and Comparison of Diamond Jubilee and Century 21 Shorthand Dictation Materials.

    ERIC Educational Resources Information Center

    Kavan, C. Bruce; Gallion, Leona M.

    The document describes System 2, a computerized system for analyzing controlled vocabulary material and for comparing the Diamond Jubilee and Century 21 shorthand systems. Background information on three other computer systems for shorthand dictation are briefly described: (1) Reese and Smith Program (University of Tennessee), (2) Kavan and…

  19. Comparison of computed tomography and pluridirectional tomography of the temporal bone

    SciTech Connect

    Lufkin, R.; Barni, J.J.; Glen, W.; Mancuso, A.; Canalis, R.; Hanafee, W.

    1982-06-01

    During pluridirectional tomography dense bone creates ghost shadows that simulate chronic disease and soft-tissue masses within the middle ear cavity. This effect was demonstrated in three dried skulls. Cholesteatomas were simulated in three more temporal bones with a mixture of 2% iodine in paraffin. Three different high-resolution computed tomographic scanners clearly demonstrated middle ear anatomy and the simulated soft-tissue masses in the skulls.

  20. Crossed cerebellar diaschisis in ischemic stroke: a study of regional cerebral blood flow by /sup 133/Xe inhalation and single photon emission computerized tomography

    SciTech Connect

    Meneghetti, G.; Vorstrup, S.; Mickey, B.; Lindewald, H.; Lassen, N.A.

    1984-06-01

    Seventy measurements of CBF were performed in 12 stroke patients by /sup 133/Xe inhalation and a rapidly rotating single photon emission computerized tomograph. CBF was measured every other day during the acute phase and at 2- and 6-month follow-up visits. A persistent contralateral cerebellar blood flow depression was evident in five patients with severe hemispheric low flow areas, which correlated with large, hypodense lesions on the computerized tomographic scan. In a sixth patient with a small, deep infarct, a transient crossed cerebellar low flow was observed, while the clinical symptoms persisted. It is concluded from this serial study that crossed cerebellar diaschisis is a common finding in completed stroke. It is probably caused by disconnection of the corticopontine pathways, a disconnection that tends to persist. The phenomenon is in fact less variable than the stroke-related CBF changes in the infarcted hemisphere, in which a period of relative hyperemia is frequently seen.

  1. Comparison of two image reconstruction algorithms for microwave tomography

    NASA Astrophysics Data System (ADS)

    Fhager, A.; Persson, M.

    2005-06-01

    Two image reconstruction algorithms for microwave tomography are compared and contrasted. One is a general, gradient-based minimization algorithm. The other is the chirp pulse microwave computed tomography (CP-MCT) method, which is a highly computationally efficient reconstruction method but also a method best suited for low contrasts. The results of the simulations show that when imaging high-contrast objects, such as a breast cancer tumor, reconstructions made are comparable to results from the minimization algorithm below a contrast of about 10%. The simulations, however, show that the reconstructions made by the CP-MCT method are very robust to noise. The reconstruction of the conductivity using the minimization algorithm, on the other hand, is very sensitive to the level of noise. In spite of a strong degradation in the conductivity reconstructions, the corresponding permittivity reconstructions do not show the same sensitivity to the noise level.

  2. Comparison of orbital volume obtained by tomography and rapid prototyping.

    PubMed

    Roça, Guilherme Berto; Foggiatto, José Aguiomar; Ono, Maria Cecilia Closs; Ono, Sergio Eiji; da Silva Freitas, Renato

    2013-11-01

    This study aims to compare orbital volume obtained by helical tomography and rapid prototyping. The study sample was composed of 6 helical tomography scans. Eleven healthy orbits were identified to have their volumes measured. The volumetric analysis with the helical tomography utilized the same protocol developed by the Plastic Surgery Unit of the Federal University of Paraná. From the CT images, 11 prototypes were created, and their respective volumes were analyzed in 2 ways: using software by SolidWorks and by direct analysis, when the prototype was filled with saline solution. For statistical analysis, the results of the volumes of the 11 orbits were considered independent. The average orbital volume measurements obtained by the method of Ono et al was 20.51 cm, the average obtained by the SolidWorks program was 20.64 cm, and the average measured using the prototype method was 21.81 cm. The 3 methods demonstrated a strong correlation between the measurements. The right and left orbits of each patient had similar volumes. The tomographic method for the analysis of orbital volume using the Ono protocol yielded consistent values, and by combining this method with rapid prototyping, both reliability validations of results were enhanced.

  3. Comparing non contrast computerized tomography criteria versus dual X-ray absorptiometry as predictors of radio-opaque upper urinary tract stone fragmentation after electromagnetic shockwave lithotripsy.

    PubMed

    Hameed, Diaa A; Elgammal, Mohammed A; ElGanainy, Ehab O; Hageb, Adel; Mohammed, Khaled; El-Taher, Ahmed Mohamed; Mostafa, Mostafa Mohamed; Ahmed, Abdelfatah Ibrahim

    2013-11-01

    The objective of this study was to assess the value of dual X-ray absorptiometry (DXA) in comparison to non contrast computed tomography (NCCT) density as possible predictors of upper urinary tract stone disintegration by shock wave lithotripsy (SWL). This study included 100 consecutive patients, with solitary renal stone 0.5-2 cm or upper ureteral stone up to 1 cm. DXA to calculate stone mineral density (SMD) and stone mineral content (SMC) was done. NCCT was performed to measure Hounsfield units (HU). SWL was performed with an electromagnetic lithotripsy, plain X-ray documented disintegration after SWL. Successful treatment was defined as stone free or complete fragmentation after 1 or 2 sessions of SWL. The impact of patients age, sex, body mass index, stone laterality, location, volume, length, mean SMC and SMD, HU and Hounsfield density (HD), skin to stone distance (SSD) and number of shock waves were evaluated by univariate and multivariate analysis. Only 76 patients were available for follow-up. Success of disintegration was observed in 50 out of 76 patients (65.8 %). On multivariate analysis, SMC and number of shock wave were the significant independent factors affecting SWL outcome (p = 0.04 and p = 0.000, respectively). SMC as detected by DXA is a significant predictor of success of stone disintegration by SWL. SMC measured by DXA is more accurate than HU measured by CT. Patients with high stone mineral content (SMC greater than 0.65 g) should be directly offered another treatment option.

  4. Computerized image analysis as a tool to quantify infiltrating leukocytes: a comparison between high- and low-magnification images.

    PubMed

    Johansson, A C; Visse, E; Widegren, B; Sjögren, H O; Siesjö, P

    2001-09-01

    The purpose of the present study was to establish a rapid and reproducible method for quantification of tissue-infiltrating leukocytes using computerized image analysis. To achieve this, the staining procedure, the image acquisition, and the image analysis method were optimized. Because of the adaptive features of the human eye, computerized image analysis is more sensitive to variations in staining compared with manual image analysis. To minimize variations in staining, an automated immunostainer was used. With a digital scanner camera, low-magnification images could be sampled at high resolution, thus making it possible to analyze larger tissue sections. Image analysis was performed by color thresholding of the digital images based on values of hue, saturation, and intensity color mode, which we consider superior to the red, green, and blue color mode for analysis of most histological stains. To evaluate the method, we compared computerized analysis of images with a x100 or a x12.5 magnification to assess leukocytes infiltrating rat brain tumors after peripheral immunizations with tumor cells genetically modified to express rat interferon-gamma (IFN-gamma) or medium controls. The results generated by both methods correlated well and did not show any significant differences. The method allows efficient and reproducible processing of large tissue sections that is less time-consuming than conventional methods and can be performed with standard equipment and software.(J Histochem Cytochem 49:1073-1079, 2001)

  5. Emission tomography of the kidney

    SciTech Connect

    Teates, C.D.; Croft, B.Y.; Brenbridge, N.A.; Bray, S.T.; Williamson, B.R.

    1983-12-01

    Single photon emission computerized tomography (SPECT) was done on two patients with suspected renal masses. Nuclear scintigraphy was equivocal on two tumors readily identified by SPECT. Single photon tomography is cost effective and increases the reliability of nuclear scintigraphy.

  6. Comparison of Tissue Density in Hounsfield Units in Computed Tomography and Cone Beam Computed Tomography.

    PubMed

    Varshowsaz, Masoud; Goorang, Sepideh; Ehsani, Sara; Azizi, Zeynab; Rahimian, Sepideh

    2016-03-01

    Bone quality and quantity assessment is one of the most important steps in implant treatment planning. Different methods such as computed tomography (CT) and recently suggested cone beam computed tomography (CBCT) with lower radiation dose and less time and cost are used for bone density assessment. This in vitro study aimed to compare the tissue density values in Hounsfield units (HUs) in CBCT and CT scans of different tissue phantoms with two different thicknesses, two different image acquisition settings and in three locations in the phantoms. Four different tissue phantoms namely hard tissue, soft tissue, air and water were scanned by three different CBCT and a CT system in two thicknesses (full and half) and two image acquisition settings (high and low kVp and mA). The images were analyzed at three sites (middle, periphery and intermediate) using eFilm software. The difference in density values was analyzed by ANOVA and correction coefficient test (P<0.05). There was a significant difference between density values in CBCT and CT scans in most situations, and CBCT values were not similar to CT values in any of the phantoms in different thicknesses and acquisition parameters or the three different sites. The correction coefficients confirmed the results. CBCT is not reliable for tissue density assessment. The results were not affected by changes in thickness, acquisition parameters or locations.

  7. Comparison of Tissue Density in Hounsfield Units in Computed Tomography and Cone Beam Computed Tomography

    PubMed Central

    Varshowsaz, Masoud; Goorang, Sepideh; Ehsani, Sara; Azizi, Zeynab; Rahimian, Sepideh

    2016-01-01

    Objectives: Bone quality and quantity assessment is one of the most important steps in implant treatment planning. Different methods such as computed tomography (CT) and recently suggested cone beam computed tomography (CBCT) with lower radiation dose and less time and cost are used for bone density assessment. This in vitro study aimed to compare the tissue density values in Hounsfield units (HUs) in CBCT and CT scans of different tissue phantoms with two different thicknesses, two different image acquisition settings and in three locations in the phantoms. Materials and Methods: Four different tissue phantoms namely hard tissue, soft tissue, air and water were scanned by three different CBCT and a CT system in two thicknesses (full and half) and two image acquisition settings (high and low kVp and mA). The images were analyzed at three sites (middle, periphery and intermediate) using eFilm software. The difference in density values was analyzed by ANOVA and correction coefficient test (P<0.05). Results: There was a significant difference between density values in CBCT and CT scans in most situations, and CBCT values were not similar to CT values in any of the phantoms in different thicknesses and acquisition parameters or the three different sites. The correction coefficients confirmed the results. Conclusions: CBCT is not reliable for tissue density assessment. The results were not affected by changes in thickness, acquisition parameters or locations. PMID:27928239

  8. Transcranial thermoacoustic tomography: a comparison of two imaging algorithms.

    PubMed

    Liu, Zijian; Liu, Lanbo; Xu, Yuan; Wang, Lihong Victory

    2013-02-01

    Thermoacoustic tomography (TAT) is a novel, non-invasive medical imaging technique but has encountered obstacles in imaging through the cranium. In this paper we present two methods for transcranial TAT: Kirchhoff migration (KM) and reverse-time migration (RTM). The two methods' imaging qualities are verified and compared based on both synthetic and experimental data. RTM proves to have better velocity variance and imaging quality, and little noise with spatial aliasing. RTM is a promising approach for achieving transcranial TAT in further studies.

  9. Comparison of double crosshole and fanbeam Lamb wave ultrasonic tomography

    NASA Astrophysics Data System (ADS)

    Hinders, Mark K.; Malyarenko, Eugene V.

    2001-04-01

    Ultrasonic guided waves, Lamb waves, allow large sections of aircraft structures to be rapidly inspected. However, extracting quantitative information from Lamb wave data has always involved highly trained personnel with a detailed knowledge of mechanical waveguide physics. The work discussed here focuses on a variety of different tomographic reconstruction techniques to graphically represent the Lamb wave data in quantitative maps that can be easily interpreted by technicians. Because the velocity of Lamb waves depends on thickness, for example, the traveltimes of the fundamental Lamb modes can be converted into a thickness map of the inspection region. This paper describes two potentially practical implementations of Lamb wave tomographic imaging techniques that can be optimized for in-the-field testing of large-area aircraft structures. Laboratory measurements discussed here demonstrate that Lamb wave tomography using either a ring of transducers with fan beam reconstructions, or a square array of transducers with algebraic reconstruction tomography, is appropriate for detecting flaws in multilayer aircraft materials. The speed and fidelity of the reconstruction algorithms as well as practical considerations for person-portable array-based systems are discussed in this presentation.

  10. Comparison between Long-Menu and Open-Ended Questions in computerized medical assessments. A randomized controlled trial

    PubMed Central

    Rotthoff, Thomas; Baehring, Thomas; Dicken, Hans-Dieter; Fahron, Urte; Richter, Bernd; Fischer, Martin R; Scherbaum, Werner A

    2006-01-01

    Background Long-menu questions (LMQs) are viewed as an alternative method for answering open-ended questions (OEQs) in computerized assessment. So far this question type and its influence on examination scores have not been studied sufficiently. However, the increasing use of computerized assessments will also lead to an increasing use of this question type. Using a summative online key feature (KF) examination we evaluated whether LMQs can be compared with OEQs in regard to the level of difficulty, performance and response times. We also evaluated the content for its suitability for LMQs. Methods We randomized 146 fourth year medical students into two groups. For the purpose of this study we created 7 peer-reviewed KF-cases with a total of 25 questions. All questions had the same content in both groups, but nine questions had a different answer type. Group A answered 9 questions with an LM type, group B with an OE type. In addition to the LM answer, group A could give an OE answer if the appropriate answer was not included in the list. Results The average number of correct answers for LMQs and OEQs showed no significant difference (p = 0.93). Among all 630 LM answers only one correct term (0.32%) was not included in the list of answers. The response time for LMQs did not significantly differ from that of OEQs (p = 0.65). Conclusion LMQs and OEQs do not differ significantly. Compared to standard multiple-choice questions (MCQs), the response time for LMQs and OEQs is longer. This is probably due to the fact that they require active problem solving skills and more practice. LMQs correspond more suitable to Short answer questions (SAQ) then to OEQ and should only be used when the answers can be clearly phrased, using only a few, precise synonyms. LMQs can decrease cueing effects and significantly simplify the scoring in computerized assessment. PMID:17032439

  11. Computed tomography and magnetic resonance imaging comparisons in boxers

    SciTech Connect

    Jordan, B.D. ); Zimmerman, R.D. )

    1990-03-23

    The efficacy of computed tomography (CT) and magnetic resonance imaging (MRI) in identifying traumatic injuries of the brain was compared in a referred population of 21 amateur and professional boxers. Three boxers displayed CT scans with equivocal findings that were verified as artifacts by MRI. Eleven boxers had both CT and MRI scans with normal findings, and 7 boxers had both CT and MRI scans with abnormal findings. There were no instances where abnormalities demonstrated on CT scanning were not detected by MRI. However, some abnormalities detected on MRI were not detected on CT scans. These included a subdural hematoma, white-matter changes, and a focal contusion. Magnetic resonance imaging appears to be the neuroradiodiagnostic test of choice compared with CT.

  12. Noninvasive quantification of the extent of jeopardized myocardium in patients with single-vessel coronary disease by stress thallium-201 single-photon emission computerized rotational tomography

    SciTech Connect

    Prigent, F.; Maddahi, J.; Garcia, E.; Van Train, K.; Friedman, J.; Berman, D.

    1986-03-01

    In 22 patients with single-vessel coronary artery disease and no history of infarction, stress Tl-201 rotational tomography was used to quantify the extent of jeopardized myocardium. The vertical long- and short-axis tomograms were quantified by means of maximum-count circumferential profile analysis. The scintigraphic extent of jeopardized myocardium was expressed as the percentage of profile points falling 2.5 standard deviations below a previously established mean normal profile and was correlated to a quantitatively expressed angiographic extent of jeopardized myocardium. The extent of jeopardized myocardium varied from 1% to 55% by tomography and 8% to 50% by angiography and correlated with an r = 0.79 and a 10% standard error of the estimate. Defect intensity, reflecting the mean depth by which the abnormal points fell below the normal value of greater than or equal to 10%, was 100% specific for a coronary stenosis of greater than or equal to 70%. In conclusion, this study demonstrates that: patients with single-vessel disease have highly variable extents of hypoperfused myocardium defined by Tl-201 tomography and coronary arteriography, there is a fair relationship between angiographic jeopardy score and perfusion defects by Tl-201 tomography during exercise, and Tl-201 tomography may be used to noninvasively determine the extent of hypoperfused myocardium in coronary artery disease.

  13. Use of computerized tests to evaluate psychomotor performance in children with specific learning disabilities in comparison to normal children.

    PubMed

    Taur, Santosh; Karande, Sunil; Saxena, Akriti A; Gogtay, Nithya J; Thatte, Urmila M

    2014-11-01

    Children with specific learning disabilities (SpLD) have an unexplained difficulty in acquiring basic academic skills resulting in a significant discrepancy between their academic potential and achievements. This study was undertaken to compare the performance on a battery of six psychomotor tests of children with SpLD and those without any learning disabilities (controls) using computerized tests. In this study, 25 children with SpLD and 25 controls (matched for age, socio-economic status and medium of instruction) were given three training sessions over one week. Then children were asked to perform on the six computerized psychomotor tests. RESULTS were compared between the two groups. Children with SpLD fared significantly worse on finger tapping test, choice reaction test, digit picture substitution test and card sorting test compared to the controls ( p <0.05). Children with SpLD have impairment of psychomotor skills like attention, sensory-motor coordination and executive functioning. Further research is needed to evaluate if the remedial education plan results in improvement in psychomotor performance of children with SpLD on these selected tests.

  14. Use of computerized tests to evaluate psychomotor performance in children with specific learning disabilities in comparison to normal children

    PubMed Central

    Taur, Santosh; Karande, Sunil; Saxena, Akriti A.; Gogtay, Nithya J.; Thatte, Urmila M.

    2014-01-01

    Background & objectives: Children with specific learning disabilities (SpLD) have an unexplained difficulty in acquiring basic academic skills resulting in a significant discrepancy between their academic potential and achievements. This study was undertaken to compare the performance on a battery of six psychomotor tests of children with SpLD and those without any learning disabilities (controls) using computerized tests. Methods: In this study, 25 children with SpLD and 25 controls (matched for age, socio-economic status and medium of instruction) were given three training sessions over one week. Then children were asked to perform on the six computerized psychomotor tests. Results were compared between the two groups. Results: Children with SpLD fared significantly worse on finger tapping test, choice reaction test, digit picture substitution test and card sorting test compared to the controls (P<0.05). Interpretation & conclusions: Children with SpLD have impairment of psychomotor skills like attention, sensory-motor coordination and executive functioning. Further research is needed to evaluate if the remedial education plan results in improvement in psychomotor performance of children with SpLD on these selected tests. PMID:25579146

  15. Comparison of gamma-densitometry tomography and electrical-impedance tomography for determining material distribution in liquid-solid flows

    SciTech Connect

    Shollenberger, K.A.; Torczynski, J.R.; O`Hern, T.J.; Adkins, D.R.; Ceccio, S.L.; George, D.L.

    1997-03-01

    The spatial distribution of materials in multiphase flows is of importance to many industrial processes. For example, in indirect coal liquefaction, a reactive gas is bubbled through a catalyst-laden liquid (slurry), and a spatially nonuniform gas distribution can reduce process efficiency by inducing large-scale buoyancy-driven recirculating flows. Gamma-densitometry tomography (GDT) and electrical-impedance tomography (EIT) are techniques with the potential of providing spatially resolved information on material distribution in multiphase flows. GDT and EIT have both been applied to a liquid-solid flow for comparison purposes. The experiment consisted of a cylinder (19 cm diameter) filled with water, in which 80 {micro}m glass spheres were suspended by a mixer to achieve solid volume fractions of 0.01, 0.02, and 0.03. Both GDT and EIT revealed a relatively uniform distribution of solids in the measurement plane, and the average solid volume fractions from both techniques were in good agreement.

  16. A comparison of computed tomography practice in 1989 and 1991.

    PubMed

    Crawley, M T; Rogers, A T

    1994-09-01

    In December 1991, the National Radiological Protection Board (NRPB) published the results of national surveys of the frequency, quality assurance and dosimetric aspects of computed tomography (CT) examinations carried out in hospitals in the UK in 1989. A study of the patient records at two of the original participating hospitals was undertaken to establish whether there had been any change in CT practice between the years 1989 and 1991. Aspects of examination frequency, age distribution and dose were analysed. The results showed significant variations in the patient age distributions between the sub-population studied and the larger sample used by the NRPB, and between the patient age distribution for CT examinations in the years 1989 and 1991 at the two hospitals in this study. The results also showed that in one hospital, where magnetic resonance imaging (MRI) was available and where dose reduction measures had been implemented, there was a net decrease in the collective effective dose from 1989 to 1991, whilst at the other hospital, where MRI was not available and where the introduction of dose saving strategies had been delayed, there was a substantial increase in the collective effective dose from 1989 to 1991. The possibility of continuing increases in the annual collective effective dose attributable to CT underlines the importance of local CT audit to ensure that CT doses are as low as reasonably achievable.

  17. Solitary pulmonary metastases in high-risk melanoma patients: a prospective comparison of conventional and computed tomography

    SciTech Connect

    Heaston, D.K.; Putman, C.E.; Rodan, B.A.; Nicholson, E.; Ravin, C.E.; Korobkin, M.; Chen, J.T.; Seigler, H.F.

    1983-07-01

    A prospective comparison of chest radiography, conventional tomography, and computed tomography (CT) in the detection or confirmation of solitary pulmonary nodules was made in 42 patients with high propensity for pulmonary metastases due to advanced local (Clark level IV or V) or regional malignant melanoma. Unequivocal nodules were revealed by chest radiography in 11 patients, conventional tomograhy in 16, and computed tomography in 20 patients. Both plain films and tomography in three of these 20 were normal, but follow-up verified pulmonary metastases. Computed tomography detected more pulmonary nodules than conventional tomography in 11 patients in addition to identifying lesions in extrapulmonary sites. Therefore, chest CT is recommended before institution of immunotherapy or surgical removal of a solitary pulmonary melanoma metastasis. Once chemotherapy had been instituted for bulky regional or cutaneous involvement, however, the findings of either conventional or computed tomography were comparable in this study.

  18. Bone comparison identification method based on chest computed tomography imaging.

    PubMed

    Matsunobu, Yusuke; Morishita, Junji; Usumoto, Yosuke; Okumura, Miki; Ikeda, Noriaki

    2017-08-31

    The aim of this study is to examine the usefulness of bone structure extracted data from chest computed tomography (CT) images for personal identification. Eighteen autopsied cases (12 male and 6 female) that had ante- and post-mortem (AM and PM) CT images were used in this study. The two-dimensional (2D) and three-dimensional (3D) bone images were extracted from the chest CT images via thresholding technique. The similarity between two thoracic bone images (consisting of vertebrae, ribs, and sternum) acquired from AMCT and PMCT images was calculated in terms of the normalized cross-correlation value (NCCV) in both 2D and 3D matchings. An AM case with the highest NCCV corresponding to a given PM case among all of the AM cases studied was regarded as same person. The accuracy of identification of the same person using our method was 100% (18/18) in both 2D and 3D matchings. The NCCVs for the same person tended to be significantly higher than the average of NCCVs for different people in both 2D and 3D matchings. The computation times of image similarity between the two images were less than one second and approximately 10min in 2D and 3D matching, respectively. Therefore, 2D matching especially for thoracic bones seems more advantageous than 3D matching with regard to computation time. We conclude that our proposed personal identification method using bone structure would be useful in forensic cases. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Comparison of denture models by means of micro computed tomography

    NASA Astrophysics Data System (ADS)

    Vögtlin, Christoph; Schulz, Georg; Deyhle, Hans; Jäger, Kurt; Liebrich, Thomas; Weikert, Sascha; Müller, Bert

    2012-10-01

    The production of dental inlays and crowns requires precise information on patients' teeth morphology. The conventional method is the preparation of impressions using mold materials, e.g. a silicone impression material. The disadvantage of this technique is the human choke impulse and the flavor of the material. These discomforts can be avoided by methods where a three-dimensional scanner is used for recording the teeth morphology. The present study reveals the accuracy of three model types, namely conventional impression, rapid prototyping using an oral scanner C.O.S., 3M (Schweiz) AG and milling from a proprietary resin using the oral scanner iTero, Straumann Holding AG. For each method five models were fabricated from a steel reference (standard). Using a nanotom m (phoenixǀx-ray, GE Sensing and Inspection Technologies GmbH), three-dimensional micro computed tomography data sets of the standard and the 15 models were recorded and landmark distances within the data sets were measured with sub-pixel accuracy. To verify these results a coordinate measuring machine (Leitz PMM 864, Hexagon Metrology GmbH) based on tactile detection was used for the measurement of the landmark distances, and a correction of the distances measured by the nanotom m was arranged. The nanotom data sets of the 15 models were also compared to the standard by means of a non-rigid registration algorithm. The calculated deformation field exhibited mean pixel displacement values of (0.19 +/- 0.09) mm for the C.O.S. models, (0.12 +/- 0.07) mm for the gypsum models and (0.19 +/- 0.12) mm for the i-Tero models.

  20. Comparison of computed tomography scout based reference point localization to conventional film and axial computed tomography.

    PubMed

    Jiang, Lan; Templeton, Alistair; Turian, Julius; Kirk, Michael; Zusag, Thomas; Chu, James C H

    2011-01-01

    Identification of source positions after implantation is an important step in brachytherapy planning. Reconstruction is traditionally performed from films taken by conventional simulators, but these are gradually being replaced in the clinic by computed tomography (CT) simulators. The present study explored the use of a scout image-based reconstruction algorithm that replaces the use of traditional film, while exhibiting low sensitivity to metal-induced artifacts that can appear in 3D CT methods. In addition, the accuracy of an in-house graphical software implementation of scout-based reconstruction was compared with seed location reconstructions for 2 phantoms by conventional simulator and CT measurements. One phantom was constructed using a planar fixed grid of 1.5-mm diameter ball bearings (BBs) with 40-mm spacing. The second was a Fletcher-Suit applicator embedded in Styrofoam (Dow Chemical Co., Midland, MI) with one 3.2-mm-diameter BB inserted into each of 6 surrounding holes. Conventional simulator, kilovoltage CT (kVCT), megavoltage CT, and scout-based methods were evaluated by their ability to calculate the distance between seeds (40 mm for the fixed grid, 30-120 mm in Fletcher-Suit). All methods were able to reconstruct the fixed grid distances with an average deviation of <1%. The worst single deviations (approximately 6%) were exhibited in the 2 volumetric CT methods. In the Fletcher-Suit phantom, the intermodality agreement was within approximately 3%, with the conventional sim measuring marginally larger distances, with kVCT the smallest. All of the established reconstruction methods exhibited similar abilities to detect the distances between BBs. The 3D CT-based methods, with lower axial resolution, showed more variation, particularly with the smaller BBs. With a software implementation, scout-based reconstruction is an appealing approach because it simplifies data acquisition over film-based reconstruction without requiring any specialized equipment

  1. Comparison of deferral rates using a computerized versus written blood donor questionnaire: a randomized, cross-over study [ISRCTN84429599

    PubMed Central

    Sellors, John W; Hayward, Robert; Swanson, Graham; Ali, Anita; Haynes, R Brian; Bourque, Ronald; Moore, Karen-Ann; Lohfeld, Lynne; Dalby, Dawn; Howard, Michelle

    2002-01-01

    Background Self-administered computer-assisted blood donor screening strategies may elicit more accurate responses and improve the screening process. Methods Randomized crossover trial comparing responses to questions on a computerized hand-held tool (HealthQuiz, or HQ), to responses on the standard written instrument (Donor Health Assessment Questionnaire, or DHAQ). Randomly selected donors at 133 blood donation clinics in the area of Hamilton, Canada participated from 1995 to 1996. Donors were randomized to complete either the HQ or the DHAQ first, followed by the other instrument. In addition to responses of 'yes' and 'no' on both questionnaires, the HQ provided a response option of 'not sure'. The primary outcome was the number of additional donors deferred by the HQ. Results A total of 1239 donors participated. Seventy-one potential donors were deferred as a result of responses to the questionnaires; 56.3% (40/71) were deferred by the DHAQ, and an additional 43.7% (31/71) were deferred due to risks identified by the HQ but not by the DHAQ. Fourteen donors self-deferred; 11 indicated on the HQ that they should not donate blood on that day but did not use the confidential self-exclusion option on the DHAQ, and three used the self-exclusion option on the DHAQ but did not indicate that they should not donate blood on the HQ. The HQ identified a blood contact or risk factor for HIV/AIDS or sexually transmitted infection that was not identified by the DHAQ in 0.1% to 2.7% of donors. Conclusion A self-administered computerized questionnaire may increase risk reporting by blood donors. PMID:12191432

  2. Quantitative comparison of analysis methods for spectroscopic optical coherence tomography: reply to comment

    PubMed Central

    Bosschaart, Nienke; van Leeuwen, Ton G.; Aalders, Maurice C.G.; Faber, Dirk J.

    2014-01-01

    We reply to the comment by Kraszewski et al on “Quantitative comparison of analysis methods for spectroscopic optical coherence tomography.” We present additional simulations evaluating the proposed window function. We conclude that our simulations show good qualitative agreement with the results of Kraszewski, in support of their conclusion that SOCT optimization should include window shape, next to choice of window size and analysis algorithm. PMID:25401016

  3. Research on ionospheric tomography based on variable pixel height

    NASA Astrophysics Data System (ADS)

    Zheng, Dunyong; Li, Peiqing; He, Jie; Hu, Wusheng; Li, Chaokui

    2016-05-01

    A novel ionospheric tomography technique based on variable pixel height was developed for the tomographic reconstruction of the ionospheric electron density distribution. The method considers the height of each pixel as an unknown variable, which is retrieved during the inversion process together with the electron density values. In contrast to conventional computerized ionospheric tomography (CIT), which parameterizes the model with a fixed pixel height, the variable-pixel-height computerized ionospheric tomography (VHCIT) model applies a disturbance to the height of each pixel. In comparison with conventional CIT models, the VHCIT technique achieved superior results in a numerical simulation. A careful validation of the reliability and superiority of VHCIT was performed. According to the results of the statistical analysis of the average root mean square errors, the proposed model offers an improvement by 15% compared with conventional CIT models.

  4. (18)F-fluorodeoxyglucose positron emission tomography/computed tomography comparison of gastric lymphoma and gastric carcinoma.

    PubMed

    Li, Xiao-Feng; Fu, Qiang; Dong, You-Wen; Liu, Jian-Jing; Song, Xiu-Yu; Dai, Dong; Zuo, Cong; Xu, Wen-Gui

    2016-09-14

    To compare (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) features in gastric lymphoma and gastric carcinoma. Patients with newly diagnosed gastric lymphoma or gastric carcinoma who underwent (18)F-FDG PET/CT prior to treatment were included in this study. We reviewed and analyzed the PET/CT features of gastric wall lesions, including FDG avidity, pattern (focal/diffuse), and intensity [maximal standard uptake value: (SUVmax)]. The correlation of SUVmax with gastric clinicopathological variables was investigated by χ(2) test, and receiver-operating characteristic (ROC) curve analysis was performed to determine the differential diagnostic value of SUVmax-associated parameters in gastric lymphoma and gastric carcinoma. Fifty-two patients with gastric lymphoma and 73 with gastric carcinoma were included in this study. Abnormal gastric FDG accumulation was found in 49 patients (94.23%) with gastric lymphoma and 65 patients (89.04%) with gastric carcinoma. Gastric lymphoma patients predominantly presented with type I and type II lesions, whereas gastric carcinoma patients mainly had type III lesions. The SUVmax (13.39 ± 9.24 vs 8.35 ± 5.80, P < 0.001) and SUVmax/THKmax (maximal thickness) (7.96 ± 4.02 vs 4.88 ± 3.32, P < 0.001) were both higher in patients with gastric lymphoma compared with gastric carcinoma. ROC curve analysis suggested a better performance of SUVmax/THKmax in the evaluation of gastric lesions between gastric lymphoma and gastric carcinoma in comparison with that of SUVmax alone. PET/CT features differ between gastric lymphoma and carcinoma, which can improve PET/CT evaluation of gastric wall lesions and help differentiate gastric lymphoma from gastric carcinoma.

  5. 18F-fluorodeoxyglucose positron emission tomography/computed tomography comparison of gastric lymphoma and gastric carcinoma

    PubMed Central

    Li, Xiao-Feng; Fu, Qiang; Dong, You-Wen; Liu, Jian-Jing; Song, Xiu-Yu; Dai, Dong; Zuo, Cong; Xu, Wen-Gui

    2016-01-01

    AIM To compare 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) features in gastric lymphoma and gastric carcinoma. METHODS Patients with newly diagnosed gastric lymphoma or gastric carcinoma who underwent 18F-FDG PET/CT prior to treatment were included in this study. We reviewed and analyzed the PET/CT features of gastric wall lesions, including FDG avidity, pattern (focal/diffuse), and intensity [maximal standard uptake value: (SUVmax)]. The correlation of SUVmax with gastric clinicopathological variables was investigated by χ2 test, and receiver-operating characteristic (ROC) curve analysis was performed to determine the differential diagnostic value of SUVmax-associated parameters in gastric lymphoma and gastric carcinoma. RESULTS Fifty-two patients with gastric lymphoma and 73 with gastric carcinoma were included in this study. Abnormal gastric FDG accumulation was found in 49 patients (94.23%) with gastric lymphoma and 65 patients (89.04%) with gastric carcinoma. Gastric lymphoma patients predominantly presented with type I and type II lesions, whereas gastric carcinoma patients mainly had type III lesions. The SUVmax (13.39 ± 9.24 vs 8.35 ± 5.80, P < 0.001) and SUVmax/THKmax (maximal thickness) (7.96 ± 4.02 vs 4.88 ± 3.32, P < 0.001) were both higher in patients with gastric lymphoma compared with gastric carcinoma. ROC curve analysis suggested a better performance of SUVmax/THKmax in the evaluation of gastric lesions between gastric lymphoma and gastric carcinoma in comparison with that of SUVmax alone. CONCLUSION PET/CT features differ between gastric lymphoma and carcinoma, which can improve PET/CT evaluation of gastric wall lesions and help differentiate gastric lymphoma from gastric carcinoma. PMID:27678362

  6. Comparison of computerized image analysis with traditional semiquantitative scoring of Perls' Prussian Blue stained hepatic iron deposition.

    PubMed

    Hall, A Peter; Davies, Wendy; Stamp, Katie; Clamp, Isabel; Bigley, Alison

    2013-01-01

    Image analysis is now routinely employed as a tool in toxicologic pathology to help quantitate end points of efficacy and safety. It is regarded as a proficient and a sensitive technique to generate numerical data that can be easily interrogated for statistical evaluation. Traditional semiquantitative pathology scoring on the other hand is sometimes regarded as less accurate due to the limitations of the scoring systems employed and the day-to-day variations often noted between pathologists. We therefore decided to generate an optimized histochemical staining and image analysis protocol to compare the accuracy of semiquantitative scoring with computerized image analysis. In order to achieve this, we describe a standardized protocol for staining and image analysis that eliminates or minimizes as many sources of error as possible. The results of this experiment demonstrate that despite consistent variations in scoring between two independent pathologists, correlation with image analysis data of 0.91 to 0.95 (Spearman's Rho test) was achieved. These data indicate that either image analysis or traditional semiquantitative scoring can generate accurate data. As a result of this, it appears that it is equally safe to employ either method dependent upon the complexity and the practicality of the task at hand provided that the experimental conditions are rigorously optimized and rigidly adhered to.

  7. Pain Experience and Behavior Management in Pediatric Dentistry: A Comparison between Traditional Local Anesthesia and the Wand Computerized Delivery System.

    PubMed

    Garret-Bernardin, Annelyse; Cantile, Tiziana; D'Antò, Vincenzo; Galanakis, Alexandros; Fauxpoint, Gabriel; Ferrazzano, Gianmaria Fabrizio; De Rosa, Sara; Vallogini, Giulia; Romeo, Umberto; Galeotti, Angela

    2017-01-01

    Aim. To evaluate the pain experience and behavior during dental injection, using the Wand computerized delivery system versus conventional local anesthesia in children and adolescents. Methods. An observational crossover split mouth study was performed on 67 patients (aged 7 to 15 years), requiring local anesthesia for dental treatments in both sides of the dental arch. Patients received both types of injections in two separate appointments, one with the use of a Computer Delivery System (the Wand STA system) and one with the traditional syringe. The following data were recorded: pain rating; changes in heart rate; level of collaboration; patient satisfaction. The data were analyzed using ANOVA for quantitative outcomes and nonparametric analysis (Kruskal-Wallis) for qualitative parameters. Results. The use of the Wand system determined significantly lower pain ratings and lower increase of heart rate than the traditional syringe. During injection, the number of patients showing a relaxed behavior was higher with the Wand than with the traditional local anesthesia. The patient level of satisfaction was higher with the Wand compared to the conventional local anesthesia. Conclusions. The Wand system may provide a less painful injection when compared to the conventional local anesthesia and it seemed to be better tolerated with respect to a traditional syringe.

  8. Pain Experience and Behavior Management in Pediatric Dentistry: A Comparison between Traditional Local Anesthesia and the Wand Computerized Delivery System

    PubMed Central

    D'Antò, Vincenzo; Fauxpoint, Gabriel; De Rosa, Sara; Vallogini, Giulia

    2017-01-01

    Aim. To evaluate the pain experience and behavior during dental injection, using the Wand computerized delivery system versus conventional local anesthesia in children and adolescents. Methods. An observational crossover split mouth study was performed on 67 patients (aged 7 to 15 years), requiring local anesthesia for dental treatments in both sides of the dental arch. Patients received both types of injections in two separate appointments, one with the use of a Computer Delivery System (the Wand STA system) and one with the traditional syringe. The following data were recorded: pain rating; changes in heart rate; level of collaboration; patient satisfaction. The data were analyzed using ANOVA for quantitative outcomes and nonparametric analysis (Kruskal–Wallis) for qualitative parameters. Results. The use of the Wand system determined significantly lower pain ratings and lower increase of heart rate than the traditional syringe. During injection, the number of patients showing a relaxed behavior was higher with the Wand than with the traditional local anesthesia. The patient level of satisfaction was higher with the Wand compared to the conventional local anesthesia. Conclusions. The Wand system may provide a less painful injection when compared to the conventional local anesthesia and it seemed to be better tolerated with respect to a traditional syringe. PMID:28293129

  9. A comparison of computerized dynamic posturography therapy to standard balance physical therapy in individuals with Parkinson's disease: a pilot study.

    PubMed

    Qutubuddin, Abu A; Cifu, David X; Armistead-Jehle, Patrick; Carne, William; McGuirk, Theresa E; Baron, Mark S

    2007-01-01

    Postural instability is a common impairment in idiopathic Parkinson's disease (PD). People with PD are prone to balance and walking difficulties. This study analyzed the feasibility of a prospective investigation of Computerized Dynamic Posturography (CDP) and standard Physical Therapy (PT) treatments in individuals with mild-moderate PD. Treatment took place at two sites: 1) CDP therapy at the Southeast Parkinson's Disease Research Education and Clinical Center (PADRECC) within a Veterans Affairs Medical Center and 2) standard physical therapy at a community outpatient rehabilitation center. Final analysis compared 15 patients randomly assigned for therapy to either the CDP or PT treatments. Therapy time was eight weeks (four weeks of CPD or PT followed by home therapy for four weeks). The CDP therapy included gradually intensified closed chain and mobility training. Standard PT consisted of upright, mat, and theraball exercises and gait training. The home exercise phase was identical for both groups. The pilot data demonstrated treatment was tolerated by 68 percent of the sample despite the occurrence of a progressive neurological condition and medical comorbidities. While results failed to reveal any differences between treatment groups, both groups demonstrated improvement on selected outcome measures. An expanded prospective study with methodological improvements appears warranted.

  10. Use of Cone-Beam Computerized Tomography for Evaluation of Bisphosphonate-Associated Osteonecrosis of the Jaws in an Experimental Rat Model

    PubMed Central

    Cankaya, Abdulkadir Burak; Erdem, Mehmet Ali; Isler, Sabri Cemil; Demircan, Sabit; Soluk, Merva; Kasapoglu, Cetin; Oral, Cuneyt Korhan

    2011-01-01

    Background: Bisphosphonate-induced osteonecrosis of the jaw (BONJ) is a frequently reported complication. The aim of this study was to investigate the clinical and histopathological presentation of BONJ with the Hounsfield score and to evaluate the reliability of the score for determining necrosis in an animal model. Material/Methods: Eighty rats were prospectively and randomly divided into two groups of 40 each: a control group and an experimental group. Half of the animals from each group underwent extraction of the left mandibular molars, and the other half underwent extraction of the left maxillary molars under pentobarbital-induced general anesthesia. All animals were euthanized 28 days after tooth extraction. Maxillae and mandibles were extracted, cone beam computed tomography (CBCT) was performed, and Hounsfield scores were evaluated. Results: The Hounsfield scores of the experimental group were found to be compatible with chronic osteomyelitis and periosteal reactions. The Hounsfield scores of the control group were compatible with a healthy healing period. Conclusion: In light of these results, both cone beam computed tomography (CBCT) and the Hounsfield Units (HU) evaluations together are thought to be efficient in the diagnosis of BONJ. PMID:22135613

  11. Assessment of radiation exposure in dental cone-beam computerized tomography with the use of metal-oxide semiconductor field-effect transistor (MOSFET) dosimeters and Monte Carlo simulations.

    PubMed

    Koivisto, J; Kiljunen, T; Tapiovaara, M; Wolff, J; Kortesniemi, M

    2012-09-01

    The aims of this study were to assess the organ and effective dose (International Commission on Radiological Protection (ICRP) 103) resulting from dental cone-beam computerized tomography (CBCT) imaging using a novel metal-oxide semiconductor field-effect transistor (MOSFET) dosimeter device, and to assess the reliability of the MOSFET measurements by comparing the results with Monte Carlo PCXMC simulations. Organ dose measurements were performed using 20 MOSFET dosimeters that were embedded in the 8 most radiosensitive organs in the maxillofacial and neck area. The dose-area product (DAP) values attained from CBCT scans were used for PCXMC simulations. The acquired MOSFET doses were then compared with the Monte Carlo simulations. The effective dose measurements using MOSFET dosimeters yielded, using 0.5-cm steps, a value of 153 μSv and the PCXMC simulations resulted in a value of 136 μSv. The MOSFET dosimeters placed in a head phantom gave results similar to Monte Carlo simulations. Minor vertical changes in the positioning of the phantom had a substantial affect on the overall effective dose. Therefore, the MOSFET dosimeters constitute a feasible method for dose assessment of CBCT units in the maxillofacial region. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. [Study of the musculoskeletal system of the spine in humans after long-term space flights by the method of computerized tomography].

    PubMed

    Oganov, V S; Cann, C; Rakhmanov, A S; Ternovoĭ, S K

    1990-01-01

    By computer tomography, mineral density of lumbar vertebrae and their segments as well as back muscle (++ilio-costal, extensor and ++inter-spinal) density and mass were measured in four Salyut-7 crewmembers before and after extended flights (of 5 and 7 months in duration). These findings are in good agreement with the results of prolonged bed rest studies in which trabecular bone of vertebral bodies was investigated: mineral density diminished only in some (approximately 10%) of the test subjects. At the same time mineral density loss was seen in the vertebral elements where muscles were attached. Also, muscle mass was reduced. It is emphasized that the level of changes was not correlated with flight time. Further investigations in this area are discussed.

  13. [Contrast-free helical computerized tomography compared with ultrasonography and simple abdominal radiography in the study of patients with acute lumbar pain].

    PubMed

    Llopis Cartagena, M; Rams García, A; Fuster Escrivá, A; Díaz Concepción, J; Solaz Mínguez, J; Martín Fernández, H; Gómez Salinas, L

    2001-10-01

    Evaluation the diagnostic ability of unenhanced helical computed tomography in the evaluation of patients with acute flank pain. Prospectively evaluation of 82 patients referred for acute flank pain between january 1999 and june 2000. 78 patients were imaged with, 73 abdominal ultrasound and 46 with TCHNC. Plain radiography shows 49.1% of diagnosed lithiasis. Ultrasound was 48% sensitive and 96% specific. TCHNC was 100% sensitive and 84% specific in the diagnosis of lithiasis, allowing in 11 patients a diagnosis unrelated to stone disease. TCHNC is a valuable radiologic technique for patients presenting with acute flank pain and consider the TCHNC as initial evaluation technique in patients with acute flank pain, allowing not only the localization of the stone as well as the diagnosis of extraurinary pathologies.

  14. Computerized and Paper-and-Pencil Versions of the Rosenberg Self-Esteem Scale: A Comparison of Psychometric Features and Respondent Preferences.

    ERIC Educational Resources Information Center

    Vispoel, Walter P.; Boo, Jaeyool; Bleiler, Timothy

    2001-01-01

    Evaluated the characteristics of computerized and paper-and-pencil versions of the Rosenberg Self-Esteem Scale (SES) using scores for 224 college students. Results show that mode of administration has little effect on the psychometric properties of the SES although the computerized version took longer and was preferred by examinees. (SLD)

  15. Computerized and Paper-and-Pencil Versions of the Rosenberg Self-Esteem Scale: A Comparison of Psychometric Features and Respondent Preferences.

    ERIC Educational Resources Information Center

    Vispoel, Walter P.; Boo, Jaeyool; Bleiler, Timothy

    2001-01-01

    Evaluated the characteristics of computerized and paper-and-pencil versions of the Rosenberg Self-Esteem Scale (SES) using scores for 224 college students. Results show that mode of administration has little effect on the psychometric properties of the SES although the computerized version took longer and was preferred by examinees. (SLD)

  16. Predictive value of excretory urography, ultrasonography, computerized tomography, and liver and bone scan in the staging of bilharzial bladder cancer in Saudi Arabia

    SciTech Connect

    Hanash, K.A.; Bissada, N.K.; Abla, A.; Esmail, D.; Dowling, A.

    1984-07-01

    The role of ultrasonography, computed tomography (CT), and radioisotopic scanning in the staging of bilharzial bladder cancer has not been reported previously. Forty patients with invasive bladder cancer seen at the King Faisal Specialist Hospital and Research Centre between January 1978 and June 1981 underwent complete preoperative workup for staging of their tumors prior to radical cystectomy. The preoperative radiologic investigations included excretory urography (IVP), ultrasonography (US), CT of the pelvis, and liver and bone scans. The results of these investigations were compared with the operative and pathologic staging. Ninety-three percent of the patients with bilharzial cancer had evidence of ureteric obstruction on IVP compared with 22% of the nonbilharzial cancer patients. The presence of ureteric obstruction in these patients did not correlate with the stage of the disease with 83% of the patients with superficial tumors (T1 and T2) having hydroureteronephrosis. Ultrasonography and CT had an 83% accuracy in the staging of superficial tumors. Stage T3 tumors were understaged in 14% of the cases. Ultrasonography did not differentiate Stages T3 and T4 tumors while CT scan differentiated these two stages in 57% of the cases. Bone scan failed to reveal evidence of metastatic disease in any of the bilharzial cancer patients. Liver scan was suspicious for liver metastases in two patients with bilharzial cancers in whom open liver biopsy revealed only hepatic bilharziasis. Of all the radiographic studies, US or preferably CT scan seem to be of some value in the staging of bilharzial tumors localized to the bladder. Bone and liver scans are probably of no cost effective benefit.

  17. A general framework and review of scatter correction methods in x-ray cone-beam computerized tomography. Part 1: Scatter compensation approaches.

    PubMed

    Rührnschopf, Ernst-Peter; Klingenbeck, Klaus

    2011-07-01

    Since scattered radiation in cone-beam volume CT implies severe degradation of CT images by quantification errors, artifacts, and noise increase, scatter suppression is one of the main issues related to image quality in CBCT imaging. The aim of this review is to structurize the variety of scatter suppression methods, to analyze the common structure, and to develop a general framework for scatter correction procedures. In general, scatter suppression combines hardware techniques of scatter rejection and software methods of scatter correction. The authors emphasize that scatter correction procedures consist of the main components scatter estimation (by measurement or mathematical modeling) and scatter compensation (deterministic or statistical methods). The framework comprises most scatter correction approaches and its validity also goes beyond transmission CT. Before the advent of cone-beam CT, a lot of papers on scatter correction approaches in x-ray radiography, mammography, emission tomography, and in Megavolt CT had been published. The opportunity to avail from research in those other fields of medical imaging has not yet been sufficiently exploited. Therefore additional references are included when ever it seems pertinent. Scatter estimation and scatter compensation are typically intertwined in iterative procedures. It makes sense to recognize iterative approaches in the light of the concept of self-consistency. The importance of incorporating scatter compensation approaches into a statistical framework for noise minimization has to be underscored. Signal and noise propagation analysis is presented. A main result is the preservation of differential-signal-to-noise-ratio (dSNR) in CT projection data by ideal scatter correction. The objective of scatter compensation methods is the restoration of quantitative accuracy and a balance between low-contrast restoration and noise reduction. In a synopsis section, the different deterministic and statistical methods are

  18. Technetium-99m dimercaptosuccinic acid scan in evaluation of renal cortical scarring: Is it mandatory to do single photon emission computerized tomography?

    PubMed Central

    Saleh Farghaly, Hussein Rabie; Mohamed Sayed, Mohamed Hosny

    2015-01-01

    Objectives: Renal cortical scintigraphy with technetium-99m (Tc-99m) dimercaptosuccinic acid (DMSA) is the method of choice to detect acute pyelonephritis and cortical scarring. Different acquisition methods have been used: Planar parallel-hole or pinhole collimation and single photon emission tomography (SPECT). This study compared planar parallel-hole cortical scintigraphy and dual-head SPECT for detection of cortical defects. Patients and Methods: We retrospectively reviewed 190 consecutive patients with 380 kidneys and 200 DMSA scans referred to rule out renal cortical scarring. The diagnoses were 52 vesicoureteric reflux, 61 recurrent urinary tract infection, 39 hydronephrosis, 20 renal impairment, and 18 hypertension. All patients were imaged 3 h after injection of Tc-99m DMSA with SPECT and planar imaging (posterior, anterior, left, and right posterior oblique views). For each patient, planar and SPECT images were evaluated at different sittings, in random order. Each kidney was divided into three cortical segments (upper, middle and lower) and was scored as normal or reduced uptake. The linear correlation coefficient for the number of abnormal segments detected between planner and SPECT techniques was calculated. Results: From 200 DMSA scans, 100 scans were positive for scar in SPECT images, from which only 95 scans were positive for scar in planner imaging. Out of the five mismatched scans, three scans were for patients with renal impairment and high background activity and two scans were for very small scars. No significant difference was seen in the average number of abnormal segments detected by planar versus SPECT imaging (P = 0.31). The average correlation coefficient between was high (r = 0.91 – 0.92). Conclusions: Tc-99m DMSA renal cortical scanning using SPECT offers no statistically significant diagnostic advantage over multiple views planar imaging for detection of cortical defect. PMID:25589802

  19. Association of Neutrophil-to-Lymphocyte Ratio with the Severity and Morphology of Coronary Atherosclerotic Plaques Detected by Multidetector Computerized Tomography

    PubMed Central

    Ateş, Ahmet Hakan; Aytemir, Kudret; Koçyiğit, Duygu; Yalcin, Muhammed Ulvi; Gürses, Kadri Murat; Yorgun, Hikmet; Canpolat, Uğur; Hazırolan, Tuncay; Özer, Necla

    2016-01-01

    Background Studies have demonstrated a consistent relationship between white blood cell (WBC) counts and coronary artery disease (CAD). The neutrophil/lymphocyte ratio (NLR) has been considered as a potential marker for identifying individuals under risk of CAD and associated events. In this study, we aimed to evaluate whether NLR was associated with the severity and morphology of coronary atherosclerotic plaques shown by multidetector computed tomography (MDCT). Methods Our study population consisted of 684 patients who underwent dual-source 64 slice MDCT for the assessment of CAD. Coronary arteries were evaluated on a 16-segment basis and critical coronary plaque was described as luminal narrowing > 50%, whereas plaque morphology was assessed on a per segment basis. Total WBC, neutrophil and lymphocyte counts were determined using commercially available assay kits. Results WBC count [7700 (6400-8800) vs. 6800 (5700-7900), p < 0.05] and NLR [2.40 (1.98-3.07) vs. 1.86 (1.50-2.38), p < 0.001] were found to be higher in patients with critical stenosis than in those without. In the binary logistic regression analysis, NLR was a predictor of critical stenosis (odds ratio, 1.68; 95% confidence interval, 1.39-2.03, p < 0.001). NLR levels differed among plaque morphology subtypes (p < 0.05) and was significantly higher in non-calcified plaque (NCP) compared to mixed plaque (MP) and calcified plaque (CP) (p < 0.05). In the multinomial logistic regression analysis, NLR was found to be an independent predictor of NCP, MP and CP (p < 0.001). Conclusions These data show that NLR is associated with both the severity and morphology of coronary atherosclerotic disease. PMID:27899854

  20. A comparison of computerized adaptive testing and fixed-length short forms for the Prosthetic Limb Users Survey of Mobility (PLUS-M(TM)).

    PubMed

    Amtmann, Dagmar; Bamer, Alyssa M; Kim, Jiseon; Bocell, Fraser; Chung, Hyewon; Park, Ryoungsun; Salem, Rana; Hafner, Brian J

    2017-09-01

    New health status instruments can be administered by computerized adaptive test or short forms. The Prosthetic Limb Users Survey of Mobility (PLUS-M(TM)) is a self-report measure of mobility for prosthesis users with lower limb loss. This study used the PLUS-M to examine advantages and disadvantages of computerized adaptive test and short forms. To compare scores obtained from computerized adaptive test to scores obtained from fixed-length short forms (7-item and 12-item) in order to provide guidance to researchers and clinicians on how to select the best form of administration for different uses. Cross-sectional, observational study. Individuals with lower limb loss completed the PLUS-M by computerized adaptive test and short forms. Administration time, correlations between the scores, and standard errors were compared. Scores and standard errors from the computerized adaptive test, 7-item short form, and 12-item short form were highly correlated and all forms of administration were efficient. Computerized adaptive test required less time to administer than either paper or electronic short forms; however, time savings were minimal compared to the 7-item short form. Results indicate that the PLUS-M computerized adaptive test is most efficient, and differences in scores between administration methods are minimal. The main advantage of the computerized adaptive test was more reliable scores at higher levels of mobility compared to short forms. Clinical relevance Health-related item banks, like the Prosthetic Limb Users Survey of Mobility (PLUS-M(TM)), can be administered by computerized adaptive testing (CAT) or as fixed-length short forms (SFs). Results of this study will help clinicians and researchers decide whether they should invest in a CAT administration system or whether SFs are more appropriate.

  1. Effectiveness and acceptability of a computerized decision support system using modified Wells criteria for evaluation of suspected pulmonary embolism.

    PubMed

    Drescher, Frank S; Chandrika, Sharad; Weir, Ian D; Weintraub, Jeffrey T; Berman, Lewis; Lee, Ronald; Van Buskirk, Patricia D; Wang, Yun; Adewunmi, Adeshola; Fine, Jonathan M

    2011-06-01

    Ready availability of computed tomography (CT) angiography for evaluation of pulmonary embolism in emergency departments (EDs) is associated with a dramatic increase in the number of CT angiography tests. The aims of this study are to determine whether a validated prediction algorithm embedded in a computerized decision support system improves the positive yield rate of CT angiography for pulmonary embolism and is acceptable to emergency physicians. This study was conducted as a prospective interventional study with a retrospective preinterventional comparison group. The implementation of the computerized physician order entry-based computerized decision support system was associated with an overall increase in the positivity rate of from 8.3% (95% confidence interval [CI] 4.9% to 12.9%) preintervention to 12.7% (95% CI 8.6% to 17.7%) postintervention, with a difference of 4.4% (95% CI -1.4% to 10.1%). A total of 404 patients were eligible for inclusion. Physician nonadherence to the computerized decision support system occurred in 105 (26.7%) cases. Fifteen patients underwent CT angiography despite low Wells score and negative D-dimer result, all of whose results were negative for pulmonary embolism. Emergency physicians did not order CT angiography for 44 patients despite high pretest probability, with one receiving a diagnosis of pulmonary embolism on a subsequent visit and another, of DVT. When emergency physicians adhered to the computerized decision support system for the evaluation of suspected pulmonary embolism, a higher yield of CT angiography for pulmonary embolism occurred, with 28 positive results of 168 CT angiography tests (16.7%; 95% CI 11.4% to 23.2%) and a difference compared with preintervention of 8.4% (95% CI 1.7% to 15.4%). Physicians cited the time required to apply the computerized decision support system and a preference for intuitive judgment as reasons for not adhering to the computerized decision support system. Use of an evidence

  2. Diagnosis of simulated condylar bone defects using panoramic radiography, spiral tomography and cone-beam computed tomography: A comparison study

    PubMed Central

    Salemi, Fatemeh; Shokri, Abbas; Baharvand, Maryam

    2015-01-01

    Objectives: Radiographic examination is one of the most important parts of the clinical assessment routine for temporomandibular disorders. The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography(CBCT) with panoramic radiography and spiral computed tomography for the detection of the simulated mandibular condyle bone lesions. Study Design: The sample consisted of 10 TMJs from 5 dried human skulls. Simulated erosive and osteophytic lesions were created in 3 different sizes using round diamond bur and bone chips, respectively. Panoramic radiography, spiral tomography and cone-beam computed tomography were used in defect detection. Data were statistically analyzed with the Mann-Whitney test. The reliability and degrees of agreement between two observers were also determined by the mean of Cohen’s Kappa analysis. Results: CBCT had a statistically significant superiority than other studied techniques in detection of both erosive and osteophytic lesions with different sizes. There were significant differences between tomography and panoramic in correct detection of both erosive and osteophytic lesions with 1mm and 1.5 mm in size. However, there were no significant differences between Tomography and Panoramic in correct detection of both erosive and osteophytic lesions with 0.5 mm in size. Conclusions: CBCT images provide a greater diagnostic accuracy than spiral tomography and panoramic radiography in the detection of condylar bone erosions and osteophytes. Key words:Bone defect, Condyle, CBCT, Panoramic, radiography. PMID:25810839

  3. Use of computerized tomography and chest x-rays in evaluating efficacy of aerosolized recombinant human DNase in cystic fibrosis patients younger than age 5 years: a preliminary study.

    PubMed

    Nasr, S Z; Kuhns, L R; Brown, R W; Hurwitz, M E; Sanders, G M; Strouse, P J

    2001-05-01

    The aim of this study was to evaluate the ability of high-resolution computerized tomography (HRCT) of the chest and chest x-rays (CXR) to determine efficacy of inhaled recombinant human DNase (rhDNase) in cystic fibrosis (CF) patients younger than 5 years of age. A randomized, double-blind, placebo-controlled pilot study of 12 patients with CF younger than 5 years of age, attending the University of Michigan Cystic Fibrosis Center (Ann Arbor, MI) was conducted. The changes in the HRCT and CXR score from baseline to day 100 of therapy were assessed using a previously validated scoring system. The mean changes of HRCT scores between the rhDNase and placebo groups were found to be significant at the 95% level, with mean change +/- SE mean of - 1.00 +/- 0.53 and 0.58 +/- 0.24 for rhDNase and placebo groups, respectively (P = 0.02). The difference in CXR score was not significant between the two groups. An analysis was performed to relate HRCT subscores to CXR score; only thickening of the intra-interlobular septae was significantly correlated with the total CXR score (r = - 0.7, P < 0.01). There was improvement in the parents' assessments of the patients' well-being, with improvement in physical activity, decreased cough, sleep quality, and appetite in those subjects receiving rhDNase. We conclude that the administration of rhDNase was associated with improvement in the HRCT scan in CF patients younger than 5 years of age. Findings indicate that HRCT of the chest is useful and sensitive in studying responses to therapy in patients with CF lung disease. To our knowledge, this is the first report of the use of HRCT to assess the effectiveness of a therapeutic modality in so young a CF patient population.

  4. Imaging-based assessment of the mineral composition of urinary stones: an in vitro study of the combination of hounsfield unit measurement in noncontrast helical computerized tomography and the twinkling artifact in color Doppler ultrasound.

    PubMed

    Hassani, Hakim; Raynal, Gauthier; Spie, Romain; Daudon, Michel; Vallée, Jean-Noël

    2012-05-01

    We evaluated the value of combining noncontrast helical computerized tomography (NCHCT) and color Doppler ultrasound in the assessment of the composition of urinary stones. In vitro, we studied 120 stones of known composition, that separate into the five main types: 18 calcium oxalate monohydrate (COM) stones, 41 calcium oxalate dihydrate (COD) stones, 24 uric acid stones, 25 calcium phosphate stones and 12 cystine calculi. Stones were characterized in terms of their Hounsfield density (HU) in NCHCT and the presence of a twinkling artifact (TA) in color Doppler ultrasound. There were statistically significant HU differences between calcium and non-calcium stones (p < 0.001), calcium oxalate stones and calcium phosphate stones (p < 0.001) and uric acid stones and cystine calculi (p < 0.001) but not between COM and COD stones (p = 0.786). Hence, the HU was a predictive factor of the composition of all types of stones, other than for COM and COD stones within the calcium oxalate class (p > 0.05). We found that the TA does not enable differentiation between calcium and non-calcium stones (p > 0.999), calcium oxalate stones and calcium phosphate stones (p = 0.15), or uric acid stones and cystine calculi (p = 0.079). However, it did reveal a significant difference between COM and COD stones (p = 0.002). The absence of a TA is a predictive factor for the presence of COM stones (p = 0.008). Hence, the association of NCHCT and Doppler enables the accurate classification of the five types of stones in vitro.

  5. Three-dimensional finite element analysis of fixed complete-arch prostheses supported by 4 immediate-loaded implants in the completely edentulous maxilla using clinical computerized tomography data.

    PubMed

    Kimura, Katsuhiko; Fukase, Yasumasa; Makino, Michiko; Masaki, Chihiro; Nakamoto, Tetsuji; Hosokawa, Ryuji

    2011-03-01

    Mechanical simulation by loading an occlusal force (load), assumed to be that loaded under clinical conditions, was performed in a computerized tomography (CT) data-based immediate-loaded implant placement simulation. Stresses on and displacements of the implants and surrounding bone tissue were analyzed mechanically using 3-dimensional finite element analysis (FEA). The purpose of this study was to investigate the possibility of practical preoperative design and its evaluation and to assess the effects of connected fixation. Implants with a diameter of 4.0 mm were placed in the bilateral upper incisor and second premolar regions in a 69-year-old woman. An X-ray CT of the head was carried out, and implant placement simulation and 3-dimensional FEA models were constructed from the CT data. Forces were loaded on 4 individual implants placed in this model or all connected implants, and a mechanical analysis was performed. A 100-N vertical force was loaded on each implant as individual loading for the control group, and a 400-N vertical force was loaded on the connected implants as connected loading for the test group. The displacement and stress distributions were assessed using the 3-dimensional FEA. In the test group, established on the assumption of connected fixation for provisional restoration facilitating immediate loading, the maximum stress and displacement of peri-implant bone were smaller than those in the control group undergoing individual loading. The implant displacement level was suggested to serve as a numerical prognostic index of osseointegration of immediate-loaded implants. This method was shown to be immediately applicable to implant placement simulations using CT data currently generated in clinical practice, with no modification. Such a mechanical assessment using the FEA model can be performed noninvasively.

  6. A new computerized ionosphere tomography model using the mapping function and an application to the study of seismic-ionosphere disturbance

    NASA Astrophysics Data System (ADS)

    Kong, Jian; Yao, Yibin; Liu, Lei; Zhai, Changzhi; Wang, Zemin

    2016-08-01

    A new algorithm for ionosphere tomography using the mapping function is proposed in this paper. First, the new solution splits the integration process into four layers along the observation ray, and then, the single-layer model (SLM) is applied to each integration part using a mapping function. Next, the model parameters are estimated layer by layer with the Kalman filtering method by introducing the scale factor (SF) γ to solve the ill-posed problem. Finally, the inversed images of different layers are combined into the final CIT image. We utilized simulated data from 23 IGS GPS stations around Europe to verify the estimation accuracy of the new algorithm; the results show that the new CIT model has better accuracy than the SLM in dense data areas and the CIT residuals are more closely grouped. The stability of the new algorithm is discussed by analyzing model accuracy under different error levels (the max errors are 5TECU, 10TECU, 15TECU, respectively). In addition, the key preset parameter, SFγ , which is given by the International Reference Ionosphere model (IRI2012). The experiment is designed to test the sensitivity of the new algorithm to SF variations. The results show that the IRI2012 is capable of providing initial SF values. Also in this paper, the seismic-ionosphere disturbance (SID) of the 2011 Japan earthquake is studied using the new CIT algorithm. Combined with the TEC time sequence of Sat.15, we find that the SID occurrence time and reaction area are highly related to the main shock time and epicenter. According to CIT images, there is a clear vertical electron density upward movement (from the 150-km layer to the 450-km layer) during this SID event; however, the peak value areas in the different layers were different, which means that the horizontal movement velocity is not consistent among the layers. The potential physical triggering mechanism is also discussed in this paper. Compared with the SLM, the RMS of the new CIT model is improved by

  7. [Integrated role of computerized tomography and magnetic resonance imaging in identifying the early changes in rheumatoid arthritis of the craniocervical junction].

    PubMed

    Di Gregorio, F; Priolo, F; Cerase, A; Belli, P; Galossi, A; Magarò, M; Marano, P

    1997-01-01

    Any cervical spine segment may be affected by rheumatoid arthritis, but destructive changes are most prominent at the craniocervical junction. Cervical involvement is a devastating complication of the disease, because of the risk of a range of neurological complications (paresthesia, cervical myelopathy, vertebro-basilar insufficiency), and even sudden death from medullary compression. However, the incidence of both cervical rheumatoid arthritis and its neurological complications are still debated, being respectively reported in 17-86% and 11-70% of the patients, according to the variability in neurological and radiologic classification systems adopted by the authors. To assess the incidence of cervical rheumatoid arthritis and the integrated role of different imaging techniques in its diagnosis, 38 consecutive patients (29 women and 9 men) with rheumatoid arthritis according to the American Rheumatism Association criteria were examined. The average age was 60 years (range: 27-70 years) with a mean disease duration of 6.6 years (range: 6 months-25 years). All the patients underwent conventional radiography of the cervical spine, unenhanced Computed Tomography (CT) of the craniocervical junction and unenhanced and Gadolinium-enhanced Magnetic Resonance Imaging (MRI) of the cervical spine. Cervical spine involvement was demonstrated in 25/38 (66%) patients 20 women and 5 men, with an average age of 57 years and a mean disease duration of 8.5 years. In 13 of them (mean disease duration: 12.7 years), the diagnosis was made with radiography which showed atlantoaxial and subaxial subluxations and/or erosions. Of the 12 patients with negative conventional radiography (mean disease duration: 2.5 years), 4 were identified with both CT and MRI (synovial pannus and erosions). 3 with MRI only (joint effusion/hypervascularized synovial pannus), and 5 exhibited questionable CT findings which were clarified only by MR demonstration of inflammatory tissue contiguous to suspicious

  8. The combined evaluation of interim contrast-enhanced computerized tomography (CT) and FDG-PET/CT predicts the clinical outcomes and may impact on the therapeutic plans in patients with aggressive non-Hodgkin's lymphoma.

    PubMed

    Yang, Deok-Hwan; Min, Jung-Joon; Jeong, Yong Yeon; Ahn, Jae-Sook; Kim, Yeo-Kyeoung; Cho, Sang-Hee; Chung, Ik-Joo; Bom, Hee-Seung; Kim, Hyeoung-Joon; Lee, Je-Jung

    2009-05-01

    We investigated the concomitant interim response of patients with aggressive non-Hodgkin's lymphoma (NHL) using multi-detector row computerized tomography (CT) and (18)F-fluoro-2-deoxy-D: -glucose-positron emission tomography (PET)/CT for prediction of clinical outcomes. One hundred six newly diagnosed patients with aggressive NHL were enrolled. Both the CT and PET/CT were serially performed at the time of diagnosis and after three to four cycles of chemotherapy (interim). The patients were categorized into four different responsive groups according to the interim PET/CT and CT: (1) complete metabolic response (CMR)-complete response unconfirmed (CRu), (2) CMR-partial response (PR), (3) partial metabolic response (PMR)-Cru, and (4) PMR-PR. Fifty-five patients with CMR-CRu, 20 patients with CMR-PR, seven patients with PMR-Cru, and 23 patients with PMR-PR were distributed. In addition, one patient experienced a disease progression. There was a significant difference in relapse rates between PET/CT-positive (67.3%) and PET/CT-negative patients (17.3%; P < 0.01). Also, there was a significant difference between patients with PMR-PR (32.0% and 26.1%) and CMR-CRu (89.3% and 80.0%) for 3-year overall survival (OS) and event-free survival (EFS), respectively. A multivariate analysis revealed that high international prognostic index (> or =3) at diagnosis, T-cell phenotype, and PMR-PR in interim PET/CT and CT were independent prognostic significances for OS. Moreover, bulky disease (>10 cm), T-cell phenotype, and PMR-PR showed significant associations for EFS. PMR-PR in interim response was the predictive prognostic determinant for both OS and EFS, with a hazard ratio of 3.93 (1.61-9.60) and 3.60 (1.62-7.98), respectively. The combined evaluation of interim PET/CT and CT was found to be a significant predictor of disease progression, OS, and EFS.

  9. Computerized Interpretation of Pulmonary Function — A Comparison of Interpretations by Computer and Physician Using Agreed Criteria

    PubMed Central

    Warshaw, Raphael; Balmes, John; Jung, Ralph; Chong, Sung Chul; Kilburn, Kaye H.

    1984-01-01

    The reference values and interpretive levels used at Barlow Occupational Health Center were incorporated in a computer program and printouts of values and percent predicted were obtained for 65 subjects. A panel of three physicians independently interpreted the studies using the agreed (computer) criteria. Major interpretive differences between physician and computer were: Physician A - 1/65, physician B - 10/65 and physician C - 10/65. For intra-physician comparisons physician A was consistent in 19 of 20, physician B in 16 of 20 and physician C in 9 of 20 cases.

  10. Comparison of approaches based on optimization and algebraic iteration for binary tomography

    NASA Astrophysics Data System (ADS)

    Cai, Weiwei; Ma, Lin

    2010-12-01

    Binary tomography represents a special category of tomographic problems, in which only two values are possible for the sought image pixels. The binary nature of the problems can potentially lead to a significant reduction in the number of view angles required for a satisfactory reconstruction, thusly enabling many interesting applications. However, the limited view angles result in a severely underdetermined system of equations, which is challenging to solve. Various approaches have been proposed to address such a challenge, and two categories of approaches include those based on optimization and those based on algebraic iteration. However, the relative strengths, limitations, and applicable ranges of these approaches have not been clearly defined in the past. Therefore, it is the main objective of this work to conduct a systematic comparison of approaches from each category. This comparison suggested that the approaches based on algebraic iteration offered both superior reconstruction fidelity and computation efficiency at low (two or three) view angles, and these advantages diminished at high view angles. Meanwhile, this work also investigated the application of regularization techniques, the selection of optimal regularization parameter, and the use of a local search technique for binary problems. We expect the results and conclusions reported in this work to provide valuable guidance for the design and development of algorithms for binary tomography problems.

  11. A dosimetric comparison of two high-dose-rate brachytherapy planning systems in cervix cancer: standardized template planning vs. computerized treatment planning.

    PubMed

    Patone, Hassisen; Souhami, Luis; Parker, William; Evans, Michael; Duclos, Marie; Portelance, Lorraine

    2008-01-01

    High-dose-rate brachytherapy is an important component of the curative treatment for cervical cancer. Some institutions use standardized template planning (STP), based on a precalculated table of dose rates, instead of computerized treatment planning (CTP), based on digitized orthogonal X-ray films. STP can be used as a backup check in case of computer hardware malfunction, and/or as a way to minimize treatment planning time. We performed a dosimetric comparison of STP and CTP to determine dose differences at point A and the International Commission on Radiation Units and Measurements Report 38 bladder and rectal reference points. We retrospectively reviewed the treatment plans of 62 patients (135 applications) treated with a tandem and two ovoids using the CTP method. For each of these plans, we calculated the dwell times required to deliver the same prescription dose had STP been used. We also used the planning computer to vary tandem and ovoid geometry and develop a table of dose rates based on geometric parameters. The mean dose at point A was 7.6 Gy using CTP, increasing to 8.4 Gy when the STP approach was used (p<0.05). The mean doses at the International Commission on Radiation Units and Measurements Report 38 bladder and rectal points were both 4.5 Gy with CTP and increased to 4.9 and 5.0 Gy, respectively using STP (p<0.05). Our table of dose rates showed significant dose rate dependency on the applicators geometry. Our study shows that if the STP approach had been used, a significantly higher dose would have been delivered, and that STP tables accounting for differences in implant geometry should be carefully considered.

  12. A comparison of cognitive bias modification for interpretation and computerized cognitive behavior therapy: effects on anxiety, depression, attentional control, and interpretive bias.

    PubMed

    Bowler, Jennifer O; Mackintosh, Bundy; Dunn, Barnaby D; Mathews, Andrew; Dalgleish, Tim; Hoppitt, Laura

    2012-12-01

    Computerized cognitive behavioral therapy (cCBT) and cognitive bias modification for interpretation (CBM-I) both have demonstrated efficacy in alleviating social anxiety, but how they compare with each other has not been investigated. The present study tested the prediction that both interventions would reduce anxiety relative to a no-intervention comparison condition, but CBM-I would be particularly effective at modifying threat-related cognitive bias under high mental load. Sixty-three primarily Caucasian adults (mean age = 22.7, SD = 5.87; 68.3% female) with high social anxiety, randomly allocated to 3 groups: CBM-I (n = 21), cCBT (n = 21), and a no-intervention control group (n = 21) provided complete data for analysis. Pre- and postintervention (4 sessions lasting 2 weeks, control participants only attended the pre-post sessions) self-report measures of anxiety, depression, attentional control, and threat-related interpretive bias were completed. In addition, interpretive bias under high versus low cognitive load was measured using the Scrambled Sentences Test. Both CBM-I and cCBT groups reported significantly reduced levels of social anxiety, trait anxiety, and depression and improved attentional control, relative to the control group, with no clear superiority of either active intervention. Although both active conditions reduced negative bias on the Scrambled Sentences Test completed under mental load, CBM-I was significantly more effective at doing so. The results suggest that although not differing in therapeutic efficacy, CBM-I and cCBT might differ in the resilience of their effects when under mental load.

  13. Volumetric analysis of subarachnoid hemorrhage: assessment of the reliability of two computerized methods and their comparison with other radiographic scales.

    PubMed

    Jiménez-Roldán, Luis; Alén, Jose F; Gómez, Pedro A; Lobato, Ramiro D; Ramos, Ana; Munarriz, Pablo M; Lagares, Alfonso

    2013-01-01

    There were two main purposes to this study: first, to assess the feasibility and reliability of 2 quantitative methods to assess bleeding volume in patients who suffered spontaneous subarachnoid hemorrhage (SAH), and second, to compare these methods to other qualitative and semiquantitative scales in terms of reliability and accuracy in predicting delayed cerebral ischemia (DCI) and outcome. A prospective series of 150 patients consecutively admitted to the Hospital 12 de Octubre over a 4-year period were included in the study. All of these patients had a diagnosis of SAH, and diagnostic CT was able to be performed in the first 24 hours after the onset of the symptoms. All CT scans were evaluated by 2 independent observers in a blinded fashion, using 2 different quantitative methods to estimate the aneurysmal bleeding volume: region of interest (ROI) volume and the Cavalieri method. The images were also graded using the Fisher scale, modified Fisher scale, Claasen scale, and the semiquantitative Hijdra scale. Weighted κ coefficients were calculated for assessing the interobserver reliability of qualitative scales and the Hijdra scores. For assessing the intermethod and interrater reliability of volumetric measurements, intraclass correlation coefficients (ICCs) were used as well as the methodology proposed by Bland and Altman. Finally, weighted κ coefficients were calculated for the different quartiles of the volumetric measurements to make comparison with qualitative scales easier. Patients surviving more than 48 hours were included in the analysis of DCI predisposing factors and analyzed using the chi-square or the Mann-Whitney U-tests. Logistic regression analysis was used for predicting DCI and outcome in the different quartiles of bleeding volume to obtain adjusted ORs. The diagnostic accuracy of each scale was obtained by calculating the area under the receiver operating characteristic curve (AUC). Qualitative scores showed a moderate interobserver

  14. Occurrence of Medication Errors and Comparison of Manual and Computerized Prescription Systems in Public Sector Hospitals in Lahore, Pakistan

    PubMed Central

    Riaz, Muhammad Kashif; Hashmi, Furqan Khurshid; Bukhari, Nadeem Irfan; Riaz, Mohammad; Hussain, Khalid

    2014-01-01

    The knowledge of medication errors is an essential prerequisite for better healthcare delivery. The present study investigated prescribing errors in prescriptions from outpatient departments (OPDs) and emergency wards of two public sector hospitals in Lahore, Pakistan. A manual prescription system was followed in Hospital A. Hospital B was running a semi-computerised prescription system in the OPD and a fully computerised prescription system in the emergency ward. A total of 510 prescriptions from both departments of these two hospitals were evaluated for patient characteristics, demographics and medication errors. The data was analysed using a chi square test for comparison of errors between both the hospitals. The medical departments in OPDs of both hospitals were the highest prescribers at 45%–60%. The age group receiving the most treatment in emergency wards of both the hospitals was 21–30 years (21%–24%). A trend of omitting patient addresses and diagnoses was observed in almost all prescriptions from both of the hospitals. Nevertheless, patient information such as name, age, gender and legibility of the prescriber’s signature were found in almost 100% of the electronic-prescriptions. In addition, no prescribing error was found pertaining to drug concentrations, quantity and rate of administration in e-prescriptions. The total prescribing errors in the OPD and emergency ward of Hospital A were found to be 44% and 60%, respectively. In hospital B, the OPD had 39% medication errors and the emergency department had 73.5% errors; this unexpected difference between the emergency ward and OPD of hospital B was mainly due to the inclusion of 69.4% omissions of route of administration in the prescriptions. The incidence of prescription overdose was approximately 7%–19% in the manual system and approximately 8% in semi and fully electronic system. The omission of information and incomplete information are contributors of prescribing errors in both manual and

  15. Innovations in Computerized Assessment.

    ERIC Educational Resources Information Center

    Drasgow, Fritz, Ed.; Olson-Buchanan, Julie B., Ed.

    Chapters in this book present the challenges and dilemmas faced by researchers as they created new computerized assessments, focusing on issues addressed in developing, scoring, and administering the assessments. Chapters are: (1) "Beyond Bells and Whistles; An Introduction to Computerized Assessment" (Julie B. Olson-Buchanan and Fritz Drasgow);…

  16. The use of high resolution computerized tomography (HRCT) of the chest in evaluating the effect of tobramycin solution for inhalation in cystic fibrosis lung disease.

    PubMed

    Nasr, Samya Z; Sakmar, Ermelinda; Christodoulou, Emmanuel; Eckhardt, Boris P; Streetman, Daniel S; Strouse, Peter J

    2010-05-01

    To compare the usefulness of HRCT of the chest versus spirometric measures (PFTs) in evaluating the effect of tobramycin solution for inhalation (TSI) in cystic fibrosis (CF). Thirty-two CF patients with mostly mild lung disease age > or = 6 years, were enrolled in a double-blind, placebo-controlled pilot study. Patients were chronically colonized with Pseudomonas aeruginosa for at least 6 months prior to and at enrollment. If patients were on TSI, they were taken off for at least 3 months prior to enrollment. Duration was 6 months; 31 subjects completed the study. HRCT and PFTs were evaluated at baseline, after 28 days of treatment and at the end of the study. Study medication was administered as 5 ml nebulized treatment twice a day for 28 days followed by 28 days off (one cycle). Study consisted of three cycles. Two radiologists scored all films using a validated system. A total HRCT score consists of the sum of subscores: linear opacities, hyperinflation, nodular opacities, peribronchial thickening, mucous plugging, and bronchiectasis; each subscore could range from 0 to 80, with potential total scores varying from 0 to 480. The percent of the maximum possible HRCT score was then calculated and used for all comparisons. Using two tailed paired t-test, the percent maximum HRCT score decreased by 1.4 +/- 2.6% (mean +/- SD) (P = 0.049) and 0.3 +/- 2.8% (P = 0.63) for the TSI group and decreased by 0.1 +/- 1.5% (P = 0.74) and increased by 0.6 +/- 1.8% (P = 0.23) for the placebo group between visits 1 and 2, and visits 1 and 3, respectively. The data were then analyzed using a mixed model utilizing changes in scores over the durations of the study for each group. The change of HRCT score for the TSI group was -0.24/day (P = 0.02) and -0.03/day (P = 0.22), and for the control group the change was -0.01 (P = 0.93) and 0.02 (P = 0.29) between visits 1 and 2, and visits 1 and 3 respectively. FEF(25-75)% and FEV(1)% changes were not statistically significant using both

  17. Comparison of diffuse optical tomography of human breast with whole-body and breast-only positron emission tomography

    PubMed Central

    Konecky, Soren D.; Choe, Regine; Corlu, Alper; Lee, Kijoon; Wiener, Rony; Srinivas, Shyam M.; Saffer, Janet R.; Freifelder, Richard; Karp, Joel S.; Hajjioui, Nassim; Azar, Fred; Yodh, Arjun G.

    2008-01-01

    We acquire and compare three-dimensional tomographic breast images of three females with suspicious masses using diffuse optical tomography (DOT) and positron emission tomography (PET). Co-registration of DOT and PET images was facilitated by a mutual information maximization algorithm. We also compared DOT and whole-body PET images of 14 patients with breast abnormalities. Positive correlations were found between total hemoglobin concentration and tissue scattering measured by DOT, and fluorodeoxyglucose (18F-FDG) uptake. In light of these observations, we suggest potential benefits of combining both PET and DOT for characterization of breast lesions. PMID:18383664

  18. Comparison of diffuse optical tomography of human breast with whole-body and breast-only positron emission tomography.

    PubMed

    Konecky, Soren D; Choe, Regine; Corlu, Alper; Lee, Kijoon; Wiener, Rony; Srinivas, Shyam M; Saffer, Janet R; Freifelder, Richard; Karp, Joel S; Hajjioui, Nassim; Azar, Fred; Yodh, Arjun G

    2008-02-01

    We acquire and compare three-dimensional tomographic breast images of three females with suspicious masses using diffuse optical tomography (DOT) and positron emission tomography (PET). Co-registration of DOT and PET images was facilitated by a mutual information maximization algorithm. We also compared DOT and whole-body PET images of 14 patients with breast abnormalities. Positive correlations were found between total hemoglobin concentration and tissue scattering measured by DOT, and fluorodeoxyglucose (18F-FDG) uptake. In light of these observations, we suggest potential benefits of combining both PET and DOT for characterization of breast lesions.

  19. Computed tomography for the detection of thumb base osteoarthritis: comparison with digital radiography.

    PubMed

    Saltzherr, Michael S; van Neck, Johan W; Muradin, Galied S R; Ouwendijk, Rody; Luime, Jolanda J; Coert, J Henk; Hovius, Steven E R; Selles, Ruud W

    2013-05-01

    To compare computed tomography (CT) with digital radiography for the detection of osteoarthritis (OA) of the first carpometacarpal (CMC1) and scaphotrapeziotrapezoid (STT) joint. We retrospectively identified patients who were assessed for CMC1 OA or STT OA at our hand surgery outpatient clinic between January 2008 and March 2011, and who had both a digital radiograph and a CT scan of the hand within a 3-month period. CT and radiographic images were scored independently by two musculoskeletal radiologists for joint space narrowing (JSN), osteophytes, subchondral sclerosis, bone cysts, and erosions in the CMC1 and STT joints. Thirty patients were identified. The inter-reader reliability of CT for the detection of CMC1 OA (ICC 1.00) and STT OA (ICC 0.80) was higher than radiography (ICC's 0.15 and 0.45). In comparison with their own radiographical scoring, both readers detected with CT 3 more patients with CMC1 OA, and 13 and 5 more patients with STT OA. Computed tomography had a higher inter-reader reliability and detection rate for both CMC1 and STT OA, compared with radiography. As surgical treatment selection of thumb base OA depends on the presence of pathology in the CMC1 and STT joints, CT may improve treatment selection and surgical planning.

  20. Comparison of sound speed measurements on two different ultrasound tomography devices.

    PubMed

    Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Sherman, Mark; Gierach, Gretchen; Malyarenko, Antonina

    2014-03-20

    Ultrasound tomography (UST) employs sound waves to produce three-dimensional images of breast tissue and precisely measures the sound speed of breast tissue composition. High breast density is a strong breast cancer risk factor and sound speed is directly proportional to breast density. UST provides a quantitative measure of breast density based on three-dimensional imaging without compression, thereby overcoming the shortcomings of many other imaging modalities. The quantitative nature of the UST breast density measures are tied to an external standard, so sound speed measurement in breast tissue should be independent of specific hardware. The work presented here compares breast sound speed measurement obtained with two different UST devices. The Computerized Ultrasound Risk Evaluation (CURE) system located at the Karmanos Cancer Institute in Detroit, Michigan was recently replaced with the SoftVue ultrasound tomographic device. Ongoing clinical trials have used images generated from both sets of hardware, so maintaining consistency in sound speed measurements is important. During an overlap period when both systems were in the same exam room, a total of 12 patients had one or both of their breasts imaged on both systems on the same day. There were 22 sound speed scans analyzed from each system and the average breast sound speeds were compared. Images were either reconstructed using saved raw data (for both CURE and SoftVue) or were created during the image acquisition (saved in DICOM format for SoftVue scans only). The sound speed measurements from each system were strongly and positively correlated with each other. The average difference in sound speed between the two sets of data was on the order of 1-2 m/s and this result was not statistically significant. The only sets of images that showed a statistical difference were the DICOM images created during the SoftVue scan compared to the SoftVue images reconstructed from the raw data. However, the discrepancy

  1. Comparison of sound speed measurements on two different ultrasound tomography devices

    NASA Astrophysics Data System (ADS)

    Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Sherman, Mark; Gierach, Gretchen; Malyarenko, Antonina

    2014-03-01

    Ultrasound tomography (UST) employs sound waves to produce three-dimensional images of breast tissue and precisely measures the attenuation of sound speed secondary to breast tissue composition. High breast density is a strong breast cancer risk factor and sound speed is directly proportional to breast density. UST provides a quantitative measure of breast density based on three-dimensional imaging without compression, thereby overcoming the shortcomings of many other imaging modalities. The quantitative nature of the UST breast density measures are tied to an external standard, so sound speed measurement in breast tissue should be independent of specific hardware. The work presented here compares breast sound speed measurement obtained with two different UST devices. The Computerized Ultrasound Risk Evaluation (CURE) system located at the Karmanos Cancer Institute in Detroit, Michigan was recently replaced with the SoftVue ultrasound tomographic device. Ongoing clinical trials have used images generated from both sets of hardware, so maintaining consistency in sound speed measurements is important. During an overlap period when both systems were in the same exam room, a total of 12 patients had one or both of their breasts imaged on both systems on the same day. There were 22 sound speed scans analyzed from each system and the average breast sound speeds were compared. Images were either reconstructed using saved raw data (for both CURE and SoftVue) or were created during the image acquisition (saved in DICOM format for SoftVue scans only). The sound speed measurements from each system were strongly and positively correlated with each other. The average difference in sound speed between the two sets of data was on the order of 1-2 m/s and this result was not statistically significant. The only sets of images that showed a statistical difference were the DICOM images created during the SoftVue scan compared to the SoftVue images reconstructed from the raw data

  2. Comparison of sound speed measurements on two different ultrasound tomography devices

    PubMed Central

    Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Sherman, Mark; Gierach, Gretchen; Malyarenko, Antonina

    2014-01-01

    Ultrasound tomography (UST) employs sound waves to produce three-dimensional images of breast tissue and precisely measures the sound speed of breast tissue composition. High breast density is a strong breast cancer risk factor and sound speed is directly proportional to breast density. UST provides a quantitative measure of breast density based on three-dimensional imaging without compression, thereby overcoming the shortcomings of many other imaging modalities. The quantitative nature of the UST breast density measures are tied to an external standard, so sound speed measurement in breast tissue should be independent of specific hardware. The work presented here compares breast sound speed measurement obtained with two different UST devices. The Computerized Ultrasound Risk Evaluation (CURE) system located at the Karmanos Cancer Institute in Detroit, Michigan was recently replaced with the SoftVue ultrasound tomographic device. Ongoing clinical trials have used images generated from both sets of hardware, so maintaining consistency in sound speed measurements is important. During an overlap period when both systems were in the same exam room, a total of 12 patients had one or both of their breasts imaged on both systems on the same day. There were 22 sound speed scans analyzed from each system and the average breast sound speeds were compared. Images were either reconstructed using saved raw data (for both CURE and SoftVue) or were created during the image acquisition (saved in DICOM format for SoftVue scans only). The sound speed measurements from each system were strongly and positively correlated with each other. The average difference in sound speed between the two sets of data was on the order of 1-2 m/s and this result was not statistically significant. The only sets of images that showed a statistical difference were the DICOM images created during the SoftVue scan compared to the SoftVue images reconstructed from the raw data. However, the discrepancy

  3. Prognostic Contribution of Exercise Capacity, Heart Rate Recovery, Chronotropic Incompetence, and Myocardial Perfusion Single-Photon Emission Computerized Tomography in the Prediction of Cardiac Death and All-Cause Mortality.

    PubMed

    Arbit, Boris; Azarbal, Babak; Hayes, Sean W; Gransar, Heidi; Germano, Guido; Friedman, John D; Thomson, Louise; Berman, Daniel S

    2015-12-01

    Chronotropic incompetence, measured by the percentage (%) of heart rate (HR) reserve achieved (%HR reserve), abnormal HR recovery, reduced exercise capacity (EC), and myocardial perfusion single-photon emission computerized tomography (SPECT MPS) abnormalities are known predictors of all-cause mortality (ACM) and cardiac death (CD). The aim of this study was to determine if EC, %HR reserve, and HR recovery add incremental value to MPS in the prediction of ACM and CD. A total of 11,218 patients without valvular disease and not on β blockers underwent symptom-limited exercise MPS. %HR reserve was (peak HR - rest HR)/(220 - age - rest HR) × 100, with %HR reserve <80 defined as low. HR recovery was peak HR - recovery HR. An HR recovery <22 beats/min at 2 minutes after peak exercise was considered abnormal. Poor EC was defined as exercise duration ≤6 minutes (7 metabolic equivalents). Summed stress scores (SSSs) were calculated using a 20-segment, 5-point MPS model. Statistical analysis was performed using Cox regression models. There were 445 deaths (148 CD) during a mean follow-up of 3.2 ± 2.5 years. In multivariate analysis, the independent predictors of ACM were age, χ(2) = 154.81; EC, χ(2) = 74.00; SSS, χ(2) = 32.99; %HR reserve, χ(2) = 24.74; abnormal electrocardiogram at rest, χ(2) = 23.13; HR recovery, χ(2) = 18.45; diabetes, χ(2) = 17.75; and previous coronary artery disease, χ(2) = 11.85 (p ≤0.0006). The independent predictors of CD were SSS, χ(2) = 54.25; EC, χ(2) = 49.34; age, χ(2) = 46.45; abnormal electrocardiogram at rest, χ(2) = 30.60; previous coronary artery disease, χ(2) = 20.69; Duke treadmill score, χ(2) = 19.50; %HR reserve, χ(2) = 11.43; diabetes, χ(2) = 10.23 (all p ≤0.0014); and HR recovery, χ(2) = 5.30 (p = 0.0214). The exercise variables showed increases in Harrell's C static and net improvement reclassification, with EC showing the strongest incremental improvement in predicting ACM and CD (respective C-index 76

  4. [Patient dose optimization in pediatric computerized tomography].

    PubMed

    Verdun, F R; Schnyder, P; Gutièrrez, D; Gudinchet, F

    2006-07-12

    The development of CT applications might become a public health problem if no effort is made on the justification and the optimisation of the examinations. This paper presents some hints to assure that the risk-benefit compromise remains in favour of the patient, especially when one deals with the examinations of young patients. In this context a particular attention has to be made on the justification of the examination. When performing the acquisition one needs to optimise the extension of the volume investigated together with the number of acquisition sequences used. Finally, the use of automatic exposure systems, now available on all the units, and the use of the Diagnostic Reference Levels (DRL) should allow help radiologists to control the exposure of their patients.

  5. Computerized tomography using video recorded fluoroscopic images

    NASA Technical Reports Server (NTRS)

    Kak, A. C.; Jakowatz, C. V., Jr.; Baily, N. A.; Keller, R. A.

    1977-01-01

    The use of video-recorded fluoroscopic images as input data for digital reconstruction of objects from their projections is examined. The fluoroscopic and the scanning apparatus used for the experiments are of a commercial type already in existence in most hospitals. It is shown that for beams with divergence up to about 15 deg, one can use a convolution algorithm designed for the parallel radiation case with negligible degradation both quantitatively and from a visual quality standpoint. This convolution algorithm is computationally more efficient than either the algebraic techniques or the convolution algorithms for radially diverging data. Results from studies on Lucite phantoms and a freshly sacrificed rat are included.

  6. In vitro comparison of plain radiography, double-contrast cystography, ultrasonography, and computed tomography for estimation of cystolith size.

    PubMed

    Byl, Kevin M; Kruger, John M; Kinns, Jennifer; Nelson, Nathan C; Hauptman, Joe G; Johnson, Cheri A

    2010-03-01

    To compare accuracy of estimates of cystolith size obtained by means of plain radiography, double-contrast cystography, ultrasonography, and computed tomography. 30 canine cystoliths ranging from 1 to 11 mm in diameter with various mineral compositions. A bladder phantom model was created by filling a rubber balloon with saline (1% NaCl) solution and positioning it on top of a 2% gelatin cushion at the bottom of a water-filled 4-quart container. Cystoliths were individually placed in the bladder phantom and imaged by each of the 4 techniques. For each image, cystolith size was measured by 2 radiologists with computerized calipers, and size estimates were compared with actual cystolith size. Mean cystolith size estimates obtained by means of radiography, cystography, and computed tomography did not differ significantly from each other. However, for ultrasonographic images, mean +/- SD difference between actual and estimated cystolith size (2.95 +/- 0.73 mm) was significantly higher than mean difference for radiographic, cystographic, and computed tomographic images. For ultrasonography, mean +/- SD percentage overestimation in cystolith size was 68.4 +/- 51.5%. Results indicated that measurements of cystolith size obtained by means of ultrasonography may overestimate the true size. This suggests that cystolith size estimates obtained by means of ultrasonography should be interpreted with caution whenever cystolith size may influence patient management.

  7. Comparison of optical coherence tomography, microcomputed tomography, and histology at a three-dimensionally imaged trabecular bone sample

    NASA Astrophysics Data System (ADS)

    Kasseck, Christoph; Kratz, Marita; Torcasio, Antonia; Gerhardt, Nils C.; van Lenthe, G. Harry; Gambichler, Thilo; Hoffmann, Klaus; Jones, David B.; Hofmann, Martin R.

    2010-07-01

    We investigate optical coherence tomography (OCT) as a method for imaging bone. The OCT images are compared directly to those of the standard methods of bone histology and microcomputed tomography (μCT) on a single, fixed human femoral trabecular bone sample. An advantage of OCT over bone histology is its noninvasive nature. OCT also images the lamellar structure of trabeculae at slightly higher contrast than normal bone histology. While μCT visualizes the trabecular framework of the whole sample, OCT can image additionally cells with a penetration depth limited approximately to 1 mm. The most significant advantage of OCT, however, is the absence of toxic effects (no ionizing radiation), i.e., continuous images may be made and individual cell tracking may be performed. The penetration depth of OCT, however, limits its use to small animal models and small bone organ cultures.

  8. Reliability and Validity of the Computerized Revised Token Test: Comparison of Reading and Listening Versions in Persons with and without Aphasia

    ERIC Educational Resources Information Center

    McNeil, Malcolm R.; Pratt, Sheila R.; Szuminsky, Neil; Sung, Jee Eun; Fossett, Tepanta R. D.; Fassbinder, Wiltrud; Lim, Kyoung Yuel

    2015-01-01

    Purpose: This study assessed the reliability and validity of intermodality associations and differences in persons with aphasia (PWA) and healthy controls (HC) on a computerized listening and 3 reading versions of the Revised Token Test (RTT; McNeil & Prescott, 1978). Method: Thirty PWA and 30 HC completed the test versions, including a…

  9. A Comparison of Item Selection Procedures Using Different Ability Estimation Methods in Computerized Adaptive Testing Based on the Generalized Partial Credit Model

    ERIC Educational Resources Information Center

    Ho, Tsung-Han

    2010-01-01

    Computerized adaptive testing (CAT) provides a highly efficient alternative to the paper-and-pencil test. By selecting items that match examinees' ability levels, CAT not only can shorten test length and administration time but it can also increase measurement precision and reduce measurement error. In CAT, maximum information (MI) is the most…

  10. A Comparison of Cognitive Bias Modification for Interpretation and Computerized Cognitive Behavior Therapy: Effects on Anxiety, Depression, Attentional Control, and Interpretive Bias

    ERIC Educational Resources Information Center

    Bowler, Jennifer O.; Mackintosh, Bundy; Dunn, Barnaby D.; Mathews, Andrew; Dalgleish, Tim; Hoppitt, Laura

    2012-01-01

    Objective: Computerized cognitive behavioral therapy (cCBT) and cognitive bias modification for interpretation (CBM-I) both have demonstrated efficacy in alleviating social anxiety, but how they compare with each other has not been investigated. The present study tested the prediction that both interventions would reduce anxiety relative to a…

  11. A Comparison of Content-Balancing Procedures for Estimating Multiple Clinical Domains in Computerized Adaptive Testing: Relative Precision, Validity, and Detection of Persons with Misfitting Responses

    ERIC Educational Resources Information Center

    Riley, Barth B.; Dennis, Michael L.; Conrad, Kendon J.

    2010-01-01

    This simulation study sought to compare four different computerized adaptive testing (CAT) content-balancing procedures designed for use in a multidimensional assessment with respect to measurement precision, symptom severity classification, validity of clinical diagnostic recommendations, and sensitivity to atypical responding. The four…

  12. Learning Complex Grammar in the Virtual Classroom: A Comparison of Processing Instruction, Structured Input, Computerized Visual Input Enhancement, and Traditional Instruction

    ERIC Educational Resources Information Center

    Russell, Victoria

    2012-01-01

    This study investigated the effects of processing instruction (PI) and structured input (SI) on the acquisition of the subjunctive in adjectival clauses by 92 second-semester distance learners of Spanish. Computerized visual input enhancement (VIE) was combined with PI and SI in an attempt to increase the salience of the targeted grammatical form…

  13. Learning Complex Grammar in the Virtual Classroom: A Comparison of Processing Instruction, Structured Input, Computerized Visual Input Enhancement, and Traditional Instruction

    ERIC Educational Resources Information Center

    Russell, Victoria

    2012-01-01

    This study investigated the effects of processing instruction (PI) and structured input (SI) on the acquisition of the subjunctive in adjectival clauses by 92 second-semester distance learners of Spanish. Computerized visual input enhancement (VIE) was combined with PI and SI in an attempt to increase the salience of the targeted grammatical form…

  14. Reliability and Validity of the Computerized Revised Token Test: Comparison of Reading and Listening Versions in Persons with and without Aphasia

    ERIC Educational Resources Information Center

    McNeil, Malcolm R.; Pratt, Sheila R.; Szuminsky, Neil; Sung, Jee Eun; Fossett, Tepanta R. D.; Fassbinder, Wiltrud; Lim, Kyoung Yuel

    2015-01-01

    Purpose: This study assessed the reliability and validity of intermodality associations and differences in persons with aphasia (PWA) and healthy controls (HC) on a computerized listening and 3 reading versions of the Revised Token Test (RTT; McNeil & Prescott, 1978). Method: Thirty PWA and 30 HC completed the test versions, including a…

  15. Computerized Construction Planning

    ERIC Educational Resources Information Center

    Moucka, Jan; Piskova, Vera

    1971-01-01

    Two Czechoslovakian architects describe how they scheduled construction projects on a statewide scale by computerizing the priority for projects, the resource capacity, the time coordination, and the construction schedules. (Author)

  16. Computerized Interactive Harness Engineering

    NASA Technical Reports Server (NTRS)

    Billitti, J. W.

    1985-01-01

    Computerized interactive harness engineering program inexpensive, interactive system for learning and using engineering approach to interconnection systems. Basically data-base system that stores information as files of individual connectors and handles wiring information in circuit groups stored as records.

  17. Comparison of optoacoustic tomography with ultrasound and x-ray imaging for breast cancer detection

    NASA Astrophysics Data System (ADS)

    Larin, Kirill V.; Hartrumpf, O.; Larina, Irina V.; Esenaliev, Rinat O.

    2001-06-01

    This paper is devoted to comparison new optoacoustic tomography with conventional breast tumors diagnostic techniques such as ultrasonography and X-ray radiography. Experiments were performed in phantoms simulating breast with tumors. The fundamental harmonic of Q-switched Nd:YAG laser (λ = 1064 nm) was used to generate optoacoustic pressure waves. Laser induced pressure waves were detected by a wide-band acoustic transducer. Digital oscilloscope controlled by PC was used to store and process optoacoustic signals. Gelatin phantoms with controlled optical parameters were prepared to simulate breast with tumors. Absorbing volumes colored with naphthol green and hemoglobin were embedded in the gelatin phantoms to model the breast tumors with increased optical absorption. Optoacoustic pressure waves form the phantoms were detected at different angles and 2D images were reconstructed. Comparison of optoacoustic images with images obtained with ultrasound and X-ray techniques proved that optoacoustic method has substantially higher contrast and resolution. Obtained results confirm that laser optoacoustic imaging technique can be an important tool for early breast cancer detection with tumors less than 5 mm in diameter.

  18. Comparison of computed tomography dose index in polymethyl methacrylate and nylon dosimetry phantoms

    PubMed Central

    Sookpeng, Supawitoo; Cheebsumon, Patsuree; Pengpan, Thanyawee; Martin, Colin

    2016-01-01

    The use of computed tomography (CT) scanning has been growing steadily. Therefore, CT dose measurement is becoming increasingly important for patient protection and optimization. A phantom is an important tool for dose measurement. This paper focuses on the evaluation of a CT dosimetry phantom made from nylon, instead of the standard polymethyl methacrylate (PMMA), which is not readily available or is too expensive in some countries. Comparison between phantoms made from the two materials is made in terms of measurements of the CT dose indices (CTDI). These were measured for four different beam widths and kVp settings at the center and periphery in head and body phantoms made from both materials and weighted CTDIs (CTDIw) were calculated. CT numbers along the z-axis of the phantom were also measured at the center and four peripheral positions of each scanned slice to check phantom homogeneity. Results showed that values for the CTDIw measured in the nylon phantoms were slightly higher than those from the PMMA while CT numbers for nylon were lower than those of PMMA. This is because the mass attenuation coefficient of the nylon is higher. Nylon could be used as a substitute material for CT dosimetry phantom to enable measurements and adjustment factors are given which could be used to estimate PMMA values for making comparisons with displayed values. PMID:27051170

  19. Variations in optical coherence tomography resolution and uniformity: a multi-system performance comparison

    PubMed Central

    Fouad, Anthony; Pfefer, T. Joshua; Chen, Chao-Wei; Gong, Wei; Agrawal, Anant; Tomlins, Peter H.; Woolliams, Peter D.; Drezek, Rebekah A.; Chen, Yu

    2014-01-01

    Point spread function (PSF) phantoms based on unstructured distributions of sub-resolution particles in a transparent matrix have been demonstrated as a useful tool for evaluating resolution and its spatial variation across image volumes in optical coherence tomography (OCT) systems. Measurements based on PSF phantoms have the potential to become a standard test method for consistent, objective and quantitative inter-comparison of OCT system performance. Towards this end, we have evaluated three PSF phantoms and investigated their ability to compare the performance of four OCT systems. The phantoms are based on 260-nm-diameter gold nanoshells, 400-nm-diameter iron oxide particles and 1.5-micron-diameter silica particles. The OCT systems included spectral-domain and swept source systems in free-beam geometries as well as a time-domain system in both free-beam and fiberoptic probe geometries. Results indicated that iron oxide particles and gold nanoshells were most effective for measuring spatial variations in the magnitude and shape of PSFs across the image volume. The intensity of individual particles was also used to evaluate spatial variations in signal intensity uniformity. Significant system-to-system differences in resolution and signal intensity and their spatial variation were readily quantified. The phantoms proved useful for identification and characterization of irregularities such as astigmatism. Our multi-system results provide evidence of the practical utility of PSF-phantom-based test methods for quantitative inter-comparison of OCT system resolution and signal uniformity. PMID:25071949

  20. Comparison of radiography and computed tomography to evaluate fractures of the canine tarsus.

    PubMed

    Butler, Danielle; Nemanic, Sarah; Warnock, Jennifer J

    2017-09-03

    Detection and accurate classification of traumatic tarsal fractures are important for identifying cases requiring surgical intervention. The aim of this prospective, experimental, methods comparison study was to directly compare the accuracy, sensitivity, and specificity of tarsal computed tomography (CT), ten-view and two-view digital radiographs for detecting traumatic fractures of the canine tarsus. The working hypothesis was that tarsal fractures would be detected with higher accuracy, sensitivity, and specificity using CT imaging compared to radiography, and a ten-view would be superior to a two-view radiographic study. Ten cadaver hind limbs of medium to large dogs received a CT scan and ten-view radiographic study before and after induction of fractures with a hydraulic press. All bones included in the radiographic images were assessed for fractures by two observers and gross dissection was used as the gold standard. The two-view radiographic study (dorsoplantar, lateromedial) was created from the ten-view study and reviewed 2 years later. All limbs sustained fractures, the most common locations were the talus and calcaneus (n = 7). The sensitivity of CT was greater than ten-view radiographic study (77% vs. 57%), while the specificity was similar (97% vs. 98%). The sensitivity and specificity of the ten-view and two-view radiograph studies were similar (57% vs. 55%; both 98%). Computed tomography images were reassessed postdissection to determine if failure to identify fractures resulted from observer error. Overall, CT was better than radiography for detecting fractures of the canine tarsus, however there was little improvement with ten-view compared to two-view radiographic studies. © 2017 American College of Veterinary Radiology.

  1. Special computer-aided computed tomography (CT) volume measurement and comparison method for pulmonary tuberculosis (TB).

    PubMed

    Liu, Jingming; Sun, Zhaogang; Xie, Ruming; Gao, Mengqiu; Li, Chuanyou

    2015-01-01

    The computed tomography (CT) manifestations in pulmonary tuberculosis (PTB) patients are complex and could not be quantitatively evaluated. We aimed to establish a new method to objectively measure the lung injury level in PTB by thoracic CT and make quantitative comparisons. In the retrospective study, a total of 360 adults were selected and divided into four groups according to their CT manifestations and medical history: Normal group, PTB group, PTB with diabetes mellitus (DM) group and Death caused by PTB group. Five additional patients who had continuous CT scans were chosen for preliminary longitudinal analysis. We established a new computer-aided CT volume measurement and comparison method for PTB patients (CACTV-PTB) which measured lung volume (LV) and thoracic volume (TV). RLT was calculated as the ratio of LV to TV and comparisons were performed among different groups. Standardized RLT (SRLT) was used in the longitudinal analysis among different patients. In the Normal group, LV and TV were positively correlated in linear regression (Ŷ=-0.5+0.46X, R(2)=0.796, P<0.01). RLT values were significantly different among four groups (Normal: 0.40±0.05, PTB: 0.37±0.08, PTB+DM: 0.34±0.06, Death: 0.23±0.04). The curves of SRLT value from different patients shared a same start point and could be compared directly. Utilizing the novel objective method CACTV-PTB makes it possible to compare the severity and dynamic change among different PTB patients. Our early experience also suggested that the lung injury is severer in the PTB+DM group than in the PTB group.

  2. Optical Tomography of a Sunspot. I. Comparison between Two Inversion Techniques

    NASA Astrophysics Data System (ADS)

    Westendorp Plaza, C.; del Toro Iniesta, J. C.; Ruiz Cobo, B.; Martínez Pillet, V.; Lites, B. W.; Skumanich, A.

    1998-02-01

    A quantitative comparison between the Milne-Eddington (ME) inversion technique implemented by Skumanich & Lites and the SIR (Stokes Inversion based on Response Functions) proposed by Ruiz Cobo & del Toro Iniesta is presented. Numerical experiments are carried out to explore the capabilities and limitations of both diagnostic techniques. Such experiments consist of inversions of Stokes profiles previously synthesized in ``realistic'' solar atmospheric models. The results show that the ME inversion provides accurate, line-of-sight (LOS) averaged values for the input stratification of the vector magnetic field. Its greater speed compared to SIR makes it useful for quick analysis of large quantities of data (such as those currently provided by modern spectropolarimeters) if one is only interested in LOS-averaged quantities. However, the higher order description of the atmosphere used by SIR (which acknowledges variation of the thermal, dynamic, and magnetic parameters through the photosphere) allows retrieval of the stratification of all these parameters to good accuracy. This is so even in the presence of discontinuities such as those foreseen in magnetic canopies of sunspots. The trade-offs between thermodynamic and magnetic parameters observed in some ME inversions are reduced considerably in the case of SIR inversions because of the more realistic treatment of the thermodynamics in this analysis. Notably, both allow one to extract quantitative inferences of fairly weak magnetic fields (below 500 G), even when they are applied to Zeeman-sensitive lines in the visible spectrum; i.e., well below the commonly accepted limit of 500 G. The thermodynamic parameters resulting from the ME inversion are understood theoretically in terms of the generalized response functions introduced by Ruiz Cobo & del Toro Iniesta and through the concept of height of formation for inferred values proposed by Sánchez Almeida, Ruiz Cobo, & del Toro Iniesta. The present comparison and

  3. Assessment of natural enamel lesions with optical coherence tomography in comparison with microfocus x-ray computed tomography

    PubMed Central

    Espigares, Jorge; Sadr, Alireza; Hamba, Hidenori; Shimada, Yasushi; Otsuki, Masayuki; Tagami, Junji; Sumi, Yasunori

    2015-01-01

    Abstract. A technology to characterize early enamel lesions is needed in dentistry. Optical coherence tomography (OCT) is a noninvasive method that provides high-resolution cross-sectional images. The aim of this study is to compare OCT with microfocus x-ray computed tomography (μCT) for assessment of natural enamel lesions in vitro. Ten human teeth with visible white spot-like changes on the enamel smooth surface and no cavitation (ICDAS code 2) were subjected to imaging by μCT (SMX-100CT, Shimadzu) and 1300-nm swept-source OCT (Dental SS-OCT, Panasonic Health Care). In μCT, the lesions appeared as radiolucent dark areas, while in SS-OCT, they appeared as areas of increased signal intensity beneath the surface. An SS-OCT attenuation coefficient based on Beer–Lambert law could discriminate lesions from sound enamel. Lesion depth ranged from 175 to 606  μm in SS-OCT. A correlation between μCT and SS-OCT was found regarding lesion depth (R=0.81, p<0.001) and also surface layer thickness (R=0.76, p<0.005). The images obtained clinically in real time using the dental SS-OCT system are suitable for the assessment of natural subsurface lesions and their surface layer, providing comparable images to a laboratory high-resolution μCT without the use of x-ray. PMID:26158079

  4. Digital Tomosynthesis and High Resolution Computed Tomography as Clinical Tools for Vertebral Endplate Topography Measurements: Comparison with Microcomputed Tomography

    PubMed Central

    Oravec, Daniel; Quazi, Abrar; Xiao, Angela; Yang, Ellen; Zauel, Roger; Flynn, Michael J.; Yeni, Yener N.

    2015-01-01

    Endplate morphology is understood to play an important role in the mechanical behavior of vertebral bone as well as degenerative processes in spinal tissues; however, the utility of clinical imaging modalities in assessment of the vertebral endplate has been limited. The objective of this study was to evaluate the ability of two clinical imaging modalities (digital tomosynthesis, DTS; high resolution computed tomography, HRCT) to assess endplate topography by correlating the measurements to a microcomputed tomography (µCT) standard. DTS, HRCT, and µCT images of 117 cadaveric thoracolumbar vertebrae (T10-L1; 23 male, 19 female; ages 36–100 years) were segmented, and inferior and superior endplate surface topographical distribution parameters were calculated. Both DTS and HRCT showed statistically significant correlations with µCT approaching a moderate level of correlation at the superior endplate for all measured parameters (R2Adj=0.19–0.57), including averages, variability, and higher order statistical moments. Correlation of average depths at the inferior endplate was comparable to the superior case for both DTS and HRCT (R2Adj=0.14–0.51), while correlations became weak or nonsignificant for higher moments of the topography distribution. DTS was able to capture variations in the endplate topography to a slightly better extent than HRCT, and taken together with the higher speed and lower radiation cost of DTS than HRCT, DTS appears preferable for endplate measurements. PMID:26220145

  5. Nondestructive observation of teeth post core-space using optical coherence tomography: comparison with microcomputed tomography and live images

    NASA Astrophysics Data System (ADS)

    Minamino, Takuya; Mine, Atsushi; Matsumoto, Mariko; Sugawa, Yoshihiko; Kabetani, Tomoshige; Higashi, Mami; Kawaguchi, Asuka; Ohmi, Masato; Awazu, Kunio; Yatani, Hirofumi

    2015-10-01

    No previous reports have observed inside the root canal using both optical coherence tomography (OCT) and x-ray microcomputed tomography (μCT) for the same sample. The purpose of this study was to clarify both OCT and μCT image properties from observations of the same root canal after resin core build-up treatment. As OCT allows real-time observation of samples, gap formation may be able to be shown in real time. A dual-cure, one-step, self-etch adhesive system bonding agent, and dual-cure resin composite core material were used in root canals in accordance with instructions from the manufacturer. The resulting OCT images were superior for identifying gap formation at the interface, while μCT images were better to grasp the tooth form. Continuous tomographic images from real-time OCT observation allowed successful construction of a video of the resin core build-up procedure. After 10 to 12 s of light curing, a gap with a clear new signal occurred at the root-core material interface, proceeding from the coronal side (6 mm from the cemento-enamel junction) to the apical side of the root.

  6. Digital tomosynthesis and high resolution computed tomography as clinical tools for vertebral endplate topography measurements: Comparison with microcomputed tomography.

    PubMed

    Oravec, Daniel; Quazi, Abrar; Xiao, Angela; Yang, Ellen; Zauel, Roger; Flynn, Michael J; Yeni, Yener N

    2015-12-01

    Endplate morphology is understood to play an important role in the mechanical behavior of vertebral bone as well as degenerative processes in spinal tissues; however, the utility of clinical imaging modalities in assessment of the vertebral endplate has been limited. The objective of this study was to evaluate the ability of two clinical imaging modalities (digital tomosynthesis, DTS; high resolution computed tomography, HRCT) to assess endplate topography by correlating the measurements to a microcomputed tomography (μCT) standard. DTS, HRCT, and μCT images of 117 cadaveric thoracolumbar vertebrae (T10-L1; 23 male, 19 female; ages 36-100 years) were segmented, and inferior and superior endplate surface topographical distribution parameters were calculated. Both DTS and HRCT showed statistically significant correlations with μCT approaching a moderate level of correlation at the superior endplate for all measured parameters (R(2)Adj=0.19-0.57), including averages, variability, and higher order statistical moments. Correlation of average depths at the inferior endplate was comparable to the superior case for both DTS and HRCT (R(2)Adj=0.14-0.51), while correlations became weak or nonsignificant for higher moments of the topography distribution. DTS was able to capture variations in the endplate topography to a slightly better extent than HRCT, and taken together with the higher speed and lower radiation cost of DTS than HRCT, DTS appears preferable for endplate measurements.

  7. Assessment of natural enamel lesions with optical coherence tomography in comparison with microfocus x-ray computed tomography.

    PubMed

    Espigares, Jorge; Sadr, Alireza; Hamba, Hidenori; Shimada, Yasushi; Otsuki, Masayuki; Tagami, Junji; Sumi, Yasunori

    2015-01-01

    A technology to characterize early enamel lesions is needed in dentistry. Optical coherence tomography (OCT) is a noninvasive method that provides high-resolution cross-sectional images. The aim of this study is to compare OCT with microfocus x-ray computed tomography ([Formula: see text]) for assessment of natural enamel lesions in vitro. Ten human teeth with visible white spot-like changes on the enamel smooth surface and no cavitation (ICDAS code 2) were subjected to imaging by μCT (SMX-100CT, Shimadzu) and 1300-nm swept-source OCT (Dental SS-OCT, Panasonic Health Care). In [Formula: see text], the lesions appeared as radiolucent dark areas, while in SS-OCT, they appeared as areas of increased signal intensity beneath the surface. An SS-OCT attenuation coefficient based on Beer-Lambert law could discriminate lesions from sound enamel. Lesion depth ranged from 175 to [Formula: see text] in SS-OCT. A correlation between [Formula: see text] and SS-OCT was found regarding lesion depth ([Formula: see text], [Formula: see text]) and also surface layer thickness ([Formula: see text], [Formula: see text]). The images obtained clinically in real time using the dental SS-OCT system are suitable for the assessment of natural subsurface lesions and their surface layer, providing comparable images to a laboratory high-resolution [Formula: see text] without the use of x-ray.

  8. Nondestructive observation of teeth post core-space using optical coherence tomography: comparison with microcomputed tomography and live images.

    PubMed

    Minamino, Takuya; Mine, Atsushi; Matsumoto, Mariko; Sugawa, Yoshihiko; Kabetani, Tomoshige; Higashi, Mami; Kawaguchi, Asuka; Ohmi, Masato; Awazu, Kunio; Yatani, Hirofumi

    2015-10-01

    No previous reports have observed inside the root canal using both optical coherence tomography (OCT) and x-ray microcomputed tomography (μCT) for the same sample. The purpose of this study was to clarify both OCT and μCT image properties from observations of the same root canal after resin core build-up treatment. As OCT allows real-time observation of samples, gap formation may be able to be shown in real time. A dual-cure, one-step, self-etch adhesive system bonding agent, and dual-cure resin composite core material were used in root canals in accordance with instructions from the manufacturer. The resulting OCT images were superior for identifying gap formation at the interface, while μCT images were better to grasp the tooth form. Continuous tomographic images from real-time OCT observation allowed successful construction of a video of the resin core build-up procedure. After 10 to 12 s of light curing, a gap with a clear new signal occurred at the root-core material interface, proceeding from the coronal side (6 mm from the cemento-enamel junction) to the apical side of the root.

  9. Value and limitation of stress thallium-201 single photon emission computed tomography: comparison with nitrogen-13 ammonia positron tomography

    SciTech Connect

    Tamaki, N.; Yonekura, Y.; Senda, M.; Yamashita, K.; Koide, H.; Saji, H.; Hashimoto, T.; Fudo, T.; Kambara, H.; Kawai, C.

    1988-07-01

    The diagnostic value of exercise /sup 201/Tl single photon emission computed tomography (SPECT) for assessing coronary artery disease (CAD) was comparatively evaluated with exercise (13N) ammonia positron emission tomography (PET). Fifty-one patients underwent both stress-delayed SPECT imaging using a rotational gamma camera and stress-rest PET imaging using a high resolution PET camera. Of 48 CAD patients, SPECT showed abnormal perfusion in 46 patients (96%), while PET detected perfusion abnormalities in 47 (98%). The sensitivity for detecting disease in individual coronary arteries (greater than 50% stenosis) was also similar for SPECT (81%) and PET (88%). When their interpretations were classified as normal, transient defect, and fixed defect in 765 myocardial segments, SPECT and PET findings were concordant in 606 segments (79%). However, 66 segments showed a fixed defect by SPECT but a transient defect by PET, whereas there were only nine segments showing a transient defect by SPECT and a fixed defect by PET. PET identified transient defects in 34% of the myocardial segments showing a fixed defect by SPECT. We conclude that both stress SPECT and PET showed high and similar sensitivities for detecting CAD and individual stenosed vessels. Since stress-delayed SPECT with single tracer injection detected fewer transient defects, it may underestimate the presence of myocardial ischemia, compared with high resolution PET imaging with two tracer injections.

  10. Comparison of objective diagnostic tests in glaucoma: Heidelberg retinal tomography and multifocal visual evoked potentials.

    PubMed

    Balachandran, C; Graham, S L; Klistorner, A; Goldberg, I

    2006-04-01

    To compare sensitivity and specificity of functional and structural changes in glaucoma using two objective tests: the multifocal visual evoked potential (m-VEP) and Heidelberg retinal tomography II (HRT). 41 glaucoma patients and 25 normal individuals participated in the study. One eye per individual was included in the study. Individuals were evaluated with Humphrey visual field (HVF) perimetry, m-VEP, and HRT. Moorfield regression analysis findings of HRT were compared with presence of scotoma on m-VEP. Linear regression analysis of quantitative variables, such as HVF mean deviation (MD), m-VEP discriminant score (Accumap Severity Index) and, global HRT parameters was also performed. m-VEP sensitivity and specificity were 93% and 96% respectively. HRT sensitivity and specificity were 79% and 92% respectively. The area under the receiver operating characteristic curve (ROC) for m-VEP was 0.96 and for HRT varied from 0.79 to 0.86 depending on the parameters used. Linear correlation between MD and Accumap Severity Index score was -77%, while that between HRT global parameters, Accumap Severity Index and MD were at best around 50%. Topographic comparison of the presence of scotoma on HVF and m-VEP in different areas of the visual field showed good agreement. Comparison of optic nerve head structural abnormality with corresponding areas of field defects on HVF and m-VEP showed poor to moderate agreement. The objective test of optic nerve function (m-VEP) and structure (HRT) can detect glaucomatous damage, with limited correlation. The 2 functional tests, HVF and m-VEP correlate better with each other than with HRT. It remains important to look for both functional and structural changes in order to detect all glaucoma cases.

  11. Accuracy of Linear Measurements Using Cone Beam Computed Tomography in Comparison with Clinical Measurements

    PubMed Central

    Rokn, Amir Reza; Hashemi, Kazem; Akbari, Solmaz; Kharazifard, Mohammad Javad; Barikani, Hamidreza; Panjnoosh, Mehrdad

    2016-01-01

    Objectives: This study sought to evaluate the accuracy and errors of linear measurements of mesiodistal dimensions of Kennedy Class III edentulous space using cone beam computed tomography (CBCT) in comparison with clinical measurements. Materials and Methods: Nineteen Kennedy Class III dental arches were evaluated. An impression was made of each dental arch and poured with dental stone. The distance was measured on dental cast using a digital Vernier caliper with an accuracy of 0.1mm and on CBCT scans. Finally, the linear mesiodistal measurements were compared and the accuracy of CBCT technique was evaluated by calculating absolute value of errors, intra-class correlation coefficient and simple linear regression model. Results: In comparison with the cast method, estimation of size on CBCT scans had an error of −8.46% (underestimation) to 5.21% (overestimation). In 26.5% of the cases, an accepted error of ±1% was found. The absolute value of errors was found to be in the range of 0.21–8.46mm with an average value of 2.86 ±2.30mm. Conclusions: Although the measurements revealed statistically significant differences, this does not indicate a lower accuracy for the CBCT technique. In fact, CBCT can provide some information as a paraclinical tool and the clinician can combine these data with clinical data and achieve greater accuracy. Undoubtedly, calibration of data collected by clinical and paraclinical techniques and the clinician’s expertise in use of CBCT software programs can increase the accuracy of implant placement. PMID:28127327

  12. Comparison of Compressed Sensing Algorithms for Inversion of 3-D Electrical Resistivity Tomography.

    NASA Astrophysics Data System (ADS)

    Peddinti, S. R.; Ranjan, S.; Kbvn, D. P.

    2016-12-01

    Image reconstruction algorithms derived from electrical resistivity tomography (ERT) are highly non-linear, sparse, and ill-posed. The inverse problem is much severe, when dealing with 3-D datasets that result in large sized matrices. Conventional gradient based techniques using L2 norm minimization with some sort of regularization can impose smoothness constraint on the solution. Compressed sensing (CS) is relatively new technique that takes the advantage of inherent sparsity in parameter space in one or the other form. If favorable conditions are met, CS was proven to be an efficient image reconstruction technique that uses limited observations without losing edge sharpness. This paper deals with the development of an open source 3-D resistivity inversion tool using CS framework. The forward model was adopted from RESINVM3D (Pidlisecky et al., 2007) with CS as the inverse code. Discrete cosine transformation (DCT) function was used to induce model sparsity in orthogonal form. Two CS based algorithms viz., interior point method and two-step IST were evaluated on a synthetic layered model with surface electrode observations. The algorithms were tested (in terms of quality and convergence) under varying degrees of parameter heterogeneity, model refinement, and reduced observation data space. In comparison to conventional gradient algorithms, CS was proven to effectively reconstruct the sub-surface image with less computational cost. This was observed by a general increase in NRMSE from 0.5 in 10 iterations using gradient algorithm to 0.8 in 5 iterations using CS algorithms.

  13. A comparison of sensors for minimizing the primary signal in planar-array magnetic induction tomography.

    PubMed

    Watson, S; Igney, C H; Dössel, O; Williams, R J; Griffiths, H

    2005-04-01

    In magnetic induction tomography reducing the influence of the primary excitation field on the sensors can provide a significant improvement in SNR and/or allow the operating frequency to be reduced. For the purposes of imaging, it would be valuable if all, or a useful subset, of the detection coils could be rendered insensitive to the primary field for any excitation coil activated. Suitable schemes which have been previously suggested include the use of axial gradiometers and coil-orientation methods (Bx sensors). This paper examines the relative performance of each method through computer simulation of the sensitivity profiles produced by a single sensor, and comparison of reconstructed images produced by sensor arrays. A finite-difference model was used to determine the sensitivity profiles obtained with each type of sensor arrangement. The modelled volume was a cuboid of dimensions 50 cmx50 cmx12 cm with a uniform conductivity of 1 S m-1. The excitation coils were of 5 cm diameter and the detection coils of 5 mm diameter. The Bx sensors provided greater sensitivity than the axial gradiometers at all depths, other than on the surface layer of the volume. Images produced using a single-planar array were found to contain distortion which was reduced by the addition of a second array.

  14. Different intravenous contrast media concentrations do not affect clinical assessment of 18F-fluorodeoxyglucose positron emission tomography/computed tomography scans in an intraindividual comparison.

    PubMed

    Prechtel, Hans W E; Verburg, Frederik A; Palmowski, Moritz; Krohn, Thomas; Pietsch, Hubertus; Kuhl, Christiane K; Mottaghy, Felix M; Behrendt, Florian F

    2012-09-01

    The purpose of this study was to perform an intraindividual comparison of the influences of different iodine contrast media on tracer uptake, contrast enhancement, and image quality in combined positron emission tomography (PET)/computed tomography (CT). Fifty-one patients underwent baseline and follow-up combined PET/CT consisting of low-dose unenhanced and venous contrast-enhanced CT with contrast media containing a high concentration of iodine (iopromide, 370 mg/mL) and a standard iodine concentration (iopromide, 300 mg/mL). The total iodine load (44.4 g) and the iodine delivery rate (1.29 g/s) were identical for the 2 protocols. The mean and maximum standard uptake values, as measures of tracer uptake and contrast enhancement for unenhanced and contrast-enhanced PET/CT, were quantified at 10 different anatomical sites, and images were analyzed for clinically relevant differences. The mean and maximum standard uptake values were significantly increased in contrast-enhanced PET/CT compared with unenhanced PET/CT at each anatomical site (P < 0.05). Comparison of tracer uptake between the 300- and 370-mg iodine contrast media showed no significant differences (all P > 0.05). Comparison of contrast enhancement between the 300- and 370-mg iodine contrast media showed no significant difference at any anatomical site (all P > 0.05). Analysis of image quality revealed no clinically relevant differences between the 2 different iodine contrast media (P = 0.739). The use of contrast-enhanced CT scans for attenuation correction in PET/CT does not cause clinically relevant artifacts in PET scan reconstruction, regardless of the iodine concentration used. Standard- and high-iodine contrast media can be used equivalently.

  15. Computerized Ultrasound Risk Evaluation (CURE): First Clinical Results

    NASA Astrophysics Data System (ADS)

    Duric, N.; Littrup, P.; Rama, O.; Holsapple, E.

    The Karmanos Cancer Institute has developed an ultrasound (US) tomography system, known as Computerized Ultrasound Risk Evaluation (CURE), for detecting and evaluating breast cancer, with the eventual goal of providing improved differentiation of benign masses from cancer. We report on our first clinical findings with CURE.

  16. Comparison of micro-computed tomography and laser scanning for reverse engineering orthopaedic component geometries.

    PubMed

    Teeter, Matthew G; Brophy, Paul; Naudie, Douglas D R; Holdsworth, David W

    2012-03-01

    A significant amount of research has been undertaken to evaluate the function of implanted joint replacement components. Many of these studies require the acquisition of an accurate three-dimensional geometric model of the various implant components, using methods such as micro-computed tomography or laser scanning. The purpose of this study was to compare micro-computed tomography and laser scanning for obtaining component geometries. Five never-implanted polyethylene tibial inserts of one type were scanned with both micro-computed tomography and laser scanning to determine the repeatability of each method and measured for any deviations between the geometries acquired from the different scans. Overall, good agreement was found between the micro-computed tomography and laser scans, to within 71 microm on average. Micro-computed tomography was found to have superior repeatability to laser scanning (mean of 1 microm for micro-computed tomography versus 19 microm for laser scans). Micro-computed tomography may be preferred for visualizing small surface features, whereas laser scanning may be preferred for acquiring the geometry of metal objects to avoid computed tomography artifacts. In conclusion, the choice of micro-computed tomography versus laser scanning for acquiring orthopaedic component geometries will likely involve considerations of user preference, the specific application the scan will be used for, and the availability of each system.

  17. Comparison of diffraction-enhanced computed tomography and monochromatic synchrotron radiation computed tomography of human trabecular bone.

    PubMed

    Connor, D M; Hallen, H D; Lalush, D S; Sumner, D R; Zhong, Z

    2009-10-21

    Diffraction-enhanced imaging (DEI) is an x-ray-based medical imaging modality that, when used in tomography mode (DECT), can generate a three-dimensional map of both the apparent absorption coefficient and the out-of-plane gradient of the index of refraction of the sample. DECT is known to have contrast gains over monochromatic synchrotron radiation CT (SRCT) for soft tissue structures. The goal of this experiment was to compare contrast-to-noise ratio (CNR) and resolution in images of human trabecular bone acquired using SRCT with images acquired using DECT. All images were acquired at the National Synchrotron Light Source (Upton, NY, USA) at beamline X15 A at an x-ray energy of 40 keV and the silicon [3 3 3] reflection. SRCT, apparent absorption DECT and refraction DECT slice images of the trabecular bone were created. The apparent absorption DECT images have significantly higher spatial resolution and CNR than the corresponding SRCT images. Thus, DECT will prove to be a useful tool for imaging applications in which high contrast and high spatial resolution are required for both soft tissue features and bone.

  18. Quantitative analysis of brain edema and swelling on early postmortem computed tomography: comparison with antemortem computed tomography.

    PubMed

    Takahashi, Naoya; Satou, Chihiro; Higuchi, Takeshi; Shiotani, Motoi; Maeda, Haruo; Hirose, Yasuo

    2010-06-01

    The aim of this study was quantitatively to analyze brain edema and swelling due to early postmortem changes using computed tomography (CT) scans of the head. Review board approval was obtained, and informed consent was waived. A total of 41 patients who underwent head CT before and shortly after death were enrolled. Hounsfield units (HUs) of gray matter (GM) and white matter (WM) were measured at the levels of the basal ganglia, centrum semiovale, and high convexity area on both antemortem and postmortem CT. The length of the minor axis of the third ventricle at the level of the basal ganglia and the width of the central sulcus at the level of high convexity were measured. At each level tested, the HUs of GM and the GM/WM ratios on postmortem CT were significantly lower than those on antemortem CT (P < 0.001). HUs of WM on postmortem CT were slightly higher than those on antemortem CT but without significant difference (P > 0.1). Postmortem CT showed subtle loss of distinction between GM and WM. The size of the third ventricle and the width of the central sulcus did not vary before and after death (P > 0.1). Early postmortem CT shows mild brain edema but does not show brain swelling.

  19. Comparisons of the diagnostic accuracies of optical coherence tomography, micro-computed tomography, and histology in periodontal disease: an ex vivo study

    PubMed Central

    2017-01-01

    Purpose Optical coherence tomography (OCT) is a noninvasive diagnostic technique that may be useful for both qualitative and quantitative analyses of the periodontium. Micro-computed tomography (micro-CT) is another noninvasive imaging technique capable of providing submicron spatial resolution. The purpose of this study was to present periodontal images obtained using ex vivo dental OCT and to compare OCT images with micro-CT images and histologic sections. Methods Images of ex vivo canine periodontal structures were obtained using OCT. Biologic depth measurements made using OCT were compared to measurements made on histologic sections prepared from the same sites. Visual comparisons were made among OCT, micro-CT, and histologic sections to evaluate whether anatomical details were accurately revealed by OCT. Results The periodontal tissue contour, gingival sulcus, and the presence of supragingival and subgingival calculus could be visualized using OCT. OCT was able to depict the surface topography of the dentogingival complex with higher resolution than micro-CT, but the imaging depth was typically limited to 1.2–1.5 mm. Biologic depth measurements made using OCT were a mean of 0.51 mm shallower than the histologic measurements. Conclusions Dental OCT as used in this study was able to generate high-resolution, cross-sectional images of the superficial portions of periodontal structures. Improvements in imaging depth and the development of an intraoral sensor are likely to make OCT a useful technique for periodontal applications. PMID:28261522

  20. Value of image fusion using single photon emission computed tomography with integrated low dose computed tomography in comparison with a retrospective voxel-based method in neuroendocrine tumours.

    PubMed

    Amthauer, H; Denecke, T; Rohlfing, T; Ruf, J; Böhmig, M; Gutberlet, M; Plöckinger, U; Felix, R; Lemke, A J

    2005-07-01

    The objective was the evaluation of single photon emission computed tomography (SPECT) with integrated low dose computed tomography (CT) in comparison with a retrospective fusion of SPECT and high-resolution CT and a side-by-side analysis for lesion localisation in patients with neuroendocrine tumours. Twenty-seven patients were examined by multidetector CT. Additionally, as part of somatostatin receptor scintigraphy (SRS), an integrated SPECT-CT was performed. SPECT and CT data were fused using software with a registration algorithm based on normalised mutual information. The reliability of the topographic assignment of lesions in SPECT-CT, retrospective fusion and side-by-side analysis was evaluated by two blinded readers. Two patients were not enrolled in the final analysis because of misregistrations in the retrospective fusion. Eighty-seven foci were included in the analysis. For the anatomical assignment of foci, SPECT-CT and retrospective fusion revealed overall accuracies of 91 and 94% (side-by-side analysis 86%). The correct identification of foci as lymph node manifestations (n=25) was more accurate by retrospective fusion (88%) than from SPECT-CT images (76%) or by side-by-side analysis (60%). Both modalities of image fusion appear to be well suited for the localisation of SRS foci and are superior to side-by-side analysis of non-fused images especially concerning lymph node manifestations.

  1. Participants' Reactions to Computerized Testing.

    ERIC Educational Resources Information Center

    Moe, Kim C.; Johnson, Marilyn F.

    This study investigated participants' reactions to computerized testing and assessed the practicability of this testing method in the classroom. A sample of 315 secondary-level students took a computerized and a printed version of a standardized aptitude test battery and a survey assessing their reactions to the computerized testing. Overall…

  2. Computerized Drug Information Services

    ERIC Educational Resources Information Center

    And Others; Smith, Daniel R.

    1972-01-01

    To compare computerized services in chemistry, pharmacology, toxicology, and clinical medicine of pharmaceutical interest, equivalent profiles were run on magnetic tape files of CA-Condensates," CBAC," Excerpta Medica," MEDLARS" and Ringdoc." The results are tabulated for overlap of services, relative speed of citing references, and unique…

  3. Computerized Drug Information Services

    ERIC Educational Resources Information Center

    And Others; Smith, Daniel R.

    1972-01-01

    To compare computerized services in chemistry, pharmacology, toxicology, and clinical medicine of pharmaceutical interest, equivalent profiles were run on magnetic tape files of CA-Condensates," CBAC," Excerpta Medica," MEDLARS" and Ringdoc." The results are tabulated for overlap of services, relative speed of citing references, and unique…

  4. Seven Myths of Computerism.

    ERIC Educational Resources Information Center

    Yeaman, Andrew R. J.

    1992-01-01

    Discussion of computerism (i.e., blind faith in the inherent good of computers) focuses on seven myths about computer anxiety, including the relationship between computer use and math skills; fear of breaking computers; the need for keyboarding skills; and gender differences. An annotated bibliography of 21 sources of further information is…

  5. Computerizing the Library.

    ERIC Educational Resources Information Center

    Chan, Jeanie; Whelan, Errol

    1988-01-01

    Discusses the development of a computerized high school library which uses CD-ROM optical storage systems. Describes hardware and software, setting up the system, preparing the online catalog, teaching information retrieval skills, and project evaluation. Notes prices of CD-ROM disks and equipment purchased. 4 references. (SV)

  6. The History Computerization Project.

    ERIC Educational Resources Information Center

    Clark, David L.

    1992-01-01

    Description of the History Computerization Project, which is being developed for the exchange of information between researchers, librarians, archivists, museum curators, preservation groups, and historical societies, focuses on workshops that teach the use of computer database management for historical cataloging and research. (LRW)

  7. Computerized Language Analysis.

    ERIC Educational Resources Information Center

    Ray, Steven

    1985-01-01

    The article describes a computerized language analysis system that produces a detailed description and summary statistics to track language growth within student populations. This microcomputer-based language assessment system simplifies identification of deficits in productive language, enabling the teacher or clinician to spend more time…

  8. Psychosocial Communication and Computerization.

    ERIC Educational Resources Information Center

    Bradley, Gunilla; And Others

    1993-01-01

    Discusses the effect of computerization of the work environment on psychosocial communication. The RAM program, developed at Stockholm University to explore the effect of computers on the structure of organizations and the psychosocial work environment, is described; theoretical models are explained; and the future use of knowledge-based systems…

  9. Computerized Cognition Laboratory.

    ERIC Educational Resources Information Center

    Motes, Michael A.; Wiegmann, Douglas A.

    1999-01-01

    Describes a software package entitled the "Computerized Cognition Laboratory" that helps integrate the teaching of cognitive psychology and research methods. Allows students to explore short-term memory, long-term memory, and decision making. Can also be used to teach the application of several statistical procedures. (DSK)

  10. Qualitative Comparison of Noncontrast Head Dual-Energy Computed Tomography Using Rapid Voltage Switching Technique and Conventional Computed Tomography.

    PubMed

    Hwang, William D; Mossa-Basha, Mahmud; Andre, Jalal B; Hippe, Daniel S; Culbertson, Scott; Anzai, Yoshimi

    2016-01-01

    Dual-energy computed tomography (DECT) allows image reconstruction along a spectrum of virtual monochromatic energy levels. We sought to determine the optimal energy level(s) for viewing supratentorial brain and posterior fossa and compare those to polychromatic conventional CT (CCT). Furthermore, we compared 2 groups scanned with separate DECT imaging protocols. In addition, we quantify the radiation dose of DECT versus CCT. Forty-four nonacute patients underwent noncontrast DECT and recent CCT on the same scanner. Dual-energy CT images of the head were reconstructed at 5 keV intervals from 50 to 100 keV and randomized with CCT for blinded reader analysis. Evaluation of gray-white matter differentiation, posterior fossa artifact, and overall image noise was performed in consensus using a 5-point scale. In addition, the CTDIvol was compared with CCT examinations. Optimal monochromatic viewing levels in evaluating gray-white matter differentiation were 50 to 55 keV and 50 to 60 keV, using regular-dose DECT (R-DECT) and low-dose DECT (L-DECT), respectively. The optimal levels for mitigating posterior fossa artifacts were 80 to 100 keV utilizing both R-DECT and L-DECT, whereas the optimal viewing levels for improved overall image noise were 60 to 65 keV and 65 to 70 keV for R-DECT and L-DECT, respectively. Readers favored both DECT techniques over CCT. The CTDIvol for DECT was 10% and 37% lower than CCT without a statistically significant reduction in image quality. Optimized noncontrast DECT compared favorably to CCT, with a significant dose reduction benefit.

  11. Chronic thromboembolic pulmonary hypertension: Comparison of dual-energy computed tomography and single photon emission computed tomography in canines.

    PubMed

    Tang, Chun Xiang; Yang, Gui Fen; Schoepf, U Joseph; Han, Zong Hong; Qi, Li; Zhao, Yan E; Wu, Jiang; Zhou, Chang Sheng; Zhu, Hong; Stubenrauch, Andrew C; Mangold, Stefanie; Zhang, Long Jiang; Lu, Guang Ming

    2016-02-01

    To compare diagnostic accuracy between dual-energy CT lung perfused blood volume (Lung PBV) imaging and single photon emission computed tomography (SPECT) in detecting chronic thromboembolic pulmonary hypertension (CTEPH) with histopathological results as reference standard in a canine model. Eighteen CTEPH canines were included into this experimental study. All procedures including paracentesis, embolization, scanning, pressure measurement and feeding medicine were repeated each two weeks, until systolic/diastolic pressure in canines was ≥ 30/15 mm Hg or mean pulmonary artery pressure ≥ 20 mm Hg, and then sacrificed for histopathology examination. Two radiologists (readers 1 and 2) and two nuclear radiologists (readers 3 and 4) analyzed images of conventional CT pulmonary angiography in dual-energy CT mode, Lung PBV imaging and SPECT, respectively. The presence, numbers, and locations of pulmonary emboli (PE) were recorded on a per-lobe basis. Pathological examination was served as reference standard. Sensitivity, specificity and accuracy of Lung PBV and SPECT were calculated. Kappa statistics were used to quantify inter-reader agreement. With histopathological results as reference standard, the sensitivities of 72.2%, 78.8%, 81.2%, specificities of 75.9%, 87.5%, 84.8%, accuracies of 73.8%, 83.1%, 83.1%, for readers 1, 2 and both with Lung PBV, respectively. Readers 3, 4 and both had sensitivities of 14.3%, 25.7%, 33.3%, specificities of 90.0%, 86.7%, 93.3%, accuracies of 49.2%, 53.8%, 60.0% with SPECT for detecting CTEPH. Inter-reader agreements were good for dual-energy CT (kappa=0.662) and SPECT (k=0.706) for detecting CTEPH. Dual-energy CT had a higher accuracy to detect CTEPH than SPECT in this canine model study. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Assessing apical transportation in curved canals: comparison between cross-sections and micro-computed tomography.

    PubMed

    Freire, Laila Gonzales; Gavini, Giulio; Cunha, Rodrigo Sanches; Santos, Marcelo dos

    2012-01-01

    The aim of this study was to compare two methods of assessing apical transportation in curved canals after rotary instrumentation, namely, cross-sections and micro-computed tomography (µCT). Thirty mandibular molars were divided into two groups and prepared according to the requirements of each method. In G1 (cross-sections), teeth were embedded in resin blocks and sectioned at 2.0, 3.5, and 5.0 mm from the anatomic apex. Pre- and postoperative sections were photographed and analyzed. In G2 (µCT), teeth were embedded in a rubber-base impression material and scanned before and after instrumentation. Mesiobuccal canals were instrumented with the Twisted File (TF) system (SybronEndo, Orange, USA), and mesiolingual canals, with the EndoSequence (ES) system (Brasseler, Savannah, USA). Images were reconstructed, and sections corresponding to distances 2.0, 3.5, and 5.0 mm from the anatomic apex were selected for comparison. Data were analyzed using Mann-Whitney's test at a 5% significance level. The TF and ES instruments produced little deviation from the root canal center, with no statistical difference between them (P > 0.05). The canal transportation results were significantly lower (0.056 mm) in G2 than in G1 (0.089 mm) (p = 0.0012). The µCT method was superior to the cross-section method, especially in view of its ability to preserve specimens and provide results that are more closely related to clinical situations.

  13. Structure-function relationships using spectral-domain optical coherence tomography: comparison with scanning laser polarimetry.

    PubMed

    Aptel, Florent; Sayous, Romain; Fortoul, Vincent; Beccat, Sylvain; Denis, Philippe

    2010-12-01

    To evaluate and compare the regional relationships between visual field sensitivity and retinal nerve fiber layer (RNFL) thickness as measured by spectral-domain optical coherence tomography (OCT) and scanning laser polarimetry. Prospective cross-sectional study. One hundred and twenty eyes of 120 patients (40 with healthy eyes, 40 with suspected glaucoma, and 40 with glaucoma) were tested on Cirrus-OCT, GDx VCC, and standard automated perimetry. Raw data on RNFL thickness were extracted for 256 peripapillary sectors of 1.40625 degrees each for the OCT measurement ellipse and 64 peripapillary sectors of 5.625 degrees each for the GDx VCC measurement ellipse. Correlations between peripapillary RNFL thickness in 6 sectors and visual field sensitivity in the 6 corresponding areas were evaluated using linear and logarithmic regression analysis. Receiver operating curve areas were calculated for each instrument. With spectral-domain OCT, the correlations (r(2)) between RNFL thickness and visual field sensitivity ranged from 0.082 (nasal RNFL and corresponding visual field area, linear regression) to 0.726 (supratemporal RNFL and corresponding visual field area, logarithmic regression). By comparison, with GDx-VCC, the correlations ranged from 0.062 (temporal RNFL and corresponding visual field area, linear regression) to 0.362 (supratemporal RNFL and corresponding visual field area, logarithmic regression). In pairwise comparisons, these structure-function correlations were generally stronger with spectral-domain OCT than with GDx VCC and with logarithmic regression than with linear regression. The largest areas under the receiver operating curve were seen for OCT superior thickness (0.963 ± 0.022; P < .001) in eyes with glaucoma and for OCT average thickness (0.888 ± 0.072; P < .001) in eyes with suspected glaucoma. The structure-function relationship was significantly stronger with spectral-domain OCT than with scanning laser polarimetry, and was better expressed

  14. Comparison of optical coherence tomography assessments in the comparison of age-related macular degeneration treatments trials.

    PubMed

    Folgar, Francisco A; Jaffe, Glenn J; Ying, Gui-Shuang; Maguire, Maureen G; Toth, Cynthia A

    2014-10-01

    To determine agreement between spectral-domain (SD) and time-domain (TD) optical coherence tomography (OCT) image assessments by certified readers in eyes treated for neovascular age-related macular degeneration (AMD). Cross-sectional study within the Comparison of AMD Treatments Trials (CATT). During year 2 of CATT, 1213 pairs of SD OCT and TD OCT scans were compared from a subset of 384 eyes. Masked readers independently graded OCT scans for presence of intraretinal fluid (IRF), subretinal fluid (SRF), and sub-retinal pigment epithelium (RPE) fluid and performed manual measurements of retinal, SRF, and subretinal tissue complex thicknesses at the foveal center. Presence of fluid was evaluated with percent agreement, κ coefficients with 95% confidence intervals (CIs), and McNemar tests. Thickness measurements were evaluated with mean difference (Δ) ±95% limits of agreement and intraclass correlation coefficients (ICCs) with 95% CIs. Between SD OCT and TD OCT, agreement on presence of any fluid was 82% (κ = 0.46; 95% CI, 0.40-0.52), with 5% more SD OCT scans demonstrating fluid (P<0.001). Agreement on presence of SRF was 87% and sub-RPE fluid was 80%, with more SD OCT scans demonstrating fluid (both P < 0.001). Agreement on IRF was 73% (κ = 0.47; 95% CI, 0.42-0.52), with 6% more TD OCT scans demonstrating fluid (P < 0.001). Between SD OCT and TD OCT, mean thickness of the retina was Δ = 5±67 μm, SRF was Δ = 1.5±35 μm, and subretinal tissue complex was Δ = 5±86 μm. Thickness measurements were reproducible for retina (ICC = 0.84; 95% CI, 0.83-0.86), SRF (ICC = 0.88; 95% CI, 0.86-0.89), and subretinal tissue complex (ICC = 0.91; 95% CI, 0.89-0.92), with ≤25-μm difference in these measurements in 71%, 94%, and 61% of paired scans, respectively. Agreement on fluid presence and manual thickness measurements between paired scans from each OCT modality was moderate, providing a reasonable basis to compare CATT results with future SD OCT-based trials. Fluid

  15. Comparison of a Novel Weightbearing Cone Beam Computed Tomography Scanner Versus a Conventional Computed Tomography Scanner for Measuring Patellar Instability

    PubMed Central

    Marzo, John; Kluczynski, Melissa; Notino, Anthony; Bisson, Leslie

    2016-01-01

    Background: Conventional computed tomography (CT) images are routinely used for diagnosing patellofemoral instability and are obtained with the patient in a supine position, nonweightbearing, with the knee in full extension, and with leg muscles relaxed. A new portable extremity cone beam CT (CBCT) scanner has been developed that may allow for more accurate diagnosis, as imaging can be performed with the patient standing, the knee flexed, and with leg muscles active. Purpose/Hypothesis: The purpose of this study was to compare CT measurements of patellar alignment on a prototype scanner versus conventional scanner in patients with known patellar instability. The hypothesis was that the measurements obtained with the knee flexed and the patient weightbearing would be less than those obtained from the conventional CT scan. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Twenty patients with a diagnosis of lateral patellar instability were imaged on both a conventional CT scanner and on a prototype CBCT scanner. Objective measures of patellofemoral alignment (tilt angle, congruence angle, tibial tuberosity–trochlear groove [TT-TG] offset) were assessed on images obtained from the prototype and conventional CT scans by 2 independent reviewers. Paired t tests were calculated to compare the mean measurement of patellofemoral alignment obtained from the prototype versus conventional CT. Interrater reliability was assessed using a 2-way mixed-effects model intraclass correlation coefficient (ICC) for tilt angle, congruence angle, and TT-TG offset on the prototype and conventional CT scans. Results: Measurements of patellofemoral alignment were significantly less when acquired by the new prototype CBCT scanner while subjects were weightbearing on a flexed knee. On the images from the prototype CBCT scan, the tilt angle averaged 18.2° ± 11.6° compared with 28.1° ± 7.1° on the conventional CT scan (P < .0001). The congruence angle was 3.0° ± 30

  16. LUNGx Challenge for computerized lung nodule classification

    DOE PAGES

    Armato, Samuel G.; Drukker, Karen; Li, Feng; ...

    2016-12-19

    The purpose of this work is to describe the LUNGx Challenge for the computerized classification of lung nodules on diagnostic computed tomography (CT) scans as benign or malignant and report the performance of participants’ computerized methods along with that of six radiologists who participated in an observer study performing the same Challenge task on the same dataset. The Challenge provided sets of calibration and testing scans, established a performance assessment process, and created an infrastructure for case dissemination and result submission. We present ten groups that applied their own methods to 73 lung nodules (37 benign and 36 malignant) thatmore » were selected to achieve approximate size matching between the two cohorts. Area under the receiver operating characteristic curve (AUC) values for these methods ranged from 0.50 to 0.68; only three methods performed statistically better than random guessing. The radiologists’ AUC values ranged from 0.70 to 0.85; three radiologists performed statistically better than the best-performing computer method. The LUNGx Challenge compared the performance of computerized methods in the task of differentiating benign from malignant lung nodules on CT scans, placed in the context of the performance of radiologists on the same task. Lastly, the continued public availability of the Challenge cases will provide a valuable resource for the medical imaging research community.« less

  17. LUNGx Challenge for computerized lung nodule classification

    SciTech Connect

    Armato, Samuel G.; Drukker, Karen; Li, Feng; Hadjiiski, Lubomir; Tourassi, Georgia D.; Engelmann, Roger M.; Giger, Maryellen L.; Redmond, George; Farahani, Keyvan; Kirby, Justin S.; Clarke, Laurence P.

    2016-12-19

    The purpose of this work is to describe the LUNGx Challenge for the computerized classification of lung nodules on diagnostic computed tomography (CT) scans as benign or malignant and report the performance of participants’ computerized methods along with that of six radiologists who participated in an observer study performing the same Challenge task on the same dataset. The Challenge provided sets of calibration and testing scans, established a performance assessment process, and created an infrastructure for case dissemination and result submission. We present ten groups that applied their own methods to 73 lung nodules (37 benign and 36 malignant) that were selected to achieve approximate size matching between the two cohorts. Area under the receiver operating characteristic curve (AUC) values for these methods ranged from 0.50 to 0.68; only three methods performed statistically better than random guessing. The radiologists’ AUC values ranged from 0.70 to 0.85; three radiologists performed statistically better than the best-performing computer method. The LUNGx Challenge compared the performance of computerized methods in the task of differentiating benign from malignant lung nodules on CT scans, placed in the context of the performance of radiologists on the same task. Lastly, the continued public availability of the Challenge cases will provide a valuable resource for the medical imaging research community.

  18. LUNGx Challenge for computerized lung nodule classification.

    PubMed

    Armato, Samuel G; Drukker, Karen; Li, Feng; Hadjiiski, Lubomir; Tourassi, Georgia D; Engelmann, Roger M; Giger, Maryellen L; Redmond, George; Farahani, Keyvan; Kirby, Justin S; Clarke, Laurence P

    2016-10-01

    The purpose of this work is to describe the LUNGx Challenge for the computerized classification of lung nodules on diagnostic computed tomography (CT) scans as benign or malignant and report the performance of participants' computerized methods along with that of six radiologists who participated in an observer study performing the same Challenge task on the same dataset. The Challenge provided sets of calibration and testing scans, established a performance assessment process, and created an infrastructure for case dissemination and result submission. Ten groups applied their own methods to 73 lung nodules (37 benign and 36 malignant) that were selected to achieve approximate size matching between the two cohorts. Area under the receiver operating characteristic curve (AUC) values for these methods ranged from 0.50 to 0.68; only three methods performed statistically better than random guessing. The radiologists' AUC values ranged from 0.70 to 0.85; three radiologists performed statistically better than the best-performing computer method. The LUNGx Challenge compared the performance of computerized methods in the task of differentiating benign from malignant lung nodules on CT scans, placed in the context of the performance of radiologists on the same task. The continued public availability of the Challenge cases will provide a valuable resource for the medical imaging research community.

  19. Computed Tomography Number Measurement Consistency Under Different Beam Hardening Conditions: Comparison Between Dual-Energy Spectral Computed Tomography and Conventional Computed Tomography Imaging in Phantom Experiment.

    PubMed

    He, Tian; Qian, Xiaojun; Zhai, Renyou; Yang, Zongtao

    2015-01-01

    To compare computed tomography (CT) number measurement consistency under different beam hardening conditions in phantom experiment between dual-energy spectral CT and conventional CT imaging. A phantom with 8 cells in periphery region and 1 cell in central region were used. The 8 conditioning tubes in the periphery region were filled with 1 of the 3 iodine solutions to simulate different beam hardening conditions: 0 for no beam hardening (NBH), 20 mg/mL for weak beam hardening (WBH) and 50 mg/mL for severe beam hardening (SBH) condition. Test tube filled with 0, 0.1, 0.5, 1, 2, 5, 10, 20, and 50 mg/mL iodine solution was placed in the central cell alternately. The phantom was scanned with conventional CT mode with 80, 100, 120, and 140 kVp and dual energy spectral CT mode. For spectral CT, 11 monochromatic image sets from 40 to 140 keV with interval of 10 keV were reconstructed. The CT number shift caused by beam hardening was evaluated by measuring the CT number difference (ΔCT) with and without beam hardening, with the following formulas: ΔCTWBH = |CTWBH - CTNBH| and ΔCTSBH = |CTSBH - CTNBH|. Data were compared with 1-way analysis of variance. Under both WBH and SBH conditions, the CT number shifts in all monochromatic image sets were less than those for polychromatic images (all P < 0.001). Under WBH condition, the maximum CT number shift was less than 6 Hounsfield units for monochromatic spectral CT images of all energy levels; under SBH condition, only monochromatic images at 70 keV and 80 keV had CT number shift less than 6 HU. Dual energy spectral CT imaging provided more accurate CT number measurement than conventional CT under various beam hardening conditions. The optimal keV level for monochromatic spectral CT images with the most accurate CT number measurement depends on the severities of beam hardening condition.

  20. Computed Tomography Number Measurement Consistency Under Different Beam Hardening Conditions: Comparison Between Dual-Energy Spectral Computed Tomography and Conventional Computed Tomography Imaging in Phantom Experiment

    PubMed Central

    He, Tian; Qian, Xiaojun; Zhai, Renyou; Yang, Zongtao

    2015-01-01

    Purpose To compare computed tomography (CT) number measurement consistency under different beam hardening conditions in phantom experiment between dual-energy spectral CT and conventional CT imaging. Materials and Methods A phantom with 8 cells in periphery region and 1 cell in central region were used. The 8 conditioning tubes in the periphery region were filled with 1 of the 3 iodine solutions to simulate different beam hardening conditions: 0 for no beam hardening (NBH), 20 mg/mL for weak beam hardening (WBH) and 50 mg/mL for severe beam hardening (SBH) condition. Test tube filled with 0, 0.1, 0.5, 1, 2, 5, 10, 20, and 50 mg/mL iodine solution was placed in the central cell alternately. The phantom was scanned with conventional CT mode with 80, 100, 120, and 140 kVp and dual energy spectral CT mode. For spectral CT, 11 monochromatic image sets from 40 to 140 keV with interval of 10 keV were reconstructed. The CT number shift caused by beam hardening was evaluated by measuring the CT number difference (ΔCT) with and without beam hardening, with the following formulas: ΔCTWBH = |CTWBH − CTNBH| and ΔCTSBH = |CTSBH − CTNBH|. Data were compared with 1-way analysis of variance. Results Under both WBH and SBH conditions, the CT number shifts in all monochromatic image sets were less than those for polychromatic images (all P < 0.001). Under WBH condition, the maximum CT number shift was less than 6 Hounsfield units for monochromatic spectral CT images of all energy levels; under SBH condition, only monochromatic images at 70 keV and 80 keV had CT number shift less than 6 HU. Conclusion Dual energy spectral CT imaging provided more accurate CT number measurement than conventional CT under various beam hardening conditions. The optimal keV level for monochromatic spectral CT images with the most accurate CT number measurement depends on the severities of beam hardening condition. PMID:26196347

  1. Computerized operating procedures

    SciTech Connect

    Ness, E.; Teigen, J.

    1994-12-31

    A number of observed and potential problems in the nuclear industry are related to the quality of operating procedures. Many of the problems identified in operating procedure preparation, implementation, and maintenance have a technical nature, which can be directly addressed by developing computerized procedure handling tools. The Halden Reactor Project (HRP) of the Organization for Economic Cooperation and Development has since 1985 performed research work within this field. A product of this effort is the development of a second version of the computerized operation manuals (COPMA) system. This paper summarizes the most important characteristics of the COPMA-II system and discusses some of the experiences in using a system like COPMA-II.

  2. Computerizing Audit Studies.

    PubMed

    Lahey, Joanna N; Beasley, Ryan A

    2009-06-01

    This paper briefly discusses the history, benefits, and shortcomings of traditional audit field experiments to study market discrimination. Specifically it identifies template bias and experimenter bias as major concerns in the traditional audit method, and demonstrates through an empirical example that computerization of a resume or correspondence audit can efficiently increase sample size and greatly mitigate these concerns. Finally, it presents a useful meta-tool that future researchers can use to create their own resume audits.

  3. Computerizing Audit Studies

    PubMed Central

    Lahey, Joanna N.; Beasley, Ryan A.

    2014-01-01

    This paper briefly discusses the history, benefits, and shortcomings of traditional audit field experiments to study market discrimination. Specifically it identifies template bias and experimenter bias as major concerns in the traditional audit method, and demonstrates through an empirical example that computerization of a resume or correspondence audit can efficiently increase sample size and greatly mitigate these concerns. Finally, it presents a useful meta-tool that future researchers can use to create their own resume audits. PMID:24904189

  4. Comparison of Cone Beam Computed Tomography and Multi Slice Computed Tomography Image Quality of Human Dried Mandible using 10 Anatomical Landmarks

    PubMed Central

    Saati, Samira; Kaveh, Fatemeh

    2017-01-01

    Introduction Cone Beam Computed Tomography (CBCT) has gained a broad acceptance in dentomaxillofacial imaging. Computed Tomography (CT) is another imaging modality for diagnosis and preoperative assessments of the head and neck region. Aim Considering the increased radiation exposure and high cost of CT, this study sought to subjectively assess the image quality of CBCT and Multi Slice CT (MSCT). Materials and Methods A dry human mandible was scanned by five CBCT systems (New Tom 3G, Scanora, CRANEX 3D, Promax and Galileos) and one MSCT system. Three independent oral and maxillofacial radiologists reviewed the CBCT and MSCT scans for the quality of 10 landmarks namely mental foramen, trabecular bone, Periodontal Ligament (PDL), dentin, incisive canal, mandibular canal, dental pulp, enamel, lamina dura and cortical bone using a five-point scale. Results Significant differences were found between MSCT and CBCT and among the five CBCT systems (p<0.05) in visualization of different anatomical structures. A fine structure such as the incisive canal was significantly less visible and more variable among the systems in comparison with other anatomical landmarks such as the mental foramen, mandibular canal, cortical bone, dental pulp, enamel and dentin (p<0.05). The Cranex 3D and Promax systems were superior to MSCT and all other CBCT systems in visualizing anatomical structures. Conclusion The CBCT image quality was superior to that of MSCT even though some variability existed among different CBCT systems in visualizing fine structures. Considering the low radiation dose and high resolution, CBCT may be beneficial for dentomaxillofacial imaging. PMID:28384972

  5. Comparison of low- and ultralow-dose computed tomography protocols for quantitative lung and airway assessment.

    PubMed

    Hammond, Emily; Sloan, Chelsea; Newell, John D; Sieren, Jered P; Saylor, Melissa; Vidal, Craig; Hogue, Shayna; De Stefano, Frank; Sieren, Alexa; Hoffman, Eric A; Sieren, Jessica C

    2017-09-01

    Quantitative computed tomography (CT) measures are increasingly being developed and used to characterize lung disease. With recent advances in CT technologies, we sought to evaluate the quantitative accuracy of lung imaging at low- and ultralow-radiation doses with the use of iterative reconstruction (IR), tube current modulation (TCM), and spectral shaping. We investigated the effect of five independent CT protocols reconstructed with IR on quantitative airway measures and global lung measures using an in vivo large animal model as a human subject surrogate. A control protocol was chosen (NIH-SPIROMICS + TCM) and five independent protocols investigating TCM, low- and ultralow-radiation dose, and spectral shaping. For all scans, quantitative global parenchymal measurements (mean, median and standard deviation of the parenchymal HU, along with measures of emphysema) and global airway measurements (number of segmented airways and pi10) were generated. In addition, selected individual airway measurements (minor and major inner diameter, wall thickness, inner and outer area, inner and outer perimeter, wall area fraction, and inner equivalent circle diameter) were evaluated. Comparisons were made between control and target protocols using difference and repeatability measures. Estimated CT volume dose index (CTDIvol) across all protocols ranged from 7.32 mGy to 0.32 mGy. Low- and ultralow-dose protocols required more manual editing and resolved fewer airway branches; yet, comparable pi10 whole lung measures were observed across all protocols. Similar trends in acquired parenchymal and airway measurements were observed across all protocols, with increased measurement differences using the ultralow-dose protocols. However, for small airways (1.9 ± 0.2 mm) and medium airways (5.7 ± 0.4 mm), the measurement differences across all protocols were comparable to the control protocol repeatability across breath holds. Diameters, wall thickness, wall area fraction

  6. Blow-out fractures of the orbit: a comparison of computed tomography and conventional radiography with anatomic correlation

    SciTech Connect

    Hammeschlag, S.B.; Hughes, S.; O'Reilly, G.V.; Naheedy, M.H.; Rumbaugh, C.L.

    1982-05-01

    Orbital blow-out fractures were experimentally created in eight human cadavers. Each orbit underwent conventional radiographic studies, complex motion tomography, and computed tomographic examinations. A comparison of the three modalities was made. Anatomical correlation was obtained by dissecting the orbits. The significance of medial-wall fractures and enophthalmos is discussed. Limitation of inferior rectus muscle mobility is thought to be a result of muscle kinking associated with orbital fat-pad prolapse at the fracture site, rather than muscle incarceration. Blow-out fractures should be evaluated by computed tomographic computer reformations in the oblique sagittal plane.

  7. Prospective comparison of computed tomography, diffusion-weighted magnetic resonance imaging and [11C]choline positron emission tomography/computed tomography for preoperative lymph node staging in prostate cancer patients.

    PubMed

    Heck, Matthias M; Souvatzoglou, Michael; Retz, Margitta; Nawroth, Roman; Kübler, Hubert; Maurer, Tobias; Thalgott, Mark; Gramer, Bettina M; Weirich, Gregor; Rondak, Ina-Christine; Rummeny, Ernst J; Schwaiger, Markus; Gschwend, Jürgen E; Krause, Bernd; Eiber, Matthias

    2014-04-01

    The aim of this study was to prospectively compare diffusion-weighted magnetic resonance imaging (DWI) and [(11)C]choline positron emission tomography/computed tomography (PET/CT) with computed tomography (CT) for preoperative lymph node (LN) staging in prostate cancer (PCa) patients. Between June 2010 and May 2012, CT, DWI and [(11)C]choline PET/CT were performed preoperatively in 33 intermediate- and high-risk PCa patients undergoing radical prostatectomy (RP) and extended pelvic lymph node dissection (ePLND) including obturator fossa and internal, external and common iliac fields. Patient- and field-based performance characteristics for all three imaging techniques based on histopathological results are reported. Imaging techniques were compared by means of the area under the curve (AUC). LN metastases were detected in 92 of 1,012 (9%) LNs from 14 of 33 (42%) patients. On patient-based analysis, sensitivity, specificity and accuracy for CT were 57, 68 and 64%, respectively, for DWI were 57, 79 and 70%, respectively, and for [(11)C]choline PET/CT were 57, 90 and 76%, respectively. On field-based analysis, these numbers for CT were 47, 94 and 88%, respectively, for DWI were 56, 97 and 92%, respectively, and for [(11)C]choline PET/CT were 62, 96 and 92%, respectively. Neither DWI nor [(11)C]choline PET/CT performed significantly better than CT on pairwise comparison of patient- and field-based results. All three imaging techniques exhibit a rather low sensitivity with less than two thirds of LN metastases being detected on patient- and field-based analysis. Overall diagnostic efficacy did not differ significantly between imaging techniques, whereas distinct performance characteristics, esp. patient-based specificity, were best for [(11)C]choline PET/CT followed by DWI and CT.

  8. Retrospective comparison of Computed Tomography Enterography and Magnetic Resonance Enterography in diagnosing small intestine disease.

    PubMed

    Pei-You, Gong; Jun-Xia, Li; Feng-Li, Liu; Liang-Ming, Zhang; Hai-Zhu, Xie; Yan-Bin, Sui

    2015-07-01

    To compare the efficacy of computed tomography enterography and magnetic resonance enterography in diagnosing small intestinal diseases. The retrospective study comparing computed tomography enterography and magnetic resonance enterography for diagnosing diseases related to small intestine was conducted at Department of Radiology, Yantai Yuhuangding Hospital, Shandong, China, from July 2012 to February 2014. The efficacy of computed tomography enterography and magnetic resonance enterography results were evaluated for randomly-selected cases to compare the location and characteristics of small intestinal diseases together with small bowel endoscopy and clinical pathology observations. Of the 30 patients in the study, 19(63.3%) were males and 11 (36.7%) were females with an overall mean age of 33.6±19.2 years (range: 24-67 years). the clinical diagnostic accuracy of computed tomography enterography and magnetic resonance enterography was 24(80%) and 21(70%) cases respectively (p>0.05). Computed tomography enterography and magnetic resonance enterography are two techniques that complement each other for diagnostic purposes.

  9. Comparison of hydraulic tomography with traditional methods at a highly heterogeneous site.

    PubMed

    Berg, Steven J; Illman, Walter A

    2015-01-01

    Over the past several decades, different groundwater modeling approaches of various complexities and data use have been developed. A recently developed approach for mapping hydraulic conductivity (K) and specific storage (Ss ) heterogeneity is hydraulic tomography, the performance of which has not been compared to other more "traditional" methods that have been utilized over the past several decades. In this study, we compare seven methods of modeling heterogeneity which are (1) kriging, (2) effective parameter models, (3) transition probability/Markov Chain geostatistics models, (4) geological models, (5) stochastic inverse models conditioned to local K data, (6) hydraulic tomography, and (7) hydraulic tomography conditioned to local K data using data collected in five boreholes at a field site on the University of Waterloo (UW) campus, in Waterloo, Ontario, Canada. The performance of each heterogeneity model is first assessed during model calibration. In particular, the correspondence between simulated and observed drawdowns is assessed using the mean absolute error norm, (L1 ), mean square error norm (L2 ), and correlation coefficient (R) as well as through scatterplots. We also assess the various models on their ability to predict drawdown data not used in the calibration effort from nine pumping tests. Results reveal that hydraulic tomography is best able to reproduce these tests in terms of the smallest discrepancy and highest correlation between simulated and observed drawdowns. However, conditioning of hydraulic tomography results with permeameter K data caused a slight deterioration in accuracy of drawdown predictions which suggests that data integration may need to be conducted carefully.

  10. Positron Emission Tomography/Magnetic Resonance Imaging for Local Tumor Staging in Patients With Primary Breast Cancer: A Comparison With Positron Emission Tomography/Computed Tomography and Magnetic Resonance Imaging.

    PubMed

    Grueneisen, Johannes; Nagarajah, James; Buchbender, Christian; Hoffmann, Oliver; Schaarschmidt, Benedikt Michael; Poeppel, Thorsten; Forsting, Michael; Quick, Harald H; Umutlu, Lale; Kinner, Sonja

    2015-08-01

    This study aimed to assess the diagnostic performance of integrated positron emission tomography (PET)/magnetic resonance imaging (MRI) of the breast for lesion detection and local tumor staging of patients with primary breast cancer in comparison to PET/computed tomography (CT) and MRI. The study was approved by the local institutional review board. Forty-nine patients with biopsy-proven invasive breast cancer were prospectively enrolled in our study. All patients underwent a PET/CT, and subsequently, a contrast-enhanced PET/MRI of the breast after written informed consent was obtained before each examination. Two radiologists independently evaluated the corresponding data sets (PET/CT, PET/MRI, and MRI) and were instructed to identify primary tumors lesions as well as multifocal/multicentric and bilateral disease. Furthermore, the occurrence of lymph node metastases was assessed, and the T-stage for each patient was determined. Histopathological verification of the local tumor extent and the axillary lymph node status was available for 30 of 49 and 48 of 49 patients, respectively. For the remaining patients, a consensus characterization was performed for the determination of the T-stage and nodal status, taking into account the results of clinical staging, PET/CT, and PET/MRI examinations. Statistical analysis was performed to test for differences in diagnostic performance between the different imaging procedures. P values less than 0.05 were considered to be statistically significant. Positron emission tomography/MRI and MRI correctly identified 47 (96%) of the 49 patients with primary breast cancer, whereas PET/CT enabled detection of 46 (94%) of 49 breast cancer patients and missed a synchronous carcinoma in the contralateral breast in 1 patient. In a lesion-by-lesion analysis, no significant differences could be obtained between the 3 imaging procedures for the identification of primary breast cancer lesions (P > 0.05). Positron emission tomography/MRI and

  11. Comparison of Positron Emission Tomography Quantification Using Magnetic Resonance- and Computed Tomography-Based Attenuation Correction in Physiological Tissues and Lesions: A Whole-Body Positron Emission Tomography/Magnetic Resonance Study in 66 Patients.

    PubMed

    Seith, Ferdinand; Gatidis, Sergios; Schmidt, Holger; Bezrukov, Ilja; la Fougère, Christian; Nikolaou, Konstantin; Pfannenberg, Christina; Schwenzer, Nina

    2016-01-01

    Attenuation correction (AC) in fully integrated positron emission tomography (PET)/magnetic resonance (MR) systems plays a key role for the quantification of tracer uptake. The aim of this prospective study was to assess the accuracy of standardized uptake value (SUV) quantification using MR-based AC in direct comparison with computed tomography (CT)-based AC of the same PET data set on a large patient population. Sixty-six patients (22 female; mean [SD], 61 [11] years) were examined by means of combined PET/CT and PET/MR (11C-choline, 18F-FDG, or 68Ga-DOTATATE) subsequently. Positron emission tomography images from PET/MR examinations were corrected with MR-derived AC based on tissue segmentation (PET(MR)). The same PET data were corrected using CT-based attenuation maps (μ-maps) derived from PET/CT after nonrigid registration of the CT to the MR-based μ-map (PET(MRCT)). Positron emission tomography SUVs were quantified placing regions of interest or volumes of interest in 6 different body regions as well as PET-avid lesions, respectively. The relative differences of quantitative PET values when using MR-based AC versus CT-based AC were varying depending on the organs and body regions assessed. In detail, the mean (SD) relative differences of PET SUVs were as follows: -7.8% (11.5%), blood pool; -3.6% (5.8%), spleen; -4.4% (5.6%)/-4.1% (6.2%), liver; -0.6% (5.0%), muscle; -1.3% (6.3%), fat; -40.0% (18.7%), bone; 1.6% (4.4%), liver lesions; -6.2% (6.8%), bone lesions; and -1.9% (6.2%), soft tissue lesions. In 10 liver lesions, distinct overestimations greater than 5% were found (up to 10%). In addition, overestimations were found in 2 bone lesions and 1 soft tissue lesion adjacent to the lung (up to 28.0%). Results obtained using different PET tracers show that MR-based AC is accurate in most tissue types, with SUV deviations generally of less than 10%. In bone, however, underestimations can be pronounced, potentially leading to inaccurate SUV quantifications. In

  12. Inter-scan variability of coronary artery calcium scoring assessed on 64-multidetector computed tomography vs. dual-source computed tomography: a head-to-head comparison.

    PubMed

    Ghadri, Jelena R; Goetti, Robert; Fiechter, Michael; Pazhenkottil, Aju P; Küest, Silke M; Nkoulou, Rene N; Windler, Christina; Buechel, Ronny R; Herzog, Bernhard A; Gaemperli, Oliver; Templin, Christian; Kaufmann, Philipp A

    2011-08-01

    Coronary artery calcium (CAC) scoring has emerged as a tool for risk stratification and potentially for monitoring response to risk factor modification. Therefore, repeat measurements should provide robust results and low inter-scanner variability for allowing meaningful comparison. The purpose of this study was to investigate inter-scanner variability of CAC for Agatston, volume, and mass scores by head-to-head comparison using two different cardiac computed tomography scanners: 64-detector multislice CT (MSCT) and 64-slice dual-source CT (DSCT). Thirty patients underwent CAC measurements on both 64-MSCT (GE LightSpeed XT scanner: 120 kV, 70 mAs, 2.5 mm slices) and 64-DSCT (Siemens Somatom Definition: 120 kV, 80 mAs, 3 mm slices) within <100 days (0-97). Retrospective intra-scan comparison revealed an excellent correlation. The excellent intra-scan (inter-observer) agreement was documented by narrow limits of agreement and a correlation coefficient of variation (COV) of r ≥ 0.99 (P < 0.001) for all CAC scores with a low COV for both scanners (64-MSCT/64-DSCT), i.e. Agatston (2.0/2.1%), mass (3.0/2.0%), and volume (4.7/3.9%). Inter-scanner comparison revealed larger Bland-Altman (BA) limits of agreement, despite high correlation (r ≥ 0.97) for all scores, with COV at 15.1, 21.6, and 44.9% for Agatston, mass, and volume scores. The largest BA limits were observed for volume scores (-1552.8 to 574.2), which was massively improved (-241.0 to 300.4, COV 11.5%) after reanalysing the 64-DSCT scans (Siemens) with GE software/workstation (while Siemens software/workstation does not allow cross-vendor analysis). Phantom measurements confirmed overestimation of volume scores by 'syngo Ca-Scoring' (Siemens) software which should therefore be reviewed (vendor has been notified). Intra- and inter-scan agreement of CAC measurement in a given data set is excellent. Inter-scanner variability is reasonable, particularly for Agatston units in the clinically most relevant range

  13. Small-angle scatter tomography with a photon-counting detector array

    NASA Astrophysics Data System (ADS)

    Pang, Shuo; Zhu, Zheyuan; Wang, Ge; Cong, Wenxiang

    2016-05-01

    Small-angle x-ray scatter imaging has a high intrinsic contrast in cancer research and other applications, and provides information on molecular composition and micro-structure of the tissue. In general, the implementations of small-angle coherent scatter imaging can be divided into two main categories: direct tomography and angular dispersive computerized tomography. Based on the recent development of energy-discriminative photon-counting detector array, here we propose a computerized tomography setup based on energy-dispersive measurement with a photon-counting detector array. To show merits of the energy-dispersive approach, we have performed numerical tests with a phantom containing various tissue types, in comparison with the existing imaging approaches. The results show that with an energy resolution of ~6 keV, the energy dispersive tomography system with a broadband tabletop x-ray would outperform the angular dispersive system, which makes the x-ray small-angle scatter tomography promising for high-specificity tissue imaging.

  14. Comparison of Computed Tomography and Chest Radiography in the Detection of Rib Fractures in Abused Infants

    ERIC Educational Resources Information Center

    Wootton-Gorges, Sandra L.; Stein-Wexler, Rebecca; Walton, John W.; Rosas, Angela J.; Coulter, Kevin P.; Rogers, Kristen K.

    2008-01-01

    Purpose: Chest radiographs (CXR) are the standard method for evaluating rib fractures in abused infants. Computed tomography (CT) is a sensitive method to detect rib fractures. The purpose of this study was to compare CT and CXR in the evaluation of rib fractures in abused infants. Methods: This retrospective study included all 12 abused infants…

  15. Comparison of Computed Tomography and Chest Radiography in the Detection of Rib Fractures in Abused Infants

    ERIC Educational Resources Information Center

    Wootton-Gorges, Sandra L.; Stein-Wexler, Rebecca; Walton, John W.; Rosas, Angela J.; Coulter, Kevin P.; Rogers, Kristen K.

    2008-01-01

    Purpose: Chest radiographs (CXR) are the standard method for evaluating rib fractures in abused infants. Computed tomography (CT) is a sensitive method to detect rib fractures. The purpose of this study was to compare CT and CXR in the evaluation of rib fractures in abused infants. Methods: This retrospective study included all 12 abused infants…

  16. Computerized procedures system

    DOEpatents

    Lipner, Melvin H.; Mundy, Roger A.; Franusich, Michael D.

    2010-10-12

    An online data driven computerized procedures system that guides an operator through a complex process facility's operating procedures. The system monitors plant data, processes the data and then, based upon this processing, presents the status of the current procedure step and/or substep to the operator. The system supports multiple users and a single procedure definition supports several interface formats that can be tailored to the individual user. Layered security controls access privileges and revisions are version controlled. The procedures run on a server that is platform independent of the user workstations that the server interfaces with and the user interface supports diverse procedural views.

  17. Myocardial ischemia evaluation with dual-source computed tomography: comparison with magnetic resonance imaging.

    PubMed

    Delgado, Carlos; Vázquez, María; Oca, Roque; Vilar, Manuel; Trinidad, Carmen; Sanmartin, Marcelo

    2013-11-01

    Computed tomography does not accurately determine which coronary lesions lead to myocardial ischemia and consequently further tests are required to evaluate ischemia induction. The aim of this study was to compare diagnostic accuracy between dual-energy computed tomography and magnetic resonance imaging in the assessment of myocardial perfusion and viability in patients suspected of coronary artery disease. A prospective study was performed in 56 consecutive patients (39 men [69.6%]; mean age [standard deviation], 63 [10]; range, 23-81). Computed tomography was performed with the following protocol: 1, adenosine stress perfusion; 2, coronary angiography; and 3, delayed enhancement. Magnetic resonance imaging for the evaluation of stress perfusion and delayed enhancement was performed within 30 days. Two observers in consensus analyzed the perfusion and delayed enhancement images. We studied 952 myocardial segments and 168 vascular territories. In a per-segment analysis, the sensitivity, specificity, and positive and negative predictive values of computed tomography compared with magnetic resonance were 76%, 99%, 89%, and 98% for perfusion defects, and 64%, 99%, 82%, and 99% for delayed enhancement, respectively. In a per-vascular territory analysis, the same measures were 78%, 97%, 86%, and 95% for perfusion defects, and 72%, 99%, 93%, and 97% for delayed enhancement, respectively. The mean radiation dose was 8.2 (2) mSv. Dual-source computed tomography may allow accurate and concomitant evaluation of perfusion defects and myocardial viability and analysis of coronary anatomy. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  18. Computed Tomography Status

    DOE R&D Accomplishments Database

    Hansche, B. D.

    1983-01-01

    Computed tomography (CT) is a relatively new radiographic technique which has become widely used in the medical field, where it is better known as computerized axial tomographic (CAT) scanning. This technique is also being adopted by the industrial radiographic community, although the greater range of densities, variation in samples sizes, plus possible requirement for finer resolution make it difficult to duplicate the excellent results that the medical scanners have achieved.

  19. Computed tomography status

    SciTech Connect

    Hansche, B.D.

    1983-01-01

    Computed tomography (CT) is a relatively new radiographic technique which has become widely used in the medical field, where it is better known as computerized axial tomographic (CAT) scanning. This technique is also being adopted by the industrial radiographic community, although the greater range of densities, variation in samples sizes, plus possible requirement for finer resolution make it difficult to duplicate the excellent results that the medical scanners have achieved.

  20. Comparison of optic area measurement using fundus photography and optical coherence tomography between optic nerve head drusen and control subjects.

    PubMed

    Flores-Rodríguez, Patricia; Gili, Pablo; Martín-Ríos, María Dolores; Grifol-Clar, Eulalia

    2013-03-01

    To compare optic disc area measurement between optic nerve head drusen (ONHD) and control subjects using fundus photography, time-domain optical coherence tomography (TD-OCT) and spectral-domain optical coherence tomography (SD-OCT). We also made a comparison between each of the three techniques. We performed our study on 66 eyes (66 patients) with ONHD and 70 healthy control subjects (70 controls) with colour ocular fundus photography at 20º (Zeiss FF 450 IR plus), TD-OCT (Stratus OCT) with the Fast Optic Disc protocol and SD-OCT (Cirrus OCT) with the Optic Disc Cube 200 × 200 protocol for measurement of the optic disc area. The measurements were made by two observers and in each measurement a correction of the image magnification factor was performed. Measurement comparison using the Student's t-test/Mann-Whitney U test, the intraclass correlation coefficient, Pearson/Spearman rank correlation coefficient and the Bland-Altman plot was performed in the statistical analysis. Mean and standard deviation (SD) of the optic disc area in ONHD and in controls was 2.38 (0.54) mm(2) and 2.54 (0.42) mm(2), respectively with fundus photography; 2.01 (0.56) mm(2) and 1.66 (0.37) mm(2), respectively with TD-OCT, and 2.03 (0.49) mm(2) and 1.75 (0.38) mm(2), respectively with SD-OCT. In ONHD and controls, repeatability of optic disc area measurement was excellent with fundus photography and optical coherence tomography (TD-OCT and SD-OCT), but with a low degree of agreement between both techniques. Optic disc area measurement is smaller in ONHD compared to healthy subjects with fundus photography, unlike time-domain and spectral-domain optical coherence tomography in which the reverse is true. Both techniques offer good repeatability, but a low degree of correlation and agreement, which means that optic disc area measurement is not interchangeable or comparable between techniques. Ophthalmic & Physiological Optics © 2013 The College of Optometrists.

  1. 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.

  2. Implementation and comparison of reconstruction algorithms for two-dimensional optoacoustic tomography using a linear array

    NASA Astrophysics Data System (ADS)

    Modgil, Dimple; La Rivière, Patrick J.

    2009-07-01

    Our goal is to compare and contrast various image reconstruction algorithms for optoacoustic tomography (OAT) assuming a finite linear aperture of the kind that arises when using a linear-array transducer. Because such transducers generally have tall, narrow elements, they are essentially insensitive to out-of-plane acoustic waves, and the usually 3-D OAT problem reduces to a 2-D problem. Algorithms developed for the 3-D problem may not perform optimally in 2-D. We have implemented and evaluated a number of previously described OAT algorithms, including an exact (in 3-D) Fourier-based algorithm and a synthetic-aperture-based algorithm. We have also implemented a 2-D algorithm developed by Norton for reflection mode tomography that has not, to the best of our knowledge, been applied to OAT before. Our simulation studies of resolution, contrast, noise properties, and signal detectability measures suggest that Norton's approach-based algorithm has the best contrast, resolution, and signal detectability.

  3. Comparison tomography relocation hypocenter grid search and guided grid search method in Java island

    NASA Astrophysics Data System (ADS)

    Nurdian, S. W.; Adu, N.; Palupi, I. R.; Raharjo, W.

    2016-11-01

    The main data in this research is earthquake data recorded from 1952 to 2012 with 9162 P wave and 2426 events are recorded by 30 stations located around Java island. Relocation hypocenter processed using grid search and guidded grid search method. Then the result of relocation hypocenter become input for tomography pseudo bending inversion process. It can be used to identification the velocity distribution in subsurface. The result of relocation hypocenter by grid search and guided grid search method after tomography process shown in locally and globally. In locally area grid search method result is better than guided grid search according to geological reseach area. But in globally area the result of guided grid search method is better for a broad area because the velocity variation is more diverse than the other one and in accordance with local geological research conditions.

  4. Computerized Numerical Control Curriculum Guide.

    ERIC Educational Resources Information Center

    Reneau, Fred; And Others

    This guide is intended for use in a course in programming and operating a computerized numerical control system. Addressed in the course are various aspects of programming and planning, setting up, and operating machines with computerized numerical control, including selecting manual or computer-assigned programs and matching them with…

  5. Computerized Placement Tests: Background Readings.

    ERIC Educational Resources Information Center

    College Entrance Examination Board, Princeton, NJ.

    This document is a compilation of background readings for the user of Computerized Placement Tests (CPTs) developed by the College Board for student placement purposes. CPTs are computerized adaptive tests that test the individual abilities and backgrounds of examinees. CPTs are part of the ACCUPLACER student information management system. The…

  6. Reconstruction in interferometric synthetic aperture microscopy: comparison with optical coherence tomography and digital holographic microscopy.

    PubMed

    Sheppard, Colin J R; Kou, Shan Shan; Depeursinge, Christian

    2012-03-01

    It is shown that the spatial frequencies recorded in interferometric synthetic aperture microscopy do not correspond to exact backscattering [as they do in unistatic synthetic aperture radar (SAR)] and that the reconstruction process based on SAR is therefore based on an approximation. The spatial frequency response is developed based on the three-dimensional coherent transfer function approach and compared with that in optical coherence tomography and digital holographic microscopy.

  7. Dose reduction in abdominal computed tomography: intraindividual comparison of image quality of full-dose standard and half-dose iterative reconstructions with dual-source computed tomography.

    PubMed

    May, Matthias S; Wüst, Wolfgang; Brand, Michael; Stahl, Christian; Allmendinger, Thomas; Schmidt, Bernhard; Uder, Michael; Lell, Michael M

    2011-07-01

    We sought to evaluate the image quality of iterative reconstruction in image space (IRIS) in half-dose (HD) datasets compared with full-dose (FD) and HD filtered back projection (FBP) reconstruction in abdominal computed tomography (CT). To acquire data with FD and HD simultaneously, contrast-enhanced abdominal CT was performed with a dual-source CT system, both tubes operating at 120 kV, 100 ref.mAs, and pitch 0.8. Three different image datasets were reconstructed from the raw data: Standard FD images applying FBP which served as reference, HD images applying FBP and HD images applying IRIS. For the HD data sets, only data from 1 tube detector-system was used. Quantitative image quality analysis was performed by measuring image noise in tissue and air. Qualitative image quality was evaluated according to the European Guidelines on Quality criteria for CT. Additional assessment of artifacts, lesion conspicuity, and edge sharpness was performed. : Image noise in soft tissue was substantially decreased in HD-IRIS (-3.4 HU, -22%) and increased in HD-FBP (+6.2 HU, +39%) images when compared with the reference (mean noise, 15.9 HU). No significant differences between the FD-FBP and HD-IRIS images were found for the visually sharp anatomic reproduction, overall diagnostic acceptability (P = 0.923), lesion conspicuity (P = 0.592), and edge sharpness (P = 0.589), while HD-FBP was rated inferior. Streak artifacts and beam hardening was significantly more prominent in HD-FBP while HD-IRIS images exhibited a slightly different noise pattern. Direct intrapatient comparison of standard FD body protocols and HD-IRIS reconstruction suggest that the latest iterative reconstruction algorithms allow for approximately 50% dose reduction without deterioration of the high image quality necessary for confident diagnosis.

  8. Computerized audio processor

    NASA Astrophysics Data System (ADS)

    Weiss, M. R.; Aschkenasy, E.

    1983-05-01

    The Computerized Audio Processor (CAP) is a computer synthesized electronic filter that removes interference from received or recorded speech signals. The CAP automatically detects and attenuates impulse sounds and tones (e.g., ignition noise, switching transients, whistles, chirps, hum, buzzes, FSK telegraphy, etc). It also attenuates wideband random noise. All operations of the CAP are fully automatic. Input signals are processed in real time, with a maximum lag of 340 msec. The CAP implements three proven signal processing techniques. One of these (IMP) virtually eliminates most loud impulse noises. A second technique (DSS) automatically detects tones and attenuates them by up to 46 dB. The third technique (INTEL) provides up to 18 dB attenuation of wideband random noise.

  9. Computerized training management system

    DOEpatents

    Rice, Harold B.; McNair, Robert C.; White, Kenneth; Maugeri, Terry

    1998-08-04

    A Computerized Training Management System (CTMS) for providing a procedurally defined process that is employed to develop accreditable performance based training programs for job classifications that are sensitive to documented regulations and technical information. CTMS is a database that links information needed to maintain a five-phase approach to training-analysis, design, development, implementation, and evaluation independent of training program design. CTMS is designed using R-Base.RTM., an-SQL compliant software platform. Information is logically entered and linked in CTMS. Each task is linked directly to a performance objective, which, in turn, is linked directly to a learning objective; then, each enabling objective is linked to its respective test items. In addition, tasks, performance objectives, enabling objectives, and test items are linked to their associated reference documents. CTMS keeps all information up to date since it automatically sorts, files and links all data; CTMS includes key word and reference document searches.

  10. Computerized training management system

    DOEpatents

    Rice, H.B.; McNair, R.C.; White, K.; Maugeri, T.

    1998-08-04

    A Computerized Training Management System (CTMS) is disclosed for providing a procedurally defined process that is employed to develop accreditable performance based training programs for job classifications that are sensitive to documented regulations and technical information. CTMS is a database that links information needed to maintain a five-phase approach to training-analysis, design, development, implementation, and evaluation independent of training program design. CTMS is designed using R-Base{trademark}, an-SQL compliant software platform. Information is logically entered and linked in CTMS. Each task is linked directly to a performance objective, which, in turn, is linked directly to a learning objective; then, each enabling objective is linked to its respective test items. In addition, tasks, performance objectives, enabling objectives, and test items are linked to their associated reference documents. CTMS keeps all information up to date since it automatically sorts, files and links all data; CTMS includes key word and reference document searches. 18 figs.

  11. Computerizing natural history collections.

    PubMed

    Sunderland, Mary E

    2013-09-01

    Computers are ubiquitous in the life sciences and are associated with many of the practical and conceptual changes that characterize biology's twentieth-century transformation. Yet comparatively little has been written about how scientists use computers. Despite this relative lack of scholarly attention, the claim that computers revolutionized the life sciences by making the impossible possible is widespread, and relatively unchallenged. How did the introduction of computers into research programs shape scientific practice? The Museum of Vertebrate Zoology (MVZ) at the University of California, Berkeley provides a tractable way into this under-examined question because it is possible to follow the computerization of data in the context of long-term research programs.

  12. Comparison of different numerical treatments for x-ray phase tomography of soft tissue from differential phase projections

    SciTech Connect

    Pelliccia, Daniele; Vaz, Raquel; Svalbe, Imants; Morgan, Kaye S.; Marathe, Shashidhara; Xiao, Xianghui; Assoufid, Lahsen; Anderson, Rebecca A.; Topczewski, Jacek; Bryson-Richardson, Robert J.

    2015-04-21

    X-ray imaging of soft tissue is made difficult by their low absorbance. The use of x-ray phase imaging and tomography can significantly enhance the detection of these tissues and several approaches have been proposed to this end. Methods such as analyzer-based imaging or grating interferometry produce differential phase projections that can be used to reconstruct the 3D distribution of the sample refractive index. We report on the quantitative comparison of three different methods to obtain x-ray phase tomography with filtered back-projection from differential phase projections in the presence of noise. The three procedures represent different numerical approaches to solve the same mathematical problem, namely phase retrieval and filtered back-projection. It is found that obtaining individual phase projections and subsequently applying a conventional filtered back-projection algorithm produces the best results for noisy experimental data, when compared with other procedures based on the Hilbert transform. The algorithms are tested on simulated phantom data with added noise and the predictions are confirmed by experimental data acquired using a grating interferometer. The experiment is performed on unstained adult zebrafish, an important model organism for biomedical studies. The method optimization described here allows resolution of weak soft tissue features, such as muscle fibers.

  13. Comparison of different numerical treatments for x-ray phase tomography of soft tissue from differential phase projections

    NASA Astrophysics Data System (ADS)

    Pelliccia, Daniele; Vaz, Raquel; Svalbe, Imants; Morgan, Kaye S.; Marathe, Shashidhara; Xiao, Xianghui; Assoufid, Lahsen; Anderson, Rebecca A.; Topczewski, Jacek; Bryson-Richardson, Robert J.

    2015-04-01

    X-ray imaging of soft tissue is made difficult by their low absorbance. The use of x-ray phase imaging and tomography can significantly enhance the detection of these tissues and several approaches have been proposed to this end. Methods such as analyzer-based imaging or grating interferometry produce differential phase projections that can be used to reconstruct the 3D distribution of the sample refractive index. We report on the quantitative comparison of three different methods to obtain x-ray phase tomography with filtered back-projection from differential phase projections in the presence of noise. The three procedures represent different numerical approaches to solve the same mathematical problem, namely phase retrieval and filtered back-projection. It is found that obtaining individual phase projections and subsequently applying a conventional filtered back-projection algorithm produces the best results for noisy experimental data, when compared with other procedures based on the Hilbert transform. The algorithms are tested on simulated phantom data with added noise and the predictions are confirmed by experimental data acquired using a grating interferometer. The experiment is performed on unstained adult zebrafish, an important model organism for biomedical studies. The method optimization described here allows resolution of weak soft tissue features, such as muscle fibers.

  14. a-Stratified Computerized Adaptive Testing in the Presence of Calibration Error

    ERIC Educational Resources Information Center

    Cheng, Ying; Patton, Jeffrey M.; Shao, Can

    2015-01-01

    a-Stratified computerized adaptive testing with b-blocking (AST), as an alternative to the widely used maximum Fisher information (MFI) item selection method, can effectively balance item pool usage while providing accurate latent trait estimates in computerized adaptive testing (CAT). However, previous comparisons of these methods have treated…

  15. Neutron tomographic imaging of bone-implant interface: Comparison with X-ray tomography.

    PubMed

    Isaksson, Hanna; Le Cann, Sophie; Perdikouri, Christina; Turunen, Mikael J; Kaestner, Anders; Tägil, Magnus; Hall, Stephen A; Tudisco, Erika

    2017-10-01

    Metal implants, in e.g. joint replacements, are generally considered to be a success. As mechanical stability is important for the longevity of a prosthesis, the biological reaction of the bone to the mechanical loading conditions after implantation and during remodelling determines its fate. The bone reaction at the implant interface can be studied using high-resolution imaging. However, commonly used X-ray imaging suffers from image artefacts in the close proximity of metal implants, which limit the possibility to closely examine the bone at the bone-implant interface. An alternative ex vivo 3D imaging method is offered by neutron tomography. Neutrons interact with matter differently than X-rays; therefore, this study explores if neutron tomography may be used to enrich studies on bone-implant interfaces. A stainless steel screw was implanted in a rat tibia and left to integrate for 6weeks. After extracting the tibia, the bone-screw construct was imaged using X-ray and neutron tomography at different resolutions. Artefacts were visible in all X-ray images in the close proximity of the implant, which limited the ability to accurately quantify the bone around the implant. In contrast, neutron images were free of metal artefacts, enabling full analysis of the bone-implant interface. Trabecular structural bone parameters were quantified in the metaphyseal bone away from the implant using all imaging modalities. The structural bone parameters were similar for all images except for the lowest resolution neutron images. This study presents the first proof-of-concept that neutron tomographic imaging can be used for ex-vivo evaluation of bone microstructure and that it constitutes a viable, new tool to study the bone-implant interface tissue remodelling. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Comparison Between Perfusion Computed Tomography and Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Rectal Cancer

    SciTech Connect

    Kierkels, Roel G.J.; Backes, Walter H.; Janssen, Marco H.M.; Buijsen, Jeroen; Beets-Tan, Regina G.H.; Lambin, Philippe; Lammering, Guido; Oellers, Michel C.; Aerts, Hugo J.W.L.

    2010-06-01

    Purpose: To compare pretreatment scans with perfusion computed tomography (pCT) vs. dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in rectal tumors. Methods and Materials: Nineteen patients diagnosed with rectal cancer were included in this prospective study. All patients underwent both pCT and DCE-MRI. Imaging was performed on a dedicated 40-slice CT-positron emission tomography system and a 3-T MRI system. Dynamic contrast enhancement was measured in tumor tissue and the external iliac artery. Tumor perfusion was quantified in terms of pharmacokinetic parameters: transfer constant K{sup trans}, fractional extravascular-extracellular space v{sub e}, and fractional plasma volume v{sub p}. Pharmacokinetic parameter values and their heterogeneity (by 80% quantile value) were compared between pCT and DCE-MRI. Results: Tumor K{sup trans} values correlated significantly for the voxel-by-voxel-derived median (Kendall's tau correlation, tau = 0.81, p < 0.001) and 80% quantile (tau = 0.54, p = 0.04), as well as for the averaged uptake (tau = 0.58, p = 0.03). However, no significant correlations were found for v{sub e} and v{sub p} derived from the voxel-by-voxel-derived median and 80% quantile and derived from the averaged uptake curves. Conclusions: This study demonstrated for the first time that pCT provides K{sup trans} values comparable to those of DCE-MRI. However, no correlation was found for the v{sub e} and v{sub p} parameters between CT and MRI. Computed tomography can serve as an alternative modality to MRI for the in vivo evaluation of tumor angiogenesis in terms of the transfer constant K{sup trans}.

  17. Comparison between diffraction contrast tomography and high-energy diffraction microscopy on a slightly deformed aluminium alloy.

    PubMed

    Renversade, Loïc; Quey, Romain; Ludwig, Wolfgang; Menasche, David; Maddali, Siddharth; Suter, Robert M; Borbély, András

    2016-01-01

    The grain structure of an Al-0.3 wt%Mn alloy deformed to 1% strain was reconstructed using diffraction contrast tomography (DCT) and high-energy diffraction microscopy (HEDM). 14 equally spaced HEDM layers were acquired and their exact location within the DCT volume was determined using a generic algorithm minimizing a function of the local disorientations between the two data sets. The microstructures were then compared in terms of the mean crystal orientations and shapes of the grains. The comparison shows that DCT can detect subgrain boundaries with disorientations as low as 1° and that HEDM and DCT grain boundaries are on average 4 µm apart from each other. The results are important for studies targeting the determination of grain volume. For the case of a polycrystal with an average grain size of about 100 µm, a relative deviation of about ≤10% was found between the two techniques.

  18. Comparison between diffraction contrast tomography and high-energy diffraction microscopy on a slightly deformed aluminium alloy

    PubMed Central

    Renversade, Loïc; Quey, Romain; Ludwig, Wolfgang; Menasche, David; Maddali, Siddharth; Suter, Robert M.; Borbély, András

    2016-01-01

    The grain structure of an Al–0.3 wt%Mn alloy deformed to 1% strain was reconstructed using diffraction contrast tomography (DCT) and high-energy diffraction microscopy (HEDM). 14 equally spaced HEDM layers were acquired and their exact location within the DCT volume was determined using a generic algorithm minimizing a function of the local disorientations between the two data sets. The microstructures were then compared in terms of the mean crystal orientations and shapes of the grains. The comparison shows that DCT can detect subgrain boundaries with disorientations as low as 1° and that HEDM and DCT grain boundaries are on average 4 µm apart from each other. The results are important for studies targeting the determination of grain volume. For the case of a polycrystal with an average grain size of about 100 µm, a relative deviation of about ≤10% was found between the two techniques. PMID:26870379

  19. Comparison of ultrasound and computed tomography in the detection of pancreatic malignancy

    SciTech Connect

    Kamin, P.D.; Bernardino, M.E.; Wallace, S.; Jing, B.S.

    1980-12-01

    A retrospective analysis was performed on 102 patients who were examined by both ultrasound (US) and computed tomography (CT) for known or possible carcinoma of the pancreas. In 38% of the patients, ultrasonography was unsatisfactory due to overlying interfering intestinal gas or ascites, whereas only 2% of CT studies were unsatisfactory due to technical considerations. In comparing the two modalities, CT was found to be more accurate (96% CT vs. 84% US), and this became more significant when nondiagnostic studies were considered in evaluating accuracy (95% CT vs. 54% US). Because of the findings in this analysis, CT is recommended as the initial diagnostic imaging modality for the evaluation of possible pancreatic neoplasm.

  20. Thyroid imaging: comparison of high-resolution real-time ultrasound and computed tomography

    SciTech Connect

    Radecki, P.D.; Arger, P.H.; Arenson, R.L.; Jennings, A.S.; Coleman, B.G.; Mintz, M.C.; Kressel, H.Y.

    1984-10-01

    High-resolution real-time ultrasound (US) and computed tomography (CT) were compared in 48 patients with a clinical diagnosis of thyroid abnormality and also correlated with biopsy or surgery. The modalities were considered comparable in 38 cases (79%), while CT was superior in 5 and US in 5. Both techniques lacked histopathological specificity. CT appears to be advantageous in detecting substernal thyroid extension and confirming thyroiditis, while the ability of US to detect small nodules makes it the procedure of choice in evaluating suspected intrinsic thyroid abnormalities.

  1. Comparison of diffusion approximation and higher order diffusion equations for optical tomography of osteoarthritis

    NASA Astrophysics Data System (ADS)

    Yuan, Zhen; Zhang, Qizhi; Sobel, Eric; Jiang, Huabei

    2009-09-01

    In this study, a simplified spherical harmonics approximated higher order diffusion model is employed for 3-D diffuse optical tomography of osteoarthritis in the finger joints. We find that the use of a higher-order diffusion model in a stand-alone framework provides significant improvement in reconstruction accuracy over the diffusion approximation model. However, we also find that this is not the case in the image-guided setting when spatial prior knowledge from x-rays is incorporated. The results show that the reconstruction error between these two models is about 15 and 4%, respectively, for stand-alone and image-guided frameworks.

  2. Flat-detector computed tomography with intravenous contrast material application in experimental aneurysms: comparison with multislice CT and conventional angiography.

    PubMed

    Struffert, Tobias; Doelken, Marc; Adamek, Edyta; Schwarz, Marc; Engelhorn, Tobias; Kloska, Stephan; Ott, Sabine; Doerfler, Arnd

    2010-05-01

    Despite limited soft tissue resolution flat-detector computed tomography (FD-CT) provides substantial superior spatial resolution in comparison with multislice computed tomography (MS-CT). This may add value in the visualization of small vascular structures if intravenous contrast application leads to substantial opacification and visibility of intracranial vessels or aneurysms. To evaluate the feasibility of visualization of vascular structures by FD-CT angiography (FD-CTA) after intravenous contrast injection compared with MS-CTA and intra-arterial digital subtracted angiography (IADSA) in an animal model. Aneurysms were created in the right common carotid artery in six New Zealand White Rabbits using the elastase technique. Imaging was performed using FD-CTA, MS-CTA (injection of 1 ml/kg body weight) and IADSA. Anonymized volume rendering reconstruction (VRT), maximum intensity projection (MIP), and multiplanar reconstruction (MPR) images were reconstructed and evaluated by two experienced reviewers for aneurysm geometry and vascular structure anatomy using standard tools of a dedicated workstation. Aneurysms could be successfully created in all animals. Measurements of aneurysm geometry (aneurysm height, width, neck width) and vascular structures (brachiocephalic trunk, carotid artery diameter and plane) were nearly identical in all three modalities. Intra- and inter-observer correlations of the different parameters showed high r values between 0.83 and 0.99. Our results show the feasibility of FD-CTA in comparison with MS-CTA and IADSA in an animal model. Despite limited soft tissue resolution, opacification of vascular structures with sufficient contrast to the surrounding structures was possible in all animals. Vascular structures appeared better delineated in FD-CTA than in MS-CTA, probably due to the superior spatial resolution.

  3. Evaluation of ovarian structures using computerized microtomography.

    PubMed

    Paulini, Fernanda; Chaves, Sacha B; Rôlo, José Luiz J P; Azevedo, Ricardo B DE; Lucci, Carolina M

    2017-06-29

    Visualization and clear understanding of the ovarian structures are important in determining the stage of oestrus, helping to diagnose several pathologies and supporting advances in reproductive technologies. In this research, computerized microtomography (microCT) was used to explore and characterize the ovarian structure of seven mammalian species. Ovaries of rats, female dog, queens, cows, mares, sows and a female donkey were used. After microCT scanning, the same samples were prepared for histologic evaluation, used here as a validation criterion. It was possible to distinguish regions of the cortex and medulla, visualize the morphology and distribution of blood vessels, clearly observe corpus luteum and antral follicles, and visualize oocytes inside some antral follicles. This is the first report using microCT to explore and compare ovarian structures in several domestic mammals. MicroCT revealed great potential for the evaluation of ovarian structures. This research open prospects for the use of computerized tomography (CT) as a non-invasive approach to studying ovarian structures in live animals, which may be especially attractive for scientific study of development of ovarian structures and/or ovarian pathologies in small animals' models.

  4. Comparison of methods for the reduction of reconstructed layers in atmospheric tomography.

    PubMed

    Saxenhuber, Daniela; Auzinger, Günter; Louarn, Miska Le; Helin, Tapio

    2017-04-01

    For the new generation of extremely large telescopes (ELTs), the computational effort for adaptive optics (AO) systems is demanding even for fast reconstruction algorithms. In wide-field AO, atmospheric tomography, i.e., the reconstruction of turbulent atmospheric layers from wavefront sensor data in several directions of view, is the crucial step for an overall reconstruction. Along with the number of deformable mirrors, wavefront sensors and their resolution, as well as the guide star separation, the number of reconstruction layers contributes significantly to the numerical effort. To reduce the computational cost, a sparse reconstruction profile which still yields good reconstruction quality is needed. In this paper, we analyze existing methods and present new approaches to determine optimal layer heights and turbulence weights for the tomographic reconstruction. Two classes of methods are discussed. On the one hand, we have compression methods that downsample a given input profile to fewer layers. Among other methods, a new compression method based on discrete optimization of collecting atmospheric layers to subgroups and the compression by means of conserving turbulence moments is presented. On the other hand, we take a look at a joint optimization of tomographic reconstruction and reconstruction profile during atmospheric tomography, which is independent of any a priori information on the underlying input profile. We analyze and study the qualitative performance of these methods for different input profiles and varying fields of view in an ELT-sized multi-object AO setting on the European Southern Observatory end-to-end simulation tool OCTOPUS.

  5. A method of analysis of SPECT blood flow image data for comparison with computed tomography

    SciTech Connect

    Mountz, J.M.

    1989-03-01

    A consistent method for the qualitative analysis of regional cerebral blood flow on single-photon emission computed tomography (SPECT) imaging has not yet been realized. Regional analysis usually refers an area of abnormal tracer uptake to another region of brain (e.g., the contralateral hemisphere), but region of interest size and analysis differ between investigators. In patients who have had a stroke, the flow deficit size on the SPECT image often appears much larger than the abnormality visualized on computed tomography (CT), and confounds attempts to differentiate between ''purely'' infarcted brain tissue, ischemic brain tissue, edema, or brain tissue having diminution of flow resulting from deafferentation. The author presents a method to determine a flow deficit volume that can be easily calculated from the SPECT image, which yields a volume size that is equivalent to a hypothetical volume having zero blood flow. The method of calculation is objective, independent of region of interest size, and provides a SPECT volume deficit that may be correlated with the CT volume deficit, thus helping to differentiate ''purely'' infarcted tissue from tissue having infarction, edema, ischemia, and deafferentation.

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

    SciTech Connect

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

    2008-01-01

    value. {mu}CT and SR{mu}CT provided significantly different measurements of both BMC and TMD (p<0.05). In high volume fraction specimens, {mu}CT with 1200 mgHA/cm3 correction resulted in BMC and TMD values 16.7% and 15.0% lower, respectively, than SR{mu}CT values. In low volume fraction specimens, {mu}CT with 1200 mgHA/cm3 correction resulted in BMC and TMD values 12.8% and 12.9% lower, respectively, than SR{mu}CT values. {mu}CT and SR{mu}CT values were well-correlated when volume fraction groups were considered individually (BMC R2=0.97-1.00; TMD R2=0.78-0.99). Ash mass and density were higher than the SR{mu}CT equivalents by 8.6% in high volume fraction specimens and 10.9% in low volume fraction specimens (p<0.05). BMC values calculated by tomography were highly correlated with ash mass (ash versus {mu}CT R2=0.96-1.00; ash versus SR{mu}CT R2=0.99-1.00). TMD values calculated by tomography were moderately correlated with ash density (ash versus {mu}CT R2=0.64-0.72; ash versus SR{mu}CT R2=0.64). Spatially resolved comparisons highlighted substantial geometric nonuniformity in the {mu}CT data, which were reduced (but not eliminated) using the 1200 mg HA/cm3 beam hardening correction, and did not exist in the SR{mu}CT data. This study represents the first quantitative comparison of {mu}CT mineralization evaluation against SR{mu}CT and gravimetry. Our results indicate that {mu}CT mineralization measures are underestimated but well-correlated with SR{mu}CT and gravimetric data, particularly when volume fraction groups are considered individually.

  7. Physician Order Entry Or Nurse Order Entry? Comparison of Two Implementation Strategies for a Computerized Order Entry System Aimed at Reducing Dosing Medication Errors

    PubMed Central

    Fors, Uno GH; Tofighi, Shahram; Tessma, Mesfin; Ellenius, Johan

    2010-01-01

    Background Despite the significant effect of computerized physician order entry (CPOE) in reducing nonintercepted medication errors among neonatal inpatients, only a minority of hospitals have successfully implemented such systems. Physicians' resistance and users' frustration seem to be two of the most important barriers. One solution might be to involve nurses in the order entry process to reduce physicians’ data entry workload and resistance. However, the effect of this collaborative order entry method in reducing medication errors should be compared with a strictly physician order entry method. Objective To investigate whether a collaborative order entry method consisting of nurse order entry (NOE) followed by physician verification and countersignature is as effective as a strictly physician order entry (POE) method in reducing nonintercepted dose and frequency medication errors in the neonatal ward of an Iranian teaching hospital. Methods A four-month prospective study was designed with two equal periods. During the first period POE was used and during the second period NOE was used. In both methods, a warning appeared when the dose or frequency of the prescribed medication was incorrect that suggested the appropriate dosage to the physicians. Physicians’ responses to the warnings were recorded in a database and subsequently analyzed. Relevant paper-based and electronic medical records were reviewed to increase credibility. Results Medication prescribing for 158 neonates was studied. The rate of nonintercepted medication errors during the NOE period was 40% lower than during the POE period (rate ratio 0.60; 95% confidence interval [CI] .50, .71;P < .001). During the POE period, 80% of nonintercepted errors occurred at the prescription stage, while during the NOE period, 60% of nonintercepted errors occurred in that stage. Prescription errors decreased from 10.3% during the POE period to 4.6% during the NOE period (P < .001), and the number of warnings

  8. Physician order entry or nurse order entry? Comparison of two implementation strategies for a computerized order entry system aimed at reducing dosing medication errors.

    PubMed

    Kazemi, Alireza; Fors, Uno G H; Tofighi, Shahram; Tessma, Mesfin; Ellenius, Johan

    2010-02-26

    Despite the significant effect of computerized physician order entry (CPOE) in reducing nonintercepted medication errors among neonatal inpatients, only a minority of hospitals have successfully implemented such systems. Physicians' resistance and users' frustration seem to be two of the most important barriers. One solution might be to involve nurses in the order entry process to reduce physicians' data entry workload and resistance. However, the effect of this collaborative order entry method in reducing medication errors should be compared with a strictly physician order entry method. To investigate whether a collaborative order entry method consisting of nurse order entry (NOE) followed by physician verification and countersignature is as effective as a strictly physician order entry (POE) method in reducing nonintercepted dose and frequency medication errors in the neonatal ward of an Iranian teaching hospital. A four-month prospective study was designed with two equal periods. During the first period POE was used and during the second period NOE was used. In both methods, a warning appeared when the dose or frequency of the prescribed medication was incorrect that suggested the appropriate dosage to the physicians. Physicians' responses to the warnings were recorded in a database and subsequently analyzed. Relevant paper-based and electronic medical records were reviewed to increase credibility. Medication prescribing for 158 neonates was studied. The rate of nonintercepted medication errors during the NOE period was 40% lower than during the POE period (rate ratio 0.60; 95% confidence interval [CI] .50, .71;P < .001). During the POE period, 80% of nonintercepted errors occurred at the prescription stage, while during the NOE period, 60% of nonintercepted errors occurred in that stage. Prescription errors decreased from 10.3% during the POE period to 4.6% during the NOE period (P < .001), and the number of warnings with which physicians complied increased

  9. Comparison of single photon emission computed tomography-computed tomography, computed tomography, single photon emission computed tomography and planar scintigraphy for characterization of isolated skull lesions seen on bone scintigraphy in cancer patients

    PubMed Central

    Sharma, Punit; Jain, Tarun Kumar; Reddy, Rama Mohan; Faizi, Nauroze Ashgar; Bal, Chandrasekhar; Malhotra, Arun; Kumar, Rakesh

    2014-01-01

    Purpose: The purpose of this study is to evaluate the added value of single photon emission computed tomography-computed tomography (SPECT-CT) over planar scintigraphy, SPECT and CT alone for characterization of isolated skull lesions in bone scintigraphy (BS) in cancer patients. Materials and Methods: A total of 32 cancer patients (age: 39.5 ± 21.9; male: female - 1:1) with 36 isolated skull lesions on planar BS, underwent SPECT-CT of skull. Planar BS, SPECT, CT and SPECT-CT images were evaluated in separate sessions to minimize recall bias. A scoring scale of 1-5 was used, where 1 is definitely metastatic, 2 is probably metastatic, 3 is indeterminate, 4 is probably benign and 5 is definitely benign. With receiver operating characteristic analysis area under the curves (AUC) was calculated for each modality. For calculation of sensitivity, specificity and predictive values a Score ≤3 was taken as metastatic. Clinical/imaging follow-up and/or histopathology were taken as reference standard. Results: Of 36 skull lesions 11 lesions each were on frontal, parietal and occipital bone while three lesions were in the temporal bone. Of these 36 lesions, 16 were indeterminate (Score-3) on planar and SPECT, five on CT and none on SPECT-CT. The AUC was largest for SPECT-CT followed by CT, SPECT and planar scintigraphy, respectively. Planar scintigraphy was inferior to SPECT-CT (P = 0.006) and CT (P = 0.012) but not SPECT (P = 0.975). SPECT was also inferior to SPECT-CT (P = 0.007) and CT (P = 0.015). Although no significant difference was found between SPECT-CT and CT (P = 0.469), the former was more specific (100% vs. 94%). Conclusion: SPECT-CT is better than planar scintigraphy and SPECT alone for correctly characterizing isolated skull lesions on BS in cancer patients. It is more specific than CT, but provides no significant advantage over CT alone for this purpose. PMID:24591778

  10. Comparison of gastric vascular anatomy by monochromatic and polychromatic dual-energy spectral computed tomography imaging.

    PubMed

    Wan, Yamin; Li, Zhizhen; Ji, Nina; Gao, Jianbo

    2014-02-01

    To evaluate the use of monochromatic and polychromatic dual-energy spectral computed tomography (CT) imaging for preoperative assessment of gastric vascular anatomy. Patients with suspected gastric cancer underwent spectral CT to generate conventional 140  kVp polychromatic and monochromatic images with energy levels ranging from 40 to 140  keV during the late arterial and portal venous phases. Optimal monochromatic images were selected according to the contrast-to-noise ratio (CNR) for the gastric artery. Image quality was subjectively assessed. Display rates of the arteries were recorded. The study included 64 patients. Monochromatic images at 53 ± 3  keV provided the optimum CNR. At this energy level, subjective image scores were significantly higher for monochromatic images than polychromatic images. There were no significant differences in the display rates of arteries between polychromatic and optimal monochromatic images. Monochromatic images obtained with spectral CT can improve the visualization of gastric arteries.

  11. Renal trauma: radiological studies - comparison of urography, computed tomography, angiography, and radionuclide studies

    SciTech Connect

    Lang, E.K.; Sullivan, J.; Frentz, G.

    1985-01-01

    Excretory urography, computed radionuclide urography, angiography, and both conventional and dynamic computed tomography (CT) were compared with regard to accuracy, sensitivity, and specificity in 388 patients with renal trauma. Used as the triage examination, urography established the absence of significant renal injury with an accuracy of 87%, obviating further evaluation. Dynamic CT proved to be the best methods of assessing parenchymal injuries, establishing the correct diagnosis in 129 out of 130 cases compared to 116/130 for conventional CT. Angiography was the procedure of choice for diagnosis and categorization of renal artery injuries, which were diagnosed correctly in all 43 cases. The choice between dynamic CT and angiography as the second examination rests upon careful evaluation of clinical and urographic findings for signs of renal artery injury which would mandate angiographic assessment.

  12. Tomographic imaging of incipient dental-caries using optical coherence tomography and comparison with various modalities

    NASA Astrophysics Data System (ADS)

    Na, Jihoon; Baek, Jae Ho; Ryu, Seon Young; Lee, Changsu; Lee, Byeong Ha

    2009-07-01

    We present the optical coherence tomography (OCT) made to investigate the early dental caries in human teeth and compare its results with those taken by conventional imaging modalities including light illuminating examination (LIE), digital intra-oral radiography (DIOR), and electron probe micro analyzer (EPMA). Morphological features and caries-involved areas of the dental structure were mainly investigated by LIE, DIOR, and OCT to study the infection of the caries lesion in pits and fissures. The biochemical information acquired with EPMA and the morphological features taken with OCT in the early stage of caries were compared and analyzed to present an objective and practical index for the degree of caries. The experimental results allow us to conclude that OCT could be used to provide quantitative analysis of caries based on the reflectivity difference in the specimen.

  13. Magnetic resonance imaging of the adrenal glands: a comparison with computed tomography

    SciTech Connect

    Schultz, C.L.; Haaga, J.R.; Fletcher, B.D.; Alfidi, R.J.; Schultz, M.A.

    1984-12-01

    This investigation compared magnetic resonance imaging (MRI) with computed tomography (CT) in the evaluation of normal and abnormal adrenal glands. Thirty normal volunteers were studied with MRI, and the results were compared with a retrospective review of 30 normal CT examinations. CT identified both adrenal glands in all 30 patients. MRI identified both glands in 29 of 30 volunteers. There were no statistically significant differences between the two imaging techniques using chi-square analysis. Twenty-one patients with abnormal adrenal gland(s) detected with CT were also studied with MRI. The abnormalities studied included bilateral hyperplasia (three patients), adenoma (two), myelolipoma (one), adrenal metastases (six), adrenal hemorrhage (two), and neuroblastoma (seven). MRI detected the abnormal adrenal gland(s) in 20 of 21 patients. The CT and MRI features of the adrenal lesions are discussed.

  14. Computerized molecular modeling of carbohydrates

    USDA-ARS?s Scientific Manuscript database

    Computerized molecular modleing continues to increase in capability and applicability to carbohydrates. This chapter covers nomenclature and conformational aspects of carbohydrates, perhaps of greater use to carbohydrate-inexperienced computational chemists. Its comments on various methods and studi...

  15. Comparison of computed tomography features between follicular neoplasm and nodular hyperplasia.

    PubMed

    Lee, Kwang Hwi; Kim, Dong Wook; Baek, Jin Wook; Lee, Yoo Jin; Choo, Hye Jung; Cho, Young Jun; Lee, Sun Joo; Park, Young Mi; Jung, Soo Jin; Baek, Hye Jin

    2016-10-03

    To date, appropriate management for Bethesda IV thyroid nodules is controversial, and no specific features of follicular neoplasm and nodular hyperplasia on ultrasonography, computed tomography (CT), or other imaging modalities have been reported. This study aimed to compare CT features of follicular neoplasm and nodular hyperplasia and to determine the specific CT features that could be used to distinguish follicular neoplasm from nodular hyperplasia. In 122 patients who underwent preoperative CT of the neck and thyroid surgery, 59 follicular neoplasms and 65 nodular hyperplasias were included. In each case, non-enhanced and contrast-enhanced CT images were obtained, and a single radiologist retrospectively analyzed CT images, including degree and pattern of attenuation, nodular configuration, margin, shape, pattern of calcification, degree and pattern of nodular enhancement, and CT halo sign. A univariate and multivariate logistic regression analyses were used to evaluate the predictive power of each variable and CT features with a high predictive power, respectively. According to the univariate analysis, iso-attenuation, intraglandular configuration, smooth margin, ovoid shape, decreased enhancement, and absence of CT halo sign were more frequently observed in nodular hyperplasia (p < 0.05), whereas low attenuation, expansile configuration, lobulated margin, taller-than-wide shape, increased enhancement, and presence of computed tomography halo sign were more frequently observed in follicular neoplasm (p < 0.05). Multivariate analysis revealed significant differences in configuration (OR: 2.73, 1.13-6.57), degree of enhancement (OR: 2.14, 1.21-3.78), and presence of CT halo sign (OR: 7.97, 2.74-23.37) between follicular neoplasm and nodular hyperplasia (p < 0.05). Neck CT may be helpful for distinguishing follicular neoplasm from nodular hyperplasia. Rretrospectively registered.

  16. Three-dimensional transient hydraulic tomography and comparison to other heterogeneity imaging methods

    NASA Astrophysics Data System (ADS)

    Berg, S. J.; Illman, W. A.

    2010-12-01

    Delineating the subsurface distribution of hydraulic conductivity (K) and specific storage (Ss) is of great importance in many areas of hydrogeology, especially for water supply and contaminant transport investigations. However, acquiring reliable distributions of such hydraulic parameters is often difficult and expensive. Hydraulic tomography has recently been proposed as an alternative to various heterogeneity delineation methods for imaging subsurface K and Ss distributions. The technique has been tested by various researchers throughout the world using synthetic simulations and laboratory experiments. It has also been evaluated in the field at a number of sites in different geologic settings. Recently, we conducted a detailed hydraulic tomography survey at the North Campus Research Site (NCRS) situated at the University of Waterloo in a highly heterogeneous glaciofluvial aquifer-aquitard sequence. A plot measuring 15 m by 15 m and approximately 18 m deep was instrumented with four, 7-channel Continuous Multichannel Tubing (CMT) wells consisting of a total of 28 observation ports. Each observation port was instrumented with a pressure transducer to record the response of the system to pumping. Additionally, 4 multi-screen/nested wells are placed at the corners of the plot and 1 multi-screen well is placed in the center of the plot. Using a straddle-packer system, 10 locations have been pumped to date, yielding a detailed record of drawdown curves which are currently being analyzed with the SSLE code developed by Zhu and Yeh (2005). The analysis consists of utilizing approximately half of the drawdown records while the others are reserved for validation purposes. We are also comparing the results of these inversions to various heterogeneity interpolation methods such as kriging and T-PROGS.

  17. Computerized international geothermal information systems

    SciTech Connect

    Phillips, S.L.; Lawrence, J.D.; Lepman, S.R.

    1980-03-01

    The computerized international geothermal energy information system is reviewed. The review covers establishment of the Italy - United States linked data centers by the NATO Committee on Challenges of Modern Society, through a bilateral agreement, and up to the present time. The result of the information exchange project is given as the bibliographic and numerical data available from the data centers. Recommendations for the exchange of computerized geothermal information at the international level are discussed.

  18. Experience with the use of the COM computerized conferencing system

    NASA Astrophysics Data System (ADS)

    Palme, J.

    1981-12-01

    Studies of the effect of the system are summarized. Similar computerized conferencing systems were also investigated. Information about how much KOM (the Swedish language version of COM) is used, what it is used for, which people use it, the user opinions about the advantages and disadvantages of the system, and a comparison of its cost with other communication media is presented.

  19. The Role of Schemes in Designing Computerized Environments.

    ERIC Educational Resources Information Center

    Hershkovitz, Sara; Nesher, Pearla

    1996-01-01

    Comparison of the effectiveness of two computerized environments, Schemes for Problem Analysis (SPA) and Algebraic Proposer (AP), with two sixth-grade classes found that in solving easy word problems, both software systems were equally helpful, but in harder word problems, those students who learned with SPA experienced more success than those who…

  20. Beam hardening artifacts by dental implants: Comparison of cone-beam and 64-slice computed tomography scanners

    PubMed Central

    Esmaeili, Farzad; Johari, Masume; Haddadi, Pezhman

    2013-01-01

    Background: Cone beam computed tomography (CBCT) is an alternative to a computed tomography (CT) scan, which is appropriate for a wide range of craniomaxillofacial indications. The long-term use of metallic materials in dentistry means that artifacts caused by metallic restorations in the oral cavity should be taken into account when utilizing CBCT and CT scanners. The aim of this study was to quantitatively compare the beam hardening artifacts produced by dental implants between CBCT and a 64-Slice CT scanner. Materials and Methods: In this descriptive study, an implant drilling model similar to the human mandible was used in the present study. The implants (Dentis) were placed in the canine, premolar and molar areas. Three series of scans were provided from the implant areas using Somatom Sensation 64-slice and NewTom VGi (CBCT) CT scanners. Identical images were evaluated by three radiologists. The artifacts in each image were determined based on pre-determined criteria. Kruskal-Wallis test was used to compare mean values; Mann-Whitney U test was used for two-by-two comparisons when there was a statistical significance (P < 0.05). Results: The images of the two scanners had similar resolutions in axial sections (P = 0.299). In coronal sections, there were significant differences in the resolutions of the images produced by the two scanners (P < 0.001), with a higher resolution in the images produced by NewTom VGi scanner. On the whole, there were significant differences between the resolutions of the images produced by the two CT scanners (P < 0.001), with higher resolution in the images produced by NewTom VGi scanner in comparison to those of Somatom Sensation. Conclusion: Given the high quality of the images produced by NewTom VGi and the lower costs in comparison to CT, the use of the images of this scanner in dental procedures is recommended, especially in patients with extensive restorations, multiple prostheses and previous implants. PMID:24019808

  1. Computerized voiding diary.

    PubMed

    Rabin, J M; McNett, J; Badlani, G H

    1993-01-01

    An electronic, computerized voiding diary, "Compu-Void" (patent pending) was developed in order to simplify, augment, and automate patients' recording of bladder symptomatology. A voiding diary as a tool has the potential to provide essential information for a more complete diagnostic and therefore therapeutic picture for each patient. Two major problems with the standard written voiding diary have been a lack of patient compliance and the limited amount of information it garners. Twenty-five women with various types of voiding dysfunctions were compared to twenty-five age and parity-matched control women in order to determine patient preferences of the Compu-Void when compared to the standard written voiding diary, compliance with each method, and amount and quality of information obtained with each method. Over 90% of subjects and over 70% of control group patients preferred the Compu-Void over the written diary (P < 0.005). The amount and quality of information obtained with Compu-Void exceeded that obtained with the written method.

  2. Comparison of orthopantomography and computed tomography image for assessing the relationship between impacted mandibular third molar and mandibular canal.

    PubMed

    Katakam, Shravan Kumar; Shankar, Uma; Thakur, Deepak; Reddy, T Praveen Kumar; Hari, K R; Janga, Deepti

    2012-11-01

    Permanent mandibular third molar are most commonly impacted teeth. In planning the surgical removal of mandibular third molar, correct diagnosis requires not only their precise spatial location, but also a thorough and accurate assessment of the intimate relationship with adjacent anatomical structures. Various imaging modalities have been used for localizing the mandibular third molar but not satisfactorily. This prospective study of 30 patients with 42 impacted mandibular third molars was carried out with the aim of finding evidence for justifying the use of computed tomography and orthopantomography as a diagnostic modality, prior to surgical intervention of impacted mandibular third molar. Subjective evaluation of the CT and OPG images by two observed had shown that there was significant difference between the CT and OPG for radiographic visibility of mandibular canal in relation to third molar. Data analysis was done with Chi-square test (X(2)) and z-test to find the significant difference between the two radiographic modalities OPG and CT in localizing special relationship of impacted mandibular third molar. The comparison of OPG and CT showed z-value >1.5 in darkening of roots (1.98), deflection of root (2.00) interruption of z-value = 0 in narrowing of canal and dark, bifid apexes. Also it showed p-value <0.05 in all the radiographic signs except narrowing of mandibular canal and and dark and bifid apexes. The spiral CT image provides a unique opportunity to determine the exact position of impacted mandibular third molar and their relationship to adjacent structure in all three planes. Computed tomography is highly instrumental in depicting the relationship of mandibular third molar with inferior alveolar nerve canal before treatment and accurate appraisal of the several aspects can be made regarding prognosis.

  3. Comparison of rubidium-82 positron emission tomography and thallium-201 SPECT imaging for detection of coronary artery disease

    SciTech Connect

    Stewart, R.E.; Schwaiger, M.; Molina, E.; Popma, J.; Gacioch, G.M.; Kalus, M.; Squicciarini, S.; al-Aouar, Z.R.; Schork, A.; Kuhl, D.E. )

    1991-06-15

    The diagnostic performance of rubidium-82 (Rb-82) positron emission tomography (PET) and thallium-201 (Tl-201) single-photon emission-computed tomography (SPECT) for detecting coronary artery disease was investigated in 81 patients (52 men, 29 women). PET studies using 60 mCi of Rb-82 were performed at baseline and after intravenous infusion of 0.56 mg/kg dipyridamole in conjunction with handgrip stress. Tl-201 SPECT was performed after dipyridamole-handgrip stress and, in a subset of patients, after treadmill exercise. Sensitivity, specificity and overall diagnostic accuracy were assessed using both visually and quantitatively interpreted coronary angiograms. The overall sensitivity, specificity and accuracy of PET for detection of coronary artery disease (greater than 50% diameter stenosis) were 84, 88 and 85%, respectively. In comparison, the performance of SPECT revealed a sensitivity of 84%, specificity of 53% (p less than 0.05 vs PET) and accuracy of 79%. Similar results were obtained using either visual or quantitative angiographic criteria for severity of coronary artery disease. In 43 patients without prior myocardial infarction, the sensitivity for detection of disease was 71 and 73%, respectively, similar for both PET and SPECT. There was no significant difference in diagnostic performance between imaging modalities when 2 different modes of stress (exercise treadmill vs intravenous dipyridamole plus handgrip) were used with SPECT imaging. Thus, Rb-82 PET provides improved specificity compared with Tl-201 SPECT for identifying coronary artery disease, most likely due to the higher photon energy of Rb-82 and attenuation correction provided by PET. However, post-test referral cannot be entirely excluded as a potential explanation for the lower specificity of Tl-201 SPECT.

  4. Comparison of Ultrahigh- and Standard-Resolution Optical Coherence Tomography for Imaging Macular Hole Pathology and Repair

    PubMed Central

    Ko, Tony H.; Fujimoto, James G.; Duker, Jay S.; Paunescu, Lelia A.; Drexler, Wolfgang; Baumal, Caroline R.; Puliafito, Carmen A.; Reichel, Elias; Rogers, Adam H.; Schuman, Joel S.

    2007-01-01

    of the macular hole architectural morphology. The increased resolution of UHR-OCT enables the visualization of photoreceptor morphology associated with macular holes. This promises to lead to a better understanding of the pathogenesis of macular holes, the causes of visual loss secondary to macular holes, the timing of surgical repair, and the evaluation of postsurgical outcome. Ultrahigh-resolution optical coherence tomography imaging of macular holes that correspond to known alterations in retinal morphology can be used to interpret retinal morphology in UHR-OCT images. Comparisons of UHR-OCT images with standard-resolution OCT images can establish a baseline for the better interpretation of clinical standard-resolution OCT images. The ability to visualize photoreceptors and their integrity or impairment is an indicator of macular hole progression and surgical outcome. PMID:15522369

  5. Comparison of magmatic structures beneath Redoubt (Alaska) and Toba (Northern Sumatra) volcanoes derived from local earthquake tomography studies

    NASA Astrophysics Data System (ADS)

    Kasatkina, Ekaterina; Koulakov, Ivan; West, Michael

    2014-05-01

    We present the results of seismic tomography studies of two different volcanoes - Mt. Redoubt and Toba caldera. These two subduction related volcanoes have different ages and scales of eruption activity. Velocity model beneath the Redoubt volcano is based on tomographic inversion of P- and S- arrival time data from over 4000 local earthquakes recorded by 19 stations since 1989 to 2012 provided by the Alaskan Volcano Observatory (University of Fairbanks). Just below the volcano edifice we observe an anomaly of high Vp/Vs ratio reaching 2.2 which is seen down to 2- 3 km depth. This indicates a presence of partially molten substance or fluid filled rocks. We can suggest that anomaly area matches with volcano magma chamber. One of the previous velocity models of Toba caldera was obtained by Koulakov et al. (2009) and was based on data recorded by temporary network from January to May 1995. In this study this "old" dataset was supplemented with "new" data recorded by a temporary network deployed in approximately same area by GFZ-Potsdam from May to November 2008. We have manually picked the arrival times from the local events recorded by the later experiment and then performed the tomography inversion for the combined dataset using the LOTOS code (Koulakov, 2009). In the uppermost layers we observe strong low-velocity P- and S- anomalies within the Caldera which can be interpreted by the presence of think sediments filling the caldera. In the lower crust and uppermost mantle we observe a vertical anomaly of low P- and S-velocities which probably represent the path of conduits which link the caldera area with the slab. Similar to Redoubt volcano, resulting velocity model of Toba has an increased value of Vp/Vs ratio that indicates a presence of magma reservoir. Comparison of the tomographic results obtained for the completely different volcanic systems helps in understanding some basic principles of feeding the volcanoes. This study was partly supported by the Project #7

  6. Comparison of breast density measurements made using ultrasound tomography and mammography

    NASA Astrophysics Data System (ADS)

    Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Krycia, Mark; Sherman, Mark E.; Boyd, Norman; Gierach, Gretchen L.

    2015-03-01

    Women with elevated mammographic percent density, defined as the ratio of fibroglandular tissue area to total breast area on a mammogram are at an increased risk of developing breast cancer. Ultrasound tomography (UST) is an imaging modality that can create tomographic sound speed images of a patient's breast, which can then be used to measure breast density. These sound speed images are useful because physical tissue density is directly proportional to sound speed. The work presented here updates previous results that compared mammographic breast density measurements with UST breast density measurements within an ongoing study. The current analysis has been expanded to include 158 women with negative digital mammographic screens who then underwent a breast UST scan. Breast density was measured for both imaging modalities and preliminary analysis demonstrated strong and positive correlations (Spearman correlation coefficient rs = 0.703). Additional mammographic and UST related imaging characteristics were also analyzed and used to compare the behavior of both imaging modalities. Results suggest that UST can be used among women with negative mammographic screens as a quantitative marker of breast density that may avert shortcomings of mammography.

  7. Accuracy of Intraoperative Computed Tomography during Deep Brain Stimulation Procedures: Comparison with Postoperative Magnetic Resonance Imaging.

    PubMed

    Bot, Maarten; van den Munckhof, Pepijn; Bakay, Roy; Stebbins, Glenn; Verhagen Metman, Leo

    2017-01-01

    To determine the accuracy of intraoperative computed tomography (iCT) in localizing deep brain stimulation (DBS) electrodes by comparing this modality with postoperative magnetic resonance imaging (MRI). Optimal lead placement is a critical factor for the outcome of DBS procedures and preferably confirmed during surgery. iCT offers 3-dimensional verification of both microelectrode and lead location during DBS surgery. However, accurate electrode representation on iCT has not been extensively studied. DBS surgery was performed using the Leksell stereotactic G frame. Stereotactic coordinates of 52 DBS leads were determined on both iCT and postoperative MRI and compared with intended final target coordinates. The resulting absolute differences in X (medial-lateral), Y (anterior-posterior), and Z (dorsal-ventral) coordinates (ΔX, ΔY, and ΔZ) for both modalities were then used to calculate the euclidean distance. Euclidean distances were 2.7 ± 1.1 and 2.5 ± 1.2 mm for MRI and iCT, respectively (p = 0.2). Postoperative MRI and iCT show equivalent DBS lead representation. Intraoperative localization of both microelectrode and DBS lead in stereotactic space enables direct adjustments. Verification of lead placement with postoperative MRI, considered to be the gold standard, is unnecessary. © 2017 The Author(s) Published by S. Karger AG, Basel.

  8. Comparison of Ga-67 planar imaging and single photon emission computed tomography in malignant chest disease

    SciTech Connect

    Tumeh, S.S.; Rosenthal, D.; Kaplan, W.D.; English, R.E.; Holman, B.L.

    1985-05-01

    To determine the value of Ga-67 single photon emission computed tomography (SPECT) in patients (pts) with malignant chest disease, the authors compared Ga-67 planar scans (ps) and SPECT with the medical records in twenty-five consecutive patients. Twenty-three examinations were performed on 17 pts with Hodgkin's disease (HD) and three pts with non-Hodgkin's lymphoma. Five examinations were performed on 5 pts with bronchogenic carcinoma (BC). The two modalities were evaluated for (1) presence or absence of disease, (2) number of foci of abnormal uptake and (3) extent of disease. In pts with lymphoma, SPECT defined the extent of disease better than planar imaging in eight examinations; it demonstrated para-cardial involvement in one pt, separated hilar from mediastinal disease in 4, and demonstrated posterior mediastinal disease in 3. SPECT clarified suspicious foci on planar images in seven examinations, correctly ruled out disease in two pts with equivocal planar images and did not exchange planar image findings in six examinations. In pts with bronchogenic carcinoma, both medalities correctly ruled out mediastinal involvement in three pts. SPECT detected mediastinal lymph node involvement in one pt with equivocal planar images. Both SPECT and planar imaging missed direct tumor extension to the mediastinum in one pt. They conclude that Ga-67 with SPECT is better than planar images for staging of chest lymphoma and BC. Since it defines different lymph node groups it carries a good potential for staging as well as follow up of those pts.

  9. Comparison of rotational imaging optical coherence tomography and selective plane illumination microscopy for embryonic study

    NASA Astrophysics Data System (ADS)

    Wu, Chen; Ran, Shihao; Le, Henry H.; Singh, Manmohan; Larina, Irina V.; Mayerich, David; Dickinson, Mary E.; Larin, Kirill V.

    2016-03-01

    The mouse is a common model for studying developmental diseases. Different optical techniques have been developed to investigate mouse embryos, but each has its own set of limitations and restrictions. In this study, we imaged the same E9.5 mouse embryo with rotational imaging Optical Coherence Tomography (RI-OCT) and Selective Plane Illumination Microscopy (SPIM), and compared the two techniques. Results demonstrate that both methods can provide images with micrometer-scale spatial resolution. The RI-OCT technique was developed to increase imaging depth of OCT by performing traditional OCT imaging at multiple sides and co-registering the images. In SPIM, optical sectioning is achieved by illuminating the sample with a sheet of light. In this study, the images acquired from both techniques are compared with each other to evaluate the benefits and drawbacks of each technique for embryonic imaging. Since 3D stacks can be obtained by SPIM from different angles by rotating the sample, it might be possible to build a hybrid setup of two imaging modalities to combine the advantages of each technique.

  10. Use of optical coherence tomography in delineating airways microstructure: comparison of OCT images to histopathological sections

    NASA Astrophysics Data System (ADS)

    Yang, Ying; Whiteman, Suzanne; Gey van Pittius, Daniel; He, Yonghong; Wang, Ruikang K.; Spiteri, Monica A.

    2004-04-01

    An ideal diagnostic system for the human airways should be able to detect and define early development of premalignant pathological lesions, to facilitate optimal curative treatment and prevent irreversible and/or invasive lung disease. There is great need for exploration of safe, repeatable imaging techniques which can run at real-time and with high spatial resolution. In this study, optical coherence tomography (OCT) was utilized to acquire cross-sectional images of upper and lower airways using fresh pig lung resections as a model system. Obtained OCT images were compared with parallel tissue characterization by conventional histological analysis. Our objective was to determine whether OCT differentiates the composite structural layers and inherent anatomical variations along different airway locations. The data show that OCT can clearly display the multilayered structure of the airways. The subtle architectural differences in three separate anatomical locations including trachea, main bronchus and tertiary bronchus were clearly delineated. Images of the appropriate anatomical profiles, with depth of up to 2 mm and 10 µm spatial resolution were obtained by our current OCT system, which was sufficient for recognition of the epithelium, subepithelial tissues and cartilage. In addition, the relative thickness of individual structural components was accurately reflected and comparable to histological sections. These data support OCT as a highly feasible, optical biopsy tool, which merits further exploration for early diagnosis of human airway epithelial pathology.

  11. Diabetic Macular Ischemia Diagnosis: Comparison between Optical Coherence Tomography Angiography and Fluorescein Angiography

    PubMed Central

    Lima, Talita Toledo; Louzada, Ricardo Noguera; Rassi, Alessandra Thome; Isaac, David Leonardo Cruvinel; Avila, Marcos

    2016-01-01

    Purpose. To compare fluorescein angiography (FA) and optical coherence tomography angiography (OCTA) images of foveal avascular zone (FAZ) in patients with diabetic retinopathy (DR) with and without diabetic macular ischemia (DMI). Methods. The Wilcoxon signed-rank test was used to compare area measurements and p values of <0.05 were considered statistically significant. FA and OCTA images were independently graded by 2 observers that reached agreement regarding quantitative DMI according established protocols. The ischemic area was divided into “large” macular ischemia (superior to 0.32 mm2) and “small” (inferior to 0.32 mm2) groups. Quantitative analyses of the FAZ were performed using custom software. Results. Thirty-four eyes from 34 diabetic patients were enrolled. Subjects with DMI presented a mean area on FA and OCTA of 0.68 ± 0.53 mm2 and 0.58 ± 0.35 mm2, respectively (p = 0.1374). Patients without DMI presented a mean area on FA and OCTA of 0.19 ± 0.67 mm2 and 0.20 ± 0.79 mm2, respectively (p = 0.9594). The ICC for the FAZ measurements between the 2 observers on FA and OCTA was 0.96 and 0.92, respectively. Conclusion. OCTA represents a novel technique for the diagnosis of DMI and it may become an alternative to FA for this purpose. PMID:27891250

  12. Comparison of Kasai Autocorrelation and Maximum Likelihood Estimators for Doppler Optical Coherence Tomography

    PubMed Central

    Chan, Aaron C.; Srinivasan, Vivek J.

    2013-01-01

    In optical coherence tomography (OCT) and ultrasound, unbiased Doppler frequency estimators with low variance are desirable for blood velocity estimation. Hardware improvements in OCT mean that ever higher acquisition rates are possible, which should also, in principle, improve estimation performance. Paradoxically, however, the widely used Kasai autocorrelation estimator’s performance worsens with increasing acquisition rate. We propose that parametric estimators based on accurate models of noise statistics can offer better performance. We derive a maximum likelihood estimator (MLE) based on a simple additive white Gaussian noise model, and show that it can outperform the Kasai autocorrelation estimator. In addition, we also derive the Cramer Rao lower bound (CRLB), and show that the variance of the MLE approaches the CRLB for moderate data lengths and noise levels. We note that the MLE performance improves with longer acquisition time, and remains constant or improves with higher acquisition rates. These qualities may make it a preferred technique as OCT imaging speed continues to improve. Finally, our work motivates the development of more general parametric estimators based on statistical models of decorrelation noise. PMID:23446044

  13. Comparison of different metrics for analysis and visualization in spectroscopic optical coherence tomography

    PubMed Central

    Jaedicke, Volker; Agcaer, Semih; Robles, Francisco E.; Steinert, Marian; Jones, David; Goebel, Sebastian; Gerhardt, Nils C.; Welp, Hubert; Hofmann, Martin R.

    2013-01-01

    Spectroscopic Optical Coherence Tomography (S-OCT) extracts depth resolved spectra that are inherently available from OCT signals. The back scattered spectra contain useful functional information regarding the sample, since the light is altered by wavelength dependent absorption and scattering caused by chromophores and structures of the sample. Two aspects dominate the performance of S-OCT: (1) the spectral analysis processing method used to obtain the spatially-resolved spectroscopic information and (2) the metrics used to visualize and interpret relevant sample features. In this work, we focus on the second aspect, where we will compare established and novel metrics for S-OCT. These concepts include the adaptation of methods known from multispectral imaging and modern signal processing approaches such as pattern recognition. To compare the performance of the metrics in a quantitative manner, we use phantoms with microsphere scatterers of different sizes that are below the system’s resolution and therefore cannot be differentiated using intensity based OCT images. We show that the analysis of the spectral features can clearly separate areas with different scattering properties in multi-layer phantoms. Finally, we demonstrate the performance of our approach for contrast enhancement in bovine articular cartilage. PMID:24409393

  14. Comparison of two regularization methods for soft x-ray tomography at Tore Supra

    NASA Astrophysics Data System (ADS)

    Jardin, A.; Mazon, D.; Bielecki, J.

    2016-04-01

    Soft x-ray (SXR) emission in the range 0.1-20 keV is widely used to obtain valuable information on tokamak plasma physics, such as particle transport, magnetic configuration or magnetohydrodynamic activity. In particular, 2D tomography is the usual plasma diagnostic to access the local SXR emissivity. The tomographic inversion is traditionally performed from line-integrated measurements of two or more cameras viewing the plasma in a poloidal cross-section, like at Tore Supra (TS). Unfortunately, due to the limited number of measured projections and presence of noise, the tomographic reconstruction of SXR emissivity is a mathematical ill-posed problem. Thus, obtaining reliable results of the tomographic inversion is a very challenging task. In order to perform the reconstruction, inversion algorithms implemented in present tokamaks use a priori information as additional constraints imposed on the plasma SXR emissivity. Among several potential inversion methods, some of them have been identified as well suited to tokamak plasmas. The purpose of this work is to compare two promising inversion methods, i.e. the minimum fisher information method already used at TS and planned for WEST configuration, and the alternative 2nd order Phillips-Tikhonov regularization with smoothness constraints imposed on the second derivative norm. Respective accuracy of both reconstruction methods as well as overall robustness and computational time are studied, using several synthetic SXR emissivity profiles. Finally, a real case is studied through tomographic reconstruction from TS SXR database.

  15. Methods and algorithms for optical coherence tomography-based angiography: a review and comparison

    NASA Astrophysics Data System (ADS)

    Zhang, Anqi; Zhang, Qinqin; Chen, Chieh-Li; Wang, Ruikang K.

    2015-10-01

    Optical coherence tomography (OCT)-based angiography is increasingly becoming a clinically useful and important imaging technique due to its ability to provide volumetric microvascular networks innervating tissue beds in vivo without a need for exogenous contrast agent. Numerous OCT angiography algorithms have recently been proposed for the purpose of contrasting microvascular networks. A general literature review is provided on the recent progress of OCT angiography methods and algorithms. The basic physics and mathematics behind each method together with its contrast mechanism are described. Potential directions for future technical development of OCT based angiography is then briefly discussed. Finally, by the use of clinical data captured from normal and pathological subjects, the imaging performance of vascular networks delivered by the most recently reported algorithms is evaluated and compared, including optical microangiography, speckle variance, phase variance, split-spectrum amplitude decorrelation angiography, and correlation mapping. It is found that the method that utilizes complex OCT signal to contrast retinal blood flow delivers the best performance among all the algorithms in terms of image contrast and vessel connectivity. The purpose of this review is to help readers understand and select appropriate OCT angiography algorithm for use in specific applications.

  16. Cerebral blood volume imaging by flat detector computed tomography in comparison to conventional multislice perfusion CT.

    PubMed

    Struffert, Tobias; Deuerling-Zheng, Yu; Kloska, Stephan; Engelhorn, Tobias; Boese, Jan; Zellerhoff, Michael; Schwab, Stefan; Doerfler, Arnd

    2011-04-01

    We tested the hypothesis that Flat Detector computed tomography (FD-CT) with intravenous contrast medium would allow the calculation of whole brain cerebral blood volume (CBV) mapping (FD-CBV) and would correlate with multislice Perfusion CT (PCT). Twenty five patients were investigated with FD-CBV and PCT. Correlation of the CBV maps of both techniques was carried out with measurements from six anatomical regions from both sides of the brain. Mean values of each region and the correlation coefficient were calculated. Bland-Altman analysis was performed to compare the two different imaging techniques. The image and data quality of both PCT and FD-CBV were suitable for evaluation in all patients. The mean CBV values of FD-CBV and PCT showed only minimal differences with overlapping standard deviation. The correlation coefficient was 0.79 (p < 0.01). Bland-Altman analysis showed a mean difference of -0.077 ± 0.48 ml/100 g between FD-CBV and PCT CBV measurements, indicating that FD-CBV values were only slightly lower than those of PCT. CBV mapping with intravenous contrast medium using Flat Detector CT compared favourably with multislice PCT. The ability to assess cerebral perfusion within the angiographic suite may improve the management of ischaemic stroke and evaluation of the efficacy of dedicated therapies.

  17. Accuracy of Intraoperative Computed Tomography during Deep Brain Stimulation Procedures: Comparison with Postoperative Magnetic Resonance Imaging

    PubMed Central

    Bot, Maarten; van den Munckhof, Pepijn; Bakay, Roy; Stebbins, Glenn; Verhagen Metman, Leo

    2017-01-01

    Objective To determine the accuracy of intraoperative computed tomography (iCT) in localizing deep brain stimulation (DBS) electrodes by comparing this modality with postoperative magnetic resonance imaging (MRI). Background Optimal lead placement is a critical factor for the outcome of DBS procedures and preferably confirmed during surgery. iCT offers 3-dimensional verification of both microelectrode and lead location during DBS surgery. However, accurate electrode representation on iCT has not been extensively studied. Methods DBS surgery was performed using the Leksell stereotactic G frame. Stereotactic coordinates of 52 DBS leads were determined on both iCT and postoperative MRI and compared with intended final target coordinates. The resulting absolute differences in X (medial-lateral), Y (anterior-posterior), and Z (dorsal-ventral) coordinates (ΔX, ΔY, and ΔZ) for both modalities were then used to calculate the euclidean distance. Results Euclidean distances were 2.7 ± 1.1 and 2.5 ± 1.2 mm for MRI and iCT, respectively (p = 0.2). Conclusion Postoperative MRI and iCT show equivalent DBS lead representation. Intraoperative localization of both microelectrode and DBS lead in stereotactic space enables direct adjustments. Verification of lead placement with postoperative MRI, considered to be the gold standard, is unnecessary. PMID:28601874

  18. Structural Comparison between the Right and Left Atrial Appendages Using Multidetector Computed Tomography

    PubMed Central

    Shinoda, Koichi; Fukuoka, Daisuke; Torii, Ryo; Watanabe, Tsuneo; Nakano, Takashi

    2016-01-01

    The three-dimensional (3D) structures of the right atrial appendage (RAA) and left atrial appendage (LAA) were compared to clarify why thrombus formation less frequently occurs in RAA than in LAA. Morphological differences between RAA and LAA of 34 formalin-preserved cadaver hearts were investigated. Molds of RAA and LAA specimens were made and the neck areas, volumes of the atrial appendages (AA), and amount of pectinate muscles (PMs) were analyzed using multidetector computed tomography. In RAA, most PMs were connected to one another and formed a “dendritic” appearance and the inner surface area was smaller than in LAA. RAA had smaller volumes and larger neck areas than LAA. The ratios of the neck area/volume were larger and the amounts of PMs were smaller in RAA than in LAA. The volumes, neck areas, and amount of PMs of RAA were significantly correlated with those of LAA. According to the 3D structure, RAA appears to be suited for a more favorable blood flow, which may explain why the thrombus formation is less common in RAA than in LAA. Examining not only LAA but also RAA by transesophageal echocardiography may be useful in high-risk patients of thrombus formation in LAA because the volume, neck area, and amount of PMs of LAA reflect the shape of RAA. PMID:27900330

  19. Multiphase computed tomography of malignant kidney tumors: radiologic-pathologic comparison.

    PubMed

    Zokalj, Ivan; Marotti, Miljenko; Saghir, Hussein; Gasparov, Slavko; Kolarić, Branko; Plesnar, Antonio

    2012-12-01

    The aim of this retrospective study was to evaluate diagnostic test parameters of multiphase spiral computed tomography (CT) of the kidneys in the assessment of malignant renal tumors. Fifty-one patient records were reviewed. The imaging protocol included unenhanced and postcontrast scans during arterial and nephrographic phase. CT findings were compared with pathology findings to assess the value of spiral CT (sensitivity, specificity, negative predictive value, positive predictive value and accuracy) in the detection and characterization of tumors, and in the evaluation of local extension of malignant renal tumors. Spiral CT had a 96.08% sensitivity and accuracy in the detection of tumors. Characterization of renal tumors with CT had a sensitivity of 94.12% and accuracy of 96.08%. In the detection of fibrous capsule penetration, CT reached a sensitivity of 91.97% and specificity of 51.28%. In the evaluation of canal system propagation, the sensitivity was 100% and specificity 90.70%. CT had a sensitivity of 75%, specificity of 95.75% and positive predictive value of 60% in the evaluation of regional lymph node involvement. In the detection of the main renal vein invasion, CT showed 60% sensitivity and 100% specificity. Spearman's rank correlation coefficient between the mean tumor size on CT images and renal specimen was 0.916. In conclusion, multiphase spiral CT has satisfactory diagnostic parameters in the detection, characterization and evaluation of local extension of renal tumors except for detection of the main renal vein invasion.

  20. Comparison of spectral-domain and time-domain optical coherence tomography in solar retinopathy.

    PubMed

    Cho, Han Joo; Yoo, Eun Seok; Kim, Chul Gu; Kim, Jong Woo

    2011-08-01

    The purpose of this article is to compare spectral-domain (SD) and time-domain (TD) optical coherence tomography (OCT) findings in patients with solar retinopathy. Complete ocular examinations and OCT were performed in two patients presenting with acute solar retinopathy soon after observation of an eclipse. Both patients were evaluated with SD-OCT and TD-OCT at the same time. SD-OCT demonstrated characteristic defects at the level of the inner and outer segment junction of the photoreceptors in all the affected eyes and decreased reflectiveness of the retinal pigment epithelium layer. TD-OCT images showed unremarkable findings in two eyes with deteriorated visual acuity. SD-OCT improves diagnosis and assessment of the degree and nature of foveal damage in patients with solar retinopathy and may be an important tool for use in identifying foveal damage not detected by TD-OCT. SD-OCT may be preferable to TD-OCT for confirmation or assessment of the degree of foveal damage in patients with solar retinopathy.

  1. Methods and algorithms for optical coherence tomography-based angiography: a review and comparison

    PubMed Central

    Zhang, Anqi; Zhang, Qinqin; Chen, Chieh-Li; Wang, Ruikang K.

    2015-01-01

    Abstract. Optical coherence tomography (OCT)-based angiography is increasingly becoming a clinically useful and important imaging technique due to its ability to provide volumetric microvascular networks innervating tissue beds in vivo without a need for exogenous contrast agent. Numerous OCT angiography algorithms have recently been proposed for the purpose of contrasting microvascular networks. A general literature review is provided on the recent progress of OCT angiography methods and algorithms. The basic physics and mathematics behind each method together with its contrast mechanism are described. Potential directions for future technical development of OCT based angiography is then briefly discussed. Finally, by the use of clinical data captured from normal and pathological subjects, the imaging performance of vascular networks delivered by the most recently reported algorithms is evaluated and compared, including optical microangiography, speckle variance, phase variance, split-spectrum amplitude decorrelation angiography, and correlation mapping. It is found that the method that utilizes complex OCT signal to contrast retinal blood flow delivers the best performance among all the algorithms in terms of image contrast and vessel connectivity. The purpose of this review is to help readers understand and select appropriate OCT angiography algorithm for use in specific applications. PMID:26473588

  2. Comparison of fluorescein angiography and optical coherence tomography for patients with choroidal neovascularization after photodynamic therapy.

    PubMed

    Eter, Nicole; Spaide, Richard F

    2005-09-01

    To investigate retinal morphology by means of fluorescein angiography (FA) and optical coherence tomography (OCT) in patients who had undergone photodynamic therapy (PDT) with verteporfin at their 3-month-interval examination. Sixty patients with predominantly classic choroidal neovascularization (CNV) secondary to age-related macular degeneration were evaluated with FA and OCT 3 months after their last PDT. FA images were evaluated in a masked fashion for staining of and leakage from the lesion and also for cystoid loculation of fluorescein in the macula. OCT was used to evaluate foveal thickness and the presence of subretinal fluid or cystoid spaces within the retina, also in a masked fashion. The median age of the 60 patients was 78 years, and the median visual acuity of the eyes examined was 20/100. The median number of previous PDT sessions was 2. Fluorescein staining was seen in 57 eyes (95%), and fluorescein leakage was seen in 50 eyes (83%). Cystoid loculation of fluorescein was seen in 21 eyes (35%). By OCT, cystoid spaces in the macula were seen in 42 patients (70%), and subretinal fluid was seen in 15 patients (25%). Leakage seen shown by FA was correlated with the OCT finding of cystoid spaces but not with the OCT finding of subretinal fluid. Some patients had leakage during FA that did not have any observable induced OCT abnormality attributable to fluid accumulation. After PDT leakage from CNV seen during FA is associated with intraretinal fluid, often seen in loculated cystoid spaces, but not with subretinal fluid.

  3. Blockface histology with optical coherence tomography: a comparison with Nissl staining.

    PubMed

    Magnain, Caroline; Augustinack, Jean C; Reuter, Martin; Wachinger, Christian; Frosch, Matthew P; Ragan, Timothy; Akkin, Taner; Wedeen, Van J; Boas, David A; Fischl, Bruce

    2014-01-01

    Spectral domain optical coherence tomography (SD-OCT) is a high resolution imaging technique that generates excellent contrast based on intrinsic optical properties of the tissue, such as neurons and fibers. The SD-OCT data acquisition is performed directly on the tissue block, diminishing the need for cutting, mounting and staining. We utilized SD-OCT to visualize the laminar structure of the isocortex and compared cortical cytoarchitecture with the gold standard Nissl staining, both qualitatively and quantitatively. In histological processing, distortions routinely affect registration to the blockface image and prevent accurate 3D reconstruction of regions of tissue. We compared blockface registration to SD-OCT and Nissl, respectively, and found that SD-OCT-blockface registration was significantly more accurate than Nissl-blockface registration. Two independent observers manually labeled cortical laminae (e.g. III, IV and V) in SD-OCT images and Nissl stained sections. Our results show that OCT images exhibit sufficient contrast in the cortex to reliably differentiate the cortical layers. Furthermore, the modalities were compared with regard to cortical laminar organization and showed good agreement. Taken together, these SD-OCT results suggest that SD-OCT contains information comparable to standard histological stains such as Nissl in terms of distinguishing cortical layers and architectonic areas. Given these data, we propose that SD-OCT can be used to reliably generate 3D reconstructions of multiple cubic centimeters of cortex that can be used to accurately and semi-automatically perform standard histological analyses.

  4. Modelling Random Coincidences in Positron Emission Tomography by Using Singles and Prompts: A Comparison Study

    PubMed Central

    2016-01-01

    Random coincidences degrade the image in Positron Emission Tomography, PET. To compensate for their degradation effects, the rate of random coincidences should be estimated. Under certain circumstances, current estimation methods fail to provide accurate results. We propose a novel method, “Singles–Prompts” (SP), that includes the information conveyed by prompt coincidences and models the pile–up. The SP method has the same structure than the well-known “Singles Rate” (SR) approach. Hence, SP can straightforwardly replace SR. In this work, the SP method has been extensively assessed and compared to two conventional methods, SR and the delayed window (DW) method, in a preclinical PET scenario using Monte–Carlo simulations. SP offers accurate estimates for the randoms rates, while SR and DW tend to overestimate the rates (∼10%, and 5%, respectively). With pile-up, the SP method is more robust than SR (but less than DW). At the image level, the contrast is overestimated in SR-corrected images, +16%, while SP produces the correct value. Spill–over is slightly reduced using SP instead of SR. The DW images values are similar to those of SP except for low-statistic scenarios, where DW behaves as if randoms were not compensated for. In particular, the contrast is reduced, −16%. In general, the better estimations of SP translate into better image quality. PMID:27603143

  5. Comparison of three image segmentation techniques for target volume delineation in positron emission tomography.

    PubMed

    Drever, Laura A; Roa, Wilson; McEwan, Alexander; Robinson, Don

    2007-03-09

    Incorporation of positron emission tomography (PET) data into radiotherapy planning is currently under investigation for numerous sites including lung, brain, head and neck, breast, and prostate. Accurate tumor-volume quantification is essential to the proper utilization of the unique information provided by PET. Unfortunately,target delineation within PET currently remains a largely unaddressed problem. We therefore examined the ability of three segmentation methods-thresholding, Sobel edge detection, and the watershed approach-to yield accurate delineation of PET target cross-sections. A phantom study employing well-defined cylindrical and spherical volumes and activity distributions provided an opportunity to assess the relative efficacy with which the three approaches could yield accurate target delineation in PET. Results revealed that threshold segmentation can accurately delineate target cross-sections, but that the Sobel and watershed techniques both consistently fail to correctly identify the size of experimental volumes. The usefulness of threshold-based segmentation is limited, however, by the dependence of the correct threshold (that which returns the correct area at each image slice) on target size.

  6. Magnetic resonance imaging of pulmonary infection in immunocompromised children: comparison with multidetector computed tomography.

    PubMed

    Ozcan, H Nursun; Gormez, Ayşegul; Ozsurekci, Yasemin; Karakaya, Jale; Oguz, Berna; Unal, Sule; Cetin, Mualla; Ceyhan, Mehmet; Haliloglu, Mithat

    2017-02-01

    Computed tomography (CT) is commonly used to detect pulmonary infection in immunocompromised children. To compare MRI and multidetector CT findings of pulmonary abnormalities in immunocompromised children. Seventeen neutropaenic children (6 girls; ages 2-18 years) were included. Non-contrast-enhanced CT was performed with a 64-detector CT scanner. Axial and coronal non-enhanced thoracic MRI was performed using a 1.5-T scanner within 24 h of the CT examination (true fast imaging with steady-state free precession, fat-saturated T2-weighted turbo spin echo with motion correction, T2-weighted half-Fourier single-shot turbo spin echo [HASTE], fat-saturated T1-weighted spoiled gradient echo). Pulmonary abnormalities (nodules, consolidations, ground glass opacities, atelectasis, pleural effusion and lymph nodes) were evaluated and compared among MRI sequences and between MRI and CT. The relationship between MRI sequences and nodule sizes was examined by chi- square test. Of 256 CT lesions, 207 (81%, 95% confidence interval [CI] 76-85%) were detected at MRI. Of 202 CT-detected nodules, 157 (78%, 95% CI 71-83%) were seen at motion-corrected MRI. Of the 1-5-mm nodules, 69% were detected by motion-corrected T2-weighted MRI and 38% by HASTE MRI. Sensitivity of MRI (both axial fat-saturated T2-weighted turbo spin echo with variable phase encoding directions (BLADE) images and HASTE sequences) to detect pulmonary abnormalities is promising.

  7. Comparison of three-dimensional optical coherence tomography and high resolution photography for art conservation studies.

    PubMed

    Adler, Desmond C; Stenger, Jens; Gorczynska, Iwona; Lie, Henry; Hensick, Teri; Spronk, Ron; Wolohojian, Stephan; Khandekar, Narayan; Jiang, James Y; Barry, Scott; Cable, Alex E; Huber, Robert; Fujimoto, James G

    2007-11-26

    Gold punchwork and underdrawing in Renaissance panel paintings are analyzed using both three-dimensional swept source / Fourier domain optical coherence tomography (3D-OCT) and high resolution digital photography. 3D-OCT can generate en face images with micrometer-scale resolutions at arbitrary sectioning depths, rejecting out-of-plane light by coherence gating. Therefore 3D-OCT is well suited for analyzing artwork where a surface layer obscures details of interest. 3D-OCT also enables cross-sectional imaging and quantitative measurement of 3D features such as punch depth, which is beneficial for analyzing the tools and techniques used to create works of art. High volumetric imaging speeds are enabled by the use of a Fourier domain mode locked (FDML) laser as the 3D-OCT light source. High resolution infrared (IR) digital photography is shown to be particularly useful for the analysis of underdrawing, where the materials used for the underdrawing and paint layers have significantly different IR absrption properties. In general, 3D-OCT provides a more flexible and comprehensive analysis of artwork than high resolution photography, but also requires more complex instrumentation and data analysis.

  8. Comparison of Artemis 2 Ultrasound and Visante Optical Coherence Tomography Corneal Thickness Profiles

    PubMed Central

    Ursea, Roxana; Feng, Matthew; Urs, Raksha; RoyChoudhury, Arindam; Silverman, Ronald H.

    2013-01-01

    PURPOSE To compare corneal thickness profiles of cross-sections of cornea determined by arc-scanned immersion ultrasound and optical coherence tomography (OCT). METHODS Corneas of 28 eyes from 14 participants were scanned in triplicate using the Artemis 2 high-frequency arc-scanned ultrasound system (ArcScan Inc) and the Visante OCT system (Carl Zeiss Meditec). Corneal thickness and reproducibility were compared within 3.5 mm of central cornea in the horizontal plane. RESULTS Although highly correlated, Visante central and peripheral corneal thickness values were systematically thinner than Artemis 2 values. Within the central 0.5 mm, the difference was approximately 8 μm, but the difference increased with distance from the center. Reproducibility for each instrument was comparable, measuring <4 μm centrally and increasing peripherally. CONCLUSIONS Visante OCT measurements of corneal thickness are thinner than Artemis 2 ultrasound values centrally with an increasing difference with peripheral position. Measurement reproducibility was comparable for the two techniques. PMID:23205905

  9. Comparison of artemis 2 ultrasound and Visante optical coherence tomography corneal thickness profiles.

    PubMed

    Ursea, Roxana; Feng, Matthew; Urs, Raksha; RoyChoudhury, Arindam; Silverman, Ronald H

    2013-01-01

    To compare corneal thickness profiles of cross-sections of cornea determined by arc-scanned immersion ultrasound and optical coherence tomography (OCT). Corneas of 28 eyes from 14 participants were scanned in triplicate using the Artemis 2 high-frequency arc-scanned ultrasound system (ArcScan Inc) and the Visante OCT system (Carl Zeiss Meditec). Corneal thickness and reproducibility were compared within 3.5 mm of central cornea in the horizontal plane. Although highly correlated, Visante central and peripheral corneal thickness values were systematically thinner than Artemis 2 values. Within the central 0.5 mm, the difference was approximately 8 μm, but the difference increased with distance from the center. Reproducibility for each instrument was comparable, measuring <4 μm centrally and increasing peripherally. Visante OCT measurements of corneal thickness are thinner than Artemis 2 ultrasound values centrally with an increasing difference with peripheral position. Measurement reproducibility was comparable for the two techniques. Copyright 2013, SLACK Incorporated.

  10. Comparison of electrical capacitance tomography & gamma densitometer measurement in viscous oil-gas flows

    NASA Astrophysics Data System (ADS)

    Archibong Eso, A.; Zhao, Yabin; Yeung, Hoi

    2014-04-01

    Multiphase flow is a common occurrence in industries such as nuclear, process, oil & gas, food and chemical. A prior knowledge of its features and characteristics is essential in the design, control and management of such processes due to its complex nature. Electrical Capacitance Tomography (ECT) and Gamma Densitometer (Gamma) are two promising approaches for multiphase visualization and characterization in process industries. In two phase oil & gas flow, ECT and Gamma are used in multiphase flow monitoring techniques due to their inherent simplicity, robustness, and an ability to withstand wide range of operational temperatures and pressures. High viscous oil (viscosity > 100 cP) is of interest because of its huge reserves, technological advances in its production and unlike conventional oil (oil viscosity < 100 cP) and gas flows where ECT and Gamma have been previously used, high viscous oil and gas flows comes with certain associated concerns which include; increased entrainment of gas bubbles dispersed in oil, shorter and more frequent slugs as well as oil film coatings on the walls of flowing conduits. This study aims to determine the suitability of both devices in the visualization and characterization of high-viscous oil and gas flow. Static tests are performed with both devices and liquid holdup measurements are obtained. Dynamic experiments were also conducted in a 1 & 3 inch facility at Cranfield University with a range of nominal viscosities (1000, 3000 & 7500 cP). Plug, slug and wavy annular flow patterns were identified by means of Probability Mass Function and time series analysis of the data acquired from Gamma and ECT devices with high speed camera used to validate the results. Measured Liquid holdups for both devices were also compared.

  11. Comparison of optical coherence tomography and scanning laser polarimetry measurements in patients with multiple sclerosis.

    PubMed

    Quelly, Amanda; Cheng, Han; Laron, Michal; Schiffman, Jade S; Tang, Rosa A

    2010-08-01

    To compare optical coherence tomography (OCT) and scanning laser polarimetry (GDx) measurements of the retinal nerve fiber layer (RNFL) in multiple sclerosis (MS) patients with and without optic neuritis (ON). OCT and GDx were performed on 68 MS patients. Qualifying eyes were divided into two groups: 51 eyes with an ON history > or =6 months before (ON eyes) and 65 eyes with no history of ON (non-ON eyes). Several GDx and OCT parameters and criteria were used to define an eye as abnormal, for example, GDx nerve fiber indicator (NFI) >20 or 30, OCT average RNFL thickness, and GDx temporal-superior-nasal-inferior-temporal average (TSNIT) below 5 or 1% of the normative database of the instruments. Agreement between OCT and GDx parameters was reported as percent of observed agreement, along with the AC1 statistic. Linear regression analyses were used to examine the relationship between OCT average RNFL thickness and GDx NFI and TSNIT. All OCT and GDx measurements showed significantly more RNFL damage in ON than in non-ON eyes. Agreement between OCT and GDx parameters ranged from 69 to 90% (AC1 0.37 to 0.81) in ON eyes and 52 to 91% (AC1 = 0.21 to 0.90) in non-ON eyes. Best agreement was observed between OCT average RNFL thickness (p < 0.01) and NFI (>30) in ON eyes (90%, AC1 = 0.81) and between OCT average RNFL thickness (p < 0.01) and GDx TSNIT average (p < 0.01) in non-ON eyes (91%, AC1 = 0.90). In ON eyes, the OCT average RNFL thickness showed good linear correlation with NFI (R = 0.69, p < 0.0001) and TSNIT (R = 0.55, p < 0.0001). OCT and GDx show good agreement and can be useful in detecting RNFL loss in MS/ON eyes.

  12. Comparison of electrical capacitance tomography and gamma densitometer measurement in viscous oil-gas flows

    SciTech Connect

    Archibong Eso, A.; Zhao, Yabin; Yeung, Hoi

    2014-04-11

    Multiphase flow is a common occurrence in industries such as nuclear, process, oil and gas, food and chemical. A prior knowledge of its features and characteristics is essential in the design, control and management of such processes due to its complex nature. Electrical Capacitance Tomography (ECT) and Gamma Densitometer (Gamma) are two promising approaches for multiphase visualization and characterization in process industries. In two phase oil and gas flow, ECT and Gamma are used in multiphase flow monitoring techniques due to their inherent simplicity, robustness, and an ability to withstand wide range of operational temperatures and pressures. High viscous oil (viscosity > 100 cP) is of interest because of its huge reserves, technological advances in its production and unlike conventional oil (oil viscosity < 100 cP) and gas flows where ECT and Gamma have been previously used, high viscous oil and gas flows comes with certain associated concerns which include; increased entrainment of gas bubbles dispersed in oil, shorter and more frequent slugs as well as oil film coatings on the walls of flowing conduits. This study aims to determine the suitability of both devices in the visualization and characterization of high-viscous oil and gas flow. Static tests are performed with both devices and liquid holdup measurements are obtained. Dynamic experiments were also conducted in a 1 and 3 inch facility at Cranfield University with a range of nominal viscosities (1000, 3000 and 7500 cP). Plug, slug and wavy annular flow patterns were identified by means of Probability Mass Function and time series analysis of the data acquired from Gamma and ECT devices with high speed camera used to validate the results. Measured Liquid holdups for both devices were also compared.

  13. COMPARISON OF COMPUTED TOMOGRAPHY AND ABDOMINAL RADIOGRAPHY FOR DETECTION OF CANINE MECHANICAL INTESTINAL OBSTRUCTION.

    PubMed

    Drost, Wm Tod; Green, Eric M; Zekas, Lisa J; Aarnes, Turi K; Su, Lillian; Habing, Gregory G

    2016-07-01

    Vomiting, often caused by mechanical intestinal obstruction, is common in dogs. Equivocal radiographic signs often necessitate repeat radiographs or additional imaging procedures. For our prospective, case-controlled, accuracy study, we hypothesized the following: (1) using computed tomography (CT), radiologists will be more sensitive and specific for detecting mechanical intestinal obstruction and recommending surgery compared to using radiographs; and (2) using measurements, radiologists will be more sensitive and specific using radiographs or CT for detecting mechanical intestinal obstruction and recommending surgery. Twenty dogs had abdominal radiographs and abdominal CT. Seventeen dogs had abdominal surgery and three dogs were not obstructed based on clinical follow-up. Confidence levels (five-point scale) of three experienced radiologists for mechanical intestinal obstruction and recommending surgery were recorded before and after making selected measurements. Eight dogs had surgically confirmed mechanical intestinal obstruction, and 12 dogs did not have obstruction. For detecting mechanical intestinal obstruction, CT was more sensitive (95.8% vs. 79.2%) and specific (80.6% vs. 69.4%) compared to radiographs, but the difference was not statistically significant. For recommending surgery, radiography was more sensitive (91.7% vs. 83.3%) and specific (83.3% vs. 72.2%) than using CT, but differences were not statistically significant. We reported objective CT measurements for predicting small mechanical intestinal obstruction. By incorporating these objective data, the diagnosis of mechanical intestinal obstruction changed in five of 120 instances (radiographs and CT). In no instance (0/120), did the objective data change the recommendation for surgery. Using CT or abdominal radiographs for the detection of canine mechanical intestinal obstruction is sensitive and specific when evaluated by experienced veterinary radiologists. © 2016 American College of

  14. Comparison of Optical Coherence Tomography and Scanning Laser Polarimetry Measurements in Patients with Multiple Sclerosis

    PubMed Central

    Quelly, Amanda; Cheng, Han; Laron, Michal; Schiffman, Jade S.; Tang, Rosa A.

    2010-01-01

    Purpose To compare optical coherence tomography (OCT) and scanning laser polarimetry (GDx) measurements of the retinal nerve fiber layer (RNFL) in multiple sclerosis (MS) patients with and without optic neuritis (ON). Methods OCT and GDx were performed on 68 MS patients. Qualifying eyes were divided into two groups: 51 eyes with an ON history ≥ 6 months prior (ON eyes), and 65 eyes with no history of ON (non-ON eyes). Several GDx and OCT parameters and criteria were used to define an eye as abnormal, for example, GDx nerve fiber indicator (NFI) above 20 or 30, OCT average RNFL thickness and GDx temporal-superior-nasal-inferior-temporal average (TSNIT) below 5% or 1% of the instruments’ normative database. Agreement between OCT and GDx parameters was reported as percent of observed agreement, along with the AC1 statistic. Linear regression analyses were used to examine the relationship between OCT average RNFL thickness and GDx NFI and TSNIT. Results All OCT and GDx measurements showed significantly more RNFL damage in ON than in non-ON eyes. Agreement between OCT and GDx parameters ranged from 69–90% (AC1 0.37–0.81) in ON eyes, and 52–91% (AC1 = 0.21–0.90) in non-ON eyes. Best agreement was observed between OCT average RNFL thickness (P < 0.01) and NFI (>30) in ON eyes (90%, AC1 = 0.81), and between OCT average RNFL thickness (P < 0.01) and GDx TSNIT average (P < 0.01) in non-ON eyes (91%, AC1 = 0.90). In ON eyes, the OCT average RNFL thickness showed good linear correlation with NFI (R2 = 0.69, P < 0.0001) and TSNIT (R2 = 0.55, P < 0.0001). Conclusions OCT and GDx show good agreement and can be useful in detecting RNFL loss in MS/ON eyes. PMID:20495500

  15. The comparison of manual vs automated disc margin delineation using spectral-domain optical coherence tomography

    PubMed Central

    Iverson, S M; Sehi, M

    2013-01-01

    Aims To examine the impact of manual vs automated disc margin delineation on optic nerve head (ONH) and retinal nerve fiber layer (RNFL) parameters using spectral-domain optical coherence tomography (SDOCT). Methods A prospective cohort study consisting of normal, glaucoma suspect (GS) and glaucoma patients who underwent ONH and RNFL measurements using SDOCT technology (RTVue; Optovue Inc.). The retinal pigment epithelium/Bruch's membrane (RPE/BM) complex end points were automatically determined first, and were manually redefined subsequently. Analysis of variance, coefficient of variation (COV), concordance correlation coefficient (CCC), and Bland–Altman plots were used for the analyses. Results Ninety-nine eyes of 50 subjects (age 68±10 years) consisting of 36 glaucoma, 56 GS, and 7 normal eyes were included. The RNFL thickness measurements were similar (P>0.05) between the two methods of demarcation, except for the inferior-nasal sector (P=0.04). For the ONH measurements, the cup-to-disc (C/D) ratio and rim area showed significant differences between the two methods (P<0.001). COV/CCC values for the ONH parameters were as follows: cup area 17.6%/0.88; cup volume 7.4%/0.91; average C/D ratio 18.1%/0.78; rim area 25.3%/0.69; and rim volume 42.6%/0.71, respectively. CCC/COV values for the RNFL parameters were as follows: average 2.1%/0.98; inferior-temporal quadrant 8.1%/0.79; inferior-nasal quadrant INQ quadrant 12.6%/0.67; SNQ quadrant 7.8%/0.83; and STQ quadrant 7.8%/0.88, respectively. Conclusion An overall high agreement and moderate–substantial concordance was observed between the demarcation methods. Automated disc margin delineation of SDOCT can be used reliably in clinical practice. PMID:23907624

  16. Comparison of Thoracic Radiography and Computed Tomography in Calves with Naturally Occurring Respiratory Disease.

    PubMed

    Fowler, Jennifer; Stieger-Vanegas, Susanne M; Vanegas, Jorge A; Bobe, Gerd; Poulsen, Keith P

    2017-01-01

    To evaluate the severity and extent of lung disease using thoracic computed radiography (CR) compared to contrast-enhanced multi-detector computed tomography (MDCT) of the thorax in calves with naturally occurring respiratory disease and to evaluate the feasibility and safety of performing contrast-enhanced thoracic multi-detector MDCT examinations in sedated calves. Furthermore, to evaluate if combining CR or MDCT with respiratory scoring factors will improve prediction of the chronicity of pulmonary disease in calves. Thirty Jersey heifer calves ranging in age between 25 and 89 days with naturally occurring respiratory disease. All calves were evaluated via thoracic CR and contrast-enhanced MDCT. All calves were euthanized immediately following thoracic MDCT and submitted for necropsy. Imaging and histopathology results were compared with each other. Thoracic MDCT was superior for evaluation of pneumonia in calves due to the lack of summation in all areas of the lungs. Intravenously administered sedation provided an adequate plane of sedation for acquiring MDCT images of diagnostic quality, without the need for re-scanning. A diagnosis of pneumonia was made with equal rate on both thoracic CR and MDCT. Although mild differences in classification of lung pattern and extent of lung disease were seen when comparing an experienced and a less experienced evaluator, the overall differences were not statistically significant. The best intra- and inter-observer agreement was noted when evaluating the cranioventral aspects of the lungs in either modality. Clinical respiratory scoring is inadequate for diagnosing chronicity of pneumonia in calves with naturally occurring pneumonia. Both imaging modalities allowed diagnosis of pneumonia in calves. The cranial ventral aspects of the lungs were most commonly affected. Thoracic CR and MDCT provided similar diagnostic effectiveness in diagnosing pneumonia. However, MDCT provided better assessment of subtle details, which may

  17. Simulation of photoacoustic tomography (PAT) system in COMSOL and comparison of two popular reconstruction techniques

    NASA Astrophysics Data System (ADS)

    Sowmiya, C.; Thittai, Arun K.

    2017-03-01

    Photoacoustic imaging is a molecular cum functional imaging modality based on differential optical absorption of the incident laser pulse by the endogeneous tissue chromophores. Several numerical simulations and finite element models have been developed in the past to describe and study Photoacoustic (PA) signal generation principles and study the effect of variation in PA parameters. Most of these simulation work concentrate on analyzing extracted 1D PA signals and each of them mostly describe only few of the building blocks of a Photoacoustic Tomography (PAT) imaging system. Papers describing simulation of the entire PAT system in one simulation platform, along with reconstruction is seemingly rare. This study attempts to describe how a commercially available Finite Element software (COMSOL(R)), can serve as a single platform for simulating PAT that couples the electromagnetic, thermodynamic and acoustic pressure physics involved in PA phenomena. Further, an array of detector elements placed at the boundary in the FE model can provide acoustic pressure data that can be exported to Matlab(R) to perform tomographic image reconstruction. The performance of two most commonly used image reconstruction techniques; namely, Filtered Backprojection (FBP) and Synthetic Aperture (SA) beamforming are compared. Results obtained showed that the lateral resolution obtained using FBP vs. SA largely depends on the aperture parameters. FBP reconstruction was able to provide a slightly better lateral resolution for smaller aperture while SA worked better for larger aperture. This interesting effect is currently being investigated further. Computationally FBP was faster, but it had artifacts along the spherical shell on which the data is projected.

  18. Optical Coherence Tomography Angiography in Mice: Comparison with Confocal Scanning Laser Microscopy and Fluorescein Angiography

    PubMed Central

    Giannakaki-Zimmermann, Helena; Kokona, Despina; Wolf, Sebastian; Ebneter, Andreas; Zinkernagel, Martin S.

    2016-01-01

    Purpose Optical coherence tomography angiography (OCT-A) allows noninvasive visualization of retinal vessels in vivo. OCT-A was used to characterize the vascular network of the mouse retina and was compared with fluorescein angiography (FA) and histology. Methods In the present study, OCT-A based on a Heidelberg Engineering Spectralis system was used to investigate the vascular network in mice. Data was compared with FA and confocal microscopy of flat-mount histology stained with isolectin IB4. For quantitative analysis the National Cancer Institute's AngioTool software was used. Vessel density, the number of vessel junctions, and endpoints were measured and compared between the imaging modalities. Results The configuration of the superficial capillary network was comparable with OCT-A and flat-mount histology in BALBc mice. However, vessel density and the number of vessel junctions per region of interest (P = 0.0161 and P = 0.0015, respectively) in the deep vascular network of BALBc mice measured by OCT-A was significantly higher than with flat-mount histology. In C3A.Cg-Pde6b+Prph2Rd2/J mice, where the deep capillary plexus is absent, analysis of the superficial network provided similar results for all three imaging modalities. Conclusion OCT-A is a helpful imaging tool for noninvasive, in vivo imaging of the vascular plexus in mice. It may offer advantages over FA and confocal microscopy especially for imaging the deep vascular plexus. Translational Relevance The present study shows that OCT-A can be employed for small animal imaging to assess the vascular network and offers advantages over flat-mount histology and FA. PMID:27570710

  19. Ultrasonography in the diagnosis of nasal bone fractures: a comparison with conventional radiography and computed tomography.

    PubMed

    Lee, In Sook; Lee, Jung-Hoon; Woo, Chang-Ki; Kim, Hak Jin; Sol, Yu Li; Song, Jong Woon; Cho, Kyu-Sup

    2016-02-01

    The purpose of this study was to evaluate and compare the diagnostic efficacy of ultrasonography (US) with radiography and multi-detector computed tomography (CT) for the detection of nasal bone fractures. Forty-one patients with a nasal bone fracture who underwent prospective US examinations were included. Plain radiographs and CT images were obtained on the day of trauma. For US examinations, radiologist used a linear array transducer (L17-5 MHz) in 24 patients and hockey-stick probe (L15-7 MHz) in 17. The bony component of the nose was divided into three parts (right and left lateral nasal walls, and midline of nasal bone). Fracture detection by three modalities was subjected to analysis. Furthermore, findings made by each modality were compared with intraoperative findings. Nasal bone fractures were located in the right lateral wall (n = 28), midline of nasal bone (n = 31), or left lateral wall (n = 31). For right and left lateral nasal walls, CT had greater sensitivity and specificity than US or radiography, and better agreed with intraoperative findings. However, for midline fractures of nasal bone, US had higher specificity, positive predictive value, and negative predictive value than CT. Although two US evaluations showed good agreements at all three sites, US findings obtained by the hockey-stick probe showed closer agreement with intraoperative findings for both lateral nasal wall and midline of nasal bone. Although CT showed higher sensitivity and specificity than US or radiography, US found to be helpful for evaluating the midline of nasal bone. Furthermore, for US examinations of the nasal bone, a smaller probe and higher frequency may be required.

  20. Comparison of retinal vessel measurements using adaptive optics scanning laser ophthalmoscopy and optical coherence tomography.

    PubMed

    Arichika, Shigeta; Uji, Akihito; Ooto, Sotaro; Muraoka, Yuki; Yoshimura, Nagahisa

    2016-05-01

    We compared adaptive optics scanning laser ophthalmoscopy (AOSLO) and optical coherence tomography (OCT) vessel caliber measurements. AOSLO videos were acquired from 28 volunteers with healthy eyes. Artery measurements were made 0.5-1 disc diameters away from the optic disc margin. Individual segmented retinal arterial caliber was measured in synchronization with cardiac pulsation and averaged to obtain final horizontal retinal arterial caliber (ACH) and horizontal retinal arterial lumen (ALH). All OCT images were obtained with the Spectralis OCT, a spectral-domain OCT system. Vertical retinal arterial caliber (ACV) and vertical retinal arterial lumen (ALV) were measured on the same artery measured with AOSLO. Measurements made with the two imaging systems were compared. Average ACH, measured with AOSLO, was 123.4 ± 11.2 and average ALH was 101.8 ± 10.2 µm. Average ACV, measured with OCT, was 125.5 ± 11.4 and average ALV was 99.1 ± 10.6 µm. Both arterial caliber (r = 0.767, p < 0.0001) and arterial lumen (r = 0.81, p < 0.0001) measurements were significantly correlated between imaging modalities. Additionally, ACH and ACV were not significantly different (p = 0.16). However, ALH measurements were significantly higher than ALV measurements (p = 0.03). Vessel measurements made with AOSLO and OCT were well correlated. Moreover, plasma is visible and distinguishable from the retinal vessel wall in AOSLO images but not in OCT images. Therefore, AOSLO may measure vessel width more precisely than OCT.