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Sample records for computed tomographic analysis

  1. Computed tomographic analysis of meteorite inclusions

    NASA Technical Reports Server (NTRS)

    Arnold, J. R.; Testa, J. P., Jr.; Friedman, P. J.; Kambic, G. X.

    1983-01-01

    The feasibility of obtaining nondestructively a cross-sectional display of very dense heterogeneous rocky specimens, whether lunar, terrestrial or meteoritic, by using a fourth generation computed tomographic (CT) scanner, with modifications to the software only, is discussed. A description of the scanner, and of the experimental and analytical procedures is given. Using this technique, the interior of heterogeneous materials such as Allende can be probed nondestructively. The regions of material with high and low atomic numbers are displayed quickly; the object can then be cut to obtain for analysis just the areas of interest. A comparison of this technique with conventional industrial and medical techniques is made in terms of image resolution and density distribution display precision.

  2. Computed tomographic beam-hardening artefacts: mathematical characterization and analysis

    PubMed Central

    Park, Hyoung Suk; Chung, Yong Eun; Seo, Jin Keun

    2015-01-01

    This paper presents a mathematical characterization and analysis of beam-hardening artefacts in X-ray computed tomography (CT). In the field of dental and medical radiography, metal artefact reduction in CT is becoming increasingly important as artificial prostheses and metallic implants become more widespread in ageing populations. Metal artefacts are mainly caused by the beam-hardening of polychromatic X-ray photon beams, which causes mismatch between the actual sinogram data and the data model being the Radon transform of the unknown attenuation distribution in the CT reconstruction algorithm. We investigate the beam-hardening factor through a mathematical analysis of the discrepancy between the data and the Radon transform of the attenuation distribution at a fixed energy level. Separation of cupping artefacts from beam-hardening artefacts allows causes and effects of streaking artefacts to be analysed. Various computer simulations and experiments are performed to support our mathematical analysis. PMID:25939628

  3. Computed tomographic beam-hardening artefacts: mathematical characterization and analysis.

    PubMed

    Park, Hyoung Suk; Chung, Yong Eun; Seo, Jin Keun

    2015-06-13

    This paper presents a mathematical characterization and analysis of beam-hardening artefacts in X-ray computed tomography (CT). In the field of dental and medical radiography, metal artefact reduction in CT is becoming increasingly important as artificial prostheses and metallic implants become more widespread in ageing populations. Metal artefacts are mainly caused by the beam-hardening of polychromatic X-ray photon beams, which causes mismatch between the actual sinogram data and the data model being the Radon transform of the unknown attenuation distribution in the CT reconstruction algorithm. We investigate the beam-hardening factor through a mathematical analysis of the discrepancy between the data and the Radon transform of the attenuation distribution at a fixed energy level. Separation of cupping artefacts from beam-hardening artefacts allows causes and effects of streaking artefacts to be analysed. Various computer simulations and experiments are performed to support our mathematical analysis. PMID:25939628

  4. [Multislice computed tomographic myelography].

    PubMed

    Klingebiel, R; Masuhr, F; Rogalla, P; Hein, E; Juran, R; Bauknecht, H C; Bohner, G

    2006-02-01

    While magnetic resonance imaging (MRI) is the first line modality in depicting intramedullary spinal lesions, computed tomographic (CT) myelography has gained renewed attention due to the introduction of multislice scanning (MS-CT). Compared with conventional CT, MS-CT permits rapid, high-resolution imaging of various spinal pathologies with extended scan length. Although soft tissue contrast is inferior to that with MRI, MS-CT myelography performs best in detailed assessment of osseous pathologies, 3D imaging of orthopedic and anesthesiologic implants, and showing dural leakage and causes of CSF circulation impairment. Whenever MRI is not available or contraindicated, MS-CT myelography is the method of choice for evaluating spinal lesions. PMID:16283150

  5. Analysis of computed tomographic imaging spectrometers. I. Spatial and spectral resolution.

    PubMed

    Hagen, Nathan; Dereniak, Eustace L

    2008-10-01

    Computed tomographic imaging spectrometers measure the spectrally resolved image of an object scene in an entirely different manner from traditional whisk-broom or push-broom systems, and thus their noise behavior and data artifacts are unfamiliar. We review computed tomographic imaging spectrometry (CTIS) measurement systems and analyze their performance, with the aim of providing a vocabulary for discussing resolution in CTIS instruments, by illustrating the artifacts present in their reconstructed data and contributing a rule-of-thumb measure of their spectral resolution. We also show how the data reconstruction speed can be improved, at no cost in reconstruction quality, by ignoring redundant projections within the measured raw images. PMID:18830288

  6. Fractional Flow Reserve and Coronary Computed Tomographic Angiography: A Review and Critical Analysis.

    PubMed

    Hecht, Harvey S; Narula, Jagat; Fearon, William F

    2016-07-01

    Invasive fractional flow reserve (FFR) is now the gold standard for intervention. Noninvasive functional imaging analyses derived from coronary computed tomographic angiography (CTA) offer alternatives for evaluating lesion-specific ischemia. CT-FFR, CT myocardial perfusion imaging, and transluminal attenuation gradient/corrected contrast opacification have been studied using invasive FFR as the gold standard. CT-FFR has demonstrated significant improvement in specificity and positive predictive value compared with CTA alone for predicting FFR of ≤0.80, as well as decreasing the frequency of nonobstructive invasive coronary angiography. High-risk plaque characteristics have also been strongly implicated in abnormal FFR. Myocardial computed tomographic perfusion is an alternative method with promising results; it involves more radiation and contrast. Transluminal attenuation gradient/corrected contrast opacification is more controversial and may be more related to vessel diameter than stenosis. Important considerations remain: (1) improvement of CTA quality to decrease unevaluable studies, (2) is the diagnostic accuracy of CT-FFR sufficient? (3) can CT-FFR guide intervention without invasive FFR confirmation? (4) what are the long-term outcomes of CT-FFR-guided treatment and how do they compare with other functional imaging-guided paradigms? (5) what degree of stenosis on CTA warrants CT-FFR? (6) how should high-risk plaque be incorporated into treatment decisions? (7) how will CT-FFR influence other functional imaging test utilization, and what will be the effect on the practice of cardiology? (8) will a workstation-based CT-FFR be mandatory? Rapid progress to date suggests that CTA-based lesion-specific ischemia will be the gatekeeper to the cardiac catheterization laboratory and will transform the world of intervention. PMID:27390333

  7. Comparison between clinical indicators of transmembrane oxygenator thrombosis and multidetector computed tomographic analysis.

    PubMed

    Panigada, Mauro; L'Acqua, Camilla; Passamonti, Serena Maria; Mietto, Cristina; Protti, Alessandro; Riva, Roberto; Gattinoni, Luciano

    2015-04-01

    This study aims to assess whether multidetector computed tomography (MDCT) could accurately confirm the clinical suspicion of transmembrane oxygenator thrombosis (MOT) during extracorporeal membrane oxygenation (ECMO). Twenty-seven oxygenators were examined using MDCT at the end of patient treatment. Transmembrane oxygenator thrombosis was suspected in 15 of them according to the presence of at least 2 of the following clinical indicators: (1) increase in d-dimer, (2) decrease in platelet count, (3) decrease in oxygenator performance, and (4) presence of clots on the surface of the oxygenator. Transmembrane oxygenator thrombosis was confirmed by MDCT in 5 (33%) of them. Transmembrane oxygenator thrombosis was unexpectedly found in 5 (41%) of the remaining 12 oxygenators not suspected for MOT. Eight (80%) of these oxygenators had clots accounting for less than 1% of total volume. Clots were mainly detectable at the apical corner of the oxygenator, most likely due to greater blood stasis. We found a significant increase in d-dimer and in membrane oxygenator shunt and a decrease in platelet count from the start to the discontinuation of ECMO. Hemostatic abnormalities significantly reverted 48 hours after oxygenator removal, suggesting the role of ECMO in activation of the coagulation cascade. Multidetector computed tomographic scan could not accurately confirm the clinical suspicion of MOT. PMID:25547046

  8. Computed tomographic findings in bilateral adrenal tuberculosis

    SciTech Connect

    Wilms, G.E.; Baert, A.L.; Kint, E.J.; Pringot, J.H.; Goddeeris, P.G.

    1983-03-01

    The computed tomographic (CT) features of bilateral adrenal tuberculosis are reported in two cases that demonstrate two typical different clinical and morphological manifestations of the disease. The incidence and CT appearance of adrenal tuberculosis are discussed, with emphasis on differential diagnosis.

  9. Computed tomographic staging of traumatic epidural bleeding

    SciTech Connect

    Zimmerman, R.A.; Bilaniuk, L.T.

    1982-09-01

    The computed tomographic findings in 45 patients with post-traumatic epidural hemotomas are subdivided into three categories (acute, subacute, and chronic) and correlated with the severity of bleeding, clot formation, and clot resorption. Active epidural bleeding may be identified in acute cases.

  10. Computed tomographic evaluation of laryngoceles

    SciTech Connect

    Silverman, P.M.; Korobkin, M.

    1982-10-01

    Computed tomography (CT) of the larynx was used in three patients with laryngoceles. One of the cases is described. CT was able to define the extent of the laryngocele more precisely than either clinical examination or conventional radiographic techniques.

  11. Reciprocating vs Rotary Instrumentation in Pediatric Endodontics: Cone Beam Computed Tomographic Analysis of Deciduous Root Canals using Two Single-file Systems

    PubMed Central

    Prabhakar, Attiguppe R; Yavagal, Chandrashekar; Naik, Saraswathi V

    2016-01-01

    ABSTRACT Background: Primary root canals are considered to be most challenging due to their complex anatomy. "Wave one" and "one shape" are single-file systems with reciprocating and rotary motion respectively. The aim of this study was to evaluate and compare dentin thickness, centering ability, canal transportation, and instrumentation time of wave one and one shape files in primary root canals using a cone beam computed tomographic (CBCT) analysis. Study design: This is an experimental, in vitro study comparing the two groups. Materials and methods: A total of 24 extracted human primary teeth with minimum 7 mm root length were included in the study. Cone beam computed tomographic images were taken before and after the instrumentation for each group. Dentin thickness, centering ability, canal transportation, and instrumentation times were evaluated for each group. Results: A significant difference was found in instrumentation time and canal transportation measures between the two groups. Wave one showed less canal transportation as compared with one shape, and the mean instrumentation time of wave one was significantly less than one shape. Conclusion: Reciprocating single-file systems was found to be faster with much less procedural errors and can hence be recommended for shaping the root canals of primary teeth. How to cite this article: Prabhakar AR, Yavagal C, Dixit K, Naik SV. Reciprocating vs Rotary Instrumentation in Pediatric Endodontics: Cone Beam Computed Tomographic Analysis of Deciduous Root Canals using Two Single-File Systems. Int J Clin Pediatr Dent 2016;9(1):45-49. PMID:27274155

  12. Chronic beryllium disease: computed tomographic findings.

    PubMed

    Sharma, Nidhi; Patel, Jeet; Mohammed, Tan-Lucien H

    2010-01-01

    Chronic beryllium disease is a rare multisystem granulomatous disease predominantly involving the lungs and resulting from an immunologic response to long-term occupational exposure. Computed tomography of the chest reveals important lung parenchymal and mediastinal findings and plays an important role in the diagnosis and follow-up assessment of patients with chronic beryllium disease. Its significance lies in the exact localization and evaluation of the extent of lesions. We present an overview of the subject and a pictorial review of the spectrum of computed tomographic features of beryllium disease. PMID:21084914

  13. Computed Tomographic Image Analysis Based on FEM Performance Comparison of Segmentation on Knee Joint Reconstruction

    PubMed Central

    Jang, Seong-Wook; Seo, Young-Jin; Yoo, Yon-Sik

    2014-01-01

    The demand for an accurate and accessible image segmentation to generate 3D models from CT scan data has been increasing as such models are required in many areas of orthopedics. In this paper, to find the optimal image segmentation to create a 3D model of the knee CT data, we compared and validated segmentation algorithms based on both objective comparisons and finite element (FE) analysis. For comparison purposes, we used 1 model reconstructed in accordance with the instructions of a clinical professional and 3 models reconstructed using image processing algorithms (Sobel operator, Laplacian of Gaussian operator, and Canny edge detection). Comparison was performed by inspecting intermodel morphological deviations with the iterative closest point (ICP) algorithm, and FE analysis was performed to examine the effects of the segmentation algorithm on the results of the knee joint movement analysis. PMID:25538950

  14. Computed tomographic image analysis based on FEM performance comparison of segmentation on knee joint reconstruction.

    PubMed

    Jang, Seong-Wook; Seo, Young-Jin; Yoo, Yon-Sik; Kim, Yoon Sang

    2014-01-01

    The demand for an accurate and accessible image segmentation to generate 3D models from CT scan data has been increasing as such models are required in many areas of orthopedics. In this paper, to find the optimal image segmentation to create a 3D model of the knee CT data, we compared and validated segmentation algorithms based on both objective comparisons and finite element (FE) analysis. For comparison purposes, we used 1 model reconstructed in accordance with the instructions of a clinical professional and 3 models reconstructed using image processing algorithms (Sobel operator, Laplacian of Gaussian operator, and Canny edge detection). Comparison was performed by inspecting intermodel morphological deviations with the iterative closest point (ICP) algorithm, and FE analysis was performed to examine the effects of the segmentation algorithm on the results of the knee joint movement analysis. PMID:25538950

  15. On-Site Geologic Core Analysis Using a Portable X-ray ComputedTomographic System

    SciTech Connect

    Freifeld, Barry M.; Kneafsey, Timothy J.; Rack, Frank

    2004-03-01

    X-ray computed tomography (CT) is an established techniquefor nondestructively characterizing geologic cores. CT providesinformation on sediment structure, diagenetic alteration, fractures, flowchannels and barriers, porosity, and fluid-phase saturation. A portableCT imaging system has been developed specifically for imaging whole-roundcores at the drilling site. The new system relies upon carefully designedradiological shielding to minimize the size and weight of the resultinginstrument. Specialized x-ray beam collimators and filters maximizesystem sensitivity and performance. The system has been successfullydeployed on the research vessel Joides Resolution for Ocean DrillingProgram's Leg 204 and 210, within the Ocean Drilling Program'srefrigerated Gulf Coast Core Repository, as well as on the Hot Ice #1drilling platform located near the Kuparuk Field, Alaska. A methodologyfor performingsimple densiometry measurements, as well as scanning forgross structural features, will be presented using radiographs from ODPLeg 204. Reconstructed CT images from Hot Ice #1 will demonstrate the useof CT for discerning core textural features. To demonstrate the use of CTto quantitatively interpret dynamic processes, we calculate 95 percentconfidence intervals for density changes occurring during a laboratorymethane hydrate dissociation experiment. The field deployment of a CTrepresents a paradigm shift in core characterization, opening up thepossibility for rapid systematic characterization of three-dimensionalstructural features and leading to improved subsampling andcore-processing procedures.

  16. Jugular foramen: anatomic and computed tomographic study

    SciTech Connect

    Daniels, D.L.; Williams, A.L.; Haughton, V.M.

    1984-01-01

    The computed tomographic (CT) appearance of the jugular foramen was examined in detail, and anatomic and CT sections were correlated. The pars nervosa and pars vascularis were identified, and, with intravenous contrast enhancement, a rapid sequence of scans at a gantry angle of +30/sup 0/ to the canthomeatal line demonstrated cranial nerves IX, X, and XI. The osseous margins of the jugular foramen were best shown by CT at planes of sections parallel and positive (0/sup 0/-30/sup 0/) to the canthomeatal line. CT can be used to evaluate osseous anatomy and the jugular foramen with precision sufficient to confidently exclude an intracanalicular mass.

  17. Health risks from computed tomographic screening.

    PubMed

    Krantz, Seth B; Meyers, Bryan F

    2015-05-01

    Results of the recent National Lung Cancer Screening Trial show a significant survival benefit for annual screening with a low-dose computed tomographic (CT) scan in high-risk individuals. This result has led the US Preventive Services Task Force to recommend annual low-dose CT scans for this at-risk population. Less well characterized are the risks from screening. The primary risks from screening are radiation exposure, false-positive results and unnecessary diagnostic and therapeutic procedures, overdiagnosis and overtreatment, and increased psychological distress. This article reviews these risks, which must be considered and weighed against the benefits when discussing enrollment with patients. PMID:25901559

  18. Computed tomographic features of canine nonparenchymal hemangiosarcoma.

    PubMed

    Fukuda, Shoko; Kobayashi, Tetsuya; Robertson, Ian D; Oshima, Fukiko; Fukazawa, Eri; Nakano, Yuko; Ono, Shin; Thrall, Donald E

    2014-01-01

    The purpose of this retrospective study was to describe pre- and postcontrast computed tomographic (CT) characteristics of confirmed nonparenchymal hemangiosarcoma in a group of dogs. Medical records were searched during the period of July 2003 and October 2011 and dogs with histologically confirmed nonparenchymal hemangiosarcoma and pre- and postcontrast CT images were recruited. Two observers recorded a consensus opinion for the following CT characteristics for each dog: largest transverse tumor diameter, number of masses, general tumor shape, character of the tumor margin, precontrast appearance, presence of dystrophic calcification, presence of postcontrast enhancement, pattern of postcontrast enhancement, presence of regional lymphadenopathy, and presence of associated cavitary fluid. A total of 17 dogs met inclusion criteria. Tumors were located in the nasal cavity, muscle, mandible, mesentery, subcutaneous tissue, and retroperitoneal space. Computed tomographic features of nonparenchymal hemangiosarcoma were similar to those of other soft tissue sarcomas, with most tumors being heterogeneous in precontrast images, invasive into adjacent tissue, and heterogeneously contrast enhancing. One unexpected finding was the presence of intense foci of contrast enhancement in 13 of the 17 tumors (76%). This appearance, which is not typical of other soft tissue sarcomas, was consistent with contrast medium residing in vascular channels. Findings indicated that there were no unique distinguishing CT characteristics for nonparenchymal hemangiosarcoma in dogs; however, the presence of highly attenuating foci of contrast enhancement may warrant further investigation in prospective diagnostic sensitivity and treatment outcome studies. PMID:24382330

  19. Computed tomographic features of primary brain lymphoma.

    PubMed

    Barsky, M F; Coates, R K; Macdonald, D R

    1989-04-01

    Head computed tomographic (CT) examinations of 14 patients with primary brain lymphoma were reviewed to assess the CT features of the presenting and subsequent lesions. Presenting lesions were single in 62% and multiple in 38%. Lesions tended to be iso- or hyperdense and homogeneously enhancing. They were commonly located in the deep hemispheric regions, corpus callosum, and posterior fossa. Despite these characteristic patterns, the diagnosis of lymphoma was initially considered in just three patients. Follow-up CT showed good initial response to radiotherapy in 10 patients although mortality was high and posttherapy changes were frequent. Consideration of primary brain lymphoma by radiologists is important, as needle biopsy and radiotherapy may be preferred to a surgical resection. PMID:2702505

  20. Neck after vertical hemilaryngectomy: computed tomographic study

    SciTech Connect

    DiSantis, D.J.; Balfe, D.M.; Hayden, R.; Sessions, D.; Sagel, S.S.

    1984-06-01

    Computed tomographic scans in 22 postoperative vertical hemilaryngectomy patients were analyzed retrospectively to determine the normal postoperative appearance and to evaluate the role of CT in assessing recurrent neoplasm. Twelve patients without clinical evidence of recurrence illustrated the normal postoperative changes. In the six patients with recurrent neoplasm, the CT manifestations included increased width of the remaining true vocal cord, convexity of the surgically formed pseudocord at glottic level, subglottic tumor, and extralaryngeal neck masses. Recurrence was mimicked in four patients by bulky soft tissue at the endolaryngeal operative site at both CT and laryngoscopy. CT supplemented the physical examination and indirect laryngoscopy, providing information regarding the presence and extent of tumor that was useful in planning the mode or scope of subsequent therapy.

  1. Computed tomographic recognition of gastric varices

    SciTech Connect

    Balthazar, E.J.; Megibow, A.; Naidich, D.; LeFleur, R.S.

    1984-06-01

    The computed tomographic (CT) findings in 13 consecutive patients with proven gastric varices were analyzed and correlated with the radiographic, angiographic, and gastroscopic evaluations. In 11 patients, CT clearly identified large (five) or smaller (six) varices located mainly along the posteromedial wall of the gastric fundus and proximal body of the stomach. Well defined rounded or tubular densities that enhanced during intravenous administration of contrast material and could not be distinguished from the gastric wall were identified. Dense, enhancing, round or tubular, intraluminal filling defects were seen in the cases where the stomach was distended with water. In seven patients, the CT examination correctly diagnosed the pathogenesis of gastric varices by identifying hepatic cirrhosis, calcific pancreatis, and carcinoma of the pancreas.

  2. Computed tomographic anatomy of the equine foot.

    PubMed

    Claerhoudt, S; Bergman, E H J; Saunders, J H

    2014-10-01

    This study describes a detailed computed tomographic reference of the normal equine foot. Ten forefeet of five adult cadavers, without evidence of orthopaedic disease, were used. Computed tomography (CT) was performed on all feet. Two-millimetre thick transverse slices were obtained, and sagittal and dorsal planes were reformatted. The CT images were matched with the corresponding anatomic slices. The phalanges and the distal sesamoid bone showed excellent detail. The extensor and flexor tendons (including their attachments) could be clearly evaluated. The collateral (sesamoidean) ligaments could be readily located, but were difficult to delineate at their proximal attachment. The distal digital annular ligament could only be distinguished from the deep digital flexor tendon proximal to the distal sesamoid bone, and its proximal attachment could be identified, but not its distal insertion. Small ligaments (impar ligament, chondrosesamoidean, chondrocoronal and chondrocompedal ligaments, axial and abaxial palmar ligaments of the proximal inter-phalangeal joint) were seen with difficulty and not at all slices. The joint capsules could not be delineated from the surrounding soft tissue structures. The lateral and medial proprius palmar digital artery and vein could be visualized occasionally on some slices. The ungular cartilages, corium and hoof wall layering were seen. The nerves, the articular and fibrocartilage of the distal sesamoid bone and the chondroungular ligament could not be assessed. Computed tomography of the equine foot can be of great value when results of radiography and ultrasonography are inconclusive. Images obtained in this study may serve as reference for CT of the equine foot. PMID:24611958

  3. Comparative analysis of fluorescent angiography, computed tomographic angiography and magnetic resonance angiography for planning autologous breast reconstruction

    PubMed Central

    Chae, Michael P.; Hunter-Smith, David J.

    2015-01-01

    Background The high incidence of breast cancer and growing number of breast cancer patients undergoing mastectomy has led to breast reconstruction becoming an important part of holistic treatment for these patients. In planning autologous reconstructions, preoperative assessment of donor site microvascular anatomy with advanced imaging modalities has assisted in the appropriate selection of flap donor site, individual perforators, and lead to an overall improvement in flap outcomes. In this review, we compare the accuracy of fluorescent angiography, computed tomographic angiography (CTA), and magnetic resonance angiography (MRA) and their impact on clinical outcomes. Methods A review of the published English literature dating from 1950 to 2015 using databases, such as PubMed, Medline, Web of Science, and EMBASE was undertaken. Results Fluorescent angiography is technically limited by its inability to evaluate deep-lying perforators and hence, it has a minimal role in the preoperative setting. However, it may be useful intraoperatively in evaluating microvascular anastomotic patency and the mastectomy skin perfusion. CTA is currently widely considered the standard, due to its high accuracy and reliability. Multiple studies have demonstrated its ability to improve clinical outcomes, such as operative length and flap complications. However, concerns surrounding exposure to radiation and nephrotoxic contrast agents exist. MRA has been explored, however despite recent advances, the image quality of MRA is considered inferior to CTA. Conclusions Preoperative imaging is an essential component in planning autologous breast reconstruction. Fluorescent angiography presents minimal role as a preoperative imaging modality, but may be a useful intraoperative adjunct to assess the anastomosis and the mastectomy skin perfusion. Currently, CTA is the gold standard preoperatively. MRA has a role, particularly for women of younger age, iodine allergy, and renal impairment. PMID

  4. Computed tomographic findings in orbital Mucor

    SciTech Connect

    Greenberg, M.R.; Lippman, S.M.; Grinnell, V.S.; Colman, M.F.; Edwards, J.E. Jr.

    1985-07-01

    Mucormycosis is an increasingly important infection in immunocompromised patients; knowledge regarding the variability of its clinical manifestations is expanding steadily. The infection is of paranasal sinus origin and may involve the orbit secondarily via freely communicating foramina and venous channels. Death often ensues when the infection spreads either into the cavernous sinus or the central nervous system. Early diagnosis of rhinocerebral mucormycosis is crucial for a successful outcome. Computed tomographic (CT) scanning is used to visualize many intraorbital pathologic abnormalities. The patient discussed in this paper had extensive orbital Mucor that appeared minimal on a CT scan. This inability of the scan to reflect the severity of infection prompted a review of the literature describing the use of CT scans for detecting this potentially fatal, opportunistic infection. The search showed that a disparity between scan findings and the severity of the disease is the rule rather than the exception. Recognition of this disparity has significant implications for appropriate diagnosis and management of orbital Mucor.

  5. A computed tomographic study of schizophrenia.

    PubMed

    Siddharatha; Lal, N; Tewari, S C; Dalal, P K; Kohli, N; Srivastava, S

    1997-04-01

    Fifty schizophrenic patients fulfilling DSM-III-R criteria, and group matched normal healthy controls were selected for the study The case and control groups have been compared in terms of VBR, WSF and WTF. In the study schizophrenics have been divided into positive, negative and mixed subgroups on basis of SAPS and SANS, and these subgroups are compared with each other for VBR, WSF & WTF. Tomographic abnormalities were noted in schizophrenics, particularly with negative and mixed subtypes, when compared to controls. PMID:21584057

  6. The computed tomographic findings of peritentorial subdural hemorrhage

    SciTech Connect

    Lau, L.S.; Pike, J.W.

    1983-03-01

    The computed tomographic (CT) findings in six cases of subdural hemorrhage in the peritentorial region are listed and discussed. The CT appearance of peritentorial subdural hemorrhage sometimes mimicks that of intra-axial lesions, but coronal scanning or reconstruction can be used to resolve this problem. Awareness of this unusual location for subdural hemorrhage is helpful in providing an accurate preoperative diagnosis.

  7. Verifying X-Radiographs With Computed Tomographs

    NASA Technical Reports Server (NTRS)

    Roy, Jagatjit; Pascua, Antonio G.

    1991-01-01

    Nondestructive technique gives added confidence in inspection. Ambiguous indications in radiographic inspections of metal castings checked by computed tomography. Fast and inexpensive conventional x-ray inspection used to make film image of overall casting, and slower, more costly computed tomography used to reinspect relatively few parts of casting presenting possible diffraction patterns or other difficult-to-interpret features. Method effective in resolving ambiguities in radiographs of turbine blades. Provides same information as metallurgical sectioning.

  8. Computed tomographic findings in penetrating peptic ulcer

    SciTech Connect

    Madrazo, B.L.; Halpert, R.D.; Sandler, M.A.; Pearlberg, J.L.

    1984-12-01

    Four cases of peptic ulcer penetrating the head of the pancreas were diagnosed by computed tomography (CT). Findings common to 3 cases included (a) an ulcer crater, (b) a sinus tract, and (c) enlargement of the head of the pancreas. Unlike other modalities, the inherent spatial resolution of CT allows a convenient diagnosis of this important complication of peptic ulcer disease.

  9. Bilateral pulmonary sequestration: computed tomographic appearance

    SciTech Connect

    Wimbish, K.J.; Agha, F.P.; Brady, T.M.

    1983-04-01

    Intralobar pulmonary sequestration is one manifestation of the wide spectrum of congenital bronchopulmonary foregut malformations. Bilateral intralobar pulmonary sequestration is an exceedingly rare anomaly. Only two pathologically proven cases and one possible case have been reported. We report a case presenting as bilateral paraspinal masses, studied by computed tomograpy (CT) and angiography.

  10. Computed tomographic inspection of sample ampoule cartridge assemblies (SACA)

    SciTech Connect

    Krauss, D.G.

    1996-12-31

    This paper will describe and analyze the steps taken to provide Computed Tomographic (CT) inspection of Crystal Growth Furnace (CGF) Sample Ampoule Cartridge Assemblies (SACA). These cartridges were aboard STS-73 during its micro gravity laboratory (USML-2) flight in September 1995. Available radiation sources included a Seifert 420 kilovoltage constant potential dual focal spot X-Ray system and a Gamma Industries Cobalt{sup 60} radioactive isotope camera currently containing 35 curies of source strength.

  11. Dynamic computed tomographic scans in experimental brain abscess.

    PubMed

    Enzmann, D R; Placone, R C; Britt, R H

    1984-01-01

    Dynamic computed tomographic scans were performed in an experimental brain abscess model to establish criteria that could be utilized in abscess staging. The vascular phase of the time-density curves did not differentiate cerebritis and capsule stages. The amount of residual enhancement after the first pass of an intra-arterial contrast bolus differed between major abscess stages, the greater residual enhancement being noted in the capsule stage. PMID:6462439

  12. Computed tomographic findings in 15 dogs with eosinophilic bronchopneumopathy.

    PubMed

    Mesquita, Luis; Lam, Richard; Lamb, Christopher R; McConnell, J Fraser

    2015-01-01

    Eosinophilic bronchopneumopathy is a disease characterized by the infiltration of the lung and bronchial mucosa by eosinophils. The aim of the present study was to describe the CT findings in a large series of dogs with confirmed diagnosis of eosinophilic bronchopneumopathy. Computed tomographic scans of 15 dogs with confirmed diagnosis of eosinophilic bronchopneumopathy were evaluated retrospectively by two boarded radiologists who reached a consensus. Abnormalities were identified in 14/15 (93%) dogs, including pulmonary parenchymal abnormalities in 14/15 (93%) dogs, bronchial wall thickening in 13 (87%) dogs, which was considered marked in eight (53%), plugging of the bronchial lumen by mucus/debris in 11 (73%) dogs, and bronchiectasis in nine (60%) dogs. Pulmonary nodules were identified in 5/15 (33%) dogs including one dog with a mass. All dogs with a nodular lung pattern had additional abnormalities. Lymphadenopathy was present in 10 dogs (67%). Lesions associated with eosinophilic bronchopneumopathy are variable and heterogeneous and encompass a wider variety of computed tomographic features than reported previously. Computed tomographic images were abnormal in the majority of affected dogs, hence CT is a useful modality to characterize the nature and distribution of thoracic lesions in dogs with eosinophilic bronchopneumopathy. PMID:25124052

  13. Clinical and computed tomographic predictors of chronic bronchitis in COPD: a cross sectional analysis of the COPDGene study

    PubMed Central

    2014-01-01

    Background Chronic bronchitis (CB) has been related to poor outcomes in Chronic Obstructive Pulmonary Disease (COPD). From a clinical standpoint, we have shown that subjects with CB in a group with moderate to severe airflow obstruction were younger, more likely to be current smokers, male, Caucasian, had worse health related quality of life, more dyspnea, and increased exacerbation history compared to those without CB. We sought to further refine our clinical characterization of chronic bronchitics in a larger cohort and analyze the CT correlates of CB in COPD subjects. We hypothesized that COPD patients with CB would have thicker airways and a greater history of smoking, acute bronchitis, allergic rhinitis, and occupational exposures compared to those without CB. Methods We divided 2703 GOLD 1–4 subjects in the Genetic Epidemiology of COPD (COPDGene®) Study into two groups based on symptoms: chronic bronchitis (CB+, n = 663, 24.5%) and no chronic bronchitis (CB-, n = 2040, 75.5%). Subjects underwent extensive clinical characterization, and quantitative CT analysis to calculate mean wall area percent (WA%) of 6 segmental airways was performed using VIDA PW2 (http://www.vidadiagnostics.com). Square roots of the wall areas of bronchi with internal perimeters 10 mm and 15 mm (Pi10 and Pi15, respectively), % emphysema, %gas trapping, were calculated using 3D Slicer (http://www.slicer.org). Results There were no differences in % emphysema (11.4 ± 12.0 vs. 12.0 ± 12.6%, p = 0.347) or % gas trapping (35.3 ± 21.2 vs. 36.3 ± 20.6%, p = 0.272) between groups. Mean segmental WA% (63.0 ± 3.2 vs. 62.0 ± 3.1%, p < 0.0001), Pi10 (3.72 ± 0.15 vs. 3.69 ± 0.14 mm, p < 0.0001), and Pi15 (5.24 ± 0.22 vs. 5.17 ± 0.20, p < 0.0001) were greater in the CB + group. Greater percentages of gastroesophageal reflux, allergic rhinitis, histories of asthma and acute bronchitis, exposures to dusts and

  14. Computed tomographic evaluation of pineal calcification.

    PubMed

    Kohli, N; Rastogi, H; Bhadury, S; Tandon, V K

    1992-04-01

    A prospective study to ascertain the incidence of normally calcified pineal gland, was carried out in 1000 consecutive patients from different parts of Uttar Pradesh (India), undergoing cranial computed tomography for reasons other than a pineal or parapineal pathology. A total of 167 (16.70%) patients were found to have calcified pineals. Of these 128 were males and 39 females. The incidence rose from 1.16 per cent in the first decade to 31.88 per cent above the age of 50 yr. The percentage incidence of normal pineal calcification was lower than that seen in the Western population. No significant difference was found between men and women in any age group. Although calcification appeared as early as the first decade, this percentage was significantly lower than in the higher age groups. Significantly higher incidence rates were seen in the second decade, third decade and sixth decade onwards. PMID:1428055

  15. Lymphadenopathy in celiac disease: computed tomographic observations

    SciTech Connect

    Jones, B.; Bayless, T.M.; Fishman, E.K.; Siegelman, S.S.

    1984-06-01

    Lymphadenopathy in patients with celiac disease is generally viewed with alarm due to the association between celiac disease and intestinal lymphoma. Four patients with celiac disease are described in whom significant mesenteric and paraaortic adenopathy was demonstrated by computed tomogrophy (CT). The subsequent clinical course of these patients revealed no evidence of lymphoma. In two patients with longstanding celiac disease and recent relapse, exploratory laparotomy revealed reactive hyperplasia in the enlarged glands; in one patient this was associated with intestinal ulceration, and in the other no underlying pathology was found. Follow-up CT scans in both these patients demonstrated regression of the findings with clinical improvement. In the other two patients, CT was performed as part of the initial evaluation.

  16. A computed tomographic imaging system for experimentation

    NASA Astrophysics Data System (ADS)

    Lu, Yanping; Wang, Jue; Liu, Fenglin; Yu, Honglin

    2008-03-01

    Computed tomography (CT) is a non-invasive imaging technique, which is widely applied in medicine for diagnosis and surgical planning, and in industry for non-destructive testing (NDT) and non-destructive evaluation (NDE). So, it is significant for college students to understand the fundamental of CT. In this work, A CT imaging system named CD-50BG with 50mm field-of-view has been developed for experimental teaching at colleges. With the translate-rotate scanning mode, the system makes use of a 7.4×10 8Bq (20mCi) activity 137Cs radioactive source which is held in a tungsten alloy to shield the radiation and guarantee no harm to human body, and a single plastic scintillator + photomultitude detector which is convenient for counting because of its short-time brightness and good single pulse. At same time, an image processing software with the functions of reconstruction, image processing and 3D visualization has also been developed to process the 16 bits acquired data. The reconstruction time for a 128×128 image is less than 0.1 second. High quality images with 0.8mm spatial resolution and 2% contrast sensitivity can be obtained. So far in China, more than ten institutions of higher education, including Tsinghua University and Peking University, have already applied the system for elementary teaching.

  17. Characteristics of high-risk coronary plaques identified by computed tomographic angiography and associated prognosis: a systematic review and meta-analysis.

    PubMed

    Thomsen, Camilla; Abdulla, Jawdat

    2016-02-01

    To clarify the potential role of coronary computed tomographic angiography (CCTA) in characterizing and prognosticating high-risk coronary plaques. A systematic review and meta-analysis were conducted to compare high-risk vs. low-risk plaques and culprit vs. non-culprit lesions in patients with acute coronary syndrome (ACS) vs. stable angina (SA). High-risk plaques were defined by at least one of the following features: non-calcified plaque (NCP), the presence of spotty calcified plaque (SCP), or increased remodelling index (RI). Results of included studies were pooled as odds ratios (OR) or weighted mean differences (WMD) with 95% confidence interval (CI). Eighteen eligible studies provided data to compare plaque types, plaque volume, and RI. Six studies provided data on ACS events in vulnerable high-risk vs. low-risk calcified plaques after 35 ± 2 months of follow-up. ACS patients had significantly higher number of NCP and SCP compared with SA patients with OR = 1.96 (1.47-2.60; 95% CI) P = 0.0001 and OR = 4.5 (2.98-6.83; 95% CI) P = 0.0001, respectively. Total plaque volume in ACS was not larger than SA: WMD = 22.9 (-22.1 to 67; 95% CI) mm(3), P = 0.32, but NCP volume was significantly larger: WMD = 28.8 (10.9-46.7; 95% CI) mm(3), P = 0.002. RI was higher in culprit lesions in ACS compared with SA and compared with non-culprit lesions in ACS patients: WMD = 0.48 (0.25-0.70; 95% CI) P = 0.0001 and 0.19 (0.07-0.30) P = 0.0001, respectively. The associated risk of future ACS was significantly higher in high-risk than in low-risk plaques: OR = 12.1 (5.24-28.1; 95% CI) P = 0.0001. CCTA can non-invasively characterize high-risk vulnerable coronary plaques and can predict future ACS events in patients with high-risk plaques. PMID:26690951

  18. Pineal region tumors: computed tomographic-pathologic spectrum

    SciTech Connect

    Futrell, N.N.; Osborn, A.G.; Cheson. B.D.

    1981-11-01

    While several computed tomographic (CT) studies of posterior third ventricular neoplasms have included descriptions of pineal tumors, few reports have concentrated on these uncommon lesions. Some authors have asserted that the CT appearance of many pineal tumors is virtually pathognomonic. A series of nine biopsy-proved pineal gland and eight other presumed tumors is presented that illustrates their remarkable heterogeneity in both histopathologic and CT appearance. These tumors included germinomas, teratocarcinomas, hamartomas, and other varieties. They had variable margination, attentuation, calcification, and suprasellar extension. Germinomas have the best response to radiation therapy. Biopsy of pineal region tumors is now feasible and is recommended for treatment planning.

  19. Computed tomographic spectrum of intracranial mycosis: correlation with histopathology

    SciTech Connect

    Whelan, M.A.; Stern, J.; deNapoli, R.A.

    1981-12-01

    Four cases of intracerebral fungal infection are reviewed. The clinical course is outlined, and the computed tomographic (CT) characteristics are analyzed in light of known pathological data. The CT appearance of intracranial mycosis is dependent on the type of fungus as well as the dominant infecting form, i.e., yeast or hyphae. The hyphal form leads predominantly to a CT pattern consistent with vascular occlusion and secondary abscess formation; the yeast form generally results in noncaseating granulomas, which appear on CT scan as nodular enhancing lesions. If the patient survives the acute infective process, these fungal lesions undergo a prolonged subacute phase, and may eventually calcify.

  20. The UF series of tomographic computational phantoms of pediatric patients

    SciTech Connect

    Lee, Choonik; Williams, Jonathan L.; Lee, Choonsik; Bolch, Wesley E.

    2005-12-15

    Two classes of anthropomorphic computational phantoms exist for use in Monte Carlo radiation transport simulations: tomographic voxel phantoms based upon three-dimensional (3D) medical images, and stylized mathematical phantoms based upon 3D surface equations for internal organ definition. Tomographic phantoms have shown distinct advantages over the stylized phantoms regarding their similarity to real human anatomy. However, while a number of adult tomographic phantoms have been developed since the early 1990s, very few pediatric tomographic phantoms are presently available to support dosimetry in pediatric diagnostic and therapy examinations. As part of a larger effort to construct a series of tomographic phantoms of pediatric patients, five phantoms of different ages (9-month male, 4-year female, 8-year female, 11-year male, and 14-year male) have been constructed from computed tomography (CT) image data of live patients using an IDL-based image segmentation tool. Lungs, bones, and adipose tissue were automatically segmented through use of window leveling of the original CT numbers. Additional organs were segmented either semiautomatically or manually with the aid of both anatomical knowledge and available image-processing techniques. Layers of skin were created by adding voxels along the exterior contour of the bodies. The phantoms were created from fused images taken from head and chest-abdomen-pelvis CT exams of the same individuals (9-month and 4-year phantoms) or of two different individuals of the same sex and similar age (8-year, 11-year, and 14-year phantoms). For each model, the resolution and slice positions of the image sets were adjusted based upon their anatomical coverage and then fused to a single head-torso image set. The resolutions of the phantoms for the 9-month, 4-year, 8-year, 11-year, and 14-year are 0.43x0.43x3.0 mm, 0.45x0.45x5.0 mm, 0.58x0.58x6.0 mm, 0.47x0.47x6.00 mm, and 0.625x0.625x6.0 mm, respectively. While organ masses can be

  1. Computed tomographic features of fibrous dysplasia of maxillofacial region

    PubMed Central

    Karjodkar, Freny R; Umarji, Hemant R

    2011-01-01

    Purpose This study was to find the computed tomographic features of fibrous dysplasia of the maxillofacial region. Materials and Methods All eight cases included in the study reported either to Government Dental College and Hospital or Nair Hospital Dental College, Mumbai between 2003 and 2009. The patients were prescribed computed tomogram in addition to conventional radiographs of maxillofacial region which were studied for characteristic features of fibrous dysplasia. The diagnosis of fibrous dysplasia was confirmed by histopathological report. Results All cases showed the ill-defined margins of lesions except in the region where the lesions were extending to cortex of the involved bone. Internal structure of all cases showed ground glass appearance. Four cases of maxillary lesion showed the displacement of maxillary sinus maintaining the shape of maxillary sinus. Two cases showed complete obliteration of maxillary sinus. Displacement of inferior alveolar canal did not follow any typical pattern in any of the cases but was displaced in different directions. Conclusion The craniofacial type of fibrous dysplasia is as common as fibrous dysplasia of jaw. The margins, extent, internal structure and effect on surrounding structure are well detected on computed tomographic images. PMID:21977470

  2. Predictors of Incomplete Optical Colonoscopy Using Computed Tomographic Colonography

    PubMed Central

    Sachdeva, Reetika; Tsai, Salina D.; El Zein, Mohamad H.; Tieu, Alan A.; Abdelgelil, Ahmed; Besharati, Sepideh; Khashab, Mouen A.; Kalloo, Anthony N.; Kumbhari, Vivek

    2016-01-01

    Background/Aims: Optical colonoscopy (OC) is the primary modality for investigation of colonic pathology. Although there is data on demographic factors for incomplete OC, paucity of data exists for anatomic variables that are associated with an incomplete OC. These anatomic variables can be visualized using computed tomographic colonography (CTC). We aim to retrospectively identify variables associated with incomplete OC using CTC and develop a scoring method to predict the outcome of OC. Patients and Methods: In this case–control study, 70 cases (with incomplete OC) and 70 controls (with complete OC) were identified. CTC images of cases and controls were independently reviewed by a single CTC radiologist. Demographic and anatomical parameters were recorded. Data was examined using descriptive linear statistics and multivariate logistic regression model. Results: On analysis, female gender (80% vs 58.6% P = 0.007), prior abdominal/pelvic surgeries (51.4% vs 14.3% P < 0.001), colonic length (187.6 ± 30.0 cm vs 163.8 ± 27.2 cm P < 0.001), and number of flexures (11.4 ± 3.1 vs 8.4 ± 2.9 P < 0.001) increased the risk for incomplete OC. No significant association was observed for increasing age (P = 0.881) and history of severe diverticulosis (P = 0.867) with incomplete OC. A scoring system to predict the outcome of OC is proposed based on CTC findings. Conclusion: Female gender, prior surgery, and increasing colonic length and tortuosity were associated with incomplete OC, whereas increasing age and history of severe diverticulosis were not. These factors may be used in the future to predict those patients who are at risk of incomplete OC. PMID:26831606

  3. Cystic tumors of the fetal and neonatal cerebrum: ultrasound and computed tomographic evaluation

    SciTech Connect

    Sauerbrei, E.E.; Cooperberg, P.L.

    1983-06-01

    Three patients (two infants and one fetus) had complex (partially cystic and partially solid) supratentorial tumors involving the brain. The sonographic and computed tomographic appearance in each of these lesions is described and discussed. The cystic component of each lesion was equally well delineated by the two modalities, whereas the peripheral solid component was better defined by contrast-enhanced computed tomographic scans.

  4. Computed tomographic evaluation of gallstone calcification for biliary lithotripsy.

    PubMed

    Caslowitz, P L; Fishman, E K; Kafonek, D R; Lillemoe, K D; Mitchell, S; Widlus, D M; Saba, G P

    1991-04-01

    As the Food and Drug Administration trials for biliary lithotripsy in the United States near completion, future criteria for patient eligibility remain to be defined. Gallstone calcification greater than 3-mm partial rim on plain film (KUB) or oral cholecystogram (OCG) has excluded patients thus far, since early results of gallstone clearance (lithotripsy plus chemodissolution) were suboptimal with calcified stones. To evaluate the usefulness of these criteria for gallstone fragmentation, computed tomographic (CT) scans were performed on 20 patients immediately prior to lithotripsy to evaluate gallstone density and 24 hours after lithotripsy to observe the CT appearance of fragmentation. The adequacy of fragmentation was determined by pre- and post-lithotripsy sonography. This report constitutes the results of these investigations. PMID:10149158

  5. Is computed tomographic colonography being held to a higher standard?

    PubMed

    Garg, Samita; Ahnen, Dennis J

    2010-02-01

    Recent guidelines for colorectal cancer screening have reached different conclusions on whether computed tomographic colonography (CTC) is an acceptable screening option, and the Centers for Medicare & Medicaid Services recently decided not to cover CTC screening. The rationale against recommending or covering CTC screening includes concerns about radiation exposure, false-negative rates for small polyps, the discovery of extracolonic findings, variability in performance, a lack of targeted studies, a higher adenoma rate in the Medicare-eligible age group, and an absence of evidence that covering CTC would increase overall screening rates. Similar concerns can be raised for other recommended and covered colon cancer screening tests, but it seems that CTC is being held to a new and higher standard. PMID:20124234

  6. Epinephrine-enhanced computed tomographic arthrography of the canine shoulder.

    PubMed

    De Rycke, Lieve; van Bree, Henri; Van Caelenberg, Annemie; Polis, Ingeborgh; Duchateau, Luc; Gielen, Ingrid

    2015-10-01

    The aim of this study was to investigate the effect of epinephrine-enhanced computed tomographic arthrography (CTA) on the image sharpness of the lateral and medial glenohumeral ligaments (LGHL and MGHL, respectively), biceps tendon (BT) and joint cartilage (JC) in the canine shoulder. The shoulders of eight normal dogs were examined using a 4-slice helical CT scanner. The right shoulders were injected with Iohexol and the left shoulders with a mixture of Iohexol and epinephrine. CTA images were obtained after 1, 3, 5, 9, 13, 20 and 30 min and the image sharpness of the intra-articular structures in both shoulders was graded for visibility. The attenuation values were measured to examine the persistence of contrast appearance. Admixture of epinephrine and Iohexol significantly improved the image sharpness of the LGHL and the BT, especially on delayed CTA images. The use of epinephrine did not negatively affect post-CTA recovery. PMID:26412512

  7. Central nervous system leukemia and lymphoma: computed tomographic manifestations

    SciTech Connect

    Pagani, J.J.; Libshitz, H.I.; Wallace, S.; Hayman, L.A.

    1981-12-01

    Computed tomographic (CT) abnormalities in the brain were identified in 31 of 405 patients with leukemia or lymphoma. Abnormalities included neoplastic masses (15), hemorrhage (nine), abscess (two), other brain tumors (four), and methotrexate leukoencephalopathy (one). CT was normal in 374 patients including 148 with meningeal disease diagnosed by cerebrospinal fluid cytologic examination. Prior to treatment, malignant masses were isodense or of greater density with varying amounts of edema. Increase in size or number of the masses indicated worsening. Response to radiation and chemotherapy was manifested by development of a central low density region with an enhancing rim. CT findings correlated with clinical and cerebrospinal fluid findings. The differential diagnosis of the various abnormalities is considered.

  8. Computed tomographic arthrography of the normal canine elbow.

    PubMed

    Gendler, Andrew; Keuler, Nicholas S; Schaefer, Susan L

    2015-01-01

    Comprehensive evaluation of canine elbow joint dysfunction includes assessment of articular cartilage, which can noninvasively be performed with contrast arthrography. Aims of this prospective study were to compare positive contrast computed tomographic (CT) arthrography and histomorphometry measures of cartilage thickness in normal canine elbows, and to determine the optimal contrast medium concentration. Thirty-two canine cadaver elbows were examined using multidetector CT, before and after intra-articular administration of iohexol at one of three different concentrations. Articular cartilage thickness was measured on both the CT arthrography images and corresponding histologic specimens. Mean difference (bias) between the CT arthrography and histomorphologic measurements was 0.18 and 0.19 mm in the sagittal and dorsal planes, respectively. Mean bias and precision of CT arthrography measurements made in the sagittal or dorsal reformations were not significantly different from one another. Computed tomographic arthrography measurements from elbows with 75 mg I/ml were significantly larger and had greater bias compared to other contrast medium groups (150 and 37.5 mg I/ml). There was no significant difference in CT arthrography measurement precision between different contrast medium concentrations. Histomorphologic thickness of the articular cartilage overlying the cranial aspect of the ulna (mean 0.32 mm) was significantly thinner than cartilage of the radius (0.36 mm) or humerus (0.36 mm). Findings from this cadaver study indicated that CT arthrography delineates articular cartilage of the normal canine elbow; yields cartilage thickness measures slightly greater than histomorphometry measures; and provides high measurement precision regardless of image plane, contrast medium concentration, or anatomic zone. PMID:25154869

  9. Pediatric computed tomographic angiography: imaging the cardiovascular system gently.

    PubMed

    Hellinger, Jeffrey C; Pena, Andres; Poon, Michael; Chan, Frandics P; Epelman, Monica

    2010-03-01

    Whether congenital or acquired, timely recognition and management of disease is imperative, as hemodynamic alterations in blood flow, tissue perfusion, and cellular oxygenation can have profound effects on organ function, growth and development, and quality of life for the pediatric patient. Ensuring safe computed tomographic angiography (CTA) practice and "gentle" pediatric imaging requires the cardiovascular imager to have sound understanding of CTA advantages, limitations, and appropriate indications as well as strong working knowledge of acquisition principles and image post processing. From this vantage point, CTA can be used as a useful adjunct along with the other modalities. This article presents a summary of dose reduction CTA methodologies along with techniques the authors have employed in clinical practice to achieve low-dose and ultralow-dose exposure in pediatric CTA. CTA technical principles are discussed with an emphasis on the low-dose methodologies and safe contrast medium delivery strategies. Recommended parameters for currently available multidetector-row computed tomography scanners are summarized alongside recommended radiation and contrast medium parameters. In the second part of the article an overview of pediatric CTA clinical applications is presented, illustrating low-dose and ultra-low dose techniques, with an emphasis on the specific protocols. PMID:20609882

  10. Computed tomographic appearances of the pelvis following hindquarter amputation.

    PubMed

    Fowler, J; Davies, A M; Carter, S R; Grimer, R J; Sneath, R S

    1992-12-01

    Bilateral and midline symmetry of the normal pelvic anatomy is an aid to the interpretation of computed tomographic (CT) examinations. Following hindquarter amputation (HQA) or partial hemipelvectomy (PHP) the normal anatomical relationships are disturbed. The CT examinations of 15 patients who had undergone either an HQA or a PHP for an advanced musculoskeletal malignancy are reviewed. The new "normal" anatomy revealed displacement of the bladder and small bowel to the side of surgery in one third of patients, more commonly in the PHP cases. There were varying degrees of wasting of the ipsilateral musculature, gluteus maximus muscle flap, erector spinae and psoas muscles, etc., because of partial denervation and disruption of their origin or insertion. Recurrent tumour was identified in eight of 10 cases in which it was clinically suspected prior to the CT examination. Invariably the recurrence arose within the muscle flap at the resection margin. Bone involvement by direct tumour spread was present in three cases. Pitfalls in differentiating recurrent tumour from scar tissue are discussed. PMID:1286416

  11. Computer-aided assessment of cardiac computed tomographic images

    NASA Astrophysics Data System (ADS)

    King, Martin; Giger, Maryellen; Suzuki, Kenji; Pan, Xiaochuan

    2007-03-01

    The accurate interpretation of cardiac CT images is commonly hindered by the presence of motion artifacts. Since motion artifacts commonly can obscure the presence of coronary lesions, physicians must spend much effort analyzing images at multiple cardiac phases in order to determine which coronary structures are assessable for potential lesions. In this study, an artificial neural network (ANN) classifier was designed to assign assessability indices to calcified plaques in individual region-of-interest (ROI) images reconstructed at multiple cardiac phases from two cardiac scans obtained at heart rates of 66 bpm and 90 bpm. Six individual features (volume, circularity, mean intensity, margin gradient, velocity, and acceleration) were used for analyzing images. Visually-assigned assessability indices were used as a continuous truth, and jack-knife analysis with four testing sets was used to evaluate the performance of the ANN classifier. In a study in which all six features were inputted into the ANN classifier, correlation coefficients of 0.962 +/- 0.006 and 0.935 +/- 0.023 between true and ANN-assigned assessability indices were obtained for databases corresponding to 66 bpm and 90 bpm, respectively.

  12. Computed tomographic epidurography: an aid to understanding deformation of the lumbar dural sac by epidural injections.

    PubMed

    Fukushige, T; Kano, T; Sano, T; Irie, M

    1999-09-01

    Local anaesthetics injected into the epidural space may deform the dural sac to a variable degree, thereby contributing to variability in the extent of the block. We investigated deformation of the lumbar dural sac after injection into the lumbar epidural space. The subjects were 26 patients with low-back pain who underwent lumbar epidurography and computed tomographic (CT) epidurography, of whom seven also underwent myelography and computed tomographic myelography. The epidural space was entered via the sacral hiatus in 24 patients and through the L5/S1 interspace in two patients. Ten millilitres of local anaesthetic was then injected into the epidural space followed by 20 mL of contrast medium. Computed tomographic epidurography was undertaken approximately 30-min after the epidural injection at the mid-vertebral and mid-discal levels from the first lumbar through to the first sacral vertebrae. The dural sac usually showed an oval or hexagonal shape on the transverse views at the first and second lumbar vertebral levels, and the shape of an inverted triangle below the level of the third lumbar vertebra. A median line of translucency was also observed on the posteroanterior epidurographic view in 25 of the 26 patients. This line was though to be a manifestation of the dural deformation to the inverted triangle. Dural sac deformation usually shows a specific pattern, although there are individual variations. Dural deformability is an important consideration in any analysis of the spread of epidural block or of the changes of epidural pressure after epidural injection of local anaesthetics. PMID:10549463

  13. A comparative evaluation of root canal area increase using three different nickel-titanium rotary systems: An ex vivo cone-beam computed tomographic analysis

    PubMed Central

    Deka, Adrija; Bhuyan, A.C.; Bhuyan, Darpana

    2015-01-01

    Background and Objectives: The present study was undertaken to compare and evaluate the area increase of root canals with ProTaper, iRaCe and Revo-S systems using cone beam computed tomography for analysis. Materials and Methodology: Forty five extracted human mandibular premolars having single canal and straight root were collected. Teeth were randomly assigned to three groups (n=15). Samples were decoronized by maintaining root length at 14 mm. Pre-instrumentation cone beam computed tomography scan was done after stabilizing the samples on wax blocks. The working length was determined at 1 mm short from the apical foramen by using a ISO 15 K-file tip protruding at apical foramen. Preparation was carried out according to the manufacturer's instructions. Finally, canals were instrumented upto 30/.06 apically for each group. After each instrumentation, root canals were irrigated with 2ml of 3% sodium hypochlorite solution followed by 2 ml of 17% EDTA solution. Final irrigation was done with 5ml of saline. Post instrumentation cone beam computed tomography scans of all samples in the 3 groups were acquired. Results: Mean percentage of area increase in different thirds of the canal was highest for ProTaper followed by i-RaCe and Revo-s system which was statistically significant. Interpretation and Conclusion: Root canal area increase was highest for ProTaper followed by i-Race and Revo-S systems. PMID:25684917

  14. The value of computed tomographic metrizamide myelography in the neuroradiological evaluation of the spine

    SciTech Connect

    Dublin, A.B.; McGahan, J.P.; Reid, M.H.

    1983-01-01

    The diagnostic value of plain film metrizamide myelopgraphy (PFMM) was compared with computed tomographic metrizamide myelography (CTMM) in a study of 106 individuals who had undergone high-resolution computed tomographic scanning of the spine. CTMM provided more significant information than PFMM in 42 of 106 cases (40%), but showed no advantage over PFMM in 63 of 106 cases (59%). In 19 of the 42 cases (45%), PFMM was useful in directing the CT analysis to the appropriate region of pathology. In one patient, PFMM revealed a mobile herniated disc that had not been visualized with CTMM. In 30 of 106 cases in which plain CT scans of the spine were also obtained, the addition of intrathecal metrizamide demonstrated additional pathology in ten individuals. In general, CTMM was useful in the delineation of a variety of pathologic entities, especially neoplasms and congenital abnormalities. Low-dose CTMM (3 ml of a 150 ml/mg concentration) was performed as an outpatient procedure and found to be a useful adjunct to plain CT in two patients. A schema for the radiological evaluation of pathology of the spine is presented.

  15. Computed Tomographic Findings of Syphilitic Aortitis: A Case Report

    SciTech Connect

    Kimura, Fumiko; Satoh, Hideyuki; Sakai, Fumikazu; Nishii, Noriko; Tohda, Joe; Fujimura, Mikihiko; Haruta, Shoji; Yamazaki, Kenji; Endo, Masahiro; Sakomura, Yasunari; Kurosama, Hiromi; Kasanuki, Hiroshi

    2004-03-15

    We describe the computerized tomographic (CT) findings of the aortic wall in a case of acute-phase syphilitic arteritis. The delayed phase of the contrast-enhanced CT shows a double-ring configuration of the thick thoracic aortic wall, which is similar to CT findings previously reported for Takayasu arteritis. We speculate that the resemblance of the CT findings for these two diseases accounts for their similar histopathological features.

  16. Tomographic Analysis of SRF Cavities as Asymmetric Plasma Reactors

    SciTech Connect

    M. Nikolić, A.L. Godunov, S. Popović, A. Samolov, J. Upadhyay, L. Vušković, H.L. Phillips, A-M. Valente-Feliciano

    2010-05-01

    The tomographic reconstruction of local plasma parameters for nonequilibrium plasma sources is a developing approach, which has a great potential in understanding the fundamental processes and phenomena during plasma processing of SRF cavity walls. Any type of SRF cavity presents a plasma rector with limited or distorted symmetry and possible presence of high gradients. Development of the tomographic method for SRF plasma analysis consists of several steps. First, we define the method based on the inversion of the Abel integral equation for a hollow spherical reactor. Second step is application of the method for the actual elliptical cavity shape. Third step consists of study of the effects of various shapes of the driven electrode. Final step consists of testing the observed line-integrated optical emission data. We will show the typical results in each step and the final result will be presented in the form of correlation between local plasma parameter distributions and local etching characteristics.

  17. Computer-Aided Tomographic Analysis of Interstitial Lung Disease (ILD) in Patients with Systemic Sclerosis (SSc). Correlation with Pulmonary Physiologic Tests and Patient-Centred Measures of Perceived Dyspnea and Functional Disability

    PubMed Central

    Salaffi, Fausto; Carotti, Marina; Di Donato, Eleonora; Di Carlo, Marco; Ceccarelli, Luca; Giuseppetti, Gianmarco

    2016-01-01

    ), patient-centred measures of perceived dyspnea and functional disability. Computer-aided tomographic analysis is computationally efficient, and in combination with physiologic and patient-centred measures, it could allow a means for accurately assessing and monitoring the disease progression or response to therapy. PMID:26930658

  18. Material characterization of dual-energy computed tomographic data using polar coordinates.

    PubMed

    Havla, Lukas; Peller, Michael; Cyran, Clemens; Nikolaou, Konstantin; Reiser, Maximilian; Dietrich, Olaf

    2015-01-01

    The purpose of this study was to evaluate a new dual-energy computed tomographic postprocessing approach on the basis of the transformation of dual-energy radiodensity data into polar coordinates. Given 2 corresponding dual-energy computed tomographic images, the attenuation data D(U1), D(U2) in Hounsfield units of both tube voltages (U1,U2) were transformed for each voxel to polar coordinates: r (distance to the radiodensity coordinate origin) is an approximate measure of electron density and φ (angle to the abscissa) differentiates between materials. PMID:25279847

  19. Three-Dimensional Computed Tomographic Analysis for Comminution of Pertrochanteric Femoral Fracture: Comminuted Anterior Cortex as a Predictor of Cutting Out

    PubMed Central

    Tsukada, Sachiyuki; Wakui, Motohiro; Yoshizawa, Hiroshi; Miyao, Masunao; Honma, Takeshi

    2016-01-01

    Background: Fixed angle sliding hip screw devices allow controlled impaction between the head neck fragment and the femoral shaft fragment in the surgical treatment of pertrochanteric fractures. This study was performed to evaluate the frequency and pattern of comminution at the fracture site, which may prevent the intended impaction. Materials and Methods: Three-dimensional computed tomography was used to investigate 101 pertrochanteric fractures treated with fixed angle sliding hip screw devices, with emphasis on the comminuted cortex. A comminuted fracture was defined as a fracture that had a third fracture fragment at the main fracture line. Results: There were 40 fractures without comminution and 61 with comminution. All 61 comminuted fractures had a comminuted posterior cortex, and 3 of 61 fractures also had comminution at the anterior cortex. The prevalence of cutting out of the implant from the femoral head was significantly higher in cases involving comminution at both the posterior and anterior cortices than in cases involving comminution only at the posterior cortex (66.7 % and 3.4 %, p < 0.0001). Conclusion: The posterior cortex was comminuted in 60.4% of pertrochanteric fractures and the anterior cortex in 3.0%. Intended impaction at the fracture site could not be obtained at any cortex in cases with comminution at both the anterior and posterior cortices; comminution at the anterior cortex may be a predictor of cutting out. PMID:27347234

  20. Cone beam computed tomographic analysis of maxillary premolars and molars to detect the relationship between periapical and marginal bone loss and mucosal thickness of maxillary sinus

    PubMed Central

    Sekerci, Ahmet-Ercan; Köse, Emre; Sisman, Yildiray

    2015-01-01

    Background This study assessed the relationship between mucosal thickness (MT) of the maxillary sinus and periodontal bone loss (PBL) and periapical condition of related teeth. We also aimed to identify the association between root apices and the inferior wall of the maxillary sinus using Cone beam computed tomography (CBCT). Material and Methods In this study, CBCT images of 205 patients with 410 maxillary sinuses were examined, retrospectively. A total of 582 maxillary molars and 587 premolars were observed. The relationship of each root with maxillary sinus and apical lesions of these roots were classified, PBL was examined and the situations of adjacent teeth were estimated. The effect of these conditions on sinus mucosal thickness (MT) was evaluated. Results There was a significant correlation between MT of maxillary sinus and both PBL and age (r = 0.52, p=0.000 and r = 0.111, p= 0.002, respectively). The frequency of MT increased as the severity of apical lesion enlarged. A positive correlation was found between MT and degree of PBL and periapical lesions. To reveal the association between MT and pulpoperiapical condition bivariate correlation was done and a significant relationship between the pulpoperiapical condition and MT was found (r = 0.17, p=0.000). Conclusions This retrospective study showed that MT of the maxillary sinus was common among patients with PBL and MT was significantly associated with PBL and apical lesions. The relationship of maxillary sinus to adjacent teeth had also positive correlation with MT. CBCT imaging enabled better evaluation of maxillary sinus, posterior teeth and surrounding structures compared to other imaging tools. Key words:Maxillary sinus mucosal thickness, apical periodontitis, periodontal bone loss, CBCT. PMID:26241459

  1. Efficient control schemes with limited computation complexity for Tomographic AO systems on VLTs and ELTs

    NASA Astrophysics Data System (ADS)

    Petit, C.; Le Louarn, M.; Fusco, T.; Madec, P.-Y.

    2011-09-01

    Various tomographic control solutions have been proposed during the last decades to ensure efficient or even optimal closed-loop correction to tomographic Adaptive Optics (AO) concepts such as Laser Tomographic AO (LTAO), Multi-Conjugate AO (MCAO). The optimal solution, based on Linear Quadratic Gaussian (LQG) approach, as well as suboptimal but efficient solutions such as Pseudo-Open Loop Control (POLC) require multiple Matrix Vector Multiplications (MVM). Disregarding their respective performance, these efficient control solutions thus exhibit strong increase of on-line complexity and their implementation may become difficult in demanding cases. Among them, two cases are of particular interest. First, the system Real-Time Computer architecture and implementation is derived from past or present solutions and does not support multiple MVM. This is the case of the AO Facility which RTC architecture is derived from the SPARTA platform and inherits its simple MVM architecture, which does not fit with LTAO control solutions for instance. Second, considering future systems such as Extremely Large Telescopes, the number of degrees of freedom is twenty to one hundred times bigger than present systems. In these conditions, tomographic control solutions can hardly be used in their standard form and optimized implementation shall be considered. Single MVM tomographic control solutions represent a potential solution, and straightforward solutions such as Virtual Deformable Mirrors have been already proposed for LTAO but with tuning issues. We investigate in this paper the possibility to derive from tomographic control solutions, such as POLC or LQG, simplified control solutions ensuring simple MVM architecture and that could be thus implemented on nowadays systems or future complex systems. We theoretically derive various solutions and analyze their respective performance on various systems thanks to numerical simulation. We discuss the optimization of their performance and

  2. Pedicular and Extrapedicular Morphometric Analysis in the Korean Population : Computed Tomographic Assessment Relevance to Pedicle and Extrapedicle Screw Fixation in the Thoracic Spine

    PubMed Central

    Kim, Jun-Hak; Choi, Gyeong-Mi; Chang, In-Bok; Ahn, Sung-Ki; Song, Joon-Ho

    2009-01-01

    Objective To evaluate the anatomical parameters that must be considered when performing thoracic transpedicular or extrapedicular screw fixation. Methods We selected 958 vertebrae (1,916 pedicles) from 98 patients for analysis. Eight parameters were measured from CT scans : the transverse outer pedicular diameter, transverse inner pedicular diameter, length, angle, chord length of the pedicles and the transverse width, angle, and chord length of the pedicle-rib units. Results The age of the patients ranged from 21 to 82 years (mean : 48.2 years) and there were 57 men and 41 women. The narrowest transverse outer pedicular diameter was at T5 (4.4 mm). The narrowest pedicle length was at T1 (15.9 mm). For pedicle angle, T1 was 31.6 degrees, which was the most convergent angle, and it showed the tendency of the lower the level, the lesser the convergent angle. The chord length showed a horizontal pattern with similar values at all levels. For the PRU width, T5 showed a similar pattern to the pedicle width at 13.4 mm. For the PRU angle, T1 was the largest angle at 46.2 degrees and the tendency was the lower the level, the narrower the angle. For chord length, T1 was the shortest at 46.9 mm and T8 was the longest at 60.1 mm. Conclusion When transpedicular screw fixations carried out at the mid-thoracic level, special care must be taken because there is a high chance of danger of medial wall violation. In these circumstances, extrapedicular screw fixation may be considered as an alternative treatment. PMID:19844615

  3. Computed tomographic quantification of canine adrenal gland volume and attenuation.

    PubMed

    Bertolini, Giovanna; Furlanello, Tommaso; De Lorenzi, Davide; Caldin, Marco

    2006-01-01

    We conducted a retrospective study in presumed normal dogs to determine the adrenal gland attenuation and volume values. Multidetector computer tomography (MDCT 16) analysis of the gland was carried out in 48 adult dogs without evidence of adrenal gland disease that underwent CT examination for acute spinal injuries. The mean nonenhanced attenuation value +/- SD of the left adrenal gland was 36.0 +/- 5.3 HU (range: 22.0-42.0 HU). The mean nonenhanced attenuation value +/- SD of the right gland was 34.3 +/- 7.0 HU (range: 20.4-48.6HU). The mean enhanced attenuation value +/- SD were: left gland 101.5 +/- 10.6HU (range: 86.8-128.0 HU), and right gland 97.4 +/- 12.4 HU (range: 58.9-123.6 HU). The mean CT volume +/- SD were: left gland was 0.60 cm3 (range: 0.20-0.95; SD 0.17), and right gland (0.55cm3, range: 0.22-1.01; SD 0.19). Attenuation values and volume data were related to age, weight, and gender, using ANOVA. There was no statistically significant difference between the left and right side or in adrenal measurements, because of body weight class effects. The animal effect was the most important source of variation for all adrenal measurements. Based on our study, CT is an effective method for assessing adrenal characteristics in the dog. Normative CT data are provided to allow estimation of normal adrenal gland size and volume. PMID:17009504

  4. Computed tomographic coronary angiography: how many slices do you need?

    PubMed Central

    Peebles, C

    2006-01-01

    While increasing the number of slices in multislice computed tomography clearly brings benefits in terms of detecting significant coronary disease, heavy calcification remains a problem, as does the high radiation burden PMID:16614268

  5. Computed tomographic anatomy of the canine inner and middle ear.

    PubMed

    Russo, Marco; Covelli, Eugenio M; Meomartino, Leonardo; Lamb, Christopher R; Brunetti, Arturo

    2002-01-01

    A series of high-resolution computed x-ray tomography (CT) images of the normal canine middle and inner ear are presented to serve as a reference for optimal interpretation of clinical CT images of animals with diseases affecting this region. PMID:11866039

  6. [Image characteristics of the computer tomograph (author's transl)].

    PubMed

    Schultz, E; Felix, R; Lackner, K; Bergeder, H D; Thurn, P

    1979-04-01

    In the present paper the images produced by spheres of varying diameter (d = 4,6,8,10 mm) embedded in a homogeneous substance of varying densities (H' = 3,48,93,137 Hounsfield units) as produced by computer tomography were studied. Measurements show that for each sphere diameter there is a minimum contrast between the substance of the sphere and its surroundings which must exist in order to show this sphere by computer tomography. It was also shown that the partial volume effect is of significance for the attenuation of the spheres. The effect of the position of the spheres within the slices to be imaged was studied. The results clearly indicate that in the investigation of small tissue changes in the body, the thickness of the slice and patient displacement should be kept as small as possible. PMID:155606

  7. Computed tomographic identification of calcified optic nerve drusen

    SciTech Connect

    Ramirez, H.; Blatt, E.S.; Hibri, N.S.

    1983-07-01

    Four cases of optic disk drusen were accurately diagnosed with orbital computed tomography (CT). The radiologist should be aware of the characteristic CT finding of discrete calcification within an otherwise normal optic disk. This benign process is easily differentiated from lesions such as calcific neoplastic processes of the posterior globe. CT identification of optic disk drusen is essential in the evaluation of visual field defects, migraine-like headaches, and pseudopapilledema.

  8. Budd-Chiari syndrome: computed tomographic and ultrasonographic findings

    SciTech Connect

    Yang, P.J.; Glazer, G.M.; Bowerman, R.A.

    1983-02-01

    A case of Budd-Chiari syndrome is presented in which computed tomography (CT) and ultrasonography suggested the correct diagnosis and excluded adjacent tumor as the cause of hepatic vein occlusion. The CT appearance in this case (homogeneously increased attenuation of an enlarged caudate lobe) differed from the appearance previously reported (patchy liver enhancement) in Budd-Chiari syndrome. Underlying mechanisms responsible for the different CT appearance are discussed.

  9. Multidetector computed tomographic angiography of the cardiovascular system

    PubMed Central

    Burrill, Joshua; Dabbagh, Zaid; Gollub, Frank; Hamady, Mohamed

    2007-01-01

    The introduction of multidetector computed tomography (MDCT) is considered a dramatic development in CT imaging that has direct implication in the imaging of various systems, in particular the cardiovascular system. The advantages of MDCT are an enormous increase in imaging acquisition speed, more coverage of the patient, and high spatial resolution. This article reviews the recent developments in CT angiography and discusses the clinical application relevant to diagnosis and endovascular treatment of cardiovascular diseases. PMID:17989269

  10. Computed Tomographic Tenography of Normal Equine Digital Flexor Tendon Sheath: An Ex Vivo Study

    PubMed Central

    Lacitignola, Luca; De Luca, Pasquale; Guarracino, Alessandro; Crovace, Antonio

    2015-01-01

    Aim of this study was to document the normal computed tomographic tenography findings of digital flexor tendon sheath. Six ex vivo normal equine forelimbs were used. An axial approach was used to inject 185 mg/mL of iopamidol in a total volume of 60 mL into the digital flexor tendon sheaths. Single-slice helical scans, with 5 mm thickness, spaced every 3 mm, for a pitch of 0.6, and with bone algorithm reconstruction, were performed before and after injections of contrast medium. To obtain better image quality for multiplanar reconstruction and 3D reformatting, postprocessing retroreconstruction was performed to reduce the images to submillimetre thickness. Computed tomographic tenography of digital flexor tendon sheaths could visualize the following main tendon structures for every forelimb in contrast-enhanced images as low densities surrounded by high densities: superficial digital flexor tendon, deep digital flexor tendon, manica flexoria, mesotendons, and synovial recess. Results of this study suggest that computed tomographic tenography can be used with accuracy and sensitivity to evaluate the common disorders of the equine digital flexor tendon sheath and the intrathecal structures. PMID:26185709

  11. Development of an electrical impedance computed tomographic two-phase flows analyzer. Annual technical report for program renewal

    SciTech Connect

    Jones, O.C.

    1993-05-01

    This progress report details the theoretical development, numerical results, experimental design (mechanical), experimental design (electronic), and experimental results for the research program for the development of an electrical impedance computed tomographic two-phase flow analyzer.

  12. [Computed tomographic atlas of benign asbestos related pathology].

    PubMed

    Beigelman-Aubry, C; Ferretti, G; Mompoint, D; Ameille, J; Letourneux, M; Frija, J; Laurent, F

    2007-06-01

    The demonstration by computed tomography of abnormalities related to asbestos is essential for the recognition of industrial disease, the compensation of which has considerable economic consequences. The use of compute tomography, the most reliable technique for the detection of pleuro-parenchymatous abnormalities related to asbestos exposure, has increased considerably in France since the publication of the results of a consensus conference in Paris in 1999. Since that time, developments in technology have noticeably modified the protocols of investigation and increased the sensitivity of the detection of pleural and interstitial parenchymatous abnormalities and of nodules. The technical recommendations and those for the interpretation of pleural and parenchymatous abnormalities need to be well known. They are presented in the form of an atlas that gives detailed criteria for asbestosis, pleural plaques and pleural fibrosis. The diagnosis of pleural plaques depends on the combination of clear limits at the pleural and pulmonary interface, typical topography and multiple, bilateral localization. In the context of asbestos exposure the plaques are characteristic of this exposure, unlike diffuse pleural thickening, crow's feet images, parenchymatous bands and entrapped atalectasis. The writing of the radiological report would be most appropriate on this basis. PMID:17652978

  13. [Computed tomographic atlas of benign asbestos related pathology].

    PubMed

    Beigelman-Aubry, C; Ferretti, G; Mompoint, D; Ameille, J; Letourneux, M; Laurent, F

    2007-06-01

    The demonstration by computed tomography of abnormalities related to asbestos is essential for the recognition of industrial disease, the compensation of which has considerable economic consequences. The use of computed tomography, the most reliable technique for the detection of pleuro-parenchymatous abnormalities related to asbestos exposure, has increased considerably in France since the publication of the results of a consensus conference in Paris in 1999. Since that time, developments in CT technology have noticeably modified the protocols of investigation and increased the sensitivity of the detection of pleural and interstitial parenchymatous abnormalities and of nodules. The technical recommendations and those for the interpretation of pleural and parenchymatous abnormalities need to be well known. They are presented in the form of an atlas that gives detailed criteria for asbestosis, pleural plaques and pleural fibrosis. The diagnosis of pleural plaques depends on the combination of clear limits at the pleural and pulmonary interface, typical topography and multiple, bilateral localization. In the context of asbestos exposure the plaques are characteristic of this exposure, unlike diffuse pleural thickening, crow's feet images, parenchymatous bands and entrapped atalectasis. The writing of the radiological report would be most appropriate on this basis. PMID:17632435

  14. Computed tomographic patterns of intracranial infarcts in Ghanaians.

    PubMed

    Obajimi, M O; Nyame, P K; Jumah, K B; Wiredu, E K

    2002-01-01

    Computed tomography has given a boost to intracranial imaging in general, and the diagnosis of the subtypes of Cerebrovascular Accident (CVA) in particular. In this study of 1,172 cases of CVA examined by Computed Tomography (CT), 552 (47.10%) showed features of cerebral infarction. There was a male prevalence in the study and the mean age was 59.8 years. As in all infarcts the diagnostic appearance was a wedge shaped hypodensity within the brain parenchyma. This was most often found in the parietal lobe (73.6%) and was always without a mass effect. Even though solitary infarcts were frequent, multiple lesions were reported in 9.3% of cases and these group of respondents presented mostly with seizures. Diabetes mellitus was an important predisposing factor and was found in 163% of cases, while hypertension was found in only 9.1% of cases studied. Other CT findings were cerebral and cerebrellar atrophy. Calcification of the falx and the basal ganglia were also noted. PMID:12403033

  15. Maturation of normal primate white matter: computed tomographic correlation

    SciTech Connect

    Quencer, R.M.

    1982-09-01

    Five infant baboons were examined with computed tomography (CT) during the first year of their lives to determine the rate and degree of normal white matter maturation in frontal, occipital, and parietal areas. The increase in CT numbers with age was correlated with gross and histologic specimens. Two phases of maturation were identified: a rapid phase (first 8-12 weeks) and a gradual phase (after 12 weeks). Frontal white matter was the most immature in the immediate postnatal period but it became equal in attenuation to the other regions by 4 weeks of age. Knowledge of white matter maturation rates may be particularly useful in cases of neonatal hypoxia/ischemia where zones of periventricular hypodensity are identified. The failure of such regions to follow a normal rate of maturation may indicate damage to the white matter and have significant prognostic implications.

  16. Recurrent largngeal nerve paralysis: a laryngographic and computed tomographic study

    SciTech Connect

    Agha, F.P.

    1983-07-01

    Vocal cord paralysis is a relatively common entity, usually resulting from a pathologic process of the vagus nerve or its recurrent larynegeal branch. It is rarely caused by intralargngeal lesions. Four teen patients with recurrent laryngeal nerve paralysis (RLNP) were evaluated by laryngography, computed tomography (CT), or both. In the evaluation of the paramedian cord, CT was limited in its ability to differentiate between tumor or RLNP as the cause of the fixed cord, but it yielded more information than laryngography on the structural abnormalities of the larynx and pre-epiglottic and paralaryngeal spaces. Laryngography revealed distinct features of RLNP and is the procedure of choice for evaluation of functional abnormalities of the larynx until further experience with faster CT scanners and dynamic scanning of the larynx is gained.

  17. Computed tomographic diagnosis of intraventricular hemorrhage: etiology and prognosis

    SciTech Connect

    Graeb, D.A.; Robertson, W.D.; Lapointe, J.S.; Nugent, R.A.; Harrison, P.B.

    1982-04-01

    Sixty-eight patients with intraventricular hemorrhage (IVH) diagnosed by computed tomography (CT) were reviewed retrospectively to determine the etiology and prognosis, relationship to delayed hydrocephalus, and effect on neurological outcome. The most common causes were a ruptured aneurysm, trauma, and hypertensive hemorrhage. Ruptured aneurysms of the anterior communicating artery can often be predicted from the nonenhanced CT scan. The total mortality rate was 50%; however, 21% of patients returned to normal or had only mild disability. Patients in whom no cause was identified had a better prognosis. Delayed hydrocephalus was related to the effects of subarachnoid hemorrahage rather than obstruction of the ventricular system by blood. IVH per se is seldon a major factor in the neurological outcome.

  18. Temporomandibular joints: high-resolution computed tomographic evaluation

    SciTech Connect

    Thompson, J.R.; Christiansen, E.; Hasso, A.N.; Hinshaw, D.B. Jr.

    1984-01-01

    High-resolution computed tomography of the temporomandibular joint (TMJ) was performed in 43 patients. Exquisite detail of the face, skull base, and TMJs was obtained with CT using soft tissue and bone algorithms, narrow collimation, and multiplanar images. In 10 patients clinically suspected of joint derangement, CT results were in close agreement with surgical findings and arthrography in 13/15 joints. CT showed indirect signs of disc dislocation, and the dislocated disc itself in 81% of affected joints. In two patients, arthrography with CT proved to be more helpful than conventional arthrography alone. CT without intra-articular contrast material provided information not appreciated on conventional radiogaphs in 28 patients (65%) and was particularly helpful in evaluating patients with disc pathosis and trauma. Early experience with CT of the TMJ shows that it is an excellent method of evaluation at acceptable radiation exposure levels that adds essential information not seen on standard radiographs.

  19. Cone Beam Computed Tomographic Assessment of Bifid Mandibular Condyle

    PubMed Central

    Khojastepour, Leila; Kolahi, Shirin; Panahi, Nazi

    2015-01-01

    Objectives: Differential diagnosis of bifid mandibular condyle (BMC) is important, since it may play a role in temporomandibular joint (TMJ) dysfunctions and joint symptoms. In addition, radiographic appearance of BMC may mimic tumors and/or fractures. The aim of this study was to evaluate the prevalence and orientation of BMC based on cone beam computed tomography (CBCT) scans. Materials and Methods: This cross-sectional study was performed on CBCT scans of paranasal sinuses of 425 patients. In a designated NNT station, all CBCT scans were evaluated in the axial, coronal and sagittal planes to find the frequency of BMC. The condylar head horizontal angulations were also determined in the transverse plane. T-test was used to compare the frequency of BMC between the left and right sides and between males and females. Results: Totally, 309 patients with acceptable visibility of condyles on CBCT scans were entered in the study consisting of 170 (55%) females and 139 (45%) males with a mean age of 39.43±9.7 years. The BMC was detected in 14 cases (4.53%). Differences between males and females, sides and horizontal angulations of condyle of normal and BMC cases were not significant. Conclusion: The prevalence of BMC in the studied population was 4.53%. No significant difference was observed between males and females, sides or horizontal angulations of the involved and uninvolved condyles.

  20. Computed tomographic bronchioarterial ratio for brachycephalic dogs without pulmonary disease.

    PubMed

    Won, Sungjun; Lee, Ahra; Choi, Jihye; Choi, Mincheol; Yoon, Junghee

    2015-01-01

    The bronchoarterial (BA) ratio measured with computed tomography is widely used in human medicine to diagnose bronchial dilation or collapse. Although use of the BA ratio in veterinary medicine has been recently studied, this has not been evaluated in brachycephalic dogs predisposed to bronchial diseases including bronchial collapse. The purpose of this study was to establish BA ratios for brachycephalic dogs and compare the values with those of non-brachycephalic dogs. Twenty-three brachycephalic dogs and 15 non-brachycephalic dogs without clinical pulmonary disease were evaluated. The BA ratio of the lobar bronchi in the left and right cranial as well as the right middle, left, and right caudal lung lobes was measured. No significant difference in mean BA ratio was observed between lung lobes or the individual animals (p = 0.148). The mean BA ratio was 1.08 ± 0.10 (99%CI = 0.98~1.18) for brachycephalic dogs and 1.51 ± 0.05 (99% CI = 1.46~1.56) for the non-brachycephalic group. There was a significant difference between the mean BA ratios of the brachycephalic and non-brachycephalic groups (p = 0.00). Defining the normal limit of the BA ratio for brachycephalic breeds may be helpful for diagnosing bronchial disease in brachycephalic dogs. PMID:25643795

  1. Computed tomographic bronchioarterial ratio for brachycephalic dogs without pulmonary disease

    PubMed Central

    Won, Sungjun; Lee, Ahra; Choi, Jihye; Choi, Mincheol

    2015-01-01

    The bronchoarterial (BA) ratio measured with computed tomography is widely used in human medicine to diagnose bronchial dilation or collapse. Although use of the BA ratio in veterinary medicine has been recently studied, this has not been evaluated in brachycephalic dogs predisposed to bronchial diseases including bronchial collapse. The purpose of this study was to establish BA ratios for brachycephalic dogs and compare the values with those of non-brachycephalic dogs. Twenty-three brachycephalic dogs and 15 non-brachycephalic dogs without clinical pulmonary disease were evaluated. The BA ratio of the lobar bronchi in the left and right cranial as well as the right middle, left, and right caudal lung lobes was measured. No significant difference in mean BA ratio was observed between lung lobes or the individual animals (p = 0.148). The mean BA ratio was 1.08 ± 0.10 (99% CI = 0.98~1.18) for brachycephalic dogs and 1.51 ± 0.05 (99% CI = 1.46~1.56) for the non-brachycephalic group. There was a significant difference between the mean BA ratios of the brachycephalic and non-brachycephalic groups (p = 0.00). Defining the normal limit of the BA ratio for brachycephalic breeds may be helpful for diagnosing bronchial disease in brachycephalic dogs. PMID:25643795

  2. Computed tomographic imaging characteristics of the normal canine lacrimal glands

    PubMed Central

    2014-01-01

    Background The canine lacrimal gland (LG) and accessory lacrimal gland of the third eyelid (TEG) are responsible for production of the aqueous portion of the precorneal tear film. Immune-mediated, toxic, neoplastic, or infectious processes can affect the glands directly or can involve adjacent tissues, with secondary gland involvement. Disease affecting these glands can cause keratoconjunctivitis sicca, corneal ulcers, and loss of vision. Due to their location in the orbit, these small structures are difficult to evaluate and measure, making cross-sectional imaging an important diagnostic tool. The detailed cross-sectional imaging appearance of the LG and TEG in dogs using computed tomography (CT) has not been reported to date. Results Forty-two dogs were imaged, and the length, width, and height were measured and the volume calculated for the LGs & TEGs. The glands were best visualized in contrast-enhanced CT images. The mean volume of the LG was 0.14 cm3 and the TEG was 0.1 cm3. The mean height, width, and length of the LG were, 9.36 mm, 4.29 mm, and 9.35 mm, respectively; the corresponding values for the TEG was 2.02 mm, 9.34 mm, and 7.90 mm. LG and TEG volume were positively correlated with body weight (p < 0.05). Conclusions Contrast-enhanced CT is a valuable tool for noninvasive assessment of canine lacrimal glands. PMID:24886364

  3. COMPUTED TOMOGRAPHIC FEATURES OF PHARYNGEAL NEOPLASIA IN 25 DOGS.

    PubMed

    Carozzi, Gregorio; Zotti, Alessandro; Alberti, Monica; Rossi, Federica

    2015-01-01

    Computed tomography (CT) is commonly used to investigate head tumors in dogs, however little information is available for lesions of the pharyngeal area. The purpose of this multicentric, retrospective, cross-sectional study was to describe the CT findings in a sample of dogs with pathologically confirmed pharyngeal neoplasia and determine whether any CT features allowed differentiation of tumor type. Location of lesions, size and shape, margins, relationship with surrounding structures and vessels, attenuation characteristics and enhancement pattern, regional lymph node changes, and presence of metastasis were recorded by three observers (1 DECVDI). The effect of final diagnosis on each CT feature was tested. A total of 25 dogs were included: 15 with carcinomas, five sarcomas, four melanomas, and one lymphoma. The oropharynx and laryngopharynx were more frequently involved. Among tumor groups, lesions were of similar size, irregularly shaped, had ill-defined margins, and had moderate-to-marked heterogeneous contrast enhancement. Lysis of hyoid bones was recorded in two carcinomas and infiltration of the lingual artery occurred in one case. Marked medial retropharyngeal lymphoadenomegaly was recorded in 11 of 14 carcinomas, in all sarcomas and in two of four melanomas. The single lymphoma case showed ill-defined thickening of the oropharyngeal and laryngeal wall with retropharyngeal and mandibular lymphadenomegaly. Lung metastases were found in two of five sarcomas and two of four melanomas. Findings from the current study did not support the hypothesis that CT features could be used to predict pharyngeal tumor type in dogs. However, CT was helpful for determining mass extension, lymph node involvement, and distant metastatic spread. PMID:26173553

  4. Computed Tomographic measurement of distal femor rotation in Iranian population

    PubMed Central

    Moghtadaei, Mehdi; Moghimi, Javad; Shahhoseini, Gholamreza

    2015-01-01

    Background: Proper rotation of components in total knee arthroplasty (TKA) will largely affect the postoperative outcome. Ethnical variation may affect rotational profile. We aimed to evaluate distal femur rotation in Iranian population using transepicondylar axes. Methods: From a total of 450 knee CT scans and via consecutive sampling, 150 qualified subjects with normal lower extremities alignment were selected comprising 96 (64%) males and 54 (36%) females aging 17-80 years. The posterior condylar angle and condylar twist angles were defined as angles between either surgical epicondylar axis (line connecting lateral epicondylar prominence and the medial sulcus) or clinical epicondylar axis (line connecting most prominent points of both epicondyle) and posterior conylar line. Data were compared among genders. Results: Average age of our samples was 43 years (ranging 11-80). Mean (±sd) values for posterior condylar angle and condylar twist angles were 2.35º (±1.34) and 5.77º (±1.70), respectively. The former variable was not discernible in twenty of our subjects because of obscure medial sulcus. Our findings were totally appeared similar to studies from other ethnicities and the observed minor differences may have originated from amount of osteoarthritis and malalignment. Conclusion: Overall, Iranian distal femur rotational profile was similar to other reports. Some minor observed differences may be partially due to samples’ age and different amount of knee osteoarthritis. It is proposed to rely on several methods for determining rotational profile while performing TKA. Moreover, preoperative computed tomography should be fully scrutinized especially in severely osteoarthitic knees. PMID:26034722

  5. Quantification of Vasa Vasorum Density in Multi-Slice Computed Tomographic Coronary Angiograms: Role of Computed Tomographic Image Voxel Size

    SciTech Connect

    Moritz, R.; Eaker, D; Langheinrich, A; Jorgensen, S; Bohle, R; Ritman, E

    2010-01-01

    This study is motivated by the possibility of using computed tomography (CT) to detect early coronary atherosclerosis by the increased CT values within the arterial wall resulting from vasa vasorum proliferation. Coronary arteries (n = 5) with early atherosclerotic changes were injected with Microfil and scanned (micro-CT). Noise was added to the CT projection data sets (to represent the radiation exposure of current clinical CT scanners) and then reconstructed to generate 3-dimensional images at different voxel sizes. Higher CT values were detected because of contrast agent in vasa vasorum if voxel size was less than (150 {micro}m){sup 3}. Contrast in the main lumen increased the CT values dramatically at voxels greater than (100 {micro}m){sup 3}, whereas CT values of the same specimen without contrast in the main lumen remained constant. Voxel sizes less than (200 {micro}m){sup 3} are needed to quantitate arterial wall opacification due to vasa vasorum proliferation.

  6. Automatic pulmonary vessel segmentation in 3D computed tomographic pulmonary angiographic (CTPA) images

    NASA Astrophysics Data System (ADS)

    Zhou, Chuan; Chan, Heang-Ping; Hadjiiski, Lubomir M.; Patel, Smita; Cascade, Philip N.; Sahiner, Berkman; Wei, Jun; Ge, Jun; Kazerooni, Ella A.

    2006-03-01

    Automatic and accurate segmentation of the pulmonary vessels in 3D computed tomographic angiographic images (CTPA) is an essential step for computerized detection of pulmonary embolism (PE) because PEs only occur inside the pulmonary arteries. We are developing an automated method to segment the pulmonary vessels in 3D CTPA images. The lung region is first extracted using thresholding and morphological operations. 3D multiscale filters in combination with a newly developed response function derived from the eigenvalues of Hessian matrices are used to enhance all vascular structures including the vessel bifurcations and suppress non-vessel structures such as the lymphoid tissues surrounding the vessels. At each scale, a volume of interest (VOI) containing the response function value at each voxel is defined. The voxels with a high response indicate that there is an enhanced vessel whose size matches the given filter scale. A hierarchical expectation-maximization (EM) estimation is then applied to the VOI to segment the vessel by extracting the high response voxels at this single scale. The vessel tree is finally reconstructed by combining the segmented vessels at all scales based on a "connected component" analysis. Two experienced thoracic radiologists provided the gold standard of pulmonary arteries by manually tracking the arterial tree and marking the center of the vessels using a computer graphical user interface. Two CTPA cases containing PEs were used to evaluate the performance. One of these two cases also contained other lung diseases. The accuracy of vessel tree segmentation was evaluated by the percentage of the "gold standard" vessel center points overlapping with the segmented vessels. The result shows that 97.3% (1868/1920) and 92.0% (2277/2476) of the manually marked center points overlapped with the segmented vessels for the cases without and with other lung disease, respectively. The results demonstrate that vessel segmentation using our method is

  7. Organ dose assessment in pediatric fluoroscopy and CT via a tomographic computational phantom of the newborn patient

    NASA Astrophysics Data System (ADS)

    Staton, Robert J.

    Of the various types of imaging modalities used in pediatric radiology, fluoroscopy and computed tomography (CT) have the highest associated radiation dose. While these examinations are commonly used for pediatric patients, little data exists on the magnitude of the organ and effective dose values for these procedures. Calculation of these dose values is necessary because of children's increased sensitivity to radiation and their long life expectancy for which to express radiation's latent effects. In this study, a newborn tomographic phantom has been implemented in a radiation transport code to evaluate organ and effective doses for newborn patients in commonly performed fluoroscopy and CT examinations. Organ doses were evaluated for voiding cystourethrogram (VCUG) fluoroscopy studies of infant patients. Time-sequence analysis was performed for videotaped VCUG studies of five different patients. Organ dose values were then estimated for each patient through Monte Carlo (MC) simulations. The effective dose values of the VCUG examination for five patients ranged from 0.6 mSv to 3.2 mSv, with a mean of 1.8 +/- 0.9 mSv. Organ doses were also assessed for infant upper gastrointestinal (UGI) fluoroscopy exams. The effective dose values of the UGI examinations for five patients ranged from 1.05 mSv to 5.92 mSv, with a mean of 2.90 +/- 1.97 mSv. MC simulations of helical multislice CT (MSCT) exams were also completed using, the newborn tomographic phantom and a stylized newborn phantom. The helical path of the source, beam shaping filter, beam profile, patient table, were all included in the MC simulations of the helical MSCT scanner. Organ doses and effective doses and their dependence on scan parameters were evaluated for newborn patients. For all CT scans, the effective dose was found to range approximately 1-13 mSv, with the largest values occurring for CAP scans. Tube current modulation strategies to reduce patient dose were also evaluated for newborn patients

  8. Mapping Faults from 3-D Tomographic Velocity Model using Image Processing / Computer Vision Algorithms: Application to Northern Cascadia

    NASA Astrophysics Data System (ADS)

    Ramachandran, K.

    2011-12-01

    Three dimensional velocity models constructed through seismic tomography are seldom digitally processed further for imaging structural features. A study conducted to evaluate the potential for imaging subsurface discontinuities in horizontal and vertical direction from three dimensional velocity models using image processing/computer vision techniques has provided significant results. Three-dimensional velocity models constructed through tomographic inversion of active source and/or earthquake traveltime data are generally built from an initial 1-D velocity model that varies only with depth. Regularized tomographic inversion algorithms impose constraints on the roughness of the model that help to stabilize the inversion process. Final velocity models obtained from regularized tomographic inversions have smooth three-dimensional structures that are required by the data. Final velocity models are usually analyzed and interpreted either as a perturbation velocity model or as an absolute velocity model. Compared to perturbation velocity model, absolute velocity model has an advantage of providing constraints on lithology. Both velocity models lack the ability to provide sharp constraints on subsurface faults. However, results from the analysis of the 3-D velocity model from northern Cascadia using Roberts, Prewitt, Sobel, and Canny operators show that subsurface faults that are not clearly interpretable from velocity model plots can be identified through this approach. This analysis resulted in inferring the locations of Tacoma Fault, Seattle Fault, Southern Whidbey Island Fault, and Darrington Devils Mountain fault much clearly. The Coast Range Boundary Fault, previously hypothesized on the basis of sedimentological and tectonic observations is inferred clearly from processed images. Many of the fault locations so imaged correlate with earthquake hypocenters indicating their seismogenic nature.

  9. Experimental Actinobacillus pleuropneumoniae challenge in swine: Comparison of computed tomographic and radiographic findings during disease

    PubMed Central

    2012-01-01

    Background In pigs, diseases of the respiratory tract like pleuropneumonia due to Actinobacillus pleuropneumoniae (App) infection have led to high economic losses for decades. Further research on disease pathogenesis, pathogen-host-interactions and new prophylactic and therapeutic approaches are needed. In most studies, a large number of experimental animals are required to assess lung alterations at different stages of the disease. In order to reduce the required number of animals but nevertheless gather information on the nature and extent of lung alterations in living pigs, a computed tomographic scoring system for quantifying gross pathological findings was developed. In this study, five healthy pigs served as control animals while 24 pigs were infected with App, the causative agent of pleuropneumonia in pigs, in an established model for respiratory tract disease. Results Computed tomographic (CT) findings during the course of App challenge were verified by radiological imaging, clinical, serological, gross pathology and histological examinations. Findings from clinical examinations and both CT and radiological imaging, were recorded on day 7 and day 21 after challenge. Clinical signs after experimental App challenge were indicative of acute to chronic disease. Lung CT findings of infected pigs comprised ground-glass opacities and consolidation. On day 7 and 21 the clinical scores significantly correlated with the scores of both imaging techniques. At day 21, significant correlations were found between clinical scores, CT scores and lung lesion scores. In 19 out of 22 challenged pigs the determined disease grades (not affected, slightly affected, moderately affected, severely affected) from CT and gross pathological examination were in accordance. Disease classification by radiography and gross pathology agreed in 11 out of 24 pigs. Conclusions High-resolution, high-contrast CT examination with no overlapping of organs is superior to radiography in the

  10. Sonography of Gastrointestinal Tract Diseases: Correlation With Computed Tomographic Findings and Endoscopy.

    PubMed

    Ahn, Sung Eun; Moon, Sung Kyoung; Lee, Dong Ho; Park, Seong Jin; Lim, Joo Won; Kim, Hyun Cheol; Lee, Han Na

    2016-07-01

    Sonographic evaluation of the gastrointestinal (GI) tract may be difficult because of overlying intraluminal bowel gas and gas-related artifacts. However, in the absence of these factors and with the development of high-resolution scanners and the technical experience of radiologists, sonography can become a powerful tool for GI tract assessment. This pictorial essay focuses on sonographic findings of GI tract lesions compared with endoscopic, computed tomographic, and magnetic resonance imaging findings. Neoplastic and non-neoplastic diseases and postoperative complications are illustrated, and the distinctive sonographic characteristics of these entities are highlighted. PMID:27268998

  11. The computed tomographic appearance of cerebral cysticercosis in adults and children

    SciTech Connect

    Byrd, S.E.; Locke, G.E.; Biggers, S.; Percy, A.K.

    1982-09-01

    The computed tomographic (CT) scans of 45 patients (30 adults, 15 children) with cerebral cysticercosis were reviewed. These patients had undergone complete diagnostic evaluations including skin tests, laboratory tests, plain skull radiography, radionuclide brain scanning, CT, and cerebral angiography. All of these tests were unrewarding except CT and the indirect hemagglutination tests on the serum. A classification of cerebral cysticercosis based on the location of the lesions in the brain and the CT appearance was developed. Cerebral cysticercosis can be diagnosed by CT findings when there is also a history of seizures and of the patient having lived in an area where the disease is endemic.

  12. Use of spiral computed tomographic angiography in monitoring abdominal aortic aneurysms after transfemoral endovascular repair.

    PubMed Central

    Balm, R; Jacobs, M J

    1997-01-01

    Transfemoral endovascular repair of abdominal aortic aneurysms has proved to be technically feasible in a selected group of patients. However, long-term efficacy has not been proved. Graft performance after implantation can be monitored by a single imaging technique: spiral computed tomographic angiography. With this technique, the parameters for continuing clinical success of the procedure-graft patency, endoleaks, graft migration, attachment site diameter, attachment system failure, and aneurysm diameter-can be monitored. Only in selected cases will an additional imaging technique be necessary. PMID:9339508

  13. Conventional metrizamide myelography (MM) and computed tomographic metrizamide myelography (CTMM) in scoliosis: a comparative study

    SciTech Connect

    Pettersson, H.; Harwood-Nash, D.C.; Fitz, C.R.; Chuang, H.S.; Armstrong, E.

    1982-01-01

    A retrospective examination was performed to assess the accuracy of metrizamide myelography (MM) and computed tomographic metrizamide myelography (CTMM) in scoliosis. Of 81 consecutive scoliotic children studied by myelography, 30 had only MM while the remaining 51 had CTMM immediately afterward. CTMM added esential diagnostic information in 13 cases of dysraphism and 4 cases, both methods gave the same imformation. The outhors conclude that in patients with severe scoliosis, dysraphism, and scoliosis with localized neurological disturbances, CTMM should always be added to MM or be the only examination; while in idiopathic scoliosis with vague neurological disturbances a survey of the entire spine is essential, preferably with MM.

  14. Computed tomographic study of the patterns of oesteoarthritic change which occur on the mandibular condyle.

    PubMed

    Lim, Mi-Ji; Lee, Jeong-Yun

    2014-12-01

    The aim of this study was to investigate which parts of the articular surface of the mandibular condyle are involved in osteoarthritic (OA) change (the occurring pattern) and the relationship of these patterns to clinical signs and symptoms. The computed tomographic (CT) images and clinical records of patients with OA involvement of one or both of their temporomandibular joints (TMJs) were reviewed (OA changes confirmed by CT; 684 TMJs included). The condylar articular surface was divided into nine imaginary sections on the CT images: antero-medial (AM), antero-central (AC), antero-lateral (AL), centri-medial (CM), centri-central (CC), centri-lateral (CL), postero-medial (PM), postero-central (PC), and postero-lateral (PL) section. The occurring patterns were classified with hierarchical cluster analysis based on the distribution of the sections involved by OA changes. OA changes were observed the most frequently on the AC (62.4%) followed by the AM (55.0%), CC (48.2%), AL (43.0%), CL (43.3%), CM (33.3%), PC (28.9%), PL (25.3%), and PM (23.1%). The occurring patterns were classified into three types among which subjective joint pain (P < 0.001) and noise (P < 0.05) were more frequently reported in the entire-involved type followed by lateral- and antero-medial types in descending order, while no significant differences for age, gender, side, pain on palpation, clicking, crepitus, mouth opening range and craniomandibular index were observed. OA changes are more likely to occur on the anterior than the posterior and on the medial than the lateral surface of the mandibular condyle, while subjective joint pain and noise are more frequently reported with OA changes involving the lateral or entire part. Pain on palpation, noise, and mouth opening range were not related to the occurring pattern of OA changes. PMID:25240743

  15. Blood and Sputum Eosinophil Levels in Asthma and Their Relationship to Sinus Computed Tomographic Findings

    PubMed Central

    Mehta, Vinay; Campeau, Norbert G.; Kita, Hirohito; Hagan, John B.

    2010-01-01

    OBJECTIVE To investigate the relationship among blood and sputum eosinophil levels, sinus mucosal thickening, and osteitis in patients with asthma. PATIENTS AND METHODS We conducted an observational study of 201 patients with asthma who underwent sinus computed tomographic (CT) imaging and induced sputum analysis at Mayo Clinic's site in Rochester, MN, from November 1, 2000, through December 31, 2005. Sinus CT scans were reviewed by an investigator blinded to patients' identity and chart information (J.B.H.) to assess for mucosal thickening. Each scan was assigned a CT score based on the Lund-Mackay staging scale. Approximately 20% of the scans were reviewed at random by a radiologist (N.G.C.) to ensure quality control. Bone changes consistent with osteitis were ascertained from radiology reports. Lung function was measured, and sputum was analyzed by conventional methods. RESULTS Sinus CT scans revealed abnormalities in 136 (68%) of the 201 study patients. Severe mucosal thickening (CT score, ≥12) was found in 60 patients (30%) and osteitis in 18 patients (9%). There was a positive correlation between CT scores and eosinophil levels in both peripheral blood (ρ=0.45; 95% confidence interval, 0.33–0.56; P<.001) and induced sputum (ρ=0.46; 95% confidence interval, 0.34–0.57; P<.001). Further, elevated blood and sputum eosinophil levels were associated with the presence of osteitis on CT scan and previous sinus surgery. CONCLUSION Blood and sputum eosinophil levels in patients with asthma are directly correlated with sinus mucosal thickening and are associated with osteitis, lending further support to the hypothesis that asthma and chronic rhinosinusitis are mediated by similar inflammatory processes. PMID:18533084

  16. Tomographic phase analysis to detect the site of accessory conduction pathway in Wolff-Parkinson-White syndrome

    SciTech Connect

    Nakajima, K.; Bunko, H.; Tada, A.; Tonami, N.; Taki, J.; Nanbu, I.; Hisada, K.; Misaki, T.; Iwa, T.

    1984-01-01

    Phase analysis has been applied to Wolff-Parkinson-White syndrome (WPW) to detect the site of accessory conduction pathway (ACP); however, there was a limitation to estimate the precise location of ACP by planar phase analysis. In this study, the authors applied phase analysis to gated blood pool tomography. Twelve patients with WPW who underwent epicardial mapping and surgical division of ACP were studied by both of gated emission computed tomography (GECT) and routine gated blood pool study (GBPS). The GBPS was performed with Tc-99m red blood cells in multiple projections; modified left anterior oblique, right anterior oblique and/or left lateral views. In GECT, short axial, horizontal and vertical long axial blood pool images were reconstructed. Phase analysis was performed using fundamental frequency of the Fourier transform in both GECT and GBPS images, and abnormal initial contractions on both the planar and tomographic phase analysis were compared with the location of surgically confirmed ACPs. In planar phase analysis, abnormal initial phase was identified in 7 out of 12 (58%) patients, while in tomographic phase analysis, the localization of ACP was predicted in 11 out of 12 (92%) patients. Tomographic phase analysis is superior to planar phase images in 8 out of 12 patients to estimate the location of ACP. Phase analysis by GECT can avoid overlap of blood pool in cardiac chambers and has advantage to identify the propagation of phase three-dimensionally. Tomographic phase analysis is a good adjunctive method for patients with WPW to estimate the site of ACP.

  17. PATHOLOGIC BASIS FOR RIM ENHANCEMENT OBSERVED IN COMPUTED TOMOGRAPHIC IMAGES OF FELINE NASOPHARYNGEAL POLYPS.

    PubMed

    Lamb, Christopher R; Sibbing, Kendall; Priestnall, Simon L

    2016-03-01

    In postcontrast computed tomographic (CT) images, feline nasopharyngeal polyps typically demonstrate enhancement of the peripheral rim. Computed tomographic images and histologic specimens of a case series of 22 cats with surgically removed nasopharyngeal polyps were reviewed retrospectively in an attempt to elucidate the origin of rim enhancement. Polyps were present in the tympanic cavity in 15 (68%) cats (three with extension into the nasopharynx), only in the nasopharynx in four (18%) cats, and only in the external ear canal in the remaining three (14%) cats. All polyps had variable degrees of epithelial injury. Hemorrhage and inflammatory infiltration were significantly more marked in the superficial stroma whereas edema was significantly more marked in the core stroma. In noncontrast CT images (n = 22), the tympanic bulla was thickened in all 15 cats with a polyp in the tympanic cavity and enlarged in eight (53%) of these cats. In postcontrast CT images (n = 15), an outer zone of relatively increased attenuation compatible with a rim was observed in 11 (73%) polyps. The magnitude and extent of rim enhancement in CT images was positively correlated with the histologic grade of inflammation in the superficial stroma and negatively correlated with the grade of edema in the superficial stroma. It appears that inflammation is the major determinant of contrast medium accumulation in feline nasopharyngeal polyps, and the tendency for inflammation to affect predominantly the superficial layers explains the frequent observation of a rim in postcontrast CT images. PMID:26763944

  18. Analysis and classification of optical tomographic images of rheumatoid fingers with ANOVA and discriminate analysis

    NASA Astrophysics Data System (ADS)

    Montejo, Ludguier D.; Kim, Hyun K.; Häme, Yrjö; Jia, Jingfei; Montejo, Julio D.; Netz, Uwe J.; Blaschke, Sabine; Zwaka, Paul; Müeller, Gerhard A.; Beuthan, Jürgen; Hielscher, Andreas H.

    2011-03-01

    We present a study on the effectiveness of computer-aided diagnosis (CAD) of rheumatoid arthritis (RA) from frequency-domain diffuse optical tomographic (FDOT) images. FDOT is used to obtain the distribution of tissue optical properties. Subsequently, the non-parametric Kruskal-Wallis ANOVA test is employed to verify statistically significant differences between the optical parameters of patients affected by RA and healthy volunteers. Furthermore, quadratic discriminate analysis (QDA) of the absorption (μa) and scattering (μa or μ's) distributions is used to classify subjects as affected or not affected by RA. We evaluate the classification efficiency by determining the sensitivity (Se), specificity (Sp), and the Youden index (Y). We find that combining features extracted from μa and μa or μ's images allows for more accurate classification than when μa or μa or μ's features are considered individually on their own. Combining μa and μa or μ's features yields values of up to Y = 0.75 (Se = 0.84 and Sp = 0.91). The best results when μa or μ's features are considered individually are Y = 0.65 (Se = 0.85 and Sp = 0.80) and Y = 0.70 (Se = 0.80 and Sp = 0.90), respectively.

  19. Tomographic diagnostics of nonthermal plasmas

    NASA Astrophysics Data System (ADS)

    Denisova, Natalia

    2009-10-01

    In the previous work [1], we discussed a ``technology'' of tomographic method and relations between the tomographic diagnostics in thermal (equilibrium) and nonthermal (nonequilibrium) plasma sources. The conclusion has been made that tomographic reconstruction in thermal plasma sources is the standard procedure at present, which can provide much useful information on the plasma structure and its evolution in time, while the tomographic reconstruction of nonthermal plasma has a great potential at making a contribution to understanding the fundamental problem of substance behavior in strongly nonequilibrium conditions. Using medical terminology, one could say, that tomographic diagnostics of the equilibrium plasma sources studies their ``anatomic'' structure, while reconstruction of the nonequilibrium plasma is similar to the ``physiological'' examination: it is directed to study the physical mechanisms and processes. The present work is focused on nonthermal plasma research. The tomographic diagnostics is directed to study spatial structures formed in the gas discharge plasmas under the influence of electrical and gravitational fields. The ways of plasma ``self-organization'' in changing and extreme conditions are analyzed. The analysis has been made using some examples from our practical tomographic diagnostics of nonthermal plasma sources, such as low-pressure capacitive and inductive discharges. [0pt] [1] Denisova N. Plasma diagnostics using computed tomography method // IEEE Trans. Plasma Sci. 2009 37 4 502.

  20. Computed Tomographic Morphometry of the Internal Anatomy of Mandibular Second Primary Molars

    PubMed Central

    Sharma, Pranjal; Swamy, Dinesh Francis; Shashidara, R; Swamy, Elaine Barretto

    2015-01-01

    ABSTRACT Need for the study: The most important procedure for a successful endodontic treatment is the cleaning and shaping of the canal system. Understanding the internal anatomy of teeth provides valuable information to the clinician that would help him achieve higher clinical success during endodontic therapy. Aims: To evaluate by computed tomography—the internal anatomy of mandibular second primary molars with respect to the number of canals, cross-sectional shape of canals, cross-sectional area of canals and the root dentin thickness. Materials and methods: A total of 31 mandibular second primary molars were subjected to computed-tomographic evaluation in the transverse plane, after mounting them in a prefabricated template. The images, thus, obtained were analyzed using De-winter Bio-wizard® software. Results: All the samples demonstrated two canals in the mesial root, while majority of the samples (65.48%) demonstrated two canals in the distal root. The cross-sectional images of the mesial canals demonstrated a round shape, while the distal canals demonstrated an irregular shape. The root dentin thickness was highly reduced on the distal aspect of mesial and mesial aspect of distal canals. Conclusion: The mandibular second primary molars demonstrated wide variation and complexities in their internal anatomy. A thorough understanding of the complexity of the root canal system is essential for understanding the principles and problems of shaping and cleaning, determining the apical limits and dimensions of canal preparations, and for performing successful endodontic procedures. How to cite this article: Kurthukoti AJ, Sharma P, Swamy DF, Shashidara R, Swamy EB. Computed Tomographic Morphometry of the Internal Anatomy of Mandibular Second Primary Molars. Int J Clin Pediatr Dent 2015;8(3):202-207. PMID:26628855

  1. Optical tomographic detection of rheumatoid arthritis with computer-aided classification schemes

    NASA Astrophysics Data System (ADS)

    Klose, Christian D.; Klose, Alexander D.; Netz, Uwe; Beuthan, Jürgen; Hielscher, Andreas H.

    2009-02-01

    A recent research study has shown that combining multiple parameters, drawn from optical tomographic images, leads to better classification results to identifying human finger joints that are affected or not affected by rheumatic arthritis RA. Building up on the research findings of the previous study, this article presents an advanced computer-aided classification approach for interpreting optical image data to detect RA in finger joints. Additional data are used including, for example, maximum and minimum values of the absorption coefficient as well as their ratios and image variances. Classification performances obtained by the proposed method were evaluated in terms of sensitivity, specificity, Youden index and area under the curve AUC. Results were compared to different benchmarks ("gold standard"): magnet resonance, ultrasound and clinical evaluation. Maximum accuracies (AUC=0.88) were reached when combining minimum/maximum-ratios and image variances and using ultrasound as gold standard.

  2. Rare Root Canal Configuration of Bilateral Maxillary Second Molar Using Cone-beam Computed Tomographic Scanning.

    PubMed

    Zeng, Chang; Shen, Ya; Guan, Xiaoyue; Wang, Xin; Fan, Mingwen; Li, Yuhong

    2016-04-01

    The aim of this article was to present a right maxillary second molar with an unusual root canal morphology of 4 roots and 5 canals as confirmed by cone-beam computed tomographic (CBCT) imaging. The tooth had a C-shaped mesiobuccal root (CBCT imaging revealed that the root was closer to the palate than the buccal side) with 2 canals, 2 fused distobuccal roots with 2 separate canals, and 1 normal bulky palatal root with 1 canal. After thoroughly examining the rare anatomy, root canal treatment was applied on the tooth. This article shows the complexity of maxillary second molar variation and shows the significance of CBCT imaging in the confirmation of the 3-dimensional anatomy of teeth and endodontic treatment. PMID:26920931

  3. Computed tomographic findings in children with spastic diplegia: correlation with the severity of their motor abnormality.

    PubMed

    Yokochi, K; Horie, M; Inukai, K; Kito, H; Shimabukuro, S; Kodama, K

    1989-01-01

    Computed tomographic findings of 46 children with spastic diplegia examined at nine months to three years of age corrected for preterm births were analyzed. Both the size of the lateral ventricles measured by the width of the anterior horns, and the volume of the extracerebral low-density areas were enlarged in some patients. Both enlargements did not, however, correlate to the severity of the motor abnormality in the patients. The low-density areas of the periventricular white matter, especially adjacent to the trigone, were reduced in many children, probably due to the atrophy of the cerebral white matter having periventricular leukomalacia. The anterior expansion of the white matter reduction from the trigone corresponded to the severe motor abnormality in the children with spastic diplegia. PMID:2774092

  4. Myocardial stunning in hypertrophic cardiomyopathy: recovery predicted by single photon emission computed tomographic thallium-201 scintigraphy

    SciTech Connect

    Fine, D.G.; Clements, I.P.; Callahan, M.J.

    1989-05-01

    A young woman with hypertrophic cardiomyopathy confirmed by echocardiography and cardiac catheterization presented with chest pain and features of a large left ventricular aneurysm. The initial diagnosis was myocardial ischemia with either an evolving or an ancient myocardial infarction. Subsequently, verapamil therapy was associated with complete resolution of the extensive left ventricular wall motion abnormalities, normalization of left ventricular ejection fraction and a minimal myocardial infarction. Normal thallium uptake on single photon emission computed tomographic scintigraphy early in the hospital course predicted myocardial viability in the region of the aneurysm. Thus, orally administered verapamil may reverse spontaneous extensive myocardial ischemia in hypertrophic cardiomyopathy and possibly limit the extent of myocardial infarction in such circumstances.

  5. The spine in 3D. Computed tomographic reformation from 2D axial sections.

    PubMed

    Virapongse, C; Gmitro, A; Sarwar, M

    1986-01-01

    A new program (3D83, General Electric) was used to reformat three-dimensional (3D) images from two-dimensional (2D) computed tomographic axial scans in 18 patients who had routine scans of the spine. The 3D spine images were extremely true to life and could be rotated around all three principle axes (constituting a movie), so that an illusion of head-motion parallax was created. The benefit of 3D reformation with this program is primarily for preoperative planning. It appears that 3D can also effectively determine the patency of foraminal stenosis by reformatting in hemisections. Currently this program is subject to several drawbacks that require user interaction and long reconstruction time. With further improvement, 3D reformation will find increasing clinical applicability. PMID:3787319

  6. Computed tomographic evidence of atherosclerosis in the mummified remains of humans from around the world.

    PubMed

    Thompson, Randall C; Allam, Adel H; Zink, Albert; Wann, L Samuel; Lombardi, Guido P; Cox, Samantha L; Frohlich, Bruno; Sutherland, M Linda; Sutherland, James D; Frohlich, Thomas C; King, Samantha I; Miyamoto, Michael I; Monge, Janet M; Valladolid, Clide M; El-Halim Nur El-Din, Abd; Narula, Jagat; Thompson, Adam M; Finch, Caleb E; Thomas, Gregory S

    2014-06-01

    Although atherosclerosis is widely thought to be a disease of modernity, computed tomographic evidence of atherosclerosis has been found in the bodies of a large number of mummies. This article reviews the findings of atherosclerotic calcifications in the remains of ancient people-humans who lived across a very wide span of human history and over most of the inhabited globe. These people had a wide range of diets and lifestyles and traditional modern risk factors do not thoroughly explain the presence and easy detectability of this disease. Nontraditional risk factors such as the inhalation of cooking fire smoke and chronic infection or inflammation might have been important atherogenic factors in ancient times. Study of the genetic and environmental risk factors for atherosclerosis in ancient people may offer insights into this common modern disease. PMID:25667088

  7. Beyond Coronary Stenosis: Coronary Computed Tomographic Angiography for the Assessment of Atherosclerotic Plaque Burden

    PubMed Central

    Kwan, Alan C; Cater, George; Vargas, Jose

    2013-01-01

    Coronary computed tomographic angiography (CCTA) is emerging as a key non-invasive method for assessing cardiovascular risk by measurement of coronary stenosis and coronary artery calcium (CAC). New advancements in CCTA technology have led to the ability to directly identify and quantify the so-called “vulnerable” plaques that have features of positive remodeling and low density components. In addition, CCTA presents a new opportunity for noninvasive measurement of total coronary plaque burden that has not previously been available. The use of CCTA needs also to be balanced by its risks and, in particular, the associated radiation exposure. We review current uses of CCTA, CCTA’s ability to measure plaque quantity and characteristics, and new developments in risk stratification and CCTA technology. CCTA represents a quickly developing field that will play a growing role in the non-invasive management of cardiovascular disease. PMID:23524381

  8. Fluoroscopic and computed tomographic features of the pharyngeal airway in obstructive sleep apnea.

    PubMed

    Suratt, P M; Dee, P; Atkinson, R L; Armstrong, P; Wilhoit, S C

    1983-04-01

    Because it has been suggested that patients with obstructive sleep apnea have a narrower pharyngeal airway than normal persons, we performed lateral fluoroscopy and computed tomographic (CT) scans of the pharynx in patients with this syndrome. Fluoroscopy in 6 sleeping patients showed that the obstruction always began during inspiration when the soft palate touched the tongue and posterior pharyngeal wall. The CT scans in 9 awake subjects demonstrated that the narrowest section of the airway in patients and in control subjects was the region posterior to the soft palate. The cross-sectional area of this region was significantly narrower in patients than it was in control subjects (p less than 0.001). Because a narrow airway would be more likely to collapse during inspiration than a normal one would (Bernoulli's Principle), we conclude that the narrow airways we observed in awake patients may be an important contributing factor in the pathogenesis of obstructive sleep apnea. PMID:6838055

  9. Development of the two Korean adult tomographic computational phantoms for organ dosimetry

    SciTech Connect

    Lee, Choonsik; Lee, Choonik; Park, Sang-Hyun; Lee, Jai-Ki

    2006-02-15

    Following the previously developed Korean tomographic phantom, KORMAN, two additional whole-body tomographic phantoms of Korean adult males were developed from magnetic resonance (MR) and computed tomography (CT) images, respectively. Two healthy male volunteers, whose body dimensions were fairly representative of the average Korean adult male, were recruited and scanned for phantom development. Contiguous whole body MR images were obtained from one subject exclusive of the arms, while whole-body CT images were acquired from the second individual. A total of 29 organs and tissues and 19 skeletal sites were segmented via image manipulation techniques such as gray-level thresholding, region growing, and manual drawing, in which each of segmented image slice was subsequently reviewed by an experienced radiologist for anatomical accuracy. The resulting phantoms, the MR-based KTMAN-1 (Korean Typical MAN-1) and the CT-based KTMAN-2 (Korean Typical MAN-2), consist of 300x150x344 voxels with a voxel resolution of 2x2x5 mm{sup 3} for both phantoms. Masses of segmented organs and tissues were calculated as the product of a nominal reference density, the prevoxel volume, and the cumulative number of voxels defining each organs or tissue. These organs masses were then compared with those of both the Asian and the ICRP reference adult male. Organ masses within both KTMAN-1 and KTMAN-2 showed differences within 40% of Asian and ICRP reference values, with the exception of the skin, gall bladder, and pancreas which displayed larger differences. The resulting three-dimensional binary file was ported to the Monte Carlo code MCNPX2.4 to calculate organ doses following external irradiation for illustrative purposes. Colon, lung, liver, and stomach absorbed doses, as well as the effective dose, for idealized photon irradiation geometries (anterior-posterior and right lateral) were determined, and then compared with data from two other tomographic phantoms (Asian and Caucasian), and

  10. Steady shape analysis of tomographic pumping tests for characterization of aquifer heterogeneities

    USGS Publications Warehouse

    Bohling, G.C.; Zhan, X.; Butler, J.J., Jr.; Zheng, Lingyun

    2002-01-01

    Hydraulic tomography, a procedure involving the performance of a suite of pumping tests in a tomographic format, provides information about variations in hydraulic conductivity at a level of detail not obtainable with traditional well tests. However, analysis of transient data from such a suite of pumping tests represents a substantial computational burden. Although steady state responses can be analyzed to reduce this computational burden significantly, the time required to reach steady state will often be too long for practical applications of the tomography concept. In addition, uncertainty regarding the mechanisms driving the system to steady state can propagate to adversely impact the resulting hydraulic conductivity estimates. These disadvantages of a steady state analysis can be overcome by exploiting the simplifications possible under the steady shape flow regime. At steady shape conditions, drawdown varies with time but the hydraulic gradient does not. Thus transient data can be analyzed with the computational efficiency of a steady state model. In this study, we demonstrate the value of the steady shape concept for inversion of hydraulic tomography data and investigate its robustness with respect to improperly specified boundary conditions.

  11. Data and Analysis from a Time-Resolved Tomographic Optical Beam Diagnostic

    SciTech Connect

    Daniel K. Frayer, Douglas Johnson, Carl Ekdahl

    2010-05-02

    An optical tomographic diagnostic instrument developed for the acquisition of high-speed time-resolved images has been fielded at the Dual-Axis Radiographic Hydrodynamic Test (DARHT) Facility at Los Alamos National Laboratory. The instrument was developed for the creation of time histories of electron-beam cross section through the collection of Cerenkov light. Four optical lines of sight optically collapse an image and relay projections via an optical fiber relay to recording instruments; a tomographic reconstruction algorithm creates the time history. Because the instrument may be operated in an adverse environment, it may be operated, adjusted, and calibrated remotely. The instrument was operated over the course of various activities during and after DARHT commissioning, and tomographic reconstructions reported verifiable beam characteristics. Results from the collected data and reconstructions and analysis of the data are discussed.

  12. Pedicle Morphometry for Thoracic Screw Fixation in Ethnic Koreans : Radiological Assessment Using Computed Tomographic Myelography

    PubMed Central

    Choi, Yong Soo; Yi, Hyeong-Joong; Kim, Young-Joon

    2009-01-01

    Objective In the thoracic spine, insertion of a pedicle screw is annoying due to small pedicle size and wide morphological variation between different levels of the spine and between individuals. The aim of our study was to analyze radiologic parameters of the pedicle morphometry from T1 to T8 using computed tomographic myelography (CTM) in Korean population. Methods For evaluation of the thoracic pedicle morphometry, the authors prospectively analyzed a consecutive series of 26 patients with stable thoracic spines. With the consent of patients, thoracic CTM were performed, from T1 to T8. We calculated the transverse outer diameters and the transverse angles of the pedicle, distance from the cord to the inner cortical wall of the pedicle, and distance from the cord to the dura. Results Transverse outer pedicle diameter was widest at T1 (7.66 ± 2.14 mm) and narrowest at T4 (4.38 ± 1.55 mm). Transverse pedicle angle was widest at T1 (30.2 ± 12.0°) and it became less than 9.0° below T6 level. Theoretical safety zone of the medial perforation of the pedicle screw, namely, distance from the cord to inner cortical wall of the pedicle was more than 4.5 mm. Conclusion Based on this study, we suggest that the current pedicle screw system is not always suitable for Korean patients. Computed tomography is required before performing a transpedicular screw fixation at the thoracic levels. PMID:19893719

  13. Two methods of Haustral fold detection from computed tomographic virtual colonoscopy images

    NASA Astrophysics Data System (ADS)

    Chowdhury, Ananda S.; Tan, Sovira; Yao, Jianhua; Linguraru, Marius G.; Summers, Ronald M.

    2009-02-01

    Virtual colonoscopy (VC) has gained popularity as a new colon diagnostic method over the last decade. VC is a new, less invasive alternative to the usually practiced optical colonoscopy for colorectal polyp and cancer screening, the second major cause of cancer related deaths in industrial nations. Haustral (colonic) folds serve as important landmarks for virtual endoscopic navigation in the existing computer-aided-diagnosis (CAD) system. In this paper, we propose and compare two different methods of haustral fold detection from volumetric computed tomographic virtual colonoscopy images. The colon lumen is segmented from the input using modified region growing and fuzzy connectedness. The first method for fold detection uses a level set that evolves on a mesh representation of the colon surface. The colon surface is obtained from the segmented colon lumen using the Marching Cubes algorithm. The second method for fold detection, based on a combination of heat diffusion and fuzzy c-means algorithm, is employed on the segmented colon volume. Folds obtained on the colon volume using this method are then transferred to the corresponding colon surface. After experimentation with different datasets, results are found to be promising. The results also demonstrate that the first method has a tendency of slight under-segmentation while the second method tends to slightly over-segment the folds.

  14. Assessment of the Radiation Effects of Cardiac Computed Tomographic Angiography Using Protein and Genetic Biomarkers

    PubMed Central

    Nguyen, Patricia K.; Lee, Won Hee; Li, Yong Fuga; Hong, Wan Xing; Hu, Shijun; Chan, Charles; Liang, Grace; Nguyen, Ivy; Ong, Sang-Ging; Churko, Jared; Wang, Jia; Altman, Russ B.; Fleischmann, Dominik; Wu, Joseph C.

    2016-01-01

    Objectives To evaluate whether radiation exposure from cardiac computed tomographic angiography is associated with DNA damage and whether damage leads to programmed cell death and activation of genes involved in apoptosis and DNA repair. Background Exposure to radiation from medical imaging has become a public health concern, but whether it causes significant cell damage remains unclear. Methods We conducted a prospective cohort study in 67 patients undergoing cardiac computed tomographic angiography (CTA) between January 2012 and December 2013 in two US medical centers. Median blood radiation exposure was estimated using phantom dosimetry. Biomarkers of DNA damage and apoptosis were measured by flow cytometry, whole genome sequencing, and single cell polymerase chain reaction. Results The median DLP was 1535.3 mGy·cm (969.7 – 2674.0 mGy·cm). The median radiation dose to the blood was 29.8 milliSieverts (18.8 – 48.8 mSv). Median DNA damage increased 3.39% (1.29 – 8.04%, P<0.0001) post-radiation. Median apoptosis increased 3.1-fold (1.4 – 5.1-fold, P<0.0001) post-radiation. Whole genome sequencing revealed changes in the expression of 39 transcription factors involved in the regulation of apoptosis, cell cycle, and DNA repair. Genes involved in mediating apoptosis and DNA repair were significantly changed post-radiation, including DDB2 [1.9-fold (1.5 – 3.0-fold), P<0.001], XRCC4 [3.0-fold (1.1 – 5.4-fold), P=0.005], and BAX [1.6-fold (0.9 – 2.6-fold), P<0.001]. Exposure to radiation was associated with DNA damage [OR: 1.8 (1.2 – 2.6), P=0.003]. DNA damage was associated with apoptosis [OR: 1.9 (1.2 – 5.1), P<0.0001] and gene activation [OR: 2.8 (1.2 – 6.2), P=0.002]. Conclusions Patients exposed to radiation from cardiac CTA had evidence of DNA damage, which was associated with programmed cell death and activation of genes involved in apoptosis and DNA repair. PMID:26210695

  15. The impact of reorienting cone-beam computed tomographic images in varied head positions on the coordinates of anatomical landmarks

    PubMed Central

    Kim, Jae Hun; Hwang, Jae Joon; Lee, Jung-Hee

    2016-01-01

    Purpose The aim of this study was to compare the coordinates of anatomical landmarks on cone-beam computed tomographic (CBCT) images in varied head positions before and after reorientation using image analysis software. Materials and Methods CBCT images were taken in a normal position and four varied head positions using a dry skull marked with 3 points where gutta percha was fixed. In each of the five radiographic images, reference points were set, 20 anatomical landmarks were identified, and each set of coordinates was calculated. Coordinates in the images from the normally positioned head were compared with those in the images obtained from varied head positions using statistical methods. Post-reorientation coordinates calculated using a three-dimensional image analysis program were also compared to the reference coordinates. Results In the original images, statistically significant differences were found between coordinates in the normal-position and varied-position images. However, post-reorientation, no statistically significant differences were found between coordinates in the normal-position and varied-position images. Conclusion The changes in head position impacted the coordinates of the anatomical landmarks in three-dimensional images. However, reorientation using image analysis software allowed accurate superimposition onto the reference positions. PMID:27358821

  16. Coronary Computed Tomographic Angiography in the Evaluation of Liver Transplant Candidates.

    PubMed

    Poulin, Marie-France; Chan, Edie Y; Doukky, Rami

    2015-10-01

    The feasibility, safety, and value of coronary computed tomographic angiography (CCTA) in evaluating orthotopic liver transplant (OLT) candidates are unknown. We studied a cohort of consecutive OLT candidates with intermediate-to-high risk of coronary artery disease (CAD). Intermediate risk candidates received CCTA, and those at high risk or with abnormal noninvasive testing underwent invasive coronary angiography (ICA). One hundred consecutive patients were evaluated. Fifty patients underwent a CCTA, 71.4% were β-blocked, the image quality was "good" or "excellent" in 71.4% of cases, and there was no event of significant contrast-induced nephropathy. Twenty (20%) patients were found to have severe CAD (≥70% stenosis) by CCTA and/or ICA. Independent predictors of severe CAD were age (odds ratio [OR] = 5.4 per 10-year increment, 95% confidence interval [CI] = 1.7-17.0; P = .004), dyslipidemia (OR = 12.3, 95% CI = 2.6-57.6; P = .001), and chest pain (OR = 6.0, 95% CI = 1.2-29.1; P = .03). Implementing CCTA in the evaluation of intermediate/high CAD risk OLT candidates is challenging but feasible and seems safe. PMID:25520410

  17. Stereotactic interstitial brachytherapy of malignant astrocytomas with remarks on postimplantation computed tomographic appearance

    SciTech Connect

    Willis, B.K.; Heilbrun, M.P.; Sapozink, M.D.; McDonald, P.R.

    1988-09-01

    Seventeen patients were treated with stereotactically implanted high activity iodine-125 seeds, 12 patients for recurrent malignant astrocytomas (Protocol I) and 5 patients for newly diagnosed glioblastomas (Protocol II). Total radiation dosage to the recurrent tumors in Protocol I, including prior external beam irradiation, averaged 13,500 cGy. In the follow-up period of 6 to 50 months, the survival rate was 93% at 6 months, 60% at 12 months, 50% at 18 months, and 38% at 24 months after implantation. In Protocol II, brachytherapy was used as an interstitial radiation boost to the conventional treatment of newly diagnosed glioblastomas. External beam therapy and interstitial brachytherapy provided 11,000 cGy to these tumors. In the follow-up period of 15 to 27 months, there was a 100% survival at 12 months, 75% at 18 months, and 25% at 24 months after implantation. Eight of our 17 patients required reoperation for persistent or recurrent mass lesions at 6 to 15 months postimplantation; 7 were found to harbor masses of radionecrosis containing nests of anaplastic astrocytes; 1 had frank tumor recurrence. Median survival in this group of patients requiring reoperation was 18.7 months postimplantation. In a review of postimplantation computed tomographic scans, significant mass effect and crossover of hypodensity or enhancement into the corpus callosum or opposite hemisphere were found to have prognostic significance; persistent areas of contrast enhancement and excessive peritumoral hypodensity did not.

  18. A negative cranial computed tomographic scan is not adequate to support a diagnosis of pseudotumor cerebri.

    PubMed

    Said, Rana R; Rosman, N Paul

    2004-08-01

    A 10-year-old boy with daily headache for 1 month and intermittent diplopia for 1 week was found to have a unilateral partial abducens palsy and bilateral papilledema; otherwise, his neurologic examination showed no abnormalities. A cranial computed tomographic (CT) scan was normal. Lumbar puncture disclosed a markedly elevated opening pressure of > 550 mm of cerebrospinal fluid with normal cerebrospinal fluid. Medical therapy with acetazolamide for presumed pseudotumor cerebri was begun. Magnetic resonance imaging (MRI) of the brain, done several days later because of continuing symptoms, unexpectedly showed multiple hyperintensities of cerebral white matter on T2-weighted and fluid-attenuated inversion recovery images. Despite high-dose intravenous methylprednisolone for possible demyelinating disease, he failed to improve. A left temporal brain biopsy followed and disclosed an anaplastic oligodendroglioma. In a patient with features indicating pseudotumor cerebri, a negative cranial CT scan is not adequate to rule out underlying pathology; thus, MRI of the brain should probably always be performed. A revised definition of pseudotumor cerebri could better include "normal MRI of the brain" rather than "normal neuroimaging." PMID:15605471

  19. A novel colonic polyp volume segmentation method for computer tomographic colonography

    NASA Astrophysics Data System (ADS)

    Wang, Huafeng; Li, Lihong C.; Han, Hao; Song, Bowen; Peng, Hao; Wang, Yunhong; Wang, Lihua; Liang, Zhengrong

    2014-03-01

    Colorectal cancer is the third most common type of cancer. However, this disease can be prevented by detection and removal of precursor adenomatous polyps after the diagnosis given by experts on computer tomographic colonography (CTC). During CTC diagnosis, the radiologist looks for colon polyps and measures not only the size but also the malignancy. It is a common sense that to segment polyp volumes from their complicated growing environment is of much significance for accomplishing the CTC based early diagnosis task. Previously, the polyp volumes are mainly given from the manually or semi-automatically drawing by the radiologists. As a result, some deviations cannot be avoided since the polyps are usually small (6~9mm) and the radiologists' experience and knowledge are varying from one to another. In order to achieve automatic polyp segmentation carried out by the machine, we proposed a new method based on the colon decomposition strategy. We evaluated our algorithm on both phantom and patient data. Experimental results demonstrate our approach is capable of segment the small polyps from their complicated growing background.

  20. Evaluation of hepatic arterial anatomy by multidetector computed tomographic angiography in living donor liver transplantation.

    PubMed

    Keles, Papatya; Yuce, Ihsan; Keles, Sait; Kantarci, Mecit

    2016-06-01

    The aim of this study was to define the different courses and percentages of hepatic artery that were detected during preoperative evaluation of living liver donors by multidetector computed tomographic angiography (MDCTA). We evaluated 150 donors before hepatic transplantation. All of the donors were evaluated by multislice CT scan with 256 detectors. For each patient, arterial, portal and venous phase images were obtained. The hepatic arterial variations were evaluated by the same radiologist according to Michels' classification. Common hepatic arterial anatomy (type I) was observed in 95 donors (63.3%). Other arterial variations were determined in the remaining 55 donors (36.6%). The second common variation was type XI which did not match with the description of Michels' classification variation in 15 donors (10%). The remaining variations described in Michels' classification were seen at lower rates. Type VII or X variation was not seen. MDCTA is a useful method to identify the blood supply of the liver before the liver transplantations, and surgeons can make their plan on the basis of CT data. PMID:26910605

  1. Assessment of Potential Live Kidney Donors and Computed Tomographic Renal Angiograms at Christchurch Hospital

    PubMed Central

    Mark, Stephen; Armstrong, Sarah; McGregor, David

    2016-01-01

    Aims. To examine the outcome of potential live kidney donors (PLKD) assessment program at Christchurch Hospital and, also, to review findings of Computed Tomographic (CT) renal angiograms that led to exclusion in the surgical assessment. Methods. Clinical data was obtained from the database of kidney transplants, Proton. Radiological investigations were reviewed using the hospital database, Éclair. The transplant coordinator was interviewed to clarify information about PLKD who did not proceed to surgery, and a consultant radiologist was interviewed to explain unfavorable findings on CT renal angiograms. Results. 162 PLKD were identified during the period January 04–June 08. Of those, 65 (40%) proceeded to have nephrectomy, 15 were accepted and planned to proceed to surgery, 13 were awaiting further assessment, and 69 (42.5%) did not proceed to nephrectomy. Of the 162 PLKD, 142 (88%) were directed donors. The proportion of altruistic PLKD who opted out was significantly higher than that of directed PLKD (45% versus 7%, P = 0.00004). Conclusions. This audit demonstrated a positive experience of live kidney donation at Christchurch Hospital. CT renal angiogram can potentially detect incidental or controversial pathologies in the kidney and the surrounding structures. Altruistic donation remains controversial with higher rates of opting out. PMID:27034659

  2. Coronary computer tomographic angiography for preoperative risk stratification in patients undergoing liver transplantation.

    PubMed

    Jodocy, Daniel; Abbrederis, Susanne; Graziadei, Ivo W; Vogel, Wolfgang; Pachinger, Otmar; Feuchtner, Gudrun M; Jaschke, Werner; Friedrich, Guy

    2012-09-01

    The assessment of the cardiovascular risk profile in patients with end-stage liver disease is essential prior to liver transplantation (LT) as cardiovascular diseases are major causes of morbidity and mortality in the posttransplant course. The aim of this study was to evaluate the accuracy of a 64-slice coronary computed tomographic angiography (CTA) and coronary calcium scoring (CCS) to predict the postoperative cardiovascular risk of patients assessed for LT. In this single center, observational study we included 54 consecutive patients who were assessed for LT and consequently transplanted. Twenty-four patients (44%) presented with a high CCS above 300 and/or a significant stenosis (>50% percent narrowing due to stenotic plaques) and were further referred to coronary angiography. Three of these patients had a more than 70% LAD stenosis with subsequent angioplasty (n=1) or conservative therapy (n=2). The other patients showed only diffuse CAD without significant stenosis. The remaining 30 patients with normal CTA findings were listed for LT without further tests. None of the 54 patients developed cardiovascular events peri- and postoperatively. This study indicated that CTA combined with CCS is a useful non-invasive imaging technique for pre-LT assessment of coronary artery disease and safe tool in the risk assessment of peri- and postoperative cardiovascular events in patients undergoing LT. PMID:21665396

  3. Whole-Brain Computed Tomographic Perfusion Imaging in Acute Cerebral Venous Sinus Thrombosis

    PubMed Central

    Mokin, Maxim; Ciambella, Chelsey C.; Masud, Muhammad W.; Levy, Elad I.; Snyder, Kenneth V.; Siddiqui, Adnan H.

    2016-01-01

    Background Acute cerebral venous sinus thrombosis (VST) can be difficult to diagnose because of its diverse clinical presentation. The utility of perfusion imaging for diagnosing VST is not well understood. Summary We retrospectively reviewed cases of acute VST in patients who underwent whole-brain (320-detector-row) computed tomographic (CT) perfusion imaging in combination with craniocervical CT venography. Perfusion maps that were analyzed included cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time, and time to peak. Among the 10 patients with acute VST included in this study, 9 had perfusion abnormalities. All perfusion abnormalities were localized in areas adjacent to the occluded sinus and did not match typical anterior or posterior circulation arterial territories. Bilateral perfusion deficits were seen in 4 cases. In 2 cases, parenchymal hemorrhage was diagnosed on noncontrast CT imaging; in those cases, focal CBV and CBF were reduced. Key Messages Whole-brain CT perfusion imaging with 320-detector-row scanners can further assist in establishing the diagnosis of VST by detecting perfusion abnormalities corresponding to venous and not arterial territories. CT perfusion could assist in the differentiation between focal reversible changes, such as those caused by vasogenic edema, and irreversible changes due to infarction. PMID:27051406

  4. Computed tomographic coronary angiography: experience at Baylor University Medical Center/Baylor Jack and Jane Hamilton Heart and Vascular Hospital

    PubMed Central

    2005-01-01

    Noninvasive cardiac computed tomographic imaging using multislice or electron beam technology has been shown to be highly specific and sensitive in diagnosing coronary heart disease. It is about a fifth of the cost of coronary angiography and is particularly well suited for evaluating patients with a low or low to moderate probability of having obstructive coronary atherosclerosis. In addition, it offers more information than calcium scoring: because of the intravenous contrast used, it temporarily increases the density of the lumen and allows differentiation of soft plaque from calcified plaque. The Baylor Hamilton Heart and Vascular Hospital now uses this modality to define coronary atherosclerosis in patients who would otherwise have needed invasive coronary angiography; several research protocols with the technique are also under way. Baylor has recently upgraded to the 64-slice scanner. It is expected that computed tomographic coronary angiography will replace a significant percentage of invasive cardiac catheterizations. PMID:16200178

  5. Radiographic and computed tomographic demonstration of pseudotumor cerebri due to rapid weight gain in a child with pelvic rhabdomyosarcoma

    SciTech Connect

    Berdon, W.E.; Barker, D.H.; Barash, F.S.

    1982-06-01

    Rapid weight gain in a malnourished child can be associated with suture diastasis in the pattern of pseudotumor cerebri; this has been previously reported in deprivational dwarfism and cystic fibrosis. In a child with pelvic rhabdomyosarcoma, skull radiographs and cranial computed tomographic (CT) scans were available prior to a period of rapid weight gain induced by hyperalimentation. Suture diastasis developed and repeat CT scans showed this to be accompanied by smaller ventricles.

  6. Staging of colorectal cancer using contrast-enhanced multidetector computed tomographic colonography

    PubMed Central

    Narayanan, Srikala; Kalra, Naveen; Bhatia, Anmol; Wig, Jaidev; Rana, Surinder; Bhasin, Deepak; Vaiphei, Kim; Khandelwal, Niranjan

    2014-01-01

    INTRODUCTION Preoperative staging is essential for the optimal treatment and surgical planning of colorectal cancers. This study was aimed to evaluate the accuracy of colorectal cancer staging done using contrast-enhanced multidetector computed tomographic colonography (CEMDCTC). METHODS We recruited 25 patients with 28 proven colorectal cancers. A 16-slice multidetector computed tomography scanner was used to generate two-dimensional multiplanar reformatted sagittal, coronal and oblique coronal images, and three-dimensional virtual colonography (endoluminal) images. Axial and reformatted views were analysed, and TNM staging was done. Patients underwent surgery and conventional colonoscopy, and surgical histopathological correlation was obtained. RESULTS The diagnostic accuracies for TNM colorectal cancer staging were 92.3% for T staging, 42.3% for N staging and 96.1% for M staging using CEMDCTC. There was excellent positive correlation for T staging between CEMDCTC and both surgery (κ-value = 0.686) and histopathology (κ-value = 0.838) (p < 0.0001), and moderate positive correlation for N staging between CEMDCTC and surgery (κ-value = 0.424; p < 0.0001). The correlation between CEMDCTC and histopathology for N staging was poor (κ-value = 0.186; p < 0.05); the negative predictive value was 100% for lymph node detection. Moderate positive correlation was seen for M staging between CEMDCTC and both surgery (κ-value = 0.462) and histopathology (κ-value = 0.649). No false negatives were identified in any of the M0 cases. CONCLUSION CEMDCTC correlated well with pathologic T and M stages, but poorly with pathologic N stage. It is an extremely accurate tool for T staging, but cannot reliably distinguish between malignant lymph nodes and enlarged reactive lymph nodes. PMID:25630322

  7. Automatic centerline extraction of coronary arteries in coronary computed tomographic angiography.

    PubMed

    Yang, Guanyu; Kitslaar, Pieter; Frenay, Michel; Broersen, Alexander; Boogers, Mark J; Bax, Jeroen J; Reiber, Johan H C; Dijkstra, Jouke

    2012-04-01

    Coronary computed tomographic angiography (CCTA) is a non-invasive imaging modality for the visualization of the heart and coronary arteries. To fully exploit the potential of the CCTA datasets and apply it in clinical practice, an automated coronary artery extraction approach is needed. The purpose of this paper is to present and validate a fully automatic centerline extraction algorithm for coronary arteries in CCTA images. The algorithm is based on an improved version of Frangi's vesselness filter which removes unwanted step-edge responses at the boundaries of the cardiac chambers. Building upon this new vesselness filter, the coronary artery extraction pipeline extracts the centerlines of main branches as well as side-branches automatically. This algorithm was first evaluated with a standardized evaluation framework named Rotterdam Coronary Artery Algorithm Evaluation Framework used in the MICCAI Coronary Artery Tracking challenge 2008 (CAT08). It includes 128 reference centerlines which were manually delineated. The average overlap and accuracy measures of our method were 93.7% and 0.30 mm, respectively, which ranked at the 1st and 3rd place compared to five other automatic methods presented in the CAT08. Secondly, in 50 clinical datasets, a total of 100 reference centerlines were generated from lumen contours in the transversal planes which were manually corrected by an expert from the cardiology department. In this evaluation, the average overlap and accuracy were 96.1% and 0.33 mm, respectively. The entire processing time for one dataset is less than 2 min on a standard desktop computer. In conclusion, our newly developed automatic approach can extract coronary arteries in CCTA images with excellent performances in extraction ability and accuracy. PMID:21637981

  8. Three-dimensional computed tomographic evaluation of Le Fort III distraction osteogenesis with an external device in syndromic craniosynostosis.

    PubMed

    Wery, M F; Nada, R M; van der Meulen, J J; Wolvius, E B; Ongkosuwito, E M

    2015-03-01

    There is little anteroposterior growth of the midface in patients with syndromic craniosynostosis who are followed up over time without intervention. A Le Fort III with distraction osteogenesis can be done to correct this. This is a controlled way in which to achieve appreciable stable advancement of the midface without the need for bone grafting, but the vector of the movement is not always predictable. The purpose of this study was to evaluate the 3-dimensional effect of Le Fort III distraction osteogenesis with an external frame. Ten patients (aged 7-19 years) who had the procedure were included in the study. The le Fort III procedure and the placement of the external frame were followed by an activation period and then a 3-month retention period. Computed tomographic (CT) images taken before and after operation were converted and loaded into 3-dimensional image rendering software and compared with the aid of a paired sample t test and a colour-coded qualitative analysis. Comparison of the CT data before and after distraction indicated that the amount of midface advancement was significant. Le Fort III distraction osteogenesis is an effective way to advance the midface. However, the movement during osteogenesis is not always exactly in the intended direction, and a secondary operation is often necessary. Three-dimensional evaluation over a longer period of time is necessary. PMID:25605236

  9. Computed 3D visualisation of an extinct cephalopod using computer tomographs

    NASA Astrophysics Data System (ADS)

    Lukeneder, Alexander

    2012-08-01

    The first 3D visualisation of a heteromorph cephalopod species from the Southern Alps (Dolomites, northern Italy) is presented. Computed tomography, palaeontological data and 3D reconstructions were included in the production of a movie, which shows a life reconstruction of the extinct organism. This detailed reconstruction is according to the current knowledge of the shape and mode of life as well as habitat of this animal. The results are based on the most complete shell known thus far of the genus Dissimilites. Object-based combined analyses from computed tomography and various computed 3D facility programmes help to understand morphological details as well as their ontogentical changes in fossil material. In this study, an additional goal was to show changes in locomotion during different ontogenetic phases of such fossil, marine shell-bearing animals (ammonoids). Hence, the presented models and tools can serve as starting points for discussions on morphology and locomotion of extinct cephalopods in general, and of the genus Dissimilites in particular. The heteromorph ammonoid genus Dissimilites is interpreted here as an active swimmer of the Tethyan Ocean. This study portrays non-destructive methods of 3D visualisation applied on palaeontological material, starting with computed tomography resulting in animated, high-quality video clips. The here presented 3D geometrical models and animation, which are based on palaeontological material, demonstrate the wide range of applications, analytical techniques and also outline possible limitations of 3D models in earth sciences and palaeontology. The realistic 3D models and motion pictures can easily be shared amongst palaeontologists. Data, images and short clips can be discussed online and, if necessary, adapted in morphological details and motion-style to better represent the cephalopod animal.

  10. Computed 3D visualisation of an extinct cephalopod using computer tomographs

    PubMed Central

    Lukeneder, Alexander

    2012-01-01

    The first 3D visualisation of a heteromorph cephalopod species from the Southern Alps (Dolomites, northern Italy) is presented. Computed tomography, palaeontological data and 3D reconstructions were included in the production of a movie, which shows a life reconstruction of the extinct organism. This detailed reconstruction is according to the current knowledge of the shape and mode of life as well as habitat of this animal. The results are based on the most complete shell known thus far of the genus Dissimilites. Object-based combined analyses from computed tomography and various computed 3D facility programmes help to understand morphological details as well as their ontogentical changes in fossil material. In this study, an additional goal was to show changes in locomotion during different ontogenetic phases of such fossil, marine shell-bearing animals (ammonoids). Hence, the presented models and tools can serve as starting points for discussions on morphology and locomotion of extinct cephalopods in general, and of the genus Dissimilites in particular. The heteromorph ammonoid genus Dissimilites is interpreted here as an active swimmer of the Tethyan Ocean. This study portrays non-destructive methods of 3D visualisation applied on palaeontological material, starting with computed tomography resulting in animated, high-quality video clips. The here presented 3D geometrical models and animation, which are based on palaeontological material, demonstrate the wide range of applications, analytical techniques and also outline possible limitations of 3D models in earth sciences and palaeontology. The realistic 3D models and motion pictures can easily be shared amongst palaeontologists. Data, images and short clips can be discussed online and, if necessary, adapted in morphological details and motion-style to better represent the cephalopod animal. PMID:24850976

  11. Computed 3D visualisation of an extinct cephalopod using computer tomographs.

    PubMed

    Lukeneder, Alexander

    2012-08-01

    The first 3D visualisation of a heteromorph cephalopod species from the Southern Alps (Dolomites, northern Italy) is presented. Computed tomography, palaeontological data and 3D reconstructions were included in the production of a movie, which shows a life reconstruction of the extinct organism. This detailed reconstruction is according to the current knowledge of the shape and mode of life as well as habitat of this animal. The results are based on the most complete shell known thus far of the genus Dissimilites. Object-based combined analyses from computed tomography and various computed 3D facility programmes help to understand morphological details as well as their ontogentical changes in fossil material. In this study, an additional goal was to show changes in locomotion during different ontogenetic phases of such fossil, marine shell-bearing animals (ammonoids). Hence, the presented models and tools can serve as starting points for discussions on morphology and locomotion of extinct cephalopods in general, and of the genus Dissimilites in particular. The heteromorph ammonoid genus Dissimilites is interpreted here as an active swimmer of the Tethyan Ocean. This study portrays non-destructive methods of 3D visualisation applied on palaeontological material, starting with computed tomography resulting in animated, high-quality video clips. The here presented 3D geometrical models and animation, which are based on palaeontological material, demonstrate the wide range of applications, analytical techniques and also outline possible limitations of 3D models in earth sciences and palaeontology. The realistic 3D models and motion pictures can easily be shared amongst palaeontologists. Data, images and short clips can be discussed online and, if necessary, adapted in morphological details and motion-style to better represent the cephalopod animal. PMID:24850976

  12. MULTIDETECTOR-ROW COMPUTED TOMOGRAPHIC CHARACTERISTICS OF PRESUMED PREURETERAL VENA CAVA IN CATS.

    PubMed

    Pey, Pascaline; Marcon, Oriana; Drigo, Michele; Specchi, Swan; Bertolini, Giovanna

    2015-01-01

    Preureteral vena cava (circumcaval ureter, retrocaval ureter) occurs in a third of the feline population and has been associated with ureteral strictures in humans. The aim of this retrospective cross-sectional study was to describe the contrast-enhanced multidetector row computed tomographic (MDCT) characteristics of presumed preureteral vena cava in a group of cats. Medical records from two institutions located in different continents were searched from 2010-2013 for cases with complete contrast-enhanced MDCT examinations of the abdomen (i.e. included the entire course of the ureters and prerenal and renal segments of the caudal vena cava) and a diagnosis of preureteral caudal vena cava. For cases meeting inclusion criteria, CT scan data were retrieved and characteristics of the preureteral caudal vena cava were recorded. Presence of concomitant renal or ureteral diseases was also recorded. A total of 272 cats had contrast-enhanced abdominal CT scans during the study period and of these, 68 cats (22.43 ± 4.96%) had a diagnosis of presumed preureteral vena cava. In all affected cats, a "reverse-J ureter" was observed, i.e. a ureter running medially at the level of L4-5, passing dorsally to the caudal vena cava and then exiting ventrally between the caudal vena cava and aorta returning to its normal position. Having a preureteral vena cava resulted in an increased risk for concurrent urinary signs (OR = 3.00; CI: 95%; 1.28-6.99; P = 0.01). Findings supported the use of contrast-enhanced MDCT for characterizing morphology of preureteral vena cava and its relation with ureters in cats. PMID:25786990

  13. A Cone-Beam Computed Tomographic Study on Mandibular First Molars in a Chinese Subpopulation

    PubMed Central

    Ma, Yue; Han, Ting; Chen, Xinyu; Wan, Fang; Lu, Yating; Yan, Songhe; Wang, Yan

    2015-01-01

    The purpose of this study was to conduct a cone-beam computed tomographic (CBCT) investigation on the root and canal configuration of the mandibular first molars, especially the morphology of the disto-lingual (DL) root, in a Chinese subpopulation. A total of 910 CBCT images of the mandibular first molars were collected from 455 patients who underwent CBCT examinations as a preoperative assessment for implants or orthodontic treatment. The following information was analyzed and evaluated: tooth position, gender, root and root canal number per tooth, root canal type of the mesial root(s) and distal root(s), angle of the DL root canal curvature, distance between two distal canal orifices in the teeth with DL root, and angle of disto-buccal canal orifice–disto-lingual canal orifice–mesio-lingual canal orifice (DB-DL-ML). Most of the mandibular first molars (64.9%, n = 591) had two roots with three root canals, and most of the mesial root canals (87.7%, n = 798) were type VI. The prevalence of the DL root was 22.1% (n = 201). The right side had a higher prevalence of DL root than the left side (p<0.05). Additionally, the curvature of the DL root canal were greater in the bucco-lingual (BL) orientation (30.10°±14.02°) than in the mesio-distal (MD) orientation (14.03°± 8.56°) (p<0.05). Overall there was a high prevalence of DL root in the mandibular first molars, and most of the DL roots were curved in different degrees. This study provided detailed information about the root canal morphology of the mandibular first molars in a Chinese subpopulation. PMID:26241480

  14. Computed tomographic morphology and clinical features of extrahepatic portosystemic shunts in 172 dogs in Japan.

    PubMed

    Fukushima, K; Kanemoto, H; Ohno, K; Takahashi, M; Fujiwara, R; Nishimura, R; Tsujimoto, H

    2014-03-01

    Canine extrahepatic congenital portosystemic shunts (EH-cPSS) are classified into several anatomical types, depending on the origin and termination of the shunt vessel. The aim of this retrospective study was to determine the proportion and clinical features of each anatomical shunt type in a population of dogs presented to a veterinary teaching hospital in Japan. Dogs diagnosed with EH-cPSS using computed tomographic (CT) portography were included (n=172) and shunts were classified based on previous reports. Clinical data were collected from case records and analysed statistically. The most common anatomical type was the spleno-phrenic shunt (n=64), followed by the spleno-azygos (n=38), right gastric-caval (n=29), spleno-caval (n=21), right gastric-caval with caudal loop (n=9), right gastric-phrenic (n=6), colono-caval (n=3), spleno-phrenic and azygos (n=1), and porto-caval (n=1) shunts. Spleno-phrenic and spleno-azygos shunts were diagnosed more frequently in older dogs than right gastric-caval and spleno-caval shunts (P<0.05). The portal vein/aortic (PV/Ao) ratio was significantly larger in dogs with spleno-phrenic shunts than in dogs with spleno-azygos, right gastric-caval or spleno-caval shunts (P<0.05). The PV/Ao ratio was significantly larger in dogs with spleno-azygos shunts than in dogs with right gastric-caval shunts. Dogs with spleno-phrenic shunts had significantly lower serum alkaline phosphatase activities than those with right gastric-caval or spleno-caval shunts. Dogs with spleno-phrenic shunts had significantly lower fasting ammonia concentrations than those with spleno-caval shunts. PMID:24512983

  15. Usefulness of Intraprocedural Coronary Computed Tomographic Angiography During Intervention for Chronic Total Coronary Occlusion.

    PubMed

    Kim, Byeong-Keuk; Cho, Iksung; Hong, Myeong-Ki; Chang, Hyuk-Jae; Shin, Dong-Ho; Kim, Jung-Sun; Shin, Sanghoon; Ko, Young-Guk; Choi, Donghoon; Jang, Yangsoo

    2016-06-15

    Although intraprocedural coronary computed tomographic angiography (CCTA) allows for scanning during intervention without relocation of the patient, studies have yet to report on its use during chronic total occlusion (CTO) intervention. Therefore, we investigated the role of CCTA during CTO intervention, particularly whether CCTA could be used to evaluate the location of guidewires. A total of 61 patients scheduled for elective CTO intervention were consecutively enrolled and underwent CCTA and on-site analyses during intervention. Transverse axial and the curved multiplanar images in a 360-degree view were interactively used together to identify the location of guidewires, along with the adjustment of window condition. Intracoronary contrast injection was used for specific cases requiring enhancement of the distal part of the CTO. Most CCTAs were performed to confirm the location of a single guidewire; CCTA was also performed to evaluate parallel (3 patients) or retrograde wires (5 patients). The initial identification rate for guidewire location was 56% with immediate transaxial images, but it significantly increased to 87% after interactive on-site uses of the curved multiplanar images (p <0.001). Cases in which guidewire location could be predicted with CCTA evaluation show a numerically higher success rate than those that could not (83% vs 63%) but not statistical significance (p = 0.174). The mean time for CCTA evaluation and mean radiation dose were 8.6 minutes and 2.9 mSv, respectively. No specific complications occurred after CCTA and CTO procedures. Intraprocedural CCTA for identifying the location of the guidewires is feasible and safe when used for various CTO procedural steps. PMID:27134060

  16. Computed tomographic and radiographic examination of dental structures in South American camelid specimen of different ages

    PubMed Central

    2014-01-01

    Background Tooth root problems and periodontal diseases are common in South American camelids (SAC). The objective was to evaluate and optimize the imaging technique for dental radiography in SAC and to describe the radiographic and computed tomographic (CT) anatomy of normal teeth at different ages. In this study, the heads of 20 healthy SAC slaughtered for meat production or euthanized for reasons not related to dental problems included 7 female and 10 male llamas and 3 male alpacas. Using a standardized protocol, radiographs and CT scans of the 20 specimen were performed. Results The most useful radiographic projections for mandibular and maxillary cheek teeth evaluation turned out to be lateral30°ventral - laterodorsal and lateral30°dorsal - lateroventral with slight separation of the dental arcades respectively. Digital radiographic and CT appearance of the mandibular and maxillary teeth were described from the beginning of mineralization till maturity. In addition the normal range of the CT radio density of different cheek teeth and different dental tissues were measured. Hounsfield units of different dental tissues of SAC turned out to be similar to equids. Deviation, shortening and partial destruction of the distal tooth root of mandibular 09′s and 10′s and of maxillary 09′s was observed and the existence of a common pulp chamber in younger teeth was revealed. Conclusions The present study provides information about the dental imaging morphology in clinically healthy SAC. This basic information provides fundamental knowledge for evaluating images and planning treatments in clinically affected animals. PMID:24393365

  17. Self-Potential data inversion through the integration of spectral analysis and tomographic approaches

    NASA Astrophysics Data System (ADS)

    Di Maio, Rosa; Piegari, Ester; Rani, Payal; Avella, Adolfo

    2016-05-01

    An integrated approach to interpret Self-Potential (SP) anomalies based on spectral analysis and tomographic methods is presented. The Maximum Entropy Method (MEM) is used for providing accurate estimates of the depth of the anomaly source. The 2D tomographic inversion technique, based on the underground Charge Occurrence Probability (COP) function, is, then, used to fully characterize the anomalous body, as the MEM is not helpful in delineating the shape of the anomaly source. The proposed integrated approach is applied for the inversion of synthetic SP data generated by geometrically simple anomalous bodies, such as cylinders and inclined sheets. This numerical study has allowed the determination of mathematical relationships between zero lines of the COP distributions, the polarization angles and the positions along the profile of the causative sources, which have been of great help for interpreting the related SP anomalies. Finally, the analysis of field examples shows the high potential applicability of the proposed integrated approach for SP data inversion.

  18. Self-Potential data inversion through the integration of spectral analysis and tomographic approaches

    NASA Astrophysics Data System (ADS)

    Di Maio, Rosa; Piegari, Ester; Rani, Payal; Avella, Adolfo

    2016-08-01

    An integrated approach to interpret Self-Potential (SP) anomalies based on spectral analysis and tomographic methods is presented. The Maximum Entropy Method (MEM) is used for providing accurate estimates of the depth of the anomaly source. The 2-D tomographic inversion technique, based on the underground charge occurrence probability (COP) function, is, then, used to fully characterize the anomalous body, as the MEM is not helpful in delineating the shape of the anomaly source. The proposed integrated approach is applied for the inversion of synthetic SP data generated by geometrically simple anomalous bodies, such as cylinders and inclined sheets. This numerical study has allowed the determination of mathematical relationships between zero lines of the COP distributions, the polarization angles and the positions along the profile of the causative sources, which have been of great help for interpreting the related SP anomalies. Finally, the analysis of field examples shows the high potential applicability of the proposed integrated approach for SP data inversion.

  19. A multislice positron emission computed tomograph (PETT IV) yielding transverse and longitudinal images.

    PubMed

    Ter-Pogossian, M M; Mullani, N A; Hood, J; Higgins, C S; Currie, C M

    1978-08-01

    We designed, built, and tested a positron emission tomograph (PETT IV) capable of providing seven slices of the human body simultaneously. PETT IV utilizes a moving hexagonal array of 48 scintillation detectors placed around the subject. Each detector consists of a cylindrical activated sodium iodide crystal optically coupled to two photomultiplier tubes. The multislice capability is achieved by comparing the light outputs of the two photomultiplier tubes in each detector. The images are displayed either as transverse or as longitudinal tomographic sections. This system provides high sensitivity and resolution, and permits rapid and accurate three-dimensional imaging of the head and body. PMID:663264

  20. Cost-Effectiveness of Computed Tomographic Colonography Screening for Colorectal Cancer in the Medicare Population

    PubMed Central

    Lansdorp-Vogelaar, Iris; Rutter, Carolyn M.; Savarino, James E.; van Ballegooijen, Marjolein; Kuntz, Karen M.; Zauber, Ann G.

    2010-01-01

    Background The Centers for Medicare and Medicaid Services (CMS) considered whether to reimburse computed tomographic colonography (CTC) for colorectal cancer screening of Medicare enrollees. To help inform its decision, we evaluated the reimbursement rate at which CTC screening could be cost-effective compared with the colorectal cancer screening tests that are currently reimbursed by CMS and are included in most colorectal cancer screening guidelines, namely annual fecal occult blood test (FOBT), flexible sigmoidoscopy every 5 years, flexible sigmoidoscopy every 5 years in conjunction with annual FOBT, and colonoscopy every 10 years. Methods We used three independently developed microsimulation models to assess the health outcomes and costs associated with CTC screening and with currently reimbursed colorectal cancer screening tests among the average-risk Medicare population. We assumed that CTC was performed every 5 years (using test characteristics from either a Department of Defense CTC study or the National CTC Trial) and that individuals with findings of 6 mm or larger were referred to colonoscopy. We computed incremental cost-effectiveness ratios for the currently reimbursed screening tests and calculated the maximum cost per scan (ie, the threshold cost) for the CTC strategy to lie on the efficient frontier. Sensitivity analyses were performed on key parameters and assumptions. Results Assuming perfect adherence with all tests, the undiscounted number life-years gained from CTC screening ranged from 143 to 178 per 1000 65-year-olds, which was slightly less than the number of life-years gained from 10-yearly colonoscopy (152–185 per 1000 65-year-olds) and comparable to that from 5-yearly sigmoidoscopy with annual FOBT (149–177 per 1000 65-year-olds). If CTC screening was reimbursed at $488 per scan (slightly less than the reimbursement for a colonoscopy without polypectomy), it would be the most costly strategy. CTC screening could be cost-effective at

  1. Virtual pathology: a new paradigm for interpretation of computed tomographic colonography

    NASA Astrophysics Data System (ADS)

    Reed, Judd E.; Johnson, C. Daniel

    1998-06-01

    Computed tomographic colonography (CTC or virtual colonoscopy) is a new technique for imaging the colon for the detection of colorectal neoplasm. Early clinical assessment of this procedure has shown that the performance of this test is acceptable for colorectal screening examinations. The current version of CTC utilizes an interactive combination of axial, reformatted 2D and 3D images (from an endoluminal perspective) that are generated in real time. Navigating the colorectum within the virtual endoscopy (VE) metaphor is tedious. To alleviate this problem and free the radiologist to concentrate on diagnosis, a two pass approach has been adopted. In the first pass, the colon is semiautomatically navigated and its midline is recorded. Then in a second pass, the radiologist moves the view point (virtual endoscope tip) along this midline. This second pass alone takes from 15 to 40 minutes per scan. Additional volume rendered displays have been developed which show longer segments of the colon in formats analogous to views which may be seen at autopsy. These include a technique called planar virtual pathology' (PVP) which uses image planes of the two longitudinal transcolonic sections as cut planes within isometric volume rendered images. Scenes are rendered with rays passing orthogonally through these planes from both sides. Each of the four resulting images depicts approximately one half of the inner surface of a 12 cm bowel segment. Interpretation is performed by viewing these colon segments at approximately 8 cm intervals. In this way, the entire colon can be rapidly examined with a minimum of navigational input from the radiologist. Other virtual pathology views have also been developed. These include cylindrical virtual pathology (CVP) and mercator virtual pathology (MVP). CVP views are formed by casting rays perpendicular to a straight line which approximates a segment of the colon midline. These views are analogous to the result of splitting a segment of

  2. Physiological and Computed Tomographic Predictors of Outcome from Lung Volume Reduction Surgery

    PubMed Central

    Washko, George R.; Martinez, Fernando J.; Hoffman, Eric A.; Loring, Stephen H.; Estépar, Raúl San José; Diaz, Alejandro A.; Sciurba, Frank C.; Silverman, Edwin K.; Han, MeiLan K.; DeCamp, Malcolm; Reilly, John J.

    2010-01-01

    Rationale: Previous investigations have identified several potential predictors of outcomes from lung volume reduction surgery (LVRS). A concern regarding these studies has been their small sample size, which may limit generalizability. We therefore sought to examine radiographic and physiologic predictors of surgical outcomes in a large, multicenter clinical investigation, the National Emphysema Treatment Trial. Objectives: To identify objective radiographic and physiological indices of lung disease that have prognostic value in subjects with chronic obstructive pulmonary disease being evaluated for LVRS. Methods: A subset of the subjects undergoing LVRS in the National Emphysema Treatment Trial underwent preoperative high-resolution computed tomographic (CT) scanning of the chest and measures of static lung recoil at total lung capacity (SRtlc) and inspiratory resistance (Ri). The relationship between CT measures of emphysema, the ratio of upper to lower zone emphysema, CT measures of airway disease, SRtlc, Ri, the ratio of residual volume to total lung capacity (RV/TLC), and both 6-month postoperative changes in FEV1 and maximal exercise capacity were assessed. Measurements and Main Results: Physiological measures of lung elastic recoil and inspiratory resistance were not correlated with improvement in either the FEV1 (R = −0.03, P = 0.78 and R = –0.17, P = 0.16, respectively) or maximal exercise capacity (R = –0.02, P = 0.83 and R = 0.08, P = 0.53, respectively). The RV/TLC ratio and CT measures of emphysema and its upper to lower zone ratio were only weakly predictive of postoperative changes in both the FEV1 (R = 0.11, P = 0.01; R = 0.2, P < 0.0001; and R = 0.23, P < 0.0001, respectively) and maximal exercise capacity (R = 0.17, P = 0.0001; R = 0.15, P = 0.002; and R = 0.15, P = 0.002, respectively). CT assessments of airway disease were not predictive of change in FEV1 or exercise capacity in this cohort. Conclusions: The RV/TLC ratio and CT measures

  3. Dual-source computed tomographic coronary angiography: image quality and stenosis diagnosis in patients with high heart rates.

    PubMed

    Zheng, Minwen; Li, Jiayi; Xu, Jian; Chen, Kang; Zhao, Hongliang; Huan, Yi

    2009-01-01

    We sought to evaluate prospectively the effects of heart rate and heart-rate variability on dual-source computed tomographic coronary image quality in patients whose heart rates were high, and to determine retrospectively the accuracy of dual-source computed tomographic diagnosis of coronary artery stenosis in the same patients.We compared image quality and diagnostic accuracy in 40 patients whose heart rates exceeded 70 beats/min with the same data in 40 patients whose heart rates were 70 beats/min or slower. In both groups, we analyzed 1,133 coronary arterial segments. Five hundred forty-five segments (97.7%) in low-heart-rate patients and 539 segments (93.7%) in high-heart-rate patients were of diagnostic image quality. We considered P < 0.05 to be statistically significant. No statistically significant differences between the groups were found in diagnostic-image quality scores of total segments or of any coronary artery, nor were any significant differences found between the groups in the accurate diagnosis of angiographically significant stenosis.Calcification was the chief factor that affected diagnostic accuracy. In high-heart-rate patients, heart-rate variability was significantly related to the diagnostic image quality of all segments (P = 0.001) and of the left circumflex coronary artery (P = 0.016). Heart-rate variability of more than 5 beats/min most strongly contributed to an inability to evaluate segments in both groups. When heart rates rose, the optimal reconstruction window shifted from diastole to systole.The image quality of dual-source computed tomographic coronary angiography at high heart rates enables sufficient diagnosis of stenosis, although variability of heart rates significantly deteriorates image quality. PMID:19436804

  4. Automatic segmentation of the ribs, the vertebral column, and the spinal canal in pediatric computed tomographic images.

    PubMed

    Banik, Shantanu; Rangayyan, Rangaraj M; Boag, Graham S

    2010-06-01

    We propose methods to perform automatic identification of the rib structure, the vertebral column, and the spinal canal in computed tomographic (CT) images of pediatric patients. The segmentation processes for the rib structure and the vertebral column are initiated using multilevel thresholding and the results are refined using morphological image processing techniques with features based on radiological and anatomical prior knowledge. The Hough transform for the detection of circles is applied to a cropped edge map that includes the thoracic vertebral structure. The centers of the detected circles are used to derive the information required for the opening-by-reconstruction algorithm used to segment the spinal canal. The methods were tested on 39 CT exams of 13 patients; the results of segmentation of the vertebral column and the spinal canal were assessed quantitatively and qualitatively by comparing with segmentation performed independently by a radiologist. Using 13 CT exams of six patients, including a total of 458 slices with the vertebra from different sections of the vertebral column, the average Hausdorff distance was determined to be 3.2 mm with a standard deviation (SD) of 2.4 mm; the average mean distance to the closest point (MDCP) was 0.7 mm with SD = 0.6 mm. Quantitative analysis was also performed for the segmented spinal canal with three CT exams of three patients, including 21 slices with the spinal canal from different sections of the vertebral column; the average Hausdorff distance was 1.6 mm with SD = 0.5 mm, and the average MDCP was 0.6 mm with SD = 0.1 mm. PMID:19219504

  5. Prediction of Small Bowel Obstruction Caused by Bezoars Using Risk Factor Categories on Multidetector Computed Tomographic Findings

    PubMed Central

    Kuang, Lian-qin; Cheng, Cheng

    2016-01-01

    Objectives. The aim of this study was to detect factors associated with small bowel obstruction (SBO) caused by bezoars on multidetector computed tomographic findings. Methods. We retrospectively reviewed 61 patients who had bezoars in the small bowels on MDCT. The patients were divided into SBO patients group and non-SBO patients group. The mean values of the diameter, volume, and CT attenuation as well as location and characteristics of the bezoars were compared between the two groups. Multivariate analysis was performed to determine factors associated with SBO. Results. There were 32 patients (52.5%) in the SBO group and 29 patients (47.5%) in the non-SBO group. The bezoars in the SBO group had greater values of each mean diameter and mean volume than those in the non-SBO group (3.2 ± 0.5 cm versus 1.6 ± 0.7 cm, P < 0.0001, 14.9 ± 6.4 cm3 versus 2.5 ± 2.7 cm3, P < 0.0001, resp.) and had a lower CT attenuation than the non-SBO group (55.5 ± 23.4 versus 173.0 ± 68.0, P < 0.0001). The SBO group had higher prevalence of phytobezoar appearance (75.0% versus 10.3%, P < 0.0001). Major diameters of bezoar and phytobezoar were significant independent risk factors associated with SBO (odds ratio = 36.09, 8.26, resp., and P = 0.0004, 0.044, resp.). Conclusions. Major diameter of bezoar or phytobezoar is a potential risk factor associated with SBO. PMID:27403434

  6. Thoracolumbar intradural disc herniation in eight dogs: clinical, low-field magnetic resonance imaging, and computed tomographic myelography findings.

    PubMed

    Tamura, Shinji; Doi, Shoko; Tamura, Yumiko; Takahashi, Kuniaki; Enomoto, Hirokazu; Ozawa, Tsuyoshi; Uchida, Kazuyuki

    2015-01-01

    Intradural disc herniation is a rarely reported cause of neurologic deficits in dogs and few published studies have described comparative imaging characteristics. The purpose of this retrospective cross sectional study was to describe clinical and imaging findings in a group of dogs with confirmed thoracolumbar intradural disc herniation. Included dogs were referred to one of four clinics, had acute mono/paraparesis or paraplegia, had low field magnetic resonance imaging (MRI) and/or computed tomographic myelography, and were diagnosed with thoracolumbar intradural disc herniation during surgery. Eight dogs met inclusion criteria. The prevalence of thoracolumbar intradural disc herniation amongst the total population of dogs that developed a thoracolumbar intervertebral disc herniation and that were treated with a surgical procedure was 0.5%. Five dogs were examined using low-field MRI. Lesions that were suspected to be intervertebral disc herniations were observed; however, there were no specific findings indicating that the nucleus pulposus had penetrated into the subarachnoid space or into the spinal cord parenchyma. Thus, the dogs were misdiagnosed as having a conventional intervertebral disc herniation. An intradural extramedullary disc herniation (three cases) or intramedullary disc herniation (two cases) was confirmed during surgery. By using computed tomographic myelography (CTM) for the remaining three dogs, an intradural extramedullary mass surrounded by an accumulation of contrast medium was observed and confirmed during surgery. Findings from this small sample of eight dogs indicated that CTM may be more sensitive for diagnosing canine thoracolumbar intradural disc herniation than low-field MRI. PMID:25263808

  7. The early development of medial coronoid disease in growing Labrador retrievers: radiographic, computed tomographic, necropsy and micro-computed tomographic findings.

    PubMed

    Lau, S F; Wolschrijn, C F; Hazewinkel, H A W; Siebelt, M; Voorhout, G

    2013-09-01

    Medial coronoid disease (MCD) encompasses lesions of the entire medial coronoid process (MCP), both of the articular cartilage and the subchondral bone. To detect the earliest signs of MCD, radiography and computed tomography were used to monitor the development of MCD in 14 Labrador retrievers, from 6 to 7 weeks of age until euthanasia. The definitive diagnosis of MCD was based on necropsy and micro-computed tomography findings. The frequency of MCD in the dogs studied was 50%. Radiographic findings did not provide evidence of MCD, ulnar subtrochlear sclerosis or blunting of the cranial edge of the MCP. Computed tomography was more sensitive (30.8%) than radiography (0%) in detecting early MCD, with the earliest signs detectable at 14 weeks of age. A combination of the necropsy and micro-computed tomography findings of the MCP showed that MCD was manifested as a lesion of only the subchondral bone in dogs <18 weeks of age. In all dogs (affected and unaffected), there was close contact between the base of the MCP and the proximal radial head in the congruent joints. Computed tomography and micro-computed tomography findings indicated that the lesions of MCD probably originated at the base of the MCP. PMID:23702281

  8. Potential for Higher Treatment Failure in Obese Patients: Correlation of Elevated Body Mass Index and Increased Daily Prostate Deviations From the Radiation Beam Isocenters in an Analysis of 1,465 Computed Tomographic Images

    SciTech Connect

    Wong, James R. Gao Zhanrong; Merrick, Scott; Wilson, Paula; Uematsu, Minoru; Woo, Kevin; Cheng, C.-W.

    2009-09-01

    Purpose: Recent clinical outcome studies on prostate cancer have reported the influence of patient's obesity on the biochemical failure rates after various treatment modalities. In this study, we investigated the effect of patient's physical characteristics on prostate shift in external beam radiotherapy (EBRT) and hypothesized that there maybe a correlation between patient physique and tumor shift. Methods and Materials: A retrospective analysis was performed using data for 117 patients who received image-guided radiation therapy (IGRT) for prostate cancer between January 2005 and April 2007. A total of 1,465 CT scans were analyzed. The standard deviations (SDs) of prostate shifts for all patients, along with patient weight, body mass index (BMI), and subcutaneous adipose-tissue thickness (SAT), were determined. Spearman rank correlation analysis was performed. Results: Of the 117 patients, 26.5% were considered normal weight, 48.7% were overweight, 17.9% were mildly obese, and 6.9% were moderately to severely obese. Notably 1.3%, 1.5%, 2.0%, and 21.2% of the respective shifts were greater than 10 mm in the left-right (LR) direction for the four patient groups, whereas in the anterior-posterior direction the shifts are 18.2%, 12.6%, 6.7%, and 21.0%, respectively. Strong correlations were observed between SAT, BMI, patient weight, and SDs of daily shifts in the LR direction (p < 0.01). Conclusions: The strong correlation between obesity and shift indicates that without image-guided radiation therapy, the target volume (prostate with or without seminal vesicles) may not receive the intended dose for patients who are moderate to severely obese. This may explain the higher recurrence rate with conventional external beam radiation therapy.

  9. TomoPy: a framework for the analysis of synchrotron tomographic data

    PubMed Central

    Gürsoy, Doǧa; De Carlo, Francesco; Xiao, Xianghui; Jacobsen, Chris

    2014-01-01

    Analysis of tomographic datasets at synchrotron light sources (including X-ray transmission tomography, X-ray fluorescence microscopy and X-ray diffraction tomography) is becoming progressively more challenging due to the increasing data acquisition rates that new technologies in X-ray sources and detectors enable. The next generation of synchrotron facilities that are currently under design or construction throughout the world will provide diffraction-limited X-ray sources and are expected to boost the current data rates by several orders of magnitude, stressing the need for the development and integration of efficient analysis tools. Here an attempt to provide a collaborative framework for the analysis of synchrotron tomographic data that has the potential to unify the effort of different facilities and beamlines performing similar tasks is described in detail. The proposed Python-based framework is open-source, platform- and data-format-independent, has multiprocessing capability and supports procedural programming that many researchers prefer. This collaborative platform could affect all major synchrotron facilities where new effort is now dedicated to developing new tools that can be deployed at the facility for real-time processing, as well as distributed to users for off-site data processing. PMID:25178011

  10. TomoPy: a framework for the analysis of synchrotron tomographic data.

    PubMed

    Gürsoy, Dogˇa; De Carlo, Francesco; Xiao, Xianghui; Jacobsen, Chris

    2014-09-01

    Analysis of tomographic datasets at synchrotron light sources (including X-ray transmission tomography, X-ray fluorescence microscopy and X-ray diffraction tomography) is becoming progressively more challenging due to the increasing data acquisition rates that new technologies in X-ray sources and detectors enable. The next generation of synchrotron facilities that are currently under design or construction throughout the world will provide diffraction-limited X-ray sources and are expected to boost the current data rates by several orders of magnitude, stressing the need for the development and integration of efficient analysis tools. Here an attempt to provide a collaborative framework for the analysis of synchrotron tomographic data that has the potential to unify the effort of different facilities and beamlines performing similar tasks is described in detail. The proposed Python-based framework is open-source, platform- and data-format-independent, has multiprocessing capability and supports procedural programming that many researchers prefer. This collaborative platform could affect all major synchrotron facilities where new effort is now dedicated to developing new tools that can be deployed at the facility for real-time processing, as well as distributed to users for off-site data processing. PMID:25178011

  11. multi-scale approaches for full waveform difference inversion and tomographic model analysis

    NASA Astrophysics Data System (ADS)

    Yuan, Y.; Simons, F. J.; Luo, Y.

    2012-12-01

    Tomographic Earth models are solutions to mixed-determined inverse problems, which are formulated to minimize some measure of difference between synthetics and observed data. Typically, the measurement takes the form of a cross-correlation travel-time difference, or it might be the norm of the difference between the entire waveforms, in which case every wiggle is being used to extract information from the data. Full-waveform difference tomography suffers from a slow convergence rate and a danger of converging to local minima. In this presentation, we explore several routes to improving full-waveform inversion strategies for global and regional seismic tomography. First, we will discuss a wavelet-based multi-scale approach that works progressively from low to higher scales, step-by-step involving more details of the waveform. Second, we will discuss a hybrid misfit strategy that combines cross-correlation traveltime and waveform-difference measurements. We will discuss the making of multiscale sensitivity kernels using wavelet decompositions of the seismogram. Lastly, we move to the model space to conduct a multi-scale analysis of global tomographic models using a class of 3-D spherical wavelet bases that are implemented on the ``cubed ball'', the 3-D extension of the ``cubed sphere''. Using this novel transform we study the sparsity of global seismic tomographic models via thresholded reconstruction, and characterize the relative importance and patterns of features in the Earth models via individual and cumulative reconstructions of their wavelet coefficients. Whether on the side of the data, the sensitivity kernels, or in the model space, tomographic inverse problems have much to gain from the flexibility of the wavelet decomposition in one, two and three dimensions, and this on a global, regional or exploration scale, as we show by example. Full waveform difference inversion. The first figure shows our target model with two anomalous regions. The red stars

  12. The Emerging Roles of Coronary Computed Tomographic Angiography: Acute Chest Pain Evaluation and Screening for Asymptomatic Individuals

    PubMed Central

    Chien, Ning; Wang, Tzung-Dau; Chang, Yeun-Chung; Lin, Po-Chih; Tseng, Yao-Hui; Lee, Yee-Fan; Ko, Wei-Chun; Lee, Bai-Chin; Lee, Wen-Jeng

    2016-01-01

    Coronary computed tomographic angiography (CCTA) has been widely available since 2004. After that, the diagnostic accuracy of CCTA has been extensively validated with invasive coronary angiography for detection of coronary arterial stenosis. In this paper, we reviewed the updated evidence of the role of CCTA in both scenarios including acute chest pain and screening in asymptomatic adults. Several large-scale studies have been conducted to evaluate the diagnostic value of CCTA in the context of acute chest pain patients. CCTA could play a role in delivering more efficient care. For risk stratification of asymptomatic patients using CCTA, latest studies have revealed incremental benefits. Future studies evaluating the totality of plaque characteristics may be useful for determining the role of noncalcified plaque for risk stratification in asymptomatic individuals. PMID:27122947

  13. Three-dimensional reconstructions from computed tomographic scans on smartphones and tablets: a simple tutorial for the ward and operating room using public domain software.

    PubMed

    Ketoff, Serge; Khonsari, Roman Hossein; Schouman, Thomas; Bertolus, Chloé

    2014-11-01

    Handling 3-dimensional reconstructions of computed tomographic scans on portable devices is problematic because of the size of the Digital Imaging and Communications in Medicine (DICOM) stacks. The authors provide a user-friendly method allowing the production, transfer, and sharing of good-quality 3-dimensional reconstructions on smartphones and tablets. PMID:25438270

  14. Hyperspectral datacube estimations of binary stars with the Computed Tomographic Imaging Spectrometer (CTIS)

    NASA Astrophysics Data System (ADS)

    Scholl, James F.; Hege, E. Keith; O'Connell, Daniel G.; Dereniak, Eustace L.

    2010-08-01

    Using mathematical techniques recently adapted for the analysis of hyperspectral imaging systems such as the CTIS, we have performed datacube reconstructions for a number of binary star systems. The CTIS images in the visible (420nm to 720nm) wavelength range were obtained in 2001 using the 3.67m Advanced Electro Optical System (AEOS) of the Maui Space Surveillance System (MSSS). These methods used an analytical model of the CTIS to construct an imaging system operator from optical, focal plane array and Computer Generated Holographic (CGH) disperser parameters in the CTIS. We used the adjoint of this operator to construct matched filtered estimates of the datacubes from the image data. In these reconstructions we are able to simultaneously obtain information on the geometry and relative photometry of the binary systems as well as the spectrum for each component of the system.

  15. Analysis of tomographic mineralogical data using YaDiV—Overview and practical case study

    NASA Astrophysics Data System (ADS)

    Friese, Karl-Ingo; Cichy, Sarah B.; Wolter, Franz-Erich; Botcharnikov, Roman E.

    2013-07-01

    We introduce the 3D-segmentation and -visualization software YaDiV to the mineralogical application of rock texture analysis. YaDiV has been originally designed to process medical DICOM datasets. But due to software advancements and additional plugins, this open-source software can now be easily used for the fast quantitative morphological characterization of geological objects from tomographic datasets. In this paper, we give a summary of YaDiV's features and demonstrate the advantages of 3D-stereographic visualization and the accuracy of 3D-segmentation for the analysis of geological samples. For this purpose, we present a virtual and a real use case (here: experimentally crystallized and vesiculated magmatic rocks, corresponding to the composition of the 1991-1995 Unzen eruption, Japan). Especially the spacial representation of structures in YaDiV allows an immediate, intuitive understanding of the 3D-structures, which may not become clear by only looking on 2D-images. We compare our results of object number density calculations with the established classical stereological 3D-correction methods for 2D-images and show that it was possible to achieve a seriously higher quality and accuracy. The methods described in this paper are not dependent on the nature of the object. The fact, that YaDiV is open-source and users with programming skills can create new plugins themselves, may allow this platform to become applicable to a variety of geological scenarios from the analysis of textures in tiny rock samples to the interpretation of global geophysical data, as long as the data are provided in tomographic form.

  16. Three-dimensional segmentation of the tumor mass in computed tomographic images of neuroblastoma

    NASA Astrophysics Data System (ADS)

    Deglint, Hanford J.; Rangayyan, Rangaraj M.; Boag, Graham S.

    2004-05-01

    Tumor definition and diagnosis require the analysis of the spatial distribution and Hounsfield unit (HU) values of voxels in computed tomography (CT) images, coupled with a knowledge of normal anatomy. Segmentation of the tumor in neuroblastoma is complicated by the fact that the mass is almost always heterogeneous in nature; furthermore, viable tumor, necrosis, fibrosis, and normal tissue are often intermixed. Rather than attempt to separate these tissue types into distinct regions, we propose to explore methods to delineate the normal structures expected in abdominal CT images, remove them from further consideration, and examine the remaining parts of the images for the tumor mass. We explore the use of fuzzy connectivity for this purpose. Expert knowledge provided by the radiologist in the form of the expected structures and their shapes, HU values, and radiological characteristics are also incorporated in the segmentation algorithm. Segmentation and analysis of the tissue composition of the tumor can assist in quantitative assessment of the response to chemotherapy and in the planning of delayed surgery for resection of the tumor. The performance of the algorithm is evaluated using cases acquired from the Alberta Children's Hospital.

  17. Shaping Ability of Single-file Systems with Different Movements: A Micro-computed Tomographic Study

    PubMed Central

    Santa-Rosa, Joedy; de Sousa-Neto, Manoel Damião; Versiani, Marco Aurelio; Nevares, Giselle; Xavier, Felipe; Romeiro, Kaline; Cassimiro, Marcely; Leoni, Graziela Bianchi; de Menezes, Rebeca Ferraz; Albuquerque, Diana

    2016-01-01

    Introduction: This study aimed to perform a rigorous sample standardization and also evaluate the preparation of mesiobuccal (MB) root canals of maxillary molars with severe curvatures using two single-file engine-driven systems (WaveOne with reciprocating motion and OneShape with rotary movement), using micro-computed tomography (micro-CT). Methods and Materials: Ten MB roots with single canals were included, uniformly distributed into two groups (n=5). The samples were prepared with a WaveOne or OneShape files. The shaping ability and amount of canal transportation were assessed by a comparison of the pre- and post-instrumentation micro-CT scans. The Kolmogorov-Smirnov and t-tests were used for statistical analysis. The level of significance was set at 0.05. Results: Instrumentation of canals increased their surface area and volume. Canal transportation occurred in coronal, middle and apical thirds and no statistical difference was observed between the two systems (P>0.05). In apical third, significant differences were found between groups in canal roundness (in 3 mm level) and perimeter (in 3 and 4 mm levels) (P<0.05). Conclusion: The WaveOne and One Shape single-file systems were able to shape curved root canals, producing minor changes in the canal curvature. PMID:27471537

  18. Effect of beta blockade on single photon emission computed tomographic (SPECT) thallium-201 images in patients with coronary disease

    SciTech Connect

    Narahara, K.A.; Thompson, C.J.; Hazen, J.F.; Brizendine, M.; Mena, I.

    1989-05-01

    We evaluated the effect of beta blockers on thallium-201 (Tl-201) single photon emission computed tomographic (SPECT) imaging in 12 patients with coronary disease using an automated computer algorithm. Maximal exercise heart rate and blood pressure were reduced and exercise time was increased with beta blockers. Estimated stress defect size decreased from 47 +/- 36.3 gm during placebo treatment to 32 +/- 27.1 gm during beta blocker therapy (-32%; p less than 0.01). The placebo treatment redistribution defect was estimated to be 28 +/- 29.8 gm. It fell to 15 +/- 23.3 gm with beta blockade (-46%; p less than 0.005). All patients had a stress Tl-201 defect during placebo treatment and eight had redistribution defects consistent with residual scar. During beta blocker therapy, 2 of 12 patients had normal stress-redistribution studies and only five patients had redistribution defects. Beta blockade can reduce exercise and redistribution Tl-201 SPECT defect size significantly while simultaneously increasing exercise time and reducing angina. Beta blockers may unmask or may eliminate evidence of redistribution. Tl-201 SPECT imaging may be useful in defining the reduction in ischemia produced by cardiac drugs.

  19. COMPUTED TOMOGRAPHIC APPEARANCE OF MELANOMAS IN THE EQUINE HEAD: 13 CASES.

    PubMed

    Dixon, Jonathon; Smith, Ken; Perkins, Justin; Sherlock, Ceri; Mair, Tim; Weller, Renate

    2016-05-01

    Melanomas are one of the most common neoplasms in the horse and are frequently found in the head region. There is a genetic predisposition in horses with a gray hair coat. Computed tomography (CT) is frequently used in referral practice to evaluate the equine head but there are few reports describing the CT appearance of melanomas in this location. The aim of this retrospective, case series study was to describe characteristics in a group of horses with confirmed disease. Case records from two referral hospitals were reviewed, and 13 horses were identified that had undergone CT of the head, with a diagnosis of melanoma based on cytology, histopathology, or visual assessment of black (melanotic) tissue. A median of 11 melanomas was identified per horse (range 3-60), with a total of 216 masses. Melanomas were found most frequently in the parotid salivary gland, guttural pouches, surrounding the larynx and pharynx and adjacent to the hyoid apparatus. In noncontrast CT images, all melanomas were hyperattenuating (median; 113.5 Hounsfield units (HU), IQR; 26 HU) compared to masseter musculature (median; 69 HU, IQR; 5.5 HU). Fifty-six (25.9%) masses were partially mineralized and 41 (19.4%) included hypoattenuating areas. Histopathological assessment of these melanomas suggested that the hyperattenuation identified was most likely a result of abundant intracytoplasmic melanin pigment. Melanomas of the equine head appeared to have consistent CT features that aided detection of mass lesions and their distribution, although histopathological analysis or visual confirmation should still be obtained for definitive diagnosis. PMID:26799704

  20. Computerized detection of pulmonary embolism in computed tomographic pulmonary angiography (CTPA): improvement of vessel segmentation

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    Vessel segmentation is a fundamental step in an automated pulmonary embolism (PE) detection system. The purpose of this study is to improve the segmentation scheme for pulmonary vessels affected by PE and other lung diseases. We have developed a multiscale hierarchical vessel enhancement and segmentation (MHES) method for pulmonary vessel tree extraction based on the analysis of eigenvalues of Hessian matrices. However, it is difficult to segment the pulmonary vessels accurately when the vessel is occluded by PEs and/or surrounded by lymphoid tissues or lung diseases. In this study, we developed a method that combines MHES with level set refinement (MHES-LSR) to improve vessel segmentation accuracy. The level set was designed to propagate the initial object contours to the regions with relatively high gray-level, high gradient, and high compactness as measured by the smoothness of the curvature along vessel boundaries. Two and eight CTPA scans were randomly selected as training and test data sets, respectively. Forty volumes of interest (VOI) containing "representative" vessels were manually segmented by a radiologist experienced in CTPA interpretation and used as reference standard. The results show that, for the 32 test VOIs, the average percentage volume error relative to the reference standard was improved from 31.7+/-10.9% using the MHES method to 7.7+/-4.7% using the MHES-LSR method. The correlation between the computer-segmented vessel volume and the reference standard was improved from 0.954 to 0.986. The accuracy of vessel segmentation was improved significantly (p<0.05). The MHES-LSR method may have the potential to improve PE detection.

  1. Clinical Application of High-Resolution Computed Tomographic Imaging Features of Community-Acquired Pneumonia

    PubMed Central

    Nie, Yunqiang; Li, Cuiyun; Zhang, Jingling; Wang, Hui; Han, Ping; Lv, Xin; Xu, Xinyi; Guo, Miao

    2016-01-01

    Background This article discusses the value of high-resolution computed tomography (HRCT) in the diagnosis and treatment of pulmonary infections. Lung infection caused by pathogens is an important cause of death. Traditional methods to treat lung infection involved empirical antibiotic therapy. Thin-slice CT scanning is widely used in the clinical setting, and HRCT scan can very clearly show alveolar and bronchiolar involvement of infection. Material/Methods In total, 178 patients with community-acquired pneumonia (CAP) were enrolled. All the patients underwent CT scan, qualified sputum, and blood samples for culture or immunological biochemical tests. CT imaging features, pathogenic bacteria, and treatment results were used for statistical analysis. Results In 77 patients with lobar consolidation, the rate of detection was 43.26% (77/178), and in 101 patients with lobular pneumonia it was 56.74% (101/178). In 51 patients, pathogenic bacteria were detected (28.65%, 51/178). Sixteen of 33 patients detected with bacteria had cavities (48.5%, 16/33) and 35 of 145 patients detected with bacteria had no cavities (24.1%, 35/145). The difference between the 2 groups was statistically significant (χ2=7.795, P=0.005). According to the pathogenic bacteria, 38 patients were cured (74.51%, 38/51), and according to the CT imaging features 81 patients were cured (71.05%, 81/114). No statistically significant difference was found between them (χ2=0.209, P=0.647). Conclusions Treatment effect of CAP based on HRCT findings is not inferior to treatment effect guided by microbial characterization. PMID:27031210

  2. Computed Tomographic Evaluation of K3 Rotary and Stainless Steel K File Instrumentation in Primary Teeth

    PubMed Central

    Kavitha, Swaminathan; Thomas, Eapen; Anadhan, Vasanthakumari; Vijayakumar, Rajendran

    2016-01-01

    Introduction The intention of root canal preparation is to reduce infected content and create a root canal shape allowing for a well condensed root filling. Therefore, it is not necessary to remove excessive dentine for successful root canal preparation and concern must be taken not to over instrument as perforations can occur in the thin dentinal walls of primary molars. Aim This study was done to evaluate the time preparation, the risk of lateral perforation and dentine removal of the stainless steel K file and K3 rotary instrumentation in primary teeth. Materials and Methods Seventy-five primary molars were selected and divided into three groups. Using spiral computed tomography the teeth were scanned before instrumentation. Teeth were prepared using a stainless steel K file for manual technique. All the canals were prepared up to file size 35. In K3 rotary files (.02 taper) instrumentation was done up to 35 size file. In K3 rotary files (.04 taper) the instrumentation was done up to 25 size file and simultaneously the instrumentation time was recorded. The instrumented teeth were once again scanned and the images were compared with the images of the uninstrumented canals. Statistical Analysis Data was statistically analysed using Kruskal Wallis One-way ANOVA, Mann-Whitney U-Test and Pearson’s Chi-square Test. Results K3 rotary files (.02 taper) removed a significantly less amount of dentine, required less instrumentation time than a stainless steel K file. Conclusion K3 files (.02 taper) generated less dentine removal than the stainless steel K file and K3 files (.04 taper). K3 rotary files (.02 taper) were more effective for root canal instrumentation in primary teeth. PMID:26894166

  3. [Multislice computed tomographic angiography in the assessment of central veins for endovascular treatment planning: comparison with phlebography].

    PubMed

    Patanè, Domenico; Morale, Walter; Malfa, Pierantonio; Seminara, Giuseppe; L'Anfusa, Giuseppe; Spanti, Demetrio; Incardona, Concetta; Mandalà, Maria Luisa; Di Landro, Domenico

    2010-01-01

    The dysfunction of a vascular access for hemodialysis and its loss may depend on drainage difficulties of the superficial or deep venation due to hemodynamically significant stenosis or obstruction of a central vein, which generally involve the innominate-subclavian veins or superior vena cava. These alterations are often neglected due to their central and deep location; when there is hemodynamic compensation, they may remain asymptomatic. For these reasons every suspect clinical sign for central vein stenosis (gross arm syndrome or venous hypertension in an arteriovenous fistula) must not be ignored, as timely intervention is essential for functional recovery of the vessel and for the protection of the arteriovenous fistula. The modern imaging techniques ensure thorough diagnostic assessment, while the possibilities of endovascular treatment with interventional radiology allow, in a large proportion of cases, optimal minimally invasive treatment, but above all the recovery of venation in a hemodialyzed patient. We report our experience with multislice computed tomographic angiography (MS-CTA) and reconstruction software for treatment planning of central vein stenosis or obstruction. Forty-nine patients were studied with MS-CTA (GE 16). Images were acquired in the venous phase (120-180 seconds after contrast medium injection) followed by digital vascular reconstruction (AutoBone for bone removal, vessel analysis for caliber and length measurements, thin and curved MIP, MPR). Within a week control phlebography was performed. The venous tree was divided into seven segments and analyzed in a double-blind fashion with a distinction between patent segments, 50-70% stenosis, >70% stenosis, occlusion, and collateral vascular beds. There was excellent correspondence in all the examined segments for patency, >70% stenosis, and occlusion, with high sensitivity (98%), specificity (99.3%), and diagnostic accuracy (99.1%). The binomial test demonstrated a highly significant

  4. Cranial computed tomographic findings in Nigerian women with metastatic breast cancer

    PubMed Central

    Obajimi, Millicent O.; Ogbole, Godwin Inalegwu; Adeniji-Sofoluwe, Adenike T.; Adeleye, Amos O.; Elumelu, Theresa N.; Oluwasola, Abideen O.; Akute, O. O.

    2013-01-01

    Introduction: Brain metastases (BM) occur in up to one-fifth of patients with metastatic breast cancer (MBC). Imaging plays a key role in diagnosis. The pattern and distribution of these changes are also crucial to their management. These patterns have not been fully studied in Nigerian women. Materials and Methods: Retrospective analysis of the findings on the cranial Computed Tomography (CT) scans performed in 59 breast cancer patients with suspected BM treated at the University Teaching Hospital in Ibadan, between 2005 and 2010. The imaging features were evaluated in relation to their clinical characteristics. Results: In the 59 patients studied (mean age 50.9 years ± 11.75 SD), headache (40.7%) and hemiparesis/hemiplegia (16.9%) were the commonest clinical presentation. Lytic skull lesions were seen in 15 patients (25.4%), most commonly in the parietal bones. Thirty-nine patients (66.1%), had parenchymal brain lesions, and only 8 (20.5%) of these were single lesions. Most of the lesions were isodense (19/39; 51.4%) the parietal lobe was the most common site with 50.8% (30/59) occurrence and the leptomeninges the least with 13.6% (8/59). Orbital or sellar region involvement occurred in only two patients. The size of the lesions, was <2 cm in 17 (28.8%), 2-5 cm in 14 (23.7%) and >5 cm in 5 patients. Sixteen (27.1%) patients were free of any lesion either in the skull or brain. Patient presenting with multiple brain lesions were more likely to have skull lesions though this was not statistically significant (P = 0.584). Conclusion: The brain continues to be a sanctuary site for breast cancer metastases and CT imaging remains an invaluable tool in the clinical evaluation and therapeutic management of Nigerian women with BM from MBC. It also appears that the demographic and imaging findings in these patients are similar to other racial groups. PMID:23798799

  5. Tomographic Spectral Imaging with Multivariate Statistical Analysis: Comprehensive 3D Microanalysis.

    PubMed

    Kotula, Paul G; Keenan, Michael R; Michael, Joseph R

    2006-02-01

    A comprehensive three-dimensional (3D) microanalysis procedure using a combined scanning electron microscope (SEM)/focused ion beam (FIB) system equipped with an energy-dispersive X-ray spectrometer (EDS) has been developed. The FIB system was used first to prepare a site-specific region for X-ray microanalysis followed by the acquisition of an electron-beam generated X-ray spectral image. A small section of material was then removed by the FIB, followed by the acquisition of another X-ray spectral image. This serial sectioning procedure was repeated 10-12 times to sample a volume of material. The series of two-spatial-dimension spectral images were then concatenated into a single data set consisting of a series of volume elements or voxels each with an entire X-ray spectrum. This four-dimensional (three real space and one spectral dimension) spectral image was then comprehensively analyzed with Sandia's automated X-ray spectral image analysis software. This technique was applied to a simple Cu-Ag eutectic and a more complicated localized corrosion study where the powerful site-specific comprehensive analysis capability of tomographic spectral imaging (TSI) combined with multivariate statistical analysis is demonstrated. PMID:17481340

  6. Diagnosis of sclerosing cholangitis with technetium 99m-labeled iminodiacetic acid planar and single photon emission computed tomographic scintigraphy

    SciTech Connect

    Rodman, C.A.; Keeffe, E.B.; Lieberman, D.A.; Krishnamurthy, S.; Krishnamurthy, G.T.; Gilbert, S.; Eklem, M.J.

    1987-03-01

    The purpose of this study was to determine whether /sup 99m/Tc-iminodiacetic acid planar biliary scintigraphy combined with single photon emission computed tomography could detect sclerosing cholangitis and provide additional information regarding the extent and severity of disease. Thirteen patients with sclerosing cholangitis and 13 normal control subjects were studied. Scintigraphic results were also compared with previously reported studies of patients with isolated common bile duct obstruction and with primary biliary cirrhosis. The planar scintigraphy in patients with sclerosing cholangitis showed beading or bandlike constrictions of the biliary tract corresponding to lesions seen on cholangiography, and the image pattern was distinctly different from images obtained from patients with isolated common bile duct obstruction or primary biliary cirrhosis. The single photon emission computed tomography images of the liver in patients with sclerosing cholangitis demonstrated multiple focal areas of /sup 99m/Tc-iminodiacetic acid retention, representing bile stasis in intrahepatic bile ducts. Compared to controls, the mean hepatic clearance half-time of /sup 99m/Tc-iminodiacetic acid was markedly delayed in patients with sclerosing cholangitis (6-10 times normal). Individual patients with sclerosing cholangitis had wider variation in isotope clearance half-time from three regions of the liver than patients with isolated common bile duct obstruction, consistent with regional difference in disease severity and variable impairment of bile flow. In 4 patients with sclerosing cholangitis with incomplete filling of the right and left hepatic ducts at cholangiography, planar and single photon emission computed tomographic scintigraphy provided evidence of significant intrahepatic sclerosing cholangitis.

  7. COMPUTED TOMOGRAPHIC, RADIOGRAPHIC, AND ENDOSCOPIC TRACHEAL DIMENSIONS IN ENGLISH BULLDOGS WITH GRADE 1 CLINICAL SIGNS OF BRACHYCEPHALIC AIRWAY SYNDROME.

    PubMed

    Kaye, Benjamin M; Boroffka, Susanne A E B; Haagsman, Annika N; Ter Haar, Gert

    2015-01-01

    Tracheal hypoplasia is commonly seen in English Bulldogs affected with brachycephalic airway syndrome. Previously published diagnostic criteria for tracheal hypoplasia in this breed have been a radiographic tracheal diameter:tracheal inlet ratio (TD:TI) < 0.12 or a tracheal diameter:third rib diameter ratio (TD:3R) < 2.0. Computed tomography has become increasingly used for airway evaluation, however published information is lacking regarding CT tracheal dimensions in English Bulldogs. Objectives of this prospective cross-sectional study were to describe radiographic and CT tracheal dimensions in a sample of clinically normal English Bulldogs and compare these values with tracheoscopy scores. Computed tomography (n = 40), radiography (n = 38), and tracheoscopy (n = 40) studies were performed during a single general anesthesia session for each included dog. Tracheal measurements were recorded at three locations: cervical, thoracic inlet, and thorax. Tracheal diameters were narrowest at the thoracic inlet with all techniques. Computed tomographic measurements averaged 19% greater than radiographic measurements. All included dogs had radiographic tracheal measurements greater than the previously published criteria for tracheal hypoplasia. Mean CT TD:TI was 0.26 (± 0.03, 0.20-0.33), and mean CT TT:3R was 2.27 (± 0.24, 1.71-2.74). Radiographic TD:TI and CT TD:TI were significantly correlated (P = 0.00); however radiographic TT:3R and CT TT:3R were not significantly correlated (P = 0.25). Tracheoscopy identified hypoplastic changes in all dogs and tracheoscopy scores were not correlated with CT or radiography diameter measurements. In conclusion, findings indicated that some CT and radiographic tracheal diameter measurements were comparable in English Bulldogs however diameters for both imaging techniques were not comparable with tracheoscopy scores. PMID:26202379

  8. The use of a computed tomographic application for mobile devices in the diagnosis of oral and maxillofacial surgery.

    PubMed

    Aoki, Eduardo Massaharu; Cortes, Arthur Rodriguez Gonzalez; Arita, Emiko Saito

    2015-01-01

    The aim of the current technical report was to introduce a computed tomographic (CT) application for mobile devices as a diagnostic tool for analyzing CT images. An iPad and an iPhone (Apple, Cuppertino, CA) were used to navigate through multiplanar reconstructions of cone beam CT scans, using an application derived from the OsiriX CT software. Tools and advantages of this method were recorded. In addition, images rendered in the iPad were manipulated during dental implant placement and grafting procedures to follow up and confirm the implant digital planning in real time. The study population consisted of 10 patients. In all cases, it was possible to use image manipulation tools, such as changing contrast and brightness, zooming, rotating, panning, performing both linear and area measurements, and analyzing gray-scale values of a region of interest. Furthermore, it was possible to use the OsiriX application in the dental clinic where the study was conducted, to follow-up the analyzed implant placement and grafting procedures at the chairside. The current findings suggest that technological and practical methods to visualize radiographic images are invaluable resources to improve training, teaching, networking, and the performance of real-time follow-up of oral and maxillofacial surgical procedures. This article discusses the advantages and disadvantages of introducing this new technology in the clinical routine. PMID:25565229

  9. Complimentary Imaging Modalities for Investigating Obscure Gastrointestinal Bleeding: Capsule Endoscopy, Double-Balloon Enteroscopy, and Computed Tomographic Enterography.

    PubMed

    Chu, Ye; Wu, Sheng; Qian, Yuting; Wang, Qi; Li, Juanjuan; Tang, Yanping; Bai, Tingting; Wang, Lifu

    2016-01-01

    Objectives. The complimentary value of computed tomographic enterography (CTE) and double-balloon enteroscopy (DBE) combined with capsule endoscopy (CE) was evaluated in the diagnosis of obscure gastrointestinal bleeding (OGIB). Methods. Patients who received CE examinations at Ruijin Hospital between July 2007 and July 2014 with the indication of OGIB were identified, and those who also underwent DBE and/or CTE were included. Their clinical information was retrieved, and results from each test were compared with findings from the other two examinations. Results. The overall diagnostic yield of CE was comparable with DBE (73.9% versus 60.9%) but was significantly higher than the yield of CTE (87% versus 25%, p < 0.001). The diagnostic yield of angiodysplasia at CE was significantly higher than CTE (73% versus 8%, p < 0.001) and DBE (39.1% versus 17.4%, p = 0.013), while no significant difference was found between the three approaches for small bowel tumors. DBE and CTE identified small bowel diseases undetected or undetermined by CE. Conversely, CE improved diagnosis in the cases with negative CTE and DBE, and findings at initial CE directed further diagnosis made by DBE. Conclusions. Combination of the three diagnostic platforms provides complementary value in the diagnosis of OGIB. PMID:26858753

  10. Renal ultrasonographic and computed tomographic appearance, volume, and function of cats with autosomal dominant polycystic kidney disease.

    PubMed

    Reichle, Jean K; DiBartola, Stephen P; Léveillé, Renée

    2002-01-01

    The purpose of this study was to describe the ultrasonographic (US) and computed tomographic (CT) appearance of autosomal dominant polycystic kidney disease (ADPKD) in cats; to compare renal volume in cats with ADPKD (n = 5; mean age 59 +/- 10 months)) and normal cats (n = 5; mean age 66 +/- 10 months) using 2 imaging modalities, US and CT; and to calculate cyst volume using CT. Glomerular filtration rate (GFR) was determined by 2 methods: 99mTc-diethylene-triaminepentaacetic acid (99mTc-DPTA) scintigraphic uptake and 99-Tc-DTPA plasma clearance. Sonographically, ADPKD affected kidneys were characterized by multiple anechoic to hypoechoic, round to irregularly shaped structures with variation in size. Affected kidneys had indistinct corticomedullary junctions and foci of mineralization. Intravenous (IV) contrast medium administration allowed more definitive identification of cysts with CT, and identification of distortion of renal pelves by cysts. A significant difference (Welch ANOVA, P = 0.05) was detected between the US-estimated renal volumes of normal and affected cats. No statistically significant differences were detected in CT volume (between the normal and affected cats, or between US and CT volume measurements) or the 2 GFR methods. In this group of clinically normal, middle-aged ADPKD cats, renal function was within normal limits and not significantly different than normal. PMID:12175002

  11. Complimentary Imaging Modalities for Investigating Obscure Gastrointestinal Bleeding: Capsule Endoscopy, Double-Balloon Enteroscopy, and Computed Tomographic Enterography

    PubMed Central

    Chu, Ye; Wu, Sheng; Qian, Yuting; Wang, Qi; Li, Juanjuan; Tang, Yanping; Bai, Tingting; Wang, Lifu

    2016-01-01

    Objectives. The complimentary value of computed tomographic enterography (CTE) and double-balloon enteroscopy (DBE) combined with capsule endoscopy (CE) was evaluated in the diagnosis of obscure gastrointestinal bleeding (OGIB). Methods. Patients who received CE examinations at Ruijin Hospital between July 2007 and July 2014 with the indication of OGIB were identified, and those who also underwent DBE and/or CTE were included. Their clinical information was retrieved, and results from each test were compared with findings from the other two examinations. Results. The overall diagnostic yield of CE was comparable with DBE (73.9% versus 60.9%) but was significantly higher than the yield of CTE (87% versus 25%, p < 0.001). The diagnostic yield of angiodysplasia at CE was significantly higher than CTE (73% versus 8%, p < 0.001) and DBE (39.1% versus 17.4%, p = 0.013), while no significant difference was found between the three approaches for small bowel tumors. DBE and CTE identified small bowel diseases undetected or undetermined by CE. Conversely, CE improved diagnosis in the cases with negative CTE and DBE, and findings at initial CE directed further diagnosis made by DBE. Conclusions. Combination of the three diagnostic platforms provides complementary value in the diagnosis of OGIB. PMID:26858753

  12. Magnetic resonance and computed tomographic features of 4 cases of canine congenital thoracic vertebral anomalies

    PubMed Central

    Berlanda, Michele; Zotti, Alessandro; Brandazza, Giada; Poser, Helen; Calò, Pietro; Bernardini, Marco

    2011-01-01

    Magnetic resonance and computed tomography features of 4 cases of canine congenital vertebral anomalies (CVAs) are discussed. Two of the cases represent unusual presentations for such anomalies that commonly affect screw-tail or toy breeds. Moreover, the combination of CVAs and a congenital peritoneo-pericardial diaphragmatic hernia has never before been imaged. PMID:22654139

  13. Magnetic resonance and computed tomographic features of 4 cases of canine congenital thoracic vertebral anomalies.

    PubMed

    Berlanda, Michele; Zotti, Alessandro; Brandazza, Giada; Poser, Helen; Calò, Pietro; Bernardini, Marco

    2011-12-01

    Magnetic resonance and computed tomography features of 4 cases of canine congenital vertebral anomalies (CVAs) are discussed. Two of the cases represent unusual presentations for such anomalies that commonly affect screw-tail or toy breeds. Moreover, the combination of CVAs and a congenital peritoneo-pericardial diaphragmatic hernia has never before been imaged. PMID:22654139

  14. Fermionic computation is non-local tomographic and violates monogamy of entanglement

    NASA Astrophysics Data System (ADS)

    D'Ariano, G. M.; Manessi, F.; Perinotti, P.; Tosini, A.

    2014-07-01

    We show that the computational model based on local fermionic modes in place of qubits does not satisfy local tomography and monogamy of entanglement, and has mixed states with maximal entanglement of formation. These features directly follow from the parity superselection rule. We generalize quantum superselection rules to general probabilistic theories as sets of linear constraints on the convex set of states. We then provide a link between the cardinality of the superselection rule and the degree of holism of the resulting theory.

  15. Sector computed tomographic spine scanning in the diagnosis of lumbar nerve root entrapment

    SciTech Connect

    Risius, B.; Modic, M.T.; Hardy, R.W. Jr.; Duchesneau, P.M.; Weinstein, M.A.

    1982-04-01

    The diagnosis of lumbar nerve root entrapment was made by sector computed tomography (CT) scanning in 25 patients whose myelograms were normal at the site of the CT scan abnormalities. Sector CT scanning demonstrates preoperatively which neural foramina are narrow. This information, correlated with the patient's history and physical examination, indicates which foramina should be operated on and prevents unnecessary exploration of normal neutral foramina. CT findings were confirmed surgically in 14 patients. Eleven of these 14 patients had excellent postoperative results and remain pain free.

  16. Computed tomographic detection of sinusitis responsible for intracranial and extracranial infections

    SciTech Connect

    Carter, B.L.; Bankoff, M.S.; Fisk, J.D.

    1983-06-01

    Computed tomography (CT) is now used extensively for the evaluation of orbital, facial, and intracranial infections. Nine patients are presented to illustrate the importance of detecting underlying and unsuspected sinusitis. Prompt treatment of the sinusitis is essential to minimize the morbidity and mortality associated with complications such as brain abscess, meningitis, orbital cellulitis, and osteomyelitis. A review of the literature documents the persistence of these complications despite the widespread use of antibiotic therapy. Recognition of the underlying sinusitis is now possible with CT if the region of the sinuses is included and bone-window settings are used during the examination of patients with orbital and intracranial infection.

  17. Tomographic images of breast tissues obtained by Compton scattering: An analytical computational study

    NASA Astrophysics Data System (ADS)

    Antoniassi, M.; Poletti, M. E.; Brunetti, A.

    2015-11-01

    In this work, we studied by analytical simulation the potential of a Compton scatter technique for breast imaging application. A Compton scattering tomography system was computationally simulated in order to provide the projection data (scattering signal) for the image reconstructions. The simulated projections generated by the analytical proposed method were validated through comparison with those obtained by Monte Carlo simulation. Electron density images were obtained from the scattering signal using a reconstruction algorithm implemented for the system geometry. Finally, the quality of the reconstructed images was evaluated for different sample sizes, beam energies, and tissue compositions (glandularities).

  18. Image formation and system analysis of a scanning tomographic acoustic microscope

    NASA Astrophysics Data System (ADS)

    Kent, Samuel Davis, III

    This dissertation focuses on research that has been conducted to implement an automated Scanning Tomographic Acoustic Microscope (STAM), and research that has been performed to increase the understanding of the performance characteristics of the STAM. STAM technology permits high resolution microscopy which yields important information on the internal structure and acoustic properties of thick specimens, provided that technology is utilized in a cohesive manner. Prior to the research conducted for this dissertation, only a proof-of-concept STAM had been developed; actual STAM imaging was difficult and impractical. This dissertation describes the hardware and software development that has led to the first automated STAM. It focuses on significant problems that were encountered and their solutions. Specifically, accurate data acquisition necessitated the development of special-purpose data acquisition hardware, rotational controls, frequency controls, and automation controls. Inaccuracies in the laser scanning hardware were identified as a significant source of reconstruction error. This error was removed by estimation and correction algorithms. Rotation of the specimen for multiple-angle tomography required the development of a noise-tolerant projection-pose estimation algorithm. An iterative technique for image enhancement is also presented. The resulting STAM system is evaluated to determine its performance characteristics. A component-wise resolution analysis is presented that specifies the resolution-limit in both range and cross-range. The dependency of reconstruction quality on accurate representation of the magnitude and phase of the detected wave fields is also provided.

  19. Analysis of unsectioned specimens: 2D and tomographic PIXE with STIM

    NASA Astrophysics Data System (ADS)

    Schofield, Robert M. S.; Lefevre, Harlan W.

    1993-05-01

    Two techniques for quantitative analysis of heterogeneous thick specimens are reviewed. First, a measurement of the total zinc content in the abdomen of a fly is reported. The calculation used to determine the uncertainty in this measurement is detailed. STIM measurements at two different angles were used to determine the possible range of the X-ray production cross section and the X-ray attenuation factors. The abdomen content of zinc was determined to be 0.022( + 0.009, -0.006) (μg. Second, a PIXE-STIM mutomographic determination of metal concentrations in the sting of a scorpion is reviewed. STIM tomography was used to determine the X-ray production cross sections and the X-ray attenuation factors for points inside of the specimen. Details of how this information was then used for reconstructions of PIXE tomographic data are given. Finally, 2D PIXE measurements on a thick section of this sting are reported. On this section the measured concentration of zinc reached 22(± 3)% of dry mass, in satisfactory agreement with the results from tomography, 25(± 3)%.

  20. Cone Beam Computed Tomographic Evaluation and Diagnosis of Mandibular First Molar with 6 Canals

    PubMed Central

    Pasha, Shiraz; Chaitanya, Bathula Vimala; Somisetty, Kusum Valli

    2016-01-01

    Root canal treatment of tooth with aberrant root canal morphology is very challenging. So thorough knowledge of both the external and internal anatomy of teeth is an important aspect of root canal treatment. With the advancement in technology it is imperative to use modern diagnostic tools such as magnification devices, CBCT, microscopes, and RVG to confirm the presence of these aberrant configurations. However, in everyday endodontic practice, clinicians have to treat teeth with atypical configurations for root canal treatment to be successful. This case report presents the management of a mandibular first molar with six root canals, four in mesial and two in distal root, and also emphasizes the use and importance of Cone Beam Computed Tomography (CBCT) as a diagnostic tool in endodontics. PMID:26904310

  1. Carcinoma of the larynx and hypopharynx: computed tomographic-histopathologic correlations

    SciTech Connect

    Silverman, P.M.; Bossen, E.H.; Fisher, S.R.; Cole, T.B.; Korobkin, M.; Halvorsen, R.A.

    1984-06-01

    Twenty consecutive patients underwent computed tomography (CT) prior to total laryngectomy in order to assess the accuracy of CT scanning in the evaluation of carcinoma of the larynx and hypopharynx. CT scans were prospectively interpreted and the extent of tumor was recorded graphically at five major levels of the larynx. The extent of tumor was similarly evaluated on whole-mount histologic sections of the laryngeal specimens prepared in the horizontal plane similar to the CT scans. The results were compared to assess the ability of CT to identify tumor extent accurately. Despite good correlation of gross tumor extent between histologic specimens and TC scanning, specific pitfalls in CT diagnosis were identified. Overestimation of tumor extent was caused by edematous changes in six patients and tumor-associated inflammatory changes in three patients. In seven patients, mass effect from adjacent bulky tumor significantly distorted normal structures, mimicking tumor involvement.

  2. Meckel cave: computed tomographic study. Part I. Normal anatomy. Part II. Pathology

    SciTech Connect

    Kapila, A.; Chakeres, D.W.; Blanco, E.

    1984-08-01

    A formalin-fixed cadaver head with air filling the cisternal and ventricular spaces was scanned by high-resolution computed tomography (CT) in multiple planes (axial, coronal, and sagittal) through the Meckel cave. Correlation of the CT appearance of the Meckel cave was made with an anatomic dissection and whole-head band saw cross-sections. CT techniques allowed consistent and accurate definition of the Meckel cave, the fifth cranial nerve, and adjacent anatomic structures. CT findings of 13 patients with lesions of the Meckel cave are also reviewed, including six trigeminal schwannomas, three meningiomas, two secondary tumors, one glioma, and one congenital fatty tumor. Surgical confirmation was present in 11 cases. Diagnosis and determination of the extent of Meckel cave lesions is possible with the use of high-resolution CT.

  3. Multicolor Computed Tomographic Molecular Imaging with Non-crystalline High Metal Density Nanobeacons

    PubMed Central

    Pan, Dipanjan; Schirra, Carsten O.; Wickline, Samuel A; Lanza, Gregory M

    2014-01-01

    Computed tomography (CT) is one of the most frequently pursued radiology technologies applied in the clinics today and in the preclinical field of biomedical imaging. Myriad advancement has been made to make this technique more powerful with improved signal sensitivity, rapid image acquisition and faster reconstruction. Synergistic development of novel nanoparticles has been adopted as the next generation CT contrasts agents for imaging specific biological markers. Nanometer-sized agents are anticipated to play a critical part in the prospect of medical diagnostics owing to their capabilities of targeting specific biological markers, extended blood circulation time and defined biological clearance. This review paper introduces the readers to the fundamental design principles of nanoparticulate CT contrast agents with a special emphasis on the molecular Imaging with non-crystalline high metal density nanobeacons. PMID:24470291

  4. Intracranial lesions in the acquired immunodeficiency syndrome: radiological (computed tomographic) features

    SciTech Connect

    Elkin, C.M.; Leon, E.; Grenell, S.L.; Leeds, N.E.

    1985-01-18

    Computed tomography (CT) delineates the presence or absence of intracerebral focal lesions in most instances. The presence of contrast enhancement, cerebral atrophy, and an intracranial mass are important in consideration of the differential diagnosis and in establishing the diagnosis. Initially the authors utilized a double dose of contrast medium in all patients after single-dose study, but little additional information was obtained. A second dose of contrast medium is now administered only to evaluate further a suspected lesion. Angiography can confirm the location of the lesion(s) and the cortical veins before biopsy. Of one hundred patients with AIDS examined, 33% had neurological symptoms excluding headache and herpes zoster. All patients with neurological symptoms were studied with noncontrast and contrast CT scanning. Twenty-seven patients in the group had abnormal scans. In 13, the abnormality was limited to a diffuse atrophic appearance, while in 14, focal lesions were identified. Representative cases are discussed and illustrated.

  5. Computed Tomographic Features in a Case of Bilateral Neoplastic Cryptorchidism with Suspected Torsion in a Dog

    PubMed Central

    Stokowski, Scott; Ruth, Jeffrey; Lanz, Otto; Ziglioli, Vincent

    2016-01-01

    An 11-year-old male German Shepherd dog presented for inappetence and weight loss. Physical examination and initial bloodwork revealed palpable abdominal masses, mild non-regenerative anemia, and thrombocytopenia. Survey radiography and abdominal ultrasonography confirmed the presence of bilateral abdominal masses and lymphadenopathy. Contrast-enhanced computed tomography (CT) was performed in order to further investigate the origin of the intraabdominal masses, confirming two enlarged cryptorchid testes, one of which had an associated CT “whirl sign.” Histopathology of the testes and lymph nodes revealed bilateral malignant Sertoli cell tumors and seminomas with lymph node metastasis of both neoplasms. The purpose of this case report is to discuss the benefits of CT in the diagnosis of cryptorchid testes and describe an additional organ that may display CT “whirl sign.” PMID:27200365

  6. Computed tomographic assessment of maxillary sinus wall thickness in edentulous patients.

    PubMed

    Yang, S-M; Park, S-I; Kye, S-B; Shin, S-Y

    2012-06-01

    Posterior maxillary region is considered to be the most challenging area for dental implant placement. Lateral window opening is the gold standard procedure for maxillary sinus augmentation in this area. The purpose of this study is to evaluate lateral wall thickness of the maxillary sinus for sinus augmentation using computed tomography (CT) in edentulous patients. Computed tomography images of 302 patients were analysed. Using the maxillary sinus floor as the reference point in edentulous regions, lateral wall thickness was measured on CT scans. After drawing a tangent line at the lowest point of the sinus floor, another perpendicular line to the tangent line was drawn at the same point of the sinus floor. Thickness of the lateral wall of the maxillary sinus was measured using 10DR implant software at 3 (R1), 10 (R2) and 15 mm (R3) from the sinus floor. The mean thickness of the lateral wall of the maxillary sinus from the first premolar to second molar was 1·69 ± 0·71, 1·50 ± 0·72, 1·77 ± 0·78 and 1·89 ± 0·85 mm, respectively. The thickness differed significantly at the R2 and R3 points. Women had thinner lateral walls at the R1 and R2 points at the premolars than did men. At the R2 and R3 points at the second premolar, the mean thickness of smokers was larger than that of non-smokers. There were no significant differences on age or reasons for tooth loss. The changes in the thickness of the lateral wall at different reference points were observed, and CT examinations may help make lateral window without membrane perforation. PMID:22471834

  7. Development of an electrical impedance computed tomographic two-phase flows analyzer. Final report

    SciTech Connect

    Ovacik, L.; Jones, O.C.

    1998-08-01

    This report summarizes the work on the research project on this cooperative program between DOE and Hitachi, Ltd. Major advances were made in the computational reconstruction of images from electrical excitation and response data with respect to existing capabilities reported in the literature. A demonstration is provided of the imaging of one or more circular objects within the measurement plane with demonstrated linear resolution of six parts in two hundred. At this point it can be said that accurate excitation and measurement of boundary voltages and currents appears adequate to obtain reasonable images of the real conductivity distribution within a body and the outlines of insulating targets suspended within a homogeneous conducting medium. The quality of images is heavily dependent on the theoretical and numerical implementation of imaging algorithms. The overall imaging system described has the potential of being both fast and cost effective in comparison with alternative methods. The methods developed use multiple plate-electrode excitation in conjunction with finite element block decomposition, preconditioned voltage conversion, layer approximation of the third dimension and post processing of boundary measurements to obtain optimal boundary excitations. Reasonably accurate imaging of single and multiple targets of differing size, location and separation is demonstrated and the resulting images are better than any others found in the literature. Recommendations for future effort include the improvement in computational algorithms with emphasis on internal conductivity shape functions and the use of adaptive development of quadrilateral (2-D) or tetrahedral or hexahedral (3-D) elements to coincide with large discrete zone boundaries in the fields, development of a truly binary model and completion of a fast imaging system. Further, the rudimentary methods shown herein for three-dimensional imaging need improving.

  8. Use of Coronary Computed Tomographic Angiography to Guide Management of Patients With Coronary Disease

    PubMed Central

    Williams, Michelle C.; Hunter, Amanda; Shah, Anoop S.V.; Assi, Valentina; Lewis, Stephanie; Smith, Joel; Berry, Colin; Boon, Nicholas A.; Clark, Elizabeth; Flather, Marcus; Forbes, John; McLean, Scott; Roditi, Giles; van Beek, Edwin J.R.; Timmis, Adam D.; Newby, David E.

    2016-01-01

    Background In a prospective, multicenter, randomized controlled trial, 4,146 patients were randomized to receive standard care or standard care plus coronary computed tomography angiography (CCTA). Objectives The purpose of this study was to explore the consequences of CCTA-assisted diagnosis on invasive coronary angiography, preventive treatments, and clinical outcomes. Methods In post hoc analyses, we assessed changes in invasive coronary angiography, preventive treatments, and clinical outcomes using national electronic health records. Results Despite similar overall rates (409 vs. 401; p = 0.451), invasive angiography was less likely to demonstrate normal coronary arteries (20 vs. 56; hazard ratios [HRs]: 0.39 [95% confidence interval (CI): 0.23 to 0.68]; p < 0.001) but more likely to show obstructive coronary artery disease (283 vs. 230; HR: 1.29 [95% CI: 1.08 to 1.55]; p = 0.005) in those allocated to CCTA. More preventive therapies (283 vs. 74; HR: 4.03 [95% CI: 3.12 to 5.20]; p < 0.001) were initiated after CCTA, with each drug commencing at a median of 48 to 52 days after clinic attendance. From the median time for preventive therapy initiation (50 days), fatal and nonfatal myocardial infarction was halved in patients allocated to CCTA compared with those assigned to standard care (17 vs. 34; HR: 0.50 [95% CI: 0.28 to 0.88]; p = 0.020). Cumulative 6-month costs were slightly higher with CCTA: difference $462 (95% CI: $303 to $621). Conclusions In patients with suspected angina due to coronary heart disease, CCTA leads to more appropriate use of invasive angiography and alterations in preventive therapies that were associated with a halving of fatal and non-fatal myocardial infarction. (Scottish COmputed Tomography of the HEART Trial [SCOT-HEART]; NCT01149590) PMID:27081014

  9. Computer analysis of arteriograms

    NASA Technical Reports Server (NTRS)

    Selzer, R. H.; Armstrong, J. H.; Beckenbach, E. B.; Blankenhorn, D. H.; Crawford, D. W.; Brooks, S. H.; Sanmarco, M. E.

    1977-01-01

    A computer system has been developed to quantify the degree of atherosclerosis in the human femoral artery. The analysis involves first scanning and digitizing angiographic film, then tracking the outline of the arterial image and finally computing the relative amount of roughness or irregularity in the vessel wall. The image processing system and method are described.

  10. Evidence for dysanapsis using computed tomographic imaging of the airways in older ex-smokers

    PubMed Central

    Guenette, Jordan A.; Yuan, Ren; Holy, Lukas; Mayo, John R.; McWilliams, Annette M.; Lam, Stephen; Coxson, Harvey O.

    2009-01-01

    We sought to determine the relationship between lung size and airway size in men and women of varying stature. We also asked if men and women matched for lung size would still have differences in airway size and if so where along the pulmonary airway tree would these differences exist. We used computed tomography to measure airway luminal areas of the large and central airways. We determined airway luminal areas in men (n = 25) and women (n = 25) who were matched for age, body mass index, smoking history, and pulmonary function and in a separate set of men (n = 10) and women (n = 11) who were matched for lung size. Men had greater values for the larger airways and many of the central airways. When male and female subjects were pooled there were significant associations between lung size and airway size. Within the male and female groups the magnitudes of these associations were decreased or nonsignificant. In males and females matched for lung size women had significantly smaller airway luminal areas. The larger conducting airways in females are significantly smaller than those of males even after controlling for lung size. PMID:19762522

  11. Computed tomographic imaging of dogs with primary laryngeal or tracheal airway obstruction.

    PubMed

    Stadler, Krystina; Hartman, Susan; Matheson, Jodi; O'Brien, Robert

    2011-01-01

    Seventeen dogs with clinical signs attributable to nonneoplastic obstruction of the larynx, trachea, or large bronchi underwent computed tomography (CT) imaging. In 16 of the 17 dogs, CT was performed without general anesthesia using a positioning device. Fifteen of these 16 dogs were imaged without sedation or general anesthesia. Three-dimensional (3D) internal rendering was performed on each image set based on lesion localization determined by routine image planes. Visual laryngeal examination, endoscopy, video fluoroscopy, and necropsy were used for achieving the cause of the upper airway obstruction. The CT and 3D internal rendering accurately indicated the presence and cause of upper airway obstruction in all dogs. CT findings indicative of laryngeal paralysis included failure to abduct the arytenoid cartilages, narrowed rima glottis, and air-filled laryngeal ventricles. Laryngeal collapse findings depended on the grade of collapse and included everted laryngeal saccules, collapse of the cuneiform processes and corniculate processes, and narrowed rima glottis. Trachea abnormalities included hypoplasia, stenosis, or collapse syndrome. The CT findings in tracheal hypoplasia consisted of a severely narrowed lumen throughout the entire length. Tracheal stenosis was represented by a circumferential decrease in tracheal lumen size limited to one region. Tracheal collapse syndrome was diagnosed by severe asymmetric narrowing. Lobar bronchi collapse appeared in CT images as a narrowed asymmetric lumen diameter. CT imaging of unanesthetized dogs with upper airway obstruction compares favorably with traditional definitive diagnostic methods. PMID:21447037

  12. Computed tomographic evaluation of cervical vertebral canal and spinal cord morphometry in normal dogs

    PubMed Central

    Seo, Eunjeong; Choi, Jihye; Choi, Mincheol

    2014-01-01

    The height, width, and cross-sectional area of the vertebral canal and spinal cord along with the area ratio of spinal cord to vertebral canal in the cervical vertebra were evaluated in images obtained using computed tomography (CT). Measurements were taken at the cranial, middle, and caudal point of each cervical vertebra in eight clinically normal small breed dogs (two shih tzu, two miniature schnauzers, and four mixed breed), 10 beagles, and four German shepherds. CT myelography facilitated the delineation of the epidural space, subarachnoid space, and spinal cord except at the caudal portion of the 7th cervical vertebra. The spinal cord had a tendency to have a clear ventral border in the middle portion of the vertebral canal and lateral borders near both end plates. The height, width, and area of the vertebral canal and spinal cord in the cervical vertebra were increased as the size of dog increased. However, the ratio of the spinal cord area to vertebral canal area in the small dogs was higher than that of the larger dogs. Results of the present study could provide basic and quantitative information for CT evaluation of pathologic lesions in the cervical vertebra and spinal cord. PMID:24136210

  13. Multidetector-row Computed Tomographic Angiography in the Planning of the Local Perforator Flaps

    PubMed Central

    Sliesarenko, Sergii V.

    2015-01-01

    Background: The perforator vessels are highly variable in number, localization types, hemodynamic specifications, and the anatomical interactions with other structures. For these reasons, the identification of the best perforator before the operation is very important for the choice of the main feed vessel and the design of the perforator flap. Methods: The authors retrospectively analyzed all cases in which multiple detector computed tomography (MDCT) with 3-dimensional (3D) image reconstruction was used in the preoperative planning in preparation for the reconstruction with local perforator flaps, which took place between July 2012 and December 2014 in the hospital. Results: A total of 24 people were examined and underwent operations with 26 reconstructions using local perforator flaps. All perforators, which were identified during the MDCT with 3D reconstruction examination, were located intraoperationally without any errors. Conclusions: The preoperative MDCT with 3D reconstruction investigations of the topographic anatomical specifics of the perforator vessel on which the formation of the flap feed pedicle is planned allow for the fast and precise identification of the perforation at the preoperative stage while minimizing the amount of injury caused to the perforator during the operation and decrease the operation time. PMID:26495229

  14. COMPUTED TOMOGRAPHIC AND ULTRASONOGRAPHIC CHARACTERISTICS OF CAVERNOUS TRANSFORMATION OF THE OBSTRUCTED PORTAL VEIN IN SMALL ANIMALS.

    PubMed

    Specchi, Swan; Pey, Pascaline; Ledda, Gianluca; Lustgarten, Meghann; Thrall, Donald; Bertolini, Giovanna

    2015-01-01

    In humans, the process of development of collateral vessels with hepatopetal flow around the portal vein in order to bypass an obstruction is called "cavernous transformation of the portal vein." The purpose of this retrospective, cross-sectional, multicentric study was to describe presumed cavernous transformation of the portal vein in small animals with portal vein obstruction using ultrasound and multidetector-row computed tomography (MDCT). Databases from three different institutions were searched for patients with an imaging diagnosis of cavernous transformation of the portal vein secondary to portal vein obstruction of any cause. Images were retrieved and reanalyzed. With MDCT-angiography, two main portoportal collateral pathways were identified: short tortuous portoportal veins around/inside the thrombus and long portoportal collaterals bypassing the site of portal obstruction. Three subtypes of the long collaterals, often coexisting, were identified. Branches of the hepatic artery where involved in collateral circulation in nine cases. Concomitant acquired portosystemic shunts were identified in six patients. With ultrasound, cavernous transformation of the portal vein was suspected in three dogs and one cat based on visualization of multiple and tortuous vascular structures corresponding to periportal collaterals. In conclusion, the current study provided descriptive MDCT and ultrasonographic characteristics of presumed cavernous transformation of the portal vein in a sample of small animals. Cavernous transformation of the portal vein could occur as a single condition or could be concurrent with acquired portosystemic shunts. PMID:25877678

  15. Gross, Histologic, and Computed Tomographic Anatomy of the Lacrimal System of Snakes

    PubMed Central

    Souza, Nicole M.; Maggs, David J.; Park, Shin Ae; Puchalski, Sarah; Reilly, Christopher M.; Paul-Murphy, Joanne; Murphy, Christopher J.

    2014-01-01

    Objective To describe the lacrimal system of snakes using contrast micro-computed tomography (micro-CT) with 3-dimensional reconstruction, fluorescein passage (“Jones”) testing, histology, and gross dissection. Animals studied One Royal Python and 19 snake cadavers representing 10 species. Procedures Direct observation following injection of fluorescein into the subspectacular space, micro-CT following injection of 3 contrast agents into the subspectacular space, gross dissection following injection of latex into the subspectacular space, and histopathology. Results Injection of fluorescein confirmed patency but not course of the lacrimal duct. Barium enabled clear visualization of the lacrimal duct whereas two iodinated contrast agents proved inadequate. Collectively, micro-CT, anatomic dissections, and histology suggest tears are produced by a single, large, serous, retrobulbar gland, released into the subspectacular space via several ductules, and drained through a single punctum originating in the ventronasal subspectacular space and the lacrimal duct taking one of 3 routes of variable tortuosity before opening into the oral cavity in close association with the opening of the duct of the vomeronasal organ. Conclusions The ophidian lacrimal duct has a generally tortuous course and the details of its anatomy is species variable. The tortuous course of the duct likely predisposes snakes to duct occlusion and must be considered when planning medical and surgical interventions in snakes with pseudobuphthalmos and subspectacular abscessation. PMID:24862081

  16. Computed tomographic arthrography of the intercarpal ligaments of the equine carpus.

    PubMed

    Gray, Sarah N; Puchalski, Sarah M; Galuppo, Larry D

    2013-01-01

    Injuries of the intercarpal ligaments are an important cause of lameness in performance horses. The purpose of this prospective cadaver study was to determine whether computed tomography (CT) arthrography would be a feasible method for visualizing and characterizing intercarpal ligaments in the horse. One cadaver limb from each of eight nonlame horses was collected immediately after euthanasia. For each limb, overlapping 2.0 mm CT images were acquired before and after injection of iodinated contrast medium into the antebrachiocarpal joint, middle carpal joint, and carpal sheath. Spin echo magnetic resonance imaging (MRI) sequences were acquired in three planes using a 1.5 Tesla MRI scanner in three limbs. Following MRI, colored resin was injected into the synovial structures of these three limbs, limbs were frozen, and anatomic sections were obtained in three planes. Findings from CT arthrograms were compared to findings from precontrast CT, MRI, anatomic slices, and arthroscopy. Medial and lateral palmar intercarpal ligaments, radiocarpal and transverse intercarpal ligaments, and palmar carpal ligament were visible in CT arthrograms of all limbs. The proximal and distal entheses of all ligaments were readily identifiable. Findings indicated that CT arthrography is feasible for visualizing intercarpal ligaments and may be a useful adjunct imaging technique for diagnosing lameness due to suspected carpal ligament injury in horses. PMID:23489249

  17. Computed tomographic findings in dogs and cats with temporomandibular joint disorders: 58 cases (2006–2011)

    PubMed Central

    Arzi, Boaz; Cissell, Derek D.; Verstraete, Frank J. M.; Kass, Philip H.; DuRaine, Grayson D.; Athanasiou, Kyriacos A.

    2013-01-01

    Objective To describe CT findings in dogs and cats with temporomandibular joint (TMJ) disorders. Design Retrospective case-series. Animals 41 dogs and 17 cats. Procedures Medical records and CT images of the skull were reviewed for dogs and cats that were examined at a dentistry and oral surgery specialty practice between 2006 and 2011. Results Of 142 dogs and 42 cats evaluated, 41 dogs and 17 cats had CT findings consistent with a TMJ disorder. In dogs, the most common TMJ disorder was osteoarthritis; however, in most cases, there were other TMJ disorders present in addition to osteoarthritis. Osteoarthritis was more frequently identified at the medial aspect rather than the lateral aspect of the TMJ, whereas the frequency of osteoarthritic involvement of the dorsal and ventral compartments did not differ significantly. In cats, fractures were the most common TMJ disorder, followed by osteoarthritis. Clinical signs were observed in all dogs and cats with TMJ fractures, dysplasia, ankylosis, luxation, and tumors; however, only 4 of 15 dogs and 2 of 4 cats with osteoarthritis alone had clinical signs. Conclusions and Clinical Relevance Results indicated that TMJ disorders are frequently present in combination. Osteoarthritis was the most common TMJ disorder in dogs and the second most common TMJ disorder in cats. Computed tomography should be considered as a tool for the diagnosis of TMJ disorders in dogs and cats with suspected orofacial disorders and pain. PMID:23234284

  18. COMPUTED TOMOGRAPHIC ANATOMY AND CHARACTERISTICS OF RESPIRATORY ASPERGILLOSIS IN JUVENILE WHOOPING CRANES

    PubMed Central

    Kelley, Cristin; Pinkerton, Marie E.; Hartup, Barry K.

    2015-01-01

    Respiratory diseases are a leading cause of morbidity and mortality in captivity reared, endangered whooping cranes (Grus americana). Objectives of this retrospective, case series, cross‐sectional study were to describe computed tomography (CT) respiratory anatomy in a juvenile whooping crane without respiratory disease, compare CT characteristics with gross pathologic characteristics in a group of juvenile whooping cranes with respiratory aspergillosis, and test associations between the number of CT tracheal bends and bird sex and age. A total of 10 juvenile whooping cranes (one control, nine affected) were included. Seven affected cranes had CT characteristics of unilateral extrapulmonary bronchial occlusion or wall thickening, and seven cranes had luminal occlusion of the intrapulmonary primary or secondary bronchi. Air sac membrane thickening was observed in three cranes in the cranial and caudal thoracic air sacs, and air sac diverticulum opacification was observed in four cranes. Necropsy lesions consisted of severe, subacute to chronic, focally extensive granulomatous pathology of the trachea, primary bronchi, lungs, or air sacs. No false positive CT scan results were documented. Seven instances of false negative CT scan results occurred; six of these consisted of subtle, mild air sacculitis including membrane opacification or thickening, or the presence of small plaques found at necropsy. The number of CT tracheal bends was associated with bird age but not sex. Findings supported the use of CT as a diagnostic test for avian species with respiratory disease and tracheal coiling or elongated tracheae where endoscopic evaluation is impractical. PMID:26592357

  19. COMPUTED TOMOGRAPHIC ANATOMY AND CHARACTERISTICS OF RESPIRATORY ASPERGILLOSIS IN JUVENILE WHOOPING CRANES.

    PubMed

    Schwarz, Tobias; Kelley, Cristin; Pinkerton, Marie E; Hartup, Barry K

    2016-01-01

    Respiratory diseases are a leading cause of morbidity and mortality in captivity reared, endangered whooping cranes (Grus americana). Objectives of this retrospective, case series, cross-sectional study were to describe computed tomography (CT) respiratory anatomy in a juvenile whooping crane without respiratory disease, compare CT characteristics with gross pathologic characteristics in a group of juvenile whooping cranes with respiratory aspergillosis, and test associations between the number of CT tracheal bends and bird sex and age. A total of 10 juvenile whooping cranes (one control, nine affected) were included. Seven affected cranes had CT characteristics of unilateral extrapulmonary bronchial occlusion or wall thickening, and seven cranes had luminal occlusion of the intrapulmonary primary or secondary bronchi. Air sac membrane thickening was observed in three cranes in the cranial and caudal thoracic air sacs, and air sac diverticulum opacification was observed in four cranes. Necropsy lesions consisted of severe, subacute to chronic, focally extensive granulomatous pathology of the trachea, primary bronchi, lungs, or air sacs. No false positive CT scan results were documented. Seven instances of false negative CT scan results occurred; six of these consisted of subtle, mild air sacculitis including membrane opacification or thickening, or the presence of small plaques found at necropsy. The number of CT tracheal bends was associated with bird age but not sex. Findings supported the use of CT as a diagnostic test for avian species with respiratory disease and tracheal coiling or elongated tracheae where endoscopic evaluation is impractical. PMID:26592357

  20. X-ray Computed Tomographic Investigation of the Porosity and Morphology of Plasma Electrolytic Oxidation Coatings.

    PubMed

    Zhang, Xun; Aliasghari, Sepideh; Němcová, Aneta; Burnett, Timothy L; Kuběna, Ivo; Šmíd, Miroslav; Thompson, George E; Skeldon, Peter; Withers, Philip J

    2016-04-01

    Plasma electrolytic oxidation (PEO) is of increasing interest for the formation of ceramic coatings on metals for applications that require diverse coating properties, such as wear and corrosion resistance, low thermal conductivity, and biocompatibility. Porosity in the coatings can have an important impact on the coating performance. However, the quantification of the porosity in coatings can be difficult due to the wide range of pore sizes and the complexity of the coating morphology. In this work, a PEO coating formed on titanium is examined using high resolution X-ray computed tomography (X-ray CT). The observations are validated by comparisons of surface views and cross-sectional views of specific coating features obtained using X-ray CT and scanning electron microscopy. The X-ray CT technique is shown to be capable of resolving pores with volumes of at least 6 μm(3). Furthermore, the shapes of large pores are revealed and a correlation is demonstrated between the locations of the pores, nodules on the coating surface, and depressions in the titanium substrate. The locations and morphologies of the pores, which constitute 5.7% of the coating volume, indicate that they are generated by release of oxygen gas from the molten coating. PMID:26974706

  1. Abdominal computed tomographic scan-merits and demerits over ultrasonography: evaluation of 70 cases.

    PubMed

    Obajimi, M O; Ogunseyinde, A O; Agunloye, A M

    2002-06-01

    Computed tomography (CT) and Ultrasonography (USS) are commonly used to ascertain the cause of abdominal symptoms. In a retrospective study of 70 Nigerian patients who had abdominal ultrasonography prior to abdominal CT scans, the most frequent clinical feature was abdominal pain, which was reported in 20.8% of the patients. The prevalent ultrasonographic finding was hepatomegaly (12.2%) while bowel displacement was the most frequently reported CT finding (18.3%). There was no correlation between USS and CT findings in 11 patients (15.7%). There was some agreement in the findings of both tests in 75.7% of cases. Additional findings were noted in 38 (54.3%) of the latter group of patients on CT scans. Hundred percent agreement was reported in both imaging techniques in 5 radiological findings namely: dilated gall bladder, renal cysts, ascites, adrenal mass and utero-cervical mass. These findings suggest a high yield of diagnostic accuracy from abdominal sonography and increased diagnostic details provided by CT imaging. Our overall impression is that the diagnostic information provided by the two techniques are complimentary. PMID:12518911

  2. Computed Tomographic presentation of obstructive jejunal adenocarcinoma associated with celiac disease and incomplete intestinal malrotation

    PubMed Central

    Ines, Marzouk Moussa; Ennaifer, Rym; Omrani, Sahir; Ahlem, Lahmar Boufaroua; Ouji, Rym; Hendaoui, Lotfi

    2015-01-01

    Introduction Small bowel adenocarcinoma is a rare entity most frequently observed with celiac disease. This is the first case report on the association of celiac disease, small bowel adenocarcinoma and intestinal malrotation. Case report A 40 year-old male patient diagnosed with celiac disease since the age of 5 years complained of epigastric pain and vomiting for three days. Computed tomography (CT) showed a significant gastroduodenal dilatation with thickened intestinal wall proximal to the duodenojejunal flexure. The lumen contained a food bezoar in the center. The duodenojejunal angle was abnormally on the right side of the abdomen and the superior mesenteric vein was anterior to the superior mesenteric artery. Endoscopy after aspiration found a hemi-circumferential and irregular mass which bled at the contact of fibroscope. Biopsies showed an adenocarcinoma and small bowel resection was performed. Discussion Celiac disease is associated with a high risk of small bowel cancer. The association of incomplete intestinal malrotation, duodenojejunal flexure tumor and celiac disease made the surgery challenging. Conclusion Patients with celiac disease should be carefully monitored and endoscopic or radiologic investigations should be carried out in patients with any doubtful symptoms. PMID:26670410

  3. Utility of an advanced digital electronic stethoscope in the diagnosis of coronary artery disease compared with coronary computed tomographic angiography.

    PubMed

    Makaryus, Amgad N; Makaryus, John N; Figgatt, Alan; Mulholland, Dan; Kushner, Harvey; Semmlow, John L; Mieres, Jennifer; Taylor, Allen J

    2013-03-15

    The detection of coronary artery microbruits, subaudible bruits too faint to be heard through standard auscultation, may provide an alternative means to diagnose coronary artery disease (CAD). The aim of this study was to test the accuracy of a novel digital electronic stethoscope, the Cardiac Sonospectrographic Analyzer (CSA; SonoMedica model 3.0, SonoMedica, Inc., Vienna, Virginia, United States Food and Drug Administration 510[k] cleared) to diagnose CAD compared to gold-standard diagnosis using cardiac computed tomographic (CT) angiography. In this blinded, single-site study, adults previously referred for CT imaging were selected. Patients underwent CT and CSA evaluations. CSA exams entailed recording heart sounds at 9 positions on the chest for 40 seconds at each position. An algorithm then processed these data to generate a microbruit score. The CT scans were read blinded to patients' microbruit scores. Sensitivity and specificity of the CSA in detecting CAD compared to CT imaging were estimated using standard receiver-operating characteristic curves calculated from logistic regression models. A total of 161 patients, aged 57 ± 13 years (range 22 to 85), 53% with hypertension and 40% with obesity (body mass index ≥30 kg/m(2)), completed the protocol and had evaluable CT and CSA examinations. The overall sensitivity of the CSA to identify >50% stenosis in any major epicardial coronary artery as determined by CT imaging was 89.5% (p <0.0001). Gender-specific models based on smaller sample sizes had slightly poorer results and lower specificity among men with heavy chest hair. In conclusion, the CSA showed high sensitivity and specificity for the detection of significant early CAD in an outpatient setting and represents a new noninvasive device for detecting abnormal coronary blood flow as occurs in CAD. PMID:23290309

  4. Original Protocol Using Computed Tomographic Angiography for Diagnosis of Brain Death: A Better Alternative to Standard Two-Phase Technique?

    PubMed

    Sawicki, Marcin; Sołek-Pastuszka, Joanna; Jurczyk, Krzysztof; Skrzywanek, Piotr; Guziński, Maciej; Czajkowski, Zenon; Mańko, Witold; Burzyńska, Małgorzata; Safranow, Krzysztof; Poncyljusz, Wojciech; Walecka, Anna; Rowiński, Olgierd; Walecki, Jerzy; Bohatyrewicz, Romuald

    2015-01-01

    BACKGROUND The application of computed tomographic angiography (CTA) for the diagnosis of brain death (BD) is limited because of the low sensitivity of the commonly used two-phase method consisting of assessing arterial and venous opacification at the 60th second after contrast injection. The hypothesis was that a reduction in the scanning delay might increase the sensitivity of the test. Therefore, an original technique using CTA was introduced and compared with catheter angiography as a reference. MATERIAL AND METHODS In a prospective multicenter trial, 84 clinically brain-dead patients were examined using CTA and catheter angiography. The sensitivities of original CTA technique, involving an arterial assessment at the 25th second and a venous assessment at the 40th second, and the standard CTA, involving an arterial and venous assessment at the 60th second, were compared to catheter angiography. RESULTS Catheter angiography results were consistent with the clinical diagnosis of BD in all cases. In comparison to catheter angiography, the sensitivity of original CTA technique was 0.93 (95%CI, 0.85-0.97; p<0.001) and 0.57 (95%CI, 0.46-0.68; p<0.001) for the standard protocol. The differences were statistically significant (p=0.03 for original CTA and p<0.001 for standard CTA). Decompressive craniectomy predisposes to a false-negative CTA result with a relative risk of 3.29 (95% CI, 1.76-5.81; p<0.001). CONCLUSIONS Our original technique using CTA for the assessment of the cerebral arteries during the arterial phase and the deep cerebral veins with a delay of 15 seconds is a highly sensitive test for the diagnosis of BD. This method may be a better alternative to the commonly used technique. PMID:26250464

  5. ASSOCIATION BETWEEN COMPUTED TOMOGRAPHIC CHARACTERISTICS AND FRACTURES FOLLOWING STEREOTACTIC RADIOSURGERY IN DOGS WITH APPENDICULAR OSTEOSARCOMA.

    PubMed

    Kubicek, Lyndsay; Vanderhart, Daniel; Wirth, Kimberly; An, Qi; Chang, Myron; Farese, James; Bova, Francis; Sudhyadhom, Atchar; Kow, Kelvin; Bacon, Nicholas J; Milner, Rowan

    2016-05-01

    The objective of this observational, descriptive, retrospective study was to report CT characteristics associated with fractures following stereotactic radiosurgery in canine patients with appendicular osteosarcoma. Medical records (1999 and 2012) of dogs that had a diagnosis of appendicular osteosarcoma and undergone stereotactic radiosurgery were reviewed. Dogs were included in the study if they had undergone stereotactic radiosurgery for an aggressive bone lesion with follow-up information regarding fracture status, toxicity, and date and cause of death. Computed tomography details, staging, chemotherapy, toxicity, fracture status and survival data were recorded. Overall median survival time (MST) and fracture rates of treated dogs were calculated. CT characteristics were evaluated for association with time to fracture. Forty-six dogs met inclusion criteria. The median overall survival time was 9.7 months (95% CI: 6.9-14.3 months). The fracture-free rates at 3, 6, and 9 months were 73%, 44%, and 38% (95% CI: 60-86%, 29-60%, and 22-54%), respectively. The region of bone affected was significantly associated with time to fracture. The median time to fracture was 4.2 months in dogs with subchondral bone involvement and 16.3 months in dogs without subchondral bone involvement (P-value = 0.027, log-rank test). Acute and late skin effects were present in 58% and 16% of patients, respectively. Findings demonstrated a need for improved patient selection for this procedure, which can be aided by CT-based prognostic factors to predict the likelihood of fracture. PMID:26916056

  6. Shaping ability of rotatory or reciprocating instruments in curved canals: a micro-computed tomographic study.

    PubMed

    Jardine, Alexander Pompermayer; Rosa, Ricardo Abreu da; Santini, Manuela Favarin; Zaccara, Ivana Maria; Só, Marcus Vinicius Reis; Kopper, Patrícia Maria Poli

    2016-06-14

    This study aimed to compare apical transportation, centering ratio, and working time during root canal preparation with Wizard Navigator (WN), WaveOne (WO), or ProTaper Universal (PT) and to describe deformation and fracture of these instruments. Thirty-six mesiobuccal roots from maxillary molars were micro-computed tomography (micro-CT) scanned and then sorted into three groups (n = 12): Wizard Navigator (WN), WaveOne (WO), and ProTaper Universal (PT). The root canals were prepared using WN, WO, or PT; the time of each canal preparation was timed; and the specimens were micro-CT re-scanned. The instruments were submitted to scanning electron microscopy (SEM) before and after their use. The data on canal transportation at 1, 2, 3, 4 and 5 mm and preparation time were analyzed by the Kruskal-Wallis test, followed by the Mann-Whitney U test. The centering ratio was analyzed by ANOVA, followed by Tukey's test. Both instrument deformation and fracture were described. Apical transportation was similar among groups at 1, 2, 3 and 4 mm. The WO group showed higher canal transportation at 5mm than the other groups (p = 0.03). There was no significant difference in centering ratio among the groups. Preparation time in the WO group was significantly lower than in the other groups (p = 0.004). Small differences were observed in the surface area of all instruments. The WN, WO, and PT groups had a similar centering ratio without procedural errors or significant structural changes. At 5 mm from the apex, the WO group showed the largest canal transportation toward the furcation and root canal preparation was faster than in the WN and PT groups. PMID:27305517

  7. Coronary computed tomographic angiography: current role in the diagnosis and management of coronary artery disease

    PubMed Central

    Bowman, Andrew W.; Kantor, Birgit; Gerber, Thomas C.

    2009-01-01

    Advances in computed tomography (CT) technology allow images to be obtained with high spatial and temporal resolution. These features now permit noninvasive coronary CT angiography (CCTA). Many studies addressing proof of concept, feasibility, and clinical robustness have been published since CCTA was first described. More recently, the scientific evaluation of CCTA has rightly focused less on technical aspects and more on multicenter trials of the diagnostic value of CCTA and on head-to-head comparisons with other noninvasive modalities for the detection of coronary artery disease (CAD), such as stress myocardial perfusion imaging (MPI) with radionuclides. Recent peer-reviewed publications that compare CCTA to invasive, selective coronary angiography (SCA) or MPI, or that address radiation protection issues related to CCTA, were reviewed and summarized. Overall, there is high agreement between CCTA and both SCA and MPI for the presence of CAD. However, CCTA can over- or underestimate the severity of CAD compared to SCA as a reference standard. Initial studies that compared CCTA to MPI found their accuracies for determining the presence of high-grade luminal obstructions comparable. Limitations of CCTA include inability to reliably assess the coronary artery lumen dimensions in patients with large amounts of coronary artery calcium, artifacts caused by coronary and respiratory motion, and the need for ionizing radiation and intravenous administration of iodinated contrast material. Various dose reduction methods for CCTA now exist that may substantially lower patient dose to levels less than those of SCA or MPI. Although current expert consensus does not call for CCTA to be a first-line test for CAD, particularly for screening in asymptomatic individuals, current data suggest a promising role in the evaluation of symptomatic patients for possible CAD. PMID:19694220

  8. EFFECTS OF FLUID AND COMPUTED TOMOGRAPHIC TECHNICAL FACTORS ON CONSPICUITY OF CANINE AND FELINE NASAL TURBINATES

    PubMed Central

    Uosyte, Raimonda; Shaw, Darren J; Gunn-Moore, Danielle A; Fraga-Manteiga, Eduardo; Schwarz, Tobias

    2015-01-01

    Turbinate destruction is an important diagnostic criterion in canine and feline nasal computed tomography (CT). However decreased turbinate visibility may also be caused by technical CT settings and nasal fluid. The purpose of this experimental, crossover study was to determine whether fluid reduces conspicuity of canine and feline nasal turbinates in CT and if so, whether CT settings can maximize conspicuity. Three canine and three feline cadaver heads were used. Nasal slabs were CT-scanned before and after submerging them in a water bath; using sequential, helical, and ultrahigh resolution modes; with images in low, medium, and high frequency image reconstruction kernels; and with application of additional posterior fossa optimization and high contrast enhancing filters. Visible turbinate length was measured by a single observer using manual tracing. Nasal density heterogeneity was measured using the standard deviation (SD) of mean nasal density from a region of interest in each nasal cavity. Linear mixed-effect models using the R package ‘nlme’, multivariable models and standard post hoc Tukey pair-wise comparisons were performed to investigate the effect of several variables (nasal content, scanning mode, image reconstruction kernel, application of post reconstruction filters) on measured visible total turbinate length and SD of mean nasal density. All canine and feline water-filled nasal slabs showed significantly decreased visibility of nasal turbinates (P < 0.001). High frequency kernels provided the best turbinate visibility and highest SD of aerated nasal slabs, whereas medium frequency kernels were optimal for water-filled nasal slabs. Scanning mode and filter application had no effect on turbinate visibility. PMID:25867935

  9. The VetMousetrap: a device for computed tomographic imaging of the thorax of awake cats.

    PubMed

    Oliveira, Cintia R; Ranallo, Frank N; Pijanowski, Gerald J; Mitchell, Mark A; O'Brien, Mauria A; McMichael, Maureen; Hartman, Susan K; Matheson, Jodi S; O'Brien, Robert T

    2011-01-01

    The VetMousetrap, a novel device that allows computed tomography (CT) of awake cats and provides a clinically supportive environment, is described. Ten normal cats were used to test the device for ambient internal oxygen, carbon dioxide levels, and temperature. Twenty-two awake normal cats were imaged using a 16-multislice helical CT unit to evaluate dose-equivalent protocols. Two different X-ray tube potentials (kV), 80 and 120, and two different helical pitches, 0.562 and 1.75, were evaluated. The signal intensity of the pulmonary parenchyma (SIlung), signal intensity of background (SIbackgr), contrast, noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were calculated. Three evaluators ranked the images for sharpness of liver margins, motion, helical, and windmill artifacts. CT was successfully completed in 20 of 22 cats. No artifacts directly related to the device were detected. Overall, 75 of 80 (94%) examinations were judged to have absent or minimal motion artifact. A statistically significant difference was found for SNR (P = 0.001) and CNR (P = 0.001) between all protocols. The higher pitch protocols had significantly lower noise and higher SNR and CNR, lower motion artifact but greater helical artifacts. A protocol using 80 kV, 130 mA, 0.5s, and 0.562 pitch with 1.25mm slice thickness, and 0.625 mm slice reconstruction interval is recommended. The VetMousetrap appears to provide the opportunity for diagnostic CT imaging of the thorax of awake cats. PMID:21322386

  10. Computed tomographic features of feline sino-nasal and sino-orbital aspergillosis.

    PubMed

    Barrs, V R; Beatty, J A; Dhand, N K; Talbot, J J; Bell, E; Abraham, L A; Chapman, P; Bennett, S; van Doorn, T; Makara, M

    2014-08-01

    Feline upper respiratory tract aspergillosis (URTA) occurs as two distinct anatomical forms, namely, sino-nasal aspergillosis (SNA) and sino-orbital aspergillosis (SOA). An emerging pathogen, Aspergillus felis, is frequently involved. The pathogenesis of URTA, in particular the relationship between the infecting isolate and outcome, is poorly understood. In this study, computed tomography was used to investigate the route of fungal infection and extension in 16 cases (SNA n = 7, SOA n = 9) where the infecting isolate had been identified by molecular testing. All cases had nasal cavity involvement except for one cat with SNA that had unilateral frontal sinus changes. There was a strong association between the infecting species and anatomic form (P = 0.005). A. fumigatus infections remained within the sino-nasal cavity, while cryptic species infections were associated with orbital and paranasal soft-tissue involvement and with orbital lysis. Cryptic species were further associated with a mass in the nasal cavity, paranasal sinuses or nasopharynx. Orbital masses showed heterogeneous contrast enhancement, with central coalescing hypoattenuating foci and peripheral rim enhancement. Severe, cavitated turbinate lysis, typical of canine SNA, was present only in cats with SNA. These findings support the hypothesis that the nasal cavity is the portal of entry for fungal spores in feline URTA and that the route of extension to involve the orbit is via direct naso-orbital communication from bone lysis. Additionally, a pathogenic role for A. wyomingensis and a sinolith in a cat with A. udagawae infection are reported for the first time. PMID:24685469

  11. Comparison of computed tomographic findings in pulmonary mucormycosis and invasive pulmonary aspergillosis.

    PubMed

    Jung, J; Kim, M Y; Lee, H J; Park, Y S; Lee, S-O; Choi, S-H; Kim, Y S; Woo, J H; Kim, S-H

    2015-07-01

    Because there are no available molecular markers for pulmonary mucormycosis (PM), which has low culture sensitivity, early diagnosis and treatment rely heavily on imaging modes such as computed tomography (CT). However, there are limited data comparing CT findings for PM with those for invasive pulmonary aspergillosis (IPA). Adult patients who met the modified criteria for proven and probable PM (over an 11-year period) and IPA (over a 6-year period, owing to the availability of the galactomannan assay) according to the modified European Organization for Research and Treatment of Cancer/Mycosis Study Group definitions were retrospectively enrolled. IPA cases were selected at a 1 : 4 (PM/IPA) ratio. Thoracic CT scans were reviewed by two experienced radiologists blinded to the patients' demographics and clinical outcomes. A total of 24 patients with PM, including 20 (83%) with proven PM and four (17%) with probable PM, and 96 patients with IPA, including 12 (13%) with proven IPA and 84 (87%) with probable IPA, were eventually analysed. The reverse halo sign was more common in patients with PM (54%) than in those with IPA (6%, p < 0.001), whereas some airway-invasive features, such as clusters of centrilobular nodules, peribronchial consolidations, and bronchial wall thickening, were more common in patients with IPA (IPA 52% vs. PM 29%, p 0.04; IPA 49% vs. PM 21%, p 0.01; IPA 34% vs. PM 4%, p 0.003, respectively). The reverse halo sign was more common, and airway-invasive features were less common, in patients with PM than in those with IPA. These findings may help physicians to initiate Zygomycetes-active antifungal treatment earlier. PMID:25882362

  12. Setup Variations in Radiotherapy of Esophageal Cancer: Evaluation by Daily Megavoltage Computed Tomographic Localization

    SciTech Connect

    Chen, Y.-J. . E-mail: yichen@coh.org; Han Chunhui; Liu An; Schultheiss, Timothy E.; Kernstine, Kemp H.; Shibata, Stephen; Vora, Nayana L.; Pezner, Richard D.; Wong, Jeffrey Y.C.

    2007-08-01

    Purpose: To use pretreatment megavoltage computed tomography (MVCT) scans to evaluate setup variations in anterior-posterior (AP), lateral, and superior-inferior (SI) directions and rotational variations, including pitch, roll, and yaw, for esophageal cancer patients treated with helical tomotherapy. Methods and Materials: Ten patients with locally advanced esophageal cancer treated by combined chemoradiation using helical tomotherapy were selected. After patients were positioned using their skin tattoos/marks, MVCT scans were performed before every treatment and automatically registered to planning kilovoltage CT scans according to bony landmarks. Image registration data were used to adjust patient setups before treatment. A total of 250 MVCT scans were analyzed. Correlations between setup variations and body habitus, including height, weight, relative weight change, body surface area, and patient age, were evaluated. Results: The standard deviations for systematic setup corrections in AP, lateral, and SI directions and pitch, roll, and yaw rotations were 1.5, 3.7, and 4.8 mm and 0.5 deg., 1.2 deg., and 0.8 deg., respectively. The appropriate averages of random setup variations in AP, lateral, and SI directions and pitch, roll, and yaw rotations were 2.9, 5.2, and 4.4 mm, and 1.0 deg., 1.2 deg., and 1.1 deg., respectively. Setup variations were stable throughout the entire course of radiotherapy in all three translational and three rotational displacements, with little change in magnitude. No significant correlations were found between setup variations and body habitus variables. Conclusions: Daily MVCT scans before each treatment can effectively detect setup errors and thereby reduce planning target volume (PTV) margins. This will reduce radiation dose to critical organs and may translate into lower treatment-related toxicities.

  13. THE EFFECT OF ANGLE SLICE ACQUISITION ON COMPUTED TOMOGRAPHIC CERVICAL VERTEBRAL COLUMN MORPHOMETRY IN GREAT DANES.

    PubMed

    Jurkoshek, Amanda M; da Costa, Ronaldo C; Martin-Vaquero, Paula

    2015-01-01

    Computed tomography (CT) scans can be acquired with the transverse images aligned either parallel to the endplates or perpendicular to the vertebral canal. The purpose of this prospective cross-sectional study was to determine the effect of angle acquisition on CT morphometric evaluation of the cervical vertebral column of Great Danes with and without cervical spondylomyelopathy. Twenty-eight Great Danes (13 normal, 15 affected) were sampled. For each dog, a set of CT images was acquired with the transverse slices aligned parallel to the endplates and another one with the transverse images aligned perpendicular to the vertebral canal. For each different set, transverse slices from the cranial, middle, and caudal aspects of the individual vertebral bodies C2-C7 were measured. Height, width, transverse area, right dorsal to left ventral height (RDLV), and left dorsal to right ventral height (LDRV) were recorded by a single observer at each location. For both affected and control dogs, significant differences between the measurements obtained from the two sets of transverse images were found only at the cranial aspect of the vertebrae (P = 0.005, P < 0.001, P < 0.001, P = 0.005, and P = 0.010 for height, width, area, RDLV, and LDRV, respectively). Measurements for the middle and caudal aspects did not differ. The funnel-shape morphology of the cervical vertebral foramina in Great Danes with stenosis of their cranial aspect may be responsible for the significant differences found. Considering that the morphometric parameters were significantly affected by CT slice angle in the current study, authors recommend that a standardized scanning protocol be followed when morphometric evaluations using CT are planned. PMID:25872964

  14. EFFECTS OF FLUID AND COMPUTED TOMOGRAPHIC TECHNICAL FACTORS ON CONSPICUITY OF CANINE AND FELINE NASAL TURBINATES.

    PubMed

    Uosyte, Raimonda; Shaw, Darren J; Gunn-Moore, Danielle A; Fraga-Manteiga, Eduardo; Schwarz, Tobias

    2015-01-01

    Turbinate destruction is an important diagnostic criterion in canine and feline nasal computed tomography (CT). However decreased turbinate visibility may also be caused by technical CT settings and nasal fluid. The purpose of this experimental, crossover study was to determine whether fluid reduces conspicuity of canine and feline nasal turbinates in CT and if so, whether CT settings can maximize conspicuity. Three canine and three feline cadaver heads were used. Nasal slabs were CT-scanned before and after submerging them in a water bath; using sequential, helical, and ultrahigh resolution modes; with images in low, medium, and high frequency image reconstruction kernels; and with application of additional posterior fossa optimization and high contrast enhancing filters. Visible turbinate length was measured by a single observer using manual tracing. Nasal density heterogeneity was measured using the standard deviation (SD) of mean nasal density from a region of interest in each nasal cavity. Linear mixed-effect models using the R package 'nlme', multivariable models and standard post hoc Tukey pair-wise comparisons were performed to investigate the effect of several variables (nasal content, scanning mode, image reconstruction kernel, application of post reconstruction filters) on measured visible total turbinate length and SD of mean nasal density. All canine and feline water-filled nasal slabs showed significantly decreased visibility of nasal turbinates (P < 0.001). High frequency kernels provided the best turbinate visibility and highest SD of aerated nasal slabs, whereas medium frequency kernels were optimal for water-filled nasal slabs. Scanning mode and filter application had no effect on turbinate visibility. PMID:25867935

  15. 3D printing of preclinical X-ray computed tomographic data sets.

    PubMed

    Doney, Evan; Krumdick, Lauren A; Diener, Justin M; Wathen, Connor A; Chapman, Sarah E; Stamile, Brian; Scott, Jeremiah E; Ravosa, Matthew J; Van Avermaete, Tony; Leevy, W Matthew

    2013-01-01

    Three-dimensional printing allows for the production of highly detailed objects through a process known as additive manufacturing. Traditional, mold-injection methods to create models or parts have several limitations, the most important of which is a difficulty in making highly complex products in a timely, cost-effective manner.(1) However, gradual improvements in three-dimensional printing technology have resulted in both high-end and economy instruments that are now available for the facile production of customized models.(2) These printers have the ability to extrude high-resolution objects with enough detail to accurately represent in vivo images generated from a preclinical X-ray CT scanner. With proper data collection, surface rendering, and stereolithographic editing, it is now possible and inexpensive to rapidly produce detailed skeletal and soft tissue structures from X-ray CT data. Even in the early stages of development, the anatomical models produced by three-dimensional printing appeal to both educators and researchers who can utilize the technology to improve visualization proficiency. (3, 4) The real benefits of this method result from the tangible experience a researcher can have with data that cannot be adequately conveyed through a computer screen. The translation of pre-clinical 3D data to a physical object that is an exact copy of the test subject is a powerful tool for visualization and communication, especially for relating imaging research to students, or those in other fields. Here, we provide a detailed method for printing plastic models of bone and organ structures derived from X-ray CT scans utilizing an Albira X-ray CT system in conjunction with PMOD, ImageJ, Meshlab, Netfabb, and ReplicatorG software packages. PMID:23542702

  16. COMPUTED TOMOGRAPHIC APPEARANCE OF THE TEMPOROMANDIBULAR JOINT IN 1018 ASYMPTOMATIC HORSES: A MULTI-INSTITUTION STUDY.

    PubMed

    Carmalt, James L; Kneissl, Sibylle; Rawlinson, Jennifer E; Zwick, Timo; Zekas, Lisa; Ohlerth, Stefanie; Bienert-Zeit, Astrid

    2016-05-01

    Published descriptions of nonseptic arthritis of the equine temporomandibular joint (TMJ) are rare and large studies investigating variations in the TMJ for asymptomatic horses are lacking. The objectives of this cross-sectional, retrospective, multi-institutional study were to describe anatomical variations in the TMJ detected using computed tomography (CT) in an equid population asymptomatic for TMJ disease and determine whether these variations were associated with patient signalment, reason for CT examination, or CT slice width. Medical records at eight hospitals were searched for horses that had head/neck CT scans and no clinical signs of TMJ disease. Age, breed, sex, clinical presentation, and CT slice width data were recorded. Alterations in CT contour and density of the mandibular condyles, mandibular fossae, and TMJ intra-articular discs were described for each horse. Generalized logistic regression was used to test associations between anatomical variations and horse age. A total of 1018 horses were sampled. Anatomical variations were found in TMJ CT images for 40% of horses and 29% of joints. These were dichotomous with regard to age. Horses <1 year old commonly had alterations in the shape and density of the mandibular condyle. Older horses commonly had spherical hypodensities within the mandibular condyles consistent with bone cysts; and hyperdense regions of the intra-articular disc consistent with dystrophic mineralization. Findings indicated that TMJ anatomic variations were common in CT images of younger and older horses asymptomatic for TMJ disease. Future studies are needed to more definitively characterize these CT variations using gross pathology and histopathology. PMID:26773281

  17. Evaluation of condylar positions in patients with temporomandibular disorders: A cone-beam computed tomographic study

    PubMed Central

    Imanimoghaddam, Mahrokh; Madani, Azam Sadat; Mahdavi, Pirooze; Bagherpour, Ali; Darijani, Mansoreh

    2016-01-01

    Purpose This study was performed to compare the condylar position in patients with temporomandibular joint disorders (TMDs) and a normal group by using cone-beam computed tomography (CBCT). Materials and Methods In the TMD group, 25 patients (5 men and 20 women) were randomly selected among the ones suffering from TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The control group consisted of 25 patients (8 men and 17 women) with normal temporomandibular joints (TMJs) who were referred to the radiology department in order to undergo CBCT scanning for implant treatment in the posterior maxilla. Linear measurements from the superior, anterior, and posterior joint spaces between the condyle and glenoid fossa were made through defined landmarks in the sagittal view. The inclination of articular eminence was also determined. Results The mean anterior joint space was 2.3 mm in the normal group and 2.8 mm in the TMD group, respectively. The results showed that there was a significant correlation between the superior and posterior joint spaces in both the normal and TMD groups, but it was only in the TMD group that the correlation coefficient among the dimensions of anterior and superior spaces was significant. There was a significant correlation between the inclination of articular eminence and the size of the superior and posterior spaces in the normal group. Conclusion The average dimension of the anterior joint space was different between the two groups. CBCT could be considered a useful diagnostic imaging modality for TMD patients. PMID:27358820

  18. The Diminishing Role of Pelvic Stability Evaluation in the Era of Computed Tomographic Scanning

    PubMed Central

    Fu, Chih-Yuan; Teng, Lan-Hsuan; Liao, Chien-Hung; Hsu, Yu-Pao; Wang, Shang-Yu; Kuo, Ling-Wei; Yuan, Kuo-Ching

    2016-01-01

    Abstract Pelvic fractures can result in life-threatening hemorrhages or other associated injuries. Therefore, computed tomography (CT) scanning plays a key role in the management of pelvic fracture patients. However, CT scanning is utilized as an adjunct in secondary survey according to traditional Advanced Trauma Life Support (ATLS) guidelines, whereas pelvic x-ray is used as a primary tool to evaluate pelvic stability and the necessity of further CT scanning. In the current study, we attempted to evaluate the role of CT scanning in the era of advanced technology. The significance of pelvic stability was also analyzed. From January 2012 to December 2014, the trauma registry and medical records of pelvic fracture patients were retrospectively reviewed. A 64-slice multidetector CT scanner was used in our emergency department as a standard diagnostic tool for evaluating trauma patients. Pelvic x-ray was used as a primary tool for screening pelvic fractures, and pelvic stability was evaluated accordingly. CT scans were performed in patients with unstable pelvic fractures, suspected associated intra-abdominal injuries (IAIs), or other conditions based on the physicians’ clinical judgment. The clinical features of patients with stable and unstable pelvic fractures were compared. The patients with stable pelvic fractures were analyzed to determine the characteristics associated with retroperitoneal hemorrhage (RH) or IAIs. Patients with stable pelvic fractures were also compared based on whether they underwent a CT scan. A total of 716 patients were enrolled in this study. There were 533 (74.4%) patients with stable pelvic fractures. Of these patients, there were 66 (12.4%) and 50 (9.4%) patients with associated RH and IAI, respectively. There were no significant differences between the patients with associated RH based on their primary evaluation (vital signs, volume of blood transfusion, and hemoglobin level). Similarly, the demographics and the primary evaluation

  19. Computational engine structural analysis

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Johns, R. H.

    1986-01-01

    A significant research activity at the NASA Lewis Research Center is the computational simulation of complex multidisciplinary engine structural problems. This simulation is performed using computational engine structural analysis (CESA) which consists of integrated multidisciplinary computer codes in conjunction with computer post-processing for problem-specific application. A variety of the computational simulations of specific cases are described in some detail in this paper. These case studies include: (1) aeroelastic behavior of bladed rotors, (2) high velocity impact of fan blades, (3) blade-loss transient response, (4) rotor/stator/squeeze-film/bearing interaction, (5) blade-fragment/rotor-burst containment, and (6) structural behavior of advanced swept turboprops. These representative case studies are selected to demonstrate the breath of the problems analyzed and the role of the computer including post-processing and graphical display of voluminous output data.

  20. Clamshell tomograph

    DOEpatents

    Derenzo, Stephen E.; Budinger, Thomas F.

    1984-01-01

    In brief, the invention is a tomograph modified to be in a clamshell configuration so that the ring or rings may be moved to multiple sampling positions. The tomograph includes an array of detectors arranged in successive adjacent relative locations along a closed curve in a first position in a selected plane, and means for securing the detectors in the relative locations in a first sampling position. The securing means is movable in the plane in two sections and pivotable at one p The U.S. Government has rights in this invention pursuant to Contract No. W-7405-ENG-48 between the U.S. Department of Energy and the University of California.

  1. X-ray tomographic microscopy analysis of the dendrite orientation transition in Al-Zn

    NASA Astrophysics Data System (ADS)

    Friedli, Jonathan; Fife, Julie L.; Di Napoli, Paolo; Rappaz, Michel

    2012-07-01

    Recently, Gonzales and Rappaz [Met. Mat. Trans. A37:2797, 2006] showed the influence of an increasing zinc content on the growth directions of aluminum dendrites. langle100rangle and langle110rangle dendrites were observed below 25wt.% and above 55wt.% zinc, respectively, whereas textured seaweeds and langle320rangle dendrites were observed at intermediate compositions. Considering the complexity of these structures, it is necessary to first characterize them in further details and second, to model them using the phase field method. The so-called Dendrite Orientation Transition (DOT) was thus reinvestigated in quenched Bridgman solidification samples. The combination of X-ray tomographic microscopy and electron backscattered diffraction (EBSD) analysis on a whole range of compositions, from 5 to 90wt.% Zn, allowed insights with unprecedented details about texture, growth directions and mechanisms of the aforementioned structures. We show that seaweeds rather than dendrites are found at all intermediate compositions. Their growth was confirmed to be constrained within a (100) symmetry plane. However, new findings indicate that the observed macroscopic texture does not necessarily correspond to the actual growth directions of the microstructure. Further, it seems to operate by an alternating growth direction mechanism and could be linked to the competition between the langle100rangle and langle110rangle characters of regular dendrites observed at the limits of the DOT. These characters, as well as 3D seaweeds, are observed in phase-field simulations of equiaxed growth and directional solidification, respectively. This study emphasizes the importance of accurate experimental data to validate numerical models and details the progress that such combinations provide for the understanding of growth mechanisms.

  2. Voronoï analysis of bubbly flows via ultrafast X-ray tomographic imaging

    NASA Astrophysics Data System (ADS)

    Lau, Yuk Man; Müller, Karolin; Azizi, Salar; Schubert, Markus

    2016-03-01

    Although clustering of bubbles plays a significant role in bubble column reactors regarding the heat and mass transfer due to bubble-bubble and flow field interactions, it has yet to be fully understood. Contrary to flows in bubble columns, most literature studies on clustering report numerical and experimental results on dilute or micro-bubbly flows. In this paper, clustering of bubbles in a cylindrical bubble column of 100 mm diameter is experimentally investigated. Ultrafast X-ray tomographic imaging is used to obtain the bubble positions within a hybrid Eulerian framework. By means of Voronoï analysis, the clustering behavior of bubbles is investigated. Experiments are performed with different superficial gas velocities, where Voronoï diagrams are constructed at several column heights. From the PDFs of the Voronoï diagrams, it is shown that the bubble structuring in terms of Voronoï cell volumes develops slower than the bubble size distribution. The latter reaches a steady state earlier with increasing column height. The measured PDFs are compared with the PDF of randomly distributed points, which showed that the amount of bubbles as part of clusters (Voronoï cells < V/overline{V}_{cluster}) as well as bubbles as part of voids (Voronoï cells > V/overline{V}_{void}) increases with the superficial gas velocity. It is found that all experiments have an approximate cluster limit V/overline{V}_{cluster} of 0.63, while the void limit V/overline{V}_{void} varies between 1.5 and 3.0.

  3. A Neural Network Model for the Tomographic Analysis of Irradiated Nuclear Fuel Rods

    SciTech Connect

    Craciunescu, Teddy

    2004-04-15

    A tomographic method based on a multilayer feed-forward artificial neural network is proposed for the reconstruction of gamma-radioactive fission product distribution in irradiated nuclear fuel rods. The quality of the method is investigated as compared to a conventional technique on experimental results concerning a Canada deuterium uranium reactor (CANDU)-type fuel rod irradiated in a TRIGA reactor.

  4. Comparative evaluation of the cadaveric, radiographic and computed tomographic anatomy of the heads of green iguana (Iguana iguana) , common tegu ( Tupinambis merianae) and bearded dragon ( Pogona vitticeps)

    PubMed Central

    2012-01-01

    Background Radiology and computed tomography are the most commonly available diagnostic tools for the diagnosis of pathologies affecting the head and skull in veterinary practice. Nevertheless, accurate interpretation of radiographic and CT studies requires a thorough knowledge of the gross and the cross-sectional anatomy. Despite the increasing success of reptiles as pets, only a few reports over their normal imaging features are currently available. The aim of this study is to describe the normal cadaveric, radiographic and computed tomographic features of the heads of the green iguana, tegu and bearded dragon. Results 6 adult green iguanas, 4 tegus, 3 bearded dragons, and, the adult cadavers of : 4 green iguana, 4 tegu, 4 bearded dragon were included in the study. 2 cadavers were dissected following a stratigraphic approach and 2 cadavers were cross-sectioned for each species. These latter specimens were stored in a freezer (−20°C) until completely frozen. Transversal sections at 5 mm intervals were obtained by means of an electric band-saw. Each section was cleaned and photographed on both sides. Radiographs of the head of each subject were obtained. Pre- and post- contrast computed tomographic studies of the head were performed on all the live animals. CT images were displayed in both bone and soft tissue windows. Individual anatomic structures were first recognised and labelled on the anatomic images and then matched on radiographs and CT images. Radiographic and CT images of the skull provided good detail of the bony structures in all species. In CT contrast medium injection enabled good detail of the soft tissues to be obtained in the iguana whereas only the eye was clearly distinguishable from the remaining soft tissues in both the tegu and the bearded dragon. Conclusions The results provide an atlas of the normal anatomical and in vivo radiographic and computed tomographic features of the heads of lizards, and this may be useful in interpreting any

  5. Spinopelvic dissociation: multidetector computed tomographic evaluation of fracture patterns and associated injuries at a single level 1 trauma center.

    PubMed

    Gupta, Pushpender; Barnwell, Jonathan C; Lenchik, Leon; Wuertzer, Scott D; Miller, Anna N

    2016-06-01

    The objective of the present study is to evaluate multidetector computed tomographic (MDCT) fracture patterns and associated injuries in patients with spinopelvic dissociation (SPD). Our institutional trauma registry database was reviewed from Jan. 1, 2006, to Sept. 30, 2012, specifically evaluating patients with sacral fractures. MDCT scans of patients with sacral fractures were reviewed to determine the presence of SPD. SPD cases were characterized into the following fracture patterns: U-shaped, Y-shaped, T-shaped, H-shaped, and burst. The following MDCT features were recorded: level of the horizontal fracture, location of vertical fracture, kyphosis between major fracture fragments, displacement of fracture fragment, narrowing of central spinal canal, narrowing of neural foramina, and extension into sacroiliac joints. Quantitative evaluation of the sacral fractures was performed in accordance with the consensus statement by the Spine Trauma Study Group. Medical records were reviewed to determine associated pelvic and non-pelvic fractures, bladder and bowel injuries, nerve injuries, and type of surgical intervention. Twenty-one patients had SPD, of whom 13 were men and eight were women. Mean age was 41.8 years (range 18.8 to 87.7). Five fractures (24 %) were U-shaped, six (29 %) H-shaped, four (19 %) Y-shaped, and six (29 %) burst. Nine patients (43 %) had central canal narrowing, and 19 (90 %) had neural foramina narrowing. Eleven patients (52 %) had kyphotic angulation between major fracture fragments, and seven patients (33 %) had either anterior (24 %) or posterior (10 %) displacement of the proximal fracture fragment. Fourteen patients (67 %) had associated pelvic fractures, and 20 (95 %) had associated non-pelvic fractures. Two patients (10 %) had associated urethral injuries, and one (5 %) had an associated colon injury. Seven patients (33 %) had associated nerve injuries. Six patients (29 %) had surgical fixation while 15 (71 %) were

  6. Coronary Atherosclerotic Plaque Detected by Computed Tomographic Angiography in Subjects with Diabetes Compared to Those without Diabetes

    PubMed Central

    Khazai, Bahram; Luo, Yanting; Rosenberg, Steven; Wingrove, James; Budoff, Matthew J

    2015-01-01

    Objectives Little data are available regarding coronary plaque composition and semi-quantitative scores in individuals with diabetes; the extent to which diabetes may affect the presence and extent of Coronary Artery Calcium (CAC) needs more evaluation. Considering that this information may be of great value in formulating preventive interventions in this population, we compared these findings in individuals with diabetes to those without. Methods Multi-Detector Computed Tomographic (MDCT) images of 861 consecutive patients with diabetes who were referred to Los Angeles Biomedical Research Institute from January 2000 to September 2012, were evaluated using a 15–coronary segment model. All 861 patients underwent calcium scoring and from these; 389 had coronary CT angiography (CTA). CAC score was compared to 861 age, sex and ethnicity matched controls without diabetes after adjustment for Body Mass Index (BMI), family history of coronary artery disease, hyperlipidemia, hypertension and smoking. Segment Involvement Score (SIS; the total number of segments with any plaque), Segment Stenosis Score (SSS; the sum of maximal stenosis score per segment), Total Plaque Score (TPS; the sum of the plaque amount per segment) and plaque compositionwere compared to 389 age, sex and ethnicity matched controls without diabetes after adjustment for BMI, family history of coronary artery disease, hyperlipidemia, hypertension and smoking. Results Diabetes was positively correlated to the presence and extent of CAC (P<0.0001 for both). SIS, SSS and TPS were significantly higher in those with diabetes (P<0.0001). Number of mixed and calcified plaques were significantly higher in those with diabetes (P = 0.018 and P<0.001 respectively) but there was no significant difference in the number of non-calcified plaques between the two groups (P = 0.398). Conclusions Patients with diabetes have higher CAC and semi-quantitative coronary plaque scores compared to the age, gender and ethnicity

  7. Analysis of an Optimized MLOS Tomographic Reconstruction Algorithm and Comparison to the MART Reconstruction Algorithm

    NASA Astrophysics Data System (ADS)

    La Foy, Roderick; Vlachos, Pavlos

    2011-11-01

    An optimally designed MLOS tomographic reconstruction algorithm for use in 3D PIV and PTV applications is analyzed. Using a set of optimized reconstruction parameters, the reconstructions produced by the MLOS algorithm are shown to be comparable to reconstructions produced by the MART algorithm for a range of camera geometries, camera numbers, and particle seeding densities. The resultant velocity field error calculated using PIV and PTV algorithms is further minimized by applying both pre and post processing to the reconstructed data sets.

  8. Impaired fasting glucose is associated with increased severity of subclinical coronary artery disease compared to patients with diabetes and normal fasting glucose: evaluation by coronary computed tomographic angiography

    PubMed Central

    Gurudevan, Swaminatha; Garg, Pankaj; Malik, Shaista; Khattar, Ramni; Saremi, Farhood; Hecht, Harvey; DeMaria, Anthony; Narula, Jagat

    2016-01-01

    Objective This study was designed to evaluate the severity of subclinical atherosclerosis in patients with asymptomatic impaired fasting glucose (IFG) compared to those with diabetes mellitus (DM) and normal fasting glucose (NFG), as measured by coronary computed tomographic angiography (CCTA). Design Subjects were divided into three groups: NFG (<100 mg/dL), IFG (100–125 mg/dL) and DM. Coronary artery calcium on non-contrast CT and plaque analysis on CCTA were performed. Setting University hospital, single centre. Participants 216 asymptomatic participants prospectively underwent CCTA for the evaluation of coronary artery disease (CAD). Primary and secondary outcome measures Atherosclerotic plaque burden in IFG compared to NFG patients. Results 2664 segments were analysed in 120 NFG, 44 IFG and 52 DM participants. The mean calcium scores were 178±395, 259±510 and 414±836 for NFG, IFG and DM, respectively (p=0·037). The mean plaque burdens in the NFG, IFG and DM groups were 0.31±0.45, 0.50±0.69 and 0.68±0.69, respectively (p=0·0007). A greater proportion of patients with DM (19/52, 36.5%) and IFG (13/44, 29.5%) had obstructive CAD compared to those with NFG (16/120, 13.3%) (p=0.0015). The number of segments with severe disease was significantly higher in the DM (60/637, 9.4%) and IFG (42/539, 7.8%) groups compared to that in the NFG group (34/1488, 2.3%) (p=0.0001). Conclusions (1) IFG and DM have significantly higher, but comparable, calcium scores, plaque burden and obstructive CAD compared to NFG in asymptomatic individuals. (2) Pending corroboration by other reports, more intensive efforts may be devoted to the evaluation and treatment of patients with IFG. PMID:27531720

  9. Computational Analysis of Behavior.

    PubMed

    Egnor, S E Roian; Branson, Kristin

    2016-07-01

    In this review, we discuss the emerging field of computational behavioral analysis-the use of modern methods from computer science and engineering to quantitatively measure animal behavior. We discuss aspects of experiment design important to both obtaining biologically relevant behavioral data and enabling the use of machine vision and learning techniques for automation. These two goals are often in conflict. Restraining or restricting the environment of the animal can simplify automatic behavior quantification, but it can also degrade the quality or alter important aspects of behavior. To enable biologists to design experiments to obtain better behavioral measurements, and computer scientists to pinpoint fruitful directions for algorithm improvement, we review known effects of artificial manipulation of the animal on behavior. We also review machine vision and learning techniques for tracking, feature extraction, automated behavior classification, and automated behavior discovery, the assumptions they make, and the types of data they work best with. PMID:27090952

  10. Medical ultrasonic tomographic system

    NASA Technical Reports Server (NTRS)

    Heyser, R. C.; Lecroissette, D. H.; Nathan, R.; Wilson, R. L.

    1977-01-01

    An electro-mechanical scanning assembly was designed and fabricated for the purpose of generating an ultrasound tomogram. A low cost modality was demonstrated in which analog instrumentation methods formed a tomogram on photographic film. Successful tomogram reconstructions were obtained on in vitro test objects by using the attenuation of the fist path ultrasound signal as it passed through the test object. The nearly half century tomographic methods of X-ray analysis were verified as being useful for ultrasound imaging.

  11. Evidence for entanglement and full tomographic analysis of Bell states in a single-neutron system

    SciTech Connect

    Hasegawa, Yuji; Loidl, Rudolf; Filipp, Stefan; Badurek, Gerald; Klepp, Juergen; Rauch, Helmut

    2007-11-15

    Tomographic measurements of Bell states of a single-neutron system in an interferometer were carried out. The spin-path joint measurements exhibit clear evidence of entanglement. Reconstructions of the density matrices of, practically complete, Bell states were accomplished. The fidelities as well as the concurrences of the generated states are determined by 0.79 and 0.75 as well as 0.59 and 0.52, respectively, which are again clear evidence of the spin-path entanglement in a single-neutron system.

  12. Tomographic bioluminescence imaging by use of a combined optical-PET (OPET) system: a computer simulation feasibility study

    NASA Astrophysics Data System (ADS)

    Alexandrakis, George; Rannou, Fernando R.; Chatziioannou, Arion F.

    2005-09-01

    The feasibility and limits in performing tomographic bioluminescence imaging with a combined optical-PET (OPET) system were explored by simulating its image formation process. A micro-MRI based virtual mouse phantom was assigned appropriate tissue optical properties to each of its segmented internal organs at wavelengths spanning the emission spectrum of the firefly luciferase at 37 °C. The TOAST finite-element code was employed to simulate the diffuse transport of photons emitted from bioluminescence sources in the mouse. OPET measurements were simulated for single-point, two-point and distributed bioluminescence sources located in different organs such as the liver, the kidneys and the gut. An expectation maximization code was employed to recover the intensity and location of these simulated sources. It was found that spectrally resolved measurements were necessary in order to perform tomographic bioluminescence imaging. The true location of emission sources could be recovered if the mouse background optical properties were known a priori. The assumption of a homogeneous optical property background proved inadequate for describing photon transport in optically heterogeneous tissues and led to inaccurate source localization in the reconstructed images. The simulation results pointed out specific methodological challenges that need to be addressed before a practical implementation of OPET-based bioluminescence tomography is achieved.

  13. Optimization of tomographic reconstruction workflows on geographically distributed resources.

    PubMed

    Bicer, Tekin; Gürsoy, Dogˇa; Kettimuthu, Rajkumar; De Carlo, Francesco; Foster, Ian T

    2016-07-01

    New technological advancements in synchrotron light sources enable data acquisitions at unprecedented levels. This emergent trend affects not only the size of the generated data but also the need for larger computational resources. Although beamline scientists and users have access to local computational resources, these are typically limited and can result in extended execution times. Applications that are based on iterative processing as in tomographic reconstruction methods require high-performance compute clusters for timely analysis of data. Here, time-sensitive analysis and processing of Advanced Photon Source data on geographically distributed resources are focused on. Two main challenges are considered: (i) modeling of the performance of tomographic reconstruction workflows and (ii) transparent execution of these workflows on distributed resources. For the former, three main stages are considered: (i) data transfer between storage and computational resources, (i) wait/queue time of reconstruction jobs at compute resources, and (iii) computation of reconstruction tasks. These performance models allow evaluation and estimation of the execution time of any given iterative tomographic reconstruction workflow that runs on geographically distributed resources. For the latter challenge, a workflow management system is built, which can automate the execution of workflows and minimize the user interaction with the underlying infrastructure. The system utilizes Globus to perform secure and efficient data transfer operations. The proposed models and the workflow management system are evaluated by using three high-performance computing and two storage resources, all of which are geographically distributed. Workflows were created with different computational requirements using two compute-intensive tomographic reconstruction algorithms. Experimental evaluation shows that the proposed models and system can be used for selecting the optimum resources, which in turn can

  14. Correlative multiple porosimetries for reservoir sandstones with adoption of a new reference-sample-guided computed-tomographic method

    PubMed Central

    Jin, Jae Hwa; Kim, Junho; Lee, Jeong-Yil; Oh, Young Min

    2016-01-01

    One of the main interests in petroleum geology and reservoir engineering is to quantify the porosity of reservoir beds as accurately as possible. A variety of direct measurements, including methods of mercury intrusion, helium injection and petrographic image analysis, have been developed; however, their application frequently yields equivocal results because these methods are different in theoretical bases, means of measurement, and causes of measurement errors. Here, we present a set of porosities measured in Berea Sandstone samples by the multiple methods, in particular with adoption of a new method using computed tomography and reference samples. The multiple porosimetric data show a marked correlativeness among different methods, suggesting that these methods are compatible with each other. The new method of reference-sample-guided computed tomography is more effective than the previous methods when the accompanied merits such as experimental conveniences are taken into account. PMID:27445105

  15. Correlative multiple porosimetries for reservoir sandstones with adoption of a new reference-sample-guided computed-tomographic method

    NASA Astrophysics Data System (ADS)

    Jin, Jae Hwa; Kim, Junho; Lee, Jeong-Yil; Oh, Young Min

    2016-07-01

    One of the main interests in petroleum geology and reservoir engineering is to quantify the porosity of reservoir beds as accurately as possible. A variety of direct measurements, including methods of mercury intrusion, helium injection and petrographic image analysis, have been developed; however, their application frequently yields equivocal results because these methods are different in theoretical bases, means of measurement, and causes of measurement errors. Here, we present a set of porosities measured in Berea Sandstone samples by the multiple methods, in particular with adoption of a new method using computed tomography and reference samples. The multiple porosimetric data show a marked correlativeness among different methods, suggesting that these methods are compatible with each other. The new method of reference-sample-guided computed tomography is more effective than the previous methods when the accompanied merits such as experimental conveniences are taken into account.

  16. Histological and computed tomographic evaluation of a parasitic conjoined twin in hybrid catfish (Ictalurus punctatus [Rafinesque] X Ictalurus furcatus [Lesueur]).

    PubMed

    Leach, C A; Thomas, M W; Cooley, A J; Waldbieser, G C; Bosworth, B G; Torrans, E L; Khoo, L H

    2014-06-01

    There is growing use of hybrid catfish (Ictalurus punctatus ♀ X Ictalurus furcatus ♂) in commercial aquaculture to utilize hybrid vigour to improve production A conjoined twin specimen found during the course of production studies by the United States Department of Agriculture Catfish Genetic Research Unit (USDA-CGRU) was submitted to the Aquatic Research and Diagnostic Laboratory (ARDL). After preliminary inspection, it was transported to Mississippi State University, College of Veterinary Medicine for further evaluation. The specimen was examined using both computed radiography and computed tomography antemortem. Following humane euthanasia, the specimen was examined both grossly and histologically. Tissues from both fish were also submitted for genetic analysis to determine whether twins were derived from the same egg. This report records the presentation and examination of a pair of conjoined hybrid catfish (I. punctatus X Ictalurus furcatus). PMID:23991936

  17. Correlative multiple porosimetries for reservoir sandstones with adoption of a new reference-sample-guided computed-tomographic method.

    PubMed

    Jin, Jae Hwa; Kim, Junho; Lee, Jeong-Yil; Oh, Young Min

    2016-01-01

    One of the main interests in petroleum geology and reservoir engineering is to quantify the porosity of reservoir beds as accurately as possible. A variety of direct measurements, including methods of mercury intrusion, helium injection and petrographic image analysis, have been developed; however, their application frequently yields equivocal results because these methods are different in theoretical bases, means of measurement, and causes of measurement errors. Here, we present a set of porosities measured in Berea Sandstone samples by the multiple methods, in particular with adoption of a new method using computed tomography and reference samples. The multiple porosimetric data show a marked correlativeness among different methods, suggesting that these methods are compatible with each other. The new method of reference-sample-guided computed tomography is more effective than the previous methods when the accompanied merits such as experimental conveniences are taken into account. PMID:27445105

  18. Identification and analysis of boundary layer structures in Tomographic PIV data

    NASA Astrophysics Data System (ADS)

    Ortiz-Duenas, Cecilia; Saikrishnan, Neelakantan; Longmire, Ellen

    2009-11-01

    Tomographic particle image velocimetry data were acquired in a turbulent boundary layer flow generated in a wind tunnel facility. The friction Reynolds number Reτ was 1160. Measurement volumes of streamwise and spanwise dimension 0.7δ and wall normal thickness 0.07δ, which resolved the range z^+ = 70-150, were analyzed using custom software. Various criteria, including streamwise velocity, two- and three-dimensional swirl, individual vorticity components, and Reynolds shear stress, in combination with region growing and coincidence algorithms, were employed to identify and characterize coherent structures present in instantaneous fields. The results of the present study will be described and also compared with results from earlier experiments by Ganapathisubramani et al., 2003, 2006, that relied on planar PIV data only.

  19. Moving image analysis to the cloud: A case study with a genome-scale tomographic study

    NASA Astrophysics Data System (ADS)

    Mader, Kevin; Stampanoni, Marco

    2016-01-01

    Over the last decade, the time required to measure a terabyte of microscopic imaging data has gone from years to minutes. This shift has moved many of the challenges away from experimental design and measurement to scalable storage, organization, and analysis. As many scientists and scientific institutions lack training and competencies in these areas, major bottlenecks have arisen and led to substantial delays and gaps between measurement, understanding, and dissemination. We present in this paper a framework for analyzing large 3D datasets using cloud-based computational and storage resources. We demonstrate its applicability by showing the setup and costs associated with the analysis of a genome-scale study of bone microstructure. We then evaluate the relative advantages and disadvantages associated with local versus cloud infrastructures.

  20. Advances in the use of tomographic inspection techniques for non-destructive analysis of geometric conductor position and correlation with magnetic cross-section modeling

    SciTech Connect

    Bein, D.; Snitchler, G.; Rabaey, G.F.; Bolger, J.; Crane, R. Morgan, I.L.; Vinson, M.

    1993-05-01

    Industrial Computerized Tomography has been applied to magnet components in various stages of the manufacturing process. These Computerized Tomographic images can be analyzed to infer detailed dimensional information about magnet component positions (conductor, wedges, collars, etc.) throughout the magnet manufacturing process (cable winding, collaring, yoked/skinned). An analysis technique will be presented and measurement accuracies will be discussed.

  1. Computed tomographic observations pertinent to intracranial venous thrombotic and occulsive disease in childhood: state of the art, some new data, and hypotheses

    SciTech Connect

    Segall, H.D.; Ahmadi, J.; McComb, J.G.; Zee, C.S.; Becker, T.S.; Han, J.S.

    1982-05-01

    Selected topics are discussed and new observations recorded regarding computed tomographic (CT) evaluation of intracranial venous thrombotic and occlusive disease in childhood. High density of the vein of Galen and adjacent venous sinuses (relative to brain) can be seen normally in children. A number of potential pitfalls in the diagnosis of superior sagittal sinus thrombosis are also disclosed. A case of cavernous sinus thrombosis with abnormal CT changes is included. In addition, the normal CT appearance of the cavernous sinus is described. In some cases, filling defects occur which appear to correlate with normal cranial nerves. An unusual case of venous sinus occlusion by neoplasm (sarcoma) is presented. Finally, new findings in the Sturge-Weber syndrome are analyzed. Enhancement of the brain in this condition may have its basis in altered circulation resulting from fundamental venous abnormalities.

  2. Validation of a technique for integration of a digital dental model into stereophotogrammetric images of the face using cone-beam computed tomographic data.

    PubMed

    Codari, Marina; Pucciarelli, Valentina; Tommasi, Davide G; Sforza, Chiarella

    2016-06-01

    We wanted to find and validate a new way to visualise patients' faces and their dental arches non-invasively. The stereophotogrammetric images of the faces and the digitised dental casts of seven healthy subjects were analysed. Point-based and surface-based recording techniques matched the facial image with those of the mandibular and maxillary dental arches in their relative positions. The cone-beam computed tomographic (CT) images of the same subjects were analysed retrospectively. Twenty-eight dentofacial distances were obtained on cone-beam CT images and on the recorded facial and dental surfaces. The median (IQR) distances of more than 96% of the measurements did not differ significantly. PMID:26852270

  3. Computed tomographic, magnetic resonance imaging, and cross-sectional anatomic features of the manus in a normal American black bear (Ursus americanus).

    PubMed

    Ober, C P; Freeman, L E

    2010-06-01

    The purpose of this study was to provide a detailed description of cross-sectional anatomic structures of the manus of a black bear cadaver and correlate anatomic findings with corresponding features in computed tomographic (CT) and magnetic resonance (MR) images. CT, MR imaging, and transverse sectioning were performed on the thoracic limb of a cadaver female black bear which had no evidence of lameness or thoracic limb abnormality prior to death. Features in CT and MR images corresponding to clinically important anatomic structures in anatomic sections were identified. Most of the structures identified in transverse anatomic sections were also identified using CT and MR imaging. Bones, muscles and tendons were generally easily identified with both imaging modalities, although divisions between adjacent muscles were rarely visible with CT and only visible sometimes with MR imaging. Vascular structures could not be identified with either imaging modality. PMID:20500743

  4. Clinical outcomes of fractional flow reserve by computed tomographic angiography-guided diagnostic strategies vs. usual care in patients with suspected coronary artery disease: the prospective longitudinal trial of FFRCT: outcome and resource impacts study

    PubMed Central

    Douglas, Pamela S.; Pontone, Gianluca; Hlatky, Mark A.; Patel, Manesh R.; Norgaard, Bjarne L.; Byrne, Robert A.; Curzen, Nick; Purcell, Ian; Gutberlet, Matthias; Rioufol, Gilles; Hink, Ulrich; Schuchlenz, Herwig Walter; Feuchtner, Gudrun; Gilard, Martine; Andreini, Daniele; Jensen, Jesper M.; Hadamitzky, Martin; Chiswell, Karen; Cyr, Derek; Wilk, Alan; Wang, Furong; Rogers, Campbell; De Bruyne, Bernard

    2015-01-01

    Aims In symptomatic patients with suspected coronary artery disease (CAD), computed tomographic angiography (CTA) improves patient selection for invasive coronary angiography (ICA) compared with functional testing. The impact of measuring fractional flow reserve by CTA (FFRCT) is unknown. Methods and results At 11 sites, 584 patients with new onset chest pain were prospectively assigned to receive either usual testing (n = 287) or CTA/FFRCT (n = 297). Test interpretation and care decisions were made by the clinical care team. The primary endpoint was the percentage of those with planned ICA in whom no significant obstructive CAD (no stenosis ≥50% by core laboratory quantitative analysis or invasive FFR < 0.80) was found at ICA within 90 days. Secondary endpoints including death, myocardial infarction, and unplanned revascularization were independently and blindly adjudicated. Subjects averaged 61 ± 11 years of age, 40% were female, and the mean pre-test probability of obstructive CAD was 49 ± 17%. Among those with intended ICA (FFRCT-guided = 193; usual care = 187), no obstructive CAD was found at ICA in 24 (12%) in the CTA/FFRCT arm and 137 (73%) in the usual care arm (risk difference 61%, 95% confidence interval 53–69, P< 0.0001), with similar mean cumulative radiation exposure (9.9 vs. 9.4 mSv, P = 0.20). Invasive coronary angiography was cancelled in 61% after receiving CTA/FFRCT results. Among those with intended non-invasive testing, the rates of finding no obstructive CAD at ICA were 13% (CTA/FFRCT) and 6% (usual care; P = 0.95). Clinical event rates within 90 days were low in usual care and CTA/FFRCT arms. Conclusions Computed tomographic angiography/fractional flow reserve by CTA was a feasible and safe alternative to ICA and was associated with a significantly lower rate of invasive angiography showing no obstructive CAD. PMID:26330417

  5. X-Ray Tomographic Reconstruction

    SciTech Connect

    Bonnie Schmittberger

    2010-08-25

    Tomographic scans have revolutionized imaging techniques used in medical and biological research by resolving individual sample slices instead of several superimposed images that are obtained from regular x-ray scans. X-Ray fluorescence computed tomography, a more specific tomography technique, bombards the sample with synchrotron x-rays and detects the fluorescent photons emitted from the sample. However, since x-rays are attenuated as they pass through the sample, tomographic scans often produce images with erroneous low densities in areas where the x-rays have already passed through most of the sample. To correct for this and correctly reconstruct the data in order to obtain the most accurate images, a program employing iterative methods based on the inverse Radon transform was written. Applying this reconstruction method to a tomographic image recovered some of the lost densities, providing a more accurate image from which element concentrations and internal structure can be determined.

  6. Association of achondroplasia with Down syndrome: difficulty in prenatal diagnosis by sonographic and 3-D helical computed tomographic analyses.

    PubMed

    Kaga, Akimune; Murotsuki, Jun; Kamimura, Miki; Kimura, Masato; Saito-Hakoda, Akiko; Kanno, Junko; Hoshi, Kazuhiko; Kure, Shigeo; Fujiwara, Ikuma

    2015-05-01

    Achondroplasia and Down syndrome are relatively common conditions individually. But co-occurrence of both conditions in the same patient is rare and there have been no reports of fetal analysis of this condition by prenatal sonographic and three-dimensional (3-D) helical computed tomography (CT). Prenatal sonographic findings seen in persons with Down syndrome, such as a thickened nuchal fold, cardiac defects, and echogenic bowel were not found in the patient. A prenatal 3-D helical CT revealed a large head with frontal bossing, metaphyseal flaring of the long bones, and small iliac wings, which suggested achondroplasia. In a case with combination of achondroplasia and Down syndrome, it may be difficult to diagnose the co-occurrence prenatally without typical markers of Down syndrome. PMID:25385298

  7. Tomographic image via background subtraction using an x-ray projection image and a priori computed tomography

    SciTech Connect

    Zhang Jin; Yi Byongyong; Lasio, Giovanni; Suntharalingam, Mohan; Yu, Cedric

    2009-10-15

    Kilovoltage x-ray projection images (kV images for brevity) are increasingly available in image guided radiotherapy (IGRT) for patient positioning. These images are two-dimensional (2D) projections of a three-dimensional (3D) object along the x-ray beam direction. Projecting a 3D object onto a plane may lead to ambiguities in the identification of anatomical structures and to poor contrast in kV images. Therefore, the use of kV images in IGRT is mainly limited to bony landmark alignments. This work proposes a novel subtraction technique that isolates a slice of interest (SOI) from a kV image with the assistance of a priori information from a previous CT scan. The method separates structural information within a preselected SOI by suppressing contributions to the unprocessed projection from out-of-SOI-plane structures. Up to a five-fold increase in the contrast-to-noise ratios (CNRs) was observed in selected regions of the isolated SOI, when compared to the original unprocessed kV image. The tomographic image via background subtraction (TIBS) technique aims to provide a quick snapshot of the slice of interest with greatly enhanced image contrast over conventional kV x-ray projections for fast and accurate image guidance of radiation therapy. With further refinements, TIBS could, in principle, provide real-time tumor localization using gantry-mounted x-ray imaging systems without the need for implanted markers.

  8. Electron tomographic analysis of cytokinesis in the brown alga Silvetia babingtonii (Fucales, Phaeophyceae).

    PubMed

    Nagasato, Chikako; Kajimura, Naoko; Terauchi, Makoto; Mineyuki, Yoshinobu; Motomura, Taizo

    2014-11-01

    In brown algae, membrane resources for the new cell partition during cytokinesis are mainly flat cisternae (FCs) and Golgi-derived vesicles. We used electron tomography coupled with rapid freezing/freeze substitution of zygotes to clarify the structure of transient membrane compartments during cytokinesis in Silvetia zygotes. After mitosis, an amorphous membranous structure, considered to be an FC intermediate was observed near endoplasmic reticulum clusters, lying between two daughter nuclei. FCs were arrayed at the cytokinetic plane, and a tubular membranous network was formed around them. This network might be formed by the consecutive fusion of spherical vesicles that are linked to the edges of FCs to form a membranous network (MN). At the initial stage of the formation of a membranous sac (MS) from the MN, the MS had flat and swollen parts, with the latter showing membranous tunnels. Coated pits were detected with high frequency at the swollen parts of the MS. This observation indicated that membranous tunnels disappeared by recycling of excess membrane via endocytosis, and the swollen part became flat. The MN appeared at the edges of the growing MS. MN and the MN-MS complex were observed along the cytokinetic plane in several spaces. The MS expanded by the incorporation of MN or other MS in its neighborhood. With the maturation of the new cell partition membrane, the thickness of the MS became constant and the membrane cavity disappeared. The changes in the surface area and volume of the transient membrane compartment during cytokinesis were analyzed from the tomographic data. PMID:24671646

  9. Fluid-Dynamics of Underwater Flight in Sea Butterflies: Analysis using Tomographic PIV

    NASA Astrophysics Data System (ADS)

    Adhikari, D.; Murphy, D. W.; Webster, D. R.; Yen, J.

    2014-11-01

    Sea butterflies, Limacina helicina, swim in sea water with a pair of gelatinous ``wings'' (or parapodia). Their unique propulsion mechanism has been hypothesized to consist of a combination of drag-based propulsion (rowing) and lift-based propulsion (flapping). Drag-based propulsion utilizes maximum drag on the wings during power stroke, followed by minimum drag during recovery stroke. Lift-based propulsion, in contrast, utilizes a pressure difference between the top and bottom of the wings. We present the 3D kinematics of a free-swimming sea butterfly and its induced volumetric velocity field using tomographic PIV. Both upstroke and downstroke motions propel the animal (1 - 3 mm) upward in a sawtooth-like trajectory with average speed of 5 - 15 mm/s (Re = 5 - 45) and roll the calcareous shell forwards-and-backwards at 4 - 5 Hz. The rolling motion effectively positions the wings such that they stroke downward during both the power and recovery strokes, hence inducing upward motion during both phases. A clap-and-fling mechanism is observed at the beginning of the flapping cycle. As the wings come into contact, the velocity of the organism is 2 mm/s. During fling motion, high (unsteady) lift causes the organism velocity to reach 35 mm/s. Separation vortices are observed during the fling motion, and vortices with an opposite sense of rotation form closer to the base of the wing due to the upward translation of the organism. The separation vortices shed into the wake, as the organism translates upward, in the form of separate vortex pairs.

  10. Radiographic and Tomographic Analysis in Patients with Stickler Syndrome Type I

    PubMed Central

    Al Kaissi, Ali; Chehida, Farid Ben; Ganger, Rudolf; Kenis, Vladimir; Zandieh, Shahin; Hofstaetter, Jochen G; Klaushofer, Klaus; Grill, Franz

    2013-01-01

    Objective: To further investigate the underlying pathology of axial and appendicular skeletal abnormalities such as painful spine stiffness, gait abnormalities, early onset osteoarthritis and patellar instability in patients with Stickler syndrome type I. Radiographic and tomographic analyses were organized. Methods: From a series of Stickler syndrome patients followed from early life to late childhood. Ten patients (6 boys and four girls of different ethnic origins were consistent with the diagnosis of Stickler syndrome type I ). Phenotypic characterization was the baseline tool applied for all patients and genotypic correlation was performed on four families Results: A constellation of axial abnormalities namely; anterolateral ossification of the anterior longitudinal spinal ligament with subsequent fusion of two cervical vertebrae, early onset Forestier disease (progressive spinal hyperostosis with subsequent vertebral fusion on top of bridging osteophytes and “Bamboo-like spine” resembling ankylosing spondylitis) and severe premature spine degeneration were evident. Appendicular abnormalities in connection with generalized epiphyseal dysplasia were the underlying aetiology in patients with Intoeing gait and femoral anteversion, early onset severe osteoarthritis of the weight bearing joint. Remarkable trochleo-patellar dysplasia secondary to severe osteoarthritis causing effectively the development of patellar instability was additional pathology. Mutation of COL2A1 has been confirmed as the causative gene for Stickler syndrome type I Conclusion: We concluded that conventional radiographs and the molecular determination of a COL2A1 in patients with (Stickler syndrome type I) are insufficient tools to explain the reasons behind the tremendous magnitude of axial and appendicular skeletal abnormalities. We were able to modify the criteria of the clinical phenotype as designated by Rose et al in accordance with the novel axial and appendicular criteria as

  11. Development of a portable x-ray computed tomographic imaging system for drill-site investigation of recovered core

    SciTech Connect

    Freifeld, Barry M.; Kneafsey, Timothy J.; Tomutsa, Liviu; Pruess, Jacob

    2003-05-01

    A portable x-ray computed tomography (CT) system was constructed for imaging core at drill sites. Performing drill-site-based x-ray scanning and CT analysis permits rapid evaluation of core properties (such as density, lithologic structure, and macroporosity distribution) and allows for real-time decision making for additional core-handling procedures. Because of the speed with which scanning is performed, systematic imaging and electronic cataloging of all retrieved core is feasible. Innovations (such as a novel clamshell shielding arrangement integrated with system interlocks) permit safe operation of the x-ray system in a busy core handling area. The minimization of the volume encapsulated with shielding reduces the overall system weight and facilitates instrument portability. The x-ray system as originally fabricated had a 110 kV x-ray source with a fixed 300-micron focal spot size. A 15 cm image intensifier with a cesium iodide phosphor input screen was coupled to a CCD for image capture. The CT system has since been modified with a 130 kV micro-focal x-ray source. With the x-ray system's variable focal spot size, high-resolution studies (10-micron resolution) can be performed on core plugs and coarser (100-micron resolution) images can be acquired of whole drill cores. The development of an aluminum compensator has significantly improved the dynamic range and accuracy of the system. An x-ray filter has also been incorporated, permitting rapid acquisition of multi-energy scans for more quantitative analysis of sample mineralogy. The x-ray CT system has operated reliably under extreme field conditions, which have varied from shipboard to arctic.

  12. Quantitative Ex-Vivo Micro-Computed Tomographic Imaging of Blood Vessels and Necrotic Regions within Tumors

    PubMed Central

    Downey, Charlene M.; Singla, Arvind K.; Villemaire, Michelle L.; Buie, Helen R.; Boyd, Steven K.; Jirik, Frank R.

    2012-01-01

    Techniques for visualizing and quantifying the microvasculature of tumors are essential not only for studying angiogenic processes but also for monitoring the effects of anti-angiogenic treatments. Given the relatively limited information that can be gleaned from conventional 2-D histological analyses, there has been considerable interest in methods that enable the 3-D assessment of the vasculature. To this end, we employed a polymerizing intravascular contrast medium (Microfil) and micro-computed tomography (micro-CT) in combination with a maximal spheres direct 3-D analysis method to visualize and quantify ex-vivo vessel structural features, and to define regions of hypoperfusion within tumors that would be indicative of necrosis. Employing these techniques we quantified the effects of a vascular disrupting agent on the tumor vasculature. The methods described herein for quantifying whole tumor vascularity represent a significant advance in the 3-D study of tumor angiogenesis and evaluation of novel therapeutics, and will also find potential application in other fields where quantification of blood vessel structure and necrosis are important outcome parameters. PMID:22848565

  13. Neural network analysis for geological interpretation of tomographic images beneath the Japan Islands

    NASA Astrophysics Data System (ADS)

    Kuwatani, T.; Toriumi, M.

    2009-12-01

    prediction of lithology and its structure, we will use the additional input data sets, such as tomographic images of random velocity fluctuation (Takahashi et al. 2009) and b-value mapping data. Additionally, different kinds of data sets, including the experimental and petrological results (e.g. Christensen 1991; Hacker et al. 2003) can be applied to our analyses.

  14. Comparative evaluation of the cadaveric and computed tomographic features of the coelomic cavity in the green iguana (Iguana iguana), black and white tegu (Tupinambis merianae) and bearded dragon (Pogona vitticeps).

    PubMed

    Banzato, T; Selleri, P; Veladiano, I A; Zotti, A

    2013-12-01

    Contrast-enhanced computed tomographic studies of the coelomic cavity in four green iguanas, four black and white tegus and four bearded dragons were performed using a conventional CT scanner. Anatomical reference cross sections were obtained from four green iguana, four black and white tegu and six bearded dragon cadavers; the specimens were stored in a -20°C freezer for 24 h then sliced into 5-mm intervals. The frozen sections were cleaned with water and photographed on both sides. The individual anatomical structures were identified by means of the available literature; these were labelled first on the anatomical images and then matched to the corresponding computed tomography images. The results provide an atlas of the normal cross-sectional and computed tomographic anatomy of the coelomic cavity in the green iguana, the black and white tegu and the bearded dragon, which is useful in the interpretation of any imaging modality. PMID:23410482

  15. Tomographic analysis of the nonthermal x-ray bursts during disruption instability in the T-10 tokamak

    NASA Astrophysics Data System (ADS)

    Savrukhin, P. V.; Ermolaeva, A. I.; Shestakov, E. A.; Khramenkov, A. V.

    2014-10-01

    Non-thermal x-ray radiation (Eγ up to 150 keV) is measured in the T-10 tokamaks during disruption instability using two sets of CdTe detectors (10 vertical and 7 horizontal view detectors). Special narrow cupper tubes collimators with lead screening and CdTe detectors integrated with amplifiers inside metallic containers provides enhanced spatial resolution of the system (r ˜ 3 cm) and assures protection from the parasitic hard x-ray (Eγ up to 1.5 MeV) and electromagnetic loads during disruption. Spatial localization of the nonthermal x-ray emissivity is reconstructed using tomographic Cormack technique with SVD matrix inversion. Analysis indicated appearance of an intensive non-thermal x-ray bursts during initial stage of the disruptions at high density. The bursts are characterized by repetitive spikes (2-3 kHz) of the x-ray emissivity from the plasma core area. Analysis indicated that the spikes can be connected with acceleration of the non-thermal electrons in enhanced longitudinal electric fields induced during energy quench at the disruption instability.

  16. Tomographic analysis of the nonthermal x-ray bursts during disruption instability in the T-10 tokamak

    SciTech Connect

    Savrukhin, P. V.; Ermolaeva, A. I.; Shestakov, E. A.; Khramenkov, A. V.

    2014-10-01

    Non-thermal x-ray radiation (E{sub γ} up to 150 keV) is measured in the T-10 tokamaks during disruption instability using two sets of CdTe detectors (10 vertical and 7 horizontal view detectors). Special narrow cupper tubes collimators with lead screening and CdTe detectors integrated with amplifiers inside metallic containers provides enhanced spatial resolution of the system (r ~ 3 cm) and assures protection from the parasitic hard x-ray (E{sub γ} up to 1.5 MeV) and electromagnetic loads during disruption. Spatial localization of the nonthermal x-ray emissivity is reconstructed using tomographic Cormack technique with SVD matrix inversion. Analysis indicated appearance of an intensive non-thermal x-ray bursts during initial stage of the disruptions at high density. The bursts are characterized by repetitive spikes (2–3 kHz) of the x-ray emissivity from the plasma core area. Analysis indicated that the spikes can be connected with acceleration of the non-thermal electrons in enhanced longitudinal electric fields induced during energy quench at the disruption instability.

  17. Tomographic analysis of neutron and gamma pulse shape distributions from liquid scintillation detectors at Joint European Torus

    SciTech Connect

    Giacomelli, L.; Conroy, S.; Gorini, G.; Horton, L.; Murari, A.; Popovichev, S.; Syme, D. B.

    2014-02-15

    The Joint European Torus (JET, Culham, UK) is the largest tokamak in the world devoted to nuclear fusion experiments of magnetic confined Deuterium (D)/Deuterium-Tritium (DT) plasmas. Neutrons produced in these plasmas are measured using various types of neutron detectors and spectrometers. Two of these instruments on JET make use of organic liquid scintillator detectors. The neutron emission profile monitor implements 19 liquid scintillation counters to detect the 2.45 MeV neutron emission from D plasmas. A new compact neutron spectrometer is operational at JET since 2010 to measure the neutron energy spectra from both D and DT plasmas. Liquid scintillation detectors are sensitive to both neutron and gamma radiation but give light responses of different decay time such that pulse shape discrimination techniques can be applied to identify the neutron contribution of interest from the data. The most common technique consists of integrating the radiation pulse shapes within different ranges of their rising and/or trailing edges. In this article, a step forward in this type of analysis is presented. The method applies a tomographic analysis of the 3-dimensional neutron and gamma pulse shape and pulse height distribution data obtained from liquid scintillation detectors such that n/γ discrimination can be improved to lower energies and additional information can be gained on neutron contributions to the gamma events and vice versa.

  18. Tomographic analysis of neutron and gamma pulse shape distributions from liquid scintillation detectors at Joint European Torus

    NASA Astrophysics Data System (ADS)

    Giacomelli, L.; Conroy, S.; Gorini, G.; Horton, L.; Murari, A.; Popovichev, S.; Syme, D. B.

    2014-02-01

    The Joint European Torus (JET, Culham, UK) is the largest tokamak in the world devoted to nuclear fusion experiments of magnetic confined Deuterium (D)/Deuterium-Tritium (DT) plasmas. Neutrons produced in these plasmas are measured using various types of neutron detectors and spectrometers. Two of these instruments on JET make use of organic liquid scintillator detectors. The neutron emission profile monitor implements 19 liquid scintillation counters to detect the 2.45 MeV neutron emission from D plasmas. A new compact neutron spectrometer is operational at JET since 2010 to measure the neutron energy spectra from both D and DT plasmas. Liquid scintillation detectors are sensitive to both neutron and gamma radiation but give light responses of different decay time such that pulse shape discrimination techniques can be applied to identify the neutron contribution of interest from the data. The most common technique consists of integrating the radiation pulse shapes within different ranges of their rising and/or trailing edges. In this article, a step forward in this type of analysis is presented. The method applies a tomographic analysis of the 3-dimensional neutron and gamma pulse shape and pulse height distribution data obtained from liquid scintillation detectors such that n/γ discrimination can be improved to lower energies and additional information can be gained on neutron contributions to the gamma events and vice versa.

  19. Tomographic analysis of the nonthermal x-ray bursts during disruption instability in the T-10 tokamak.

    PubMed

    Savrukhin, P V; Ermolaeva, A I; Shestakov, E A; Khramenkov, A V

    2014-10-01

    Non-thermal x-ray radiation (Eγ up to 150 keV) is measured in the T-10 tokamaks during disruption instability using two sets of CdTe detectors (10 vertical and 7 horizontal view detectors). Special narrow cupper tubes collimators with lead screening and CdTe detectors integrated with amplifiers inside metallic containers provides enhanced spatial resolution of the system (r ∼ 3 cm) and assures protection from the parasitic hard x-ray (Eγ up to 1.5 MeV) and electromagnetic loads during disruption. Spatial localization of the nonthermal x-ray emissivity is reconstructed using tomographic Cormack technique with SVD matrix inversion. Analysis indicated appearance of an intensive non-thermal x-ray bursts during initial stage of the disruptions at high density. The bursts are characterized by repetitive spikes (2-3 kHz) of the x-ray emissivity from the plasma core area. Analysis indicated that the spikes can be connected with acceleration of the non-thermal electrons in enhanced longitudinal electric fields induced during energy quench at the disruption instability. PMID:25362394

  20. Use of Computed X-ray Tomographic Data for Analyzing the Thermodynamics of a Dissociating Porous Sand/Hydrate Mixture

    DOE R&D Accomplishments Database

    Freifeld, Barry M.; Kneafsey, Timothy J.; Tomutsa, Liviu; Stern, Laura A.; Kirby, Stephen H.

    2002-02-28

    X-ray computed tomography (CT) is a method that has been used extensively in laboratory experiments for measuring rock properties and fluid transport behavior. More recently, CT scanning has been applied successfully to detect the presence and study the behavior of naturally occurring hydrates. In this study, we used a modified medical CT scanner to image and analyze the progression of a dissociation front in a synthetic methane hydrate/sand mixture. The sample was initially scanned under conditions at which the hydrate is stable (atmospheric pressure and liquid nitrogen temperature, 77 K). The end of the sample holder was then exposed to the ambient air, and the core was continuously scanned as dissociation occurred in response to the rising temperature. CT imaging captured the advancing dissociation front clearly and accurately. The evolved gas volume was monitored as a function of time. Measured by CT, the advancing hydrate dissociation front was modeled as a thermal conduction problem explicitly incorporating the enthalpy of dissociation, using the Stefan moving-boundary-value approach. The assumptions needed to perform the analysis consisted of temperatures at the model boundaries. The estimated value for thermal conductivity of 2.6 W/m K for the remaining water ice/sand mixture is higher than expected based on conduction alone; this high value may represent a lumped parameter that incorporates the processes of heat conduction, methane gas convection, and any kinetic effects that occur during dissociation. The technique presented here has broad implications for future laboratory and field testing that incorporates geophysical techniques to monitor gas hydrate dissociation.

  1. Stent sizing strategies in renal artery stenting: the comparison of conventional invasive renal angiography with renal computed tomographic angiography

    PubMed Central

    Michalowska, Ilona; Pregowski, Jerzy; Janaszek-Sitkowska, Hanna; Lech, Katarzyna; Kabat, Marek; Staruch, Adam; Januszewicz, Andrzej; Witkowski, Adam

    2016-01-01

    Introduction Randomized trials comparing invasive treatment of renal artery stenosis with standard pharmacotherapy did not show substantial benefit from revascularization. One of the potential reasons for that may be suboptimal procedure technique. Aim To compare renal stent sizing using two modalities: three-dimensional renal computed tomography angiography (CTA) versus conventional angiography. Material and methods Forty patients (41 renal arteries), aged 65.1 ±8.5 years, who underwent renal artery stenting with preprocedural CTA performed within 6 months, were retrospectively analyzed. In CTA analysis, reference diameter (CTA-D) and lesion length (CTA_LL) were measured and proposed stent diameter and length were recorded. Similarly, angiographic reference diameter (ANGIO_D) and lesion length (ANGIO_LL) as well as proposed stent dimensions were obtained by visual estimation. Results The median CTA_D was 0.5 mm larger than the median ANGIO_D (p < 0.001). Also, the proposed stent diameter in CTA evaluation was 0.5 mm larger than that in angiography (p < 0.0001). The median CTA_LL was 1 mm longer than the ANGIO_LL (p = NS), with significant correlation of these variables (r = 0.66, p < 0.0001). The median proposed stent length with CTA was equal to that proposed with angiography. The median diameter of the implanted stent was 0.5 mm smaller than that proposed in CTA (p < 0.0005) and identical to that proposed in angiography. The median length of the actual stent was longer than that proposed in angiography (p = 0.0001). Conclusions Renal CTA has potential advantages as a tool adjunctive to angiography in appropriate stent sizing. Careful evaluation of the available CTA scans may be beneficial and should be considered prior to the planned procedure. PMID:27279870

  2. Use of computed X-ray tomographic data for analyzing the thermodynamics of a dissociating porous sand/hydrate mixture

    SciTech Connect

    Freifeld, Barry M.; Kneafsey, Timothy J.; Tomutsa, Liviu; Stern, Laura A.; Kirby, Stephen H.

    2002-02-28

    X-ray computed tomography (CT) is a method that has been used extensively in laboratory experiments for measuring rock properties and fluid transport behavior. More recently, CT scanning has been applied successfully to detect the presence and study the behavior of naturally occurring hydrates. In this study, we used a modified medical CT scanner to image and analyze the progression of a dissociation front in a synthetic methane hydrate/sand mixture. The sample was initially scanned under conditions at which the hydrate is stable (atmospheric pressure and liquid nitrogen temperature, 77 K). The end of the sample holder was then exposed to the ambient air, and the core was continuously scanned as dissociation occurred in response to the rising temperature. CT imaging captured the advancing dissociation front clearly and accurately. The evolved gas volume was monitored as a function of time. Measured by CT, the advancing hydrate dissociation front was modeled as a thermal conduction problem explicitly incorporating the enthalpy of dissociation, using the Stefan moving-boundary-value approach. The assumptions needed to perform the analysis consisted of temperatures at the model boundaries. The estimated value for thermal conductivity of 2.6 W/m K for the remaining water ice/sand mixture is higher than expected based on conduction alone; this high value may represent a lumped parameter that incorporates the processes of heat conduction, methane gas convection, and any kinetic effects that occur during dissociation. The technique presented here has broad implications for future laboratory and field testing that incorporates geophysical techniques to monitor gas hydrate dissociation.

  3. Toward a Tomographic Analysis of the Cross-Correlation between Planck CMB Lensing and H-ATLAS Galaxies

    NASA Astrophysics Data System (ADS)

    Bianchini, F.; Lapi, A.; Calabrese, M.; Bielewicz, P.; Gonzalez-Nuevo, J.; Baccigalupi, C.; Danese, L.; de Zotti, G.; Bourne, N.; Cooray, A.; Dunne, L.; Eales, S.; Valiante, E.

    2016-07-01

    We present an improved and extended analysis of the cross-correlation between the map of the cosmic microwave background (CMB) lensing potential derived from the Planck mission data and the high-redshift galaxies detected by the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) in the photometric redshift range {z}{{ph}}≥slant 1.5. We compare the results based on the 2013 and 2015 Planck datasets, and investigate the impact of different selections of the H-ATLAS galaxy samples. Significant improvements over our previous analysis have been achieved thanks to the higher signal-to-noise ratio of the new CMB lensing map recently released by the Planck collaboration. The effective galaxy bias parameter, b, for the full galaxy sample, derived from a joint analysis of the cross-power spectrum and of the galaxy auto-power spectrum is found to be b={3.54}-0.14+0.15. Furthermore, a first tomographic analysis of the cross-correlation signal is implemented by splitting the galaxy sample into two redshift intervals: 1.5≤slant {z}{{ph}}\\lt 2.1 and {z}{{ph}}≥slant 2.1. A statistically significant signal was found for both bins, indicating a substantial increase with redshift of the bias parameter: b=2.89+/- 0.23 for the lower and b={4.75}-0.25+0.24 for the higher redshift bin. Consistent with our previous analysis, we find that the amplitude of the cross-correlation signal is a factor of {1.45}-0.13+0.14 higher than expected from the standard ΛCDM model for the assumed redshift distribution. The robustness of our results against possible systematic effects has been extensively discussed, although the tension is mitigated by passing from 4 to 3σ.

  4. A unique case of Turner syndrome accompanying prolactinoma and unexpected elongated styloid process: Clinical and cone-beam computed tomographic features

    PubMed Central

    Tatli, Ufuk; Yazicioglu, Iffet; Evlice, Ahmet; Oztunc, Haluk

    2013-01-01

    Turner syndrome (TS) is one of the most common chromosomal abnormalities, with an estimated frequency among female live births of 1/2,000-3,000. The syndrome is characterized by the partial or complete absence of one X chromosome (45,X karyotype). We reported a unique case of a 40-year-old woman with TS accompanying unexpected elongated styloid process specific to Eagle syndrome (ES) and followed up-prolactinoma. The present article is the first report to define the cone-beam computed tomographic (CBCT) features of TS accompanying ES. Patients with TS carry various risks that make treatment more complicated; thus advanced imaging techniques for proper treatment and follow-up are extremely important. In the light of CBCT examination, craniofacial abnormalities specific to TS and accompanying syndromes such as the crowding of teeth especially in the maxillary anterior region caused by maxillary narrowness, micrognatic maxilla and mandible, relative mandibular retrusion, malocclusion, open-bite, and an elongated styloid process (length of 32.7 mm) on the right side were illustrated in detail. PMID:23807938

  5. Cone Beam Computed Tomographic Analyses of the Position and Course of the Mandibular Canal: Relevance to the Sagittal Split Ramus Osteotomy

    PubMed Central

    Sekerci, Ahmet Ercan; Sahman, Halil

    2014-01-01

    Purpose. The aim of this study was to document the position and course of the mandibular canal through the region of the mandibular angle and body in dental patients, using cone beam computed tomographic imaging. Methods. The position and course of the mandibular canal from the region of the third molar to the first molar were measured at five specific locations in the same plane: at three different positions just between the first and second molars; between the second and third molars; and just distal to the third molar. Results. The study sample was composed of 500 hemimandibles from 250 dental patients with a mean age of 26.32. Significant differences were found between genders, distances, and positions. B decreased significantly from the anterior positions to the posterior positions in both females and males. The mean values of S and CB increased significantly from the posterior positions to the anterior positions in both females and males. Conclusion. Because the sagittal split ramus osteotomy is a technically difficult procedure, we hope that the findings of the present study will help the surgeon in choosing the safest surgical technique for the treatment of mandibular deformities. PMID:24719896

  6. Diagnosis and follow-up of neonatal tetralogy of Fallot and hemitruncus with discontinuous pulmonary arteries noninvasively using awake ultra low-dose computed tomographic angiography.

    PubMed

    Wheeler, Adam; Vu, Dan; Renella, Pierangelo

    2016-09-01

    We present a case of an ex-30 week premature male infant diagnosed postnatally with Tetralogy of Fallot, hemitruncus, and discontinuous pulmonary arteries (PAs) at 6 days of life. The patient was diagnosed by echocardiography, and the diagnosis was confirmed on subsequent dual-energy chest CT angiogram. In our patient, the left PA arose directly from the aorta, whereas the right PA originated normally from the right ventricular outflow tract. At 9 days of life, he underwent successful surgical palliation with placement of a modified Blalock-Taussig (aortopulmonary) shunt from the base of the left subclavian artery to the anomalously connected left PA along with anastomosis together of the right and left branch PAs to establish continuity with the main PA. Such cases have been described and are rare. The specific aim of this case report is to illustrate the added benefit of dual-energy electrocardiographically-triggered computed tomographic angiography (CTA) along with standard echocardiography. In addition, high quality images useful in preoperative planning were obtained noninvasively using an ultra low radiation dose without the need for sedation. The information obtained proved essential for confirmation of the diagnosis, preoperative planning, and post-surgical monitoring of branch PA development. PMID:27594935

  7. Accompanying artery of sciatic nerve as recipient vessel for free-flap transfer: a computed tomographic angiography study and case reports.

    PubMed

    Miyamoto, Shimpei; Fukunaga, Yutaka; Fujiki, Masahide; Nakatni, Fumihiko; Tanzawa, Yoshikazu; Sakuraba, Minoru

    2015-05-01

    Suitable recipient vessels for free-flap transfer are hard to find in the posterior thigh. To investigate the versatility of accompanying artery of sciatic nerve as a recipient vessel in this region, we performed computed tomographic angiographic study of 20 consecutive healthy thighs in 10 patients. The presence and internal diameter of the accompanying artery were studied. The accompanying artery of the sciatic nerve was present in 11 thighs (55%) and the internal diameter of the artery at the mid-thigh level ranged from 2.1 to 3.2 mm. We used this artery as a recipient vessel for free flaps transferred to reconstruct extensive thigh defects in three patients with sarcomas. In all patients the flaps survived without vascular compromise. No sensory or motor dysfunction in the sciatic nerve distribution occurred in any patients. We believe that the accompanying artery of the sciatic nerve may be a recipient vessel for free-flap transfer in selected patients. PMID:25196891

  8. 3-D volumetric computed tomographic scoring as an objective outcome measure for chronic rhinosinusitis: Clinical correlations and comparison to Lund-Mackay scoring

    PubMed Central

    Pallanch, John; Yu, Lifeng; Delone, David; Robb, Rich; Holmes, David R.; Camp, Jon; Edwards, Phil; McCollough, Cynthia H.; Ponikau, Jens; Dearking, Amy; Lane, John; Primak, Andrew; Shinkle, Aaron; Hagan, John; Frigas, Evangelo; Ocel, Joseph J.; Tombers, Nicole; Siwani, Rizwan; Orme, Nicholas; Reed, Kurtis; Jerath, Nivedita; Dhillon, Robinder; Kita, Hirohito

    2014-01-01

    Background We aimed to test the hypothesis that 3-D volume-based scoring of computed tomographic (CT) images of the paranasal sinuses was superior to Lund-Mackay CT scoring of disease severity in chronic rhinosinusitis (CRS). We determined correlation between changes in CT scores (using each scoring system) with changes in other measures of disease severity (symptoms, endoscopic scoring, and quality of life) in patients with CRS treated with triamcinolone. Methods The study group comprised 48 adult subjects with CRS. Baseline symptoms and quality of life were assessed. Endoscopy and CT scans were performed. Patients received a single systemic dose of intramuscular triamcinolone and were reevaluated 1 month later. Strengths of the correlations between changes in CT scores and changes in CRS signs and symptoms and quality of life were determined. Results We observed some variability in degree of improvement for the different symptom, endoscopic, and quality-of-life parameters after treatment. Improvement of parameters was significantly correlated with improvement in CT disease score using both CT scoring methods. However, volumetric CT scoring had greater correlation with these parameters than Lund-Mackay scoring. Conclusion Volumetric scoring exhibited higher degree of correlation than Lund-Mackay scoring when comparing improvement in CT score with improvement in score for symptoms, endoscopic exam, and quality of life in this group of patients who received beneficial medical treatment for CRS. PMID:24106202

  9. Computed tomographic angiography of the superficial cerebral venous anastomosis based on volume rendering, multi-planar reconstruction, and integral imaging display.

    PubMed

    Fang, Qiong; Chen, Feng; Jiang, Anhong; Huang, Yanping; Deng, Xuefei

    2015-12-01

    As damage to the superficial cerebral venous anastomosis may create catastrophic complications even after successful surgery, it is important to visualize and determine the normal features of the venous anastomosis with computed tomographic angiography. A total of 90 patients underwent a 64-detector row helical CT scan of head. The superficial cerebral venous anastomosis was reconstructed by volume rendering, multi-planar reconstruction, and integral display algorithm. In particular, we examined the vein of Trolard, the vein of Labbe, and the vein of Sylvian, in order to analyze the venous anastomosis. The superficial cerebral venous anastomosis varied across different individuals, and in this study, six types of anastomosis were found. In 28 % of patients, no venous anastomosis was found in the unilateral cerebral hemisphere. The display rate of the vein of Trolard, the vein of Labbe, and the vein of Sylvian in contributing to venous anastomosis was 70, 80, and 91 %, respectively. The number of vein of Trolard and vein of Labbe on the left side was greater than that of those on the right side. We implemented the 64-detector row helical CT as a rapid and noninvasive method to investigate the superficial cerebral venous anastomosis in our group of patients. We performed substantial image processing for the visualization of the superficial cerebral venous anastomosis; this would not only enable the early diagnosis of cerebral venous disease, but also protect the cerebral vein during neurosurgical intervention. PMID:26577709

  10. Comparison of computed tomographic angiography versus rubidium-82 positron emission tomography for the detection of patients with anatomical coronary artery disease

    PubMed Central

    Chow, Benjamin JW; Dennie, Carole; Hoffmann, Udo; So, Derek; deKemp, Robert A; Ruddy, Terrence D; Beanlands, Rob S

    2007-01-01

    BACKGROUND: The present study compared computed tomo-graphic coronary angiography (CTA) and positron emission tomography (PET) for the detection of significant anatomical coronary artery stenosis as defined by conventional invasive coronary angiography (CICA). METHODS: The study protocol was approved by the local ethics board, and informed consent was obtained from all patients. Of the 26 patients (mean age 57±9 years, 18 men) who prospectively underwent CTA and rubidium-82 PET before CICA, 24 patients had a history of chest pain. Images were interpreted by expert readers and assessed for the presence of anatomically significant coronary stenosis (50% luminal diameter stenosis or greater) or myocardial perfusion defects. Diagnostic test characteristics were analyzed using patient-based, territory-based, vessel-based and segment-based analyses. RESULTS: In the 24 patients referred for chest pain, CTA had similar sensitivity to PET, but was more specific (sensitivity 95% [95% CI 72% to 100%] versus 95% [95% CI 72% to 100%], respectively; specificity 100% [95% CI 46% to 100%] versus 60% [95% CI 17% to 93%], respectively) in the detection of patients with anatomical coronary artery stenosis of 50% or greater. On a per-segment basis of all 26 patients, CTA had a sensitivity, specificity, positive predictive value and negative predictive value of 72%, 99%, 91% and 95%, respectively, in all coronary segments. CONCLUSIONS: Coronary CTA has a similar sensitivity and specificity to rubidium-82 PET for the identification of patients with significant anatomical coronary artery disease. PMID:17703259

  11. Intraspinal collateral circulation to the artery of Adamkiewicz detected with intra-arterial injected computed tomographic angiography.

    PubMed

    Domoto, Satoru; Kimura, Fumiko; Asakura, Toshihisa; Nakazawa, Ken; Koike, Hiroyuki; Niinami, Hiroshi

    2016-06-01

    When the intercostal and lumbar arteries are occluded by plaque or thrombus, spinal cord perfusion depends on collateral circulation. Some reports have demonstrated collateral circulation to the artery of Adamkiewicz via computed tomography and magnetic resonance angiographies. However, intraspinal collateral circulation to the artery of Adamkiewicz along the spinal cord has not been reported previously. Here, we report two patients with intraspinal collateral circulation to the artery of Adamkiewicz along the spinal cord that was detected with intra-arterial injected computed tomography angiography. PMID:26365662

  12. Sensitivity analysis in computational aerodynamics

    NASA Technical Reports Server (NTRS)

    Bristow, D. R.

    1984-01-01

    Information on sensitivity analysis in computational aerodynamics is given in outline, graphical, and chart form. The prediction accuracy if the MCAERO program, a perturbation analysis method, is discussed. A procedure for calculating perturbation matrix, baseline wing paneling for perturbation analysis test cases and applications of an inviscid sensitivity matrix are among the topics covered.

  13. COMBINATION OF COMPUTED TOMOGRAPHIC IMAGING CHARACTERISTICS OF MEDIAL RETROPHARYNGEAL LYMPH NODES AND NASAL PASSAGES AIDS DISCRIMINATION BETWEEN RHINITIS AND NEOPLASIA IN CATS.

    PubMed

    Nemanic, Sarah; Hollars, Katelyn; Nelson, Nathan C; Bobe, Gerd

    2015-01-01

    Feline nasal diseases are a diagnostic challenge. The objective of this retrospective, cross-sectional study was to determine whether computed tomography (CT) imaging characteristics of the medial retropharyngeal lymph nodes (MRPLN), alone or in combination with CT imaging characteristics of the nasal passages, could aid in differentiation between rhinitis and nasal neoplasia. Cats were recruited from record archives at two veterinary facilities during the period of 2008-2012. Selection criteria were presentation for chronic nasal discharge, contrast-enhanced CT of the head that included the MRPLN, and rhinoscopic nasal biopsy resulting in diagnosis of rhinitis or neoplasia. For each CT scan, two board-certified veterinary radiologists recorded MRPLN size, attenuation, heterogeneity, contrast-medium enhancement, margination, shape, presence of a lymph node hilus, perinodal fat, turbinate lysis, paranasal bone lysis, and nasal mass. Both readers were unaware of patient information at the time of CT interpretation. Thirty-four cats with rhinitis and 22 cats with neoplasia were included. Computed tomographic characteristics significantly associated with neoplasia included abnormal MRPLN hilus (OR 5.1), paranasal bone lysis (OR 5.6), turbinate lysis (5.6), mass (OR 26.1), MRPLN height asymmetry (OR 4.5), and decreased MRPLN precontrast heterogeneity (OR 7.0). The combined features predictive of neoplasia were a nasal mass with abnormal hilus (OR 47.7); lysis of turbinates/paranasal bones with abnormal MRPLN hilus (OR 16.2). Findings supported the hypothesis that combining CT features of the nasal passages and MRPLN aided in differentiating rhinitis from neoplasia in cats. PMID:26194153

  14. Computer analysis of railcar vibrations

    NASA Technical Reports Server (NTRS)

    Vlaminck, R. R.

    1975-01-01

    Computer models and techniques for calculating railcar vibrations are discussed along with criteria for vehicle ride optimization. The effect on vibration of car body structural dynamics, suspension system parameters, vehicle geometry, and wheel and rail excitation are presented. Ride quality vibration data collected on the state-of-the-art car and standard light rail vehicle is compared to computer predictions. The results show that computer analysis of the vehicle can be performed for relatively low cost in short periods of time. The analysis permits optimization of the design as it progresses and minimizes the possibility of excessive vibration on production vehicles.

  15. Tomographic Analysis of Reactive Flow Induced Pore Structure Changes in Column Experiments

    SciTech Connect

    Cai, Rong; Lindquist, W.Brent; Um, Wooyong; Jones, Keith W.

    2009-09-23

    We utilize synchrotron X-ray computed microtomography to capture and quantify snapshots in time of dissolution and secondary precipitation in the microstructure of Hanford sediments exposed to simulated caustic waste in flow-column experiments. The experiment is complicated somewhat as logis- tics dictated that the column spent significant amounts of time in a sealed state (acting as a batch reactor). Changes accompanying a net reduction in porosity of 4% were quantified including: 1) a 25% net decrease in pores resulting from a 38% loss in the number of pores less than < 10-4 MM3 in volume and a 13% increase in the number of pores of larger size; and 2) a 38% decrease in the number of throats. The loss of throats resulted in de- creased coordination number for pores of all sizes and significant reduction in the number of pore pathways.

  16. Microcomputed tomographic analysis of human condyles in unilateral condylar hyperplasia: increased cortical porosity and trabecular bone volume fraction with reduced mineralisation.

    PubMed

    Karssemakers, L H E; Nolte, J W; Tuinzing, D B; Langenbach, G E J; Raijmakers, P G; Becking, A G

    2014-12-01

    Unilateral condylar hyperplasia or hyperactivity is a disorder of growth that affects the mandible, and our aim was to visualise the 3-dimensional bony microstructure of resected mandibular condyles of affected patients. We prospectively studied 17 patients with a clinical presentation of progressive mandibular asymmetry and an abnormal single-photon emission computed tomographic (SPECT) scan. All patients were treated by condylectomy to arrest progression. The resected condyles were scanned with micro-CT (18 μm resolution). Rectangular volumes of interest were selected in 4 quadrants (lateromedial and superoinferior) of the trabecular bone of each condyle. Variables of bone architecture (volume fraction, trabecular number, thickness, and separation, degree of mineralisation, and degree of structural anisotrophy) were calculated with routine morphometric software. Eight of the 17 resected condyles showed clear destruction of the subchondral layer of cortical bone. There was a significant superoinferior gradient for all trabecular variables. Mean (SD) bone volume fraction (25.1 (6) %), trabecular number (1.69 (0.26) mm(-1)), trabecular thickness (0.17 (0.03) mm), and degree of mineralisation (695.39 (39.83) mg HA/cm(3)) were higher in the superior region. Trabecular separation (0.6 (0.16) mm) and structural anisotropy (1.84 (0.28)) were higher in the inferior region. The micro-CT analysis showed increased cortical porosity in many of the condyles studied. It also showed a higher bone volume fraction, greater trabecular thickness and trabecular separation, greater trabecular number, and less mineralisation in the condyles of the 17 patients compared with the known architecture of unaffected mandibular condyles. PMID:25219775

  17. Use of Coronary Computed Tomographic Angiography Findings to Modify Statin and Aspirin Prescription in Patients With Acute Chest Pain.

    PubMed

    Pursnani, Amit; Celeng, Csilla; Schlett, Christopher L; Mayrhofer, Thomas; Zakroysky, Pearl; Lee, Hang; Ferencik, Maros; Fleg, Jerome L; Bamberg, Fabian; Wiviott, Stephen D; Truong, Quynh A; Udelson, James E; Nagurney, John T; Hoffmann, Udo

    2016-02-01

    Coronary CT angiography (CCTA) is used in patients with low-intermediate chest pain presenting to the emergency department for its reliability in excluding acute coronary syndrome (ACS). However, its influence on medication modification in this setting is unclear. We sought to determine whether knowledge of CCTA-based coronary artery disease (CAD) was associated with change in statin and aspirin prescription. We used the CCTA arm of the Rule Out Myocardial Infarction using Computed Angiographic Tomography II multicenter, randomized control trial (R-II) and comparison cohort from the observational Rule Out Myocardial Infarction using Computed Angiographic Tomography I cohort (R-I). In R-II, subjects were randomly assigned to CCTA to guide decision making, whereas in R-I patients underwent CCTA with results blinded to caregivers and managed according to standard care. Our final cohort consisted of 277 subjects from R-I and 370 from R-II. ACS rate was similar (6.9% vs 6.2% respectively, p = 0.75). For subjects with CCTA-detected obstructive CAD without ACS, initiation of statin was significantly greater after disclosure of CCTA results (0% in R-I vs 20% in R-II, p = 0.009). Conversely, for subjects without CCTA-detected CAD, aspirin prescription was lower with disclosure of CCTA results (16% in R-I vs 4.8% in R-II, p = 0.001). However, only 68% of subjects in R-II with obstructive CAD were discharged on statin and 65% on aspirin. In conclusion, physician knowledge of CCTA results leads to improved alignment of aspirin and statin with the presence and severity of CAD although still many patients with CCTA-detected CAD are not discharged on aspirin or statin. Our findings suggest opportunity for practice improvement when CCTA is performed in the emergency department. PMID:26762723

  18. Mapping of Visual Receptive Fields by Tomographic Reconstruction

    PubMed Central

    Pipa, Gordon; Chen, Zhe; Neuenschwander, Sergio; Lima, Bruss; Brown, Emery N.

    2014-01-01

    The moving bar experiment is a classic paradigm for characterizing the receptive field (RF) properties of neurons in primary visual cortex (V1). Current approaches for analyzing neural spiking activity recorded from these experiments do not take into account the point process nature of these data and the circular geometry of the stimulus presentation. We present a novel analysis approach to mapping V1 receptive fields that combines point process generalized linear models (PPGLM) with tomographic reconstruction computed by filtered-back projection. We use the method to map the RF sizes and orientations of 251 V1 neurons recorded from two macaque monkeys during a moving bar experiment. Our cross-validated goodness-of-fit analyses show that the PPGLM provides a more accurate characterization of spike train data than analyses based on rate functions computed by the methods of spike triggered averages or first-order Wiener-Volterra kernel. Our analysis leads to a new definition of RF size as the spatial area over which the spiking activity is significantly greater than baseline activity. Our approach yields larger RF sizes and sharper orientation tuning estimates. The tomographic reconstruction paradigm further suggests an efficient approach to choosing the number of directions and the number of trials per direction in designing moving bar experiments. Our results demonstrate that standard tomographic principles for image reconstruction can be adapted to characterize V1 RFs and that two fundamental properties, size and orientation, may be substantially different from what is currently reported. PMID:22734491

  19. Validity of Acute Stroke Lesion Volume Estimation by Diffusion-Weighted Imaging–Alberta Stroke Program Early Computed Tomographic Score Depends on Lesion Location in 496 Patients With Middle Cerebral Artery Stroke

    PubMed Central

    Schröder, Julian; Cheng, Bastian; Ebinger, Martin; Köhrmann, Martin; Wu, Ona; Kang, Dong-Wha; Liebeskind, David S.; Tourdias, Thomas; Singer, Oliver C.; Christensen, Soren; Campbell, Bruce; Luby, Marie; Warach, Steven; Fiehler, Jens; Fiebach, Jochen B.; Gerloff, Christian; Thomalla, Götz

    2016-01-01

    Background and Purpose Alberta Stroke Program Early Computed Tomographic Score (ASPECTS) has been used to estimate diffusion-weighted imaging (DWI) lesion volume in acute stroke. We aimed to assess correlations of DWI-ASPECTS with lesion volume in different middle cerebral artery (MCA) subregions and reproduce existing ASPECTS thresholds of a malignant profile defined by lesion volume ≥100 mL. Methods We analyzed data of patients with MCA stroke from a prospective observational study of DWI and fluid-attenuated inversion recovery in acute stroke. DWI-ASPECTS and lesion volume were calculated. The population was divided into subgroups based on lesion localization (superficial MCA territory, deep MCA territory, or both). Correlation of ASPECTS and infarct volume was calculated, and receiver-operating characteristics curve analysis was performed to identify the optimal ASPECTS threshold for ≥100-mL lesion volume. Results A total of 496 patients were included. There was a significant negative correlation between ASPECTS and DWI lesion volume (r=−0.78; P<0.0001). With regards to lesion localization, correlation was weaker in deep MCA region (r=−0.19; P=0.038) when compared with superficial (r=−0.72; P<0.001) or combined superficial and deep MCA lesions (r=−0.72; P<0.001). Receiver-operating characteristics analysis revealed ASPECTS≤6 as best cutoff to identify ≥100-mL DWI lesion volume; however, positive predictive value was low (0.35). Conclusions ASPECTS has limitations when lesion location is not considered. Identification of patients with malignant profile by DWI-ASPECTS may be unreliable. ASPECTS may be a useful tool for the evaluation of noncontrast computed tomography. However, if MRI is used, ASPECTS seems dispensable because lesion volume can easily be quantified on DWI maps. PMID:25316278

  20. Anatomical, radiographical and computed tomographic study of the limbs skeleton of the Euphrates soft shell turtle (Rafetus euphraticus).

    PubMed

    Asadi Ahranjani, Behnaz; Shojaei, Bahador; Tootian, Zahra; Masoudifard, Madjid; Rostami, Amir

    2016-01-01

    Euphrates turtle is the only soft shell turtle of Iran, and unfortunately is in danger of extinction due to multiple reasons. Imaging techniques, in addition to their importance in diagnosis of injuries to animals, have been used as non-invasive methods to provide normal anatomic views. A few studies have been conducted to understand body structure of the Euphrates turtle. Since there is only general information about the anatomy of turtle limbs, the normal skeleton of the Euphrates limbs was studied. For this purpose four adult Euphrates turtles were used. Digital radiographic examination was performed by computed radiographic (CR) in dorsoventral (DV) and lateral (L) positions. Spiral CT-scanning was done and 3D images of the bones were reconstructed for anatomical evaluation. For skeletal preparation, the skeleton was cleaned by a combination of boiling and mealworm methods and limbs' bones were examined anatomically. In the present study, simultaneous anatomic, radiographic and CT studies of bones in individual turtles made us possible to describe bones anatomically and provided comparable and complementary conditions to represent the abilities of the radiography and CT for better understanding of the anatomy. Arrangement and the number of carpal and tarsal bones are used in turtles' classification. Among the studied species, Euphrates turtle carpal and tarsal bones show the most similarities to the Apolone spinifera. PMID:27482356

  1. A Systematic Review of Protocols for the Three-Dimensional Morphologic Assessment of Abdominal Aortic Aneurysms Using Computed Tomographic Angiography

    SciTech Connect

    Ghatwary, Tamer M. H.; Patterson, Benjamin O.; Karthikesalingam, Alan; Hinchliffe, Robert J.; Loftus, Ian M.; Morgan, Robert; Thompson, Matt M.; Holt, Peter J. E.

    2013-02-15

    The morphology of infrarenal abdominal aortic aneurysms (AAAs) directly influences the perioperative outcome and long-term durability of endovascular aneurysm repair. A variety of methods have been proposed for the characterization of AAA morphology using reconstructed three-dimensional (3D) computed tomography (CT) images. At present, there is lack of consensus as to which of these methods is most applicable to clinical practice or research. The purpose of this review was to evaluate existing protocols that used 3D CT images in the assessment of various aspects of AAA morphology. An electronic search was performed, from January 1996 to the end of October 2010, using the Embase and Medline databases. The literature review conformed to PRISMA statement standards. The literature search identified 604 articles, of which 31 studies met inclusion criteria. Only 15 of 31 studies objectively assessed reproducibility. Existing published protocols were insufficient to define a single evidence-based methodology for preoperative assessment of AAA morphology. Further development and expert consensus are required to establish a standardized and validated protocol to determine precisely how morphology relates to outcomes after endovascular aneurysm repair.

  2. Infrared thermography of the pig thorax: an assessment of selected regions of interest by computed tomographical and anatomical parameters.

    PubMed

    Menzel, A; Siewert, C; Gasse, H; Seifert, H; Hoeltig, D; Hennig-Pauka, I

    2015-04-01

    Current methods of diagnosis of respiratory diseases in swine are invasive, time-consuming and expensive. Infrared thermography (IRT) of the thorax might provide a new method of high specificity to select swine affected with lung alterations for further diagnostics. In this study, layer thickness of different tissues was determined in frozen thorax slices (FTS) by computed tomography (CT) and then related to skin temperatures measured by IRT in healthy pigs. The aim was to determine appropriate regions of interest (ROI) for evaluation of IRT images. Organ layer thicknesses measured in CT images correspond to those measured in FTS. Temperature differences between lung ROIs and abdomen ROIs were positively correlated with lung layer thickness at certain localizations, and negatively correlated with the thickness of the thorax wall and of inner organ layers. Reference values of differences between skin temperatures were established for two ROIs on the thorax with potential practical use for lung health status determination. Respective ROIs were located on vertical lines crossing the 7th (right) and the 10th (left) thoracic vertebrae. The presence of ribs affected skin temperature significantly. PMID:24712373

  3. Effects of contrast material on computed tomographic measurements of lung volumes in patients with acute lung injury

    PubMed Central

    Bouhemad, Bélaid; Richecoeur, Jack; Lu, Qin; Malbouisson, Luiz M; Cluzel, Philippe; Rouby, Jean-Jacques

    2003-01-01

    Background Intravenous injection of contrast material is routinely performed in order to differentiate nonaerated lung parenchyma from pleural effusion in critically ill patients undergoing thoracic computed tomography (CT). The aim of the present study was to evaluate the effects of contrast material on CT measurement of lung volumes in 14 patients with acute lung injury. Method A spiral thoracic CT scan, consisting of contiguous axial sections of 10 mm thickness, was performed from the apex to the diaphragm at end-expiration both before and 30 s (group 1; n = 7) or 15 min (group 2; n = 7) after injection of 80 ml contrast material. Volumes of gas and tissue, and volumic distribution of CT attenuations were measured before and after injection using specially designed software (Lungview®; Institut National des Télécommunications, Evry, France). The maximal artifactual increase in lung tissue resulting from a hypothetical leakage within the lung of the 80 ml contrast material was calculated. Results Injection of contrast material significantly increased the apparent volume of lung tissue by 83 ± 57 ml in group 1 and 102 ± 80 ml in group 2, whereas the corresponding maximal artifactual increases in lung tissue were 42 ± 52 ml and 31 ± 18 ml. Conclusion Because systematic injection of contrast material increases the amount of extravascular lung water in patients with acute lung injury, it seems prudent to avoid this procedure in critically ill patients undergoing a thoracic CT scan and to reserve its use for specific indications. PMID:12617742

  4. Computer Tomographic Illustration of the Development of the Pulmonary Function in Bovine Neonates until the Twenty-First Day Postnatum

    PubMed Central

    Bostedt, H.; Richter, A.

    2013-01-01

    The aim of this study was to analyze the development of the lung in newborn calves. The sample consisted of 28 Holstein Friesians calves which were examined clinically, and their chest segment was measured with computed tomography. The tests were performed on the first, sixth, and twelfth hours of life and after the first, second, and third weeks. Also, blood gases and blood counts were determined. Besides Kolmogorov-Smirnov tests, analyses of variance, t-tests (on a significance level of P < 0.05), and correlation analyses were used. The most significant changes occurred between birth and the first hour. However, there were significant differences in the gas filling between cranial and caudal and between dorsal and ventral parenchyma segments. This difference remained over the entire study period. At the end of the first week between 85 and 93% were involved in gas exchange. Only after the completion of the second week of life, the air supply was achieved throughout the whole lung. The pO2, pCO2, and pH values confirmed this. This study shows that a healthy bovine neonate needs about 2 weeks before all lung units are integrated into the gas exchange. This explains why calves in unfavorable environments often suffer from pulmonary affections. PMID:24175112

  5. Quantitative computed tomographic evaluation of femoral bone mineral content in renal osteodystrophy compared with radial photon absorptiometry

    SciTech Connect

    Sakurai, K.; Marumo, F.; Iwanami, S.; Uchida, H.; Matsubayashi, T.

    1989-05-01

    The computed tomography (CT) numbers of cortical bone at the level of 20 cm (CT20) and of spongiosa in the lateral condyle at the level of 2 cm (CT02) from the distal end of the femur were obtained by a quantitative CT method and compared with the bone mineral density of mostly cortical bone within the radius (BMD) by photon absorptiometry. The study included 47 patients with chronic renal failure not dialyzed or induced to regular hemodialysis within 4 weeks of the study (group 1), 28 patients on regular hemodialysis for more than one month (group 2), and ten healthy volunteers (group 3). The measures of bone mineral content (BMC), namely CT20, CT02, and BMD, were compared in terms of their abilities to distinguish members in the various groups. For group 1 and group 3, the greatest variation in BMC was in the difference in CT02, which was primarily a measurement of the BMC of spongiosa. For groups 1 and 2, the greatest variation was in the difference in BMD, which was primarily a measurement of the BMC of cortex. The reproducibility of CT02 was estimated as almost equal to the difference in CT02 values at intervals of 10 months' duration of hemodialysis. The results indicated that CT02 was a useful measurement for evaluating the progress in the early stage of the renal osteodystrophy, and it is recommended that the bone mineral measurement with this QCT method should be performed once or twice a year.

  6. Anatomical, radiographical and computed tomographic study of the limbs skeleton of the Euphrates soft shell turtle (Rafetus euphraticus)

    PubMed Central

    Asadi Ahranjani, Behnaz; Shojaei, Bahador; Tootian, Zahra; Masoudifard, Madjid; Rostami, Amir

    2016-01-01

    Euphrates turtle is the only soft shell turtle of Iran, and unfortunately is in danger of extinction due to multiple reasons. Imaging techniques, in addition to their importance in diagnosis of injuries to animals, have been used as non-invasive methods to provide normal anatomic views. A few studies have been conducted to understand body structure of the Euphrates turtle. Since there is only general information about the anatomy of turtle limbs, the normal skeleton of the Euphrates limbs was studied. For this purpose four adult Euphrates turtles were used. Digital radiographic examination was performed by computed radiographic (CR) in dorsoventral (DV) and lateral (L) positions. Spiral CT-scanning was done and 3D images of the bones were reconstructed for anatomical evaluation. For skeletal preparation, the skeleton was cleaned by a combination of boiling and mealworm methods and limbs’ bones were examined anatomically. In the present study, simultaneous anatomic, radiographic and CT studies of bones in individual turtles made us possible to describe bones anatomically and provided comparable and complementary conditions to represent the abilities of the radiography and CT for better understanding of the anatomy. Arrangement and the number of carpal and tarsal bones are used in turtles’ classification. Among the studied species, Euphrates turtle carpal and tarsal bones show the most similarities to the Apolone spinifera. PMID:27482356

  7. Dual-Source Computed Tomographic Temporal Resolution Provides Higher Image Quality Than 64-Detector Temporal Resolution at Low Heart Rates

    PubMed Central

    Araoz, Philip A.; Kirsch, Jacobo; Primak, Andrew N.; Braun, Natalie N.; Saba, Osama; Williamson, Eric E.; Harmsen, W. Scott; Mandrekar, Jayawant N.; McCollough, Cynthia H.

    2010-01-01

    Objective To compare coronary image quality at temporal resolutions associated with dual-source computed tomography (DSCT; 83 milliseconds) and 64–detector row scanning (165 milliseconds). Methods In 30 patients with a heart rate of less than 70 beats per minute, DSCT coronary angiograms were reconstructed at 83- and 165-millisecond temporal resolutions over different cardiac phases. A blinded observer graded coronary quality. Results The typical DSCT temporal resolution (83 milliseconds) showed a significantly greater quality at end-systole for all coronary vessels and at end-diastole for the right coronary and left anterior descending coronary arteries. For all vessels, the end-diastole produced the highest quality for both temporal resolutions. Conclusions Imaging at 83 milliseconds creates superior quality at end-systole for all coronary vessels and at end-diastole for the right coronary and left anterior descending coronary arteries. At low heart rates, end-diastole produces the highest quality at both temporal resolutions. PMID:20118724

  8. In vivo X-Ray Computed Tomographic Imaging of Soft Tissue with Native, Intravenous, or Oral Contrast

    PubMed Central

    Wathen, Connor A.; Foje, Nathan; van Avermaete, Tony; Miramontes, Bernadette; Chapaman, Sarah E.; Sasser, Todd A.; Kannan, Raghuraman; Gerstler, Steven; Leevy, W. Matthew

    2013-01-01

    X-ray Computed Tomography (CT) is one of the most commonly utilized anatomical imaging modalities for both research and clinical purposes. CT combines high-resolution, three-dimensional data with relatively fast acquisition to provide a solid platform for non-invasive human or specimen imaging. The primary limitation of CT is its inability to distinguish many soft tissues based on native contrast. While bone has high contrast within a CT image due to its material density from calcium phosphate, soft tissue is less dense and many are homogenous in density. This presents a challenge in distinguishing one type of soft tissue from another. A couple exceptions include the lungs as well as fat, both of which have unique densities owing to the presence of air or bulk hydrocarbons, respectively. In order to facilitate X-ray CT imaging of other structures, a range of contrast agents have been developed to selectively identify and visualize the anatomical properties of individual tissues. Most agents incorporate atoms like iodine, gold, or barium because of their ability to absorb X-rays, and thus impart contrast to a given organ system. Here we review the strategies available to visualize lung, fat, brain, kidney, liver, spleen, vasculature, gastrointestinal tract, and liver tissues of living mice using either innate contrast, or commercial injectable or ingestible agents with selective perfusion. Further, we demonstrate how each of these approaches will facilitate the non-invasive, longitudinal, in vivo imaging of pre-clinical disease models at each anatomical site. PMID:23711461

  9. Radiation dose and physical image quality in 128-section dual-source computed tomographic coronary angiography: a phantom study.

    PubMed

    Matsubara, Kosuke; Koshida, Haruka; Sakuta, Keita; Takata, Tadanori; Horii, Junsei; Iida, Hiroji; Koshida, Kichiro; Ichikawa, Katsuhiro; Matsui, Osamu

    2012-01-01

    One-hundred-and-twenty-eight-section dual X-ray source computed tomography (CT) systems have been introduced into clinical practice and have been shown to increase temporal resolution. Higher temporal resolution allows low-dose spiral mode at a high pitch factor during CT coronary angiography. We evaluated radiation dose and physical image qualities in CT coronary angiography by applying high-pitch spiral, step-and-shoot, and low-pitch spiral modes to determine the optimal acquisition mode for clinical situations. An anthropomorphic phantom, small dosimeters, a calibration phantom, and a microdisc phantom were used to evaluate the radiation doses absorbed by thoracic organs, noise power spectrums, in-plane and z-axis modulation transfer functions, slice sensitivity profiles, and number of artifacts for the three acquisition modes. The high-pitch spiral mode had the advantage of a small absorbed radiation dose, but provided low image quality. The low-pitch spiral mode resulted in a high absorbed radiation dose of approximately 200 mGy for the heart. Although the absorbed radiation dose was lower in the step-and-shoot mode than in the low-pitch spiral mode, the noise power spectrum was inferior. The quality of the in-plane modulation transfer function differed, depending on spatial frequency. Therefore, the step-and-shoot mode should be applied initially because of its low absorbed radiation dose and superior image quality. PMID:22955662

  10. A Pilot Evaluation of a 4-Dimensional Cone-Beam Computed Tomographic Scheme Based on Simultaneous Motion Estimation and Image Reconstruction

    SciTech Connect

    Dang, Jun; Gu, Xuejun; Pan, Tinsu; Wang, Jing

    2015-02-01

    Purpose: To evaluate the performance of a 4-dimensional (4-D) cone-beam computed tomographic (CBCT) reconstruction scheme based on simultaneous motion estimation and image reconstruction (SMEIR) through patient studies. Methods and Materials: The SMEIR algorithm contains 2 alternating steps: (1) motion-compensated CBCT reconstruction using projections from all phases to reconstruct a reference phase 4D-CBCT by explicitly considering the motion models between each different phase and (2) estimation of motion models directly from projections by matching the measured projections to the forward projection of the deformed reference phase 4D-CBCT. Four lung cancer patients were scanned for 4 to 6 minutes to obtain approximately 2000 projections for each patient. To evaluate the performance of the SMEIR algorithm on a conventional 1-minute CBCT scan, the number of projections at each phase was reduced by a factor of 5, 8, or 10 for each patient. Then, 4D-CBCTs were reconstructed from the down-sampled projections using Feldkamp-Davis-Kress, total variation (TV) minimization, prior image constrained compressive sensing (PICCS), and SMEIR. Using the 4D-CBCT reconstructed from the fully sampled projections as a reference, the relative error (RE) of reconstructed images, root mean square error (RMSE), and maximum error (MaxE) of estimated tumor positions were analyzed to quantify the performance of the SMEIR algorithm. Results: The SMEIR algorithm can achieve results consistent with the reference 4D-CBCT reconstructed with many more projections per phase. With an average of 30 to 40 projections per phase, the MaxE in tumor position detection is less than 1 mm in SMEIR for all 4 patients. Conclusion: The results from a limited number of patients show that SMEIR is a promising tool for high-quality 4D-CBCT reconstruction and tumor motion modeling.

  11. Protein-Poly(amino acid) Nanocore-Shell Mediated Synthesis of Branched Gold Nanostructures for Computed Tomographic Imaging and Photothermal Therapy of Cancer.

    PubMed

    Sasidharan, Sisini; Bahadur, Dhirendra; Srivastava, Rohit

    2016-06-29

    Anisotropic noble metal nanoparticles especially branched gold nanoparticles with a large absorption cross-section and high molar extinction coefficient have promising applications in biomedical field. However, sophisticated and cumbersome methodologies of synthesis along with toxic precursors pose serious concern for its use. Herein, we report the synthesis of branched gold nanostructures from protein (albumin) nanoparticles by a simple reduction method. Albumin nanoparticles were synthesized by a modified desolvation technique with poly-l-arginine (cationic poly amino acid) substituting the conventional toxic cross-linker, glutaraldehyde. In silico molecular docking was carried out to study the interaction of poly-l-arginine with albumin which revealed its binding to Pocket 1B of the A-chain of albumin. The poly-l-arginine-albumin core-shell nanoparticles of ∼100 nm in size served as a base for attachment of gold ions and its reduction to form 140 nm sized branched gold nanostructures conjugated with glutathione. These gold nanostructures exhibited near-infrared absorption λmax at 800 nm with extreme compatibility toward non cancerous (NIH 3T3), oral epithelial carcinoma (KB) cell lines, and human blood (red blood cells, platelets, and coagulation mechanisms) even up to a high concentration of 250 μg/mL. These structures demonstrated superior computed tomographic (CT) contrast ability and marked photothermal cytotoxicity on KB cells. This study reports for the first time a method to develop blood and cell compatible branched gold nanostructures from protein nanoparticles as a dual CT diagnostic and photothermal therapeutic agent. PMID:27243100

  12. Multiscale tomographic analysis of polymer-nanoparticle hybrid materials for solar cells

    NASA Astrophysics Data System (ADS)

    Lopez-Haro, Miguel; Jiu, Tonggang; Bayle-Guillemaud, Pascale; Jouneau, Pierre-Henri; Chandezon, Frédéric

    2013-10-01

    The present work focuses on the study of the three-dimensional (3D) morphology of polymer and nanoparticle hybrid nanocomposites used as active layers in solution-processed solar cells. The hybrid consists of blends of regioregular poly(3-alkylthiophene) and CdSe nanorods. Electron tomography (ET) analysis performed in high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) allows resolving single nanorods in the hybrid blend. These results are compared with those obtained using focused ion beam coupled with scanning electron microscopy (FIB-SEM), operated in a so-called 3D ``slice-and-view'' mode. This technique allows 3D information to be obtained on a whole device stack (hybrid active layers plus electrodes and the substrate) for significantly larger surface areas than with ET (~10 vs. ~0.1 μm2). The combination of ET and 3D FIB ``slice-and-view'' reconstructions provides complementary and coherent information on the 3D morphology of the hybrid systems at different length scales. Phase separation between the nanoparticles and the polymer is investigated by a quantitative analysis of the reconstructed volumes and is related to the performances of the hybrid devices.The present work focuses on the study of the three-dimensional (3D) morphology of polymer and nanoparticle hybrid nanocomposites used as active layers in solution-processed solar cells. The hybrid consists of blends of regioregular poly(3-alkylthiophene) and CdSe nanorods. Electron tomography (ET) analysis performed in high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) allows resolving single nanorods in the hybrid blend. These results are compared with those obtained using focused ion beam coupled with scanning electron microscopy (FIB-SEM), operated in a so-called 3D ``slice-and-view'' mode. This technique allows 3D information to be obtained on a whole device stack (hybrid active layers plus electrodes and the substrate) for

  13. Tomographic reconstruction for wide-field adaptive optics systems: Fourier domain analysis and fundamental limitations.

    PubMed

    Neichel, Benoit; Fusco, Thierry; Conan, Jean-Marc

    2009-01-01

    Several wide-field-of-view adaptive optics (WFAO) concepts such as multi-conjugate AO (MCAO), multi-object AO (MOAO), and ground-layer AO (GLAO) are currently being studied for the next generation of Extremely Large Telescopes (ELTs). All these concepts will use atmospheric tomography to reconstruct the turbulent-phase volume. In this paper, we explore different reconstruction algorithms and their fundamental limitations, conducting this analysis in the Fourier domain. This approach allows us to derive simple analytical formulations for the different configurations and brings a comprehensive view of WFAO limitations. We then investigate model and statistical errors and their effect on the phase reconstruction. Finally, we show some examples of different WFAO systems and their expected performance on a 42 m telescope case. PMID:19109619

  14. Tomographic analysis for C2 screw placement in rheumatoid arthritis patients

    PubMed Central

    Astolfi, Rodrigo Schroll; Tachibana, Wilson Tadao; Letaif, Olavo Biraghi; Cristante, Alexandre Fogaça; Oliveira, Reginaldo Perilo; de Barros Filho, Tarcísio Eloy Pessoa

    2012-01-01

    Objective A morphological analysis of the bone structure of C2 in patients with rheumatoid arthritis in order to enhance the security of the stabilization procedures for this vertebra. Methods We retrospectively analyzed 20 CT scans of the cervical spine performed in patients with rheumatoid arthritis; the following parameters were measured: spinolaminar angle, thickness and length of C2 lamina. Results The mean values are: 5.92mm and 5.87mm for thickness of right and left laminae retrospectively, 27.75mm for right lamina length and 27.94mm for left lamina length, and 44.7º for spinolaminar angle. Conclusion The values obtained are consistent with studies in normal subjects published by other groups, with no apparent need for change in the screw placement technique. Level of Evidence IV, Case Series. PMID:24453603

  15. Downstream Testing and Subsequent Procedures After Coronary Computed Tomographic Angiography Following Coronary Stenting in Patients ≥65 Years of Age

    PubMed Central

    Mudrick, Daniel; Kaltenbach, Lisa A.; Shah, Bimal; Lytle, Barbara; Masoudi, Frederick A.; Mark, Daniel B.; Federspiel, Jerome J.; Cowper, Patricia A.; Green, Cynthia; Douglas, Pamela S.

    2013-01-01

    Limited data are available on the use of coronary computed tomography angiography (CCTA) in patients who have received percutaneous coronary intervention (PCI). To evaluate patterns of cardiac testing including CCTA after PCI, we created a retrospective observational data set linking the National Cardiovascular Data Registry® CathPCI Registry® baseline data with longitudinal inpatient and outpatient Medicare claims data for patients who received coronary stenting between November 1, 2005 and December 31, 2007. Among 192,009 PCI patients (median age 74 years), the first test after coronary stenting was CCTA for 553 (0.3%), stress testing for 89,900 (46.8%), and coronary angiography for 22,308 (11.6%); 79,248 (41.3%) had no further testing. Patients referred to CCTA first had generally similar or lower baseline risk than those referred for stress testing or catheterization first. Compared to patients with stress testing first after PCI, patients who underwent CCTA first had higher unadjusted rates of subsequent noninvasive testing (10% vs. 3%), catheterization (26% vs. 15%), and revascularization (13% vs. 8%) within 90 days of initial post-PCI testing (p<0.0001 for all). In conclusion, despite similar or lesser risk profiles, patients initially evaluated with CCTA after PCI had more downstream testing and revascularization than patients initially evaluated with stress testing. It is unclear whether these differences derive from patient selection, the performance of CCTA relative to other testing strategies, or the association of early CCTA adoption with distinct patterns of care. PMID:22651883

  16. Evaluation of an X-Ray Dose Profile Derived from an Optically Stimulated Luminescent Dosimeter during Computed Tomographic Fluoroscopy.

    PubMed

    Hasegawa, Hiroaki; Sato, Masanori; Tanaka, Hiroshi

    2015-01-01

    The purpose of this study was to evaluate scatter radiation dose to the subject surface during X-ray computed tomography (CT) fluoroscopy using the integrated dose ratio (IDR) of an X-ray dose profile derived from an optically stimulated luminescent (OSL) dosimeter. We aimed to obtain quantitative evidence supporting the radiation protection methods used during previous CT fluoroscopy. A multislice CT scanner was used to perform this study. OSL dosimeters were placed on the top and the lateral side of the chest phantom so that the longitudinal direction of dosimeters was parallel to the orthogonal axis-to-slice plane for measurement of dose profiles in CT fluoroscopy. Measurement of fluoroscopic conditions was performed at 120 kVp and 80 kVp. Scatter radiation dose was evaluated by calculating the integrated dose determined by OSL dosimetry. The overall percent difference of the integrated doses between OSL dosimeters and ionization chamber was 5.92%. The ratio of the integrated dose of a 100-mm length area to its tails (-50 to -6 mm, 50 to 6 mm) was the lowest on the lateral side at 80 kVp and the highest on the top at 120 kVp. The IDRs for different measurement positions were larger at 120 kVp than at 80 kVp. Similarly, the IDRs for the tube voltage between the primary X-ray beam and scatter radiation was larger on the lateral side than on the top of the phantom. IDR evaluation suggested that the scatter radiation dose has a high dependence on the position and a low dependence on tube voltage relative to the primary X-ray beam for constant dose rate fluoroscopic conditions. These results provided quantitative evidence supporting the radiation protection methods used during CT fluoroscopy in previous studies. PMID:26151914

  17. Phantom and Clinical Study of Differences in Cone Beam Computed Tomographic Registration When Aligned to Maximum and Average Intensity Projection

    SciTech Connect

    Shirai, Kiyonori; Nishiyama, Kinji; Katsuda, Toshizo; Teshima, Teruki; Ueda, Yoshihiro; Miyazaki, Masayoshi; Tsujii, Katsutomo

    2014-01-01

    Purpose: To determine whether maximum or average intensity projection (MIP or AIP, respectively) reconstructed from 4-dimensional computed tomography (4DCT) is preferred for alignment to cone beam CT (CBCT) images in lung stereotactic body radiation therapy. Methods and Materials: Stationary CT and 4DCT images were acquired with a target phantom at the center of motion and moving along the superior–inferior (SI) direction, respectively. Motion profiles were asymmetrical waveforms with amplitudes of 10, 15, and 20 mm and a 4-second cycle. Stationary CBCT and dynamic CBCT images were acquired in the same manner as stationary CT and 4DCT images. Stationary CBCT was aligned to stationary CT, and the couch position was used as the baseline. Dynamic CBCT was aligned to the MIP and AIP of corresponding amplitudes. Registration error was defined as the SI deviation of the couch position from the baseline. In 16 patients with isolated lung lesions, free-breathing CBCT (FBCBCT) was registered to AIP and MIP (64 sessions in total), and the difference in couch shifts was calculated. Results: In the phantom study, registration errors were within 0.1 mm for AIP and 1.5 to 1.8 mm toward the inferior direction for MIP. In the patient study, the difference in the couch shifts (mean, range) was insignificant in the right-left (0.0 mm, ≤1.0 mm) and anterior–posterior (0.0 mm, ≤2.1 mm) directions. In the SI direction, however, the couch position significantly shifted in the inferior direction after MIP registration compared with after AIP registration (mean, −0.6 mm; ranging 1.7 mm to the superior side and 3.5 mm to the inferior side, P=.02). Conclusions: AIP is recommended as the reference image for registration to FBCBCT when target alignment is performed in the presence of asymmetrical respiratory motion, whereas MIP causes systematic target positioning error.

  18. Evaluation of an X-Ray Dose Profile Derived from an Optically Stimulated Luminescent Dosimeter during Computed Tomographic Fluoroscopy

    PubMed Central

    Hasegawa, Hiroaki; Sato, Masanori; Tanaka, Hiroshi

    2015-01-01

    The purpose of this study was to evaluate scatter radiation dose to the subject surface during X-ray computed tomography (CT) fluoroscopy using the integrated dose ratio (IDR) of an X-ray dose profile derived from an optically stimulated luminescent (OSL) dosimeter. We aimed to obtain quantitative evidence supporting the radiation protection methods used during previous CT fluoroscopy. A multislice CT scanner was used to perform this study. OSL dosimeters were placed on the top and the lateral side of the chest phantom so that the longitudinal direction of dosimeters was parallel to the orthogonal axis-to-slice plane for measurement of dose profiles in CT fluoroscopy. Measurement of fluoroscopic conditions was performed at 120 kVp and 80 kVp. Scatter radiation dose was evaluated by calculating the integrated dose determined by OSL dosimetry. The overall percent difference of the integrated doses between OSL dosimeters and ionization chamber was 5.92%. The ratio of the integrated dose of a 100-mm length area to its tails (−50 to −6 mm, 50 to 6 mm) was the lowest on the lateral side at 80 kVp and the highest on the top at 120 kVp. The IDRs for different measurement positions were larger at 120 kVp than at 80 kVp. Similarly, the IDRs for the tube voltage between the primary X-ray beam and scatter radiation was larger on the lateral side than on the top of the phantom. IDR evaluation suggested that the scatter radiation dose has a high dependence on the position and a low dependence on tube voltage relative to the primary X-ray beam for constant dose rate fluoroscopic conditions. These results provided quantitative evidence supporting the radiation protection methods used during CT fluoroscopy in previous studies. PMID:26151914

  19. Comparison of gross and histopathologic findings with quantitative computed tomographic bone density in the distal third metacarpal bone of racehorses.

    PubMed

    Drum, Martha G; Kawcak, Christopher E; Norrdin, Robert W; Park, Richard D; McIlwraith, C Wayne; Les, Clifford M

    2007-01-01

    Comparison of subchondral bone density determined by quantitative computed tomography (CT) with gross and histopathologic changes have not been made in horses. The goal of this study was to determine if mean quantitative CT density and mean voxel standard deviation are associated with the presence and severity of osteochondral lesions in the palmar aspect of the distal third metacarpal bone in racing horses. Metacarpophalangeal joints from nine racehorses were imaged using CT and scored for gross damage. Four-millimeter-thick sagittal and 30 degrees palmar dorsal plane sections were cut, decalcified and stained with hematoxylin and eosin from the distal third metacarpal bone. Microscopic osteochondral lesions and subchondral remodeling were scored on a scale of 0-3. Percent subchondral bone, expressed as the ratio of bone volume to tissue volume, was also measured. Mean quantitative CT density and mean voxel standard deviation were measured from three-dimensional models of CT images comparable with histologic sections. Mean quantitative CT density was not associated with lesion severity or number of lesions. A weak correlation between mean quantitative CT density and gross score was found, but mean quantitative CT density was not predictive for gross score. Mean voxel standard deviation was not correlated with gross or histopathologic measures, but was predictive of mild osteochondral lesions. Results support the association of subchondral remodeling with the development of palmar metacarpal lesions. However, there was not a strong correlation between mean quantitative CT density or mean voxel standard deviation and histopathologic lesions of the distal third metacarpal bone. PMID:18018722

  20. COMPARISON BETWEEN COMPUTED TOMOGRAPHIC CHARACTERISTICS OF THE MIDDLE EAR IN NONBRACHYCEPHALIC AND BRACHYCEPHALIC DOGS WITH OBSTRUCTIVE AIRWAY SYNDROME.

    PubMed

    Salgüero, Raquel; Herrtage, Michael; Holmes, Mark; Mannion, Paddy; Ladlow, Jane

    2016-03-01

    Prevalence of subclinical middle ear lesions in dogs that undergo computed tomography (CT) and magnetic resonance imaging of the head has been reported up to 41%. A predisposition in brachycephalics has been suggested, however evidence-based studies are lacking. Aims of this retrospective cross-sectional study were to compare CT characteristics of the middle ear in groups of nonbrachycephalic and brachycephalic dogs that underwent CT of the head for conditions unrelated to ear disease, and test associations between thickness of the soft palate and presence of subclinical middle ear lesions. One observer recorded CT findings for each dog without knowledge of group status. A total of 65 dogs met inclusion criteria (25 brachycephalic, 40 nonbrachycephalic). Brachycephalic dogs had a significantly thicker bulla wall (P = 2.38 × 10(-26) ) and smaller luminal volume (P = 5.74 × 10(-20) ), when compared to nonbrachycephalic dogs. Soft palate thickness was significantly greater in the brachycephalic group (P = 2.76 × 10(-9) ). Nine of 25 brachycephalic dogs had material in the lumen of the tympanic cavity, compared to zero of 45 of nonbrachycephalics. Within the brachycephalic group, a significant difference in mean soft palate thickness was identified for dogs with material in the middle ear (12.2 mm) vs. air-filled bullae (9 mm; P = 0.016). Findings from the current study supported previous theories that brachycephalic dogs have a greater prevalence of subclinical middle ear effusion and smaller bulla luminal size than nonbrachycephalic dogs. Authors recommend that the bulla lumen volume formula previously developed for mesaticephalic dogs, (-0.612 + 0.757 [lnBW]) be adjusted to 1/3(-0.612 + 0.757 [lnBW]) for brachycephalic breeds. PMID:26765680

  1. DOSIMETRIC CONSEQUENCES OF USING CONTRAST-ENHANCED COMPUTED TOMOGRAPHIC IMAGES FOR INTENSITY-MODULATED STEREOTACTIC BODY RADIOTHERAPY PLANNING.

    PubMed

    Yoshikawa, Hiroto; Roback, Donald M; Larue, Susan M; Nolan, Michael W

    2015-01-01

    Potential benefits of planning radiation therapy on a contrast-enhanced computed tomography scan (ceCT) should be weighed against the possibility that this practice may be associated with an inadvertent risk of overdosing nearby normal tissues. This study investigated the influence of ceCT on intensity-modulated stereotactic body radiotherapy (IM-SBRT) planning. Dogs with head and neck, pelvic, or appendicular tumors were included in this retrospective cross-sectional study. All IM-SBRT plans were constructed on a pre- or ceCT. Contours for tumor and organs at risk (OAR) were manually constructed and copied onto both CT's; IM-SBRT plans were calculated on each CT in a manner that resulted in equal radiation fluence. The maximum and mean doses for OAR, and minimum, maximum, and mean doses for targets were compared. Data were collected from 40 dogs per anatomic site (head and neck, pelvis, and limbs). The average dose difference between minimum, maximum, and mean doses as calculated on pre- and ceCT plans for the gross tumor volume was less than 1% for all anatomic sites. Similarly, the differences between mean and maximum doses for OAR were less than 1%. The difference in dose distribution between plans made on CTs with and without contrast enhancement was tolerable at all treatment sites. Therefore, although caution would be recommended when planning IM-SBRT for tumors near "reservoirs" for contrast media (such as the heart and urinary bladder), findings supported the use of ceCT with this dose calculation algorithm for both target delineation and IM-SBRT treatment planning. PMID:26242716

  2. Comparison of clinical, radiographic, computed tomographic, and magnetic resonance imaging methods for early prediction of canine hip laxity and dysplasia.

    PubMed

    Ginja, Mário M D; Ferreira, António J; Jesus, Sandra S; Melo-Pinto, Pedro; Bulas-Cruz, José; Orden, Maria A; San-Roman, Fidel; Llorens-Pena, Maria P; Gonzalo-Orden, José M

    2009-01-01

    The purpose of the study was to use two palpation methods (Bardens and Ortolani), a radiographic distraction view, three computed tomography (CT) measurements (dorsolateral subluxation score, the lateral center-edge angle, and acetabular ventroversion angle) and two magnetic resonance (MR) imaging hip studies (synovial fluid and acetabular depth indices) in the early monitoring of hip morphology and laxity in 7-9 week old puppies; and in a follow-up study to compare their accuracy in predicting later hip laxity and dysplasia. The MR imaging study was performed with the dog in dorsal recumbency and the CT study with the animal in a weight-bearing position. There was no association between clinical laxity with later hip laxity or dysplasia. The dorsolateral subluxation score and the lateral center-edge angle were characterized by a weak negative correlation with later radiographic passive hip laxity (-0.26 < r < -0.38, P < 0.05) but its association with hip dysplasia was not significant. There was an association between early radiographic passive hip laxity and synovial fluid index with later passive hip laxity (0.41 < r < 0.55, P < 0.05) and this was significantly different in dysplastic vs. nondysplastic hips (P < 0.05). There was no association between the remaining variables and later hip laxity or dysplasia. The overlapping ranges of early passive hip laxity and synovial fluid index for hip dysplasia grades and the moderate correlations with the later passive hip laxity make the results of these variables unreliable for use in predicting hip laxity and dysplasia susceptibility. PMID:19400458

  3. Proximity of the mandibular molar root apex from the buccal bone surface: a cone-beam computed tomographic study

    PubMed Central

    Kim, Dokyung; Jin, Myoung-Uk

    2016-01-01

    Objectives The purpose of this study was to evaluate the proximity of the mandibular molar apex to the buccal bone surface in order to provide anatomic information for apical surgery. Materials and Methods Cone-beam computed tomography (CBCT) images of 127 mandibular first molars and 153 mandibular second molars were analyzed from 160 patients' records. The distance was measured from the buccal bone surface to the root apex and the apical 3.0 mm on the cross-sectional view of CBCT. Results The second molar apex and apical 3 mm were located significantly deeper relative to the buccal bone surface compared with the first molar (p < 0.01). For the mandibular second molars, the distance from the buccal bone surface to the root apex was significantly shorter in patients over 70 years of age (p < 0.05). Furthermore, this distance was significantly shorter when the first molar was missing compared to nonmissing cases (p < 0.05). For the mandibular first molars, the distance to the distal root apex of one distal-rooted tooth was significantly greater than the distance to the disto-buccal root apex (p < 0.01). In mandibular second molar, the distance to the apex of C-shaped roots was significantly greater than the distance to the mesial root apex of non-C-shaped roots (p < 0.01). Conclusions For apical surgery in mandibular molars, the distance from the buccal bone surface to the apex and apical 3 mm is significantly affected by the location, patient age, an adjacent missing anterior tooth, and root configuration. PMID:27508159

  4. The internal cranial morphology of an armoured dinosaur Euoplocephalus corroborated by X-ray computed tomographic reconstruction

    PubMed Central

    Miyashita, Tetsuto; Arbour, Victoria M; Witmer, Lawrence M; Currie, Philip J

    2011-01-01

    Internal cranial anatomy is a challenging area to study in fossilized skulls because of small sample sizes and varied post-mortem preservational alterations. This difficulty has led to the lack of correspondence between results obtained from direct osteological observation and from more indirect reconstruction methods. This paper presents corroborating evidence from direct osteological observation and from reconstruction based on computed X-ray tomography (CT) on the internal cranial anatomy of the ankylosaurid dinosaur Euoplocephalus tutus. A remarkable specimen of Euoplocephalus preserves rarely observed internal cranial structures such as vascular impressions in the nasal cavity, olfactory turbinates and possible impressions of conchae. Comparison with fossils and CT models of other taxa and other Euoplocephalus specimens adds osteological evidence for the previously reconstructed nasal cavity in this dinosaur and revises the previously described braincase morphology. A new interpretation of the ethmoidal homology identifies a mesethmoid, sphenethmoid and ectethmoid. These ethmoidal ossifications are continuous with the mineralized walls of the nasal cavity. The location of the olfactory fenestra provides further evidence that the olfactory regions of the nasal cavity are pushed to the sides of the main airway. This implies that the function of the vascular impressions in the nasal cavity and the looping of the cavity are not related to olfaction. A byproduct of the elongate, looping airway is a dramatic increase in surface area of the nasal respiratory mucosa, which in extant species has been linked to heat and water balance. A role in vocalization as a resonating chamber is another possible function of the looping and elongation of the nasal cavity. Olfaction remains as a possible function for the enlarged olfactory region, suggesting that multiple functions account for different parts of the ankylosaurid nasal cavity that underwent substantial modification

  5. Performance evaluation of principal component analysis for dynamic fluorescence tomographic imaging in measurement space

    NASA Astrophysics Data System (ADS)

    Liu, Xin; He, Xiaowei; Yan, Zhuangzhi

    2015-05-01

    Challenges remain in resolving drug (fluorescent biomarkers) distributions within small animals by fluorescence diffuse optical tomography (FDOT). Principal component analysis (PCA) provides the capability of detecting organs (functional structures) from dynamic FDOT images. However, the resolving performance of PCA may be affected by various experimental factors, e.g., the noise levels in measurement data, the variance in optical properties, the number of acquired frames, and so on. To address the problem, based on a simulation model, we analyze and compare the performance of PCA when applied to three typical sets of experimental conditions (frames number, noise level, and optical properties). The results show that the noise is a critical factor affecting the performance of PCA. When input data containing a low noise (<5%), by a short (e.g., 6 frame) projection sequence, we can resolve the poly(DL-lactic-coglycolic acid)/indocynaine green (PLGA/ICG) distributions in heart and lungs, even though there are great variances in optical properties. In contrast, when 20% Gaussian noise is added to the input data, it hardly resolves the distributions of PLGA/ICG in heart and lungs even though accurate optical properties are used. However, with an increased number of frames, the resolving performance of PCA may gradually recover.

  6. Tomographic Imaging: Visualization of the Unseeable

    NASA Astrophysics Data System (ADS)

    Pan, Xiaochuan

    2009-03-01

    Tomographic imaging is a noninvasive approach to acquiring information within the subject under study, and it plays an increasingly important role in the improvement of health care by providing valuable information for diagnosis of diseases, for guidance of disease treatment and therapy, and for assessment/monitoring of treatment response. It has also found a wide variety of applications in other disciplines, ranging from molecular imaging to material sciences to security scan to paleontology. Over the last 30 years, biomedical imaging has involved into an important discipline in its own right. Physics and mathematics form the foundation of advanced tomographic imaging. Computed tomography (CT) and magnetic resonance imaging (MRI) represent two well-known tomographic imaging modalities. In this talk, I will first introduce the basic physics and mathematics principles on which some of the advanced tomographic imaging techniques such as CT are based, with an emphasis on what and how physical signals are detected, how they are used for producing images, and what physical information is that can be extracted from these images. I will then touch upon some of the recent exciting advances in tomographic imaging technology, followed by a brief discussion of some of the important applications of advanced tomographic imaging in medicine and other areas.

  7. Spatial filtering improved tomographic PIV

    NASA Astrophysics Data System (ADS)

    Discetti, Stefano; Natale, Andrea; Astarita, Tommaso

    2013-04-01

    Tomographic reconstruction accuracy is of fundamental importance to obtain reliable three-dimensional three-components velocity field measurements when implementing tomographic particle image velocimetry. Algebraic methods (Herman and Lent 1976) are quite well established to handle the problem in case of high spatial frequency spots on a dark background imaged by a limited number of simultaneous views; however, their efficacy is limited in case of dense distributions to be reconstructed. In the present work, an easy implementable modified version of the commonly used multiplicative algebraic reconstruction technique is proposed, allowing a remarkable improvement of the tomographic reconstruction quality only slightly increasing the computational cost. The technique is based on artificial diffusion applied by Gaussian smoothing after each iteration of the reconstruction procedure. Numerical simulations show that the increase in the reconstruction quality leads to a significant reduction of the modulation effects in the velocity measurement due to the coherent ghost particles motion. An experimental application in fractal grid turbulence highlights an improvement of the signal strength and a reduction of the uncertainty in the velocity measurement.

  8. Using the technique of computed tomography for nondestructive analysis of pharmaceutical dosage forms

    NASA Astrophysics Data System (ADS)

    de Oliveira, José Martins, Jr.; Mangini, F. Salvador; Carvalho Vila, Marta Maria Duarte; ViníciusChaud, Marco

    2013-05-01

    This work presents an alternative and non-conventional technique for evaluatingof physic-chemical properties of pharmaceutical dosage forms, i.e. we used computed tomography (CT) technique as a nondestructive technique to visualize internal structures of pharmaceuticals dosage forms and to conduct static and dynamical studies. The studies were conducted involving static and dynamic situations through the use of tomographic images, generated by the scanner at University of Sorocaba - Uniso. We have shown that through the use of tomographic images it is possible to conduct studies of porosity, densities, analysis of morphological parameters and performing studies of dissolution. Our results are in agreement with the literature, showing that CT is a powerful tool for use in the pharmaceutical sciences.

  9. Computer vision in microstructural analysis

    NASA Technical Reports Server (NTRS)

    Srinivasan, Malur N.; Massarweh, W.; Hough, C. L.

    1992-01-01

    The following is a laboratory experiment designed to be performed by advanced-high school and beginning-college students. It is hoped that this experiment will create an interest in and further understanding of materials science. The objective of this experiment is to demonstrate that the microstructure of engineered materials is affected by the processing conditions in manufacture, and that it is possible to characterize the microstructure using image analysis with a computer. The principle of computer vision will first be introduced followed by the description of the system developed at Texas A&M University. This in turn will be followed by the description of the experiment to obtain differences in microstructure and the characterization of the microstructure using computer vision.

  10. Comparing the diagnostic accuracy of contrast-enhanced computed tomographic angiography and gadolinium-enhanced magnetic resonance angiography for the assessment of hemodynamically significant transplant renal artery stenosis.

    PubMed

    Gaddikeri, Santhosh; Mitsumori, Lee; Vaidya, Sandeep; Hippe, Daniel S; Bhargava, Puneet; Dighe, Manjiri K

    2014-01-01

    To compare diagnostic accuracy of contrast-enhanced computed tomographic angiography (CTA) and gadolinium-enhanced magnetic resonance angiography (MRA) for the assessment of hemodynamically significant transplant renal artery stenosis (TRAS). After institutional review board approval, records of 27 patients with TRAS confirmed on digital subtraction angiography (DSA) were retrospectively reviewed. A total of 13 patients had MRA and 14 had CTA before DSA. Two board-certified fellowship-trained radiologists, one each from interventional radiology and body imaging blindly reviewed the DSA and CTA or MRA data, respectively. Sensitivity (SN), specificity (SP), positive predictive value, and negative predictive value of MRA and CTA were estimated using 50% stenosis as the detection threshold for significant TRAS. These parameters were compared between modalities using the Fisher exact test. Bias between MRA or CTA imaging and DSA was tested using the Wilcoxon signed-rank test. Two patients were excluded from the MRA group owing to susceptibility artifacts obscuring the TRAS. The correlation between MRA and DSA measurements of stenosis was r = 0.57 (95% CI:-0.02, 0.87; P = 0.052) and between CTA and DSA measurements was r = 0.63 (95% CI: 0.14, 0.87; P = 0.015); the difference between the 2 techniques was not significant (P = 0.7). Both imaging modalities tended to underestimate the degree of stenosis when compared with DSA. MRA group (SN and SP: 56% and 100%, respectively) and CTA group (SN and SP: 81% and 67%, respectively). There were no significant differences in detection performance between modalities (P>0.3 for all measures). We did not find that either modality had any advantage over the other in terms of measuring or detecting significant stenosis. Accordingly, MRA may be preferred over CTA after positive color Doppler ultrasound screening when not contraindicated owing to lack of ionizing radiation or nephrotoxic iodinated contrast. However, susceptibility of

  11. Radiographic and computed tomographic evaluation and gait analysis of Brazilian minipigs with syndactyly.

    PubMed

    Justolin, Pedro L T; Rahal, Sheila C; Agostinho, Felipe S; Mamprim, Maria J; Teixeira, Carlos R; Doiche, Danuta P; Babicsak, Vivian R

    2016-09-01

    OBJECTIVE To characterize a population of Brazilian minipigs with naturally occurring syndactyly by use of plain radiographs and CT images and to evaluate kinetic and temporospatial variables by use of a pressure-sensing walkway. ANIMALS 10 Brazilian minipigs from 6 to 8 months of age (group 1, 5 healthy pigs [body weight, 10.5 to 18.5 kg]; group 2, 5 pigs with syndactyly [body weight, 7.5 to 18.0 kg]). PROCEDURES Forelimbs and hind limbs of all pigs were assessed by use of radiography and CT. Gait was analyzed by use of a pressure-sensing walkway. RESULTS All limbs of all pigs of group 2 had syndactyly. Two forelimbs had complex-1 syndactyly, and 8 forelimbs had complex-2 syndactyly. Four hind limbs had simple syndactyly, 1 hind limb had complex-1 syndactyly, and 5 hind limbs had complex-2 syndactyly. Kinetic and temporospatial values and symmetry indices did not differ between groups. Plantar and palmar surfaces of healthy pigs had 2 areas of maximum pressure, whereas plantar and palmar surfaces of pigs with syndactyly had only 1 area of maximum pressure. CONCLUSIONS AND CLINICAL RELEVANCE In this population of pigs, the most common type of syndactyly was complex-2, and comparison with the healthy group revealed no alteration in kinetic and temporospatial variables. Therefore, results suggested that syndactyly in young minipigs did not cause locomotor disturbances. PMID:27580109

  12. Coronary dominance and prognosis in patients undergoing coronary computed tomographic angiography: results from the CONFIRM (COronary CT Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multicenter) registry

    PubMed Central

    Gebhard, Catherine; Fuchs, Tobias A.; Stehli, Julia; Gransar, Heidi; Berman, Daniel S.; Budoff, Matthew J.; Achenbach, Stephan; Al-Mallah, Mouaz; Andreini, Daniele; Cademartiri, Filippo; Callister, Tracy Q.; Chang, Hyuk-Jae; Chinnaiyan, Kavitha M.; Chow, Benjamin J. W.; Cury, Ricardo C.; Delago, Augustin; Gomez, Millie J.; Hadamitzky, Martin; Hausleiter, Joerg; Hindoyan, Niree; Feuchtner, Gudrun; Kim, Yong-Jin; Leipsic, Jonathon; Lin, Fay Y.; Maffei, Erica; Pontone, Gianluca; Raff, Gilbert; Shaw, Leslee J.; Villines, Todd C.; Dunning, Allison M.; Min, James K.; Kaufmann, Philipp A.

    2015-01-01

    Aims Coronary computed tomographic angiography (CCTA) has become an important tool for non-invasive diagnosis of coronary artery disease (CAD). Coronary dominance can be assessed by CCTA; however, the predictive value of coronary dominance is controversially discussed. The aim of this study was to evaluate the prevalence and prognosis of coronary dominance in a large prospective, international multicentre cohort of patients undergoing CCTA. Methods and results The study population consisted of 6382 patients with or without CAD (47% females, 53% males, mean age 56.9 ± 12.3 years) who underwent CCTA and were followed over a period of 60 months. Right or left coronary dominance was determined. Right dominance was present in 91% (n = 5817) and left in 9% (n = 565) of the study population. At the end of follow-up, outcome in patients with obstructive CAD (>50% luminal stenosis) and right dominance was similar compared with patients with left dominance [hazard ratio (HR) 0.46, 95% CI 0.16–1.32, P = 0.15]. Furthermore, no differences were observed for the type of coronary dominance in patients with non-obstructive CAD (HR 0.95, 95% CI 0.41–2.21, P = 0.8962) or normal coronary arteries (HR 1.04, 95% CI 0.68–1.59, P = 0.9). Subgroup analysis in patients with left main disease revealed an elevated hazard of the combined endpoint for left dominance (HR 6.45, 95% CI 1.66–25.0, P = 0.007), but not for right dominance. Conclusion In our study population, survival after 5 years of follow-up did not differ significantly between patients with left or right coronary dominance. Thus, assessment of coronary vessel dominance by CCTA may not enhance risk stratification in patients with normal coronary arteries or obstructive CAD, but may add prognostic information for specific subpopulations. PMID:25744341

  13. Analysis of distortions in the velocity profiles of suspension flows inside a light-scattering medium upon their reconstruction from the optical coherence Doppler tomograph signal

    SciTech Connect

    Bykov, A V; Kirillin, M Yu; Priezzhev, A V

    2005-11-30

    Model signals from one and two plane flows of a particle suspension are obtained for an optical coherence Doppler tomograph (OCDT) by the Monte-Carlo method. The optical properties of particles mimic the properties of non-aggregating erythrocytes. The flows are considered in a stationary scattering medium with optical properties close to those of the skin. It is shown that, as the flow position depth increases, the flow velocity determined from the OCDT signal becomes smaller than the specified velocity and the reconstructed profile extends in the direction of the distant boundary, which is accompanied by the shift of its maximum. In the case of two flows, an increase in the velocity of the near-surface flow leads to the overestimated values of velocity of the reconstructed profile of the second flow. Numerical simulations were performed by using a multiprocessor parallel-architecture computer. (laser applications in medicine)

  14. Forensic Analysis of Compromised Computers

    NASA Technical Reports Server (NTRS)

    Wolfe, Thomas

    2004-01-01

    Directory Tree Analysis File Generator is a Practical Extraction and Reporting Language (PERL) script that simplifies and automates the collection of information for forensic analysis of compromised computer systems. During such an analysis, it is sometimes necessary to collect and analyze information about files on a specific directory tree. Directory Tree Analysis File Generator collects information of this type (except information about directories) and writes it to a text file. In particular, the script asks the user for the root of the directory tree to be processed, the name of the output file, and the number of subtree levels to process. The script then processes the directory tree and puts out the aforementioned text file. The format of the text file is designed to enable the submission of the file as input to a spreadsheet program, wherein the forensic analysis is performed. The analysis usually consists of sorting files and examination of such characteristics of files as ownership, time of creation, and time of most recent access, all of which characteristics are among the data included in the text file.

  15. Tomographic imaging in civil engineering infrastructure

    NASA Astrophysics Data System (ADS)

    Gheshlaghi, Farshad

    help the selection of proper constraints. Distribution and amount of information, presence of accidental and systematic errors, degree of heterogeneity and anisotropy, and analysis of shadows are analyzed for all case histories. A tomographic program based on sparse matrix algorithms was encoded as part of this study. The selected tomographic inversion methods are based on matrix analyses. Data structures are used to take advantage of the sparsity of the coefficient matrix and to avoid high memory and computational demand. Sine-arc ray tracing and straight rays are two possibilities. Tomographic data are usually mixed-determined and ill-conditioned. Damped Least squares (DLSQ) and regularization add information in the form of constraints in order to decrease the ill-conditioning of the problem. The optimum damping or regularization coefficient gives the best solution. Optimal damping or regularization coefficients should be determined in an inversion process. (Abstract shortened by UMI.)

  16. Scanning tomographic acoustic microscopy

    NASA Astrophysics Data System (ADS)

    Lee, Hua

    2002-11-01

    This paper provides an overview of the design and development of the scanning tomographic acoustic microscopy (STAM). This research effort spans over a period of more than 12 years, which successfully elevated the acoustic microscopy from the traditional intensity-mapping mode to the level of holographic and tomographic imaging. The tomographic imaging capability of STAM was developed on the platform of the scanning laser acoustic microscope (SLAM), which operates in a coherent transmission mode with plane-wave illumination and scanning laser wavefield detection. The image formation techniques were based on the backward propagation method implemented in the plane-to-plane format. In this paper, the key elements of the design and development, including the modification of the data-acquisition hardware, implementation of image reconstruction algorithms for multiple-frequency and multiple-angle tomography, and the high-precision phase-correction and image registration techniques for the superposition of coherent sub-images, will be discussed. Results of full-scale experiments will also be included to demonstrate the capability of holographic and tomographic image formation in microscopic scale.

  17. Homogenized Tomographic Models: a Tool for Efficient Numerical Modeling of Seismic Wave Propagation

    NASA Astrophysics Data System (ADS)

    Landes, M.; Capdeville, Y.; Shapiro, N.; Guilbert, J.

    2013-12-01

    Full seismic waveforms are frequently used to characterize details of seismic sources and to discriminate their origin. Prediction of realistic waveforms requires developing algorithms for fast and reliable simulation of seismic wave propagation in 3D models of Earth. Classical 3D seismic tomographic models often use a layered parameterization. However, computing exact wave propagation in layered models may result in mesh complexity and long computing time. These difficulties become crucial when considering regional scales with operational interests. The aim of our study is to develop a parameterization of seismic tomographic models adapted for efficient numerical modeling of the wave propagation within a given frequency range. We use a 'homogenization' approach to construct models smoothed at scale naturally imposed by their propagation characteristics at target frequencies. We start with defining a basis of continuous and smooth functions with a Principal Component Analysis based on the statistic of the homogenized CUB2 tomographic model. Then, we invert surface phase and the group velocities deduced from global tomographic maps with a Monte Carlo method to generate smooth depth profiles with a controlled number of unknowns at all grid points. The set of these profiles form a smooth 3D seismic velocity model designed for numerical wave propagation.

  18. A Petaflops Era Computing Analysis

    NASA Technical Reports Server (NTRS)

    Preston, Frank S.

    1998-01-01

    This report covers a study of the potential for petaflops (1O(exp 15) floating point operations per second) computing. This study was performed within the year 1996 and should be considered as the first step in an on-going effort. 'Me analysis concludes that a petaflop system is technically feasible but not feasible with today's state-of-the-art. Since the computer arena is now a commodity business, most experts expect that a petaflops system will evolve from current technology in an evolutionary fashion. To meet the price expectations of users waiting for petaflop performance, great improvements in lowering component costs will be required. Lower power consumption is also a must. The present rate of progress in improved performance places the date of introduction of petaflop systems at about 2010. Several years before that date, it is projected that the resolution limit of chips will reach the now known resolution limit. Aside from the economic problems and constraints, software is identified as the major problem. The tone of this initial study is more pessimistic than most of the Super-published material available on petaflop systems. Workers in the field are expected to generate more data which could serve to provide a basis for a more informed projection. This report includes an annotated bibliography.

  19. Computer analysis of cardiovascular parameters.

    PubMed

    Mass, H J; Gean, J T; Gwirtz, P A

    1987-01-01

    A computer program is described for the analysis of several cardiovascular parameters frequently measured or derived in the chronically instrumented dog model. Data are stored on magnetic tape and are subsequently analyzed with the Apple IIe microcomputer equipped with the ADALAB (Interactive Microware, Inc.) analog-to-digital convertor. Not limited to the chronically instrumented animal model, the program is capable of analyzing left ventricular pressure, three channels of regional myocardial segment length, coronary flow velocity as measured by the Doppler ultrasonic flow technique, and two channels of systemic arterial pressure. Derived data include: left ventricular dP/dtmax, left ventricular pressure-heart rate product, left ventricular ejection time, tension time index; percent segment length shortening and velocity of shortening, dL/dt(s)max, regional stroke work and power, duration of systole and diastole; mean coronary flow velocity, peak diastolic and systolic flow velocity, and true mean systemic arterial pressure. PMID:3581809

  20. Relationship between lung function and quantitative computed tomographic parameters of airway remodeling, air trapping, and emphysema in patients with asthma and chronic obstructive pulmonary disease: A single-center study

    PubMed Central

    Hartley, Ruth A.; Barker, Bethan L.; Newby, Chris; Pakkal, Mini; Baldi, Simonetta; Kajekar, Radhika; Kay, Richard; Laurencin, Marie; Marshall, Richard P.; Sousa, Ana R.; Parmar, Harsukh; Siddiqui, Salman; Gupta, Sumit; Brightling, Chris E.

    2016-01-01

    Background There is a paucity of studies comparing asthma and chronic obstructive pulmonary disease (COPD) based on thoracic quantitative computed tomographic (QCT) parameters. Objectives We sought to compare QCT parameters of airway remodeling, air trapping, and emphysema between asthmatic patients and patients with COPD and explore their relationship with airflow limitation. Methods Asthmatic patients (n = 171), patients with COPD (n = 81), and healthy subjects (n = 49) recruited from a single center underwent QCT and clinical characterization. Results Proximal airway percentage wall area (%WA) was significantly increased in asthmatic patients (62.5% [SD, 2.2]) and patients with COPD (62.7% [SD, 2.3]) compared with that in healthy control subjects (60.3% [SD, 2.2], P < .001). Air trapping measured based on mean lung density expiratory/inspiratory ratio was significantly increased in patients with COPD (mean, 0.922 [SD, 0.037]) and asthmatic patients (mean, 0.852 [SD, 0.061]) compared with that in healthy subjects (mean, 0.816 [SD, 0.066], P < .001). Emphysema assessed based on lung density measured by using Hounsfield units below which 15% of the voxels lie (Perc15) was a feature of COPD only (patients with COPD: mean, −964 [SD, 19.62] vs asthmatic patients: mean, −937 [SD, 22.7] and healthy subjects: mean, −937 [SD, 17.1], P < .001). Multiple regression analyses showed that the strongest predictor of lung function impairment in asthmatic patients was %WA, whereas in the COPD and asthma subgrouped with postbronchodilator FEV1 percent predicted value of less than 80%, it was air trapping. Factor analysis of QCT parameters in asthmatic patients and patients with COPD combined determined 3 components, with %WA, air trapping, and Perc15 values being the highest loading factors. Cluster analysis identified 3 clusters with mild, moderate, or severe lung function impairment with corresponding decreased lung density (Perc15 values) and increased air

  1. Computed tomographic colonography compared with colonoscopy or barium enema for diagnosis of colorectal cancer in older symptomatic patients: two multicentre randomised trials with economic evaluation (the SIGGAR trials).

    PubMed Central

    Halligan, Steve; Dadswell, Edward; Wooldrage, Kate; Wardle, Jane; von Wagner, Christian; Lilford, Richard; Yao, Guiqing L; Zhu, Shihua; Atkin, Wendy

    2015-01-01

    BACKGROUND Computed tomographic colonography (CTC) is a relatively new diagnostic test that may be superior to existing alternatives to investigate the large bowel. OBJECTIVES To compare the diagnostic efficacy, acceptability, safety and cost-effectiveness of CTC with barium enema (BE) or colonoscopy. DESIGN Parallel randomised trials: BE compared with CTC and colonoscopy compared with CTC (randomisation 2 : 1, respectively). SETTING A total of 21 NHS hospitals. PARTICIPANTS Patients aged ≥ 55 years with symptoms suggestive of colorectal cancer (CRC). INTERVENTIONS CTC, BE and colonoscopy. MAIN OUTCOME MEASURES For the trial of CTC compared with BE, the primary outcome was the detection rate of CRC and large polyps (≥ 10 mm), with the proportion of patients referred for additional colonic investigation as a secondary outcome. For the trial of CTC compared with colonoscopy, the primary outcome was the proportion of patients referred for additional colonic investigation, with the detection rate of CRC and large polyps as a secondary outcome. Secondary outcomes for both trials were miss rates for cancer (via registry data), all-cause mortality, serious adverse events, patient acceptability, extracolonic pathology and cost-effectiveness. RESULTS A total of 8484 patients were registered and 5384 were randomised and analysed (BE trial: 2527 BE, 1277 CTC; colonoscopy trial: 1047 colonoscopy, 533 CTC). Detection rates in the BE trial were 7.3% (93/1277) for CTC, compared with 5.6% (141/2527) for BE (p = 0.0390). The difference was due to better detection of large polyps by CTC (3.6% vs. 2.2%; p = 0.0098), with no significant difference for cancer (3.7% vs. 3.4%; p = 0.66). Significantly more patients having CTC underwent additional investigation (23.5% vs. 18.3%; p = 0.0003). At the 3-year follow-up, the miss rate for CRC was 6.7% for CTC (three missed cancers) and 14.1% for BE (12 missed cancers). Significantly more patients randomised to CTC

  2. Corneal Segmentation Analysis Increases Glaucoma Diagnostic Ability of Optic Nerve Head Examination, Heidelberg Retina Tomograph's Moorfield's Regression Analysis, and Glaucoma Probability Score

    PubMed Central

    Saenz-Frances, F.; Jañez, L.; Berrozpe-Villabona, C.; Borrego-Sanz, L.; Morales-Fernández, L.; Acebal-Montero, A.; Mendez-Hernandez, C. D.; Martinez-de-la-Casa, J. M.; Santos-Bueso, E.; Garcia-Sanchez, J.; Garcia-Feijoo, J.

    2015-01-01

    Purpose. To study whether a corneal thickness segmentation model, consisting in a central circular zone of 1 mm radius centered at the corneal apex (zone I) and five concentric rings of 1 mm width (moving outwards: zones II to VI), could boost the diagnostic accuracy of Heidelberg Retina Tomograph's (HRT's) MRA and GPS. Material and Methods. Cross-sectional study. 121 healthy volunteers and 125 patients with primary open-angle glaucoma. Six binary multivariate logistic regression models were constructed (MOD-A1, MOD-A2, MOD-B1, MOD-B2, MOD-C1, and MOD-C2). The dependent variable was the presence of glaucoma. In MOD-A1, the predictor was the result (presence of glaucoma) of the analysis of the stereophotography of the optic nerve head (ONH). In MOD-B1 and MOD-C1, the predictor was the result of the MRA and GPS, respectively. In MOD-B2 and MOD-C2, the predictors were the same along with corneal variables: central, overall, and zones I to VI thicknesses. This scheme was reproduced for model MOD-A2 (stereophotography along with corneal variables). Models were compared using the area under the receiver operator characteristic curve (AUC). Results. MOD-A1-AUC: 0.771; MOD-A2-AUC: 0.88; MOD-B1-AUC: 0.736; MOD-B2-AUC: 0.845; MOD-C1-AUC: 0.712; MOD-C2-AUC: 0.838. Conclusion. Corneal thickness variables enhance ONH assessment and HRT's MRA and GPS diagnostic capacity. PMID:26180641

  3. Personal Computer Transport Analysis Program

    NASA Technical Reports Server (NTRS)

    DiStefano, Frank, III; Wobick, Craig; Chapman, Kirt; McCloud, Peter

    2012-01-01

    The Personal Computer Transport Analysis Program (PCTAP) is C++ software used for analysis of thermal fluid systems. The program predicts thermal fluid system and component transients. The output consists of temperatures, flow rates, pressures, delta pressures, tank quantities, and gas quantities in the air, along with air scrubbing component performance. PCTAP s solution process assumes that the tubes in the system are well insulated so that only the heat transfer between fluid and tube wall and between adjacent tubes is modeled. The system described in the model file is broken down into its individual components; i.e., tubes, cold plates, heat exchangers, etc. A solution vector is built from the components and a flow is then simulated with fluid being transferred from one component to the next. The solution vector of components in the model file is built at the initiation of the run. This solution vector is simply a list of components in the order of their inlet dependency on other components. The component parameters are updated in the order in which they appear in the list at every time step. Once the solution vectors have been determined, PCTAP cycles through the components in the solution vector, executing their outlet function for each time-step increment.

  4. Computer graphics in aerodynamic analysis

    NASA Technical Reports Server (NTRS)

    Cozzolongo, J. V.

    1984-01-01

    The use of computer graphics and its application to aerodynamic analyses on a routine basis is outlined. The mathematical modelling of the aircraft geometries and the shading technique implemented are discussed. Examples of computer graphics used to display aerodynamic flow field data and aircraft geometries are shown. A future need in computer graphics for aerodynamic analyses is addressed.

  5. Partially coherent lensfree tomographic microscopy⋄

    PubMed Central

    Isikman, Serhan O.; Bishara, Waheb; Ozcan, Aydogan

    2012-01-01

    Optical sectioning of biological specimens provides detailed volumetric information regarding their internal structure. To provide a complementary approach to existing three-dimensional (3D) microscopy modalities, we have recently demonstrated lensfree optical tomography that offers high-throughput imaging within a compact and simple platform. In this approach, in-line holograms of objects at different angles of partially coherent illumination are recorded using a digital sensor-array, which enables computing pixel super-resolved tomographic images of the specimen. This imaging modality, which forms the focus of this review, offers micrometer-scale 3D resolution over large imaging volumes of, for example, 10–15 mm3, and can be assembled in light weight and compact architectures. Therefore, lensfree optical tomography might be particularly useful for lab-on-a-chip applications as well as for microscopy needs in resource-limited settings. PMID:22193016

  6. Kinky tomographic reconstruction

    SciTech Connect

    Hanson, K.M.; Cunningham, G.S.; Bilisoly, R.L.

    1996-05-01

    We address the issue of how to make decisions about the degree of smoothness demanded of a flexible contour used to model the boundary of a 2D object. We demonstrate the use of a Bayesian approach to set the strength of the smoothness prior for a tomographic reconstruction problem. The Akaike Information Criterion is used to determine whether to allow a kink in the contour.

  7. Field-portable lensfree tomographic microscope†

    PubMed Central

    Isikman, Serhan O.; Bishara, Waheb; Sikora, Uzair; Yaglidere, Oguzhan; Yeah, John; Ozcan, Aydogan

    2011-01-01

    We present a field-portable lensfree tomographic microscope, which can achieve sectional imaging of a large volume (~20 mm3) on a chip with an axial resolution of <7 μm. In this compact tomographic imaging platform (weighing only ~110 grams), 24 light-emitting diodes (LEDs) that are each butt-coupled to a fibre-optic waveguide are controlled through a cost-effective micro-processor to sequentially illuminate the sample from different angles to record lensfree holograms of the sample that is placed on the top of a digital sensor array. In order to generate pixel super-resolved (SR) lensfree holograms and hence digitally improve the achievable lateral resolution, multiple sub-pixel shifted holograms are recorded at each illumination angle by electromagnetically actuating the fibre-optic waveguides using compact coils and magnets. These SR projection holograms obtained over an angular range of ~50° are rapidly reconstructed to yield projection images of the sample, which can then be back-projected to compute tomograms of the objects on the sensor-chip. The performance of this compact and light-weight lensfree tomographic microscope is validated by imaging micro-beads of different dimensions as well as a Hymenolepis nana egg, which is an infectious parasitic flatworm. Achieving a decent three-dimensional spatial resolution, this field-portable on-chip optical tomographic microscope might provide a useful toolset for telemedicine and high-throughput imaging applications in resource-poor settings. PMID:21573311

  8. Grid computing in image analysis

    PubMed Central

    2011-01-01

    Diagnostic surgical pathology or tissue–based diagnosis still remains the most reliable and specific diagnostic medical procedure. The development of whole slide scanners permits the creation of virtual slides and to work on so-called virtual microscopes. In addition to interactive work on virtual slides approaches have been reported that introduce automated virtual microscopy, which is composed of several tools focusing on quite different tasks. These include evaluation of image quality and image standardization, analysis of potential useful thresholds for object detection and identification (segmentation), dynamic segmentation procedures, adjustable magnification to optimize feature extraction, and texture analysis including image transformation and evaluation of elementary primitives. Grid technology seems to possess all features to efficiently target and control the specific tasks of image information and detection in order to obtain a detailed and accurate diagnosis. Grid technology is based upon so-called nodes that are linked together and share certain communication rules in using open standards. Their number and functionality can vary according to the needs of a specific user at a given point in time. When implementing automated virtual microscopy with Grid technology, all of the five different Grid functions have to be taken into account, namely 1) computation services, 2) data services, 3) application services, 4) information services, and 5) knowledge services. Although all mandatory tools of automated virtual microscopy can be implemented in a closed or standardized open system, Grid technology offers a new dimension to acquire, detect, classify, and distribute medical image information, and to assure quality in tissue–based diagnosis. PMID:21516880

  9. Fixture-abutment connection surface and micro-gap measurements by 3D micro-tomographic technique analysis.

    PubMed

    Meleo, Deborah; Baggi, Luigi; Di Girolamo, Michele; Di Carlo, Fabio; Pecci, Raffaella; Bedini, Rossella

    2012-01-01

    X-ray micro-tomography (micro-CT) is a miniaturized form of conventional computed axial tomography (CAT) able to investigate small radio-opaque objects at a-few-microns high resolution, in a non-destructive, non-invasive, and tri-dimensional way. Compared to traditional optical and electron microscopy techniques, which provide two-dimensional images, this innovative investigation technology enables a sample tri-dimensional analysis without cutting, coating or exposing the object to any particular chemical treatment. X-ray micro-tomography matches ideal 3D microscopy features: the possibility of investigating an object in natural conditions and without any preparation or alteration; non-invasive, non-destructive, and sufficiently magnified 3D reconstruction; reliable measurement of numeric data of the internal structure (morphology, structure and ultra-structure). Hence, this technique has multi-fold applications in a wide range of fields, not only in medical and odontostomatologic areas, but also in biomedical engineering, materials science, biology, electronics, geology, archaeology, oil industry, and semi-conductors industry. This study shows possible applications of micro-CT in dental implantology to analyze 3D micro-features of dental implant to abutment interface. Indeed, implant-abutment misfit is known to increase mechanical stress on connection structures and surrounding bone tissue. This condition may cause not only screw preload loss or screw fracture, but also biological issues in peri-implant tissues. PMID:22456016

  10. Tomographic /sup 67/Ga citrate scanning: useful new surveillance for metastatic melanoma

    SciTech Connect

    Kirkwood, J.M.; Myers, J.E.; Vlock, D.R.; Neumann, R.; Ariyan, S.; Gottschalk, A.; Hoffer, P.

    1982-11-01

    Conventional gallium scans are not useful to evaluate patients with metastatic melanoma. We evaluated a new method of tomographic gallium imaging. One hundred fourteen tomographic scans were obtained in a prospective surveillance study of 67 patients over a 3-year period. Scans were evaluated and compared to findings of independent clinical evaluations. Sensitivity of gallium identification of tumor involving peripheral lymph nodes and soft tissues, abdomen, mediastinum, and osseous sites was 68% to 100%; overall sensitivity of this technique is 82% with specificity of 99% in 570 organ system assessments. Analysis of discordant findings when a site was clinically occult but gallium-positive showed gallium uptake to be true-positive in six of seven lymphatic sites, three of three lung and mediastinal sites, six of six abdominal sites, but in no brain or bone sites. Gallium lesions identified by computed tomographic scans proved to be false-positive at one lymphatic and one bone site, and false-negative at four otherwise clinically evident lymph node and soft tissue sites, seven pulmonary sites, and four brain sites. Gallium tomographic scanning provides a composite assessment of melanoma and may eliminate the need for other studies.

  11. Computer-Based Linguistic Analysis.

    ERIC Educational Resources Information Center

    Wright, James R.

    Noam Chomsky's transformational-generative grammar model may effectively be translated into an equivalent computer model. Phrase-structure rules and transformations are tested as to their validity and ordering by the computer via the process of random lexical substitution. Errors appearing in the grammar are detected and rectified, and formal…

  12. Bimolecular dynamics by computer analysis

    SciTech Connect

    Eilbeck, J.C.; Lomdahl, P.S.; Scott, A.C.

    1984-01-01

    As numerical tools (computers and display equipment) become more powerful and the atomic structures of important biological molecules become known, the importance of detailed computation of nonequilibrium biomolecular dynamics increases. In this manuscript we report results from a well developed study of the hydrogen bonded polypeptide crystal acetanilide, a model protein. Directions for future research are suggested. 9 references, 6 figures.

  13. In Vivo Quantitative Microcomputed Tomographic Analysis of Vasculature and Organs in a Normal and Diseased Mouse Model

    PubMed Central

    Das, Nanditha Mohan; Hatsell, Sarah; Nannuru, Kalyan; Huang, Lily; Wen, Xialing; Wang, Lili; Wang, Li-Hsien; Idone, Vincent; Meganck, Jeffrey A.; Murphy, Andrew; Economides, Aris; Xie, LiQin

    2016-01-01

    Non-bone in vivo micro-CT imaging has many potential applications for preclinical evaluation. Specifically, the in vivo quantification of changes in the vascular network and organ morphology in small animals, associated with the emergence and progression of diseases like bone fracture, inflammation and cancer, would be critical to the development and evaluation of new therapies for the same. However, there are few published papers describing the in vivo vascular imaging in small animals, due to technical challenges, such as low image quality and low vessel contrast in surrounding tissues. These studies have primarily focused on lung, cardiovascular and brain imaging. In vivo vascular imaging of mouse hind limbs has not been reported. We have developed an in vivo CT imaging technique to visualize and quantify vasculature and organ structure in disease models, with the goal of improved quality images. With 1–2 minutes scanning by a high speed in vivo micro-CT scanner (Quantum CT), and injection of a highly efficient contrast agent (Exitron nano 12000), vasculature and organ structure were semi-automatically segmented and quantified via image analysis software (Analyze). Vessels of the head and hind limbs, and organs like the heart, liver, kidneys and spleen were visualized and segmented from density maps. In a mouse model of bone metastasis, neoangiogenesis was observed, and associated changes to vessel morphology were computed, along with associated enlargement of the spleen. The in vivo CT image quality, voxel size down to 20 μm, is sufficient to visualize and quantify mouse vascular morphology. With this technique, in vivo vascular monitoring becomes feasible for the preclinical evaluation of small animal disease models. PMID:26910759

  14. In Vivo Quantitative Microcomputed Tomographic Analysis of Vasculature and Organs in a Normal and Diseased Mouse Model.

    PubMed

    Das, Nanditha Mohan; Hatsell, Sarah; Nannuru, Kalyan; Huang, Lily; Wen, Xialing; Wang, Lili; Wang, Li-Hsien; Idone, Vincent; Meganck, Jeffrey A; Murphy, Andrew; Economides, Aris; Xie, LiQin

    2016-01-01

    Non-bone in vivo micro-CT imaging has many potential applications for preclinical evaluation. Specifically, the in vivo quantification of changes in the vascular network and organ morphology in small animals, associated with the emergence and progression of diseases like bone fracture, inflammation and cancer, would be critical to the development and evaluation of new therapies for the same. However, there are few published papers describing the in vivo vascular imaging in small animals, due to technical challenges, such as low image quality and low vessel contrast in surrounding tissues. These studies have primarily focused on lung, cardiovascular and brain imaging. In vivo vascular imaging of mouse hind limbs has not been reported. We have developed an in vivo CT imaging technique to visualize and quantify vasculature and organ structure in disease models, with the goal of improved quality images. With 1-2 minutes scanning by a high speed in vivo micro-CT scanner (Quantum CT), and injection of a highly efficient contrast agent (Exitron nano 12000), vasculature and organ structure were semi-automatically segmented and quantified via image analysis software (Analyze). Vessels of the head and hind limbs, and organs like the heart, liver, kidneys and spleen were visualized and segmented from density maps. In a mouse model of bone metastasis, neoangiogenesis was observed, and associated changes to vessel morphology were computed, along with associated enlargement of the spleen. The in vivo CT image quality, voxel size down to 20 μm, is sufficient to visualize and quantify mouse vascular morphology. With this technique, in vivo vascular monitoring becomes feasible for the preclinical evaluation of small animal disease models. PMID:26910759

  15. Hydrodynamic and dispersion behavior in a non-porous silica monolith through fluid dynamic study of a computational mimic reconstructed from sub-micro-tomographic scans.

    PubMed

    Loh, Kai-Chee; Vasudevan, Vivek

    2013-01-25

    An analysis of the transport properties of the bulk homogeneous core of a commercially available silica monolith (Chromolith(®)) is presented via direct numerical simulations in a topological model reconstructed from 3D nanotomographic scans at isotropic resolutions of 390 nm, 290 nm and 190 nm. The pore and skeleton size distributions were calculated from image analysis and a representative unit cell from each resolution was reconstructed to simulate the hydrodynamic transport properties using Computational Fluid Dynamics (CFD). A 30 μm × 30 μm × 30 μm unit cell extracted at 190 nm resolution was found to be representative of hydrodynamic permeability. Numerical peak parking simulations yielded an axial external obstruction factor (γ(e)) of 0.8. Mass transfer characteristics of a large non-penetrating molecule (BSA) were evaluated under non-retained conditions so as to elucidate the eddy dispersion contribution to total HETP. Transverse and axial dispersion length scales in the reconstructed model were resolved and related to the structural heterogeneities in the silica monolith. Deviations of simulated HETP from experimental measurements were attributed to a transcolumn dispersion contribution, which amounted to about 90% of the total HETP. The presented approach provides great scope to analyze the contributions of pore network topology to separation performance of silica monoliths (and other porous media) in HPLC applications. A significant reduction in simulation time and memory resources has been observed due to the lower scanning resolution, without significant loss in prediction accuracy. PMID:23290336

  16. Computational methods for global/local analysis

    NASA Technical Reports Server (NTRS)

    Ransom, Jonathan B.; Mccleary, Susan L.; Aminpour, Mohammad A.; Knight, Norman F., Jr.

    1992-01-01

    Computational methods for global/local analysis of structures which include both uncoupled and coupled methods are described. In addition, global/local analysis methodology for automatic refinement of incompatible global and local finite element models is developed. Representative structural analysis problems are presented to demonstrate the global/local analysis methods.

  17. Scanning Tomographic Acoustic Microscopy

    NASA Astrophysics Data System (ADS)

    Wade, G.; Meyyappan, A.

    1988-07-01

    The technology for "seeing" with sound has an important and interesting history. Some of nature's creatures have been using sound waves for many millenia to image otherwise unobservable objects. The human species, lacking this natural ability, have overcome this deficiency by developing several different ultrasonic imaging techniques. acoustic microscopy is one such technique, which produces high resolution images of detailed structure of small objects in a non-destructive fashion. Two types of acoustic microscopes have evolved for industrial exploitation. They are the scanning laser acoustic microscope (SLAM) and the scanning acoustic microscope (SAM). In this paper, we review the principles of SLAM and describe how we use elements of SLAM to realize the scanning tomographic acoustic microscope (STAM). We describe the data acquisition process and the image reconstruction procedure. We also describe techniques to obtain projection data from different angles of wave incidence enabling us to reconstruct different planes of a complex specimen tomo-graphically. Our experimental results show that STAM is capable of producing high-quality high-resolution subsurface images.

  18. Dynamic three-dimensional echocardiographic imaging of congenital heart defects in infants and children by computer-controlled tomographic parallel slicing using a single integrated ultrasound instrument.

    PubMed

    Fulton, D R; Marx, G R; Pandian, N G; Romero, B A; Mumm, B; Krauss, M; Wollschläger, H; Ludomirsky, A; Cao, Q L

    1994-03-01

    Three-dimensional cardiac reconstruction generated from transesophageal interrogation can be performed using an integrated unit that captures, processes, and postprocesses tomographic parallel slices of the heart. This probe was used for infants and young children in the transthoracic position to evaluate the feasibility of producing three-dimensional cardiac images with capability for real-time dynamic display. Twenty-two infants and children (range 1 day-3.5 years) underwent image acquisition using a 16 mm 5 MHz 64 element probe placed over the precordium. Two infants were also imaged from the subcostal position. Data was obtained and stored over a single cardiac cycle after acceptable cardiac and respiratory gating intervals were met. The transducer was advanced in 0.5-1 mm increments over the cardiac structures using identical acquisition criteria. The images were reconstructed from the stored digital cubic format and could be oriented in any desired plane. In 9 of the 22 infants the images obtained were of optimal quality. The images obtained displayed normal cardiac structures emphasizing depth relationships as well as visualization of planes not generally demonstrated by two-dimensional imaging. Several lesions were also depicted in a unique fashion using this technique. Though the method employed was limited by movement artifact and reconstruction time, the quality of the three-dimensional display was excellent and enhanced by real-time demonstration. The transthoracic approach was successful in capturing sufficient data to create three-dimensional images, which may have further application in more accurate diagnosis of complex cardiac abnormalities and generation of planes of view which could duplicate surgical visualization of a lesion. Further assessment of the technique in infants with congenital heart disease is warranted. PMID:10146717

  19. Computer applications for engineering/structural analysis

    NASA Astrophysics Data System (ADS)

    Zaslawsky, M.; Samaddar, S. K.

    1991-10-01

    Analysts and organizations have a tendency to lock themselves into specific codes with the obvious consequence of not addressing the real problem and thus reaching the wrong conclusion. This paper discusses the role of the analyst in selecting computer codes. The participation and support of a computation division in modifying the source program, configuration management, and pre- and post-processing of codes are among the subjects discussed. Specific examples illustrating the computer code selection process are described in the following problem areas: soil structure interaction, structural analysis of nuclear reactors, analysis of waste tanks where fluid structure interaction is important, analysis of equipment, structure-structure interaction, analysis of the operation of the superconductor supercollider which includes friction and transient temperature, and 3D analysis of the 10-meter telescope being built in Hawaii. Validation and verification of computer codes and their impact on the selection process are also discussed.

  20. Computer applications for engineering/structural analysis

    SciTech Connect

    Zaslawsky, M.; Samaddar, S.K.

    1991-01-01

    Analysts and organizations have a tendency to lock themselves into specific codes with the obvious consequences of not addressing the real problem and thus reaching the wrong conclusion. This paper discusses the role of the analyst in selecting computer codes. The participation and support of a computation division in modifying the source program, configuration management, and pre- and post-processing of codes are among the subjects discussed. Specific examples illustrating the computer code selection process are described in the following problem areas: soil structure interaction, structural analysis of nuclear reactors, analysis of waste tanks where fluid structure interaction is important, analysis of equipment, structure-structure interaction, analysis of the operation of the superconductor supercollider which includes friction and transient temperature, and 3D analysis of the 10-meter telescope being built in Hawaii. Validation and verification of computer codes and their impact on the selection process are also discussed.

  1. Producing a full-scale model from computed tomographic data with the rapid prototyping technique using the binder jet method: a comparison with the laser lithography method using a dry skull.

    PubMed

    Ono, I; Abe, K; Shiotani, S; Hirayama, Y

    2000-11-01

    Rapid prototyping using the binder jet method has recently been established and has already produced excellent results in industrial applications. The authors recently developed a technique for producing a full-scale model from computed tomographic (CT) data with the binder jet method as an approach to overcome the shortcomings of the laser lithography method, which is already widely used in medicine. They conducted a comparative investigation of full-scale models made with both techniques using a dry skull to determine the accuracy of the models. It was clearly demonstrated that the accuracy of the binder jet method was high enough to be used in craniomaxillofacial surgery because it was the same as the laser lithography method. This study employed data from the latest helical volume scan computed tomography device using a multidetector. The study showed that the new rapid prototyping technique was satisfactory in terms of speed, cost, installation environment, and accuracy of models, and that detailed shapes and structures can be reproduced well. Because this technique has many advantages over the laser lithography method, it should play a major role in craniomaxillofacial surgery and in other medical fields in combination with advances in CT devices. Although plaster is a more suitable fixation material when the emphasis is on the reproducibility of detailed structures, the binder jet method using starch is extremely useful for simulating operations and determining implant shapes because it allows for the prompt production of models. PMID:11314492

  2. IUE Data Analysis Software for Personal Computers

    NASA Technical Reports Server (NTRS)

    Thompson, R.; Caplinger, J.; Taylor, L.; Lawton , P.

    1996-01-01

    This report summarizes the work performed for the program titled, "IUE Data Analysis Software for Personal Computers" awarded under Astrophysics Data Program NRA 92-OSSA-15. The work performed was completed over a 2-year period starting in April 1994. As a result of the project, 450 IDL routines and eight database tables are now available for distribution for Power Macintosh computers and Personal Computers running Windows 3.1.

  3. Performance of analytical methods for tomographic gamma scanning

    SciTech Connect

    Prettyman, T.H.; Mercer, D.J.

    1997-06-01

    The use of gamma-ray computerized tomography for nondestructive assay of radioactive materials has led to the development of specialized analytical methods. Over the past few years, Los Alamos has developed and implemented a computer code, called ARC-TGS, for the analysis of data obtained by tomographic gamma scanning (TGS). ARC-TGS reduces TGS transmission and emission tomographic data, providing the user with images of the sample contents, the activity or mass of selected radionuclides, and an estimate of the uncertainty in the measured quantities. The results provided by ARC-TGS can be corrected for self-attenuation when the isotope of interest emits more than one gamma-ray. In addition, ARC-TGS provides information needed to estimate TGS quantification limits and to estimate the scan time needed to screen for small amounts of radioactivity. In this report, an overview of the analytical methods used by ARC-TGS is presented along with an assessment of the performance of these methods for TGS.

  4. Computer Programming in a Spatial Analysis Course.

    ERIC Educational Resources Information Center

    Gesler, Wilbert; Kaplan, Abram

    1993-01-01

    Contends that students in spatial analysis courses generally are familiar with computer use and programs but lack basic computer programing skills. Describes four exercises in which students learn programing using BASIC and dBASE. Asserts that programming exercises help students clarify concepts, understand the rationale behind calculations, use…

  5. Discourse Analysis of Teaching Computing Online

    ERIC Educational Resources Information Center

    Bower, Matt

    2009-01-01

    This paper analyses the teaching and learning of computing in a Web-conferencing environment. A discourse analysis of three introductory programming learning episodes is presented to demonstrate issues and effects that arise when teaching computing using such an approach. The subject of discussion, the interactive nature of discussion and any…

  6. A Computer Language for ECG Contour Analysis

    PubMed Central

    McConnochie, John W.

    1982-01-01

    The purpose of this paper is to demonstrate contructively that criteria for ECG contour analysis can be interpreted directly by a computer. Thereby, the programming task is greatly reduced. Direct interpretation is achieved by the creation of a computer language that is well-suited for the expression of such criteria. Further development of the language is planned.

  7. Computer aided analysis of phonocardiogram.

    PubMed

    Singh, J; Anand, R S

    2007-01-01

    In the present paper analysis of phonocardiogram (PCG) records are presented. The analysis has been carried out in both time and frequency domains with the aim of detecting certain correlations between the time and frequency domain representations of PCG. The analysis is limited to first and second heart sounds (S1 and S2) only. In the time domain analysis the moving window averaging technique is used to determine the occurrence of S1 and S2, which helps in determination of cardiac interval and absolute and relative time duration of individual S1 and S2, as well as absolute and relative duration between them. In the frequency domain, fast Fourier transform (FFT) of the complete PCG record, and short time Fourier transform (STFT) and wavelet transform of individual heart sounds have been carried out. The frequency domain analysis gives an idea about the dominant frequency components in individual records and frequency spectrum of individual heart sounds. A comparative observation on both the analyses gives some correlation between time domain and frequency domain representations of PCG. PMID:17701776

  8. Radiological Safety Analysis Computer Program

    Energy Science and Technology Software Center (ESTSC)

    2001-08-28

    RSAC-6 is the latest version of the RSAC program. It calculates the consequences of a release of radionuclides to the atmosphere. Using a personal computer, a user can generate a fission product inventory; decay and in-grow the inventory during transport through processes, facilities, and the environment; model the downwind dispersion of the activity; and calculate doses to downwind individuals. Internal dose from the inhalation and ingestion pathways is calculated. External dose from ground surface andmore » plume gamma pathways is calculated. New and exciting updates to the program include the ability to evaluate a release to an enclosed room, resuspension of deposited activity and evaluation of a release up to 1 meter from the release point. Enhanced tools are included for dry deposition, building wake, occupancy factors, respirable fraction, AMAD adjustment, updated and enhanced radionuclide inventory and inclusion of the dose-conversion factors from FOR 11 and 12.« less

  9. Distributed computing and nuclear reactor analysis

    SciTech Connect

    Brown, F.B.; Derstine, K.L.; Blomquist, R.N.

    1994-03-01

    Large-scale scientific and engineering calculations for nuclear reactor analysis can now be carried out effectively in a distributed computing environment, at costs far lower than for traditional mainframes. The distributed computing environment must include support for traditional system services, such as a queuing system for batch work, reliable filesystem backups, and parallel processing capabilities for large jobs. All ANL computer codes for reactor analysis have been adapted successfully to a distributed system based on workstations and X-terminals. Distributed parallel processing has been demonstrated to be effective for long-running Monte Carlo calculations.

  10. Computer aided cogeneration feasibility analysis

    SciTech Connect

    Anaya, D.A.; Caltenco, E.J.L.; Robles, L.F.

    1996-12-31

    A successful cogeneration system design depends of several factors, and the optimal configuration can be founded using a steam and power simulation software. The key characteristics of one of this kind of software are described below, and its application on a process plant cogeneration feasibility analysis is shown in this paper. Finally a study case is illustrated. 4 refs., 2 figs.

  11. Economic Analysis. Computer Simulation Models.

    ERIC Educational Resources Information Center

    Sterling Inst., Washington, DC. Educational Technology Center.

    A multimedia course in economic analysis was developed and used in conjunction with the United States Naval Academy. (See ED 043 790 and ED 043 791 for final reports of the project evaluation and development model.) This volume of the text discusses the simulation of behavioral relationships among variable elements in an economy and presents…

  12. When Planning Screw Fracture Fixation Why the 5.5 mm Screw is the Goldilocks Screw. An Observational Computer Tomographic Study of Fifth Metatarsal Bone Anatomy in a Sample of Patients

    PubMed Central

    Iselin, Lukas D.; Ramawat, Sunil; Hanratty, Brian; Klammer, Georg; Stavrou, Peter

    2015-01-01

    Abstract We wanted to verify our clinical experience that the 5.5 mm screw was ideal in the majority of fifth metatarsal fracture fixation. The size of a screw is important for the successful surgical treatment of these fractures in order to obtain the maximal stability while reducing the risk for iatrogenic fracture. A sample of patients undergoing computer tomographic imaging of the foot for investigation other than fifth metatarsal pathology were recruited. The parameters of the fifth metatarsal bone anatomy were measured. These parameters of the 5.5 mm screw were correlated with this data. The upper parameter (the diameter of the threads) was 5.5 and the lower parameter (the diameter of the shank) was 4.0 mm. Twenty seven patients were recruited. The proximal third internal diameter ranged from 3.6 to 7.0 mm with a mean of 5.0 mm. 93% of the metatarsals could easily accommodate the 5.5 mm screw. Two of the metatarsals had an internal diameter of < 4 mm (7%). It is our belief that the 5.5 mm screw may be used safely in the majority of patients with fifth metatarsal fractures. PMID:25950685

  13. Statistical energy analysis computer program, user's guide

    NASA Technical Reports Server (NTRS)

    Trudell, R. W.; Yano, L. I.

    1981-01-01

    A high frequency random vibration analysis, (statistical energy analysis (SEA) method) is examined. The SEA method accomplishes high frequency prediction of arbitrary structural configurations. A general SEA computer program is described. A summary of SEA theory, example problems of SEA program application, and complete program listing are presented.

  14. Use of Some "Discriminant Analysis" Computer Programs

    ERIC Educational Resources Information Center

    Huberty, Carl J.

    1977-01-01

    The objective of this paper is to review the outputs of selected computer programs often used to carry out a "discriminant analysis" with respect to two purposes of such an analysis, discrimination and classification. The programs selected are three BMD programs. (Author/JKS)

  15. A computational image analysis glossary for biologists.

    PubMed

    Roeder, Adrienne H K; Cunha, Alexandre; Burl, Michael C; Meyerowitz, Elliot M

    2012-09-01

    Recent advances in biological imaging have resulted in an explosion in the quality and quantity of images obtained in a digital format. Developmental biologists are increasingly acquiring beautiful and complex images, thus creating vast image datasets. In the past, patterns in image data have been detected by the human eye. Larger datasets, however, necessitate high-throughput objective analysis tools to computationally extract quantitative information from the images. These tools have been developed in collaborations between biologists, computer scientists, mathematicians and physicists. In this Primer we present a glossary of image analysis terms to aid biologists and briefly discuss the importance of robust image analysis in developmental studies. PMID:22872081

  16. Automating sensitivity analysis of computer models using computer calculus

    SciTech Connect

    Oblow, E.M.; Pin, F.G.

    1985-01-01

    An automated procedure for performing sensitivity analyses has been developed. The procedure uses a new FORTRAN compiler with computer calculus capabilities to generate the derivatives needed to set up sensitivity equations. The new compiler is called GRESS - Gradient Enhanced Software System. Application of the automated procedure with ''direct'' and ''adjoint'' sensitivity theory for the analysis of non-linear, iterative systems of equations is discussed. Calculational efficiency consideration and techniques for adjoint sensitivity analysis are emphasized. The new approach is found to preserve the traditional advantages of adjoint theory while removing the tedious human effort previously needed to apply this theoretical methodology. Conclusions are drawn about the applicability of the automated procedure in numerical analysis and large-scale modelling sensitivity studies. 24 refs., 2 figs.

  17. A field proof-of-concept of tomographic slug tests in an anisotropic littoral aquifer

    NASA Astrophysics Data System (ADS)

    Paradis, Daniel; Gloaguen, Erwan; Lefebvre, René; Giroux, Bernard

    2016-05-01

    Hydraulic tomography is increasingly recognized as a characterization approach that can image pathways or barriers to flow as well as their connectivity. In this study, we assess the performance of a transient analysis of tomographic slug test head data in estimating heterogeneity in horizontal hydraulic conductivity (Kh), hydraulic conductivity anisotropy (the ratio between vertical and horizontal hydraulic conductivity - Kv/Kh) and specific storage (Ss) under actual field conditions. The tomographic experiment was carried out between two wells in a moderately heterogeneous and highly anisotropic silt and sand littoral aquifer. In this field proof-of-concept, the inversion of the two-dimensional (2D) head dataset was computed with a 2D radial flow algorithm that considers Kh, Kv/Kh, Ss and wellbore storage effects. This study demonstrated that a transient analysis of tomographic slug tests is able to capture the key features of the littoral environment of the test: the vertical profiles of Kh and Kv are indeed in agreement with those from other field and laboratory tests, and Ss values exhibit physically plausible profiles. Furthermore, the simulation of independent inter-well hydraulic tests (slug and pumping tests screened over the entire aquifer) using resolved Kh, Kv/Kh and Ss tomograms produce responses very close to field observations. This study demonstrates that the effects of fine scale heterogeneity that induces K-anisotropy at larger scales can be captured through a transient analysis of tomographic slug tests, which are very difficult to quantify otherwise with conventional hydraulic tests, thus allowing a better representation of properties controlling flow and transport in aquifer systems.

  18. Gynecologic electrical impedance tomograph

    NASA Astrophysics Data System (ADS)

    Korjenevsky, A.; Cherepenin, V.; Trokhanova, O.; Tuykin, T.

    2010-04-01

    Electrical impedance tomography extends to the new and new areas of the medical diagnostics: lungs, breast, prostate, etc. The feedback from the doctors who use our breast EIT diagnostic system has induced us to develop the 3D electrical impedance imaging device for diagnostics of the cervix of the uterus - gynecologic impedance tomograph (GIT). The device uses the same measuring approach as the breast imaging system: 2D flat array of the electrodes arranged on the probe with handle is placed against the body. Each of the 32 electrodes of the array is connected in turn to the current source while the rest electrodes acquire the potentials on the surface. The current flows through the electrode of the array and returns through the remote electrode placed on the patient's limb. The voltages are measured relative to another remote electrode. The 3D backprojection along equipotential surfaces is used to reconstruct conductivity distribution up to approximately 1 cm in depth. Small number of electrodes enables us to implement real time imaging with a few frames per sec. rate. The device is under initial testing and evaluation of the imaging capabilities and suitability of usage.

  19. Computer aided nonlinear electrical networks analysis

    NASA Technical Reports Server (NTRS)

    Slapnicar, P.

    1977-01-01

    Techniques used in simulating an electrical circuit with nonlinear elements for use in computer-aided circuit analysis programs are described. Elements of the circuit include capacitors, resistors, inductors, transistors, diodes, and voltage and current sources (constant or time varying). Simulation features are discussed for dc, ac, and/or transient circuit analysis. Calculations are based on the model approach of formulating the circuit equations. A particular solution of transient analysis for nonlinear storage elements is described.

  20. Structural analysis of the human tibia in men with spinal cord injury by tomographic (pQCT) serial scans.

    PubMed

    Rittweger, Jörn; Goosey-Tolfrey, Vicky L; Cointry, Gustavo; Ferretti, José Luis

    2010-09-01

    Spinal cord injury (SCI), as a primarily neurological disorder that causes muscular atrophy, is well known to be associated with sub-lesional bone losses. These losses are more pronounced from epiphyseal than from diaphyseal regions. We hypothesized that this discrepancy may be explained by anatomical variation in endocortical circumference. Nine men who had attracted SCI 9 to 32 (mean 21.4) years prior to study inclusion were matched to able bodied control (Ctrl) people by age, height and weight. Serial scans by peripheral quantitative computed tomography were obtained from the tibia at steps corresponding to 5%-steps of the tibias length (s05 to s95, from distal to the proximal end of the tibia). As expected, SCI people had lower total bone mineral content (vBMC.tot) than able bodied control people (P<0.001 at all sites). This group difference (DeltavBMC.tot) was more pronounced at the distal and proximal tibia than in the shaft (P<0.001), and it amounted to 51% at s05, to 22% at s40, and to 47% at s95. Both endocortical and periosteal circumference were better predictors of DeltavBMC.tot (R(2)=0.98 and R(2)=0.97, respectively; P<0.001 in both cases) than vBMC.tot (R(2)=0.58, P<0.001), suggesting that anatomical variation in geometry, rather than in bone mass can explain differential rates of bone loss after SCI. Moreover, the s04:s38 ratio in vBMC.tot was found to be 1.00 (95% confidence interval: 0.95-1.05) in the Ctrl group, and 0.63 in the SCI group (P<0.001, 95% confidence interval: 0.54-0.68). These findings offer a rationale to account for the discrepancy between epiphyseal and diaphyseal bone losses following SCI. The suggestion is that the bone adaptive responses involved are limited in time, and that the reduced surface:volume ratio constitutes a limit within the available time window, in particular in the diaphysis. Finally, the drastically reduced s04:s38 vBMC.tot ratio observed in the SCI group in this study provides a rationale to scrutinize this

  1. Computer aided stress analysis of long bones utilizing computer tomography

    SciTech Connect

    Marom, S.A.

    1986-01-01

    A computer aided analysis method, utilizing computed tomography (CT) has been developed, which together with a finite element program determines the stress-displacement pattern in a long bone section. The CT data file provides the geometry, the density and the material properties for the generated finite element model. A three-dimensional finite element model of a tibial shaft is automatically generated from the CT file by a pre-processing procedure for a finite element program. The developed pre-processor includes an edge detection algorithm which determines the boundaries of the reconstructed cross-sectional images of the scanned bone. A mesh generation procedure than automatically generates a three-dimensional mesh of a user-selected refinement. The elastic properties needed for the stress analysis are individually determined for each model element using the radiographic density (CT number) of each pixel with the elemental borders. The elastic modulus is determined from the CT radiographic density by using an empirical relationship from the literature. The generated finite element model, together with applied loads, determined from existing gait analysis and initial displacements, comprise a formatted input for the SAP IV finite element program. The output of this program, stresses and displacements at the model elements and nodes, are sorted and displayed by a developed post-processor to provide maximum and minimum values at selected locations in the model.

  2. Computer analysis of foetal monitoring signals.

    PubMed

    Nunes, Inês; Ayres-de-Campos, Diogo

    2016-01-01

    Five systems for computer analysis of foetal monitoring signals are currently available, incorporating the evaluation of cardiotocographic (CTG) or combined CTG with electrocardiographic ST data. All systems have been integrated with central monitoring stations, allowing the simultaneous monitoring of several tracings on the same computer screen in multiple hospital locations. Computer analysis elicits real-time visual and sound alerts for health care professionals when abnormal patterns are detected, with the aim of prompting a re-evaluation and subsequent clinical action, if considered necessary. Comparison between the CTG analyses provided by the computer and clinical experts has been carried out in all systems, and in three of them, the accuracy of computer alerts in predicting newborn outcomes was evaluated. Comparisons between these studies are hampered by the differences in selection criteria and outcomes. Two of these systems have just completed multicentre randomised clinical trials comparing them with conventional CTG monitoring, and their results are awaited shortly. For the time being, there is limited evidence regarding the impact of computer analysis of foetal monitoring signals on perinatal indicators and on health care professionals' behaviour. PMID:26211832

  3. ASTEC: Controls analysis for personal computers

    NASA Technical Reports Server (NTRS)

    Downing, John P.; Bauer, Frank H.; Thorpe, Christopher J.

    1989-01-01

    The ASTEC (Analysis and Simulation Tools for Engineering Controls) software is under development at Goddard Space Flight Center (GSFC). The design goal is to provide a wide selection of controls analysis tools at the personal computer level, as well as the capability to upload compute-intensive jobs to a mainframe or supercomputer. The project is a follow-on to the INCA (INteractive Controls Analysis) program that has been developed at GSFC over the past five years. While ASTEC makes use of the algorithms and expertise developed for the INCA program, the user interface was redesigned to take advantage of the capabilities of the personal computer. The design philosophy and the current capabilities of the ASTEC software are described.

  4. Discrete computer analysis in petroleum geology

    SciTech Connect

    Zakharian, A.Z.

    1995-08-01

    Computer analysis must not be resembling on geologist`s work, having its own way because of uncertainty and shortness of geological information even on mature stage of exploration, when our original system of formal discrete computer analysis, realised on {open_quotes}FoxPro for Windows{close_quotes} with not substantial but probabilistic (without ever driving the usual maps) representation of geological situation was used for picking out the sets of best points for exploration drilling in south part of Dheprovsko-Donetzky oil-gas basin.

  5. Temporal fringe pattern analysis with parallel computing

    SciTech Connect

    Tuck Wah Ng; Kar Tien Ang; Argentini, Gianluca

    2005-11-20

    Temporal fringe pattern analysis is invaluable in transient phenomena studies but necessitates long processing times. Here we describe a parallel computing strategy based on the single-program multiple-data model and hyperthreading processor technology to reduce the execution time. In a two-node cluster workstation configuration we found that execution periods were reduced by 1.6 times when four virtual processors were used. To allow even lower execution times with an increasing number of processors, the time allocated for data transfer, data read, and waiting should be minimized. Parallel computing is found here to present a feasible approach to reduce execution times in temporal fringe pattern analysis.

  6. Interfacing Computer Aided Parallelization and Performance Analysis

    NASA Technical Reports Server (NTRS)

    Jost, Gabriele; Jin, Haoqiang; Labarta, Jesus; Gimenez, Judit; Biegel, Bryan A. (Technical Monitor)

    2003-01-01

    When porting sequential applications to parallel computer architectures, the program developer will typically go through several cycles of source code optimization and performance analysis. We have started a project to develop an environment where the user can jointly navigate through program structure and performance data information in order to make efficient optimization decisions. In a prototype implementation we have interfaced the CAPO computer aided parallelization tool with the Paraver performance analysis tool. We describe both tools and their interface and give an example for how the interface helps within the program development cycle of a benchmark code.

  7. Tomographic multiphase flow measurement.

    PubMed

    Sætre, C; Johansen, G A; Tjugum, S A

    2012-07-01

    Measurement of multiphase flow of gas, oil and water is not at all trivial and in spite of considerable achievements over the past two decades, important challenges remain (Corneliussen et al., 2005). These are related to reducing measurement uncertainties arising from variations in the flow regime, improving long term stability and developing new means for calibration, adjustment and verification of the multiphase flow meters. This work focuses on the first two issues using multi gamma beam (MGB) measurements for identification of the type of flow regime. Further gamma ray tomographic measurements are used for reference of the gas/liquid distribution. For the MGB method one Am-241 source with principal emission at 59.5 keV is used because this relatively low energy enables efficient collimation and thereby shaping of the beams, as well as compact detectors. One detector is placed diametrically opposite the source whereas the second is positioned to the side so that this beam is close to the pipe wall. The principle is then straight forward to compare the measured intensities of these detectors and through that identify the flow pattern, i.e. the instantaneous cross-sectional gas-liquid distribution. The measurement setup also includes Compton scattering measurements, which can provide information about the changes in the water salinity for flow segments with high water liquid ratio and low gas fractions. By measuring the transmitted intensity in short time slots (<100 ms), rapid regime variations are revealed. From this we can select the time sections suitable for salinity measurements. Since the salinity variations change at the time scale of hours, a running average can be performed to increase the accuracy of the measurements. Recent results of this work will be presented here. PMID:22341954

  8. X ray computed tomography for failure analysis

    NASA Astrophysics Data System (ADS)

    Bossi, Richard H.; Crews, Alan R.; Georgeson, Gary E.

    1992-08-01

    Under a preliminary testing task assignment of the Advanced Development of X-Ray Computed Tomography Application program, computed tomography (CT) has been studied for its potential as a tool to assist in failure analysis investigations. CT provides three-dimensional spatial distribution of material that can be used to assess internal configurations and material conditions nondestructively. This capability has been used in failure analysis studies to determine the position of internal components and their operation. CT is particularly advantageous on complex systems, composite failure studies, and testing under operational or environmental conditions. CT plays an important role in reducing the time and effort of a failure analysis investigation. Aircraft manufacturing or logistical facilities perform failure analysis operations routinely and could be expected to reduce schedules, reduce costs and/or improve evaluation on about 10 to 30 percent of the problems they investigate by using CT.

  9. Central odontogenic fibroma (simple type) in a four-year-old boy: atypical cone-beam computed tomographic appearance with periosteal reaction

    PubMed Central

    Anbiaee, Najme; Sanaei, Alireza

    2015-01-01

    Central odontogenic fibroma (COF) is a rare benign tumor that accounts for 0.1% of all odontogenic tumors. A case of COF (simple type) of the mandible in a four-year-old boy is described in this report. The patient showed asymptomatic swelling in the right inferior border of the lower jaw for one week. A panoramic radiograph showed a poorly-defined destructive unilocular radiolucent area. Cone-beam computed tomography showed expansion and perforation of the adjacent cortical bone plates. A periosteal reaction with the Codman triangle pattern was clearly visible in the buccal cortex. Since the tumor had destroyed a considerable amount of bone, surgical resection was performed. No recurrence was noted. PMID:26125006

  10. Computer based terrain analysis for operational planning

    SciTech Connect

    Powell, D.R.

    1987-01-01

    Analysis of operational capability is an ongoing task for military commanders. In peacetime, most analysis is conducted via computer based combat simulations, where selected force structures engage in simulated combat to gain insight into specific scenarios. The command and control (C/sup 2/) mechanisms that direct combat forces are often neglected relative to the fidelity of representation of mechanical and physical entities. C/sup 2/ capabilities should include the ability to plan a mission, monitor execution activities, and redirect combat power when appropriate. This paper discusses the development of a computer based approach to mission planning for land warfare. The aspect emphasized is the computation and representation of relevant terrain features in the context of operational planning.

  11. Final Report Computational Analysis of Dynamical Systems

    SciTech Connect

    Guckenheimer, John

    2012-05-08

    This is the final report for DOE Grant DE-FG02-93ER25164, initiated in 1993. This grant supported research of John Guckenheimer on computational analysis of dynamical systems. During that period, seventeen individuals received PhD degrees under the supervision of Guckenheimer and over fifty publications related to the grant were produced. This document contains copies of these publications.

  12. COMPUTER ANALYSIS OF PLANAR GAMMA CAMERA IMAGES

    EPA Science Inventory



    COMPUTER ANALYSIS OF PLANAR GAMMA CAMERA IMAGES

    T Martonen1 and J Schroeter2

    1Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, U.S. EPA, Research Triangle Park, NC 27711 USA and 2Curriculum in Toxicology, Unive...

  13. Computational analysis of a multistage axial compressor

    NASA Astrophysics Data System (ADS)

    Mamidoju, Chaithanya

    Turbomachines are used extensively in Aerospace, Power Generation, and Oil & Gas Industries. Efficiency of these machines is often an important factor and has led to the continuous effort to improve the design to achieve better efficiency. The axial flow compressor is a major component in a gas turbine with the turbine's overall performance depending strongly on compressor performance. Traditional analysis of axial compressors involves throughflow calculations, isolated blade passage analysis, Quasi-3D blade-to-blade analysis, single-stage (rotor-stator) analysis, and multi-stage analysis involving larger design cycles. In the current study, the detailed flow through a 15 stage axial compressor is analyzed using a 3-D Navier Stokes CFD solver in a parallel computing environment. Methodology is described for steady state (frozen rotor stator) analysis of one blade passage per component. Various effects such as mesh type and density, boundary conditions, tip clearance and numerical issues such as turbulence model choice, advection model choice, and parallel processing performance are analyzed. A high sensitivity of the predictions to the above was found. Physical explanation to the flow features observed in the computational study are given. The total pressure rise verses mass flow rate was computed.

  14. Renal Collecting System Anatomy in Living Kidney Donors by Computed Tomographic Urography: Protocol Accuracy Compared to Intravenous Pyelographic and Surgical Findings

    PubMed Central

    Tarzamni, Mohammad Kazem; Nezami, Nariman; Zomorrodi, Afshar; Fathi-Noroozlou, Samad; Piri, Reza; Naghavi-Behzad, Mohammad; Mojadidi, Mohammad Khalid; Bijan, Bijan

    2016-01-01

    Objectives: To evaluate the accuracy of triple-bolus computed tomography urography (CTU) as a surrogate of intravenous pyelography (IVP) for determining the anatomy of the urinary collecting system in living kidney donors. Materials and Methods: In an analytic descriptive cross-sectional study, 36 healthy kidney donors were recruited during 12 months. Preoperative IVP and CTU were utilized to evaluate kidneys’ anatomy; major and minor calyces and variation were used as anatomical indices to compare the accuracy of CTU and IVP; the images were then compared to surgical findings. Results: Thirty-six kidney donors (92% male; mean age: 28 ± 6 years) were enrolled in this study. The kappa coefficient value was significant and almost perfect for the CTU and IVP findings in detecting the pattern of calyces (kappa coefficient 0.92, asymptotic 95% confidence interval 0.86–0.97). Anatomic variations or anomalies of the urinary collecting system included the bifid pelvis (5.6%), duplication (8.3%), and extra-renal pelvis (2.8%). Both the sensitivity and specificity of CTU in the detection of the anatomy and variations were 100%; the sensitivity and specificity of IVP were 83.3% and 100%, respectively. Conclusions: The triple-bolus preoperative CTU can be considered an alternative to IVP for assessing the anatomy of the urinary collecting system. PMID:26958431

  15. Screw Placement and Osteoplasty Under Computed Tomographic-Fluoroscopic Guidance in a Case of Advanced Metastatic Destruction of the Iliosacral Joint

    SciTech Connect

    Trumm, Christoph Gregor; Rubenbauer, Bianca; Piltz, Stefan; Reiser, Maximilian F.; Hoffmann, Ralf-Thorsten

    2011-02-15

    We present a case of combined surgical screw placement and osteoplasty guided by computed tomography-fluoroscopy (CTF) in a 68-year-old man with unilateral osteolytic destruction and a pathological fracture of the iliosacral joint due to a metastasis from renal cell carcinoma. The patient experienced intractable lower back pain that was refractory to analgesia. After transarterial particle and coil embolization of the tumor-feeding vessels in the angiography unit, the procedure was performed under general anesthesia by an interdisciplinary team of interventional radiologists and trauma surgeons. Under intermittent single-shot CTF, two K wires were inserted into the left iliosacral joint from a lateral transiliac approach at the S1 level followed by two self-tapping surgical screws. Continuous CTF was used for monitoring of the subsequent polymethylmethacrylate injection through two vertebroplasty cannulas for further stabilization of the screw threads within the osteolytic sacral ala. Both the screw placement and cement injection were successful, with no complications occurring during or after the procedure. With additional nonsteroidal anti-inflammatory and opioid medication, the patient reported a marked decrease in his lower back pain and was able to move independently again at the 3-month follow-up assessment. In our patient with intolerable back pain due to tumor destruction and consequent pathological fracture of the iliosacral joint, CTF-guided iliosacral screw placement combined with osteoplasty was successful with respect to joint stabilization and a reduction in the need for analgesic therapy.

  16. Effect of age on bone mineral density and micro architecture in the radius and tibia of horses: An Xtreme computed tomographic study

    PubMed Central

    Fürst, A; Meier, D; Michel, S; Schmidlin, A; Held, L; Laib, A

    2008-01-01

    Background The effect of age on the bone mineral density and microarchitecture of the equine radius and tibia was investigated. Fifty-six bones from 15 horses aged four to 21 years were used. There were nine geldings and six mares, and none of the horses had any disease influencing bone properties. Xtreme computed tomography was used to evaluate a 9-mm segment of the diaphysis and metaphysis of each bone. The following variables were determined: length of the bone, circumference and diameter in the frontal and sagittal planes in the middle of the bone. Diaphysis: total volume, bone volume, bone volume ratio, slice area, bone area, marrow area, cortical and marrow thickness, bone mineral density, polar moment of inertia of the cortex. Metaphysis: total area, bone area, cortical bone area, cortical thickness, bone mineral density, bone mineral density in the cortex, bone mineral density in the trabecular region, trabecular number, trabecular thickness, trabecular separation, polar moment of inertia of the metaphysis, polar moment of inertia of the cortex of the metaphysis. Results Bone density and microarchitecture were not affected by breed or gender. However, the microarchitecture varied with the age of the horse; the number of trabeculae decreased significantly and the distance between trabeculae increased significantly with increasing age. There were no significant differences between bones of the left and right limbs or between the radius and tibia. Conclusion The variables investigated did not differ between geldings and mares. However, there were age-related changes in the microstructure of the bones. Further experimental studies are necessary to determine whether these changes reduce bone strength. Age-related changes in the bones were seen and may explain the higher incidence of fractures and fissures in older horses. PMID:18221526

  17. Three-dimensional micro-computed tomographic evaluation of periodontal regeneration: a human report of intrabony defects treated with Bio-Oss collagen.

    PubMed

    Nevins, Marc L; Camelo, Marcelo; Rebaudi, Alberto; Lynch, Samuel E; Nevins, Myron

    2005-08-01

    This study utilized three-dimensional micro-computed tomography (micro-CT) to evaluate the regenerative response to Bio-Oss Collagen when used alone or in combination with a Bio-Gide bilayer collagen membrane for the treatment of four intrabony defects (5 to 7 mm) around single-rooted teeth. The micro-CT observations are compared to the clinical, radiographic, and histologic results, which have been previously reported. After reflecting a full-thickness flap, thorough degranulation and root planing were accomplished. Bio-Oss Collagen was then used to fill the defects, and in two cases a Bio-Gide membrane was placed over the filled defect. Radiographs, clinical probing depths, and attachment levels were obtained before treatment and immediately preceding en bloc resection of teeth and surrounding tissues 9 months later. A mean pocket depth reduction of 5.75 mm and mean clinical attachment level gain of 5.25 mm were recorded. The histologic evaluation demonstrated the formation of a complete new attachment apparatus with new cementum, periodontal ligament, and alveolar bone at the level of and coronal to the calculus reference notch. Micro-CT evaluation confirmed the histologic results and demonstrated the absence of ankylosis or root resorption for all specimens. This human histologic study demonstrated that Bio-Oss Collagen has the capacity to facilitate regeneration of the periodontal attachment apparatus when placed in intrabony defects. Micro-CT observations confirmed the histologic results and enhanced the three-dimensional understanding of periodontal wound healing. The results indicate that micro-CT may be useful for three-dimensional evaluation of periodontal regenerative procedures. PMID:16089044

  18. Utilization of Cone-Beam Computed Tomographic Angiography in Planning for Gamma Knife Radiosurgery of Arteriovenous Malformations: A Case Series and Early Report

    PubMed Central

    Safain, Mina G.; Rahal, Jason P.; Raval, Ami; Rivard, Mark J.; Mignano, John; Wu, Julian; Malek, Adel M.

    2014-01-01

    Background The effectiveness of Gamma Knife radiosurgery (GKR) for cerebral arteriovenous malformations (AVM) is predicated on inclusion of the entire nidus while excluding normal tissue. As such, GKR may be limited by the resolution and accuracy of the imaging modality used in targeting. Objective We present the first case series to demonstrate the feasibility of utilizing ultra-high-resolution C-arm cone beam computed tomography angiography (CBCT-A) in AVM targeting. Methods From June 2009 to June 2013, CBCT-A was utilized for targeting of all patients with AVMs treated with GKR at our institution. Patients underwent Leksell stereotactic head frame placement followed by catheter-based biplane 2-D digital subtraction angiography (DSA), 3-D rotational angiography (3DRA), as well as CBCT-A. The CBCT-A dataset was used for stereotactic planning for GKR. Patients were followed up at 1, 3, 6, and 12 months, and then annually thereafter. Results CBCT-A-based targeting was used in twenty-two consecutive patients. CBCT-A provided detailed spatial resolution and sensitivity of nidal angioarchitecture enabling treatment. The average radiation dose to the margin of the AVM nidus corresponding to the 50% percent isodose line was 15.6 Gy. No patient had treatment-associated hemorrhage. At early follow-up (mean=16 months), 84% of patients had a decreasing or obliterated AVM nidus. Conclusion CBCT-A-guided radiosurgery is feasible and useful because it provides sufficient detailed resolution and sensitivity for imaging brain AVMs. PMID:24584136

  19. Risk analysis of computer system designs

    NASA Technical Reports Server (NTRS)

    Vallone, A.

    1981-01-01

    Adverse events during implementation can affect final capabilities, schedule and cost of a computer system even though the system was accurately designed and evaluated. Risk analysis enables the manager to forecast the impact of those events and to timely ask for design revisions or contingency plans before making any decision. This paper presents a structured procedure for an effective risk analysis. The procedure identifies the required activities, separates subjective assessments from objective evaluations, and defines a risk measure to determine the analysis results. The procedure is consistent with the system design evaluation and enables a meaningful comparison among alternative designs.

  20. Computer design and analysis of vacuum systems

    SciTech Connect

    Santeler, D.J.

    1987-07-01

    A computer program has been developed for an IBM compatible personal computer to assist in the design and analysis of vacuum systems. The program has a selection of 12 major schematics with several thousand minor variants incorporating diffusion, turbomolecular, cryogenic, ion, mechanical, and sorption pumps as well as circular tubes, bends, valves, traps, and purge gas connections. The gas throughput versus the inlet pressure of the pump is presented on a log--log graphical display. The conductance of each series component is sequentially added to the graph to obtain the net system behavior Q/sub (//sub P//sub )/. The component conductances may be calculated either from the inlet area and the transmission probability or from the tube length and the diameter. The gas-flow calculations are valid for orifices, short tubes, and long tubes throughout the entire pressure range from molecular through viscous to choked and nonchoked exit flows. The roughing-pump and high-vacuum-pump characteristic curves are numerically integrated to provide a graphical presentation of the system pumpdown. Outgassing data for different materials is then combined to produce a graph of the net system ''outgassing pressure.'' Computer routines are provided for differentiating a real pumpdown curve for system analysis. The computer program is included with the American Vacuum Society course, ''Advanced Vacuum System Design and Analysis,'' or it may be purchased from Process Applications, Inc.

  1. Correlation of Lung Collapse and Gas Exchange - A Computer Tomographic Study in Sheep and Pigs with Atelectasis in Otherwise Normal Lungs

    PubMed Central

    Hammermüller, Sören; Costa, Eduardo L. V.; Spieth, Peter M.; Hepp, Pierre; Carvalho, Alysson R.; Kraßler, Jens; Wrigge, Hermann; Amato, Marcelo B. P.; Reske, Andreas W.

    2015-01-01

    Background Atelectasis can provoke pulmonary and non-pulmonary complications after general anaesthesia. Unfortunately, there is no instrument to estimate atelectasis and prompt changes of mechanical ventilation during general anaesthesia. Although arterial partial pressure of oxygen (PaO2) and intrapulmonary shunt have both been suggested to correlate with atelectasis, studies yielded inconsistent results. Therefore, we investigated these correlations. Methods Shunt, PaO2 and atelectasis were measured in 11 sheep and 23 pigs with otherwise normal lungs. In pigs, contrasting measurements were available 12 hours after induction of acute respiratory distress syndrome (ARDS). Atelectasis was calculated by computed tomography relative to total lung mass (Mtotal). We logarithmically transformed PaO2 (lnPaO2) to linearize its relationships with shunt and atelectasis. Data are given as median (interquartile range). Results Mtotal was 768 (715–884) g in sheep and 543 (503–583) g in pigs. Atelectasis was 26 (16–47) % in sheep and 18 (13–23) % in pigs. PaO2 (FiO2 = 1.0) was 242 (106–414) mmHg in sheep and 480 (437–514) mmHg in pigs. Shunt was 39 (29–51) % in sheep and 15 (11–20) % in pigs. Atelectasis correlated closely with lnPaO2 (R2 = 0.78) and shunt (R2 = 0.79) in sheep (P-values<0.0001). The correlation of atelectasis with lnPaO2 (R2 = 0.63) and shunt (R2 = 0.34) was weaker in pigs, but R2 increased to 0.71 for lnPaO2 and 0.72 for shunt 12 hours after induction of ARDS. In both, sheep and pigs, changes in atelectasis correlated strongly with corresponding changes in lnPaO2 and shunt. Discussion and Conclusion In lung-healthy sheep, atelectasis correlates closely with lnPaO2 and shunt, when blood gases are measured during ventilation with pure oxygen. In lung-healthy pigs, these correlations were significantly weaker, likely because pigs have stronger hypoxic pulmonary vasoconstriction (HPV) than sheep and humans. Nevertheless, correlations improved also

  2. Expansion of the Multi-Link Frontier™ Coronary Bifurcation Stent: Micro-Computed Tomographic Assessment in Human Autopsy and Porcine Heart Samples

    PubMed Central

    Kralev, Stefan; Haag, Benjamin; Spannenberger, Jens; Lang, Siegfried; Brockmann, Marc A.; Bartling, Soenke; Marx, Alexander; Haase, Karl-Konstantin; Borggrefe, Martin; Süselbeck, Tim

    2011-01-01

    Background Treatment of coronary bifurcation lesions remains challenging, beyond the introduction of drug eluting stents. Dedicated stent systems are available to improve the technical approach to the treatment of these lesions. However dedicated stent systems have so far not reduced the incidence of stent restenosis. The aim of this study was to assess the expansion of the Multi-Link (ML) Frontier™ stent in human and porcine coronary arteries to provide the cardiologist with useful in-vitro information for stent implantation and selection. Methodology/Principal Findings Nine ML Frontier™ stents were implanted in seven human autopsy heart samples with known coronary artery disease and five ML Frontier™ stents were implanted in five porcine hearts. Proximal, distal and side branch diameters (PD, DD, SBD, respectively), corresponding opening areas (PA, DA, SBA) and the mean stent length (L) were assessed by micro-computed tomography (micro-CT). PD and PA were significantly smaller in human autopsy heart samples than in porcine heart samples (3.54±0.47 mm vs. 4.04±0.22 mm, p = 0.048; 10.00±2.42 mm2 vs. 12.84±1.38 mm2, p = 0.034, respectively) and than those given by the manufacturer (3.54±0.47 mm vs. 4.03 mm, p = 0.014). L was smaller in human autopsy heart samples than in porcine heart samples, although data did not reach significance (16.66±1.30 mm vs. 17.30±0.51 mm, p = 0.32), and significantly smaller than that given by the manufacturer (16.66±1.30 mm vs. 18 mm, p = 0.015). Conclusions/Significance Micro-CT is a feasible tool for exact surveying of dedicated stent systems and could make a contribution to the development of these devices. The proximal diameter and proximal area of the stent system were considerably smaller in human autopsy heart samples than in porcine heart samples and than those given by the manufacturer. Special consideration should be given to the stent deployment procedure (and to the follow-up) of dedicated

  3. A distributed multi-GPU system for high speed electron microscopic tomographic reconstruction.

    PubMed

    Zheng, Shawn Q; Branlund, Eric; Kesthelyi, Bettina; Braunfeld, Michael B; Cheng, Yifan; Sedat, John W; Agard, David A

    2011-07-01

    Full resolution electron microscopic tomographic (EMT) reconstruction of large-scale tilt series requires significant computing power. The desire to perform multiple cycles of iterative reconstruction and realignment dramatically increases the pressing need to improve reconstruction performance. This has motivated us to develop a distributed multi-GPU (graphics processing unit) system to provide the required computing power for rapid constrained, iterative reconstructions of very large three-dimensional (3D) volumes. The participating GPUs reconstruct segments of the volume in parallel, and subsequently, the segments are assembled to form the complete 3D volume. Owing to its power and versatility, the CUDA (NVIDIA, USA) platform was selected for GPU implementation of the EMT reconstruction. For a system containing 10 GPUs provided by 5 GTX295 cards, 10 cycles of SIRT reconstruction for a tomogram of 4096(2) × 512 voxels from an input tilt series containing 122 projection images of 4096(2) pixels (single precision float) takes a total of 1845 s of which 1032 s are for computation with the remainder being the system overhead. The same system takes only 39 s total to reconstruct 1024(2) × 256 voxels from 122 1024(2) pixel projections. While the system overhead is non-trivial, performance analysis indicates that adding extra GPUs to the system would lead to steadily enhanced overall performance. Therefore, this system can be easily expanded to generate superior computing power for very large tomographic reconstructions and especially to empower iterative cycles of reconstruction and realignment. PMID:21741915

  4. Computational strategies for tire monitoring and analysis

    NASA Technical Reports Server (NTRS)

    Danielson, Kent T.; Noor, Ahmed K.; Green, James S.

    1995-01-01

    Computational strategies are presented for the modeling and analysis of tires in contact with pavement. A procedure is introduced for simple and accurate determination of tire cross-sectional geometric characteristics from a digitally scanned image. Three new strategies for reducing the computational effort in the finite element solution of tire-pavement contact are also presented. These strategies take advantage of the observation that footprint loads do not usually stimulate a significant tire response away from the pavement contact region. The finite element strategies differ in their level of approximation and required amount of computer resources. The effectiveness of the strategies is demonstrated by numerical examples of frictionless and frictional contact of the space shuttle Orbiter nose-gear tire. Both an in-house research code and a commercial finite element code are used in the numerical studies.

  5. Computational analysis of forebody tangential slot blowing

    NASA Technical Reports Server (NTRS)

    Gee, Ken; Agosta-Greenman, Roxana M.; Rizk, Yehia M.; Schiff, Lewis B.; Cummings, Russell M.

    1994-01-01

    An overview of the computational effort to analyze forebody tangential slot blowing is presented. Tangential slot blowing generates side force and yawing moment which may be used to control an aircraft flying at high-angle-of-attack. Two different geometries are used in the analysis: (1) The High Alpha Research Vehicle; and (2) a generic chined forebody. Computations using the isolated F/A-18 forebody are obtained at full-scale wind tunnel test conditions for direct comparison with available experimental data. The effects of over- and under-blowing on force and moment production are analyzed. Time-accurate solutions using the isolated forebody are obtained to study the force onset timelag of tangential slot blowing. Computations using the generic chined forebody are obtained at experimental wind tunnel conditions, and the results compared with available experimental data. This computational analysis compliments the experimental results and provides a detailed understanding of the effects of tangential slot blowing on the flow field about simple and complex geometries.

  6. 3-dimensional strain fields from tomographic measurements

    NASA Astrophysics Data System (ADS)

    Haldrup, K.; Nielsen, S. F.; Mishnaevsky, L., Jr.; Beckmann, F.; Wert, J. A.

    2006-08-01

    Understanding the distributions of strain within solid bodies undergoing plastic deformations has been of interest for many years in a wide range of disciplines, ranging from basic materials science to biology. However, the desire to investigate these strain fields has been frustrated by the inaccessibility of the interior of most samples to detailed investigation without destroying the sample in the process. To some extent, this has been remedied by the development of advanced surface measurement techniques as well as computer models based on Finite Element methods. Over the last decade, this situation has changed by the introduction of a range of tomographic methods based both on advances in computer technology and in instrumentation, advances which have opened up the interior of optically opaque samples for detailed investigations. We present a general method for assessing the strain in the interior of marker-containing specimens undergoing various types of deformation. The results are compared with Finite Element modelling.

  7. Probabilistic structural analysis computer code (NESSUS)

    NASA Technical Reports Server (NTRS)

    Shiao, Michael C.

    1988-01-01

    Probabilistic structural analysis has been developed to analyze the effects of fluctuating loads, variable material properties, and uncertain analytical models especially for high performance structures such as SSME turbopump blades. The computer code NESSUS (Numerical Evaluation of Stochastic Structure Under Stress) was developed to serve as a primary computation tool for the characterization of the probabilistic structural response due to the stochastic environments by statistical description. The code consists of three major modules NESSUS/PRE, NESSUS/FEM, and NESSUS/FPI. NESSUS/PRE is a preprocessor which decomposes the spatially correlated random variables into a set of uncorrelated random variables using a modal analysis method. NESSUS/FEM is a finite element module which provides structural sensitivities to all the random variables considered. NESSUS/FPI is Fast Probability Integration method by which a cumulative distribution function or a probability density function is calculated.

  8. Statistical Data Analysis in the Computer Age

    NASA Astrophysics Data System (ADS)

    Efron, Bradley; Tibshirani, Robert

    1991-07-01

    Most of our familiar statistical methods, such as hypothesis testing, linear regression, analysis of variance, and maximum likelihood estimation, were designed to be implemented on mechanical calculators. modern electronic computation has encouraged a host of new statistical methods that require fewer distributional assumptions than their predecessors and can be applied to more complicated statistical estimators. These methods allow the scientist to explore and describe data and draw valid statistical inferences without the usual concerns for mathematical tractability. This is possible because traditional methods of mathematical analysis are replaced by specially constructed computer algorithms. Mathematics has not disappeared from statistical theory. It is the main method for deciding which algorithms are correct and efficient tools for automating statistical inference.

  9. Pulmonary vessel segmentation utilizing curved planar reformation and optimal path finding (CROP) in computed tomographic pulmonary angiography (CTPA) for CAD applications

    NASA Astrophysics Data System (ADS)

    Zhou, Chuan; Chan, Heang-Ping; Kuriakose, Jean W.; Chughtai, Aamer; Wei, Jun; Hadjiiski, Lubomir M.; Guo, Yanhui; Patel, Smita; Kazerooni, Ella A.

    2012-03-01

    Vessel segmentation is a fundamental step in an automated pulmonary embolism (PE) detection system. The purpose of this study is to improve the segmentation scheme for pulmonary vessels affected by PE and other lung diseases. We have developed a multiscale hierarchical vessel enhancement and segmentation (MHES) method for pulmonary vessel tree extraction based on the analysis of eigenvalues of Hessian matrices. However, it is difficult to segment the pulmonary vessels accurately under suboptimal conditions, such as vessels occluded by PEs, surrounded by lymphoid tissues or lung diseases, and crossing with other vessels. In this study, we developed a new vessel refinement method utilizing curved planar reformation (CPR) technique combined with optimal path finding method (MHES-CROP). The MHES segmented vessels straightened in the CPR volume was refined using adaptive gray level thresholding where the local threshold was obtained from least-square estimation of a spline curve fitted to the gray levels of the vessel along the straightened volume. An optimal path finding method based on Dijkstra's algorithm was finally used to trace the correct path for the vessel of interest. Two and eight CTPA scans were randomly selected as training and test data sets, respectively. Forty volumes of interest (VOIs) containing "representative" vessels were manually segmented by a radiologist experienced in CTPA interpretation and used as reference standard. The results show that, for the 32 test VOIs, the average percentage volume error relative to the reference standard was improved from 32.9+/-10.2% using the MHES method to 9.9+/-7.9% using the MHES-CROP method. The accuracy of vessel segmentation was improved significantly (p<0.05). The intraclass correlation coefficient (ICC) of the segmented vessel volume between the automated segmentation and the reference standard was improved from 0.919 to 0.988. Quantitative comparison of the MHES method and the MHES-CROP method with the

  10. Assessment of statistical uncertainty analysis of joint refraction and reflection travel-time tomographic models applied to real data off the Nicaraguan margin.

    NASA Astrophysics Data System (ADS)

    Prada, M.; Sallarés, V.; Meléndez, A.; Ranero, C. R.; McIntosh, K.

    2010-05-01

    The wide-angle seismic modeling of crust and mantle is key to understand the structure and physical properties of the Earth's interior. However, a reliable interpretation of the obtained models requires having constraints on the model parameter uncertainties. For that reason, we analyze here the potential and limits of most common, Monte-Carlo-based, statistical uncertainty analysis schemes of velocity and reflector geometry models obtained by travel-time tomography of wide-angle seismic data. We have used a wide-angle seismic data set acquired off the Nicaragua convergent margin. The data correspond to a profile that runs parallel to the trench axis along the continental slope. It is 190 km long and includes 12 Ocean Bottom Hydrophones located 10-15 km apart. The data have been modeled following a joint refraction and reflection travel-time tomographic inversion to obtain a 2-D velocity field of the overriding plate as well as the location and geometry of the inter-plate boundary. The model shows a ~5 km thick sedimentary cover with velocities varying from 2 km/s to 3.5 km/s, overlying a ~12 km thick basement with velocities between 4 km/s and 6.5 km/s. Ray coverage shows that diving waves concentrate in the upper third of the model, whereas the two bottom thirds are covered only by reflections from the inter-plate boundary zone. This gives an idea of the areas where the model is likely to be better constrained by the data, but the ray coverage alone does not provide a measure of the accuracy of the results nor an idea of the significance of velocity-depth trade-off. To analyze the accuracy of the model we have implemented a Monte Carlo-like uncertainty analysis consisting of randomly varying an 1D velocity model, the depth of the floating reflector, and the picked arrival times, to generate a total of 100 2D reference models and perturbed data sets, to subsequently conduct an inversion for each model-data set pair. Theory states that, under certain conditions

  11. Combining ART and FBP for improved fidelity of tomographic BOS

    NASA Astrophysics Data System (ADS)

    Hartmann, Ulrich; Seume, Joerg R.

    2016-09-01

    Engine component defects along the hot-gas path (HGP) of jet engines influence the density distribution of the flow, and thus result in characteristic patterns in the exhaust jet. These characteristic patterns can be reconstructed with the optical background-oriented schlieren (BOS) method in a tomographic set-up, which in turn allows the identification of defects inside the engine through an exhaust jet analysis. The quality of the tomographic reconstruction strongly influences how easily defects can be detected inside the jet engine. In particular, the presence of high gradients in the reconstruction area has a strong impact on the reconstruction quality. An algebraic reconstruction algorithm (ART) is implemented and compared to a filtered-back projection (FBP) algorithm in terms of the capability of performing high-gradient tomographic BOS reconstructions. A combination of both algorithms is presented which significantly improves the reconstruction quality of high-gradient tomographic BOS in terms of artifact reduction. The combination of both algorithms is applied to both synthetic and real measurement data in this paper, in order to show possible applications and the achievable improvement of high-gradient tomographic BOS reconstructions.

  12. On the tomographic description of classical fields

    NASA Astrophysics Data System (ADS)

    Ibort, A.; López-Yela, A.; Man'ko, V. I.; Marmo, G.; Simoni, A.; Sudarshan, E. C. G.; Ventriglia, F.

    2012-03-01

    After a general description of the tomographic picture for classical systems, a tomographic description of free classical scalar fields is proposed both in a finite cavity and the continuum. The tomographic description is constructed in analogy with the classical tomographic picture of an ensemble of harmonic oscillators. The tomograms of a number of relevant states such as the canonical distribution, the classical counterpart of quantum coherent states and a new family of so-called Gauss-Laguerre states, are discussed. Finally the Liouville equation for field states is described in the tomographic picture offering an alternative description of the dynamics of the system that can be extended naturally to other fields.

  13. Expediting model-based optoacoustic reconstructions with tomographic symmetries

    SciTech Connect

    Lutzweiler, Christian; Deán-Ben, Xosé Luís; Razansky, Daniel

    2014-01-15

    Purpose: Image quantification in optoacoustic tomography implies the use of accurate forward models of excitation, propagation, and detection of optoacoustic signals while inversions with high spatial resolution usually involve very large matrices, leading to unreasonably long computation times. The development of fast and memory efficient model-based approaches represents then an important challenge to advance on the quantitative and dynamic imaging capabilities of tomographic optoacoustic imaging. Methods: Herein, a method for simplification and acceleration of model-based inversions, relying on inherent symmetries present in common tomographic acquisition geometries, has been introduced. The method is showcased for the case of cylindrical symmetries by using polar image discretization of the time-domain optoacoustic forward model combined with efficient storage and inversion strategies. Results: The suggested methodology is shown to render fast and accurate model-based inversions in both numerical simulations andpost mortem small animal experiments. In case of a full-view detection scheme, the memory requirements are reduced by one order of magnitude while high-resolution reconstructions are achieved at video rate. Conclusions: By considering the rotational symmetry present in many tomographic optoacoustic imaging systems, the proposed methodology allows exploiting the advantages of model-based algorithms with feasible computational requirements and fast reconstruction times, so that its convenience and general applicability in optoacoustic imaging systems with tomographic symmetries is anticipated.

  14. LASER APPLICATIONS IN MEDICINE: Analysis of distortions in the velocity profiles of suspension flows inside a light-scattering medium upon their reconstruction from the optical coherence Doppler tomograph signal

    NASA Astrophysics Data System (ADS)

    Bykov, A. V.; Kirillin, M. Yu; Priezzhev, A. V.

    2005-11-01

    Model signals from one and two plane flows of a particle suspension are obtained for an optical coherence Doppler tomograph (OCDT) by the Monte-Carlo method. The optical properties of particles mimic the properties of non-aggregating erythrocytes. The flows are considered in a stationary scattering medium with optical properties close to those of the skin. It is shown that, as the flow position depth increases, the flow velocity determined from the OCDT signal becomes smaller than the specified velocity and the reconstructed profile extends in the direction of the distant boundary, which is accompanied by the shift of its maximum. In the case of two flows, an increase in the velocity of the near-surface flow leads to the overestimated values of velocity of the reconstructed profile of the second flow. Numerical simulations were performed by using a multiprocessor parallel-architecture computer.

  15. [Fascioliasis hepatis--computed tomographic aspect].

    PubMed

    Goebel, N; Markwalder, K; Siegenthaler, W

    1984-12-01

    In a patient with liver fascioliasis (already excreting eggs with the faeces) a CT scan of the liver showed after i. v. contrast injection a relatively characteristic aspect with multiple, small, hypodense areas, partly in formations of bunches of grapes, partly in a street-like arrangement towards the portal vein - bile duct - areas. 9 months later the hypodense lesions had markedly decreased. PMID:6518725

  16. Analysis of bite marks in foodstuffs by computer tomography (cone beam CT)--3D reconstruction.

    PubMed

    Marques, Jeidson; Musse, Jamilly; Caetano, Catarina; Corte-Real, Francisco; Corte-Real, Ana Teresa

    2013-12-01

    The use of three-dimensional (3D) analysis of forensic evidence is highlighted in comparison with traditional methods. This three-dimensional analysis is based on the registration of the surface from a bitten object. The authors propose to use Cone Beam Computed Tomography (CBCT), which is used in dental practice, in order to study the surface and interior of bitten objects and dental casts of suspects. In this study, CBCT is applied to the analysis of bite marks in foodstuffs, which may be found in a forensic case scenario. 6 different types of foodstuffs were used: chocolate, cheese, apple, chewing gum, pizza and tart (flaky pastry and custard). The food was bitten into and dental casts of the possible suspects were made. The dental casts and bitten objects were registered using an x-ray source and the CBCT equipment iCAT® (Pennsylvania, EUA). The software InVivo5® (Anatomage Inc, EUA) was used to visualize and analyze the tomographic slices and 3D reconstructions of the objects. For each material an estimate of its density was assessed by two methods: HU values and specific gravity. All the used materials were successfully reconstructed as good quality 3D images. The relative densities of the materials in study were compared. Amongst the foodstuffs, the chocolate had the highest density (median value 100.5 HU and 1,36 g/cm(3)), while the pizza showed to have the lowest (median value -775 HU and 0,39 g/cm(3)), on both scales. Through tomographic slices and three-dimensional reconstructions it was possible to perform the metric analysis of the bite marks in all the foodstuffs, except for the pizza. These measurements could also be obtained from the dental casts. The depth of the bite mark was also successfully determined in all the foodstuffs except for the pizza. Cone Beam Computed Tomography has the potential to become an important tool for forensic sciences, namely for the registration and analysis of bite marks in foodstuffs that may be found in a crime

  17. Single-shot ultrafast tomographic imaging by spectral multiplexing

    NASA Astrophysics Data System (ADS)

    Matlis, N. H.; Axley, A.; Leemans, W. P.

    2012-10-01

    Computed tomography has profoundly impacted science, medicine and technology by using projection measurements scanned over multiple angles to permit cross-sectional imaging of an object. The application of computed tomography to moving or dynamically varying objects, however, has been limited by the temporal resolution of the technique, which is set by the time required to complete the scan. For objects that vary on ultrafast timescales, traditional scanning methods are not an option. Here we present a non-scanning method capable of resolving structure on femtosecond timescales by using spectral multiplexing of a single laser beam to perform tomographic imaging over a continuous range of angles simultaneously. We use this technique to demonstrate the first single-shot ultrafast computed tomography reconstructions and obtain previously inaccessible structure and position information for laser-induced plasma filaments. This development enables real-time tomographic imaging for ultrafast science, and offers a potential solution to the challenging problem of imaging through scattering surfaces.

  18. Aerodynamic analysis of Pegasus - Computations vs reality

    NASA Technical Reports Server (NTRS)

    Mendenhall, Michael R.; Lesieutre, Daniel J.; Whittaker, C. H.; Curry, Robert E.; Moulton, Bryan

    1993-01-01

    Pegasus, a three-stage, air-launched, winged space booster was developed to provide fast and efficient commercial launch services for small satellites. The aerodynamic design and analysis of Pegasus was conducted without benefit of wind tunnel tests using only computational aerodynamic and fluid dynamic methods. Flight test data from the first two operational flights of Pegasus are now available, and they provide an opportunity to validate the accuracy of the predicted pre-flight aerodynamic characteristics. Comparisons of measured and predicted flight characteristics are presented and discussed. Results show that the computational methods provide reasonable aerodynamic design information with acceptable margins. Post-flight analyses illustrate certain areas in which improvements are desired.

  19. Semiconductor Device Analysis on Personal Computers

    Energy Science and Technology Software Center (ESTSC)

    1993-02-08

    PC-1D models the internal operation of bipolar semiconductor devices by solving for the concentrations and quasi-one-dimensional flow of electrons and holes resulting from either electrical or optical excitation. PC-1D uses the same detailed physical models incorporated in mainframe computer programs, yet runs efficiently on personal computers. PC-1D was originally developed with DOE funding to analyze solar cells. That continues to be its primary mode of usage, with registered copies in regular use at more thanmore » 100 locations worldwide. The program has been successfully applied to the analysis of silicon, gallium-arsenide, and indium-phosphide solar cells. The program is also suitable for modeling bipolar transistors and diodes, including heterojunction devices. Its easy-to-use graphical interface makes it useful as a teaching tool as well.« less

  20. Meaningful statistical analysis of large computational clusters.

    SciTech Connect

    Gentile, Ann C.; Marzouk, Youssef M.; Brandt, James M.; Pebay, Philippe Pierre

    2005-07-01

    Effective monitoring of large computational clusters demands the analysis of a vast amount of raw data from a large number of machines. The fundamental interactions of the system are not, however, well-defined, making it difficult to draw meaningful conclusions from this data, even if one were able to efficiently handle and process it. In this paper we show that computational clusters, because they are comprised of a large number of identical machines, behave in a statistically meaningful fashion. We therefore can employ normal statistical methods to derive information about individual systems and their environment and to detect problems sooner than with traditional mechanisms. We discuss design details necessary to use these methods on a large system in a timely and low-impact fashion.

  1. Computational frameworks for discrete Gabor analysis

    NASA Astrophysics Data System (ADS)

    Strohmer, Thomas

    1997-10-01

    The Gabor transform yields a discrete representation of a signal in the phase space. Since the Gabor transform is non-orthogonal, efficient reconstruction of a signal from its phase space samples is not straightforward and involves the computation of the so- called dual Gabor function. We present a unifying approach to the derivation of numerical algorithms for discrete Gabor analysis, based on unitary matrix factorization. The factorization point of view is notably useful for the design of efficient numerical algorithms. This presentation is the first systematic account of its kind. In particular, it is shown that different algorithms for the computation of the dual window correspond to different factorizations of the frame operator. Simple number theoretic conditions on the time-frequency lattice parameters imply additional structural properties of the frame operator.

  2. CT-guided Irreversible Electroporation in an Acute Porcine Liver Model: Effect of Previous Transarterial Iodized Oil Tissue Marking on Technical Parameters, 3D Computed Tomographic Rendering of the Electroporation Zone, and Histopathology

    SciTech Connect

    Sommer, C. M.; Fritz, S.; Vollherbst, D.; Zelzer, S.; Wachter, M. F. Bellemann, N. Gockner, T. Mokry, T. Schmitz, A.; Aulmann, S.; Stampfl, U.; Pereira, P.; Kauczor, H. U.; Werner, J.; Radeleff, B. A.

    2015-02-15

    PurposeTo evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance.MethodsAfter Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann–Whitney test. Histopathological differences were assessed.ResultsMean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm{sup 3}, and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm{sup 3}, and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone.ConclusionThere is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver.

  3. An efficient and accurate approach to MTE-MART for time-resolved tomographic PIV

    NASA Astrophysics Data System (ADS)

    Lynch, K. P.; Scarano, F.

    2015-03-01

    The motion-tracking-enhanced MART (MTE-MART; Novara et al. in Meas Sci Technol 21:035401, 2010) has demonstrated the potential to increase the accuracy of tomographic PIV by the combined use of a short sequence of non-simultaneous recordings. A clear bottleneck of the MTE-MART technique has been its computational cost. For large datasets comprising time-resolved sequences, MTE-MART becomes unaffordable and has been barely applied even for the analysis of densely seeded tomographic PIV datasets. A novel implementation is proposed for tomographic PIV image sequences, which strongly reduces the computational burden of MTE-MART, possibly below that of regular MART. The method is a sequential algorithm that produces a time-marching estimation of the object intensity field based on an enhanced guess, which is built upon the object reconstructed at the previous time instant. As the method becomes effective after a number of snapshots (typically 5-10), the sequential MTE-MART (SMTE) is most suited for time-resolved sequences. The computational cost reduction due to SMTE simply stems from the fewer MART iterations required for each time instant. Moreover, the method yields superior reconstruction quality and higher velocity field measurement precision when compared with both MART and MTE-MART. The working principle is assessed in terms of computational effort, reconstruction quality and velocity field accuracy with both synthetic time-resolved tomographic images of a turbulent boundary layer and two experimental databases documented in the literature. The first is the time-resolved data of flow past an airfoil trailing edge used in the study of Novara and Scarano (Exp Fluids 52:1027-1041, 2012); the second is a swirling jet in a water flow. In both cases, the effective elimination of ghost particles is demonstrated in number and intensity within a short temporal transient of 5-10 frames, depending on the seeding density. The increased value of the velocity space

  4. Motion tracking-enhanced MART for tomographic PIV

    NASA Astrophysics Data System (ADS)

    Novara, Matteo; Joost Batenburg, Kees; Scarano, Fulvio

    2010-03-01

    A novel technique to increase the accuracy of multiplicative algebraic reconstruction technique (MART) reconstruction from tomographic particle image velocimetry (PIV) recordings at higher seeding density than currently possible is presented. The motion tracking enhancement (MTE) method is based on the combined utilization of images from two or more exposures to enhance the reconstruction of individual intensity fields. The working principle is first introduced qualitatively, and the mathematical background is given that explains how the MART reconstruction can be improved on the basis of an improved first guess object obtained from the combination of non-simultaneous views reduced to the same time instant deforming the 3D objects by an estimate of the particle motion field. The performances of MTE are quantitatively evaluated by numerical simulation of the imaging, reconstruction and image correlation processes. The cases of two or more exposures obtained from time-resolved experiments are considered. The iterative application of MTE appears to significantly improve the reconstruction quality, first by decreasing the intensity of the ghost images and second, by increasing the intensity and the reconstruction precision for the actual particles. Based on computer simulations, the maximum imaged seeding density that can be dealt with is tripled with respect to the MART analysis applied to a single exposure. The analysis also illustrates that the maximum effect of the MTE method is comparable to that of doubling the number of cameras in the tomographic system. Experiments performed on a transitional jet at Re = 5000 apply the MTE method to double-frame recordings. The velocity measurement precision is increased for a system with fewer views (two or three cameras compared with four cameras). The ghost particles' intensity is also visibly reduced although to a lesser extent with respect to the computer simulations. The velocity and vorticity field obtained from a three

  5. FORTRAN computer program for seismic risk analysis

    USGS Publications Warehouse

    McGuire, Robin K.

    1976-01-01

    A program for seismic risk analysis is described which combines generality of application, efficiency and accuracy of operation, and the advantage of small storage requirements. The theoretical basis for the program is first reviewed, and the computational algorithms used to apply this theory are described. The information required for running the program is listed. Published attenuation functions describing the variation with earthquake magnitude and distance of expected values for various ground motion parameters are summarized for reference by the program user. Finally, suggestions for use of the program are made, an example problem is described (along with example problem input and output) and the program is listed.

  6. Tomographic bioluminescence imaging by an iteratively re-weighted minimization

    NASA Astrophysics Data System (ADS)

    Wu, Ping; Liu, Kai; Xue, Zhenwen; Guo, Wei; Qin, Chenghu; Tian, Jie

    2012-03-01

    Tomographic bioluminescence imaging (TBI), with visible light emission in living organisms, is an effective way of molecular imaging, which allows for the study of ongoing tumor biological processes in vivo and non-invasively. This newly developed technology enables three-dimensional accuracy localization and quantitative analysis of the target tumor cells in small animal via reconstructing the images acquired by the high-resolution imaging system. Due to the difficulty of reconstruction, which is often referred to an ill-posed inverse problem, continuous efforts are still made to find more practical and efficient approaches. In this paper, an iteratively re-weighted minimization (IRM) has been applied to reconstruct the entire source distribution, which is known as sparse signals, inside the target tissue with the limited outgoing photon density on its boundary. By introducing a weight function into the objective function, we convert the lp norm problem into a more simple form of l2 norm to reduce the computational complexity. The weight function is updated in each iterative step to compute the final optimal solution more efficiently. This method is proved to be robust to different parameters, and mouse experiments are conducted to validate the feasibility of IRM approach, which is also reliable at whole-body imaging.

  7. Computer network environment planning and analysis

    NASA Technical Reports Server (NTRS)

    Dalphin, John F.

    1989-01-01

    The GSFC Computer Network Environment provides a broadband RF cable between campus buildings and ethernet spines in buildings for the interlinking of Local Area Networks (LANs). This system provides terminal and computer linkage among host and user systems thereby providing E-mail services, file exchange capability, and certain distributed computing opportunities. The Environment is designed to be transparent and supports multiple protocols. Networking at Goddard has a short history and has been under coordinated control of a Network Steering Committee for slightly more than two years; network growth has been rapid with more than 1500 nodes currently addressed and greater expansion expected. A new RF cable system with a different topology is being installed during summer 1989; consideration of a fiber optics system for the future will begin soon. Summmer study was directed toward Network Steering Committee operation and planning plus consideration of Center Network Environment analysis and modeling. Biweekly Steering Committee meetings were attended to learn the background of the network and the concerns of those managing it. Suggestions for historical data gathering have been made to support future planning and modeling. Data Systems Dynamic Simulator, a simulation package developed at NASA and maintained at GSFC was studied as a possible modeling tool for the network environment. A modeling concept based on a hierarchical model was hypothesized for further development. Such a model would allow input of newly updated parameters and would provide an estimation of the behavior of the network.

  8. Advanced Ultrasonic Tomograph of Children's Bones

    NASA Astrophysics Data System (ADS)

    Lasaygues, Philippe; Lefebvre, Jean-Pierre; Guillermin, Régine; Kaftandjian, Valérie; Berteau, Jean-Philippe; Pithioux, Martine; Petit, Philippe

    This study deals with the development of an experimental device for performing ultrasonic computed tomography (UCT) on bone in pediatric degrees. The children's bone tomographs obtained in this study, were based on the use of a multiplexed 2-D ring antenna (1 MHz and 3 MHz) designed for performing electronic and mechanical scanning. Although this approach is known to be a potentially valuable means of imaging objects with similar acoustical impedances, problems arise when quantitative images of more highly contrasted media such as bones are required. Various strategies and various mathematical procedures for modeling the wave propagation based on Born approximations have been developed at our laboratory, which are suitable for use with pediatric cases. Inversions of the experimental data obtained are presented.

  9. Experimental analysis of computer system dependability

    NASA Technical Reports Server (NTRS)

    Iyer, Ravishankar, K.; Tang, Dong

    1993-01-01

    This paper reviews an area which has evolved over the past 15 years: experimental analysis of computer system dependability. Methodologies and advances are discussed for three basic approaches used in the area: simulated fault injection, physical fault injection, and measurement-based analysis. The three approaches are suited, respectively, to dependability evaluation in the three phases of a system's life: design phase, prototype phase, and operational phase. Before the discussion of these phases, several statistical techniques used in the area are introduced. For each phase, a classification of research methods or study topics is outlined, followed by discussion of these methods or topics as well as representative studies. The statistical techniques introduced include the estimation of parameters and confidence intervals, probability distribution characterization, and several multivariate analysis methods. Importance sampling, a statistical technique used to accelerate Monte Carlo simulation, is also introduced. The discussion of simulated fault injection covers electrical-level, logic-level, and function-level fault injection methods as well as representative simulation environments such as FOCUS and DEPEND. The discussion of physical fault injection covers hardware, software, and radiation fault injection methods as well as several software and hybrid tools including FIAT, FERARI, HYBRID, and FINE. The discussion of measurement-based analysis covers measurement and data processing techniques, basic error characterization, dependency analysis, Markov reward modeling, software-dependability, and fault diagnosis. The discussion involves several important issues studies in the area, including fault models, fast simulation techniques, workload/failure dependency, correlated failures, and software fault tolerance.

  10. Tomoeye: A Matlab package for visualization of three-dimensional tomographic models

    NASA Astrophysics Data System (ADS)

    Gorbatov, A.; Limaye, A.; Sambridge, M.

    2004-04-01

    The use of seismic imaging techniques is widespread. Numerous three-dimensional (3-D) tomographic models have been presented over the last 30 years and subsequently analyzed by a wider community of seismologists, geodynamicists, mineral physicists, and geochemists. However, platform-independent, open source, user-friendly software for interactive exploration of tomographic models does not exist. Here, we present a package for interactive visualization, analysis, and presentation of tomographic models. Using a set of four Matlab programs, multiscale tomographic models can be explored in Cartesian or spherical coordinate systems; data subsets can be extracted and combined; publication-quality figures can be produced; and Virtual Reality Modeling Language (VRML) models can be produced for 3-D visualization and publication on the World Wide Web. This type of freely available software package will encourage the distribution of tomographic models in a standardized form for independent peer review by the research community.

  11. Tomographic reconstruction of polar plumes

    NASA Astrophysics Data System (ADS)

    Auchère, F.; Guennou, C.; Barbey, N.

    2012-06-01

    We present a tomographic reconstruction of polar plumes as observed in the Extreme Ultraviolet in January 2010. Plumes are elusive structures visible in polar coronal holes that may play an important role in the acceleration of the solar wind. However, despite numerous observations, little is irrefutably known about them. Because of line of sight effects, even their geometry is subject to debate. Are they genuine cylindrical features of the corona or are they only chance alignments along the line of sight? Tomography provides a means to reconstruct the volume of an optically thin object from a set of observations taken from different vantage points. In the case of the Sun, these are typically obtained by using a solar rotation worth of images, which limits the ability to reconstruct short lived structures. We present here a tomographic inversion of the solar corona obtained using only 6 days of data. This is achieved by using simultaneously three space telescopes (EUVI/STEREO and SWAP/PROBA2) in a very specific orbital configuration. The result is the shortest possible tomographic snapshot of polar plumes. The 3D reconstruction shows both quasi-cylindrical plumes and a network pattern that can mimic them by line of sight superimpositions. This suggests that the controversy on plume geometry is due to the coexistence of both types of structures.

  12. Good relationships between computational image analysis and radiological physics

    SciTech Connect

    Arimura, Hidetaka; Kamezawa, Hidemi; Jin, Ze; Nakamoto, Takahiro; Soufi, Mazen

    2015-09-30

    Good relationships between computational image analysis and radiological physics have been constructed for increasing the accuracy of medical diagnostic imaging and radiation therapy in radiological physics. Computational image analysis has been established based on applied mathematics, physics, and engineering. This review paper will introduce how computational image analysis is useful in radiation therapy with respect to radiological physics.

  13. Good relationships between computational image analysis and radiological physics

    NASA Astrophysics Data System (ADS)

    Arimura, Hidetaka; Kamezawa, Hidemi; Jin, Ze; Nakamoto, Takahiro; Soufi, Mazen

    2015-09-01

    Good relationships between computational image analysis and radiological physics have been constructed for increasing the accuracy of medical diagnostic imaging and radiation therapy in radiological physics. Computational image analysis has been established based on applied mathematics, physics, and engineering. This review paper will introduce how computational image analysis is useful in radiation therapy with respect to radiological physics.

  14. Neural network analysis of crosshole tomographic images: The seismic signature of gas hydrate bearing sediments in the Mackenzie Delta (NW Canada)

    NASA Astrophysics Data System (ADS)

    Bauer, K.; Pratt, R. G.; Haberland, C.; Weber, M.

    2008-10-01

    Crosshole seismic experiments were conducted to study the in-situ properties of gas hydrate bearing sediments (GHBS) in the Mackenzie Delta (NW Canada). Seismic tomography provided images of P velocity, anisotropy, and attenuation. Self-organizing maps (SOM) are powerful neural network techniques to classify and interpret multi-attribute data sets. The coincident tomographic images are translated to a set of data vectors in order to train a Kohonen layer. The total gradient of the model vectors is determined for the trained SOM and a watershed segmentation algorithm is used to visualize and map the lithological clusters with well-defined seismic signatures. Application to the Mallik data reveals four major litho-types: (1) GHBS, (2) sands, (3) shale/coal interlayering, and (4) silt. The signature of seismic P wave characteristics distinguished for the GHBS (high velocities, strong anisotropy and attenuation) is new and can be used for new exploration strategies to map and quantify gas hydrates.

  15. Image processing pipeline for synchrotron-radiation-based tomographic microscopy.

    PubMed

    Hintermüller, C; Marone, F; Isenegger, A; Stampanoni, M

    2010-07-01

    With synchrotron-radiation-based tomographic microscopy, three-dimensional structures down to the micrometer level can be visualized. Tomographic data sets typically consist of 1000 to 1500 projections of 1024 x 1024 to 2048 x 2048 pixels and are acquired in 5-15 min. A processing pipeline has been developed to handle this large amount of data efficiently and to reconstruct the tomographic volume within a few minutes after the end of a scan. Just a few seconds after the raw data have been acquired, a selection of reconstructed slices is accessible through a web interface for preview and to fine tune the reconstruction parameters. The same interface allows initiation and control of the reconstruction process on the computer cluster. By integrating all programs and tools, required for tomographic reconstruction into the pipeline, the necessary user interaction is reduced to a minimum. The modularity of the pipeline allows functionality for new scan protocols to be added, such as an extended field of view, or new physical signals such as phase-contrast or dark-field imaging etc. PMID:20567088

  16. A novel flexible clinical multiphoton tomograph for early melanoma detection, skin analysis, testing of anti-age products, and in situ nanoparticle tracking

    NASA Astrophysics Data System (ADS)

    Weinigel, Martin; Breunig, Hans Georg; Gregory, Axel; Fischer, Peter; Kellner-Höfer, Marcel; Bückle, Rainer; König, Karsten

    2010-02-01

    High-resolution 3D microscopy based on multiphoton induced autofluorescence and second harmonic generation have been introduced in 1990. 13 years later, CE-marked clinical multiphoton systems for 3D imaging of human skin with subcellular resolution have first been launched by JenLab company with the tomography DermaInspect®. This year, the second generation of clinical multiphoton tomographs was introduced. The novel multiphoton tomograph MPTflex, equipped with a flexible articulated optical arm, provides an increased flexibility and accessibility especially for clinical and cosmetical examinations. Improved image quality and signal to noise ratio (SNR) are achieved by a very short source-drain spacing, by larger active areas of the detectors and by single photon counting (SPC) technology. Shorter image acquisition time due to improved image quality reduces artifacts and simplifies the operation of the system. The compact folded optical design and the light-weight structure of the optical head eases the handling. Dual channel detectors enable to distinguish between intratissue elastic fibers and collagenous structures simultaneously. Through the use of piezo-driven optics a stack of optical cross-sections (optical sectioning) can be acquired and 3D imaging can be performed. The multiphoton excitation of biomolecules like NAD(P)H, flavins, porphyrins, elastin, and melanin is done by picojoule femtosecond laser pulses from an tunable turn-key femtosescond near infrared laser system. The ability for rapid high-quality image acquisition, the user-friendly operation of the system and the compact and flexible design qualifies this system to be used for melanoma detection, diagnostics of dermatological disorders, cosmetic research and skin aging measurements as well as in situ drug monitoring and animal research.

  17. Analysis of the fetal placental vascular tree by X-ray micro-computed tomography.

    PubMed

    Langheinrich, A C; Wienhard, J; Vormann, S; Hau, B; Bohle, R M; Zygmunt, M

    2004-01-01

    The current understanding of the placental vascular tree largely derives from time-consuming morphometric analyses performed by conventional histology, electron microscopy of corrosion casts and three-dimensional reconstructions based on physical tissue sections. In the present study, we demonstrate for the first time that micro-computed tomography (micro-CT) emerges as a new, non-destructive and fast tool for imaging and quantifying fetoplacental vasculature. Term placentae (n=5) were perfused with contrast agent consisting of barium-sulfate, gelatine and thymol shortly after Caesarean-section-delivery. Samples (1 cm(3)) from eight different regions of the placenta were subsequently scanned in a micro-CT. Using tomographic reconstruction algorithms, three dimensional images were obtained by micro-CT allowing total stereoscopic visualization and continuous quantitative analysis of the vascular structure of the investigated samples. These samples were compared regarding vascular surface (VS) and vascular density (vascular volume fraction, TCVF). Quantitative assessment showed an average vascular density of 16 per cent (SD+/-0.4) and a vascular surface of 475 mm(2)(SD+/-8) per total tissue volume (including intervillous space) of 125 mm(3). Micro-CT image-analysis showed no significant differences in the fetal vascularization among term placentae. Micro-CT imaging is feasible for imaging and analysis of the villous vascular tree, allows further morphologic studies and immunohistochemistry of the placental specimens and may emerge as an additional tool in the investigation of the physiology and pathophysiology of the placental vasculature. PMID:15013644

  18. Transmission images and evaluation of tomographic imaging based scattered radiation from biological materials using 10, 15, 20 and 25 keV synchrotron X-rays: An analysis in terms of optimum energy

    SciTech Connect

    Rao, Donepudi V.; Akatsuka, Takao; Tromba, Giuliana

    2004-05-12

    Transmission images and tomographic imaging based scattered radiation is evaluated from biological materials, for example, Polyethylene, Poly carbonate, Plexiglas and Nylon using 10, 15, 20 and 25 keV synchrotron X-rays. The SYRMEP facility at Elettra,Trieste, Italy and the associated detection system has been used for the image acquisition. The scattered radiation is detected for each sample at three energies at an angle of 90 deg. using Si-Pin detector coupled to a multi-channel analyzer. The contribution of transmitted, Compton and fluorescence photons are assessed for a test phantom of small dimensions. The optimum analysis is performed with the use of the dimensions of the sample and detected radiation at various energies.

  19. Distributed Design and Analysis of Computer Experiments

    SciTech Connect

    Doak, Justin

    2002-11-11

    DDACE is a C++ object-oriented software library for the design and analysis of computer experiments. DDACE can be used to generate samples from a variety of sampling techniques. These samples may be used as input to a application code. DDACE also contains statistical tools such as response surface models and correlation coefficients to analyze input/output relationships between variables in an application code. DDACE can generate input values for uncertain variables within a user's application. For example, a user might like to vary a temperature variable as well as some material variables in a series of simulations. Through the series of simulations the user might be looking for optimal settings of parameters based on some user criteria. Or the user may be interested in the sensitivity to input variability shown by an output variable. In either case, the user may provide information about the suspected ranges and distributions of a set of input variables, along with a sampling scheme, and DDACE will generate input points based on these specifications. The input values generated by DDACE and the one or more outputs computed through the user's application code can be analyzed with a variety of statistical methods. This can lead to a wealth of information about the relationships between the variables in the problem. While statistical and mathematical packages may be employeed to carry out the analysis on the input/output relationships, DDACE also contains some tools for analyzing the simulation data. DDACE incorporates a software package called MARS (Multivariate Adaptive Regression Splines), developed by Jerome Friedman. MARS is used for generating a spline surface fit of the data. With MARS, a model simplification may be calculated using the input and corresponding output, values for the user's application problem. The MARS grid data may be used for generating 3-dimensional response surface plots of the simulation data. DDACE also contains an implementation of an

  20. Distributed Design and Analysis of Computer Experiments

    Energy Science and Technology Software Center (ESTSC)

    2002-11-11

    DDACE is a C++ object-oriented software library for the design and analysis of computer experiments. DDACE can be used to generate samples from a variety of sampling techniques. These samples may be used as input to a application code. DDACE also contains statistical tools such as response surface models and correlation coefficients to analyze input/output relationships between variables in an application code. DDACE can generate input values for uncertain variables within a user's application. Formore » example, a user might like to vary a temperature variable as well as some material variables in a series of simulations. Through the series of simulations the user might be looking for optimal settings of parameters based on some user criteria. Or the user may be interested in the sensitivity to input variability shown by an output variable. In either case, the user may provide information about the suspected ranges and distributions of a set of input variables, along with a sampling scheme, and DDACE will generate input points based on these specifications. The input values generated by DDACE and the one or more outputs computed through the user's application code can be analyzed with a variety of statistical methods. This can lead to a wealth of information about the relationships between the variables in the problem. While statistical and mathematical packages may be employeed to carry out the analysis on the input/output relationships, DDACE also contains some tools for analyzing the simulation data. DDACE incorporates a software package called MARS (Multivariate Adaptive Regression Splines), developed by Jerome Friedman. MARS is used for generating a spline surface fit of the data. With MARS, a model simplification may be calculated using the input and corresponding output, values for the user's application problem. The MARS grid data may be used for generating 3-dimensional response surface plots of the simulation data. DDACE also contains an implementation

  1. Probabilistic Computational Methods in Structural Failure Analysis

    NASA Astrophysics Data System (ADS)

    Krejsa, Martin; Kralik, Juraj

    2015-12-01

    Probabilistic methods are used in engineering where a computational model contains random variables. Each random variable in the probabilistic calculations contains uncertainties. Typical sources of uncertainties are properties of the material and production and/or assembly inaccuracies in the geometry or the environment where the structure should be located. The paper is focused on methods for the calculations of failure probabilities in structural failure and reliability analysis with special attention on newly developed probabilistic method: Direct Optimized Probabilistic Calculation (DOProC), which is highly efficient in terms of calculation time and the accuracy of the solution. The novelty of the proposed method lies in an optimized numerical integration that does not require any simulation technique. The algorithm has been implemented in mentioned software applications, and has been used several times in probabilistic tasks and probabilistic reliability assessments.

  2. Computational based functional analysis of Bacillus phytases.

    PubMed

    Verma, Anukriti; Singh, Vinay Kumar; Gaur, Smriti

    2016-02-01

    Phytase is an enzyme which catalyzes the total hydrolysis of phytate to less phosphorylated myo-inositol derivatives and inorganic phosphate and digests the undigestable phytate part present in seeds and grains and therefore provides digestible phosphorus, calcium and other mineral nutrients. Phytases are frequently added to the feed of monogastric animals so that bioavailability of phytic acid-bound phosphate increases, ultimately enhancing the nutritional value of diets. The Bacillus phytase is very suitable to be used in animal feed because of its optimum pH with excellent thermal stability. Present study is aimed to perform an in silico comparative characterization and functional analysis of phytases from Bacillus amyloliquefaciens to explore physico-chemical properties using various bio-computational tools. All proteins are acidic and thermostable and can be used as suitable candidates in the feed industry. PMID:26672917

  3. Review of Computational Stirling Analysis Methods

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger W.; Wilson, Scott D.; Tew, Roy C.

    2004-01-01

    Nuclear thermal to electric power conversion carries the promise of longer duration missions and higher scientific data transmission rates back to Earth for both Mars rovers and deep space missions. A free-piston Stirling convertor is a candidate technology that is considered an efficient and reliable power conversion device for such purposes. While already very efficient, it is believed that better Stirling engines can be developed if the losses inherent its current designs could be better understood. However, they are difficult to instrument and so efforts are underway to simulate a complete Stirling engine numerically. This has only recently been attempted and a review of the methods leading up to and including such computational analysis is presented. And finally it is proposed that the quality and depth of Stirling loss understanding may be improved by utilizing the higher fidelity and efficiency of recently developed numerical methods. One such method, the Ultra HI-Fl technique is presented in detail.

  4. Quantum correlations and tomographic representation

    NASA Astrophysics Data System (ADS)

    Man'ko, O. V.; Chernega, V. N.

    2013-07-01

    We review the probabilistic representation of quantum mechanics within which states are described by the probability distribution rather than by the wavefunction and density matrix. Uncertainty relations have been obtained in the form of integral inequalities containing measurable optical tomograms of quantum states. Formulas for the transition probabilities and purity parameter have been derived in terms of the tomographic probability distributions. Inequalities for Shannon and Rényi entropies associated with quantum tomograms have been obtained. A scheme of the star product of tomograms has been developed.

  5. Organ and effective doses in newborns and infants undergoing voiding cystourethrograms (VCUG): A comparison of stylized and tomographic phantoms

    SciTech Connect

    Pazik, Frank D.; Staton, Robert J.; Williams, Jonathon L.; Arreola, Manuel M.; Hintenlang, David E.; Bolch, Wesley E.

    2007-01-15

    The time-sequence videotape-analysis methodology, developed [Sulieman et al., Radiology 178, 653-658 (1991)] for use in tissue dose estimations in adult fluoroscopy examinations and utilized [Bolch et al., Med. Phys. 30, 667-680 (2003)] for analog fluoroscopy in newborn patients, has been extended to the study of digital fluoroscopic examinations of the urinary bladder in newborn and infant female patients. Individual frames of the fluoroscopic and radiographic video were analyzed with respect to unique combinations of field size, field center, projection, tube potential, and tube current (mA), and integral tube current (mAs), respectively. The dosimetry study was conducted on five female patients of ages ranging from four-days to 66 days. For each patient, three different phantoms were utilized: a stylized computational phantom of the reference newborn (3.5 kg), a tomographic computational phantom of the reference newborn (3.5 kg), and (3) a tomographic computational phantom uniformly rescaled to match patient total-body mass. The latter phantom set circumvented the need for mass-dependent rescaling of recorded technique factors (kVp, mA, mAs, etc.), and thus represented the highest degree of patient specificity in the individual organ dose assessment. Effective dose values for the voiding cystourethrogram examination ranged from 0.6 to 3.2 mSv, with a mean and standard deviation of 1.8{+-}0.9 mSv. The ovary and colon equivalent doses contributed in total {approx}65%-80% of the effective dose in these fluoroscopy studies. Percent differences in the effective dose assessed using the two tomographic phantoms (one fixed at 3.5 kg with rescaled technique factors rescaled and one physically rescaled to individual patient masses with no adjustment of recorded technique factors) ranged for -49% to +15%. Percent differences in effective dose found using the 3.5 kg stylized phantom and the 3.5 kg tomographic phantom, both with patient-specific rescaling of technique

  6. Analysis on the security of cloud computing

    NASA Astrophysics Data System (ADS)

    He, Zhonglin; He, Yuhua

    2011-02-01

    Cloud computing is a new technology, which is the fusion of computer technology and Internet development. It will lead the revolution of IT and information field. However, in cloud computing data and application software is stored at large data centers, and the management of data and service is not completely trustable, resulting in safety problems, which is the difficult point to improve the quality of cloud service. This paper briefly introduces the concept of cloud computing. Considering the characteristics of cloud computing, it constructs the security architecture of cloud computing. At the same time, with an eye toward the security threats cloud computing faces, several corresponding strategies are provided from the aspect of cloud computing users and service providers.

  7. Computer Analysis of a Physical Pendulum.

    ERIC Educational Resources Information Center

    Priest, Joseph; Potts, Larry

    1990-01-01

    The interfacing of a physical pendulum to an Apple IIe computer and the physic instruction associated with it are discussed. Laboratory procedures, software commands, and computations used in this lesson are described. (CW)

  8. Performance Analysis of Cloud Computing Architectures Using Discrete Event Simulation

    NASA Technical Reports Server (NTRS)

    Stocker, John C.; Golomb, Andrew M.

    2011-01-01

    Cloud computing offers the economic benefit of on-demand resource allocation to meet changing enterprise computing needs. However, the flexibility of cloud computing is disadvantaged when compared to traditional hosting in providing predictable application and service performance. Cloud computing relies on resource scheduling in a virtualized network-centric server environment, which makes static performance analysis infeasible. We developed a discrete event simulation model to evaluate the overall effectiveness of organizations in executing their workflow in traditional and cloud computing architectures. The two part model framework characterizes both the demand using a probability distribution for each type of service request as well as enterprise computing resource constraints. Our simulations provide quantitative analysis to design and provision computing architectures that maximize overall mission effectiveness. We share our analysis of key resource constraints in cloud computing architectures and findings on the appropriateness of cloud computing in various applications.

  9. Computing in Qualitative Analysis: A Healthy Development?

    ERIC Educational Resources Information Center

    Richards, Lyn; Richards, Tom

    1991-01-01

    Discusses the potential impact of computers in qualitative health research. Describes the original goals, design, and implementation of NUDIST, a qualitative computing software. Argues for evaluation of the impact of computer techniques and for an opening of debate among program developers and users to address the purposes and power of computing…

  10. Linear adaptive noise-reduction filters for tomographic imaging: Optimizing for minimum mean square error

    SciTech Connect

    Sun, W Y

    1993-04-01

    This thesis solves the problem of finding the optimal linear noise-reduction filter for linear tomographic image reconstruction. The optimization is data dependent and results in minimizing the mean-square error of the reconstructed image. The error is defined as the difference between the result and the best possible reconstruction. Applications for the optimal filter include reconstructions of positron emission tomographic (PET), X-ray computed tomographic, single-photon emission tomographic, and nuclear magnetic resonance imaging. Using high resolution PET as an example, the optimal filter is derived and presented for the convolution backprojection, Moore-Penrose pseudoinverse, and the natural-pixel basis set reconstruction methods. Simulations and experimental results are presented for the convolution backprojection method.

  11. Ferrofluids: Modeling, numerical analysis, and scientific computation

    NASA Astrophysics Data System (ADS)

    Tomas, Ignacio

    This dissertation presents some developments in the Numerical Analysis of Partial Differential Equations (PDEs) describing the behavior of ferrofluids. The most widely accepted PDE model for ferrofluids is the Micropolar model proposed by R.E. Rosensweig. The Micropolar Navier-Stokes Equations (MNSE) is a subsystem of PDEs within the Rosensweig model. Being a simplified version of the much bigger system of PDEs proposed by Rosensweig, the MNSE are a natural starting point of this thesis. The MNSE couple linear velocity u, angular velocity w, and pressure p. We propose and analyze a first-order semi-implicit fully-discrete scheme for the MNSE, which decouples the computation of the linear and angular velocities, is unconditionally stable and delivers optimal convergence rates under assumptions analogous to those used for the Navier-Stokes equations. Moving onto the much more complex Rosensweig's model, we provide a definition (approximation) for the effective magnetizing field h, and explain the assumptions behind this definition. Unlike previous definitions available in the literature, this new definition is able to accommodate the effect of external magnetic fields. Using this definition we setup the system of PDEs coupling linear velocity u, pressure p, angular velocity w, magnetization m, and magnetic potential ϕ We show that this system is energy-stable and devise a numerical scheme that mimics the same stability property. We prove that solutions of the numerical scheme always exist and, under certain simplifying assumptions, that the discrete solutions converge. A notable outcome of the analysis of the numerical scheme for the Rosensweig's model is the choice of finite element spaces that allow the construction of an energy-stable scheme. Finally, with the lessons learned from Rosensweig's model, we develop a diffuse-interface model describing the behavior of two-phase ferrofluid flows and present an energy-stable numerical scheme for this model. For a

  12. TAIR- TRANSONIC AIRFOIL ANALYSIS COMPUTER CODE

    NASA Technical Reports Server (NTRS)

    Dougherty, F. C.

    1994-01-01

    The Transonic Airfoil analysis computer code, TAIR, was developed to employ a fast, fully implicit algorithm to solve the conservative full-potential equation for the steady transonic flow field about an arbitrary airfoil immersed in a subsonic free stream. The full-potential formulation is considered exact under the assumptions of irrotational, isentropic, and inviscid flow. These assumptions are valid for a wide range of practical transonic flows typical of modern aircraft cruise conditions. The primary features of TAIR include: a new fully implicit iteration scheme which is typically many times faster than classical successive line overrelaxation algorithms; a new, reliable artifical density spatial differencing scheme treating the conservative form of the full-potential equation; and a numerical mapping procedure capable of generating curvilinear, body-fitted finite-difference grids about arbitrary airfoil geometries. Three aspects emphasized during the development of the TAIR code were reliability, simplicity, and speed. The reliability of TAIR comes from two sources: the new algorithm employed and the implementation of effective convergence monitoring logic. TAIR achieves ease of use by employing a "default mode" that greatly simplifies code operation, especially by inexperienced users, and many useful options including: several airfoil-geometry input options, flexible user controls over program output, and a multiple solution capability. The speed of the TAIR code is attributed to the new algorithm and the manner in which it has been implemented. Input to the TAIR program consists of airfoil coordinates, aerodynamic and flow-field convergence parameters, and geometric and grid convergence parameters. The airfoil coordinates for many airfoil shapes can be generated in TAIR from just a few input parameters. Most of the other input parameters have default values which allow the user to run an analysis in the default mode by specifing only a few input parameters

  13. Downscaling Smooth Tomographic Models: Separating Intrinsic and Apparent Anisotropy

    NASA Astrophysics Data System (ADS)

    Bodin, Thomas; Capdeville, Yann; Romanowicz, Barbara

    2016-04-01

    In recent years, a number of tomographic models based on full waveform inversion have been published. Due to computational constraints, the fitted waveforms are low pass filtered, which results in an inability to map features smaller than half the shortest wavelength. However, these tomographic images are not a simple spatial average of the true model, but rather an effective, apparent, or equivalent model that provides a similar 'long-wave' data fit. For example, it can be shown that a series of horizontal isotropic layers will be seen by a 'long wave' as a smooth anisotropic medium. In this way, the observed anisotropy in tomographic models is a combination of intrinsic anisotropy produced by lattice-preferred orientation (LPO) of minerals, and apparent anisotropy resulting from the incapacity of mapping discontinuities. Interpretations of observed anisotropy (e.g. in terms of mantle flow) requires therefore the separation of its intrinsic and apparent components. The "up-scaling" relations that link elastic properties of a rapidly varying medium to elastic properties of the effective medium as seen by long waves are strongly non-linear and their inverse highly non-unique. That is, a smooth homogenized effective model is equivalent to a large number of models with discontinuities. In the 1D case, Capdeville et al (GJI, 2013) recently showed that a tomographic model which results from the inversion of low pass filtered waveforms is an homogenized model, i.e. the same as the model computed by upscaling the true model. Here we propose a stochastic method to sample the ensemble of layered models equivalent to a given tomographic profile. We use a transdimensional formulation where the number of layers is variable. Furthermore, each layer may be either isotropic (1 parameter) or intrinsically anisotropic (2 parameters). The parsimonious character of the Bayesian inversion gives preference to models with the least number of parameters (i.e. least number of layers, and

  14. Algebraic filter approach for fast approximation of nonlinear tomographic reconstruction methods

    NASA Astrophysics Data System (ADS)

    Plantagie, Linda; Batenburg, Kees Joost

    2015-01-01

    We present a computational approach for fast approximation of nonlinear tomographic reconstruction methods by filtered backprojection (FBP) methods. Algebraic reconstruction algorithms are the methods of choice in a wide range of tomographic applications, yet they require significant computation time, restricting their usefulness. We build upon recent work on the approximation of linear algebraic reconstruction methods and extend the approach to the approximation of nonlinear reconstruction methods which are common in practice. We demonstrate that if a blueprint image is available that is sufficiently similar to the scanned object, our approach can compute reconstructions that approximate iterative nonlinear methods, yet have the same speed as FBP.

  15. Research in applied mathematics, numerical analysis, and computer science

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Research conducted at the Institute for Computer Applications in Science and Engineering (ICASE) in applied mathematics, numerical analysis, and computer science is summarized and abstracts of published reports are presented. The major categories of the ICASE research program are: (1) numerical methods, with particular emphasis on the development and analysis of basic numerical algorithms; (2) control and parameter identification; (3) computational problems in engineering and the physical sciences, particularly fluid dynamics, acoustics, and structural analysis; and (4) computer systems and software, especially vector and parallel computers.

  16. A preliminary design study for improving performance in tomographic assays

    SciTech Connect

    Estep, R.J.

    1994-03-01

    The authors recently introduced the tomographic-gamma-scanner (TGS) method for assaying transuranic (TRU) waste and special nuclear material (SNM) in 55-gal drums. The TGS combines low-resolution emission and transmission tomography to obtain attenuation-corrected images of the radionuclide distribution inside a drum. In a low-resolution tomographic assay device, it is desirable to have as flat an efficiency profile as possible. Using computer simulations, they have demonstrated that a flat response in the vertical direction can be obtained by using a diamond-shaped collimator, and that this flatness of response translates into improved assay accuracy. Similarly, they have shown that the use of a continuous-motion scan protocol reduces horizontal efficiency variations.

  17. Computational method for analysis of polyethylene biodegradation

    NASA Astrophysics Data System (ADS)

    Watanabe, Masaji; Kawai, Fusako; Shibata, Masaru; Yokoyama, Shigeo; Sudate, Yasuhiro

    2003-12-01

    In a previous study concerning the biodegradation of polyethylene, we proposed a mathematical model based on two primary factors: the direct consumption or absorption of small molecules and the successive weight loss of large molecules due to β-oxidation. Our model is an initial value problem consisting of a differential equation whose independent variable is time. Its unknown variable represents the total weight of all the polyethylene molecules that belong to a molecular-weight class specified by a parameter. In this paper, we describe a numerical technique to introduce experimental results into analysis of our model. We first establish its mathematical foundation in order to guarantee its validity, by showing that the initial value problem associated with the differential equation has a unique solution. Our computational technique is based on a linear system of differential equations derived from the original problem. We introduce some numerical results to illustrate our technique as a practical application of the linear approximation. In particular, we show how to solve the inverse problem to determine the consumption rate and the β-oxidation rate numerically, and illustrate our numerical technique by analyzing the GPC patterns of polyethylene wax obtained before and after 5 weeks cultivation of a fungus, Aspergillus sp. AK-3. A numerical simulation based on these degradation rates confirms that the primary factors of the polyethylene biodegradation posed in modeling are indeed appropriate.

  18. Environmental studies: Mathematical, computational, and statistical analysis

    SciTech Connect

    Wheeler, M.F.

    1996-12-31

    The Summer Program on Mathematical, Computational, and Statistical Analyses in Environmental Studies held 6--31 July 1992 was designed to provide a much needed interdisciplinary forum for joint exploration of recent advances in the formulation and application of (A) environmental models, (B) environmental data and data assimilation, (C) stochastic modeling and optimization, and (D) global climate modeling. These four conceptual frameworks provided common themes among a broad spectrum of specific technical topics at this workshop. The program brought forth a mix of physical concepts and processes such as chemical kinetics, atmospheric dynamics, cloud physics and dynamics, flow in porous media, remote sensing, climate statistical, stochastic processes, parameter identification, model performance evaluation, aerosol physics and chemistry, and data sampling together with mathematical concepts in stiff differential systems, advective-diffusive-reactive PDEs, inverse scattering theory, time series analysis, particle dynamics, stochastic equations, optimal control, and others. Nineteen papers are presented in this volume. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  19. [Computational genome analysis of three marine algoviruses].

    PubMed

    Stepanova, O A; Boĭko, A L; Shcherbatenko, I S

    2013-01-01

    Computational analysis of genomic sequences of three new marine algoviruses: Tetraselmis viridis virus (TvV-S20 and TvV-SI1 strains) and Dunaliella viridis virus (DvV-SI2 strain) was conducted. Both considerable similarity and essential distinctions between studied strains and the most studied marine algoviruses of Phycodnaviridae family were revealed. Our data show that the tested strains are new viruses with the following features: only they were isolated from marine eukaryotic microalgae T. viridis and D. viridis, coding sequences (CDSs) of their genomes are localized mainly on one of the DNA strands and form several clusters with short intergenic spaces; there are considerable variations in genome structure within viruses and their strains; viral genomic DNA has a high GC-content (55.5 - 67.4%); their genes contain no well-known optimal contexts of translation start codones, and the contexts of terminal codons read-through; the vast majority of viral genes and proteins do not have any matches in gene banks. PMID:24479317

  20. Computer-aided petrographic analysis of sandstones

    SciTech Connect

    Thayer, P.A.; Helmold, K.P.

    1987-05-01

    Thin-section point counting, mathematical and statistical analysis of petrographic-petrophysical data, report generation, and graphical presentation of results can be done efficiently by computer. Compositional and textural data are collected with a modified Schares point-counting system. The system uses an MS-DOS microcomputer programmed in BASIC to drive a motorized stage attached to a polarizing microscope. Numeric codes for up to 500 different categories of minerals, cements, pores, etc, are input using a separate keypad. Calculation and printing of constituent percentages, QFR, Folk name, and grain-size distribution are completed in seconds after data entry. Raw data files, compatible with software such as Lotus 1-2-3, SPSS, and SAS, are stored on floppy disk. Petrographic data files are transferred directly to a mainframe, merged with log and petrophysical data, analyzed statistically with SAS, and reports generated. SAS/GRAPH and TELL-A-GRAF routines linked with SAS generate a variety of cross plots, histograms, pie and bar charts, ternary diagrams, and vertical variation diagrams (e.g., depth vs. porosity, permeability, mean size, sorting, and percent grains-matrix-cement).

  1. Hydrodynamic Simulations and Tomographic Reconstructions of the Intergalactic Medium

    NASA Astrophysics Data System (ADS)

    Stark, Casey William

    The Intergalactic Medium (IGM) is the dominant reservoir of matter in the Universe from which the cosmic web and galaxies form. The structure and physical state of the IGM provides insight into the cosmological model of the Universe, the origin and timeline of the reionization of the Universe, as well as being an essential ingredient in our understanding of galaxy formation and evolution. Our primary handle on this information is a signal known as the Lyman-alpha forest (or Ly-alpha forest) -- the collection of absorption features in high-redshift sources due to intervening neutral hydrogen, which scatters HI Ly-alpha photons out of the line of sight. The Ly-alpha forest flux traces density fluctuations at high redshift and at moderate overdensities, making it an excellent tool for mapping large-scale structure and constraining cosmological parameters. Although the computational methodology for simulating the Ly-alpha forest has existed for over a decade, we are just now approaching the scale of computing power required to simultaneously capture large cosmological scales and the scales of the smallest absorption systems. My thesis focuses on using simulations at the edge of modern computing to produce precise predictions of the statistics of the Ly-alpha forest and to better understand the structure of the IGM. In the first part of my thesis, I review the state of hydrodynamic simulations of the IGM, including pitfalls of the existing under-resolved simulations. Our group developed a new cosmological hydrodynamics code to tackle the computational challenge, and I developed a distributed analysis framework to compute flux statistics from our simulations. I present flux statistics derived from a suite of our large hydrodynamic simulations and demonstrate convergence to the per cent level. I also compare flux statistics derived from simulations using different discretizations and hydrodynamic schemes (Eulerian finite volume vs. smoothed particle hydrodynamics) and

  2. Parallel Analysis and Visualization on Cray Compute Node Linux

    SciTech Connect

    Pugmire, Dave; Ahern, Sean

    2008-01-01

    Capability computer systems are deployed to give researchers the computational power required to investigate and solve key challenges facing the scientific community. As the power of these computer systems increases, the computational problem domain typically increases in size, complexity and scope. These increases strain the ability of commodity analysis and visualization clusters to effectively perform post-processing tasks and provide critical insight and understanding to the computed results. An alternative to purchasing increasingly larger, separate analysis and visualization commodity clusters is to use the computational system itself to perform post-processing tasks. In this paper, the recent successful port of VisIt, a parallel, open source analysis and visualization tool, to compute node linux running on the Cray is detailed. Additionally, the unprecedented ability of this resource for analysis and visualization is discussed and a report on obtained results is presented.

  3. Information fusion in regularized inversion of tomographic pumping tests

    USGS Publications Warehouse

    Bohling, G.C.

    2008-01-01

    In this chapter we investigate a simple approach to incorporating geophysical information into the analysis of tomographic pumping tests for characterization of the hydraulic conductivity (K) field in an aquifer. A number of authors have suggested a tomographic approach to the analysis of hydraulic tests in aquifers - essentially simultaneous analysis of multiple tests or stresses on the flow system - in order to improve the resolution of the estimated parameter fields. However, even with a large amount of hydraulic data in hand, the inverse problem is still plagued by non-uniqueness and ill-conditioning and the parameter space for the inversion needs to be constrained in some sensible fashion in order to obtain plausible estimates of aquifer properties. For seismic and radar tomography problems, the parameter space is often constrained through the application of regularization terms that impose penalties on deviations of the estimated parameters from a prior or background model, with the tradeoff between data fit and model norm explored through systematic analysis of results for different levels of weighting on the regularization terms. In this study we apply systematic regularized inversion to analysis of tomographic pumping tests in an alluvial aquifer, taking advantage of the steady-shape flow regime exhibited in these tests to expedite the inversion process. In addition, we explore the possibility of incorporating geophysical information into the inversion through a regularization term relating the estimated K distribution to ground penetrating radar velocity and attenuation distributions through a smoothing spline model. ?? 2008 Springer-Verlag Berlin Heidelberg.

  4. New computing systems, future computing environment, and their implications on structural analysis and design

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.; Housner, Jerrold M.

    1993-01-01

    Recent advances in computer technology that are likely to impact structural analysis and design of flight vehicles are reviewed. A brief summary is given of the advances in microelectronics, networking technologies, and in the user-interface hardware and software. The major features of new and projected computing systems, including high performance computers, parallel processing machines, and small systems, are described. Advances in programming environments, numerical algorithms, and computational strategies for new computing systems are reviewed. The impact of the advances in computer technology on structural analysis and the design of flight vehicles is described. A scenario for future computing paradigms is presented, and the near-term needs in the computational structures area are outlined.

  5. Volume accumulator design analysis computer codes

    NASA Technical Reports Server (NTRS)

    Whitaker, W. D.; Shimazaki, T. T.

    1973-01-01

    The computer codes, VANEP and VANES, were written and used to aid in the design and performance calculation of the volume accumulator units (VAU) for the 5-kwe reactor thermoelectric system. VANEP computes the VAU design which meets the primary coolant loop VAU volume and pressure performance requirements. VANES computes the performance of the VAU design, determined from the VANEP code, at the conditions of the secondary coolant loop. The codes can also compute the performance characteristics of the VAU's under conditions of possible modes of failure which still permit continued system operation.

  6. Evaluation of a Multicore-Optimized Implementation for Tomographic Reconstruction

    PubMed Central

    Agulleiro, Jose-Ignacio; Fernández, José Jesús

    2012-01-01

    Tomography allows elucidation of the three-dimensional structure of an object from a set of projection images. In life sciences, electron microscope tomography is providing invaluable information about the cell structure at a resolution of a few nanometres. Here, large images are required to combine wide fields of view with high resolution requirements. The computational complexity of the algorithms along with the large image size then turns tomographic reconstruction into a computationally demanding problem. Traditionally, high-performance computing techniques have been applied to cope with such demands on supercomputers, distributed systems and computer clusters. In the last few years, the trend has turned towards graphics processing units (GPUs). Here we present a detailed description and a thorough evaluation of an alternative approach that relies on exploitation of the power available in modern multicore computers. The combination of single-core code optimization, vector processing, multithreading and efficient disk I/O operations succeeds in providing fast tomographic reconstructions on standard computers. The approach turns out to be competitive with the fastest GPU-based solutions thus far. PMID:23139768

  7. NASA Applications for Computational Electromagnetic Analysis

    NASA Technical Reports Server (NTRS)

    Lewis, Catherine C.; Trout, Dawn H.; Krome, Mark E.; Perry, Thomas A.

    2011-01-01

    Computational Electromagnetic Software is used by NASA to analyze the compatibility of systems too large or too complex for testing. Recent advances in software packages and computer capabilities have made it possible to determine the effects of a transmitter inside a launch vehicle fairing, better analyze the environment threats, and perform on-orbit replacements with assured electromagnetic compatibility.

  8. An Analysis of 27 Years of Research into Computer Education Published in Australian Educational Computing

    ERIC Educational Resources Information Center

    Zagami, Jason

    2015-01-01

    Analysis of three decades of publications in Australian Educational Computing (AEC) provides insight into the historical trends in Australian educational computing, highlighting an emphasis on pedagogy, comparatively few articles on educational technologies, and strong research topic alignment with similar international journals. Analysis confirms…

  9. Transonic wing analysis using advanced computational methods

    NASA Technical Reports Server (NTRS)

    Henne, P. A.; Hicks, R. M.

    1978-01-01

    This paper discusses the application of three-dimensional computational transonic flow methods to several different types of transport wing designs. The purpose of these applications is to evaluate the basic accuracy and limitations associated with such numerical methods. The use of such computational methods for practical engineering problems can only be justified after favorable evaluations are completed. The paper summarizes a study of both the small-disturbance and the full potential technique for computing three-dimensional transonic flows. Computed three-dimensional results are compared to both experimental measurements and theoretical results. Comparisons are made not only of pressure distributions but also of lift and drag forces. Transonic drag rise characteristics are compared. Three-dimensional pressure distributions and aerodynamic forces, computed from the full potential solution, compare reasonably well with experimental results for a wide range of configurations and flow conditions.

  10. Frequency Analysis Program for a Computer Assisted Laboratory.

    ERIC Educational Resources Information Center

    Aburdene, Maurice F.

    1983-01-01

    Describes a Fortran program used in a computer-assisted-laboratory course. Program utilizes computer-controlled frequency sweeping to measure response (amplitude/phase) of a series RLC circuit, modeling the circuit and comparing experimental/theoretical results for system gain with computer gain using least squares analysis. Plots of both gain…

  11. Numerical Package in Computer Supported Numeric Analysis Teaching

    ERIC Educational Resources Information Center

    Tezer, Murat

    2007-01-01

    At universities in the faculties of Engineering, Sciences, Business and Economics together with higher education in Computing, it is stated that because of the difficulty, calculators and computers can be used in Numerical Analysis (NA). In this study, the learning computer supported NA will be discussed together with important usage of the…

  12. High resolution tomographic instrument development

    SciTech Connect

    Not Available

    1992-08-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  13. High resolution tomographic instrument development

    SciTech Connect

    Not Available

    1992-01-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  14. High resolution tomographic instrument development

    NASA Astrophysics Data System (ADS)

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefitted greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  15. Alternative Computational Approaches for Probalistic Fatigue Analysis

    NASA Technical Reports Server (NTRS)

    Ebbeler, D. H.; Newlin, L. E.; Sutharshana, S.; Moore, N. R.; Grigoriu, M.

    1995-01-01

    The feasibility is discussed for alternative methods of direct Monte Carlo simulation for failure probability computations. First and second order reliability methods are used for fatigue crack growth and low cycle fatigue structural failure modes to illustrate typical problems.

  16. System balance analysis for vector computers

    NASA Technical Reports Server (NTRS)

    Knight, J. C.; Poole, W. G., Jr.; Voight, R. G.

    1975-01-01

    The availability of vector processors capable of sustaining computing rates of 10 to the 8th power arithmetic results pers second raised the question of whether peripheral storage devices representing current technology can keep such processors supplied with data. By examining the solution of a large banded linear system on these computers, it was found that even under ideal conditions, the processors will frequently be waiting for problem data.

  17. Tomographic Adaptive Optics and Turbulence Profiling

    NASA Astrophysics Data System (ADS)

    Morris, Tim

    2015-04-01

    The use of tomographic adaptive optics is fundamental to fulfilling scientific goals for many proposed instruments at major observatories. Tomographic AO uses knowledge of the atmospheric C2n profile and to date, the majority of the profiles used to design and simulate these systems have come from external turbulence profilers. The C2n profile resolution required for accurate predictions of ELT instrumentation exceeds that of existing instrumentation and here we define the requirements on these profilers for ELT support. However, tomographic AO systems can also measure C2n profiles and we highlight several cases where external profilers can provide critical functionality to support on-sky operations.

  18. Spin scan tomographic array-based imager.

    PubMed

    Hovland, Harald

    2014-12-29

    This work presents a novel imaging device based on tomographic reconstruction. Similar in certain aspects to the earlier presented tomographic scanning (TOSCA) principle, it provides several important enhancements. The device described generates a stream of one-dimensional projections from a linear array of thin stripe detectors onto which the (circular) image of the scene is rotated. A two-dimensional image is then reproduced from the one-dimensional signals using tomographic processing techniques. A demonstrator is presented. Various aspects of the design and construction are discussed, and resulting images and movies are presented. PMID:25607168

  19. Three parallel computation methods for structural vibration analysis

    NASA Technical Reports Server (NTRS)

    Storaasli, Olaf; Bostic, Susan; Patrick, Merrell; Mahajan, Umesh; Ma, Shing

    1988-01-01

    The Lanczos (1950), multisectioning, and subspace iteration sequential methods for vibration analysis presently used as bases for three parallel algorithms are noted, in the aftermath of three example problems, to maintain reasonable accuracy in the computation of vibration frequencies. Significant computation time reductions are obtained as the number of processors increases. An analysis is made of the performance of each method, in order to characterize relative strengths and weaknesses as well as to identify those parameters that most strongly affect computation efficiency.

  20. Multimodality tomographic scintimammography with PET, PECI, and SPECT: initial evaluation

    NASA Astrophysics Data System (ADS)

    Krol, Andrzej; Feiglin, David H.; Thomas, Frank D.; Hellwig, Bradford J.; Gagne, George M.

    2002-04-01

    We compared tomographic scintimammography performed using single photon emission computed tomography (SPECT), positron emission coincidence imaging (PECI) and positron emission tomography (PET). A female thorax phantom was used. Activities of the myocardium, thorax and breasts were adjusted to emulate the count rate observed with patients. Hollow plastic spheres, imitating hot lesions (1.5-20ml), filled with radioactive saline were inserted in the center of each breast. Specific activities of internal organs were adjusted to emulate the count rate observed with patients. SPECT data were acquired with Tc-99m using gamma cameras with NaI(Tl) detectors. A modified FBP (CODE) reconstruction algorithm was used to render SPECT tomographic images. PECI (Siemens E.CAM with NaI(Tl)) and PET (GE Advance with BGO) data were acquired using F-18 FDG. Vendor supplied reconstruction algorithms were used. The reconstructed hot lesions contrast and resolution were investigated. Image quality obtained can be ranked as follows: (1) PET(BGO), (2) PECI(NaI), (3) SPECT(NaI) In conclusion, assuming comparable uptake values of Tc-99m-sestamibi and F-18 FDG, PET seems to be a superior methodology in visualization of breast lesion as compared to SPECT and PECI. All these tomographic methods appear to be promising adjunct to x-ray mammography in difficult to interpret cases.

  1. Scanning tomographic acoustic microscopy: principles and recent developments (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Wade, G.; Meyyappan, A.

    1987-09-01

    Acoustic Microscopy is an important branch of non-destructive evaluation which provides high resolution for imaging the detailed structure of a small object. When an acoustic microscope operates in the transmission mode, the micrograph is simply a shadowgraph of all the structures encountered by the acoustic wave passing through the object. Because of diffraction and overlapping, the resultant images are difficult to comprehend in the case of specimens of substantial thickness and structural complexity. We used the principles of diffraction tomography and acoustical holography along with digital calcuations of wavefield propagation to overcome this problem. We have described in previously-published work how a scanning laser acoustic microscope (SLAM) can be modified to obtain data for subsurface tomographic imaging. In this paper, we review the principles of scanning tomographic acoustic microscopy (STAM). The required modification of SLAM to obtain STAM and the reconstruction process are described. We show how we are able to accurately acquire the complex-amplitude information necessary for image reconstruction. We demonstrate the power of this technique by comparing digitally-computed images thus obtained with analogue images of a conventional SLAM. The results show that high-quality, high-resolution subsurface images can be obtained from experimentally acquired data. We also describe techniques to obtain projection data from different angles of wave incidence enabling us to tomographically reconstruct different planes of a complex specimen in microscopic detail. With these modifications in place, STAM should shortly become a powerful tool in non-destructive evaluation.

  2. Computational analysis of LDDMM for brain mapping

    PubMed Central

    Ceritoglu, Can; Tang, Xiaoying; Chow, Margaret; Hadjiabadi, Darian; Shah, Damish; Brown, Timothy; Burhanullah, Muhammad H.; Trinh, Huong; Hsu, John T.; Ament, Katarina A.; Crocetti, Deana; Mori, Susumu; Mostofsky, Stewart H.; Yantis, Steven; Miller, Michael I.; Ratnanather, J. Tilak

    2013-01-01

    One goal of computational anatomy (CA) is to develop tools to accurately segment brain structures in healthy and diseased subjects. In this paper, we examine the performance and complexity of such segmentation in the framework of the large deformation diffeomorphic metric mapping (LDDMM) registration method with reference to atlases and parameters. First we report the application of a multi-atlas segmentation approach to define basal ganglia structures in healthy and diseased kids' brains. The segmentation accuracy of the multi-atlas approach is compared with the single atlas LDDMM implementation and two state-of-the-art segmentation algorithms—Freesurfer and FSL—by computing the overlap errors between automatic and manual segmentations of the six basal ganglia nuclei in healthy subjects as well as subjects with diseases including ADHD and Autism. The high accuracy of multi-atlas segmentation is obtained at the cost of increasing the computational complexity because of the calculations necessary between the atlases and a subject. Second, we examine the effect of parameters on total LDDMM computation time and segmentation accuracy for basal ganglia structures. Single atlas LDDMM method is used to automatically segment the structures in a population of 16 subjects using different sets of parameters. The results show that a cascade approach and using fewer time steps can reduce computational complexity as much as five times while maintaining reliable segmentations. PMID:23986653

  3. Novel Ultrasound Tomograph for Anatomical Inspection

    NASA Astrophysics Data System (ADS)

    Rouyer, Julien; Lasaygues, Philippe; Mensah, Serge

    A device for ultrasound computed tomography (UCT) is introduced here. An half-ring transducer array was designed in conformity with the breast anatomy and the cancer growth region to perform an early detection. The array comprises 1,024 elements set in a 190-degree circular arc with a radius of 100 mm. The nominal frequency is 3 MHz with a 79% -6 dB bandwidth. The front-end electronics incorporate 32 independent transmit/receive parallel channels and a 32-to-1,024 multiplexer unit. The acquisition circuitries have a variable sampling frequency of up to 80 MHz and a precision of 12 bits. Arbitrary waveforms are synthesized to improve the signal-to-noise ratio and to increase the in-depth resolution. Tomographic acquisitions were realized in diffraction mode using a restricted aperture. The backscattered field was recorded in the case of a string phantom (0.08-mm diameter steel threads) and a breast-shaped phantom containing inclusions. Data were processed with dedicated correction tools processes such as pulse compression. Objects were reconstructed with the ellipsoidal back-projection method.

  4. Modern Computational Techniques for the HMMER Sequence Analysis

    PubMed Central

    2013-01-01

    This paper focuses on the latest research and critical reviews on modern computing architectures, software and hardware accelerated algorithms for bioinformatics data analysis with an emphasis on one of the most important sequence analysis applications—hidden Markov models (HMM). We show the detailed performance comparison of sequence analysis tools on various computing platforms recently developed in the bioinformatics society. The characteristics of the sequence analysis, such as data and compute-intensive natures, make it very attractive to optimize and parallelize by using both traditional software approach and innovated hardware acceleration technologies. PMID:25937944

  5. Global detailed geoid computation and model analysis

    NASA Technical Reports Server (NTRS)

    Marsh, J. G.; Vincent, S.

    1974-01-01

    Comparisons and analyses were carried out through the use of detailed gravimetric geoids which we have computed by combining models with a set of 26,000 1 deg x 1 deg mean free air gravity anomalies. The accuracy of the detailed gravimetric geoid computed using the most recent Goddard earth model (GEM-6) in conjunction with the set of 1 deg x 1 deg mean free air gravity anomalies is assessed at + or - 2 meters on the continents of North America, Europe, and Australia, 2 to 5 meters in the Northeast Pacific and North Atlantic areas, and 5 to 10 meters in other areas where surface gravity data are sparse. The R.M.S. differences between this detailed geoid and the detailed geoids computed using the other satellite gravity fields in conjuction with same set of surface data range from 3 to 7 meters.

  6. Hypercube-Computer Analysis Of Electromagnetic Scattering

    NASA Technical Reports Server (NTRS)

    Patterson, J. E.; Liewer, P. C.; Calalo, R. H.; Manshadi, F.

    1990-01-01

    Capabilities of hypercube and parallel processing demonstrated. Report describes use of Mark III Hypercube computer to analyze scattering of electromagnetic waves. Purpose of study to assess utility of parallel computing in such computation-intensive problems as large-scale electromagnetic scattering. Two electromagnetic codes based on different algorithms converted to run on Mark III Hypercube. First code implements finite-difference, time-domain solution of Maxwell's curl equations. Second code is Numerical Electromagnetics Code (NEC-2) which embodies frequency-domain method and developed to analyze electromagnetic responses of antennas and other metallic structures. On Mark III Hypercube with 32 active nodes, largest lattice contains about 2,048,000 unit cells.

  7. Computational Analysis of SAXS Data Acquisition.

    PubMed

    Dong, Hui; Kim, Jin Seob; Chirikjian, Gregory S

    2015-09-01

    Small-angle x-ray scattering (SAXS) is an experimental biophysical method used for gaining insight into the structure of large biomolecular complexes. Under appropriate chemical conditions, the information obtained from a SAXS experiment can be equated to the pair distribution function, which is the distribution of distances between every pair of points in the complex. Here we develop a mathematical model to calculate the pair distribution function for a structure of known density, and analyze the computational complexity of these calculations. Efficient recursive computation of this forward model is an important step in solving the inverse problem of recovering the three-dimensional density of biomolecular structures from their pair distribution functions. In particular, we show that integrals of products of three spherical-Bessel functions arise naturally in this context. We then develop an algorithm for the efficient recursive computation of these integrals. PMID:26244255

  8. Efficacy of Mucograft vs Conventional Resorbable Collagen Membranes in Guided Bone Regeneration Around Standardized Calvarial Defects in Rats: An In Vivo Microcomputed Tomographic Analysis.

    PubMed

    Babay, Nadir; Ramalingam, Sundar; Basudan, Amani; Nooh, Nasser; AlKindi, Mohammed; Al-Rasheed, Abdulaziz; Al-Hezaimi, Khalid

    2016-01-01

    The aim of this in vivo microcomputed tomographic (μCT) study was to compare the efficacy of Mucograft (MG) vs resorbable collagen membranes (RCMs) in facilitating guided bone regeneration (GBR) around standardized calvarial defects in rats. Forty female Wistar albino rats with a mean age and weight of 6 to 9 weeks and 250 to 300 g, respectively, were used. With the rats under general anesthesia, the skin over the calvaria was exposed using a full-thickness flap. A standardized calvarial defect with a 4.6-mm diameter was created in the left parietal bone. For treatment, the rats were randomly divided into four groups (n = 10 per group): (1) defects covered with MG (MG group); (2) defects covered with an RCM (RCM group); (3) defects filled with xenograft bone particles and covered by MG (MG + bone group); and (4) defects filled with xenograft bone particles and covered by an RCM (RCM + bone group). Primary closure was achieved using interrupted resorbable sutures. The animals underwent high-resolution, three-dimensional μCT scans at baseline and at 2, 4, 6, and 8 weeks after the surgical procedures. Data regarding volume and bone mineral density (BMD) of newly formed bone (NFB) and bone particles revealed an increase in the volume of NFB in all the groups from baseline to 8 weeks. The MG group had the lowest volume of NFB (mean ± standard deviation [SD], 1.32 ± 0.22 mm(3)). No significant differences in mean ± SD values for volume of NFB were observed between the RCM (3.50 ± 0.24 mm(3)) and MG + bone (3.87 ± 0.36 mm(3)) groups, but their values were significantly lower than that of the RCM + bone group (2.95 ± 0.15 mm(3), F = 131.91, dfN = 2, dfD = 27, P < .001). Significant differences in BMD of NFB between the groups (F = 332.46, dfN = 3, dfD = 36, P < .001) and during different data collection periods (F = 97.04, dfN = 3, dfD = 36, P < .01) were observed, with the RCM group having the highest mean ± SD BMD of NFB (0.42 ± 0.05 g/mm(3)). Significant

  9. Tomographic phase microscopy using optical tweezers

    NASA Astrophysics Data System (ADS)

    Habaza, Mor; Gilboa, Barak; Roichman, Yael; Shaked, Natan T.

    2015-07-01

    We review our technique for tomographic phase microscopy with optical tweezers [1]. This tomographic phase microscopy approach enables full 3-D refractive-index reconstruction. Tomographic phase microscopy measures quantitatively the 3- D distribution of refractive-index in biological cells. We integrated our external interferometric module with holographic optical tweezers for obtaining quantitative phase maps of biological samples from a wide range of angles. The close-tocommon- path, off-axis interferometric system enables a full-rotation tomographic acquisition of a single cell using holographic optical tweezers for trapping and manipulating with a desired array of traps, while acquiring phase information of a single cell from all different angles and maintaining the native surrounding medium. We experimentally demonstrated two reconstruction algorithms: the filtered back-projection method and the Fourier diffraction method for 3-D refractive index imaging of yeast cells.

  10. An emulator for minimizing computer resources for finite element analysis

    NASA Technical Reports Server (NTRS)

    Melosh, R.; Utku, S.; Islam, M.; Salama, M.

    1984-01-01

    A computer code, SCOPE, has been developed for predicting the computer resources required for a given analysis code, computer hardware, and structural problem. The cost of running the code is a small fraction (about 3 percent) of the cost of performing the actual analysis. However, its accuracy in predicting the CPU and I/O resources depends intrinsically on the accuracy of calibration data that must be developed once for the computer hardware and the finite element analysis code of interest. Testing of the SCOPE code on the AMDAHL 470 V/8 computer and the ELAS finite element analysis program indicated small I/O errors (3.2 percent), larger CPU errors (17.8 percent), and negligible total errors (1.5 percent).

  11. Thermoelectric pump performance analysis computer code

    NASA Technical Reports Server (NTRS)

    Johnson, J. L.

    1973-01-01

    A computer program is presented that was used to analyze and design dual-throat electromagnetic dc conduction pumps for the 5-kwe ZrH reactor thermoelectric system. In addition to a listing of the code and corresponding identification of symbols, the bases for this analytical model are provided.

  12. Computer program performs stiffness matrix structural analysis

    NASA Technical Reports Server (NTRS)

    Bamford, R.; Batchelder, R.; Schmele, L.; Wada, B. K.

    1968-01-01

    Computer program generates the stiffness matrix for a particular type of structure from geometrical data, and performs static and normal mode analyses. It requires the structure to be modeled as a stable framework of uniform, weightless members, and joints at which loads are applied and weights are lumped.

  13. Computational and Physical Analysis of Catalytic Compounds

    NASA Astrophysics Data System (ADS)

    Wu, Richard; Sohn, Jung Jae; Kyung, Richard

    2015-03-01

    Nanoparticles exhibit unique physical and chemical properties depending on their geometrical properties. For this reason, synthesis of nanoparticles with controlled shape and size is important to use their unique properties. Catalyst supports are usually made of high-surface-area porous oxides or carbon nanomaterials. These support materials stabilize metal catalysts against sintering at high reaction temperatures. Many studies have demonstrated large enhancements of catalytic behavior due to the role of the oxide-metal interface. In this paper, the catalyzing ability of supported nano metal oxides, such as silicon oxide and titanium oxide compounds as catalysts have been analyzed using computational chemistry method. Computational programs such as Gamess and Chemcraft has been used in an effort to compute the efficiencies of catalytic compounds, and bonding energy changes during the optimization convergence. The result illustrates how the metal oxides stabilize and the steps that it takes. The graph of the energy computation step(N) versus energy(kcal/mol) curve shows that the energy of the titania converges faster at the 7th iteration calculation, whereas the silica converges at the 9th iteration calculation.

  14. Computed Tomography Analysis of NASA BSTRA Balls

    SciTech Connect

    Perry, R L; Schneberk, D J; Thompson, R R

    2004-10-12

    Fifteen 1.25 inch BSTRA balls were scanned with the high energy computed tomography system at LLNL. This system has a resolution limit of approximately 210 microns. A threshold of 238 microns (two voxels) was used, and no anomalies at or greater than this were observed.

  15. Reliability computation using fault tree analysis

    NASA Technical Reports Server (NTRS)

    Chelson, P. O.

    1971-01-01

    A method is presented for calculating event probabilities from an arbitrary fault tree. The method includes an analytical derivation of the system equation and is not a simulation program. The method can handle systems that incorporate standby redundancy and it uses conditional probabilities for computing fault trees where the same basic failure appears in more than one fault path.

  16. Wing analysis using a transonic potential flow computational method

    NASA Technical Reports Server (NTRS)

    Henne, P. A.; Hicks, R. M.

    1978-01-01

    The ability of the method to compute wing transonic performance was determined by comparing computed results with both experimental data and results computed by other theoretical procedures. Both pressure distributions and aerodynamic forces were evaluated. Comparisons indicated that the method is a significant improvement in transonic wing analysis capability. In particular, the computational method generally calculated the correct development of three-dimensional pressure distributions from subcritical to transonic conditions. Complicated, multiple shocked flows observed experimentally were reproduced computationally. The ability to identify the effects of design modifications was demonstrated both in terms of pressure distributions and shock drag characteristics.

  17. Tomographic thallium-201 myocardial perfusion scintigrams after maximal coronary artery vasodilation with intravenous dipyridamole: comparison of qualitative and quantitative approaches

    SciTech Connect

    Francisco, D.A.; Collins, S.M.; Go, R.T.; Ehrhardt, J.C.; Van Kirk, O.C.; Marcus, M.L.

    1982-08-01

    Eighty-six patients had thallium-201 (/sup 201/Tl) myocardial perfusion scintigrams after intense coronary artery dilation with i.v. dipyridamole. Tomographic and planar /sup 201/Tl scintigrams were obtained in each patient. Tomographic scintigrams were interpreted using quantitative or visual criteria; planar scintigrams were assessed using visual criteria only. When visual criteria were used, interobserver variability was 40% for tomographic scintigrams and 44% for planar scintigrams. In the 24 patients with normal or nonsignificant CAD, quantitative analysis of the tomograms (range approach) indicated that one of 24 (4%) had a positive image (specificity 96%%); in contrast, when visual criteria were used to interpret the tomographic or planar /sup 201/Tl scintigrams, eight of 24 (33%) had positive scintigrams (specificity 67%). In the 51 abnormal patients, the sensitivity of detecting CAD was 46 of 51 (90%) for tomographic scintigrams interpreted quantitatively, 39 of 51 (76%) for tomographic scintigrams interpreted visually and 41 of 51 (80%) for planar scintigrams assessed visually. The tomographic imaging procedure (quantitative interpretation) also demonstrated a high sensitivity (89%) and specificity (100%) in 28 patients (10 normal and 18 CAD), with a clinical diagnosis of unstable angina pectoris. Overall, the predictive accuracy of an abnormal scintigram with quantitative tomographic imaging (98%) was significantly better (p<0.05) than either qualitative planar or pinhole imaging. (JMT)

  18. Computational thermo-fluid analysis of a disk brake

    NASA Astrophysics Data System (ADS)

    Takizawa, Kenji; Tezduyar, Tayfun E.; Kuraishi, Takashi; Tabata, Shinichiro; Takagi, Hirokazu

    2016-06-01

    We present computational thermo-fluid analysis of a disk brake, including thermo-fluid analysis of the flow around the brake and heat conduction analysis of the disk. The computational challenges include proper representation of the small-scale thermo-fluid behavior, high-resolution representation of the thermo-fluid boundary layers near the spinning solid surfaces, and bringing the heat transfer coefficient (HTC) calculated in the thermo-fluid analysis of the flow to the heat conduction analysis of the spinning disk. The disk brake model used in the analysis closely represents the actual configuration, and this adds to the computational challenges. The components of the method we have developed for computational analysis of the class of problems with these types of challenges include the Space-Time Variational Multiscale method for coupled incompressible flow and thermal transport, ST Slip Interface method for high-resolution representation of the thermo-fluid boundary layers near spinning solid surfaces, and a set of projection methods for different parts of the disk to bring the HTC calculated in the thermo-fluid analysis. With the HTC coming from the thermo-fluid analysis of the flow around the brake, we do the heat conduction analysis of the disk, from the start of the breaking until the disk spinning stops, demonstrating how the method developed works in computational analysis of this complex and challenging problem.

  19. A maximum entropy reconstruction technique for tomographic particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Bilsky, A. V.; Lozhkin, V. A.; Markovich, D. M.; Tokarev, M. P.

    2013-04-01

    This paper studies a novel approach for reducing tomographic PIV computational complexity. The proposed approach is an algebraic reconstruction technique, termed MENT (maximum entropy). This technique computes the three-dimensional light intensity distribution several times faster than SMART, using at least ten times less memory. Additionally, the reconstruction quality remains nearly the same as with SMART. This paper presents the theoretical computation performance comparison for MENT, SMART and MART, followed by validation using synthetic particle images. Both the theoretical assessment and validation of synthetic images demonstrate significant computational time reduction. The data processing accuracy of MENT was compared to that of SMART in a slot jet experiment. A comparison of the average velocity profiles shows a high level of agreement between the results obtained with MENT and those obtained with SMART.

  20. Computer aided radiation analysis for manned spacecraft

    NASA Technical Reports Server (NTRS)

    Appleby, Matthew H.; Griffin, Brand N.; Tanner, Ernest R., II; Pogue, William R.; Golightly, Michael J.

    1991-01-01

    In order to assist in the design of radiation shielding an analytical tool is presented that can be employed in combination with CAD facilities and NASA transport codes. The nature of radiation in space is described, and the operational requirements for protection are listed as background information for the use of the technique. The method is based on the Boeing radiation exposure model (BREM) for combining NASA radiation transport codes and CAD facilities, and the output is given as contour maps of the radiation-shield distribution so that dangerous areas can be identified. Computational models are used to solve the 1D Boltzmann transport equation and determine the shielding needs for the worst-case scenario. BREM can be employed directly with the radiation computations to assess radiation protection during all phases of design which saves time and ultimately spacecraft weight.

  1. Hybrid soft computing systems for electromyographic signals analysis: a review

    PubMed Central

    2014-01-01

    Electromyographic (EMG) is a bio-signal collected on human skeletal muscle. Analysis of EMG signals has been widely used to detect human movement intent, control various human-machine interfaces, diagnose neuromuscular diseases, and model neuromusculoskeletal system. With the advances of artificial intelligence and soft computing, many sophisticated techniques have been proposed for such purpose. Hybrid soft computing system (HSCS), the integration of these different techniques, aims to further improve the effectiveness, efficiency, and accuracy of EMG analysis. This paper reviews and compares key combinations of neural network, support vector machine, fuzzy logic, evolutionary computing, and swarm intelligence for EMG analysis. Our suggestions on the possible future development of HSCS in EMG analysis are also given in terms of basic soft computing techniques, further combination of these techniques, and their other applications in EMG analysis. PMID:24490979

  2. Computer applications for engineering/structural analysis. Revision 1

    SciTech Connect

    Zaslawsky, M.; Samaddar, S.K.

    1991-12-31

    Analysts and organizations have a tendency to lock themselves into specific codes with the obvious consequences of not addressing the real problem and thus reaching the wrong conclusion. This paper discusses the role of the analyst in selecting computer codes. The participation and support of a computation division in modifying the source program, configuration management, and pre- and post-processing of codes are among the subjects discussed. Specific examples illustrating the computer code selection process are described in the following problem areas: soil structure interaction, structural analysis of nuclear reactors, analysis of waste tanks where fluid structure interaction is important, analysis of equipment, structure-structure interaction, analysis of the operation of the superconductor supercollider which includes friction and transient temperature, and 3D analysis of the 10-meter telescope being built in Hawaii. Validation and verification of computer codes and their impact on the selection process are also discussed.

  3. Advances in Computer-Based Autoantibodies Analysis

    NASA Astrophysics Data System (ADS)

    Soda, Paolo; Iannello, Giulio

    Indirect Immunofluorescence (IIF) imaging is the recommended me-thod to detect autoantibodies in patient serum, whose common markers are antinuclear autoantibodies (ANA) and autoantibodies directed against double strand DNA (anti-dsDNA). Since the availability of accurately performed and correctly reported laboratory determinations is crucial for the clinicians, an evident medical demand is the development of Computer Aided Diagnosis (CAD) tools supporting physicians' decisions.

  4. TAIR: A transonic airfoil analysis computer code

    NASA Technical Reports Server (NTRS)

    Dougherty, F. C.; Holst, T. L.; Grundy, K. L.; Thomas, S. D.

    1981-01-01

    The operation of the TAIR (Transonic AIRfoil) computer code, which uses a fast, fully implicit algorithm to solve the conservative full-potential equation for transonic flow fields about arbitrary airfoils, is described on two levels of sophistication: simplified operation and detailed operation. The program organization and theory are elaborated to simplify modification of TAIR for new applications. Examples with input and output are given for a wide range of cases, including incompressible, subcritical compressible, and transonic calculations.

  5. Scalable Computer Performance and Analysis (Hierarchical INTegration)

    Energy Science and Technology Software Center (ESTSC)

    1999-09-02

    HINT is a program to measure a wide variety of scalable computer systems. It is capable of demonstrating the benefits of using more memory or processing power, and of improving communications within the system. HINT can be used for measurement of an existing system, while the associated program ANALYTIC HINT can be used to explain the measurements or as a design tool for proposed systems.

  6. Lifetime-based tomographic multiplexing

    NASA Astrophysics Data System (ADS)

    Raymond, Scott B.; Boas, David A.; Bacskai, Brian J.; Kumar, Anand T. N.

    2010-07-01

    Near-infrared (NIR) fluorescence tomography of multiple fluorophores has previously been limited by the bandwidth of the NIR spectral regime and the broad emission spectra of most NIR fluorophores. We describe in vivo tomography of three spectrally overlapping fluorophores using fluorescence lifetime-based separation. Time-domain images are acquired using a voltage-gated, intensified charge-coupled device (CCD) in free-space transmission geometry with 750 nm Ti:sapphire laser excitation. Lifetime components are fit from the asymptotic portion of fluorescence decay curve and reconstructed separately with a lifetime-adjusted forward model. We use this system to test the in vivo lifetime multiplexing suitability of commercially available fluorophores, and demonstrate lifetime multiplexing in solution mixtures and in nude mice. All of the fluorophores tested exhibit nearly monoexponential decays, with narrow in vivo lifetime distributions suitable for lifetime multiplexing. Quantitative separation of two fluorophores with lifetimes of 1.1 and 1.37 ns is demonstrated for relative concentrations of 1:5. Finally, we demonstrate tomographic imaging of two and three fluorophores in nude mice with fluorophores that localize to distinct organ systems. This technique should be widely applicable to imaging multiple NIR fluorophores in 3-D.

  7. Tomographic PIV: particles versus blobs

    NASA Astrophysics Data System (ADS)

    Champagnat, Frédéric; Cornic, Philippe; Cheminet, Adam; Leclaire, Benjamin; Le Besnerais, Guy; Plyer, Aurélien

    2014-08-01

    We present an alternative approach to tomographic particle image velocimetry (tomo-PIV) that seeks to recover nearly single voxel particles rather than blobs of extended size. The baseline of our approach is a particle-based representation of image data. An appropriate discretization of this representation yields an original linear forward model with a weight matrix built with specific samples of the system’s point spread function (PSF). Such an approach requires only a few voxels to explain the image appearance, therefore it favors much more sparsely reconstructed volumes than classic tomo-PIV. The proposed forward model is general and flexible and can be embedded in a classical multiplicative algebraic reconstruction technique (MART) or a simultaneous multiplicative algebraic reconstruction technique (SMART) inversion procedure. We show, using synthetic PIV images and by way of a large exploration of the generating conditions and a variety of performance metrics, that the model leads to better results than the classical tomo-PIV approach, in particular in the case of seeding densities greater than 0.06 particles per pixel and of PSFs characterized by a standard deviation larger than 0.8 pixels.

  8. A PC-controlled microwave tomographic scanner for breast imaging

    NASA Astrophysics Data System (ADS)

    Padhi, Shantanu; Howard, John; Fhager, A.; Bengtsson, Sebastian

    2011-01-01

    This article presents the design and development of a personal computer based controller for a microwave tomographic system for breast cancer detection. The system uses motorized, dual-polarized antennas and a custom-made GUI interface to control stepper motors, a wideband vector network analyzer (VNA) and to coordinate data acquisition and archival in a local MDSPlus database. Both copolar and cross-polar scattered field components can be measured directly. Experimental results are presented to validate the various functionalities of the scanner.

  9. Multivariate analysis: A statistical approach for computations

    NASA Astrophysics Data System (ADS)

    Michu, Sachin; Kaushik, Vandana

    2014-10-01

    Multivariate analysis is a type of multivariate statistical approach commonly used in, automotive diagnosis, education evaluating clusters in finance etc and more recently in the health-related professions. The objective of the paper is to provide a detailed exploratory discussion about factor analysis (FA) in image retrieval method and correlation analysis (CA) of network traffic. Image retrieval methods aim to retrieve relevant images from a collected database, based on their content. The problem is made more difficult due to the high dimension of the variable space in which the images are represented. Multivariate correlation analysis proposes an anomaly detection and analysis method based on the correlation coefficient matrix. Anomaly behaviors in the network include the various attacks on the network like DDOs attacks and network scanning.

  10. Analysis of a Multiprocessor Guidance Computer. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Maltach, E. G.

    1969-01-01

    The design of the next generation of spaceborne digital computers is described. It analyzes a possible multiprocessor computer configuration. For the analysis, a set of representative space computing tasks was abstracted from the Lunar Module Guidance Computer programs as executed during the lunar landing, from the Apollo program. This computer performs at this time about 24 concurrent functions, with iteration rates from 10 times per second to once every two seconds. These jobs were tabulated in a machine-independent form, and statistics of the overall job set were obtained. It was concluded, based on a comparison of simulation and Markov results, that the Markov process analysis is accurate in predicting overall trends and in configuration comparisons, but does not provide useful detailed information in specific situations. Using both types of analysis, it was determined that the job scheduling function is a critical one for efficiency of the multiprocessor. It is recommended that research into the area of automatic job scheduling be performed.

  11. The Utility of Computer-Assisted Power Analysis Lab Instruction

    ERIC Educational Resources Information Center

    Petrocelli, John V.

    2007-01-01

    Undergraduate students (N = 47), enrolled in 2 separate psychology research methods classes, evaluated a power analysis lab demonstration and homework assignment. Students attended 1 of 2 lectures that included a basic introduction to power analysis and sample size analysis. One lecture included a demonstration of how to use a computer-based power…

  12. The Reliability of Content Analysis of Computer Conference Communication

    ERIC Educational Resources Information Center

    Rattleff, Pernille

    2007-01-01

    The focus of this article is the reliability of content analysis of students' computer conference communication. Content analysis is often used when researching the relationship between learning and the use of information and communications technology in educational settings. A number of studies where content analysis is used and classification…

  13. A fast multi-resolution approach to tomographic PIV

    NASA Astrophysics Data System (ADS)

    Discetti, Stefano; Astarita, Tommaso

    2012-03-01

    Tomographic particle image velocimetry (Tomo-PIV) is a recently developed three-component, three-dimensional anemometric non-intrusive measurement technique, based on an optical tomographic reconstruction applied to simultaneously recorded images of the distribution of light intensity scattered by seeding particles immersed into the flow. Nowadays, the reconstruction process is carried out mainly by iterative algebraic reconstruction techniques, well suited to handle the problem of limited number of views, but computationally intensive and memory demanding. The adoption of the multiplicative algebraic reconstruction technique (MART) has become more and more accepted. In the present work, a novel multi-resolution approach is proposed, relying on the adoption of a coarser grid in the first step of the reconstruction to obtain a fast estimation of a reliable and accurate first guess. A performance assessment, carried out on three-dimensional computer-generated distributions of particles, shows a substantial acceleration of the reconstruction process for all the tested seeding densities with respect to the standard method based on 5 MART iterations; a relevant reduction in the memory storage is also achieved. Furthermore, a slight accuracy improvement is noticed. A modified version, improved by a multiplicative line of sight estimation of the first guess on the compressed configuration, is also tested, exhibiting a further remarkable decrease in both memory storage and computational effort, mostly at the lowest tested seeding densities, while retaining the same performances in terms of accuracy.

  14. Computational fluid dynamics combustion analysis evaluation

    NASA Technical Reports Server (NTRS)

    Kim, Y. M.; Shang, H. M.; Chen, C. P.; Ziebarth, J. P.

    1992-01-01

    This study involves the development of numerical modelling in spray combustion. These modelling efforts are mainly motivated to improve the computational efficiency in the stochastic particle tracking method as well as to incorporate the physical submodels of turbulence, combustion, vaporization, and dense spray effects. The present mathematical formulation and numerical methodologies can be casted in any time-marching pressure correction methodologies (PCM) such as FDNS code and MAST code. A sequence of validation cases involving steady burning sprays and transient evaporating sprays will be included.

  15. Computational analysis of scramjet dual mode operation

    NASA Technical Reports Server (NTRS)

    1985-01-01

    One critical element in the design of a Scramjet is the detailed understanding of the complex flow field in the engine during various phases of operation. One area of interest is the computation of chemically reacting flows in the vicinity of flame holders. The characteristics of a method for solving the Navier-Stokes equations with chemical reactions are proposed. Also of interest are the flame holding characteristics of simple ramp and rearward facing steps. Both of these configurations are considered candidates for Scramjet flame holders.

  16. Computer-Based Interaction Analysis with DEGREE Revisited

    ERIC Educational Resources Information Center

    Barros, B.; Verdejo, M. F.

    2016-01-01

    We review our research with "DEGREE" and analyse how our work has impacted the collaborative learning community since 2000. Our research is framed within the context of computer-based interaction analysis and the development of computer-supported collaborative learning (CSCL) tools. We identify some aspects of our work which have been…

  17. Computer aided analysis and optimization of mechanical system dynamics

    NASA Technical Reports Server (NTRS)

    Haug, E. J.

    1984-01-01

    The purpose is to outline a computational approach to spatial dynamics of mechanical systems that substantially enlarges the scope of consideration to include flexible bodies, feedback control, hydraulics, and related interdisciplinary effects. Design sensitivity analysis and optimization is the ultimate goal. The approach to computer generation and solution of the system dynamic equations and graphical methods for creating animations as output is outlined.

  18. The symbolic computation and automatic analysis of trajectories

    NASA Technical Reports Server (NTRS)

    Grossman, Robert

    1991-01-01

    Research was generally done on computation of trajectories of dynamical systems, especially control systems. Algorithms were further developed for rewriting expressions involving differential operators. The differential operators involved arise in the local analysis of nonlinear control systems. An initial design was completed of the system architecture for software to analyze nonlinear control systems using data base computing.

  19. Simple hobby computer-based off-gas analysis system

    SciTech Connect

    Forrest, E.H.; Jansen, N.B.; Flickinger, M.C.; Tsao, G.T.

    1981-02-01

    An Apple II computer has been adapted to monitor fermentation offgas in laboratory and pilot scale fermentors. It can calculate oxygen uptake rates, carbon dioxide evolution rates, respiratory quotient as well as initiating recalibration procedures. In this report the computer-based off-gas analysis system is described.

  20. Potential applications of computational fluid dynamics to biofluid analysis

    NASA Technical Reports Server (NTRS)

    Kwak, D.; Chang, J. L. C.; Rogers, S. E.; Rosenfeld, M.; Kwak, D.

    1988-01-01

    Computational fluid dynamics was developed to the stage where it has become an indispensable part of aerospace research and design. In view of advances made in aerospace applications, the computational approach can be used for biofluid mechanics research. Several flow simulation methods developed for aerospace problems are briefly discussed for potential applications to biofluids, especially to blood flow analysis.