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Sample records for computed tomographic analysis

  1. Computed tomographic analysis of meteorite inclusions.

    PubMed

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

    1983-01-28

    The discovery of isotopic anomalies in the calcium- and aluminum-rich inclusions of the Allende meteorite has improved our knowledge of the origin of the solar system. Inability to find more inclusions without destroying the meteorite has hampered further study. By using a fourth-generation computed tomographic scanner with modifications to the software only, the interior of heterogeneous materials such as Allende can be nondestructively probed. 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.

  2. 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.

  3. Volume measurements of normal orbital structures by computed tomographic analysis

    SciTech Connect

    Forbes, G.; Gehring, D.G.; Gorman, C.A.; Brennan, M.D.; Jackson, I.T.

    1985-07-01

    Computed tomographic digital data and special off-line computer graphic analysis were used to measure volumes of normal orbital soft tissue, extraocular muscle, orbital fat, and total bony orbit in vivo in 29 patients (58 orbits). The upper limits of normal for adult bony orbit, soft tissue exclusive of the globe, orbital fat, and muscle are 30.1 cm/sup 3/, 20.0 cm/sup 3/, 14.4 cm/sup 3/, and 6.5 cm/sup 3/, respectively. There are small differences in men as a group compared with women but minimal difference between right and left orbits in the same person. The accuracy of the techniques was established at 7%-8% for these orbit structural volumes in physical phantoms and in simulated silicone orbit phantoms in dry skulls. Mean values and upper limits of normal for volumes were determined in adult orbital structures for future comparison with changes due to endocrine ophthalmopathy, trauma, and congenital deformity.

  4. 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.

  5. Leiomyosarcoma: computed tomographic findings

    SciTech Connect

    McLeod, A.J.; Zornoza, J.; Shirkhoda, A.

    1984-07-01

    The computed tomographic (CT) findings in 118 patients with the diagnosis of leiomyosarcoma were reviewed. The tumor masses visualized in these patients were often quite large; extensive necrotic or cystic change was a frequent finding. Calcification was not observed in these tumors. The liver was the most common site of metastasis in these patients, with marked necrosis of the liver lesions a common finding. Other manifestations of tumor spread included pulmonary metastases, mesenteric or omental metastases, retroperitoneal lymphadenopathy, soft-tissue metastases, bone metastases, splenic metastases, and ascites. Although the CT appearance of leiomyosarcoma is not specific, these findings, when present, suggest consideration of this diagnosis.

  6. Hemobilia: computed tomographic diagnosis

    SciTech Connect

    Krudy, A.G.; Doppman, J.L.; Bissonette, M.B.; Girton, M.

    1983-09-01

    A case of postbiopsy hemobilia is presented in which computed tomographic (CT) scanning showed blood within the gallbladder appearing as high-density material measuring 67-91 HU. Residual clots were seen by CT and ultrasound 8 days after the acute episode. These findings were confirmed by serial CT scans in two monkeys in whom blood was experimentally injected into the gallbladder. When the cystic duct is patent, the diagnosis of hemobilia may be excluded if bile of normal density (0-20 HU) is demonstrated by CT scanning. However, when homogeneous or inhomogeneous material of high attenuation (50+ HU) is present in the gallbladder on CT scanning, the diagnosis of hemobilia is strongly suggested if other causes such as stone or contrast material have been eliminated. CT may show residual blood for days after the acute episode.

  7. Predictors of internal mammary vessel diameter: A computed tomographic angiography-assisted anatomic analysis.

    PubMed

    Cook, Julia A; Tholpady, Sunil S; Momeni, Arash; Chu, Michael W

    2016-10-01

    The internal mammary vessels are the most common recipient vessels in free flap breast reconstruction. The literature on internal mammary vascular anatomy is limited by small sample sizes, cadaveric studies, or intraoperative changes. The purpose of this study is to analyze internal mammary anatomy using computed tomographic angiography. A retrospective review of 110 consecutive computed tomographic angiography studies of female patients was performed. Measurements of vessel caliber, distance of internal mammary vessels to sternum, location of internal mammary vein bifurcation, intercostal space height, and chest width were analyzed. Patient demographics and comorbidities were reviewed. The right internal mammary artery and vein were larger than the left in all intercostal spaces (p = 0.02 and p < 0.001, respectively). A significant correlation was found between both skeletal chest width and body mass index with internal mammary vessel caliber at the third intercostal space (p ≤ 0.02). The internal mammary vein bifurcated at the third intercostal space bilaterally, 4.3 and 1.2 mm caudal to the third rib on the right and left sides, respectively. The third intercostal space was <1.5 cm in 25% of patients. Understanding the anatomy, bifurcation, and caliber of internal mammary vessels can aid preoperative planning of autologous, free flap breast reconstruction. On average, the internal mammary vein bifurcates at the third intercostal space; patients with larger chest widths and body mass index had larger caliber internal mammary vessels, and 25% of patients had third intercostal space <1.5 cm and, thus, may not be suitable candidates for rib-sparing techniques. PMID:27475336

  8. 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.

  9. Dental computed tomographic imaging as age estimation: morphological analysis of the third molar of a group of Turkish population.

    PubMed

    Cantekin, Kenan; Sekerci, Ahmet Ercan; Buyuk, Suleyman Kutalmis

    2013-12-01

    Computed tomography (CT) is capable of providing accurate and measurable 3-dimensional images of the third molar. The aims of this study were to analyze the development of the mandibular third molar and its relation to chronological age and to create new reference data for a group of Turkish participants aged 9 to 25 years on the basis of cone-beam CT images. All data were obtained from the patients' records including medical, social, and dental anamnesis and cone-beam CT images of 752 patients. Linear regression analysis was performed to obtain regression formulas for dental age calculation with chronological age and to determine the coefficient of determination (r) for each sex. Statistical analysis showed a strong correlation between age and third-molar development for the males (r2 = 0.80) and the females (r2 = 0.78). Computed tomographic images are clinically useful for accurate and reliable estimation of dental ages of children and youth.

  10. 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.

  11. Computed tomographic angiography in tetralogy of Fallot.

    PubMed

    Kasar, Pankajkumar Ashok; Ravikumar, Radhakrishnan; Varghese, Roy; Kotecha, Monika; Vimala, Jesudian; Kumar, Raghavan Nair Suresh

    2011-10-01

    Echocardiography is often inadequate for imaging tetralogy of Fallot, prompting cineangiography. This study prospectively evaluated multidetector computed tomographic angiography for preoperative evaluation of tetralogy of Fallot in 112 consecutive patients. Forty-eight had nonconfluent or hypoplastic pulmonary arteries (mean z-score, -2; range, -11.1-0.13) permitting only palliative or no surgery; 64 had adequate pulmonary artery anatomy (mean z-score, 0.59; range, -2.53-3.4) allowing total repair. The surgical data of 50 patients who underwent total correction were compared with transthoracic echocardiography and multidetector computed tomographic angiography findings. Multidetector computed tomographic angiography tended to reveal unsuspected collaterals and coronary abnormalities besides outlining the right ventricular outflow tract and pulmonary artery branches. The branch pulmonary artery diameter z-score was the most important determinant of surgical strategy, with the worst figures being associated with no surgical options or palliative surgery, and the best figures leading to corrective surgery. The mean radiation dose was 3.45 mSv. Multidetector computed tomographic angiography is a powerful supplement to echocardiography in the preoperative evaluation of tetralogy of Fallot.

  12. 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.

  13. 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.

  14. Computed tomographic analysis of deformity and dimensional changes in the eyeball

    SciTech Connect

    Osborne, D.R.; Foulks, G.N.

    1984-12-01

    Computed tomography (CT) was performed in 40 patients with a confirmed ophthalmic diagnosis and a change in the dimensions or configuration of the eyeball. Abnormalities studied included coloboma, microphthalmus, buphthalmos, axial myopia, macrophthalmus, phthisis bulbi, trauma, neoplasm, posterior staphyloma, granuloma, pseudotumor, and surgicalscleral banding for retinal detachment. CT findings could be grouped into three categories depending upon whether the eye was small, large, or normal in size, with the findings in each group allowing distinction of most disease processes.

  15. 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

  16. Computed tomographic cephalometric analysis of Chinese patients with obstructive sleep apnoea.

    PubMed

    Peh, W C; Ip, M S; Chu, F S; Chung, K F

    2000-11-01

    Variations of craniofacial and upper airway structures are recognized to contribute to the phenomenon of obstructive sleep apnoea (OSA). Most previous cephalometric studies were performed using erect lateral radiographs in Caucasian patients. The present project aims to determine cephalometric measurements, utilizing CT, in normal Chinese subjects and in Chinese patients with OSA. Computed tomography of 25 patients with OSA (proven using overnight polysomnography), and of 25 age-, sex-, height-, bodyweight- and body mass index (BMI)-matched control subjects were prospectively performed. Thirteen standard bony and soft-tissue measurements were obtained from the CT lateral scout view of the head and neck, taken with each subject in the neutral supine position. The cross-sectional area was calculated at two axial levels (velopharynx and hypopharynx). The measurements in the two groups, OSA and control subjects, were compared. The measurements for hyoid position (P = 0.00), nasal cavity length (P = 0.01), mandibular prognathism (P = 0.05), tongue size (P = 0.02), oropharyngeal airway space (P = 0.02), posterior tongue airway space (P = 0.04) and cross-sectional areas at the level of the velopharynx (P = 0.00) and hypopharynx (P = 0.01) differed significantly between the two groups. In conclusion, CT cephalometric measurements show that certain anatomical variations in the head and neck are likely to contribute to the pathogenesis of OSA in Chinese patients.

  17. 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.

  18. Cranial computed tomographic abnormalities in leptomeningeal metastasis

    SciTech Connect

    Lee, Y.Y.; Glass, J.P.; Geoffray, A.; Wallace, S.

    1984-11-01

    Sixty-four (57.6%) of 111 cancer patients with cerebrospinal fluid cytology positive for malignant cells had cranial computed tomographic (CT) scans within 2 weeks before or after a lumbar puncture. Twenty-two (34.3%) of the 64 had abnormal CT findings indicative of leptomeningeal metastasis. Thirteen (59.6%) of these 22 patients had associated parenchymal metastases. Recognition of leptomeningeal disease may alter the management of patients with parenchymal metastases. Communicating hydrocephalus in cancer patients should be considered to be related to leptomeningeal metastasis until proven otherwise.

  19. Computed Tomographic Angiography of the Abdominal Aorta.

    PubMed

    Hansen, Neil J

    2016-01-01

    Computed tomographic (CT) angiography (CTA) has become the preferred imaging test of choice for various aortic conditions because of its excellent spatial resolution, rapid image acquisition, and its wide availability. CTA provides a robust tool for planning aortic interventions and diagnosing acute and chronic vascular diseases in the abdomen. CTA is the standard for imaging aneurysms before intervention and evaluating the aorta in the acute setting to assess traumatic injury, dissection, and aneurysm rupture. Knowledge of the imaging features of these disease processes, inflammatory vasculitides, and occlusive atherosclerotic disease is essential for guiding surgical and medical management of patients. PMID:26654390

  20. 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.

  1. Quantitative strain analysis in analogue modelling experiments: insights from X-ray computed tomography and tomographic image correlation

    NASA Astrophysics Data System (ADS)

    Adam, J.; Klinkmueller, M.; Schreurs, G.; Wieneke, B.

    2009-04-01

    deformation. We have adapted our analogue modelling setups for optimal analysis of complex deformation processes using leading-edge volumetric strain monitoring techniques (3D volume DIC, Tomographic DIC). In this study, we apply DIC on X-ray CT images of analogue models. Our first results indicate that DIC can successfully be applied to quantify the 2D and 3D spatial and temporal patterns of strain accumulation. REFERENCES Adam, J., Urai, J.L, Wieneke, B., Oncken, O., Pfeiffer, K., Kukowski, N., Lohrmann, J., Hoth, S. van der Zee, W., and Schmatz, J.; 2005: Shear localisation and strain distribution during tectonic faulting - new insights from granular-flow experiments and high-resolution optical image correlation techniques. Journal of Structural Geology, 27, 283-301. Lohrmann, J., Kukowski, N., Adam, J. & Oncken, O.; 2003: The control of sand wedges by material properties: sensitivity analyses and application to convergent margin mechanics. - Journal of Structural Geology, 25, 1691-1711 Panien, M., Schreurs, G., and Pfiffner, A.; 2006. Mechanical behaviour of granular materials used in analogue modelling: insights from grain characterisation, ring-shear tests and analogue experiments. Journal of Structural Geology, 28, 1710-1724. Schreurs, G., Hänni, R, and Vock, P.; 2002: Analogue modelling of transfer zones in fold and thrust belts: a 4-D analysis. In: Schellart, W.P. and Passchier, C. (eds). Analogue modelling of large-scale tectonic processes. Journal of the Virtual Explorer, 7, 67-73. Schreurs, G., Hänni, R, Panien, M. and Vock, P.; 2003: Analysis of analogue models by helical X-ray computed tomography. In: Mees, F., Swennen, R., Van Geet, M. and Jacobs, P. (eds). Applications of X-ray Computed Tomogaphy in Earth Sciences. Geological Society, London, Special Publications, 215, 213-223.

  2. Prognostic utility of coronary computed tomographic angiography

    PubMed Central

    Otaki, Yuka; Berman, Daniel S.; Min, James K.

    2013-01-01

    Coronary computed tomographic angiography (CCTA) employing CT scanners of 64-detector rows or greater represents a noninvasive method that enables accurate detection and exclusion of anatomically obstructive coronary artery disease (CAD), providing excellent diagnostic information when compared to invasive angiography. There are numerous potential advantages of CCTA beyond simply luminal stenosis assessment including quantification of atherosclerotic plaque volume as well as assessment of plaque composition, extent, location and distribution. In recent years, an array of studies has evaluated the prognostic utility of CCTA findings of CAD for the prediction of major adverse cardiac events, all-cause death and plaque instability. This prognostic information enhances risk stratification and, if properly acted upon, may improve medical therapy and/or behavioral changes that may enhance event-free survival. The goal of the present article is to summarize the current status of the prognostic utility of CCTA findings of CAD. PMID:23809386

  3. 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.

  4. Computed tomographic anatomy of the equine tarsus.

    PubMed

    Tomlinson, Julia E; Redding, W Rich; Berry, Clifford; Smallwood, James E

    2003-01-01

    The purpose of this study was to provide a detailed computed tomographic (CT) anatomic reference for the equine tarsus. CT examinations of the tarsal regions from four clinically and radiographically normal adult horses, which were euthanized for reasons not related to musculoskeletal disease, were included in the study. Limbs were removed at the level of midtibia, and 3-mm contiguous transverse CT images were obtained, starting at a level proximal to the tuber calcanei and continuing distally into the proximal metatarsus. Soft tissue and bone windows were used to image different anatomic features, including bones, joints, and various soft tissue components of the tarsus. Each transverse slice was compared with bone models and dissected specimens to assist in the accurate identification of specific structures. The results of the study consist of nine CT images of the equine tarsus. Each image incorporates labeled soft tissue and bone-window images, a directional compass indicating cranial (Cr) or dorsal (D) and lateral (L), and a reconstructed scout image indicating the level through which the transverse slice was made. PMID:12718352

  5. 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.

  6. Comparative Validity and Reproducibility Study of Various Landmark-Oriented Reference Planes in 3-Dimensional Computed Tomographic Analysis for Patients Receiving Orthognathic Surgery

    PubMed Central

    Lin, Hsiu-Hsia; Chuang, Ya-Fang; Weng, Jing-Ling; Lo, Lun-Jou

    2015-01-01

    Background Three-dimensional computed tomographic imaging has become popular in clinical evaluation, treatment planning, surgical simulation, and outcome assessment for maxillofacial intervention. The purposes of this study were to investigate whether there is any correlation among landmark-based horizontal reference planes and to validate the reproducibility and reliability of landmark identification. Materials and Methods Preoperative and postoperative cone-beam computed tomographic images of patients who had undergone orthognathic surgery were collected. Landmark-oriented reference planes including the Frankfort horizontal plane (FHP) and the lateral semicircular canal plane (LSP) were established. Four FHPs were defined by selecting 3 points from the orbitale, porion, or midpoint of paired points. The LSP passed through both the lateral semicircular canal points and nasion. The distances between the maxillary or mandibular teeth and the reference planes were measured, and the differences between the 2 sides were calculated and compared. The precision in locating the landmarks was evaluated by performing repeated tests, and the intraobserver reproducibility and interobserver reliability were assessed. Results A total of 30 patients with facial deformity and malocclusion—10 patients with facial symmetry, 10 patients with facial asymmetry, and 10 patients with cleft lip and palate—were recruited. Comparing the differences among the 5 reference planes showed no statistically significant difference among all patient groups. Regarding intraobserver reproducibility, the mean differences in the 3 coordinates varied from 0 to 0.35 mm, with correlation coefficients between 0.96 and 1.0, showing high correlation between repeated tests. Regarding interobserver reliability, the mean differences among the 3 coordinates varied from 0 to 0.47 mm, with correlation coefficients between 0.88 and 1.0, exhibiting high correlation between the different examiners. Conclusions The

  7. 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

  8. Computer-aided marginal artery detection on computed tomographic colonography

    NASA Astrophysics Data System (ADS)

    Wei, Zhuoshi; Yao, Jianhua; Wang, Shijun; Liu, Jiamin; Summers, Ronald M.

    2012-03-01

    Computed tomographic colonography (CTC) is a minimally invasive technique for colonic polyps and cancer screening. The marginal artery of the colon, also known as the marginal artery of Drummond, is the blood vessel that connects the inferior mesenteric artery with the superior mesenteric artery. The marginal artery runs parallel to the colon for its entire length, providing the blood supply to the colon. Detecting the marginal artery may benefit computer-aided detection (CAD) of colonic polyp. It can be used to identify teniae coli based on their anatomic spatial relationship. It can also serve as an alternative marker for colon localization, in case of colon collapse and inability to directly compute the endoluminal centerline. This paper proposes an automatic method for marginal artery detection on CTC. To the best of our knowledge, this is the first work presented for this purpose. Our method includes two stages. The first stage extracts the blood vessels in the abdominal region. The eigenvalue of Hessian matrix is used to detect line-like structures in the images. The second stage is to reduce the false positives in the first step. We used two different masks to exclude the false positive vessel regions. One is a dilated colon mask which is obtained by colon segmentation. The other is an eroded visceral fat mask which is obtained by fat segmentation in the abdominal region. We tested our method on a CTC dataset with 6 cases. Using ratio-of-overlap with manual labeling of the marginal artery as the standard-of-reference, our method yielded true positive, false positive and false negative fractions of 89%, 33%, 11%, respectively.

  9. Computed tomographic appearance of an oleothorax.

    PubMed Central

    Deboisblanc, B P; Burch, W C; Buechner, H A; Haponik, E F

    1988-01-01

    Sequelae of oleothorax, formerly used in the treatment of tuberculosis, may still be encountered. A patient is reported whose oleothorax, created 44 years previously, was demonstrated by computed tomography. Images PMID:3212755

  10. 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.

  11. [Multispiral computed tomographic semiotics of laryngeal cancer].

    PubMed

    Vasil'ev, P V; Iudin, A L; Sdvizhkov, A M; Kozhanov, L G

    2007-01-01

    Multispiral computed tomography (MSCT) with intravenous bolus contrasting is a currently available method for radiodiagnosis of laryngeal cancer. MSCT is of much higher informative value in estimating the extent of a tumorous lesion than the traditional radiodiagnostic techniques: linear tomography, lateral X-ray study, roentgenoscopy and roentgenography of the laryngopharynx and esophagus with barium meal.

  12. Computed tomographic findings in bourneville-pringle disease.

    PubMed

    Beltle, J; Seemann, Marcus D

    2003-07-31

    Bourneville-Pringle disease (synonym: tuberous sclerosis, epiploia) is a neuroectodermal disorder. A characteristic clinical triad of adenoma sebaceum, mental retardartion, and seizures leads to early childhood diagnosis. Many patients show morphological changes of the visceral organs, vascular, and skeletal system. We review the computed tomographic findings of Bourneville-Pringle disease as relates to an oligosymptomatic 36-year-old woman with late onset of clinical symptoms. PMID:12911865

  13. Cone Beam Computed Tomographic Analysis of the Shape, Height, and Location of the Mandibular Lingula in a Population of Children

    PubMed Central

    Sekerci, Ahmet Ercan; Cantekin, Kenan; Aydinbelge, Mustafa

    2013-01-01

     Objectives. This is the first study to identify and classify the different morphological shapes of the mandibular lingula (ML) in children using cone-beam computed tomography (CBCT). Material and Methods. A retrospective study was performed to evaluate the shape, height, and location of the ML in relation to the surrounding structures using CBCT images of mandibles obtained from 269 children. The shape of the ML was classified into triangular, truncated, nodular, or assimilated types. The location was determined by five distances. The height of the lingula was also measured from the lingular tip to the mandibular foramen. Results. A nodular shape of the ML was most commonly found (48.3%, n = 260) followed by truncated (23.4%, n = 126), assimilated (14.4%, n = 78), and triangular (13.7%, n = 74). The mean distance of ML from the anterior and posterior borders of mandibular ramus was 13.3 ± 2.3 mm and 10.2 ± 1.6 mm, respectively. In the majority of the mandibles studied, the ML was located above the occlusal plane. Conclusion. The present study provides new information to the literature concerning the shape, height, and location of the lingula in a Turkish pediatric population. This finding may assist clinicians to localize the lingula and avoid intraoperative complications. PMID:24490173

  14. CT features and common causes of arc of Riolan expansion: an analysis with 64-detector-row computed tomographic angiography

    PubMed Central

    Xie, Yuanliang; Jin, Chaolin; Zhang, Shutong; Wang, Xiang; Jiang, Yanping

    2015-01-01

    Objective: To study the manifestations of arc of Riolan expansion (ARE) using multi-detector computed tomography angiography (MDCTA). Materials and methods: The manifestations and clinical data of 626 consecutive mesentery CTA images were retrospectively analyzed. The 47 cases with ARE and 47 patients without expansion were involved. The average diameter of arc of Riolan was measured. Two radiologists after reaching consensus analyzed the shapes of mesenteric artery, CT findings and the occurrence and causes of ARE. Results: The mean diameter of arc of Riolan was 1.2 mm, 4.6 mm, 2.5 mm, 2.3 mm, 1.9 mm, 2.5 mm, and 2.0 mm at baseline and following obstruction of superior mesenteric artery (SMA), stenosis of SMA, obstruction of inferior mesenteric artery (IMA), stenosis of IMA, colon cancer, and active ulcerative colitis, respectively. The expansion of arc of Riolan was the most significant following obstruction of SMA. The diameters of arc of Riolan were significantly different between the upward flow group and the downward or the two-way flow groups, and between the colon tumor group and the active ulcerative colitis group. CT findings such as bowel wall thickening, contrast enhancement, intestinal obstruction, marginal artery expansion, lymph node enlargement varied and were help to identify the cause of ARE. Conclusions: ARE often suggests the occurrence of obstructed intestinal feeding artery or intestinal lesions. MDCTA can clearly display the situation of arc of Riolan and collateral circulation, and together with CT symptoms, can guide the selection of diagnosis and treatment schemes in clinic. PMID:26064208

  15. 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

  16. Computed tomographic appearance of resectable pancreatic carcinoma

    SciTech Connect

    Itai, Y.; Araki, T.; Tasaka, A.; Maruyama, M.

    1982-06-01

    Thirteen patients with resectable pancreatic carcinoma were examined by computed tomography (CT). Nine had a mass, 2 had dilatation of the main pancreatic duct, 1 appeared to have ductal dilatation, and 1 had no sign of abnormality. Resectable carcinoma was diagnosed retrospectively in 8 cases, based on the following criteria: a mass with a distinct contour, frequently containing a tiny or irregular low-density area and accompanied by dilatation of the caudal portion of the main pancreatic duct without involvement of the large vessels, liver, or lymph nodes. Including unresectable cancer, chronic pancreatitis, and obstructive jaundice from causes other than cancer, the false-positive rate was less than 6%. However, a small cancer without change in pancreatic contour is difficult to detect with CT.

  17. 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.

  18. Computed tomographic anatomy of the temporal bone

    SciTech Connect

    Virapongse, C.; Rothman, S.L.G.; Kier, E.L.; Sarwar, M.

    1982-10-01

    With the recent development of high-resolution computed tomography (CT), there is a growing need to explore the full potential of this new method in demonstrating the detailed anatomy of the temporal bone. For this purpose, dry skulls with intact ossicles were scanned in axial and coronal projections. The detailed CT anatomy of the temporal bone was documented, complemented by images from live patients. Because of its superior contrast resolution, CT was able to demonstrate numerous structures, such as the tympanic membrane, ossicles, and supporting structures, hitherto never or poorly visualized by any other method. In addition, the ease by which axial sections of the temporal bone could be obtained is of great benefit in displaying several structures previously difficult to evaluate.

  19. Computer-tomographic evaluation of gynecologic tumors.

    PubMed

    Kormano, M; Grönroos, M

    1984-01-01

    The accuracy of contrast-enhanced computer tomography (CT) of the pelvis in the detection, characterization and staging of known or suspected pelvic tumors was compared with clinical and operative findings in a prospective study of 79 patients (25 cervical carcinomas, 27 endometrial carcinomas, 10 ovarian carcinomas, 4 vulval or vaginal carcinomas and 13 benign ovarian or uterine tumors). In cervical carcinoma, there was a tendency towards lower staging of the tumor, especially in stage IIa, which is not easily detected in CT. Even small tumors of the cervix and endometrium can be visualized by contrast enhancement, which clearly delineates heavily vascularized myometrium and less enhancing tumor tissue. The accuracy of CT in tumor detection, characterization and evaluation of spread was best in ovarian neoplasms, weakest in cervical carcinomas. The importance of proper CT technique is stressed.

  20. [Computed tomographic semiotics of chronic subdural hematomas].

    PubMed

    El'-Kadi, Kh A; Likhterman, L B; Kornichenko, V N

    1990-01-01

    Analysis of the results of investigation of 72 patients with verified chronic subdural hematomas (CSH) has revealed their CT dense characteristics, the peculiarities of their structure compared with the time of their formation, the patients' age, the clinical stage of disease, and operative findings. Direct and indirect CT signs of uni- and bilateral hemispherical chronic subdural hematomas were described.

  1. 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.

  2. 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

  3. Technical innovation: Multidimensional computerized software enabled subtraction computed tomographic angiography.

    PubMed

    Bhatia, Mona; Rosset, Antoine; Platon, Alexandra; Didier, Dominique; Becker, Christoph D; Poletti, Pierre-Alexandre

    2010-01-01

    Computed tomographic angiography (CTA) is a frequent noninvasive alternative to digital subtraction angiography. We previously reported the development of a new subtraction software to overcome limitations of adjacent bone and calcification in CT angiographic subtraction. Our aim was to further develop and improve this fast and automated computerized software, universally available for free use and compatible with most CT scanners, thus enabling better delineation of vascular structures, artifact reduction, and shorter reading times with potential clinical benefits. This computer-based free software will be available as an open source in the next release of OsiriX at the Web site http://www.osirix-viewer.com.

  4. 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.

  5. 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.

  6. Cardiac computed tomographic angiography and the primary care physician.

    PubMed

    Mikolich, J Ronald

    2012-05-01

    Through advancements in computer processing speed and storage capacity, new cardiac imaging modalities have become clinically feasible and useful. Cardiac computed tomographic angiography, a new diagnostic imaging modality, is capable of assessing coronary artery disease and left ventricular function on a par with invasive coronary arteriography in selected patients who meet appropriate use criteria. This imaging modality is of clinical value in the assessment of patients with chest pain who have an intermediate risk of coronary atherosclerosis. The purpose of the present report is to educate primary care physicians about the basic principles of advanced cardiac imaging techniques and to convey a useful strategy for their appropriate use in the current environment of medical economics.

  7. 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.

  8. Pancreatic lesions and transfascial perirenal spread: computed tomographic demonstration.

    PubMed

    Feldberg, M A; Hendriks, M J; van Waes, P F; Sung, K J

    1987-01-01

    Computed tomographic (CT) findings in 105 cases of pancreatitis and 107 cases of pancreatic carcinoma were analyzed retrospectively to determine the occurrence and roentgenologic signs of penetration of the anterior renal fascial planes in relation to clinical symptoms. In pancreatitis, the perirenal fat was infiltrated in 7% to variable extents by extrapancreatic fluid collections, either as asymptomatic fluid lying alongside renal fascial planes and perirenal septa (5 cases) or as well-circumscribed fluid collections causing clinical symptoms (2 cases). In pancreatic carcinoma the occurrence of retropancreatic extension to a perirenal space was rarer (3%). Distinction on CT between perirenal involvement from the pancreas and primary adrenal or renal lesions with anterior spread can prevent unnecessary surgery.

  9. 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

  10. Computer vision approach to detect colonic polyps in computed tomographic colonography

    NASA Astrophysics Data System (ADS)

    McKenna, Matthew T.; Wang, Shijun; Nguyen, Tan B.; Burns, Joseph E.; Petrick, Nicholas; Sahiner, Berkman; Summers, Ronald M.

    2012-03-01

    In this paper, we present evaluation results for a novel colonic polyp classification method for use as part of a computed tomographic colonography (CTC) computer-aided detection (CAD) algorithm. Inspired by the interpretative methodology of radiologists using 3D fly-through mode in CTC reading, we have developed an algorithm which utilizes sequences of images (referred to here as videos) for classification of CAD marks. First, we generated an initial list of polyp candidates using an existing CAD system. For each of these candidates, we created a video composed of a series of intraluminal, volume-rendered images focusing on the candidate from multiple viewpoints. These videos illustrated the shape of the polyp candidate and gathered contextual information of diagnostic importance. We calculated the histogram of oriented gradients (HOG) feature on each frame of the video and utilized a support vector machine for classification. We tested our method by analyzing a CTC data set of 50 patients from three medical centers. Our proposed video analysis method for polyp classification showed significantly better performance than an approach using only the 2D CT slice data. The areas under the ROC curve for these methods were 0.88 (95% CI: [0.84, 0.91]) and 0.80 (95% CI: [0.75, 0.84]) respectively (p=0.0005).

  11. 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

  12. Multidetector computed tomographic angiography of aberrant subclavian arteries.

    PubMed

    Türkvatan, Aysel; Büyükbayraktar, Fatma Gül; Olçer, Tülay; Cumhur, Turhan

    2009-02-01

    The purpose of this study was to evaluate the utility of 16-slice multidetector computed tomographic (MDCT) angiography for identifying anatomic features of aberrant subclavian arteries. Seventeen patients with aberrant subclavian arteries were assessed by MDCT angiography. The aortic arch position, the presence of a Kommerell's diverticulum, aneurysm, vascular compression of trachea and oesophagus and associated cardiovascular abnormalities were evaluated. MDCT findings were confirmed by surgery in eight patients but in the other nine patients no further evaluation or management was warranted as the aberrant subclavian artery had no significant clinical consequence. Eleven patients had an aberrant right subclavian artery arising from the left aortic arch and six patients had an aberrant left subclavian artery arising from the right aortic arch. Kommerell's diverticulum was identified in three patients with an aberrant right subclavian artery and in five patients with an aberrant left subclavian artery. In two patients it was aneurysmal. Oesophageal compression was detected in eight patients, and tracheal compression was identified in only one paediatric patient. An aberrant subclavian artery was associated with complex congenital heart disease in one patient, intracardiac defects in two patients, aortic coarctation in two patients, patent ductus arteriosus in two patients and an aberrant vertebral artery in one patient. In conclusion, MDCT angiography is superior to digital subtraction angiography for the assessment of aberrant subclavian arteries since digital subtraction angiography has only a poor ability to visualize adjacent structures completely and is invasive in nature. MDCT angiography or magnetic resonance angiography are the current standard in the initial evaluation of thoracic vascular anomalies.

  13. Electron tomographic analysis of synaptic ultrastructure.

    PubMed

    Burette, Alain C; Lesperance, Thomas; Crum, John; Martone, Maryann; Volkmann, Niels; Ellisman, Mark H; Weinberg, Richard J

    2012-08-15

    Synaptic function depends on interactions among sets of proteins that assemble into complex supramolecular machines. Molecular biology, electrophysiology, and live-cell imaging studies have provided tantalizing glimpses into the inner workings of the synapse, but fundamental questions remain regarding the functional organization of these "nano-machines." Electron tomography reveals the internal structure of synapses in three dimensions with exceptional spatial resolution. Here we report results from an electron tomographic study of axospinous synapses in neocortex and hippocampus of the adult rat, based on aldehyde-fixed material stabilized with tannic acid in lieu of postfixation with osmium tetroxide. Our results provide a new window into the structural basis of excitatory synaptic processing in the mammalian brain. PMID:22684938

  14. 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

  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. Computed tomographic findings of cerebral fat embolism following multiple bone fractures.

    PubMed

    Law, Huong Ling; Wong, Siong Lung; Tan, Suzet

    2013-02-01

    Fat embolism to the lungs and brain is an uncommon complication following fractures. Few reports with descriptions of computed tomographic (CT) findings of emboli to the brain or cerebral fat embolism are available. We report a case of cerebral fat embolism following multiple skeletal fractures and present its CT findings here.

  19. Computed Tomographic Airway Morphology in Chronic Obstructive Pulmonary Disease. Remodeling or Innate Anatomy?

    PubMed

    Diaz, Alejandro A; Estépar, Raul San José; Washko, George R

    2016-01-01

    Computed tomographic measures of central airway morphology have been used in clinical, epidemiologic, and genetic investigation as an inference of the presence and severity of small-airway disease in smokers. Although several association studies have brought us to believe that these computed tomographic measures reflect airway remodeling, a careful review of such data and more recent evidence may reveal underappreciated complexity to these measures and limitations that prompt us to question that belief. This Perspective offers a review of seminal papers and alternative explanations of their data in the light of more recent evidence. The relationships between airway morphology and lung function are observed in subjects who never smoked, implying that native airway structure indeed contributes to lung function; computed tomographic measures of central airways such as wall area, lumen area, and total bronchial area are smaller in smokers with chronic obstructive pulmonary disease versus those without chronic obstructive pulmonary disease; and the airways are smaller as disease severity increases. The observations suggest that (1) native airway morphology likely contributes to the relationships between computed tomographic measures of airways and lung function; and (2) the presence of smaller airways in those with chronic obstructive pulmonary disease versus those without chronic obstructive pulmonary disease as well as their decrease with disease severity suggests that smokers with chronic obstructive pulmonary disease may simply have smaller airways to begin with, which put them at greater risk for the development of smoking-related disease.

  20. The spectrum of computed tomographic appearance of metastatic masses from testicular neoplasms.

    PubMed

    Zingas, A P; Jain, A B; Loredo, R D; Kling, G A

    1984-01-01

    Metastatic masses from testicular neoplasms were evaluated with respect to their computed tomographic characteristics. They were divided in three categories: cystic, semicystic, and solid. The common denominator in the first two categories was the presence of teratomatous components. The nonteratomatous masses were solid.

  1. Parallel computing for simultaneous iterative tomographic imaging by graphics processing units

    NASA Astrophysics Data System (ADS)

    Bello-Maldonado, Pedro D.; López, Ricardo; Rogers, Colleen; Jin, Yuanwei; Lu, Enyue

    2016-05-01

    In this paper, we address the problem of accelerating inversion algorithms for nonlinear acoustic tomographic imaging by parallel computing on graphics processing units (GPUs). Nonlinear inversion algorithms for tomographic imaging often rely on iterative algorithms for solving an inverse problem, thus computationally intensive. We study the simultaneous iterative reconstruction technique (SIRT) for the multiple-input-multiple-output (MIMO) tomography algorithm which enables parallel computations of the grid points as well as the parallel execution of multiple source excitation. Using graphics processing units (GPUs) and the Compute Unified Device Architecture (CUDA) programming model an overall improvement of 26.33x was achieved when combining both approaches compared with sequential algorithms. Furthermore we propose an adaptive iterative relaxation factor and the use of non-uniform weights to improve the overall convergence of the algorithm. Using these techniques, fast computations can be performed in parallel without the loss of image quality during the reconstruction process.

  2. 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

  3. Prognostic capabilities of coronary computed tomographic angiography before non-cardiac surgery: prospective cohort study

    PubMed Central

    Chan, Matthew; Butler, Craig; Chow, Benjamin; Tandon, Vikas; Nagele, Peter; Mitha, Ayesha; Mrkobrada, Marko; Szczeklik, Wojciech; Faridah, Yang; Biccard, Bruce; Stewart, Lori K; Heels-Ansdell, Diane; Devereaux, P J

    2015-01-01

    Objectives To determine if coronary computed tomographic angiography enhances prediction of perioperative risk in patients before non-cardiac surgery and to assess the preoperative coronary anatomy in patients who experience a myocardial infarction after non-cardiac surgery. Design Prospective cohort study. Setting 12 centers in eight countries. Participants 955 patients with, or at risk of, atherosclerotic disease who underwent non-cardiac surgery. Interventions Coronary computed tomographic angiography was performed preoperatively; clinicians were blinded to the results unless left main disease was suspected. Results were classified as normal, non-obstructive (<50% stenosis), obstructive (one or two vessels with ≥50% stenosis), or extensive obstructive (≥50% stenosis in two vessels including the proximal left anterior descending artery, three vessels, or left main). Main outcome measure Composite of cardiovascular death and non-fatal myocardial infarction within 30 days after surgery (primary outcome). This was the dependent variable in Cox regression. The independent variables were scores on the revised cardiac risk index and findings on coronary computed tomographic angiography. Results The primary outcome occurred in 74 patients (8%). The model that included both scores on the revised cardiac risk index and findings on coronary computed tomographic angiography showed that coronary computed tomographic angiography provided independent prognostic information (P=0.014; C index=0.66). The adjusted hazard ratios were 1.51 (95% confidence interval 0.45 to 5.10) for non-obstructive disease; 2.05 (0.62 to 6.74) for obstructive disease; and 3.76 (1.12 to 12.62) for extensive obstructive disease. For the model with coronary computed tomographic angiography compared with the model based on the revised cardiac risk index alone, with 30 day risk categories of <5%, 5-15%, and >15% for the primary outcome, the results of risk reclassification indicate that in a sample of

  4. Constraining cosmology with shear peak statistics: tomographic analysis

    NASA Astrophysics Data System (ADS)

    Martinet, Nicolas; Bartlett, James G.; Kiessling, Alina; Sartoris, Barbara

    2015-09-01

    The abundance of peaks in weak gravitational lensing maps is a potentially powerful cosmological tool, complementary to measurements of the shear power spectrum. We study peaks detected directly in shear maps, rather than convergence maps, an approach that has the advantage of working directly with the observable quantity, the galaxy ellipticity catalog. Using large numbers of numerical simulations to accurately predict the abundance of peaks and their covariance, we quantify the cosmological constraints attainable by a large-area survey similar to that expected from the Euclid mission, focusing on the density parameter, Ωm, and on the power spectrum normalization, σ8, for illustration. We present a tomographic peak counting method that improves the conditional (marginal) constraints by a factor of 1.2 (2) over those from a two-dimensional (i.e., non-tomographic) peak-count analysis. We find that peak statistics provide constraints an order of magnitude less accurate than those from the cluster sample in the ideal situation of a perfectly known observable-mass relation; however, when the scaling relation is not known a priori, the shear-peak constraints are twice as strong and orthogonal to the cluster constraints, highlighting the value of using both clusters and shear-peak statistics.

  5. Performance of computed tomographic colonography improved by total quality management techniques

    NASA Astrophysics Data System (ADS)

    Garry, John L.; Reed, Judd E.; Johnson, C. Daniel

    2000-04-01

    Our institution has been using an internally developed system for the analysis of Computed Tomographic Colonography (CTC) since 1994. This system has gone through several major revisions during that period. Careful application of 'total quality management' (TQM) principles have been utilized to enhance such aspects of performance as patient comfort, latency between examination and reporting of results, capability and reliability of 'picture archive system' (PACS) and network components, as well as reliability of results. CTC is now being practiced at our institution for clinical screening and research applications. To date, 1500 patients have been scanned. On an average day, six patients are scanned for research and/or clinical purposes. Research patient data remain on the CTC workstation for future analysis by the Radiologists while clinical patient data are analyzed as soon as the data have been received at the CTC workstation. An enlarged dynamic axial stack augmented by multiple interactive, off axis reformatted and perspective volume rendered endoluminal views have proven to be the most effective reading mode. Well over 1000 patient scans have been analyzed utilizing this specific protocol. When compared to corresponding patient BE and/or Colonoscopy procedures, CTC findings of potential cancers and polyps have compared very favorably.

  6. Involution of juvenile nasopharyngeal angiofibroma with intracranial extension. A case report with computed tomographic assessment.

    PubMed

    Jacobsson, M; Petruson, B; Ruth, M; Svendsen, P

    1989-02-01

    In September 1979 the patient, a man born in 1964, noticed pain and swelling of the right cheek in combination with periods of epistaxis. A computed tomographic scan revealed a tumor extending from the middle of the right nasal cavity into the right maxillary antrum and up toward the orbital floor with destruction of the medial and lateral walls of the antrum and continuing into the sphenoid sinus on the right side and dorsal to the pterygoid process up under the base of the skull. Angiography showed arterial supply mainly from the right external carotid artery, but also from the right internal carotid artery and the left external carotid artery. The process was diagnosed as a juvenile nasopharyngeal angiofibroma. In spite of two attempts at resection of the tumor and arterial embolization, the tumor progressed intracranially. Further operative attempts were decided against, and the patient was followed with repeated computed tomographic scans. The tumor eventually became involuted; eight years after the initial diagnosis, there was no evidence of computed tomographic scans of intracranial growth of the tumor.

  7. Microphthalmos with cyst: clinical presentations and computed tomographic findings.

    PubMed

    Weiss, A; Martinez, C; Greenwald, M

    1985-01-01

    Four patients with microphthalmos with cyst were examined and evaluated by computed tomography (CT). Each patient had a different clinical presentation, which varied according to the appearance of the anterior segment and the size and location of the orbital cyst. All had very poor vision in the involved eye. CT was of great value in the diagnosis and definition of this condition. The differentiation of microphthalmos with cyst from coloboma and from other orbital masses by means of CT is discussed.

  8. 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.

  9. 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.

  10. Computed tomographic evaluation of silicosis and coal workers' pneumoconiosis

    SciTech Connect

    Remy-Jardin, M.; Remy, J.; Farre, I.; Marquette, C.H. )

    1992-11-01

    The introduction of computed tomography (CT) has modified the radiologic approach to silicosis and coal worker's pneumoconiosis considerably, allowing earlier recognition and more precise characterization of pulmonary abnormalities than chest radiography. An optimal approach to CT recognition requires an understanding of the main physiologic and pathologic features that are known to occur in both pneumoconioses. This report focuses on the most common CT features of simple and complicated forms of silicosis and coal worker's pneumoconiosis as well as on the optimal scanning protocol. The respective roles of chest radiographs and CT scans in the recognition of pneumoconiosis and follow-up of exposed workers are discussed.58 references.

  11. Computed tomographic images of discospondylitis in a calf

    PubMed Central

    TSUKA, Takeshi; YAMAMOTO, Naoki; SANESHIGE, Makoto; MORITA, Takehito; SUNDEN, Yuji; MURAHATA, Yusuke; AZUMA, Kazuo; OSAKI, Tomohiro; ITO, Norihito; OKAMOTO, Yoshiharu; IMAGAWA, Tomohiro

    2015-01-01

    A 2-month-old male Japanese Black calf was presented with a 30-day history of progressive ataxia. Antemortem examination using computed tomography (CT) revealed narrowing of the disc spaces due to destruction of intervertebral structures between the first and second thoracic vertebrae and between the second and third thoracic vertebrae. Osteolysis was evident as irregular hypoattenuating lesions within the opposing end plates of the first, second and third thoracic vertebrae. Pseudomonas aeruginosa was detected as the causative bacteria, and discospondylitis was diagnosed. To the best of our knowledge, this is the first bovine case report describing the application of CT for the diagnosis of discospondylitis. PMID:26256229

  12. Concentric reduction of the dislocated hip: computed tomographic evaluation

    SciTech Connect

    Hernandez, R.J.

    1984-01-01

    Concentric reduction of a dislocated hip can be evaluated by anteroposterior views or linear tomography. Anterior relationships, however, may be difficult to evaluate from a frontal radiograph despite good visibility. Computed tomography (CT), because of its cross-sectional imaging capabilities, is superior in demonstrating these relationships. The CT appearance of two types of dislocations (posterior and lateral ) is described. A posterior dislocation should be suspected if the femoral metaphysis approximates the acetabulum, a mass projects behind the ischium, or the fat plane anterior to the gluteus maximus is deformed or displaced posteriorly.

  13. [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

  14. [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

  15. Hybrid computing: CPU+GPU co-processing and its application to tomographic reconstruction.

    PubMed

    Agulleiro, J I; Vázquez, F; Garzón, E M; Fernández, J J

    2012-04-01

    Modern computers are equipped with powerful computing engines like multicore processors and GPUs. The 3DEM community has rapidly adapted to this scenario and many software packages now make use of high performance computing techniques to exploit these devices. However, the implementations thus far are purely focused on either GPUs or CPUs. This work presents a hybrid approach that collaboratively combines the GPUs and CPUs available in a computer and applies it to the problem of tomographic reconstruction. Proper orchestration of workload in such a heterogeneous system is an issue. Here we use an on-demand strategy whereby the computing devices request a new piece of work to do when idle. Our hybrid approach thus takes advantage of the whole computing power available in modern computers and further reduces the processing time. This CPU+GPU co-processing can be readily extended to other image processing tasks in 3DEM.

  16. Sonographic and computed tomographic evaluation of intrahepatic calculi

    SciTech Connect

    Menu, Y.; Lorphelin, J.M.; Scherrer, A.; Grenier, P.; Nahum, H.

    1985-09-01

    Intrahepatic calculi in non-Asian patients were studied by sonography and computed tomography (CT). Three patients were studied by CT cholangiography also. In two cases, the calculi were consecutive to Caroli disease, and in two others, the biliary stones were formed proximal to a stenosis of a previous surgical anastomosis. Five patients spontaneously developed intrahepatic calculi. All sonograms were abnormal. Image specificity was good, even when bile ducts were not dilated, if appropriate technique allowed identification of a double-arc-shadow pattern. Sonography strongly suggested the diagnosis in eight patients and was nonspecific in only one. On CT, calculi had various densities, and they were not visible in two patients. CT cholangiography was not particularly helpful. Both examinations strongly underestimate the number of stones, and direct cholangiography remains indicated if surgery is planned.

  17. 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.

  18. 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.

  19. 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.

  20. 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. PMID:27559345

  1. 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

  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. 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.

  4. Clinical Evaluation of Soft Tissue Organ Boundary Visualization on Cone-Beam Computed Tomographic Imaging

    SciTech Connect

    Weiss, Elisabeth; Wu Jian; Sleeman, William; Bryant, Joshua; Mitra, Priya; Myers, Michael; Ivanova, Tatjana; Mukhopadhyay, Nitai; Ramakrishnan, Viswanathan; Murphy, Martin; Williamson, Jeffrey

    2010-11-01

    Purpose: Cone-beam computed tomographic images (CBCTs) are increasingly used for setup correction, soft tissue targeting, and image-guided adaptive radiotherapy. However, CBCT image quality is limited by low contrast and imaging artifacts. This analysis investigates the detectability of soft tissue boundaries in CBCT by performing a multiple-observer segmentation study. Methods and Materials: In four prostate cancer patients prostate, bladder and rectum were repeatedly delineated by five observers on CBCTs and fan-beam CTs (FBCTs). A volumetric analysis of contouring variations was performed by calculating coefficients of variation (COV: standard deviation/average volume). The topographical distribution of contouring variations was analyzed using an average surface mesh-based method. Results: Observer- and patient-averaged COVs for FBCT/CBCT were 0.09/0.19 for prostate, 0.05/0.08 for bladder, and 0.09/0.08 for rectum. Contouring variations on FBCT were significantly smaller than on CBCT for prostate (p < 0.03) and bladder (p < 0.04), but not for rectum (p < 0.37; intermodality differences). Intraobserver variations from repeated contouring of the same image set were not significant for either FBCT or CBCT (p < 0.05). Average standard deviations of individual observers' contour differences from average surface meshes on FBCT vs. CBCT were 1.5 vs. 2.1 mm for prostate, 0.7 vs. 1.4 mm for bladder, and 1.3 vs. 1.5 mm for rectum. The topographical distribution of contouring variations was similar for FBCT and CBCT. Conclusion: Contouring variations were larger on CBCT than FBCT, except for rectum. Given the well-documented uncertainty in soft tissue contouring in the pelvis, improvement of CBCT image quality and establishment of well-defined soft tissue identification rules are desirable for image-guided radiotherapy.

  5. 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.

  6. 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.

  7. Modeling aspects and computational methods for some recent problems of tomographic imaging

    NASA Astrophysics Data System (ADS)

    Allmaras, Moritz

    In this dissertation, two recent problems from tomographic imaging are studied, and results from numerical simulations with synthetic data are presented. The first part deals with ultrasound modulated optical tomography, a method for imaging interior optical properties of partially translucent media that combines optical contrast with ultrasound resolution. The primary application is the optical imaging of soft tissue, for which scattering and absorption rates contain important functional and structural information about the physiological state of tissue cells. We developed a mathematical model based on the diffusion approximation for photon propagation in highly scattering media. Simple reconstruction schemes for recovering optical absorption rates from boundary measurements with focused ultrasound are presented. We show numerical reconstructions from synthetic data generated for mathematical absorption phantoms. The results indicate that high resolution imaging with quantitatively correct values of absorption is possible. Synthetic focusing techniques are suggested that allow reconstruction from measurements with certain types of non-focused ultrasound signals. A preliminary stability analysis for a linearized model is given that provides an initial explanation for the observed stability of reconstruction. In the second part, backprojection schemes are proposed for the detection of small amounts of highly enriched nuclear material inside 3D volumes. These schemes rely on the geometrically singular structure that small radioactive sources represent, compared to natural background radiation. The details of the detection problem are explained, and two types of measurements, collimated and Compton-type measurements, are discussed. Computationally, we implemented backprojection by counting the number of particle trajectories intersecting each voxel of a regular rectangular grid covering the domain of detection. For collimated measurements, we derived confidence

  8. 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.

  9. Computer-aided detection of pulmonary embolism in computed tomographic pulmonary angiography (CTPA): performance evaluation with independent data sets.

    PubMed

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

    2009-08-01

    The authors are developing a computer-aided detection system for pulmonary emboli (PE) in computed tomographic pulmonary angiography (CTPA) scans. The pulmonary vessel tree is extracted using a 3D expectation-maximization segmentation method based on the analysis of eigen-values of Hessian matrices at multiple scales. A parallel multiprescreening method is applied to the segmented vessels to identify volume of interests (VOIs) that contained suspicious PE. A linear discriminant analysis (LDA) classifier with feature selection is designed to reduce false positives (FPs). Features that characterize the contrast, gray level, and size of PE are extracted as input predictor variables to the LDA classifier. With the IRB approval, 59 CTPA PE cases were collected retrospectively from the patient files (UM cases). With access permission, 69 CTPA PE cases were randomly selected from the data set of the prospective investigation of pulmonary embolism diagnosis (PIOPED) II clinical trial. Extensive lung parenchymal or pleural diseases were present in 22/59 UM and 26/69 PIOPED cases. Experienced thoracic radiologists manually marked 595 and 800 PE as the reference standards in the UM and PIOPED data sets, respectively. PE occlusion of arteries ranged from 5% to 100%, with PE located from the main pulmonary artery to the subsegmental artery levels. Of the 595 PE identified in the UM cases, 245 and 350 PE were located in the subsegmental arteries and the more proximal arteries, respectively. The detection performance was assessed by free response ROC (FROC) analysis. The FROC analysis indicated that the PE detection system could achieve an overall sensitivity of 80% at 18.9 FPs/case for the PIOPED cases when the LDA classifier was trained with the UM cases. The test sensitivity with the UM cases was 80% at 22.6 FPs/cases when the LDA classifier was trained with the PIOPED cases. The detection performance depended on the arterial level where the PE was located and on the

  10. 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.

  11. Computed tomographic angiography in evaluation of superficial temporal to middle cerebral artery bypass.

    PubMed

    Besachio, David A; Ziegler, Jordan I; Duncan, Timothy D; Wanebo, John S

    2010-01-01

    Catheter-directed digital subtraction angiography (DSA) is considered the standard for evaluation of superficial temporal to middle cerebral artery (STA-MCA) bypass patency. Few clinical investigations have been performed that evaluate the efficacy of computed tomographic angiography (CTA) in the assessment of extracranial-intracranial bypass. Using multi-detector row CTA, STA-MCA bypass patency was assessed in the initial postoperative period and several months afterward and compared with DSA. No significant difference was identified in the evaluation of graft patency between DSA and CTA. Although multiple modalities exist to evaluate STA-MCA bypass graft patency, the multidetector CTA is widely available and allows for rapid, accurate patency assessment. PMID:20498550

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. Stature estimation from skull measurements using multidetector computed tomographic images: A Japanese forensic sample.

    PubMed

    Torimitsu, Suguru; Makino, Yohsuke; Saitoh, Hisako; Sakuma, Ayaka; Ishii, Namiko; Yajima, Daisuke; Inokuchi, Go; Motomura, Ayumi; Chiba, Fumiko; Yamaguchi, Rutsuko; Hashimoto, Mari; Hoshioka, Yumi; Iwase, Hirotaro

    2016-01-01

    The aim of this study was to assess the correlation between stature and cranial measurements in a contemporary Japanese population, using three-dimensional (3D) computed tomographic (CT) images. A total of 228 cadavers (123 males, 105 females) underwent postmortem CT scanning and subsequent forensic autopsy between May 2011 and April 2015. Five cranial measurements were taken from 3D CT reconstructed images that extracted only cranial data. The correlations between stature and each of the cranial measurements were assessed with Pearson product-moment correlation coefficients. Simple and multiple regression analyses showed significant correlations between stature and cranial measurements. In conclusion, cranial measurements obtained from 3D CT images may be useful for forensic estimation of the stature of Japanese individuals, particularly in cases where better predictors, such as long bones, are not available.

  18. 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.

  19. 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

  20. Automatic detection of myocardial contours in cine-computed tomographic images.

    PubMed

    Philip, K P; Dove, E L; McPherson, D D; Gotteiner, N L; Vonesh, M J; Stanford, W; Reed, J E; Rumberger, J A; Chandran, K B

    1994-01-01

    Quantitative evaluation of cardiac function from cardiac images requires the identification of the myocardial walls. This generally requires the clinician to view the image and interactively trace the contours. This method is susceptible to great variability that depends on the experience and knowledge of the particular operator tracing the contours. The particular imaging modality that is used may also add tracing difficulties. Cine-computed tomography (cine-CT) is an imaging modality capable of providing high quality cross-sectional images of the heart. CT images, however, are cluttered, i.e., objects that are not of interest, such as the chest wall, liver, stomach, are also visible in the image. To decrease this variability, investigators have developed computer-assisted or near-automatic techniques for tracing these contours. All of these techniques, however, require some operator intervention to confidently identify myocardial borders. The authors present a new algorithm that automatically finds the heart within the chest, and then proceeds to outline (detect) the myocardial contours. Information at each tomographic slice is used to estimate the contours at the next tomographic slice, thus allowing the algorithm to work in near-apical cross-sectional images where the myocardial borders are often difficult to identify. The algorithm does not require operator input and can be used in a batch mode to process large quantities of data. An evaluation and correction phase is included to allow an operator to view the results and selectively correct portions of contours. The authors tested the algorithm by automatically identifying the myocardial borders of 27 cardiac images obtained from three human subjects and quantitatively comparing these automatically determined borders with those traced by an experienced cardiologist.

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

    USGS Publications Warehouse

    Bohling, G.C.; Zhan, X.; Butler, J.J.; 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.

  2. Removal of ring artifacts in computed tomographic imaging using iterative center weighted median filter.

    PubMed

    Sadi, Fazle; Lee, Soo Yeol; Hasan, Md Kamrul

    2010-01-01

    A new iterative center weighted median filter (ICWMF) for ring artifact reduction from the micro-computed tomographic (micro-CT) image is proposed in this paper. The center weight of the median filter is computed based on the characteristic of the ring artifact in the mean curve of the projection data. The filter operates on the deviation of the mean curve to smooth the ring generating peaks and troughs iteratively while preserving the details due to image. A convergence criterion for the iterative algorithm is determined from the distribution of the local deviation computed from the mean curve deviation. The estimate of the mean curve obtained using the ICWMF is used to correct the ring corrupted projection data from which reconstruction gives the ring artifact suppressed micro-CT image. Test results on both the synthetic and real images demonstrate that the ring artifacts can be more effectively suppressed using our method as compared to other ring removal techniques reported in the literature.

  3. Unusual manifestations of craniofacial fibrous dysplasia: clinical, endocrinological and computed tomographic features.

    PubMed

    Daly, B D; Chow, C C; Cockram, C S

    1994-01-01

    Clinical, endocrinological and computed tomographic features of three patients with unusual manifestations or complications of craniofacial involvement of fibrous dysplasia are presented. One patient with polyostotic fibrous dysplasia presented in late pregnancy with acute onset of bilateral optic nerve compression and blindness secondary to a rapidly expanding mass of fibrous dysplasia tissue involving the sphenoid, pituitary and optic chiasm regions. A second patient with polyostotic fibrous dysplasia developed thyrotoxicosis and probable gigantism/acromegaly in keeping with a rare form of McCune-Albright syndrome. Extensive bony distortion of the skull and facial bones by fibrous dysplasia made clinical recognition of these complications more difficult. A third patient had monostotic fibrous dysplasia with marked sclerosis of the sphenoid bone on plain radiographs which mimicked appearances of a meningioma and resulted in a negative craniotomy as computed tomography was not yet available at the time of presentation. Each case demonstrated rare complications of craniofacial fibrous dysplasia and highlighted the wide spectrum of appearances in which it may manifest, often resulting in overlap and diagnostic confusion with other disease processes. The value of computed tomography in assessment is emphasized. PMID:8140010

  4. Seeing is believing: video classification for computed tomographic colonography using multiple-instance learning.

    PubMed

    Wang, Shijun; McKenna, Matthew T; Nguyen, Tan B; Burns, Joseph E; Petrick, Nicholas; Sahiner, Berkman; Summers, Ronald M

    2012-05-01

    In this paper, we present development and testing results for a novel colonic polyp classification method for use as part of a computed tomographic colonography (CTC) computer-aided detection (CAD) system. Inspired by the interpretative methodology of radiologists using 3-D fly-through mode in CTC reading, we have developed an algorithm which utilizes sequences of images (referred to here as videos) for classification of CAD marks. For each CAD mark, we created a video composed of a series of intraluminal, volume-rendered images visualizing the detection from multiple viewpoints. We then framed the video classification question as a multiple-instance learning (MIL) problem. Since a positive (negative) bag may contain negative (positive) instances, which in our case depends on the viewing angles and camera distance to the target, we developed a novel MIL paradigm to accommodate this class of problems. We solved the new MIL problem by maximizing a L2-norm soft margin using semidefinite programming, which can optimize relevant parameters automatically. We tested our method by analyzing a CTC data set obtained from 50 patients from three medical centers. Our proposed method showed significantly better performance compared with several traditional MIL methods. PMID:22552333

  5. Computed tomographic colonography (CTC): Possibilities and limitations of clinical application in colorectal polyps and cancer.

    PubMed

    Heuschmid, Martin; Luz, Oliver; Schaefer, Juergen F; Kopp, Andreas F; Claussen, Claus D; Seemann, Marcus D

    2004-04-01

    Colorectal cancer is the second leading cause of cancer-related deaths in Europe and the United States. Most colorectal cancers develop from adenomatous polyps over a number of years. Early detection of polyps eliminates the risk of subsequent carcinomas. Computed tomographic (CT) colonography is a diagnostic technique detecting colorectal neoplasms. With the introduction of multidetector-row computed tomography (MD-CT), CT colonography (CTC) has gained influence as a new diagnostic tool in early detection of colonic pathologies by acquiring volumetric CT data sets of the abdomen. This volumetric data is analyzed using CTC workstations, which provide an interactive display of 2D and 3D images of the colon. In several studies, CTC revealed a high accuracy (sensitivity/patient: 83-100% and specificity/patient: 93-100%) in detecting pathological colonic changes. Furthermore, CTC is an excellent diagnostic technique for the evaluation of patients with incomplete conventional colonoscopy and allows the assessment of extracolonic abdominal and pelvic organs. In this article, the status of CT colonography as a method of detecting colonic polyps and colorectal carcinomas using single- and multidetector-row CT will be reviewed.

  6. Coronary artery fistula: 64-slice computed tomographic delineation and correlation with multiplane transesophageal echocardiography and surgical findings.

    PubMed

    Joshi, Jonathan K; Beache, Garth M; Slaughter, Mark S; Sobieski, Michael A; Schneider, William; Stoddard, Marcus F

    2012-03-01

    A 49-year-old female who presented with 3 weeks of exertional chest pain had an abnormal mediastinal finding at chest x-ray imaging. Conventional, nongated computed tomography of the chest revealed a "mass" in proximity to the right atrium. 64-slice, cardiac gated computed tomographic coronary angiography, and transesophageal echocardiography delineated the "mass" as a coronary artery fistula structure. The fistula originated from the left main as a tubular vessel that continued into an aneurysmal sac-like cavity that emptied into the superior vena cava near the right atrium. Computed tomographic coronary angiography showed otherwise normal coronary arteries. Findings were ultimately confirmed at cardiac catheterization. Coronary steal was clinically diagnosed and she underwent surgical ligation and resection of the fistula and aneurysm. Her subsequent course was uncomplicated.

  7. 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

  8. 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

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

    PubMed

    Alsulaiman, Thamer; 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

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

    PubMed

    Alsulaiman, Thamer; 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.

  11. 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

  12. 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.

  13. Hyperspectral Computed Tomographic Imaging Spectroscopy of Vascular Oxygen Gradients in the Rabbit Retina In Vivo

    PubMed Central

    Kashani, Amir H.; Kirkman, Erlinda; Martin, Gabriel; Humayun, Mark S.

    2011-01-01

    Diagnosis of retinal vascular diseases depends on ophthalmoscopic findings that most often occur after severe visual loss (as in vein occlusions) or chronic changes that are irreversible (as in diabetic retinopathy). Despite recent advances, diagnostic imaging currently reveals very little about the vascular function and local oxygen delivery. One potentially useful measure of vascular function is measurement of hemoglobin oxygen content. In this paper, we demonstrate a novel method of accurately, rapidly and easily measuring oxygen saturation within retinal vessels using in vivo imaging spectroscopy. This method uses a commercially available fundus camera coupled to two-dimensional diffracting optics that scatter the incident light onto a focal plane array in a calibrated pattern. Computed tomographic algorithms are used to reconstruct the diffracted spectral patterns into wavelength components of the original image. In this paper the spectral components of oxy- and deoxyhemoglobin are analyzed from the vessels within the image. Up to 76 spectral measurements can be made in only a few milliseconds and used to quantify the oxygen saturation within the retinal vessels over a 10–15 degree field. The method described here can acquire 10-fold more spectral data in much less time than conventional oximetry systems (while utilizing the commonly accepted fundus camera platform). Application of this method to animal models of retinal vascular disease and clinical subjects will provide useful and novel information about retinal vascular disease and physiology. PMID:21931729

  14. 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

  15. 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.

  16. 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.

  17. [¹³N]Ammonia positron emission tomographic/computed tomographic imaging targeting glutamine synthetase expression in prostate cancer.

    PubMed

    Shi, Xinchong; Zhang, Xiangsong; Yi, Chang; Liu, Yubo; He, Qiao

    2014-01-01

    The purpose of this study was to investigate the expression of glutamine synthetase (GS) in prostate cancer (PCa) and the utility of [¹³N]ammonia positron emission tomography/computed tomography (PET/CT) in the imaging of PCa. The uptake ratio of [¹³N]ammonia and the expression of GS in PC3 and DU145 cells was measured. Thirty-four patients with suspected PCa underwent [¹³N]ammonia PET/CT imaging, and immunohistochemistry staining of GS was performed. The uptake of [¹³N]ammonia in PC3 and DU145 cells elevated along with the decrease in glutamine in medium. The expression of GS messenger ribonucleic acid and protein also increased when glutamine was deprived. In biopsy samples, the GS expression scores were significantly higher in PCa tissue than in benign tissues (p < .001), and there was a positive correlation between the maximum GS expression scores and Gleason scores (Spearman r  =  .52). In 34 patients, [¹³N]ammonia uptake in PCa segments was significantly higher than that in benign segments (p ≤ .01), and there was a weak correlation between GS expression scores and the uptake of [¹³N]ammonia (Spearman r  =  .47). The expression of GS in PCa cells upregulated along with the deprivation of glutamine. GS is the main reason for the uptake of [¹³N]ammonia, and [¹³N]ammonia is a useful tracer for PCa imaging.

  18. 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

  19. 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.

  20. Coronary Computed Tomographic Angiography Does Not Accurately Predict the Need of Coronary Revascularization in Patients with Stable Angina

    PubMed Central

    Hong, Sung-Jin; Her, Ae-Young; Suh, Yongsung; Won, Hoyoun; Cho, Deok-Kyu; Cho, Yun-Hyeong; Yoon, Young-Won; Lee, Kyounghoon; Kang, Woong Chol; Kim, Yong Hoon; Kim, Sang-Wook; Shin, Dong-Ho; Kim, Jung-Sun; Kim, Byeong-Keuk; Ko, Young-Guk; Choi, Byoung-Wook; Choi, Donghoon; Jang, Yangsoo

    2016-01-01

    Purpose To evaluate the ability of coronary computed tomographic angiography (CCTA) to predict the need of coronary revascularization in symptomatic patients with stable angina who were referred to a cardiac catheterization laboratory for coronary revascularization. Materials and Methods Pre-angiography CCTA findings were analyzed in 1846 consecutive symptomatic patients with stable angina, who were referred to a cardiac catheterization laboratory at six hospitals and were potential candidates for coronary revascularization between July 2011 and December 2013. The number of patients requiring revascularization was determined based on the severity of coronary stenosis as assessed by CCTA. This was compared to the actual number of revascularization procedures performed in the cardiac catheterization laboratory. Results Based on CCTA findings, coronary revascularization was indicated in 877 (48%) and not indicated in 969 (52%) patients. Of the 877 patients indicated for revascularization by CCTA, only 600 (68%) underwent the procedure, whereas 285 (29%) of the 969 patients not indicated for revascularization, as assessed by CCTA, underwent the procedure. When the coronary arteries were divided into 15 segments using the American Heart Association coronary tree model, the sensitivity, specificity, positive predictive value, and negative predictive value of CCTA for therapeutic decision making on a per-segment analysis were 42%, 96%, 40%, and 96%, respectively. Conclusion CCTA-based assessment of coronary stenosis severity does not sufficiently differentiate between coronary segments requiring revascularization versus those not requiring revascularization. Conventional coronary angiography should be considered to determine the need of revascularization in symptomatic patients with stable angina. PMID:27401637

  1. Tomographic measurement of temperature change in phantoms of the human body by chirp radar-type microwave computed tomography.

    PubMed

    Miyakawa, M

    1993-07-01

    The chirp radar-type microwave computed tomograph (CT) measures the temperature change in a human body noninvasively. The paper examines its feasibility. A chirp pulse signal between 1 and 2 GHz is radiated from the transmitting antenna to the phantom. The transmitted waves are detected by the receiving antenna, which is placed on the opposite side of the object, and the beat signal between the incident wave and the transmitted wave is produced by the mixer. By spectral analysis of the beat signal, only those signals transmitted on the straight line between the transmitting antenna and the receiving antenna are discriminated from multipath signals. The microwave tomogram can therefore be reconstructed easily using the conventional algorithms for an X-ray CT image. The microwave CT can use the chirp signal to remove the influence of multipath signals caused by diffraction and reflection. The imaging of dielectric materials with complicated structures is thus possible. The experimental results using phantoms show that the spatial resolution of this microwave CT is about 10 mm and that a two-dimensional distribution of temperature change can be measured.

  2. 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

  3. 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.

  4. Computed tomographic findings of environmental asbestos-related malignant pleural mesothelioma.

    PubMed

    Yilmaz, U M; Utkaner, G; Yalniz, E; Kumcuoglu, Z

    1998-03-01

    Malignant pleural mesothelioma (MPM) is not an infrequent fatal neoplasm. It is endemically present in some regions of Turkey due to its aetiological relationship to exposure to environmental fibrous minerals. The aim of this study was to determine the thorax computed tomographic (CT) features of environmental asbestos-related MPM. In this study, we examined retrospectively the CT scans of 46 untreated patients with pathological diagnosis of environmental asbestos-related MPM among 151 patients with malignant pleural mesothelioma in the Izmir Chest Disease and Surgery Hospital. The CT scans were interpreted by consultation of four observers. Malignant pleural mesothelioma was unilateral in 45 (97.2%) of the patients. Pleural effusions were found in 42 (91%) of the patients, pleural calcifications in 12 (26%), contracted hemithorax in 14 (30%), interlobar fissure involvement in 25 (54%) and mediastinal pleural involvement in 26 (57%). A contracted hemithorax was significantly correlated with pleural rind configuration. Pleural thickenings were found in 45 (99%) of the patients. Pleural thickenings were in the form of nodularity in 10 (22%) cases, regular in 12 (27%) cases, as a focal mass in 3 (7%) cases and as a pleural rind in 20 (44%) cases. Pleural thickening was greater than 1 cm in 32 (71%) cases. The most common CT findings in our series were unilateral circumferential pleural thickening, nodular pleural thickening, pleural thickening greater than 1 cm and mediastinal pleural involvement. Generally, pleural effusion was accompanied by this. There was interlobar fissure involvement in half of the patients. There was no pathognomonic CT finding in environmental asbestos-related MPM. But CT was useful in suggesting the diagnosis of malignant pleural disease in the cases with MPM.

  5. 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

  6. Prevalence of coronary atherosclerosis in an Asian population: findings from coronary computed tomographic angiography.

    PubMed

    Park, Gyung-Min; Yun, Sung-Cheol; Cho, Young-Rak; Gil, Eun Ha; Her, Sung Ho; Kim, Seon Ha; Jo, Min-Woo; Lee, Moo Song; Lee, Seung-Whan; Kim, Young-Hak; Yang, Dong Hyun; Kang, Joon-Won; Lim, Tae-Hwan; Kim, Beom-Jun; Koh, Jung-Min; Kim, Hong-Kyu; Choe, Jaewon; Park, Seong-Wook; Park, Seung-Jung

    2015-03-01

    We sought to estimate the prevalence of coronary atherosclerosis by coronary computed tomographic angiography (CCTA) and to identify risk factors attributable to the development of coronary atherosclerosis in an asymptomatic Asian population. We analyzed 6,311 consecutive asymptomatic individuals aged 40 and older with no prior history of coronary artery disease (CAD) who voluntarily underwent CCTA evaluation as part of a general health examination. The mean age of study participants was 54.7 ± 7.4 years, and 4,594 (72.8%) were male. After age and gender adjustment using the population census of the National Statistical Office, the prevalence of plaque was 40.5% [95% confidence interval (CI) 38.1-42.9], and significant CAD (diameter stenosis ≥50%) was observed in 9.0% (95% CI 7.7-10.2). Individuals with significant CAD were significantly older than those without (59.2 ± 8.8 vs. 54.0 ± 7.1 years, p < 0.001). Compared with individuals with no cardiovascular risk factors, there was a higher prevalence of significant CAD in individuals with diabetes mellitus [standardized rate ratio (SRR) 2.66; 95% CI 1.93-3.68; p < 0.001], hypertension (SRR 2.24; 95% CI 1.69-2.97; p < 0.001), or hyperlipidemia (SRR 1.65; 95% CI 1.25-2.17; p < 0.001). There was also a greater prevalence of significant CAD in individuals with an intermediate or high Framingham risk score (SRR 5.91; 95% CI 2.34-14.95; p < 0.001) or a high atherosclerotic cardiovascular disease risk score (SRR 8.04; 95% CI 3.04-21.23; p < 0.001). The prevalence of coronary atherosclerosis in this Asian population was not negligible and was associated with known cardiovascular risk factors and high-risk individuals.

  7. A preoperative mathematic model for computed tomographic guided microwave ablation treatment of hepatic dome tumors

    PubMed Central

    Yang, Bin; Xue, Jing-Bing; Mo, Zhi-Qiang; Zhong, Zhi-Hui; Zhang, Tao; Zhang, Fu-Jun; Fan, Wei-Jun

    2016-01-01

    Purpose This study sought to prospectively evaluate the feasibility and safety of a preoperative mathematic model for computed tomographic(CT) guided microwave(MW) ablation treatment of hepatic dome tumors. Methods This mathematic model was a regular cylinder quantifying appropriate puncture routes from the bottom up. A total of 103 patients with hepatic dome tumors were enrolled and randomly divided into 2 groups based on whether this model was used or not: Group A (using the model; n = 43) versus Group B (not using the model; n = 60). All tumors were treated by CT-guided MW ablation and follow-up contrast CT were reviewed. Results The average number of times for successful puncture, average ablation time, and incidence of right shoulder pain were less in Group A than Group B (1.4 vs. 2.5, P = 0.001; 8.8 vs. 11.1 minutes, P = 0.003; and 4.7% vs. 20%, P = 0.039). The technical success rate was higher in Group A than Group B (97.7% vs. 85.0%, P = 0.032). There were no significant differences between the two groups in primary and secondary technique efficacy rates (97.7% vs. 88.3%, P = 0.081; 90.0% vs. 72.7%, P = 0.314). No major complications occurred in both groups. Conclusion The mathematic model of regular cylinder is feasible and safe for CT-guided MW ablation in treating hepatic dome tumors. PMID:27028994

  8. 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.

  9. 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.

  10. Spinal computed tomography and computed tomographic metrizamide myelography in the early diagnosis of metastatic disease

    SciTech Connect

    O'Rourke, T.; George, C.B.; Redmond, J. 3d.; Davidson, H.; Cornett, P.; Fill, W.L.; Spring, D.B.; Sobel, D.; Dabe, I.B.; Karl, R.D. Jr.

    1986-04-01

    New lesions were shown by Tc99m bone scans to have developed in sixty patients with known metastatic cancer or high-risk primary cancer and normal neurologic examinations; they were further evaluated with plain radiographs, spinal computed tomography (CT), and CT myelography (CT-M) according to an algorithm. Three groups were identified based on plain radiographs: group 1 (normal radiograph), group 2 (compression fracture as indicated by radiograph), group 3 (evidence of metastasis as indicated by radiograph). In group 1 (n = 18), spinal CT revealed that 33% of the patients had benign disease and 67%, metastases; epidural compression was seen in 25% of the patients with metastasis as indicated by CT-M. In group 2 (n = 26), CT-M disclosed that 38% had a benign compression fracture and 62% had metastases and that 63% of the patients with metastases had an epidural compression. In group 3 (n = 16), spinal CT revealed that 15 patients had metastases (one patient had benign disease). Epidural cord compression was seen in 47% of the patients with metastatic disease. In all groups, the presence of cortical bone discontinuity around the neural canal (seen in 31 patients) was highly associated with epidural compression (seen in 20 patients). Our approach allowed the early and accurate diagnosis of spinal metastasis and epidural tumor as well as the diagnosis of benign disease and was useful in planning optimal local therapy.

  11. Three-dimensional cephalometry: a method for the identification and for the orientation of the skull after cone-bean computed tomographic scan.

    PubMed

    Frongia, Gianluigi; Bracco, Pietro; Piancino, Maria Grazia

    2013-05-01

    The aims of this work were (1) to describe a method to identify new skeletal landmarks useful to define the reference system to orient the skull in a new position after cone-bean computed tomographic scan and (2) to demonstrate the reliability of this new method.Ten orthognathic patients (5 male, 5 female; mean [SD] age, 18.9 [1.2] years) underwent the cone-bean computed tomographic scan before surgery. Seven 3-dimensional skeletal measurements derived from 4 skeletal point of construction (C) (right, left, and median orbital C, and sella C) have been used for this study. Reliability has been calculated using Pearson correlation coefficient tests.Intraobserver reliability was 0.9999 for operator A (T1-T2) and 0.9999 for operator B (T1-T2); interobserver reliability was 0.9999 between the first (T1-T1) measurement and 0.9999 between the second (T2-T2).The original method is able to reduce the variability of landmark identification due to the variability of the human anatomy and the influence of the human error in cephalometric analysis. The innovation of this new method is the real possibility to use the anatomical structures in a 3-dimensional way, enhancing the reliability of the reference points.

  12. 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

  13. 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

  14. Resolution analysis of tomographic slug test head data: Two-dimensional radial case

    NASA Astrophysics Data System (ADS)

    Paradis, Daniel; Gloaguen, Erwan; Lefebvre, René; Giroux, Bernard

    2015-04-01

    Hydraulic tomography inverse problems, which are solved to estimate aquifer hydraulic properties between wells, are known to be ill-conditioned and a priori information is often added to regularize numerical inversion of head data. Because both head data and a priori information have effects on the inversed solution, assessing the meaningful information contained in head data alone is required to ensure comprehensive interpretation of inverse solutions, whether they are regularized or not. This study thus aims to assess the amount of information contained in tomographic slug tests head data to resolve heterogeneity in Kh, Kv/Kh, and Ss. Therefore, a resolution analysis based on truncated singular value decomposition of the sensitivity matrix with a noise level representative of field measurements is applied using synthetic data reflecting a known littoral aquifer. As an approximation of the hydraulic behavior of a real aquifer system, synthetic tomographic experiments and associated sensitivity matrices are generated using a radial flow model accounting for wellbore storage to simulate slug tests in a plane encompassing a stressed well and an observation well. Although fine-scale resolution of heterogeneities is limited by the diffusive nature of the groundwater flow equations, inversion of tomographic slug tests head data holds the potential to uniquely resolve coarse-scale heterogeneity in Kh, Kv/Kh, and Ss, as inscribed in the resolution matrix. This implies that tomographic head data can provide key information on aquifer heterogeneity and anisotropy, but that fine-scale information must be supplied by a priori information to obtain finer details.

  15. 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

  16. Tuning the cache memory usage in tomographic reconstruction on standard computers with Advanced Vector eXtensions (AVX).

    PubMed

    Agulleiro, Jose-Ignacio; Fernandez, Jose-Jesus

    2015-06-01

    Cache blocking is a technique widely used in scientific computing to minimize the exchange of information with main memory by reusing the data kept in cache memory. In tomographic reconstruction on standard computers using vector instructions, cache blocking turns out to be central to optimize performance. To this end, sinograms of the tilt-series and slices of the volumes to be reconstructed have to be divided into small blocks that fit into the different levels of cache memory. The code is then reorganized so as to operate with a block as much as possible before proceeding with another one. This data article is related to the research article titled Tomo3D 2.0 - Exploitation of Advanced Vector eXtensions (AVX) for 3D reconstruction (Agulleiro and Fernandez, 2015) [1]. Here we present data of a thorough study of the performance of tomographic reconstruction by varying cache block sizes, which allows derivation of expressions for their automatic quasi-optimal tuning. PMID:26217710

  17. Tomographic Analysis of the West Bohemia Seismic Zone

    NASA Astrophysics Data System (ADS)

    Alexandrakis, Catherine; Calo, Marco; Vavrycuk, Vaclav

    2013-04-01

    The West Bohemia Seismic Zone is located on the border between Czech Republic and Germany. This region has several areas which experience periodic microseismic swarm activity. The installation of the West Bohemia Seismic Network (WEBNET) has allowed constant monitoring of the town Nový Kostel and surrounding area. Nový Kostel is one of the most active areas. Larger swarms, such as those in 1997, 2000, 2007, 2008 and 2011, have been studied in terms of source mechanisms and swarm characteristics. Despite these analyses, questions remain regarding the subsurface structure in and around the focal zone, and the swarm trigger. In this study, we investigate the seismic velocity structures within and around Nový Kostel using double-difference tomography and Weighted Average Model (WAM) post-processing analysis. To do this, we calculate a set of velocity models using a range of reasonable starting parameterizations that are compatible with the experimental information used. The WAM analysis produces a single averaged model and calculates the weighted standard deviation at each inversion node. By averaging the models together, bias and artefacts from the starting models are reduced. In addition, the weighted standard deviation is used to assess the averaged Vp and Vs models for stability and resolution. The full control on the reliability of the Vp and Vs models allows us to also calculate a Vp/Vs model by directly dividing the P and S seismic velocities. Initial results using a subset of the 2008 swarm indicated a low-Vp/Vs layer overlaying the focal zone, and high Vp and Vp/Vs values along the fault zone. This hinted towards a low-permeability layer acting as a fluid trap, and potentially triggering the swarms. Here, we further the investigation by using the full WEBNET catalog from 1991-2011. We invert the full catalog of P and S arrival times along with detailed inversions of individual swarms to produce a structural model of the Nový Kostel area.

  18. 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.

  19. [Healing of experimental defect in a long bone after implantation of "CollapAn" osteoplastic material in its cavity (computed tomographic study)].

    PubMed

    Kopen'kov, A V

    2015-01-01

    The dynamics of biodegradation of "CollapAn" osteoplastic material was studied after its implantation into the defect of the femoral diaphysis in 30 rats. Computed tomographic analysis of the healing of bone defects was conducted with the determination of the optical density of bone tissue in Hounsfield units. Since Day 30 of the experiment, the appearance and further progress of the radiographic signs of bone tissue neoformation and maturation were noted exactly along the contours of osteoplastic material, together with the gradual disappearance of the defect from the side of bone cortical layer and simultaneous increase of the optical density of the intermediary and endosteal part of the regenerate. At Day 120, regenerate optical density exceeded the absolute optical density of the parent bone; simultaneously, during this period no full recovery of the original shape of the bone took place, while parent bone rarefication was identified during all the periods of observation.

  20. Asymmetric Genome Organization in an RNA Virus Revealed via Graph-Theoretical Analysis of Tomographic Data

    PubMed Central

    Geraets, James A.; Dykeman, Eric C.; Stockley, Peter G.; Ranson, Neil A.; Twarock, Reidun

    2015-01-01

    Cryo-electron microscopy permits 3-D structures of viral pathogens to be determined in remarkable detail. In particular, the protein containers encapsulating viral genomes have been determined to high resolution using symmetry averaging techniques that exploit the icosahedral architecture seen in many viruses. By contrast, structure determination of asymmetric components remains a challenge, and novel analysis methods are required to reveal such features and characterize their functional roles during infection. Motivated by the important, cooperative roles of viral genomes in the assembly of single-stranded RNA viruses, we have developed a new analysis method that reveals the asymmetric structural organization of viral genomes in proximity to the capsid in such viruses. The method uses geometric constraints on genome organization, formulated based on knowledge of icosahedrally-averaged reconstructions and the roles of the RNA-capsid protein contacts, to analyse cryo-electron tomographic data. We apply this method to the low-resolution tomographic data of a model virus and infer the unique asymmetric organization of its genome in contact with the protein shell of the capsid. This opens unprecedented opportunities to analyse viral genomes, revealing conserved structural features and mechanisms that can be targeted in antiviral drug design. PMID:25793998

  1. 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

  2. Computed-tomographic density measurement of supersonic flow field by colored-grid background oriented schlieren (CGBOS) technique

    NASA Astrophysics Data System (ADS)

    Ota, Masanori; Hamada, Kenta; Kato, Hiroko; Maeno, Kazuo

    2011-10-01

    The background oriented schlieren (BOS) technique is one of the visualization techniques that enable the quantitative measurement of density information in the flow field with very simple experimental setup. The principle of BOS is similar to the conventional schlieren technique, which exploits the bending of light caused by refractive index change corresponding to density change in the medium and both techniques are sensible to density gradient. In this report we propose colored-grid background oriented schlieren (CGBOS) technique. The experiments were carried out in a supersonic wind tunnel of test section size 0.6 × 0.6 m2 at JAXA-ISAS. A colored-grid pattern was used as background image and density gradient in vertical and horizontal direction was obtained. Computed tomographic reconstructions of 3D density information of the supersonic flow field around an asymmetric body from multi-directional CGBOS images were examined.

  3. 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.

  4. 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

  5. Clinical and Radiographic Findings and Usefulness of Computed Tomographic Assessment in Two Children with Regional Odontodysplasia

    PubMed Central

    Matsuyama, Junko; Tanaka, Ray; Iizawa, Futabako; Sano, Tomiko; Kinoshita-Kawano, Shoko; Hayashi-Sakai, Sachiko; Mitomi, Tomoe

    2014-01-01

    Regional odontodysplasia is a rare, severe, and nonhereditary developmental disorder in tooth formation and involves epithelial and mesenchymal-derived dental tissue. On radiographs, affected teeth have an abnormal morphology, a hypoplastic crown, and only a faint outline of hard tissue, a condition termed “ghost teeth.” We report clinical and radiographic findings from two children with regional odontodysplasia. Using computed tomography (CT), we calculated attenuation coefficients (i.e., Hounsfield units) for affected teeth and assessed the condition of dental follicles. To measure density, regions of interest were delimited and CT values were calculated. In our two patients, the CT values for enamel were lower in affected teeth than in sound teeth, while CT values for dentin were similar for affected and sound teeth. The average CT value for dental follicles in affected teeth was about 65 to 120, which suggests that dense fibrous connective tissues or hard tissue-like structures might be present in dental follicles. Analysis of CT values may be quite useful in the diagnosis and treatment of regional odontodysplasia. PMID:25250179

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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

  12. Measurement of cochlea to facial nerve canal with thin-section computed tomographic image.

    PubMed

    Jiang, Ying; Liu, Xiangliang; Yao, Jihang; Tian, Yong; Xia, Changli; Li, Youqiong; Fu, Yan; Luo, Qi

    2013-03-01

    Facial nerve (FN) paralysis is a rare but devastating complication of cochlear implant surgery. This study aimed to measure the cupula of the cochlea to the tympanic segment of the FN canal, cupula of the cochlea to the mastoid segment of the FN canal, and the geniculate ganglion to provide a more secure and accurate orientation of the FN canal and to facilitate operation on the cochlea by avoiding potential damage to FN. Using computed tomography, we scanned skulls of 120 volunteers who suffer no cases of skull base lesions. Multiplane reconstruction images were prepared with high-resolution computed tomography. Preoperative evaluation of the FN anatomy within the temporal bone by high-resolution computed tomography helps in minimizing surgical trauma to the nerve, and these results can help guide clinical surgery on the cochlea.

  13. 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

  14. 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

  15. 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

  16. The challenge of coronary calcium on coronary computed tomographic angiography (CCTA) scans: effect on interpretation and possible solutions.

    PubMed

    Andrew, Makmur; John, Hoe

    2015-12-01

    Coronary calcium seen on coronary computed tomographic angiography (CCTA) scans is a common diagnostic challenge which can make interpretation difficult. It is the most common cause of false positive (FP) results from CCTA compared with invasive coronary angiography (ICA), and affects the positive predictive results. At the same time, coronary calcium can result in false negative (FN) results, and this again can affect the reported diagnostic accuracy of CCTA, as the high negative predictive value of CCTA compared to ICA is one of its strengths. This paper reviews the reasons that coronary calcium can cause FP and FN results, and the effects of the morphologies and sizes of the calcified plaques, with particular regard to their relationship with the visualization of the contrast-filled lumen of the coronary artery. Some possible solutions to overcome the limitations of reading CCTA scans with calcified plaques also are discussed, with a view to improving the accuracy of interpreting and reporting CCTA scans; these solutions include using the degree of residual visible contrast-filled lumen to help assess the likelihood of significant associated coronary stenosis, and applying newer technical developments such as dual-energy imaging and volume calcium subtraction.

  17. 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.

  18. High performance computing for a 3-D optical diffraction tomographic application in fluid velocimetry.

    PubMed

    Lobera, Julia; Ortega, Gloria; García, Inmaculada; Arroyo, María del Pilar; Garzón, Ester M

    2015-02-23

    Optical Diffraction Tomography has been recently introduced in fluid velocimetry to provide three dimensional information of seeding particle locations. In general, image reconstruction methods at visible wavelengths have to account for diffraction. Linear approximation has been used for three-dimensional image reconstruction, but a non-linear and iterative reconstruction method is required when multiple scattering is not negligible. Non-linear methods require the solution of the Helmholtz equation, computationally highly demanding due to the size of the problem. The present work shows the results of a non-linear method customized for spherical particle location using GPU computing and a made-to-measure storing format.

  19. Computed tomographic evaluation of a bronchogenic cyst in a German shepherd dog.

    PubMed

    Gadbois, Julie; Blond, Laurent; Lapointe, Catherine; Collard, Fabien

    2012-01-01

    A German shepherd dog was referred for further evaluation of a cavitary pulmonary lesion. Computed tomography identified a well-defined rounded radiolucent area in the left cranial lung lobe in continuity with the bronchial lumen. These findings were consistent with a bronchogenic cyst. PMID:22753971

  20. [Computer tomographic demonstration of haematomas in the pelvis and abdomen (author's transl)].

    PubMed

    Gürtler, K F; Buurman, R; Erbe, W

    1979-11-01

    Retro- and intra-peritoneal haematomas have been demonstrated in 19 patients by computer tomography. Absorption values varied from 0 to 65 Hounsfield units. Absorption values are high shortly after the trauma, but fall during the following days and weeks because of absorption and enzymatic chances of the haemaglobin and protein. A diagnosis can only be made with a knowledge of the clinical background. Tumours, abscesses and cysts must be considered in the differential diagnosis. Unlike conventional radiography, haematomas can be directly demonstrated by computer tomography. Angiography may demonstrate the point of bleeding when there is no haematoma, or if an haematoma fails to develop because bleeding is taking place into a hollow organ or a duct.

  1. Computed tomographic findings in a case of renal vein thrombosis with nephrotic syndrome.

    PubMed

    Adler, J; Greweldinger, J; Hallac, R; Frier, S

    1981-01-01

    Renal vein thrombosis is a complication of the nephrotic syndrome presumably related to compression of renal veins by edematous parenchyma and a concomitant hypercoagulable state. The diagnosis has been made by demonstrating marked widening of the left renal vein as it crosses horizontally anterior to the aorta on computed tomography. Inferior venacavography confirmed the presence of thrombosis within the vessels. CT is suggested as a method for noninvasive imaging of the renal veins which might eliminate the need for venography.

  2. [Diprosopus triophthalmus. From ancient terracotta sculptures to spiral computer tomographic reconstruction].

    PubMed

    Sokiranski, R; Pirsig, W; Nerlich, A

    2005-03-01

    A still-born male fetus from the 19th century, fixed in formalin and presenting as diprosopia triophthalmica, was analysed by helical computer tomography and virtually reconstructed without damage. This rare, incomplete, symmetrical duplication of the face on a single head with three eyes, two noses and two mouths develops in the first 3 weeks of gestation and is a subset of the category of conjoined twins with unknown underlying etiology. Spiral computer tomography of fixed tissue demonstrated in the more than 100 year old specimen that virtual reconstruction can be performed in nearly the same way as in patients (contrast medium application not possible). The radiological reconstruction of the Munich fetus, here confined to head and neck data, is the basis for comparison with a number of imaging procedures of the last 3000 years. Starting with some Neolithic Mesoamerican ceramics, the "Pretty Ladies of Tlatilco", diprosopia triophthalmica was also depicted on engravings of the 16th and 17th century A.D. by artists as well as by the anatomist Soemmering and his engraver Berndt in the 18th century. Our modern spiral computer tomography confirms the ability of our ancestors to depict diprosopia triophthalmica in paintings and sculptures with a high level of natural precision.

  3. 3D computed tomographic evaluation of the upper airway space of patients undergoing mandibular distraction osteogenesis for micrognathia.

    PubMed

    Bianchi, A; Betti, E; Badiali, G; Ricotta, F; Marchetti, C; Tarsitano, A

    2015-10-01

    Mandibular distraction osteogenesis (MDO) is currently an accepted method of treatment for patients requiring reconstruction of hypoplastic mandibles. To date one of the unsolved problems is how to assess the quantitative increase of mandible length needed to achieve a significant change in the volume of the posterior airway space (PAS) in children with mandibular micrognathia following distraction osteogenesis. The purpose of this study is to present quantitative volumetric evaluation of PAS in young patients having distraction osteogenesis for micrognathia using 3D-CT data sets and compare it with pre-operative situation. In this observational retrospective study, we report our experience in five consecutive patients who underwent MDO in an attempt to relieve severe upper airway obstruction. Each patient was evaluated before treatment (T0) and at the end of distraction procedure (T1) with computer tomography (CT) in axial, coronal, and sagittal planes and three-dimensional CT of the facial bones and upper airway. Using parameters to extract only data within anatomic constraints, a digital set of the edited upper airway volume was obtained. The volume determination was used for volumetric qualification of upper airway. The computed tomographic digital data were used to evaluate the upper airway volumes both pre-distraction and post-distraction. The mean length of distraction was 23 mm. Quantitative assessment of upper airway volume before and after distraction demonstrated increased volumes ranging from 84% to 3,087% with a mean of 536%. In conclusion, our study seems to show that DO can significantly increase the volume of the PAS in patients with upper airway obstruction following micrognathia, by an average of 5 times. Furthermore, the worse is the starting volume, the greater the increase in PAS to equal distraction.

  4. Complementary roles of radionuclide and computed tomographic imaging in evaluating trauma.

    PubMed

    Berg, B C

    1983-04-01

    For 6 consecutive months all triage acceptable emergency room patients at the St. Francis Medical Center with blunt or penetrating trauma involving the abdomen were included in this review. Computed tomography and radionuclide imaging of the abdomen and urinary tract was performed in addition to the usually indicated diagnostic procedures. In our hospital the Radiology Department is adjacent to the Emergency Department. Close cooperation of the trauma team, the imaging physician and the technologists, has provided a stable, reproducible pattern in the performance and evaluation of nuclear medicine and radiographic techniques. Teleradiologic techniques of image transmission over the telephone lines permits immediate availability of the expertise of the radiologist. This correlation has provided an opportunity for improving patient care and refining our protocol in the care and management of the acutely traumatized patient. One-hundred-twenty-seven patients classed as acute trauma cases were processed during those 6 mo. Forty-two of these patients were not included in this study. They were triaged as immediate surgical emergencies, had incurred injury limited to the head, extremities or thorax, or were not injured sufficiently to require the special care of the designated trauma team. The 85 patients in this study included 56 males and 29 females. The patient age ranged from 3- to 71-yr-of-age. The median age was 29.3 yr. The author feels the findings in this evaluation of the complementary roles of radionuclide imaging and computed tomography should be of value to others in the formulation of their acute trauma care protocol. Nuclear medicine techniques retain an important role in the diagnosis of several sequelae of head trauma. Sensitivity and accuracy for detection of subdural hematoma are not as high as those of transmission computed tomography even if proper techniques are employed. Other important applications, however, include the diagnosis of normal pressure

  5. Computed tomographical (CT) anatomy of the thoracoabdominal cavity of the male turkey (Meleagris gallopavo).

    PubMed

    Petnehazy, O; Benczik, J; Takacs, I; Petrasi, Zs; Süto, Z; Horn, P; Repa, I

    2012-02-01

    In the present work, our goal was to match high-resolution computed tomography (CT) scans with cross-sectional anatomical pictures of the turkey (Meleagris gallopavo). Two male BUT 6 (a commercial line) turkeys were used. CT scans with 1 mm slice thickness were performed. The images covered the trunk from the level of the 9th cervical vertebra to the end of the coccyx. The anatomical sections and the CT scans were matched, and the important structures were identified and labelled on the corresponding pictures. The aim of this study was to create a reference for evaluating CT scans of avian species.

  6. [Computed tomographic diagnosis of pre- and paravertebral masses in the thorax and retroperitoneum].

    PubMed

    Hermanutz, K D

    1984-06-01

    CT is the method of choice in the diagnostic identification and clarification of prevertebral and paravertebral space-occupying growths before initiating invasive methods of diagnosis and before surgery. CT supplies decisive information by means of the transversal tomography, which is free from overlapping, and enables determination of relative densities. A most important feature is the safe exclusion of any aortoilacal aneurysm via differential diagnosis. The possibilities and limitations of computed tomography are discussed on the basis of several examples, namely, a lateral intrathoracic meningocele, a mediastinal bronchogenic cyst, a retroperitoneal fibrosis, lymph node metastases and hypostatic abscesses.

  7. 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.

  8. Liver Function After Irradiation Based on Computed Tomographic Portal Vein Perfusion Imaging

    SciTech Connect

    Cao Yue Pan, Charlie; Balter, James M.; Platt, Joel F.; Francis, Isaac R.; Knol, James A.; Normolle, Daniel; Ben-Josef, Edgar; Haken, Randall K. ten; Lawrence, Theodore S.

    2008-01-01

    Purpose: To determine whether individual and regional liver sensitivity to radiation could be assessed by measuring liver perfusion during a course of treatment using dynamic contrast-enhanced computed tomography scanning. Methods and Materials: Patients with intrahepatic cancer undergoing conformal radiotherapy underwent dynamic contrast-enhanced computed tomography (to measure perfusion distribution) and an indocyanine extraction study (to measure liver function) before, during, and 1 month after treatment. We hoped to determine whether the residual functioning liver (i.e., those regions showing portal vein perfusion) could be used to predict overall liver function after irradiation. Results: Radiation doses from 45 to 84 Gy resulted in undetectable regional portal vein perfusion 1 month after treatment. The volume of each liver with undetectable portal vein perfusion ranged from 0 to 39% and depended both on the patient's sensitivity and on dose distribution. There was a significant correlation between indocyanine green clearance and the mean of the estimated portal vein perfusion in the functional liver parenchyma (p < 0.001). Conclusion: This study reveals substantial individual variability in the sensitivity of the liver to irradiation. In addition, these findings suggest that hepatic perfusion imaging may be a marker for liver function and has the potential to be a tool for individualizing therapy.

  9. Body position changes redistribute lung computed-tomographic density in patients with acute respiratory failure.

    PubMed

    Gattinoni, L; Pelosi, P; Vitale, G; Pesenti, A; D'Andrea, L; Mascheroni, D

    1991-01-01

    Ten patients with parenchymal acute respiratory failure (ARF) underwent computed tomography (CT) scans while in the supine and prone positions. At equal levels of positive end-expiratory pressure, the authors measured the changes of CT density in dorsal and ventral basilar lung regions induced by the change of position as well as alterations of gas exchange. The level of venous admixture did not change with body position. The CT scan image of each lung was fractionated into ten levels from dorsal to ventral, each constituting 10% of the lung height. After measuring each lung fraction, the volume, the average CT number, its frequency distribution, and the expected normal value, we computed the lung tissue mass, the excess tissue mass, and the fraction of normally inflated tissue (excess tissue mass = amount of "tissue," which includes edema, cells, and blood in excess of the expected normal value). We also estimated the superimposed hydrostatic pressure on each lung region. We found that the excess lung tissue mass is independent of position. However, in patients in the supine position, lung CT density increased and regional inflation decreased from ventral to dorsal, suggesting progressive deflation of gas-containing alveoli along the gravity gradient. A similar ventral-dorsal deflation pattern occurred within 10 min in patients in the prone position. We conclude that the lung in patients with ARF behaves like an elastic body with a diffusely increased mass; dependent lung regions are compressed by the pressure of overlying structures.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. 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.

  11. High-resolution computed tomographic appearance of the intrasellar contents in women of childbearing age

    SciTech Connect

    Swartz, J.D.; Russell, K.B.; Basile, B.A.; O'Donnell, P.C.; Popky, G.L.

    1983-04-01

    Our experience with high-resolution computed tomography has indicated that the accepted norms for appearance and size of the pituitary gland may not be entirely valid for women of childbearing age. Fifty women with normal menstrual histories and who were not taking oral contraceptives were studied. The study consisted of overlapping 1.5-mm sections through the pituitary fossa in the coronal position only, using a bolus of contrast material followed by a continuous drip during the study. The results indicate that the top of the normal range of gland height is well over the accepted 7 mm and that focal defects within the gland are common. Other variables such as gland shape, width, and overall density were also evaluated.

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. [The evaluation of the physical characteristics of a volumetric computer tomograph].

    PubMed

    Crespi, A; Leoni, S; Montanari, G; Paruccini, N; Pedroli, G; Grimaldi, M; Salvini, E

    1996-04-01

    Spiral or volumetric computed tomography (CT) is a new scanning technique which allows the scanning of body regions with a continuously rotating system based on the slip ring technology; the patient is also moved continuously, synchronously with data acquisition. The physical characteristics of spiral CT image acquisition were compared with those of conventional CT images. The modulation transfer function (MTF) has the same values for medium-resolution filters, but lower values for spiral CT for high-resolution and frequency-enhancement filters. The slice sensitivity profile (SSP) describes the longitudinal image resolution for multiplanar reconstructions and was measured in terms of FWHM of the SSP curve. We obtained, for 10-mm slice thickness, a FWHM = 10.4 mm (conventional CT), versus 10.7 mm (Spiral CT), while, for 5-mm slice thickness, the corresponding values were 5.2 mm (conventional CT) and 5.5 mm (spiral CT). Noise was evaluated simply by measuring the standard deviation of the CT numbers, in a region of interest, of a uniform image and with the power spectrum or Wiener spectrum of the same image. To assess overall image quality and yield, the noise equivalent quanta (NEQ) value was also calculated. The values were a little lower for the spiral technique, particularly with high-resolution and enhancement or convolution filters. Dosimetric evaluation of the computed tomography dose index (CTDI) and of the multiple scan average dose (MSAD) was done using an acquisition protocol for average lung dose, in an anthropomorphic phantom and with TL dosimeters. The MSAD was 6.17 +/- 0.20 cGy for conventional CT and 5.98 +/- 0.23 cGy for Spiral CT, while lung dose was 3.25 +/- 0.12 cGy and 3.01 +/- 0.16 cGy, respectively.

  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. EEG source imaging with spatio-temporal tomographic nonnegative independent component analysis.

    PubMed

    Valdés-Sosa, Pedro A; Vega-Hernández, Mayrim; Sánchez-Bornot, José Miguel; Martínez-Montes, Eduardo; Bobes, María Antonieta

    2009-06-01

    This article describes a spatio-temporal EEG/MEG source imaging (ESI) that extracts a parsimonious set of "atoms" or components, each the outer product of both a spatial and a temporal signature. The sources estimated are localized as smooth, minimally overlapping patches of cortical activation that are obtained by constraining spatial signatures to be nonnegative (NN), orthogonal, sparse, and smooth-in effect integrating ESI with NN-ICA. This constitutes a generalization of work by this group on the use of multiple penalties for ESI. A multiplicative update algorithm is derived being stable, fast and converging within seconds near the optimal solution. This procedure, spatio-temporal tomographic NN ICA (STTONNICA), is equally able to recover superficial or deep sources without additional weighting constraints as tested with simulations. STTONNICA analysis of ERPs to familiar and unfamiliar faces yields an occipital-fusiform atom activated by all faces and a more frontal atom that only is active with familiar faces. The temporal signatures are at present unconstrained but can be required to be smooth, complex, or following a multivariate autoregressive model.

  1. Contrast Enhanced Computed Tomographic Study on the Prevalence of Duodenal Diverticulum in Indian Population

    PubMed Central

    Chandramohan, Anuradha; Chandran, B. Sudhakar; Jayaseelan, Visalakshi; Suganthy, J.

    2016-01-01

    Introduction Duodenal diverticulum (DD) is the second most common diverticulum, yet its incidence varies widely from 1–22% based on the mode of investigation. Computed Tomography (CT) of abdomen is the preferred modality to diagnose acute abdomen including those of complications of DD. Moreover, the prevalence of DD in Indian population is not yet been studied using CT. Aim The current study aim to look for the prevalence of DD in Indian population using Contrast Enhanced Computed Tomography (CECT) abdomen. Materials and Methods A retrospective study was done to assess the presence of DD using the CECT abdomen of 565 patients. The number, size, location, wall thickness and the contents of the diverticulum were noted. The data obtained was analysed using SPSS version 17.0. The mean, percentage of frequency of each variable and the association of DD with pancreatitis, cholelithiasis and colonic diverticulum were also looked for. Frequencies and percentages were calculated for all categorical variables. Spearman’s rho correlation was done for age, diameter and content of DD. Results The prevalence of DD in Indian population was 8.3% with the mean diameter of 17.13mm+7.26. The prevalence increased with age with no sex predilection. 89.3% were solitary and 10.64% were multiple. It was predominantly seen in the second part of duodenum (90.38%) and juxtapapillary type was the commonest. As the diameter of DD increased, fluid became its content. No significant association was observed between the presence of DD with pancreatitis, cholelithiasis or colonic diverticulum. A case of periampullary carcinoma arising from DD, a rare entity is being reported in this study. Conclusion The prevalence of DD in Indian population is high compared to western population. DD has been attributed to the cases of acute abdomen and fluid alone as a content of DD with an incidence of 1.92% can be mistaken for a cystic neoplasm of pancreas. Rarely, a periampullary carcinoma can also arise

  2. Hyperbaric computed tomographic measurement of lung compression in seals and dolphins.

    PubMed

    Moore, Michael John; Hammar, Terrence; Arruda, Julie; Cramer, Scott; Dennison, Sophie; Montie, Eric; Fahlman, Andreas

    2011-07-15

    Lung compression of vertebrates as they dive poses anatomical and physiological challenges. There has been little direct observation of this. A harbor and a gray seal, a common dolphin and a harbor porpoise were each imaged post mortem under pressure using a radiolucent, fiberglass, water-filled pressure vessel rated to a depth equivalent of 170 m. The vessel was scanned using computed tomography (CT), and supported by a rail and counterweighted carriage magnetically linked to the CT table movement. As pressure increased, total buoyancy of the animals decreased and lung tissue CT attenuation increased, consistent with compression of air within the lower respiratory tract. Three-dimensional reconstructions of the external surface of the porpoise chest showed a marked contraction of the chest wall. Estimation of the volumes of different body compartments in the head and chest showed static values for all compartments except the lung, which showed a pressure-related compression. The depth of estimated lung compression ranged from 58 m in the gray seal with lungs inflated to 50% total lung capacity (TLC) to 133 m in the harbor porpoise with lungs at 100% TLC. These observations provide evidence for the possible behavior of gas within the chest of a live, diving mammal. The estimated depths of full compression of the lungs exceeds previous indirect estimates of the depth at which gas exchange ceases, and concurs with pulmonary shunt measurements. If these results are representative for living animals, they might suggest a potential for decompression sickness in diving mammals.

  3. Real-time 3D computed tomographic reconstruction using commodity graphics hardware

    NASA Astrophysics Data System (ADS)

    Xu, Fang; Mueller, Klaus

    2007-07-01

    The recent emergence of various types of flat-panel x-ray detectors and C-arm gantries now enables the construction of novel imaging platforms for a wide variety of clinical applications. Many of these applications require interactive 3D image generation, which cannot be satisfied with inexpensive PC-based solutions using the CPU. We present a solution based on commodity graphics hardware (GPUs) to provide these capabilities. While GPUs have been employed for CT reconstruction before, our approach provides significant speedups by exploiting the various built-in hardwired graphics pipeline components for the most expensive CT reconstruction task, backprojection. We show that the timings so achieved are superior to those obtained when using the GPU merely as a multi-processor, without a drop in reconstruction quality. In addition, we also show how the data flow across the graphics pipeline can be optimized, by balancing the load among the pipeline components. The result is a novel streaming CT framework that conceptualizes the reconstruction process as a steady flow of data across a computing pipeline, updating the reconstruction result immediately after the projections have been acquired. Using a single PC equipped with a single high-end commodity graphics board (the Nvidia 8800 GTX), our system is able to process clinically-sized projection data at speeds meeting and exceeding the typical flat-panel detector data production rates, enabling throughput rates of 40-50 projections s-1 for the reconstruction of 5123 volumes.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. 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

  9. Spiral Computed Tomographic Angiography of the Renal Arteries: A Prospective Comparison with Intravenous and Intraarterial Digital Subtraction Angiography

    SciTech Connect

    Farres, Maria Teresa; Lammer, Johannes; Schima, Wolfgang; Wagner, Brunhilde; Wildling, Reinhard; Winkelbauer, Friedrich; Thurnher, Siegfried

    1996-03-15

    Purpose: To assess the accuracy of computed tomographic angiography (CTA) in the evaluation of the renal arteries in comparison with intravenous (IVDSA) and intraarterial digital subtraction angiography (IADSA). Methods: In 18 patients, 35 CTAs and DSAs (27 IADSA, 8 IVDSA) of the renal arteries were performed. CTA was done with 2-3 mm collimation, 2-4 mm/sec table speed, after intravenous injection of 80 ml of contrast medium at 4 ml/sec with a scanning delay time of 14-21 sec. No previous circulation time curve was performed. CTA data were reconstructed with maximum intensity projection (MIP) and shaded surface display (SSD). The presence of stenosis was assessed on a three-point rating scale (grade 1-3). The quality of the examinations; visualization of the ostium, the main artery, and its branches; vessel sharpness, linearity, and intraluminal contrast filling were evaluated. We compared CTA with DSA. Results: CTA had 96% sensitivity, 77% specificity, and 89% accuracy in the detection of stenoses > 50%. Due to technical errors two stenoses were erroneously diagnosed as positive but there were no false negative diagnoses. The quality of CTA was good in 56% and moderate in 34% of cases. Visualization of the ostium and main artery was graded as 1.74 (out of 2) points and of the renal branches as 1.02 (out of 2) points. The quality of CTA images was worse than that of IADSA in 52%, equal in 41%, and better in 7% of cases. CTA was equal to IVDSA in 25% and better in 75% of the cases. Conclusion: CTA is an accurate noninvasive method for the evaluation of renal arteries. Examination quality is essential for the diagnosis. CTA is limited in its ability to visualize the branches of the renal artery and accessory arteries. CTA seems to be superior to IVDSA.

  10. An interactive 3D visualization and manipulation tool for effective assessment of angiogenesis and arteriogenesis using computed tomographic angiography

    NASA Astrophysics Data System (ADS)

    Shen, Li; Gao, Ling; Zhuang, Zhenwu; DeMuinck, Ebo; Huang, Heng; Makedon, Fillia; Pearlman, Justin

    2005-04-01

    This paper presents IVM, an Interactive Vessel Manipulation tool that can help make effective and efficient assessment of angiogenesis and arteriogenesis in computed tomographic angiography (CTA) studies. IVM consists of three fundamental components: (1) a visualization component, (2) a tracing component, and (3) a measurement component. Given a user-specified threshold, IVM can create a 3D surface visualization based on it. Since vessels are thin and tubular structures, using standard isosurface extraction techniques usually cannot yield satisfactory reconstructions. Instead, IVM directly renders the surface of a derived binary 3D image. The image volumes collected in CTA studies often have a relatively high resolution. Thus, compared with more complicated vessel extraction and visualization techniques, rendering the binary image surface has the advantages of being effective, simple and fast. IVM employs a semi-automatic approach to determine the threshold: a user can adjust the threshold by checking the corresponding 3D surface reconstruction and make the choice. Typical tracing software often defines ROIs on 3D image volumes using three orthogonal views. The tracing component in IVM takes one step further: it can perform tracing not only on image slices but also in a 3D view. We observe that directly operating on a 3D view can help a tracer identify ROIs more easily. After setting a threshold and tracing an ROI, a user can use IVM's measurement component to estimate the volume and other parameters of vessels in the ROI. The effectiveness of the IVM tool is demonstrated on rat vessel/bone images collected in a previous CTA study.

  11. [The computed tomographic semiotics of inflammatory diseases of the adnexa uteri].

    PubMed

    Todua, F I; Karmazanovskiĭ, G G; Podzolkova, N M

    1990-01-01

    The authors sum up the results of CT and clinical investigation of 46 women with inflammatory diseases of the uterine appendages: salpingo-oophoritis, pyosalpinx, pyoovarium, and 2 types of tuboovarian abscesses. They have shown CT potentialities in differential diagnosis of inflammations of the uterine appendages with cysts and true ovarian tumors on the basis of routine investigation and an iv contrast study of intensified images. Retrospective analysis of the most typical diagnostic errors is given.

  12. 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.

  13. A computed tomographic scan assessment of endotracheal suctioning-induced bronchoconstriction in ventilated sheep.

    PubMed

    Lu, Q; Capderou, A; Cluzel, P; Mourgeon, E; Abdennour, L; Law-Koune, J D; Straus, C; Grenier, P; Zelter, M; Rouby, J J

    2000-11-01

    This study was directed at assessing changes in bronchial cross-sectional surface areas (BCSA) and in respiratory resistance induced by endotracheal suctioning in nine anesthetized sheep. Cardiorespiratory parameters (Swan-Ganz catheter), respiratory resistance (inspiratory occlusion technique), BCSA, and lung aeration (computed tomography) were studied at baseline, during endotracheal suctioning, and after 20 consecutive hyperinflations. Measurements performed initially at an inspired oxygen fraction (FI(O(2))) of 0.3 were repeated at an FI(O(2)) of 1.0. At an FI(O(2)) of 0.3, endotracheal suctioning resulted in atelectasis, a reduction in BCSA of 29 +/- 23% (mean +/- SD), a decrease in arterial oxygen saturation from 95 +/- 3% to 87 +/- 12% (p = 0.02), an increase in venous admixture from 19 +/- 10% to 31 +/- 19% (p = 0. 006), and an increase in lung tissue resistance (DR(rs)) (p = 0. 0003). At an FI(O(2)) of 1.0, despite an extension of atelectasis and an increase in pulmonary shunt from 19 +/- 5% to 36 +/- 2% (p < 0.0001), arterial O(2) desaturation was prevented and BCSA decreased by only 7 +/- 32%. A recruitment maneuver after endotracheal suctioning entirely reversed the suctioning-induced increase in DR(rs) and atelectasis. In three lidocaine-pretreated sheep, the endotracheal suctioning-induced reduction of BCSA was entirely prevented. These data suggest that the endotracheal suctioning-induced decrease in BCSA is related to atelectasis and bronchoconstriction. Both effects can be reversed by hyperoxygenation maneuver before suctioning in combination with recruitment maneuver after suctioning.

  14. 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.

  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 Measures of Pulmonary Vascular Morphology in Smokers and Their Clinical Implications

    PubMed Central

    Estépar, Raúl San José; Kinney, Gregory L.; Black-Shinn, Jennifer L.; Bowler, Russell P.; Kindlmann, Gordon L.; Ross, James C.; Kikinis, Ron; Han, MeiLan K.; Come, Carolyn E.; Diaz, Alejandro A.; Cho, Michael H.; Hersh, Craig P.; Schroeder, Joyce D.; Reilly, John J.; Lynch, David A.; Crapo, James D.; Wells, J. Michael; Dransfield, Mark T.; Hokanson, John E.

    2013-01-01

    Rationale: Angiographic investigation suggests that pulmonary vascular remodeling in smokers is characterized by distal pruning of the blood vessels. Objectives: Using volumetric computed tomography scans of the chest we sought to quantitatively evaluate this process and assess its clinical associations. Methods: Pulmonary vessels were automatically identified, segmented, and measured. Total blood vessel volume (TBV) and the aggregate vessel volume for vessels less than 5 mm2 (BV5) were calculated for all lobes. The lobe-specific BV5 measures were normalized to the TBV of that lobe and the nonvascular tissue volume (BV5/TissueV) to calculate lobe-specific BV5/TBV and BV5/TissueV ratios. Densitometric measures of emphysema were obtained using a Hounsfield unit threshold of −950 (%LAA-950). Measures of chronic obstructive pulmonary disease severity included single breath measures of diffusing capacity of carbon monoxide, oxygen saturation, the 6-minute-walk distance, St George’s Respiratory Questionnaire total score (SGRQ), and the body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index. Measurements and Main Results: The %LAA-950 was inversely related to all calculated vascular ratios. In multivariate models including age, sex, and %LAA-950, lobe-specific measurements of BV5/TBV were directly related to resting oxygen saturation and inversely associated with both the SGRQ and BODE scores. In similar multivariate adjustment lobe-specific BV5/TissueV ratios were inversely related to resting oxygen saturation, diffusing capacity of carbon monoxide, 6-minute-walk distance, and directly related to the SGRQ and BODE. Conclusions: Smoking-related chronic obstructive pulmonary disease is characterized by distal pruning of the small blood vessels (<5 mm2) and loss of tissue in excess of the vasculature. The magnitude of these changes predicts the clinical severity of disease. PMID:23656466

  17. 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

  18. 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

    2013-03-22

    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.

  19. Early postmortem volume reduction of adrenal gland: initial longitudinal computed tomographic study.

    PubMed

    Ishida, Masanori; Gonoi, Wataru; Hagiwara, Kazuchika; Okuma, Hidemi; Shirota, Go; Shintani, Yukako; Abe, Hiroyuki; Takazawa, Yutaka; Fukayama, Masashi; Ohtomo, Kuni

    2015-07-01

    We aimed to confirm whether postmortem adrenal volumetric changes occur by measuring adrenal volumes on computed tomography (CT). Fifty-five adrenal glands from 28 subjects who died were included. All subjects underwent antemortem CT (AMCT) and postmortem CT (PMCT) within 94-1,191 min after death, followed by conventional autopsy. CT volumetry was performed using freely-available software. Differences between AMCT and PMCT adrenal volumes were evaluated statistically along with differences in the degree of volume change, elapsed time to PMCT, and presence of underlying malignant disease. The mean volume of the right adrenal gland decreased from 3.8 cm(3) on AMCT to 2.6 cm(3) on PMCT (P < 0.001); the left adrenal gland decreased from 4.2 cm(3) on AMCT to 3.1 cm(3) on PMCT (P < 0.001). Conventional autopsy revealed decreased intracellular lipid components in portions of the adrenal glands. No correlation between the adrenal gland reduction rate and the elapsed time from AMCT to death or from death to PMCT was observed (P = 0.99 and 0.79; P = 0.28 and 0.59 for the right and left adrenal glands, respectively). Significant differences in both the bilateral adrenal gland reduction rates and underlying malignant disease were found for the left adrenal gland (P = 0.015), but not for the right (P = 0.74). Adrenal volume reduction was observed on PMCT compared to AMCT. This highlights the need to further elucidate the mechanism of adrenal shrinkage during the agonal stage and after death. This may be explained by pathological findings of intracellular lipid depletion.

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

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

    PubMed

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

    2016-04-01

    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 results

  6. Multi-Rate Mass Transfer : Computing the Memory Function Using Micro-Tomographic Images

    NASA Astrophysics Data System (ADS)

    Gouze, P.; Melean, Y.; Leborgne, T.; Carrera, J.

    2006-12-01

    Several in situ and laboratory experiments display strongly dissymmetrical breakthrough curves (BTC), ending up with a concentration decrease with time close to C(t) ~ t ^{-γ}. Matrix diffusion is a widely recognized process producing this class of non-Fickean transport behavior characterized by an apparently infinite variance of the temporal distribution. The matrix diffusion sink/source term in the macroscopic advection dispersion transport equation can be expressed by the convolution product of a memory function G(t) times the concentration measured in the mobile (advective) part of the aquifer. Memory function, displaying power law decrease C(t) ~ t ^{1-γ} at early time, can be obtained by assuming an immobile domain made of single diffusion length structures, such as spheres or slabs. Indeed, diffusion in a distribution of spheres of different size may produce a large spectrum of power law memory function. However, the structure of the immobile domain of real rocks is generally completely different from spheres-made rocks. Here, we present a method for calculating the true memory function of heterogeneous structures (reef calcareous rocks) using 3D X-Ray micro-tomography images of rock samples. Several steps of data processing are required to quantify precisely the structure, the porosity distribution and the properties of the mobile/immobile interface, before solving the diffusion problem (here using random walk approach). Conversely, tracer experiments (at meter scale) are performed in the same medium. The obtained BTCs display long tailing decrease over several orders of magnitude. Using very few assumptions, one compute memory functions (measured on centimeter scale samples) similar to those expected to control the BTCs at meter scale. Results show that the memory function is strongly controlled by the diffusivity distribution in the matrix and, to a lesser extent, by the mobile-immobile interface geometry; so that power law exponents of the BTCs tail

  7. Decreased Diagnostic Accuracy of Multislice Coronary Computed Tomographic Angiography in Women with Atypical Angina Symptoms

    PubMed Central

    Jin, Wen-Ying; Zhao, Xiu-Juan; Chen, Hong

    2016-01-01

    Background: Multislice computed tomography (MSCT) coronary angiography (CAG) is a noninvasive technique with a reported high diagnostic accuracy for coronary artery disease (CAD). Women, more frequently than men, are known to develop atypical angina symptoms. The purpose of this study was to investigate whether the diagnostic accuracy of MSCT in women with atypical presentation differs from that in men. Methods: We enrolled 396 in-hospital patients (141 women and 255 men) with suspected or proven CAD who successively underwent both MSCT and invasive CAG. CAD was defined as any coronary stenosis of ≥50% on conventional invasive CAG, which was used as the reference standard. The patients were divided into typical and atypical groups based on their symptoms of angina pectoris. The diagnostic accuracy of MSCT, including its sensitivity, specificity, negative predictive value, and positive predictive value (PPV), was calculated to determine the usefulness of MSCT in assessing stenoses. The diagnostic performance of MSCT was also assessed by constructing receiver operating characteristic (ROC) curves. Results: The PPV (91% vs. 97%, χ2 = 5.705, P < 0.05) and diagnostic accuracy (87% vs. 93%, χ2 = 5.093, P < 0.05) of MSCT in detecting CAD were lower in women than in men. Atypical presentation was an independent influencing factor on the diagnostic accuracy of MSCT in women (odds ratio = 4.94, 95% confidence intervals: 1.16–20.92, Walds = 4.69, P < 0.05). Compared with those in the atypical group, women with typical angina pectoris had higher PPV (98% vs. 74%, χ2 = 17.283. P < 0.001), diagnostic accuracy (93% vs. 72%, χ2 = 9.571, P < 0.001), and area under the ROC curve (0.91 vs. 0.64, Z = 2.690, P < 0.01) in MSCT diagnosis. Conclusions: Although MSCT is a reliable diagnostic modality for the exclusion of significant coronary artery stenoses in all patients, gender and atypical symptoms might have some influence on its diagnostic accuracy. PMID:27625091

  8. Low-density lipoprotein and noncalcified coronary plaque composition in patients with newly diagnosed coronary artery disease on computed tomographic angiography.

    PubMed

    Cheng, Victor Y; Wolak, Arik; Gutstein, Ariel; Gransar, Heidi; Wong, Nathan D; Dey, Damini; Thomson, Louise E J; Hayes, Sean W; Friedman, John D; Slomka, Piotr J; Berman, Daniel S

    2010-03-15

    We sought to determine significant relations between atherogenic lipoproteins and the contribution of calcified plaque (CP), mixed plaque (MP), and noncalcified plaque (NCP) to the total plaque (TP) burden in patients without previous coronary artery disease. From 823 adult patients without previously established coronary artery disease (52% receiving statin therapy, 34% asymptomatic) but with visible coronary plaque on coronary computed tomographic angiography, we obtained segmental CP, MP, NCP, and TP counts from contrast-enhanced, electrocardiographic-gated computed tomography. Multivariate linear regression analysis was used to determine the associations of clinical factors and lipoprotein levels to CP, MP, and NCP counts and CP/TP, MP/TP, and NCP/TP count ratios. Age, male gender, diabetes, smoking, and statin therapy were significantly associated with the CP count (p <0.001, p <0.001, p = 0.049, p = 0.016, and p = 0.003, respectively). Low-density lipoprotein (LDL) cholesterol was significantly associated with MP and NCP counts (all p values

  9. Tomographic PIV: principles and practice

    NASA Astrophysics Data System (ADS)

    Scarano, F.

    2013-01-01

    A survey is given of the major developments in three-dimensional velocity field measurements using the tomographic particle image velocimetry (PIV) technique. The appearance of tomo-PIV dates back seven years from the present review (Elsinga et al 2005a 6th Int. Symp. PIV (Pasadena, CA)) and this approach has rapidly spread as a versatile, robust and accurate technique to investigate three-dimensional flows (Arroyo and Hinsch 2008 Topics in Applied Physics vol 112 ed A Schröder and C E Willert (Berlin: Springer) pp 127-54) and turbulence physics in particular. A considerable number of applications have been achieved over a wide range of flow problems, which requires the current status and capabilities of tomographic PIV to be reviewed. The fundamental aspects of the technique are discussed beginning from hardware considerations for volume illumination, imaging systems, their configurations and system calibration. The data processing aspects are of uppermost importance: image pre-processing, 3D object reconstruction and particle motion analysis are presented with their fundamental aspects along with the most advanced approaches. Reconstruction and cross-correlation algorithms, attaining higher measurement precision, spatial resolution or higher computational efficiency, are also discussed. The exploitation of 3D and time-resolved (4D) tomographic PIV data includes the evaluation of flow field pressure on the basis of the flow governing equation. The discussion also covers a-posteriori error analysis techniques. The most relevant applications of tomo-PIV in fluid mechanics are surveyed, covering experiments in air and water flows. In measurements in flow regimes from low-speed to supersonic, most emphasis is given to the complex 3D organization of turbulent coherent structures.

  10. 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.

  11. Point-based superimposition of a digital dental model on to a three-dimensional computed tomographic skull: an accuracy study in vitro.

    PubMed

    Lin, X; Chen, T; Liu, J; Jiang, T; Yu, D; Shen, S G F

    2015-01-01

    We investigated the accuracy of point-based superimposition of a digital dental model on to a 3-dimensional computed tomographic (CT) skull with intact dentition. The physical model was scanned by CT to give a virtual skull model, and a plaster dental model was taken and laser-scanned to give a digital dental model. Three different background investigators were recruited and calibrated to make the point-based superimposition, and afterwards were asked to repeat 5 superimpositions each. Five bone-to-tooth measurements for the maxilla and 6 for the mandible were selected to indicate the relation of teeth to skull. Repeated measures were made on the physical model to act as a control group, and on the virtual model to act as the test group. The absolute agreement intra-class correlation coefficient (ICC) was used to assess the intra/inter-investigator reliability; Bland-Altman analysis was used to calculate the general differences, limits of agreement, and precision ranges of the estimated limits. Inter/intra-investigator reliability was excellent with ICC varying from 0.986 to 1; Bland-Altman analysis indicated that general difference was 0.01 (0.25)mm, the upper limit of agreement was 0.50mm and the lower limit -0.47 mm, and the precision range for the upper limit was 0.43 mm to 0.57 mm and for the lower limit -0.54 mm to -0.40 mm. Clinically acceptable accuracy can be achieved using a direct point-based method to superimpose a digital dental model on to a 3-dimensional CT skull.

  12. 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

  13. Organ dose measurements from multiple-detector computed tomography using a commercial dosimetry system and tomographic, physical phantoms

    NASA Astrophysics Data System (ADS)

    Lavoie, Lindsey K.

    The technology of computed tomography (CT) imaging has soared over the last decade with the use of multi-detector CT (MDCT) scanners that are capable of performing studies in a matter of seconds. While the diagnostic information obtained from MDCT imaging is extremely valuable, it is important to ensure that the radiation doses resulting from these studies are at acceptably safe levels. This research project focused on the measurement of organ doses resulting from modern MDCT scanners. A commercially-available dosimetry system was used to measure organ doses. Small dosimeters made of optically-stimulated luminescent (OSL) material were analyzed with a portable OSL reader. Detailed verification of this system was performed. Characteristics studied include energy, scatter, and angular responses; dose linearity, ability to erase the exposed dose and ability to reuse dosimeters multiple times. The results of this verification process were positive. While small correction factors needed to be applied to the dose reported by the OSL reader, these factors were small and expected. Physical, tomographic pediatric and adult phantoms were used to measure organ doses. These phantoms were developed from CT images and are composed of tissue-equivalent materials. Because the adult phantom is comprised of numerous segments, dosimeters were placed in the phantom at several organ locations, and doses to select organs were measured using three clinical protocols: pediatric craniosynostosis, adult brain perfusion and adult cardiac CT angiography (CTA). A wide-beam, 320-slice, volumetric CT scanner and a 64-slice, MDCT scanner were used for organ dose measurements. Doses ranged from 1 to 26 mGy for the pediatric protocol, 1 to 1241 mGy for the brain perfusion protocol, and 2-100 mGy for the cardiac protocol. In most cases, the doses measured on the 64-slice scanner were higher than those on the 320-slice scanner. A methodology to measure organ doses with OSL dosimeters received from CT

  14. Field evaporation behaviour in the gamma phase in Ti-Al during analysis in the tomographic atom probe.

    PubMed

    Lefebvre, W; Loiseau, A; Menand, A

    2002-07-01

    A Ti-48 at% Al alloy has been successfully investigated, using atom probe field ion microscopy and transmission electron microscopy. After a specific heat treatment, this alloy has a (alpha2 + gamma) lamellar microstructure. Using the tomographic atom probe (TAP), it has been possible to image the stacking of superlattice planes of gamma and to identify titanium as the highest evaporation field element. In addition, the influence of analysis site on atom probe measurements has been estimated for this phase. A TAP analysis has also made it possible to observe an extremely thin step along a gamma/gamma interface at a near atomic scale.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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

    2016-07-22

    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.

  4. 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

  5. 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

  6. 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.

  7. 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

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. Development of a 30-week-pregnant female tomographic model from computed tomography (CT) images for Monte Carlo organ dose calculations.

    PubMed

    Shi, Chengyu; Xu, X George

    2004-09-01

    Assessment of radiation dose and risk to a pregnant woman and her fetus is an important task in radiation protection. Although tomographic models for male and female patients of different ages have been developed using medical images, such models for pregnant women had not been developed to date. This paper reports the construction of a partial-body model of a pregnant woman from a set of computed tomography (CT) images. The patient was 30 weeks into pregnancy, and the CT scan covered the portion of the body from above liver to below pubic symphysis in 70 slices. The thickness for each slice is 7 mm, and the image resolution is 512x512 pixels in a 48 cm x 48 cm field; thus, the voxel size is 6.15 mm3. The images were segmented to identify 34 major internal organs and tissues considered sensitive to radiation. Even though the masses are noticeably different from other models, the three-dimensional visualization verified the segmentation and its suitability for Monte Carlo calculations. The model has been implemented into a Monte Carlo code, EGS4-VLSI (very large segmented images), for the calculations of radiation dose to a pregnant woman. The specific absorbed fraction (SAF) results for internal photons were compared with those from a stylized model. Small and large differences were found, and the differences can be explained by mass differences and by the relative geometry differences between the source and the target organs. The research provides the radiation dosimetry community with the first voxelized tomographic model of a pregnant woman, opening the door to future dosimetry studies. PMID:15487729

  18. Superimposition-based personal identification using skull computed tomographic images: application to skull with mouth fixed open by residual soft tissue.

    PubMed

    Ishii, Masuko; Saitoh, Hisako; Yasjima, Daisuke; Yohsuk, Makino; Sakuma, Ayaka; Yayama, Kazuhiro; Iwase, Hirotaro

    2013-09-01

    We previously reported that superimposition of 3-dimensional (3D) images reconstructed from computed tomographic images of skeletonized skulls on photographs of the actual skulls afforded a match of skull contours, thereby demonstrating that superimposition of 3D-reconstructed images provides results identical to those obtained with actual skulls. The current superimposition procedure requires a skeletonized skull with mouth closed and thus is not applicable to personal identification using a skull with residual soft tissue or the mouth fixed open, such as those found in mummified or burned bodies. In this study, we scanned using computed tomography the skulls of mummified and immersed body with mandibles fixed open by residual soft tissue, created 3D-reconstructed skull images, which were digitally processed by computer software to close the mandible, and superimposed the images on antemortem facial photographs. The results demonstrated morphological consistency between the 3D-reconstructed skull images and facial photographs, indicating the applicability of the method to personal identification.

  19. 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.

  20. Accuracy and reliability of linear measurements using 3-dimensional computed tomographic imaging software for Le Fort I Osteotomy.

    PubMed

    Gaia, Bruno Felipe; Pinheiro, Lucas Rodrigues; Umetsubo, Otávio Shoite; Santos, Oseas; Costa, Felipe Ferreira; Cavalcanti, Marcelo Gusmão Paraíso

    2014-03-01

    Our purpose was to compare the accuracy and reliability of linear measurements for Le Fort I osteotomy using volume rendering software. We studied 11 dried skulls and used cone-beam computed tomography (CT) to generate 3-dimensional images. Linear measurements were based on craniometric anatomical landmarks that were predefined as specifically used for Le Fort I osteotomy, and identified twice each by 2 radiologists, independently, using Dolphin imaging version 11.5.04.35. A third examiner then made physical measurements using digital calipers. There was a significant difference between Dolphin imaging and the gold standard, particularly in the pterygoid process. The largest difference was 1.85mm (LLpPtg L). The mean differences between the physical and the 3-dimensional linear measurements ranged from -0.01 to 1.12mm for examiner 1, and 0 to 1.85mm for examiner 2. Interexaminer analysis ranged from 0.51 to 0.93. Intraexaminer correlation coefficients ranged from 0.81 to 0.96 and 0.57 to 0.92, for examiners 1 and 2, respectively. We conclude that the Dolphin imaging should be used sparingly during Le Fort I osteotomy.

  1. Stature estimation in Japanese cadavers based on pelvic measurements in three-dimensional multidetector computed tomographic images.

    PubMed

    Torimitsu, Suguru; Makino, Yohsuke; Saitoh, Hisako; Sakuma, Ayaka; Ishii, Namiko; Hayakawa, Mutsumi; Yajima, Daisuke; Inokuchi, Go; Motomura, Ayumi; Chiba, Fumiko; Iwase, Hirotaro

    2015-05-01

    The aim of this study was to examine the feasibility of stature estimation by measuring the pelvic bones of Japanese cadavers using three-dimensional (3D) computed tomography (CT). We assessed 3D reconstructed images of 210 Japanese subjects (108 males, 102 females) who had undergone postmortem CT between May 2011 and November 2013. We defined the linear distance from the anterosuperior margin of the left and right anterior superior iliac spines (ASIS) to the posterior margin of the left and right ischial spines as the LSS and RSS, respectively. We also defined the linear distance from the anterosuperior margin of the left and right ASIS to the anteroinferior margin of the left and right ischial tuberosities as the LST and RST, respectively. The correlation between the cadaver stature (CS) and each parameter (LSS, LST, RSS, and RST) was evaluated using Pearson product-moment correlation coefficients and regression analysis was performed for stature estimation. All four parameters correlated significantly with stature independent of sex, suggesting that they can be used as a tool for stature estimation. The LST had the closest correlation with stature in both sexes.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. Robust mean traveltime curves: a powerful tool for analysis in 2D transmission tomographic surveys

    NASA Astrophysics Data System (ADS)

    Fernandez Martinez, J.; Pedruelo Gonzalez, L.; Rector, J.

    2008-12-01

    Acoustic tomography methods belong to the class of non destructive inspection techniques and are widely used in engineering applications. One of the main issues for these methods is the direct arrivals, which can be noisy or affected by scattering or other propagation effects. Mean traveltime curves (mean and standard deviation) have been introduced by Fernández Martínez et al (2006), and describe the variation of the main statistical parameters of the traveltime distribution for the different gathering subsets as a function of the gather index. These curves constitute a simple methodology (Fernández Martínez et al., 2008) to analyze before inversion the traveltime quality in 2D acoustic transmission tomography experiments conducted in relatively homogeneous blocks. This analysis can help to discriminate the contribution of picking errors from that of geological heterogeneities. In this contribution we present the so-called robust mean traveltime curves, which refer to the variation of the different p-percentiles and related measures of dispersion (inter-quartile range and minimum absolute deviation) for the above mentioned gathering subsets. Together with the mean curve, the median and upper-quartile traveltime curves are very resistant to the presence of outliers, and thus, are preferred to infer a background velocity model, which is valid at experiment scale and honors the experimental traveltime distribution. This methodology is valid for 2D zonal isotropic or elliptical anisotropic media, explored via any arbitrary acquisition geometry. We show the application to a well-known granitic medium (Febex Project, Nagra, Switzerland). Fernández Martínez et al. 2006. Mathematical Geology:38-3.343-374 Fernández Martínez et al.2008. Computer and Geosciences:34-3,213-225, 2008.

  8. 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.

  9. 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.

  10. Structural analysis of the human tibia by tomographic (pQCT) serial scans.

    PubMed

    Capozza, Ricardo Francisco; Feldman, Sara; Mortarino, Pablo; Reina, Paola Soledad; Schiessl, Hans; Rittweger, Jörn; Ferretti, José Luis; Cointry, Gustavo Roberto

    2010-04-01

    This study analyses the evaluation of tomographic indicators of tibia structure, assuming that the usual loading pattern shifts from uniaxial compression close to the heel to a combined compression, torsion and bending scheme towards the knee. To this end, pQCT scans were obtained at 5% intervals of the tibia length (S5-S95 sites from heel to knee) in healthy men and women (10/10) aged 20-40 years. Indicators of bone mass [cortical area, cortical/total bone mineral content (BMC)], diaphyseal design (peri/endosteal perimeters, cortical thickness, circularity, bending/torsion moments of inertia - CSMIs), and material quality [(cortical vBMD (bone mineral density)] were determined. The longitudinal patterns of variation of these measures were similar between genders, but male values were always higher except for cortical vBMD. Expression of BMC data as percentages of the minimal values obtained along the bone eliminated those differences. The correlative variations in cortical area, BMC and thickness, periosteal perimeter and CSMIs along the bone showed that cortical bone mass was predominantly associated with cortical thickness toward the mid-diaphysis, and with bone diameter and CSMIs moving more proximally. Positive relationships between CSMIs (y) and total BMC (x) showed men's values shifting to the upper-right region of the graph and women's values shifting to the lower-left region. Total BMC decayed about 33% from S5 to S15 (where minimum total BMC and CSMI values and variances and maximum circularity were observed) and increased until S45, reaching the original S5 value at S40. The observed gender-related differences reflected the natural allometric relationships. However, the data also suggested that men distribute their available cortical mass more efficiently than women. The minimum amount and variance of mass indicators and CSMIs, and the largest circularity observed at S15 reflected the assumed adaptation to compression pattern at that level. The increase

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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

  17. C-arm Cone Beam Computed Tomographic Needle Path Overlay for Fluoroscopic-Guided Placement of Translumbar Central Venous Catheters

    SciTech Connect

    Tam, Alda; Mohamed, Ashraf; Pfister, Marcus; Rohm, Esther; Wallace, Michael J.

    2009-07-15

    C-arm cone beam computed tomography is an advanced 3D imaging technology that is currently available on state-of-the-art flat-panel-based angiography systems. The overlay of cross-sectional imaging information can now be integrated with real-time fluoroscopy. This overlay technology was used to guide the placement of three percutaneous translumbar inferior vena cava catheters.

  18. 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

  19. 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.

  20. Computed tomographic characteristics of multilobular tumor of bone involving the cranium in 7 dogs and zygomatic arch in 2 dogs.

    PubMed

    Hathcock, J T; Newton, J C

    2000-01-01

    Computed tomography (CT) images of nine dogs with a multilobular tumor of bone of the head were reviewed. The CT characteristics of the neoplasms involving the calvarium (n = 7) were rounded, well defined with a fine granular, nonhomogeneous bone opacity usually in the occipital region. Cranial vault invasion (5 of 7) was commonly found with a significant portion of the mass within the vault. The neoplasms involving the zygomatic arch (n = 2) were also generally rounded and well defined but with a more coarse granular appearance. The common CT findings were best seen when the images were viewed in a bone window.

  1. 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.

  2. Shaping Ability of the Fifth Generation Ni-Ti Rotary Systems for Root Canal Preparation in Curved Root Canals using Cone-Beam Computed Tomographic: An In Vitro Study

    PubMed Central

    Jain, Deepak; Medha, Ashish; Patil, Neelam; Kadam, Nilam; Yadav, Vandana; Jagadale, Harshal

    2015-01-01

    Background: Various root canal systems are available commercially with each manufacturer stating superior characteristics of their respective systems. The fifth generation root canal systems claim to have better flexibility and superior debris elimination due to their offset design. This study aims to compare the effects of fifth generation rotary systems on canal curvature, transportation and centering ratio of curved mesial root canals of mandibular molar via cone-beam computed tomographic (CBCT) imaging. Materials and Methods: With curvature ranging from 20° to 40°, 60 mandibular first molars with mesiobuccal root angle were divided into three groups with 20 canals each. Before instrumentation, the groups were balanced with respect to the angle of canal curvature based on CBCT images taken. All root canals were shaped to an apical size of 25: OneShape (OS) (Micro Mega, Besancon, France), ProTaper Next (PTN) (Dentsply Maillefer), Revo S (RS) (Micro Mega, Besancon, France). CBCT assessment was done post instrumentation. SPSS version 16 software was used for statistical analysis. The significance level was set at P = 0.05. Results: The RS system maintained better canal centricity and less transportation as compared to PTN and OS. There was no significant difference among the three groups in canal curvature after instrumentation. Conclusions: All file systems used straightened the root canal curvature similarly. RS instrumentation exhibited superior performance compared with the OS and PTN systems with respect to transportation and centering ratio. PMID:26225107

  3. 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

  4. 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.

  5. 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

  6. Cone-beam computed tomographic evaluation of styloid process: a retrospective study of 208 patients with orofacial pain

    PubMed Central

    2014-01-01

    Introduction The purpose of this study was to assess the structural characteristics of styloid process (SP) by cone-beam computed tomography (CBCT) examination in a patient population suffering from orofacial pain. The second aim was to assess the prevalence of elongated SP and its relation to gender, site and subjective symptoms in the study population. Methods Clinical and radiographic records of 208 patients were evaluated retrospectively. Radiological examinations including measurements of the structure, length, and medial angulations of SP were performed on CBCT images. Results Out of 208 patients, 96 (46%) had not-elongated SP, 28 (13%) had left side, 16 (8%) had right side, and 68 (33%) had bilateral elongation of SP. The patients with elongated SP had significantly decreased angle values. There were no statistically significant differences in length values of SP between males and females in both groups. Significantly increased prevalence of symptoms except headache was observed in patients with elongated SP. Conclusions This study presents the CBCT as an alternative method to CT or panoramic radiographs for the measurement and the assessment of the styloid process. Patients suffering from orofacial pain, who also had elongated SP, had increased rate of corresponding neurological complaints compared with non-elongated ones. PMID:24528515

  7. Bone thickness of the infrazygomatic crest area in skeletal Class III growing patients: A computed tomographic study

    PubMed Central

    Lee, Hyub-Soo; Choi, Hang-Moon; Choi, Dong-Soon; Jang, Insan

    2013-01-01

    Purpose This study was performed to investigate the bone thickness of the infrazygomatic crest area by computed tomography (CT) for placement of a miniplate as skeletal anchorage for maxillary protraction in skeletal Class III children. Materials and Methods CT images of skeletal Class III children (7 boys, 9 girls, mean age: 11.4 years) were taken parallel to the Frankfurt horizontal plane. The bone thickness of the infrazygomatic crest area was measured at 35 locations on the right and left sides, perpendicular to the bone surface. Results The bone was thickest (5.0 mm) in the upper zygomatic bone and thinnest (1.1 mm) in the anterior wall of the maxillary sinus. Generally, there was a tendency for the bone to be thicker at the superior and lateral area of the zygomatic process of the maxilla. There was no clinically significant difference in bone thickness between the right and left sides; however, it was thicker in male than in female subjects. Conclusion In the infrazygomatic crest area, the superior and lateral area of the zygomatic process of the maxilla had the most appropriate thickness for placement of a miniplate in growing skeletal Class III children with a retruded maxilla. PMID:24380065

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Cephalic vascular anatomy in flamingos (Phoenicopterus ruber) based on novel vascular injection and computed tomographic imaging analyses.

    PubMed

    Holliday, Casey M; Ridgely, Ryan C; Balanoff, Amy M; Witmer, Lawrence M

    2006-10-01

    Head vascular anatomy of the greater (or Caribbean) flamingo (Phoenicopterus ruber) is investigated and illustrated through the use of a differential contrast, dual vascular injection technique, and high-resolution X-ray computed tomography (CT), allowing arteries and veins to be differentiated radiographically. Vessels were digitally isolated with segmentation tools and reconstructed in 3D to facilitate topographical visualization of the cephalic vascular tree. Major vessels of the temporal, orbital, pharyngeal, and encephalic regions are described and illustrated, which confirm that the general pattern of avian cephalic vasculature is evolutionarily conservative. In addition to numerous arteriovenous vascular devices, a previously undescribed, large, bilateral, paralingual cavernous sinus that excavates a large bony fossa on the medial surface of the mandible was identified. Despite the otherwise conservative vascular pattern, this paralingual sinus was found only in species of flamingo and is not known otherwise in birds. The paralingual sinus remains functionally enigmatic, but a mechanical role in association with the peculiar lingual-pumping mode of feeding in flamingos is perhaps the most likely hypothesis.

  13. Cone-Beam Computed Tomographic Assessment of Mandibular Condylar Position in Patients with Temporomandibular Joint Dysfunction and in Healthy Subjects

    PubMed Central

    Paknahad, Maryam; Shahidi, Shoaleh; Iranpour, Shiva; Mirhadi, Sabah; Paknahad, Majid

    2015-01-01

    Statement of the Problem. The clinical significance of condyle-fossa relationships in the temporomandibular joint is a matter of controversy. Different studies have evaluated whether the position of the condyle is a predictor of the presence of temporomandibular disorder. Purpose. The purpose of the present study was to investigate the condylar position according to gender in patients with temporomandibular disorder (TMD) and healthy controls using cone-beam computed tomography. Materials and Methods. CBCT of sixty temporomandibular joints in thirty patients with TMD and sixty joints of thirty subjects without TMJ disorder was evaluated in this study. The condylar position was assessed on the CBCT images. The data were analyzed using Pearson chi-square test. Results. No statistically significant differences were found regarding the condylar position between symptomatic and asymptomatic groups. Posterior condylar position was more frequently observed in women and anterior condylar position was more prevalent in men in the symptomatic group. However, no significant differences in condylar position were found in asymptomatic subjects according to gender. Conclusion. This study showed no apparent association between condylar positioning and clinical findings in TMD patients. PMID:26681944

  14. 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

  15. Restrain of bone growth by estrogen-mimetic peptide-1 (EMP-1): a micro-computed tomographic study.

    PubMed

    Kasher, Roni; Bajayo, Alon; Gabet, Yankel; Nevo, Nava; Fridkin, Mati; Katchalski-Katzir, Ephraim; Kohen, Fortune; Bab, Itai

    2009-06-01

    Estrogen has a key role in the regulation of skeletal growth and maintenance of bone mass. Recently, we developed peptides having estrogen-like activity as potential estrogen-based new drugs. The aim of the present study was to evaluate the influence of long-term administration of the most efficacious of these peptides, the hexapeptide EMP-1 (VSWFFE), on bone mass and development. EMP-1 was injected daily to ovariectomized (OVX) and intact young, sexually mature female mice for 10 weeks. Whole femora, including the cartilaginous growth plates were analyzed by micro-computed tomography (microCT). We found that peptide EMP-1 restrains bone growth in OVX mice: it inhibited dramatically bone longitudinal growth (40%), and decreased femoral diaphyseal diameter. Peptide EMP-1 had no effect on bone growth in normal mice, and did not influence the OVX-induced bone loss. We then developed a new microCT methodology to evaluate uncalcified and calcified growth plate parameters. In the OVX mice, peptide EMP-1 reduced volume and thickness of the uncalcified growth plate, a possible cause for the inhibition of bone longitudinal growth. Peptide EMP-1 may be used as a lead compound for the development of drugs to treat acromegalic patients.

  16. Association of intra-abdominal pathologies and vascular anomalies with infrarenal aortic aneurysm: a computed tomographic study.

    PubMed

    Matano, R; Gennaro, M; Mohan, C; Ascer, E

    1993-02-01

    The prevalence of potentially significant intra-abdominal pathologies or vascular anomalies in candidates for infrarenal aortic aneurysm repair remains unclear. This study retrospectively reviewed 130 consecutive patients with aortic aneurysms (4.5-10.0 cm in largest diameter) who had undergone contrast-enhanced abdominal computed tomography. The overall incidence of potentially significant pathologies was 31.5%. Gallstones were detected in 25 patients (19.2%), adrenal masses in six (4.6%), pancreatic tumors in two (1.5%), renal stones in two (1.5%), liver metastases in one (0.8%), retroperitoneal lymphoma in one (0.8%) and left gastric artery aneurysm in one (0.8%). Other pathologies included renal cysts in 42 patients (32.3%), colonic diverticulosis in nine (6.9%) and hepatic cysts in three (2.3%). Major vascular anomalies were encountered in only three of the 130 patients (2.3%) and these included two with a left-sided inferior vena cava and one case of retroaortic left renal vein. This study emphasizes the high incidence of potentially significant intra-abdominal pathologies and the low incidence of major vascular anomalies associated with infrarenal aortic aneurysm. The impact of such findings on the management of aortic aneurysms is discussed.

  17. 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

  18. Comparison of electrocardiographic-gated technetium-99m sestamibi single-photon emission computed tomographic imaging and rest-redistribution thallium-201 in the prediction of myocardial viability.

    PubMed

    Duncan, B H; Ahlberg, A W; Levine, M G; McGill, C C; Mann, A; White, M P; Mather, J F; Waters, D D; Heller, G V

    2000-03-15

    Although the combined assessment of perfusion and function using rest electrocardiographic (ECG)-gated technetium-99m (Tc-99m) sestamibi single-photon emission computed tomographic (SPECT) imaging has been shown to improve sensitivity and accuracy over perfusion alone in the prediction of myocardial viability, no data are available comparing this technique with rest-redistribution thallium-201. Thirty patients with coronary artery disease and left ventricular dysfunction (ejection fraction < or = 40%) underwent rest-redistribution thallium-201 and rest ECG-gated Tc-99m sestamibi SPECT imaging before revascularization and rest ECG-gated Tc-99m sestamibi SPECT imaging at 1 or 6 weeks after revascularization. All thallium-201 and Tc-99m sestamibi images were interpreted by a consensus agreement of 3 experienced readers without knowledge of patient identity or time of imaging with Tc-99m sestamibi (before or after revascularization) using a 17-segment model. Concordance between techniques for the prediction of viability was 89% (kappa 0.556 +/- 0.109). With rest-redistribution thallium-201, sensitivity, specificity, positive predictive value, negative predictive value, and predictive accuracy were 95%, 59%, 88%, 78%, and 86%, respectively. With rest ECG-gated Tc-99m sestamibi SPECT imaging, sensitivity, specificity, positive predictive value, negative predictive value, and predictive accuracy were 96%, 55%, 87%, 80%, and 86%, respectively (p = NS vs rest-redistribution thallium-201). Although both techniques are comparable for detecting viable myocardium, rest ECG-gated Tc-99m sestamibi SPECT imaging allows direct assessment of both myocardial perfusion and ventricular function, which may be clinically useful in patients who require assessment of myocardial viability.

  19. Endoscopic and computed tomographic evaluation of influence of nasal septal deviation on lateral wall of nose and its relation to sinus diseases.

    PubMed

    Poorey, V K; Gupta, Neha

    2014-09-01

    To correlate symptoms of deviated nasal septum (DNS) and chronic rhinosinusitis with the findings of nasal endoscopy and computed tomographic (CT) imaging. To evaluate the influence of degree of septal angle deviation on the severity of lateral nasal wall abnormalities. A prospective study was conducted on 67 patients with clinical evidence of DNS and chronic sinusitis attending ENT OPD between January 2012 and September 2013. All these patients underwent nasal endoscopy and CT scan PNS coronal sections. Direction and degree of DNS was recorded. Range of sinus mucosal thickening on CT scan films was also recorded. Chronic sinusitis is common in the age group between 21 and 40 years (50.74 %) with male preponderance (55.22 %), chief symptoms being nasal obstruction (86.56 %), headache (73.13 %) and nasal discharge (52.23 %). Left sided DNS is more common (64.17 %). Most of the patients have moderate DNS, i.e. 6°-10° (56.7 %), followed by severe (22.4 %) and then mild (20.9 %). DNS results in compensatory structural changes in the turbinates and/or lateral nasal wall which causes ostiomeatal complex (OMC) obstruction resulting in sinusitis. Contralateral concha bullosa and ethmoid bulla prominence was noted. Maxillary sinus is most commonly affected sinus (73.13 %). Patients with increasing septal angles were associated with a higher incidence of maxillary sinus mucosal changes (p < 0.05). Present study reemphasized the concept that septal deviation causes obstruction at OMC which results in an increased incidence and severity of bilateral chronic sinus disease.

  20. Use of a Diagnostic Score to Prioritize Computed Tomographic (CT) Imaging for Patients Suspected of Ischemic Stroke Who May Benefit from Thrombolytic Therapy

    PubMed Central

    Bots, Michiel L.; Selvarajah, Sharmini; Kappelle, L. Jaap; Abdul Aziz, Zariah; Sidek, Norsima Nazifah; Vaartjes, Ilonca

    2016-01-01

    Background A shortage of computed tomographic (CT) machines in low and middle income countries often results in delayed CT imaging for patients suspected of a stroke. Yet, time constraint is one of the most important aspects for patients with an ischemic stroke to benefit from thrombolytic therapy. We set out to assess whether application of the Siriraj Stroke Score is able to assist physicians in prioritizing patients with a high probability of having an ischemic stroke for urgent CT imaging. Methods From the Malaysian National Neurology Registry, we selected patients aged 18 years and over with clinical features suggesting of a stroke, who arrived in the hospital 4.5 hours or less from ictus. The prioritization of receiving CT imaging was left to the discretion of the treating physician. We applied the Siriraj Stroke Score to all patients, refitted the score and defined a cut-off value to best distinguish an ischemic stroke from a hemorrhagic stroke. Results Of the 2176 patients included, 73% had an ischemic stroke. Only 33% of the ischemic stroke patients had CT imaging within 4.5 hours. The median door-to-scan time for these patients was 4 hours (IQR: 1;16). With the recalibrated score, it would have been possible to prioritize 95% (95% CI: 94%–96%) of patients with an ischemic stroke for urgent CT imaging. Conclusions In settings where CT imaging capacity is limited, we propose the use of the Siriraj Stroke Score to prioritize patients with a probable ischemic stroke for urgent CT imaging. PMID:27768752

  1. Impact of Clinical Guideline Recommendations on the Application of Coronary Computed Tomographic Angiography in Patients with Suspected Stable Coronary Artery Disease

    PubMed Central

    Zhou, Jia; Yang, Jun-Jie; Yang, Xia; Chen, Zhi-Ye; He, Bai; Du, Luo-Shan; Chen, Yun-Dai

    2016-01-01

    Background: Coronary computed tomographic angiography (CCTA) has been widely used in patients who are at intermediate risk for having stable coronary artery disease (SCAD), and 2013 European Society of Cardiology Guidelines on the Management of SCAD (2013G) recommended the appropriate application of CCTA. However, 2013G has not been subjected to systematic analyses for subsequent impact on clinical practice. Methods: A total of 5320 patients suspected with SCAD were enrolled and scheduled for CCTA from March 2013 to September 2014. For each patient, pretest probability of SCAD was calculated according to updated Diamond-Forrester model (UDFM). Appropriate CCTA or appropriate stress test was determined as described in the 2013G. A generalized estimating equation model was used to determine the trends in the half-monthly rate of appropriate CCTA. Results: Overall, only 61.37% of patients received appropriate CCTA, and there was insignificant change over time (P = 0.8701). The application of CCTA in patients who should have had a stress test accounted for most of the inappropriate CCTA before (22.29%) or after (19.98%) the publication of the 2013G. In all patients or any subgroup, no significant change in the adjusted half-monthly rate of appropriate CCTA was found after the publication of the 2013G (odds ratio, 1.002; 95% confidence interval, 0.982–1.021; P = 0.8678). Conclusions: These findings suggest that the 2013G have not, to date, been fully incorporated into clinical practice, and the clinical utilization of CCTA remains unreasonable to some extent. PMID:26830982

  2. Computed tomographic study of the posterior condylar angle in arthritic knees: its use in the rotational positioning of the femoral implant of total knee prostheses.

    PubMed

    Boisgard, S; Moreau, P-E; Descamps, S; Courtalhiac, C; Silbert, H; Moreel, P; Michel, J-L; Levai, J-P

    2003-01-01

    The epicondylar axis is a reliable reference to check the rotation of the femoral implant in total knee prostheses (TKPs). However, during the operation it seems easier to use the posterior condylar axis as a landmark. The angle between these two axes is called the posterior condylar angle (PCA). The aim of this study was to measure the PCA in arthritic knees to assess the reliability of the posterior condylar axis as a reference for the control of the rotation of the femoral implant and to look for correlation with other radiological measurements. This prospective study consisted of 103 arthritic knees (81 varus, 22 valgus) before a TKP had been done in 103 patients (75 women, 28 men). The assessment of the PCA was made by computed tomographic scanning (CT). The HKA, HKS and HKT angles were measured on the pangonogram. The posterior condylar axis was internally rotated with respect to the epicondylar axis. The average value for all the patients was 2.65 degrees degrees with a range from 0 degrees to 7 degrees. The PCA was significantly increased in the valgus knees. There was no correlation between the angles on the pangonogram and the posterior condylar axis. While the preoperative assessment of the PCA by CT scanning is reliable, the results obtained indicate the marked variability in its value. If one wishes to use the posterior condylar axis as a guide for rotation, it is therefore necessary to assess the PCA for each patient using adjustable jigs according to the value obtained. No measurement on standard radiographs allowed an extrapolation of the value of the PCA, and CT scanning seems to be the preferable radiological examination.

  3. 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.

  4. Incremental value of diagonal earlobe crease to the Diamond-Forrester classification in estimating the probability of significant coronary artery disease determined by computed tomographic angiography.

    PubMed

    Shmilovich, Haim; Cheng, Victor Y; Nakazato, Ryo; Smith, Thomas W; Otaki, Yuka; Nakanishi, Rine; Paz, William; Pimentel, Raymond T; Berman, Daniel S; Rajani, Ronak

    2014-12-01

    The Diamond-Forrester (DF) algorithm overestimates the likelihood of significant coronary artery disease (≥50% stenosis, CAD50). The aim of the present study was to evaluate whether the addition of a diagonal earlobe crease (DELC) enhances the predictive ability of DF to detect CAD50 by coronary computed tomographic angiography (CTA). We evaluated 430 patients referred for CTA for symptoms, cardiovascular risk factors, and CAD50 likelihood using DF. Observers blinded to CTA findings evaluated the presence of DELC. The diagnostic accuracy and relation of DF, DELC, and DF + DELC for predicting CAD50 in patients with chest pain were evaluated using receiver operating characteristics curve (area under curve) analyses and multivariate logistic regression analyses. In 199 patients with chest pain, the sensitivity and specificity for CAD50 were 96% and 20% for DF (AUC 0.59, p = 0.59), 91% and 32% for DELC (AUC 0.62, p = 0.03), and 91% and 41% for DF + DELC (AUC 0.66, p = 0.004). On multivariate analyses DELC was the only independent predictor of CAD50 (odds ratio 3.6, 95% confidence interval 1 to 12.9, p = 0.048). DF + DELC increased the predictive ability to detect CAD50 above cardiovascular risk factors (odds ratio 5.6, 95% confidence interval 1.6 to 19.8, p = 0.007). In patients with chest pain, the presence of DELC is related to CAD50 beyond DF. A combined variable of DF + DELC provides superior discriminatory ability for detecting CAD50 than either method alone.

  5. 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

  6. 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

  7. The use of computed tomographic three-dimensional reconstructions to develop instructional models for equine pelvic ultrasonography.

    PubMed

    Whitcomb, Mary Beth; Doval, John; Peters, Jason

    2011-01-01

    Ultrasonography has gained increased utility to diagnose pelvic fractures in horses; however, internal pelvic contours can be difficult to appreciate from external palpable landmarks. We developed three-dimensional (3D) simulations of the pelvic ultrasonographic examination to assist with translation of pelvic contours into two-dimensional (2D) images. Contiguous 1mm transverse computed tomography (CT) images were acquired through an equine femur and hemipelvis using a single slice helical scanner. 3D surface models were created using a DICOM reader and imported into a 3D modeling and animation program. The bone models were combined with a purchased 3D horse model and the skin made translucent to visualize pelvic surface contours. 3D models of ultrasound transducers were made from reference photos, and a thin sector shape was created to depict the ultrasound beam. Ultrasonographic examinations were simulated by moving transducers on the skin surface and rectally to produce images of pelvic structures. Camera angles were manipulated to best illustrate the transducer-beam-bone interface. Fractures were created in multiple configurations. Animations were exported as QuickTime movie files for use in presentations coupled with corresponding ultrasound videoclips. 3D models provide a link between ultrasonographic technique and image generation by depicting the interaction of the transducer, ultrasound beam, and structure of interest. The horse model was important to facilitate understanding of the location of pelvic structures relative to the skin surface. While CT acquisition time was brief, manipulation within the 3D software program was time intensive. Results were worthwhile from an instructional standpoint based on user feedback. PMID:21699617

  8. 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.

  9. 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

    2016-01-01

    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

  10. 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

  11. 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

  12. Cone beam computed tomographic analyses of alveolar bone anatomy at the maxillary anterior region in Chinese adults.

    PubMed

    Zhou, Zhixuan; Chen, Wu; Shen, Ming; Sun, Chao; Li, Jun; Chen, Ning

    2014-11-01

    To provide an anatomical basis for clinical implant esthetics, we evaluated the morphology of the nasopalatine canal (NPC) and analyzed labial and interproximal bone anatomy at the maxillary anterior region. We sought to investigate the effect of maxillary protrusion and tooth labiolingual inclination on labial bone anatomy in Chinese adults. Three dimensional (3D) images were reconstructed using cone-beam computed tomography (CBCT) images from 80 Chinese subjects and by SimPlant 11.04. The dimensions of the NPC, the thickness and profile of the labial bone, the width and height of the interproximal bone, angle sella-nasion-subspinale (SNA) and angle upper central incisor-nasion,subspinale (U1-NA) were measured. The incisive foramen of the NPC was markedly wider than its nasal foramen. The dimension of its labial bone wall demonstrated an increasing width from the crestal to apical measurements. The labial bone at the maxillary anterior region was rather thin, especially at 3 mm below the cemento-enamel junction (CEJ) and the mid-root level; the profile of the labial bone was more curved at the central incisor, and the interproximal bone became wider and shorter posteriorly. There were significant relationships between maxillary protrusion and labial bone profile, tooth labiolingual inclination and labial bone thickness (P < 0.02). To achieve optimal esthetic outcome of implant, bone augmentation is necessary at the maxillary anterior region. For immediate or early placement at the maxillary anterior region, the implant should be located palatally to reduce labial bone resorption and marginal recession; its apex should be angulated palatally to avoid labial perforation at the apical region. To protect the NPC, implants at the central incisor region should be placed away from NPC. PMID:25469120

  13. 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

  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. 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.

  16. 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.

  17. Evaluation of Lip Cant Change by 2-Jaw Surgery in Class III Asymmetry Cases Using Three-Dimensional Facial Scan in Conjunction With Computed Tomographic Images.

    PubMed

    Ko, Jeong-Min; Choi, Jin-Young; Baek, Seung-Hak

    2015-06-01

    The aim of our study was to evaluate the effect of cant correction in the anterior (AMXTOP) and posterior maxillary transverse occlusal planes (PMXTOP) on the change in lip cant (LC) using three-dimensional facial scan (FS) in conjunction with computed tomographic (CT) images. Thirty-five class III asymmetry patients treated with 2-jaw surgery were selected. Three-dimensional CT and three-dimensional FS images were taken before (T1) and after orthognathic surgery (T2). After obtaining the same head orientation between 2 images, bracket slot midpoints of the maxillary right and left canines as well as the first molars, point A, point B, and menton on three-dimensional CT images and the right and left lip commissures on three-dimensional FS images were located. Linear and angular variables of AMXTOP, PMXTOP, and LC were measured and statistically analyzed. At the T1 stage, linear and angular LC showed significant correlations with linear and angular cant of AMXTOP and PMXTOP, as well as menton deviation (all P < 0.001). During T1 to T2, significant linear and angular cant corrections were observed: ΔAMXTOP (1.3 mm, 1.9 degrees), ΔPMXTOP (1.9 mm, 1.7 degrees), and ΔLC (1.5 mm, 1.8 degrees) (all P < 0.001). Although angular change ratios of ΔLC/ΔAMXTOP and ΔLC/ΔPMXTOP did not exhibit a significant difference (1.0 vs 0.7), linear change ratio of ΔLC/ΔAMXTOP was higher than that of ΔLC/ΔPMXTOP (3.0 vs 0.5, P < 0.05). The vertical change in commissures was related to that in the maxillary right and left canines or maxillary right and left first molars and the extent of mandibular setback (all P < 0.01). To conclude, the use of three-dimensional FS images in conjunction with three-dimensional CT can provide more accurate information for changes in AMXTOP, PMXTOP, and LC.

  18. 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.

  19. Tomographic scanning imager.

    PubMed

    Hovland, Harald

    2009-07-01

    In tomographic scanning (TOSCA) imaging, light from a scene is focused onto a reticle mask using conical scan optics, and collected on a single element detector. Alternatively, one or several detectors replace the reticle. Tomographic processing techniques are then applied to the one-dimensional signal to reproduce a two-dimensional image. The TOSCA technique is presented in detail, including its mathematical foundations and some of its limitations. It is shown how TOSCA imaging can be used in a multispectral configuration, and compares well with more conventional alternatives both in simplicity and performance. Examples of image reconstruction using TOSCA techniques are shown. PMID:19582052

  20. Effect of Donepezil on Wernicke Aphasia After Bilateral Middle Cerebral Artery Infarction: Subtraction Analysis of Brain F-18 Fluorodeoxyglucose Positron Emission Tomographic Images.

    PubMed

    Yoon, Seo Yeon; Kim, Je-Kyung; An, Young-Sil; Kim, Yong Wook

    2015-01-01

    Aphasia is one of the most common neurologic deficits occurring after stroke. Although the speech-language therapy is a mainstream option for poststroke aphasia, pharmacotherapy is recently being tried to modulate different neurotransmitter systems. However, the efficacy of those treatments is still controversial. We present a case of a 53-year-old female patient with Wernicke aphasia, after the old infarction in the territory of left middle cerebral artery for 8 years and the recent infarction in the right middle cerebral artery for 4 months. On the initial evaluation, the Aphasia Quotient in Korean version of the Western Aphasia Battery was 25.6 of 100. Baseline brain F-18 fluorodeoxyglucose positron emission tomographic images demonstrated a decreased cerebral metabolism in the left temporoparietal area and right temporal lobe. Donepezil hydrochloride, a reversible acetylcholinesterase inhibitor, was orally administered 5 mg/d for 6 weeks after the initial evaluation and was increased to 10 mg/d for the following 6 weeks. After the donepezil treatment, the patient showed improvement in language function, scoring 51.0 of 100 on Aphasia Quotient. A subtraction analysis of the brain F-18 fluorodeoxyglucose positron emission tomographic images after donepezil medication demonstrated increased uptake in both middle temporal gyri, extended to the occipital area and the left cerebellum. Thus, we suggest that donepezil can be an effective therapeutic choice for the treatment of Wernicke aphasia.

  1. Guided bone regeneration in standardized calvarial defects using beta-tricalcium phosphate and collagen membrane: a real-time in vivo micro-computed tomographic experiment in rats.

    PubMed

    Ramalingam, Sundar; Al-Rasheed, Abdulaziz; ArRejaie, Aws; Nooh, Nasser; Al-Kindi, Mohammed; Al-Hezaimi, Khalid

    2016-05-01

    Guided bone regeneration (GBR) procedures using graft materials have been used for reconstruction of osseous defects. The aim of the present in vivo micro-computed tomographic (µCT) and histologic study was to assess in real time the bone regeneration at GBR sites in standardized experimental calvarial defects (diameter 3.3 mm) using β-tricalcium phosphate (β-TCP) with and without collagen membrane (CM). A single full-thickness calvarial defect was created on the left parietal bone in young female Wistar albino rats (n = 30) weighing approximately 300 g and aged about 6 weeks. The animals were randomly divided into three groups for treatment, based on calvarial defect filling material: (1) control group (n = 10); (2) β-TCP + CM group (n = 10); (3) β-TCP group (n = 10). Real-time in vivo µCT analyses were performed immediately after surgery and at 2, 4, 6 and 10 weeks to determine the volume and mineral density of the newly formed bone (BVNFB, MDNFB) and remaining β-TCP particles (VRBP, MDRBP). The animals were killed at 10 weeks and calvarial specimens were evaluated histologically. In the control group, MDNFB increased significantly at 6 weeks (0.32 ± 0.002 g/mm(3), P < 0.01) compared to that at baseline. In β-TCP + CM group, BVNFB (1.10 ± 0.12 mm(3), P < 0.01) and MDNFB (0.13 ± 0.02 g/mm(3), P < 0.01) significantly increased at the 4th week than baseline. In the β-TCP group, BVNFB (1.13 ± 0.12 mm(3), P < 0.01) and MDNFB (0.14 ± 0.01 g/mm(3), P < 0.01) significantly increased at 6 weeks compared to that at baseline. Significant reduction in VRBP was neither seen in the β-TCP + CM group nor in the β-TCP group. While in the β-TCP + CM group MDRBP was reduced significantly at 6 weeks (0.44 ± 0.9 g/mm(3), P < 0.01) from baseline (0.98 ± 0.03 g/mm(3)), similar significant reduction in MDRBP from baseline (0.92 ± 0.07 g/mm(3)) was seen only at 10 weeks (0.45 ± 0.06 g/mm(3), P < 0.05) in the β-TCP group. Histologic findings at 10 weeks revealed

  2. Multiscale intensity homogeneity transformation method and its application to computer-aided detection of pulmonary embolism in computed tomographic pulmonary angiography (CTPA)

    NASA Astrophysics Data System (ADS)

    Guo, Yanhui; Zhou, Chuan; Chan, Heang-Ping; Wei, Jun; Chughtai, Aamer; Sundaram, Baskaran; Hadjiiski, Lubomir M.; Patel, Smita; Kazerooni, Ella A.

    2013-04-01

    A 3D multiscale intensity homogeneity transformation (MIHT) method was developed to reduce false positives (FPs) in our previously developed CAD system for pulmonary embolism (PE) detection. In MIHT, the voxel intensity of a PE candidate region was transformed to an intensity homogeneity value (IHV) with respect to the local median intensity. The IHVs were calculated in multiscales (MIHVs) to measure the intensity homogeneity, taking into account vessels of different sizes and different degrees of occlusion. Seven new features including the entropy, gradient, and moments that characterized the intensity distributions of the candidate regions were derived from the MIHVs and combined with the previously designed features that described the shape and intensity of PE candidates for the training of a linear classifier to reduce the FPs. 59 CTPA PE cases were collected from our patient files (UM set) with IRB approval and 69 cases from the PIOPED II data set with access permission. 595 and 800 PEs were identified as reference standard by experienced thoracic radiologists in the UM and PIOPED set, respectively. FROC analysis was used for performance evaluation. Compared with our previous CAD system, at a test sensitivity of 80%, the new method reduced the FP rate from 18.9 to 14.1/scan for the PIOPED set when the classifier was trained with the UM set and from 22.6 to 16.0/scan vice versa. The improvement was statistically significant (p<0.05) by JAFROC analysis. This study demonstrated that the MIHT method is effective in reducing FPs and improving the performance of the CAD system.

  3. 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.

  4. Computational Aeroacoustic Analysis System Development

    NASA Technical Reports Server (NTRS)

    Hadid, A.; Lin, W.; Ascoli, E.; Barson, S.; Sindir, M.

    2001-01-01

    Many industrial and commercial products operate in a dynamic flow environment and the aerodynamically generated noise has become a very important factor in the design of these products. In light of the importance in characterizing this dynamic environment, Rocketdyne has initiated a multiyear effort to develop an advanced general-purpose Computational Aeroacoustic Analysis System (CAAS) to address these issues. This system will provide a high fidelity predictive capability for aeroacoustic design and analysis. The numerical platform is able to provide high temporal and spatial accuracy that is required for aeroacoustic calculations through the development of a high order spectral element numerical algorithm. The analysis system is integrated with well-established CAE tools, such as a graphical user interface (GUI) through PATRAN, to provide cost-effective access to all of the necessary tools. These include preprocessing (geometry import, grid generation and boundary condition specification), code set up (problem specification, user parameter definition, etc.), and postprocessing. The purpose of the present paper is to assess the feasibility of such a system and to demonstrate the efficiency and accuracy of the numerical algorithm through numerical examples. Computations of vortex shedding noise were carried out in the context of a two-dimensional low Mach number turbulent flow past a square cylinder. The computational aeroacoustic approach that is used in CAAS relies on coupling a base flow solver to the acoustic solver throughout a computational cycle. The unsteady fluid motion, which is responsible for both the generation and propagation of acoustic waves, is calculated using a high order flow solver. The results of the flow field are then passed to the acoustic solver through an interpolator to map the field values into the acoustic grid. The acoustic field, which is governed by the linearized Euler equations, is then calculated using the flow results computed

  5. CGAT: computational genomics analysis toolkit.

    PubMed

    Sims, David; Ilott, Nicholas E; Sansom, Stephen N; Sudbery, Ian M; Johnson, Jethro S; Fawcett, Katherine A; Berlanga-Taylor, Antonio J; Luna-Valero, Sebastian; Ponting, Chris P; Heger, Andreas

    2014-05-01

    Computational genomics seeks to draw biological inferences from genomic datasets, often by integrating and contextualizing next-generation sequencing data. CGAT provides an extensive suite of tools designed to assist in the analysis of genome scale data from a range of standard file formats. The toolkit enables filtering, comparison, conversion, summarization and annotation of genomic intervals, gene sets and sequences. The tools can both be run from the Unix command line and installed into visual workflow builders, such as Galaxy.

  6. 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

  7. 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.

  8. 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

  9. 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

    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.

  10. 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.

  11. Tomographic applications of wavelets in passive nondestructive assay of radioactive waste

    NASA Astrophysics Data System (ADS)

    Weems, Lance David

    1998-07-01

    An economically reliable and technologically feasible methodology for assaying radioactive waste is essential for properly disposing of newly generated and legacy radioactive waste. The present research has investigated, developed, and integrated tomographic applications of wavelets into the present segmented gamma scanning (SGS) measurement methodology used for passive nondestructive assay of radioactive waste. The SGS measurement methodology was specifically developed to nondestructively measure the radionuclide content within only low-density, homogeneously drum-packaged scrap and waste using the techniques of gamma-ray spectrometry. A result of this research has been the Tomographic Segmented Gamma Scanner (TSGS) system. This TSGS system supplements a rotation-averaged SGS measurement system with tomographic gamma scanning (TGS) capability that can specifically take into account the effects of larger density and radionuclide distribution non-uniformities when present. This TSGS system allows the throughput to remain high with a less detailed but faster rotation-averaged segment measurement of homogenous radioactive waste, while the TGS capability provides a more detailed but slower spatial radionuclide measurement for assaying heterogeneous radionuclide waste as necessary. Within the experimental part of this research, (1) the tomographic experimental feasibility was established, (2) a TSGS system integrated calibration was designed, (3) collimation sampling problems were studied, (4) SGS and TGS modality-specific comparisons were shown, and finally, (5) the TSGS system precision was measured. An investigation of the applications of wavelets in computerized tomography has lead to the development of a radionuclide computerized tomography (RCT) algorithm able to accurately calculate the measured radionuclide content within heterogeneously packaged scrap and waste. Within the computational part of this research, (1) the optimization of a relaxation parameter that

  12. 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.

  13. 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.

  14. Textual Analysis with Computers: Tests of Bell Laboratories' Computer Software.

    ERIC Educational Resources Information Center

    Kiefer, Kathleen E.; Smith, Charles R.

    1983-01-01

    Concludes that textual analysis with computers intrigues college writers and speeds learning of editing skills by offering immediate, reliable, and consistent attention to surface features of their prose. (HOD)

  15. 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

  16. 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.

  17. 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

  18. Micro-computed tomographic assessment of quality of obturation in the apical third with continuous wave vertical compaction and single match taper sized cone obturation techniques.

    PubMed

    Alshehri, Mohammed; Alamri, Hadi M; Alshwaimi, Emad; Kujan, Omar

    2016-07-01

    The aim of the present micro-computed tomography (Micro-CT) analysis was to compare the quality of obturation in the apical third of the root with the warm vertical compaction (WVC) and single matching taper sized cone (SMTSC) techniques. Mesial roots of 16 freshly extracted mandibular first molar teeth (with a total of 32 canals) were used. Canals in each mesial root were shaped to a size F3 Protaper and were randomly assigned to either continuous wave vertical compaction or single match tapered size cone technique. Volume of voids and gaps in the obturated roots were measured using micro-CT scanning at 1, 3, and 5 mm from the apex of the root. There was no statistically significant difference in the volume of voids measured at 1 mm (p > 0.05), 3 mm (p > 0.05) and 5 mm (p > 0.05) filled with either WVC and SMTSC techniques. The quality of obturation in the apical third of the root with the WVC and SMTSC techniques is comparable. SCANNING 38:352-356, 2016. © 2015 Wiley Periodicals, Inc.

  19. Cone beam computed tomographic evaluation of two access cavity designs and instrumentation on the thickness of peri-cervical dentin in mandibular anterior teeth

    PubMed Central

    Varghese, Vinny Sara; George, John V.; Mathew, Sylvia; Nagaraja, Shruthi; Indiresha, H. N.; Madhu, K. S.

    2016-01-01

    Background and Objectives: The aim of the study was to determine the effect of two access cavity designs on the peri-cervical dentin thickness before and after instrumentation using cone beam computed tomography (CBCT). Materials and Methods: Sixty mandibular anterior teeth were divided into two groups of thirty teeth each: Group I: conventional access cavity preparation, where access was prepared just above the cingulum and Group II: incisal access cavity preparation, where access was prepared in proximity to the incisal edge. CBCT scans were taken preoperatively, following access cavity preparation and post instrumentation. 200 μm thick slices were obtained 4mm apical and coronal to the cemento-enamel junction. The peri-cervical dentin thickness was calculated on the facial, lingual, mesial, and distal for all the three obtained scans. Results: The analysis showed that access cavity preparation and instrumentation resulted in a significant loss of tooth structure in Group I on all surfaces, but in Group II, there was a significant loss of tooth structure only in the mesial, lingual, and distal surfaces (P < 0.05). Conclusion: Incisal access cavity preparation resulted in lesser loss of dentin in the peri-cervical region.

  20. Cone beam computed tomographic evaluation of two access cavity designs and instrumentation on the thickness of peri-cervical dentin in mandibular anterior teeth

    PubMed Central

    Varghese, Vinny Sara; George, John V.; Mathew, Sylvia; Nagaraja, Shruthi; Indiresha, H. N.; Madhu, K. S.

    2016-01-01

    Background and Objectives: The aim of the study was to determine the effect of two access cavity designs on the peri-cervical dentin thickness before and after instrumentation using cone beam computed tomography (CBCT). Materials and Methods: Sixty mandibular anterior teeth were divided into two groups of thirty teeth each: Group I: conventional access cavity preparation, where access was prepared just above the cingulum and Group II: incisal access cavity preparation, where access was prepared in proximity to the incisal edge. CBCT scans were taken preoperatively, following access cavity preparation and post instrumentation. 200 μm thick slices were obtained 4mm apical and coronal to the cemento-enamel junction. The peri-cervical dentin thickness was calculated on the facial, lingual, mesial, and distal for all the three obtained scans. Results: The analysis showed that access cavity preparation and instrumentation resulted in a significant loss of tooth structure in Group I on all surfaces, but in Group II, there was a significant loss of tooth structure only in the mesial, lingual, and distal surfaces (P < 0.05). Conclusion: Incisal access cavity preparation resulted in lesser loss of dentin in the peri-cervical region. PMID:27656065

  1. 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.

  2. 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…

  3. 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.

  4. Regularization in radio tomographic imaging

    NASA Astrophysics Data System (ADS)

    Sundaram, Ramakrishnan; Martin, Richard; Anderson, Christopher

    2013-05-01

    This paper demonstrates methods to select and apply regularization to the linear least-squares model formulation of the radio tomographic imaging (RTI) problem. Typically, the RTI inverse problem of image reconstruction is ill-conditioned due to the extremely small singular values of the weight matrix which relates the link signal strengths to the voxel locations of the obstruction. Regularization is included to offset the non-invertible nature of the weight matrix by adding a regularization term such as the matrix approximation of derivatives in each dimension based on the difference operator. This operation yields a smooth least-squares solution for the measured data by suppressing the high energy or noise terms in the derivative of the image. Traditionally, a scalar weighting factor of the regularization matrix is identified by trial and error (adhoc) to yield the best fit of the solution to the data without either excessive smoothing or ringing oscillations at the boundaries of the obstruction. This paper proposes new scalar and vector regularization methods that are automatically computed based on the weight matrix. Evidence of the effectiveness of these methods compared to the preset scalar regularization method is presented for stationary and moving obstructions in an RTI wireless sensor network. The variation of the mean square reconstruction error as a function of the scalar regularization is calculated for known obstructions in the network. The vector regularization procedure based on selective updates to the singular values of the weight matrix attains the lowest mean square error.

  5. 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

    Iselin, Lukas D; Ramawat, Sunil; Hanratty, Brian; Klammer, Georg; Stavrou, Peter

    2015-05-01

    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.

  6. 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.

  7. 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.

  8. 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.

  9. Error Analysis In Computational Elastodynamics

    NASA Astrophysics Data System (ADS)

    Mukherjee, Somenath; Jafarali, P.; Prathap, Gangan

    The Finite Element Method (FEM) is the mathematical tool of the engineers and scientists to determine approximate solutions, in a discretised sense, of the concerned differential equations, which are not always amenable to closed form solutions. In this presentation, the mathematical aspects of this powerful computational tool as applied to the field of elastodynamics have been highlighted, using the first principles of virtual work and energy conservation.

  10. 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.

  11. 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

  12. 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…

  13. FT3D: three-dimensional Fourier analysis on small Unix workstations for electron microscopy and tomographic studies.

    PubMed

    Lanzavecchia, S; Bellon, P L; Tosoni, L

    1993-12-01

    FT3D is a self-contained package of tools for three-dimensional Fourier analysis, written in the C language for Unix workstations. It can evaluate direct transforms of three-dimensional real functions, inverse transforms, auto- and cross-correlations and spectra. The library has been developed to support three-dimensional reconstructions of biological structures from projections obtained in the electron microscope. This paper discusses some features of the library, which has been implemented in such a way as to profit from the resources of modern workstations. A table of elapsed times for jobs of different dimensions with different RAM buffers is reported for the particular hardware used in the authors' laboratory.

  14. Automated detection of pulmonary embolism (PE) in computed tomographic pulmonary angiographic (CTPA) images: multiscale hierachical expectation-maximization segmentation of vessels and PEs

    NASA Astrophysics Data System (ADS)

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

    2007-03-01

    CT pulmonary angiography (CTPA) has been reported to be an effective means for clinical diagnosis of pulmonary embolism (PE). We are developing a computer-aided detection (CAD) system to assist radiologist in PE detection in CTPA images. 3D multiscale filters in combination with a newly designed response function derived from the eigenvalues of Hessian matrices is used to enhance vascular structures including the vessel bifurcations and suppress non-vessel structures such as the lymphoid tissues surrounding the vessels. A hierarchical EM estimation is then used to segment the vessels by extracting the high response voxels at each scale. The segmented vessels are pre-screened for suspicious PE areas using a second adaptive multiscale EM estimation. A rule-based false positive (FP) reduction method was designed to identify the true PEs based on the features of PE and vessels. 43 CTPA scans were used as an independent test set to evaluate the performance of PE detection. Experienced chest radiologists identified the PE locations which were used as "gold standard". 435 PEs were identified in the artery branches, of which 172 and 263 were subsegmental and proximal to the subsegmental, respectively. The computer-detected volume was considered true positive (TP) when it overlapped with 10% or more of the gold standard PE volume. Our preliminary test results show that, at an average of 33 and 24 FPs/case, the sensitivities of our PE detection method were 81% and 78%, respectively, for proximal PEs, and 79% and 73%, respectively, for subsegmental PEs. The study demonstrates the feasibility that the automated method can identify PE accurately on CTPA images. Further study is underway to improve the sensitivity and reduce the FPs.

  15. Radiological Safety Analysis Computer Program

    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

  16. 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

  17. 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…

  18. 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.

  19. Relation between QT dispersion and adenosine triphosphate stress thallium-201 single-photon emission computed tomographic imaging for detecting myocardial ischemia and scar.

    PubMed

    Teragawa, H; Hirao, H; Muraoka, Y; Yamagata, T; Matsuura, H; Kajiyama, G

    1999-04-15

    It is not known if QT dispersion is useful for detecting coronary artery disease. We investigated whether QT dispersion at baseline and during adenosine triphosphate (ATP) infusion correlate with the imaging patterns obtained from ATP stress thallium-201 single-photon emission computed tomography (ATP-SPECT). QT dispersion was determined in 169 patients who underwent ATP-SPECT from 12-lead electrocardiograms obtained at baseline and 3 minutes after the beginning of ATP infusion. Based on the results of ATP-SPECT, patients were divided into 4 groups: normal (n = 55), ischemia (n = 38), ischemia and scar (n = 42), and scar (n = 34). Baseline QT dispersions (mean +/- SD) in the normal, ischemia, ischemia and scar, and scar groups were 48 +/- 15, 50 +/- 17, 69 +/- 25, and 70 +/- 24 ms, respectively. Baseline QT dispersion was significantly greater in the groups with myocardial scar. QT dispersions during ATP infusion were 43 +/- 16, 63 +/- 20, 76 +/- 20, and 62 +/- 25 ms in the normal, ischemia, ischemia and scar, and scar groups, respectively. QT dispersion increased with ATP infusion in patients with myocardial ischemia. QT dispersion at baseline and during ATP infusion correlated with the ATP-SPECT imaging pattern. These findings suggest that baseline QT dispersion and ATP-induced changes in QT dispersion may help detect the presence of myocardial ischemia and scar. PMID:10215275

  20. Three-dimensional spiral computed tomographic cysto-urethrography for post-traumatic complex posterior urethral strictures associated with urethral-rectal fistula.

    PubMed

    Sa, Ying Long; Xu, Yue Min; Feng, Chao; Ye, Xu Xiao; Song, Lu Jie

    2013-01-01

    To evaluate the value of three-dimensional spiral computed tomography/cysto-urethrography (CTCUG) in diagnosing posterior urethral strictures associated with urethrorectal fistulas (URF). Between June 2008 and March 2012, 38 patients with posterior urethral strictures associated with URFs were examined by CTCUG, retrograde urethrography (RUG) and cysto-urethrography (CUG). Urethral reconstruction was undertaken and URFs were surgically repaired in all patients. The length of the urethral defect, location and size of URFs were recorded. Data from radiological examinations were compared with surgical findings. No statistically significant difference was found in the length of stricture measured using CTCUG (4.31 ± 2.28 cm) or conventional urethrography (4.02 ± 3.12 cm; p > 0.05), However, the accuracy in determining the location of the stricture was higher with CTCUG (93.12%) than with conventional urethrography (70.59%; p < 0.05). CTCUG identified URFs in all 38 patients (100%), whereas URFs were only observed in 27 patients (71%) using conventional urethrography. In conclusion, CTCUG was more accurate, safer and provided more details of URFs and urethral defects than conventional urethrography in patients with posterior urethral strictures associated with URFs.

  1. Coronary Computed Tomographic Angiography at 80 kVp and Knowledge-Based Iterative Model Reconstruction Is Non-Inferior to that at 100 kVp with Iterative Reconstruction

    PubMed Central

    Lee, Joohee; Park, Chul Hwan; Oh, Chi Suk; Han, Kyunghwa; Kim, Tae Hoon

    2016-01-01

    The aims of this study were to compare the image noise and quality of coronary computed tomographic angiography (CCTA) at 80 kVp with knowledge-based iterative model reconstruction (IMR) to those of CCTA at 100 kVp with hybrid iterative reconstruction (IR), and to evaluate the feasibility of a low-dose radiation protocol with IMR. Thirty subjects who underwent prospective electrocardiogram-gating CCTA at 80 kVp, 150 mAs, and IMR (Group A), and 30 subjects with 100 kVp, 150 mAs, and hybrid IR (Group B) were retrospectively enrolled after sample-size calculation. A BMI of less than 25 kg/m2 was required for inclusion. The attenuation value and image noise of CCTA were measured and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated at the proximal right coronary artery and left main coronary artery. The image noise was analyzed using a non-inferiority test. The CCTA images were qualitatively evaluated using a four-point scale. The radiation dose was significantly lower in Group A than Group B (0.69 ± 0.08 mSv vs. 1.39 ± 0.15 mSv, p < 0.001). The attenuation values were higher in Group A than Group B (p < 0.001). The SNR and CNR in Group A were higher than those of Group B. The image noise of Group A was non-inferior to that of Group B. Qualitative image quality of Group A was better than that of Group B (3.6 vs. 3.4, p = 0.017). CCTA at 80 kVp with IMR could reduce the radiation dose by about 50%, with non-inferior image noise and image quality than those of CCTA at 100 kVp with hybrid IR. PMID:27658197

  2. Association of total and computed tomographic measures of regional adiposity with incident cancer risk: a prospective population-based study of older adults

    PubMed Central

    Murphy, Rachel A.; Bureyko, Taylor F.; Miljkovic, Iva; Cauley, Jane A.; Satterfield, Suzanne; Hue, Trisha F.; Klepin, Heidi D.; Cummings, Steven R.; Newman, Anne B.; Harris, Tamara B.

    2014-01-01

    Obesity is associated with increased risk of many types of cancer. Less is known regarding associations between adipose depots and cancer risk. We aimed to explore relationships between adipose depots, risk of cancer and obesity-related cancer (per NCI definition) in participants initially aged 70–79 without prevalent cancer (1,179 men, 1,340 women), and followed for incident cancer for 13 years. Measures included body mass index (BMI), total adipose tissue from dual-energy X-ray absorptiometry and computed tomography measures: visceral adipose tissue (VAT), abdominal subcutaneous adipose tissue (SAT), thigh intermuscular adipose tissue and thigh muscle attenuation (Hounsfield Unit, HU), low HU indicates fatty infiltration. Hazard ratios (HR) and 95% confidence intervals (CIs) were estimated by Cox proportional hazards regression adjusted for demographics, lifestyle variables and medical conditions. During follow-up 617 participants developed cancer of which 224 were obesity-related cancers. Total adipose tissue and VAT were positively associated with cancer risk among women (HR 1.14, 95% CI 1.01–1.30 per SD increase, HR 1.15, 95% CI 1.02–1.30 per SD increase). There were no associations with cancer risk among men. Total adipose tissue was positively associated with obesity-related cancer risk among women (HR 1.23, 95% CI 1.03–1.46 per SD increase). VAT was positively associated with obesity-related cancer risk among men (HR 1.30, 95% CI 1.06–1.60 per SD increase) and remained associated even with adjustment for BMI (HR 1.40, 95% CI 1.08–1.82 per SD increase). These findings provide insight into relationships between specific adipose depots and cancer risk and suggest differential relationships among men and women. PMID:24869972

  3. Better Diagnosis of Functionally Significant Intermediate Sized Narrowings Using Intravascular Ultrasound-Minimal Lumen Area and Coronary Computed Tomographic Angiography-Based Myocardial Segmentation.

    PubMed

    Kang, Soo-Jin; Yang, Dong Hyun; Kweon, Jihoon; Kim, Young-Hak; Lee, June-Goo; Jung, Joonho; Kim, Namkug; Mintz, Gary S; Kang, Joon-Won; Lim, Tae-Hwan; Park, Seong-Wook

    2016-04-15

    Lesion morphology poorly predicts functional significance of intermediate coronary artery stenosis. The aim of this study was to determine whether a coronary artery-based myocardial segmentation method that quantifies subtended myocardium can improve the diagnostic accuracy of intravascular ultrasound (IVUS)-derived parameters for detecting ischemia-producing lesions. Coronary computed tomography angiography, IVUS, and fractional flow reserve (FFR) data were analyzed in 101 non-left main lesions (20% to 80% angiographic stenosis). Using the coronary artery-based myocardial segmentation method, total left ventricular myocardial volume (Vtotal), myocardial volume subtended by the stenotic coronary segment (Vsub), and Vratio (the ratio of the Vsub to the Vtotal) were assessed. Both Vsub >30.7 cm(3) and Vratio >25.4% were determinants of FFR ≤0.75 (area under the curve = 0.696 and 0.744). Overall, an IVUS-measured minimum lumen area (IVUS-MLA) ≤2.83 mm(2) predicted FFR ≤0.75 with a sensitivity 88% and specificity 73%. Among lesions with IVUS-MLA ≤2.83 mm(2) and FFR >0.75, 89% showed Vsub <30.7 cm(3). In 50 lesions with Vsub >30.7 cm(3), an IVUS-MLA ≤2.85 mm(2) predicted FFR ≤0.75 with sensitivity 85%, specificity 92%, positive predictive value 92%, and negative predictive value 85%. Conversely, in 51 lesions with a Vsub ≤30.7 cm(3), IVUS-MLA ≤2.67 mm(2) showed sensitivity 100%, specificity 69%, positive predictive value 38%, and negative predictive value 100% for predicting FFR ≤0.75. Body surface area, reference lumen diameter, and vessel area had modest correlations with Vsub. In those lesion subsets, IVUS-MLA ≈2.8 mm(2) accurately predicted an FFR ≤0.75, whereas the clinical relevance of assessing and treating lesions with a smaller myocardial territory may be limited (ClinicalTrials.gov number NCT1696006).

  4. Computational analysis of ramjet engine inlet interaction

    NASA Technical Reports Server (NTRS)

    Duncan, Beverly; Thomas, Scott

    1992-01-01

    A computational analysis of a ramjet engine at Mach 3.5 has been conducted and compared to results obtained experimentally. This study focuses on the behavior of the inlet both with and without combustor backpressure. Increased backpressure results in separation of the body side boundary layer and a resultant static pressure rise in the inlet throat region. The computational results compare well with the experimental data for static pressure distribution through the engine, inlet throat flow profiles, and mass capture. The computational analysis slightly underpredicts the thickness of the engine body surface boundary layer and the extent of the interaction caused by backpressure; however, the interaction is observed at approximately the same level of backpressure both experimentally and computationally. This study demonstrates the ability of two different Navier-Stokes codes, namely RPLUS and PARC, to calculate the flow features of this ramjet engine and to provide more detailed information on the process of inlet interaction and unstart.

  5. MTX data acquisition and analysis computer network

    SciTech Connect

    Butner, D.N.; Casper, T.A.; Brown, M.D.; Drlik, M.; Meyer, W.H.; Moller, J.M. )

    1990-10-01

    For the MTX experiment, we use a network of computers for plasma diagnostic data acquisition and analysis. This multivendor network employs VMS, UNIX, and BASIC based computers connected in a local area Ethernet network. Some of the data is acquired directly into a VAX/VMS computer cluster over a fiber-optic serial CAMAC highway. Several HP-Unix workstations and HP-BASIC instrument control computers acquire and analyze data for the more data intensive or specialized diagnostics. The VAX/VMS system is used for global analysis of the data and serves as the central data archiving and retrieval manager. Shot synchronization and control of data flow are implemented by task-to-task message passing using our interprocess communication system. The system has been in operation during our initial MTX tokamak and FEL experiments; it has operated reliably with data rates typically in the range of 5 Mbytes/shot without limiting the experimental shot rate.

  6. 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.

  7. 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

  8. 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.

  9. The computer in shell stability analysis

    NASA Technical Reports Server (NTRS)

    Almroth, B. O.; Starnes, J. H., Jr.

    1975-01-01

    Some examples in which the high-speed computer has been used to improve the static stability analysis capability for general shells are examined. The fundamental concepts of static stability are reviewed with emphasis on the differences between linear bifurcation buckling and nonlinear collapse. The analysis is limited to the stability of conservative systems. Three examples are considered. The problem of cylinders subjected to bending loads is used as an example to illustrate that a simple structure can have a sufficiently complicated nonlinear behavior to require a computer analysis for accurate results. An analysis of the problems involved in the modeling of stiffening elements in plate and shell structures illustrates the necessity that the analyst recognizes all important deformation modes. The stability analysis of the Skylab structure indicates the size of problems that can be solved with current state-of-the-art capability.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Computed tomographic localization of pelvic hydatid disease.

    PubMed

    Kotoulas, G; Gouliamos, A; Kalovidouris, A; Vlahos, L; Papavasiliou, C

    1990-01-01

    Nine patients with history of hydatid disease have been examined by CT. Localization of the hydatid cysts in the pelvis was established by anatomical criteria. Occasionally, the transverse plane can be confusing for the precise localization of a lesion. A central location, close to the boundaries of the bladder and rectum, can define peritoneal location. Further posterolateral retrovesical location can be considered retroperitoneal. Using these criteria, 8 cysts were situated within the peritoneum and 1 within the retroperitoneum.

  15. Large posterior abdominal masses: computed tomographic localization.

    PubMed

    Engel, I A; Auh, Y H; Rubenstein, W A; Whalen, J P; Kazam, E

    1983-10-01

    Large posterior abdominal masses, particularly those in the right upper abdomen, may be difficult to localize correctly into the peritoneal or retroperitoneal compartments. The following signs were found to be reliable CT indicators of retroperitoneal location: obliteration of the perinephric fat outlining the psoas muscle; lateral displacement of the fat outlining the posterior right lobe of the liver; rotation of the intrahepatic portal veins to the left; anterior displacement of the inferior vena cava and renal veins; and anterior displacement of the ascending colon, descending duodenum, or pancreatic head.

  16. Varied computed tomographic appearance of intracranial cryptococcosis

    SciTech Connect

    Cornell, S.H.; Jacoby, C.G.

    1982-06-01

    CT findings in 12 cases of intracranial cryptococcal infection were reviewed. Five patients had a normal scan. Seven patients had communicating or noncommunicating hydrocephalus. Additional findings included meningeal opacification, cerebritis, abscess, and granuloma. Although not specific for cryptococcosis, the CT scan is helpful for evaluating and following the status of the ventricles, subarachnoid spaces, and meninges.

  17. 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.

  18. 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.

  19. 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...

  20. 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

  1. 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.

  2. Enhancement of terahertz reflection tomographic imaging by interference cancellation between layers.

    PubMed

    Park, Hochong; Son, Joo-Hiuk; Ahn, Chang-Beom

    2016-04-01

    This paper proposes a method to enhance terahertz reflection tomographic imaging by interference cancellation between layers. When the gap between layers is small, the signal reflected on the upper layer interferes with that on the lower layer, which degrades the quality of the reconstructed tomographic image in the lower layer. The proposed method estimates the upper-layer reflection signal by system modeling, which is then eliminated from the acquired signal. In this way, it can provide the correct lower-layer reflection signal, thereby improving the quality of the lower-layer tomographic image. The performance of the proposed method was confirmed using computer simulation data and real terahertz reflection data.

  3. 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.

  4. Tomographic Neutron Imaging using SIRT

    SciTech Connect

    Gregor, Jens; FINNEY, Charles E A; Toops, Todd J

    2013-01-01

    Neutron imaging is complementary to x-ray imaging in that materials such as water and plastic are highly attenuating while material such as metal is nearly transparent. We showcase tomographic imaging of a diesel particulate filter. Reconstruction is done using a modified version of SIRT called PSIRT. We expand on previous work and introduce Tikhonov regularization. We show that near-optimal relaxation can still be achieved. The algorithmic ideas apply to cone beam x-ray CT and other inverse problems.

  5. SPICE benchmark for global tomographic methods

    NASA Astrophysics Data System (ADS)

    Qin, Yilong; Capdeville, Yann; Maupin, Valerie; Montagner, Jean-Paul; Lebedev, Sergei; Beucler, Eric

    2008-11-01

    The existing global tomographic methods result in different models due to different parametrization, scale resolution and theoretical approach. To test how current imaging techniques are limited by approximations in theory and by the inadequacy of data quality and coverage, it is necessary to perform a global-scale benchmark to understand the resolving properties of each specific imaging algorithm. In the framework of the Seismic wave Propagation and Imaging in Complex media: a European network (SPICE) project, it was decided to perform a benchmark experiment of global inversion algorithms. First, a preliminary benchmark with a simple isotropic model is carried out to check the feasibility in terms of acquisition geometry and numerical accuracy. Then, to fully validate tomographic schemes with a challenging synthetic data set, we constructed one complex anisotropic global model, which is characterized by 21 elastic constants and includes 3-D heterogeneities in velocity, anisotropy (radial and azimuthal anisotropy), attenuation, density, as well as surface topography and bathymetry. The intermediate-period (>32 s), high fidelity anisotropic modelling was performed by using state-of-the-art anisotropic anelastic modelling code, that is, coupled spectral element method (CSEM), on modern massively parallel computing resources. The benchmark data set consists of 29 events and three-component seismograms are recorded by 256 stations. Because of the limitation of the available computing power, synthetic seismograms have a minimum period of 32 s and a length of 10 500 s. The inversion of the benchmark data set demonstrates several well-known problems of classical surface wave tomography, such as the importance of crustal correction to recover the shallow structures, the loss of resolution with depth, the smearing effect, both horizontal and vertical, the inaccuracy of amplitude of isotropic S-wave velocity variation, the difficulty of retrieving the magnitude of azimuthal

  6. 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.

  7. 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

  8. Comparison of Bayesian and classical reconstructions of tomographic gamma scanning for assay of nuclear materials

    SciTech Connect

    Burr, T.L.; Mercer, D.J.; Prettyman, T.H.

    1998-12-01

    Tomographic gamma scanning has been used to assay special nuclear material for the past several years. Field experience suggests that the data analysis techniques can significantly affect the assay uncertainty. For example, a positive bias has been observed for low-activity samples. Recent attempts to reduce the bias without unacceptable increase in variance have taken a non-Bayesian approach. This paper will compare some of these non-Bayesian approaches to a Bayesian approach which is a modification of an approach used in photon emission computed tomography. The Bayesian approach is both more computationally demanding and more satisfying, though the choice of the prior probability for the distribution of nuclear material can impact the analysis. Assay results for scaled-down versions of the full-dimensioned problem will be presented for several methods and cases.

  9. 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.

  10. 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.

  11. A proposed-standard format to represent and distribute tomographic models and other earth spatial data

    NASA Astrophysics Data System (ADS)

    Postpischl, L.; Morelli, A.; Danecek, P.

    2009-04-01

    ) computational meshes. This approach can exploit the capabilities of the web browser as a computing platform: a series of in-page quick tools for comparative analysis between models will be presented, as well as visualisation techniques for tomographic layers in Google Maps and Google Earth. We are working on tools for conversion into common scientific format like netCDF, to allow easy visualisation in GEON-IDV or gmt.

  12. 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.

  13. 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.

  14. Computer analysis of HIV epitope sequences

    SciTech Connect

    Gupta, G.; Myers, G.

    1990-01-01

    Phylogenetic tree analysis provide us with important general information regarding the extent and rate of HIV variation. Currently we are attempting to extend computer analysis and modeling to the V3 loop of the type 2 virus and its simian homologues, especially in light of the prominent role the latter will play in animal model studies. Moreover, it might be possible to attack the slightly similar V4 loop by this approach. However, the strategy relies very heavily upon natural'' information and constraints, thus there exist severe limitations upon the general applicability, in addition to uncertainties with regard to long-range residue interactions. 5 refs., 3 figs.

  15. 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

  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. 76 FR 60939 - Metal Fatigue Analysis Performed by Computer Software

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-30

    ... COMMISSION Metal Fatigue Analysis Performed by Computer Software AGENCY: Nuclear Regulatory Commission... applicants' analyses and methodologies using the computer software package, WESTEMS TM , to demonstrate... by Computer Software Addressees All holders of, and applicants for, a power reactor operating...

  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. Semiconductor Device Analysis on Personal Computers

    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. Simple optical computing device for chemical analysis

    NASA Astrophysics Data System (ADS)

    Soyemi, Olusola O.; Zhang, Lixia; Eastwood, DeLyle; Li, Hongli; Gemperline, Paul J.; Myrick, Michael L.

    2001-05-01

    Multivariate Optical Computing (MOC) devices have the potential of greatly simplifying as well as reducing the cost of applying the mathematics of multivariate regression to problems of chemical analysis in the real world. These devices utilize special optical interference coatings known as multivariate optical elements (MOEs) that are encoded with pre-determined spectroscopic patterns to selectively quantify a chemical species of interest in the presence of other interfering species. A T-format prototype of the first optical computing device is presented utilizing a multilayer MOE consisting of alternating layers of two metal oxide films (Nb2O5 and SiO2) on a BK-7 glass substrate. The device was tested by using it to quantify copper uroporphyrin in a quaternary mixture consisting of uroporphyrin (freebase), tin uroporphyrin, nickel uroporphyrin, and copper uroporphyrin. A standard error of prediction (SEP) of 0.86(mu) M was obtained for copper uroporphyrin.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. Computer analysis of mammography phantom images (CAMPI)

    NASA Astrophysics Data System (ADS)

    Chakraborty, Dev P.

    1997-05-01

    Computer analysis of mammography phantom images (CAMPI) is a method for objective and precise measurements of phantom image quality in mammography. This investigation applied CAMPI methodology to the Fischer Mammotest Stereotactic Digital Biopsy machine. Images of an American College of Radiology phantom centered on the largest two microcalcification groups were obtained on this machine under a variety of x-ray conditions. Analyses of the images revealed that the precise behavior of the CAMPI measures could be understood from basic imaging physics principles. We conclude that CAMPI is sensitive to subtle image quality changes and can perform accurate evaluations of images, especially of directly acquired digital images.

  6. 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.

  7. 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.

  8. 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.

  9. Analysis of Ventricular Function by Computed Tomography

    PubMed Central

    Rizvi, Asim; Deaño, Roderick C.; Bachman, Daniel P.; Xiong, Guanglei; Min, James K.; Truong, Quynh A.

    2014-01-01

    The assessment of ventricular function, cardiac chamber dimensions and ventricular mass is fundamental for clinical diagnosis, risk assessment, therapeutic decisions, and prognosis in patients with cardiac disease. Although cardiac computed tomography (CT) is a noninvasive imaging technique often used for the assessment of coronary artery disease, it can also be utilized to obtain important data about left and right ventricular function and morphology. In this review, we will discuss the clinical indications for the use of cardiac CT for ventricular analysis, review the evidence on the assessment of ventricular function compared to existing imaging modalities such cardiac MRI and echocardiography, provide a typical cardiac CT protocol for image acquisition and post-processing for ventricular analysis, and provide step-by-step instructions to acquire multiplanar cardiac views for ventricular assessment from the standard axial, coronal, and sagittal planes. Furthermore, both qualitative and quantitative assessments of ventricular function as well as sample reporting are detailed. PMID:25576407

  10. Evaluation of a multicore-optimized implementation for tomographic reconstruction.

    PubMed

    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

  11. 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.

  12. Computational Analysis of Human Blood Flow

    NASA Astrophysics Data System (ADS)

    Panta, Yogendra; Marie, Hazel; Harvey, Mark

    2009-11-01

    Fluid flow modeling with commercially available computational fluid dynamics (CFD) software is widely used to visualize and predict physical phenomena related to various biological systems. In this presentation, a typical human aorta model was analyzed assuming the blood flow as laminar with complaint cardiac muscle wall boundaries. FLUENT, a commercially available finite volume software, coupled with Solidworks, a modeling software, was employed for the preprocessing, simulation and postprocessing of all the models.The analysis mainly consists of a fluid-dynamics analysis including a calculation of the velocity field and pressure distribution in the blood and a mechanical analysis of the deformation of the tissue and artery in terms of wall shear stress. A number of other models e.g. T branches, angle shaped were previously analyzed and compared their results for consistency for similar boundary conditions. The velocities, pressures and wall shear stress distributions achieved in all models were as expected given the similar boundary conditions. The three dimensional time dependent analysis of blood flow accounting the effect of body forces with a complaint boundary was also performed.

  13. Methods of the computer-aided statistical analysis of microcircuits

    NASA Astrophysics Data System (ADS)

    Beliakov, Iu. N.; Kurmaev, F. A.; Batalov, B. V.

    Methods that are currently used for the computer-aided statistical analysis of microcircuits at the design stage are summarized. In particular, attention is given to methods for solving problems in statistical analysis, statistical planning, and factorial model synthesis by means of irregular experimental design. Efficient ways of reducing the computer time required for statistical analysis and numerical methods of microcircuit analysis are proposed. The discussion also covers various aspects of the organization of computer-aided microcircuit modeling and analysis systems.

  14. Experimental tomographic scanning (TOSCA) imagers

    NASA Astrophysics Data System (ADS)

    Hovland, H.

    2014-06-01

    The tomographic scanner (TOSCA) detects signals using line detectors scanning a scene at regularly distributed angles. These line scan signals are then processed to reconstruct 2-dimensional images. In the simplest form, a 1-axis rotating conical scan optics scans across a simple patterned reticle, the signal collection being done with a single pixel detector. Experimental mono- and multispectral cameras using this approach are demonstrated under varying illumination conditions. Of particular interest is the TOSCA system's ability to handle and compensate for light sources modulated with a frequency higher than that of the frame rate. We also demonstrate for the first time a TOSCA imager operating in the infrared region. The device is put together using 3D-printed key parts and low cost optical components, leading to a very economical infrared camera.

  15. 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.

  16. 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.

  17. 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.

  18. Distributed Design and Analysis of Computer Experiments

    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

  19. Computational System For Rapid CFD Analysis In Engineering

    NASA Technical Reports Server (NTRS)

    Barson, Steven L.; Ascoli, Edward P.; Decroix, Michelle E.; Sindir, Munir M.

    1995-01-01

    Computational system comprising modular hardware and software sub-systems developed to accelerate and facilitate use of techniques of computational fluid dynamics (CFD) in engineering environment. Addresses integration of all aspects of CFD analysis process, including definition of hardware surfaces, generation of computational grids, CFD flow solution, and postprocessing. Incorporates interfaces for integration of all hardware and software tools needed to perform complete CFD analysis. Includes tools for efficient definition of flow geometry, generation of computational grids, computation of flows on grids, and postprocessing of flow data. System accepts geometric input from any of three basic sources: computer-aided design (CAD), computer-aided engineering (CAE), or definition by user.

  20. 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.

  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. 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.

  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. 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.

  5. Can cloud computing benefit health services? - a SWOT analysis.

    PubMed

    Kuo, Mu-Hsing; Kushniruk, Andre; Borycki, Elizabeth

    2011-01-01

    In this paper, we discuss cloud computing, the current state of cloud computing in healthcare, and the challenges and opportunities of adopting cloud computing in healthcare. A Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis was used to evaluate the feasibility of adopting this computing model in healthcare. The paper concludes that cloud computing could have huge benefits for healthcare but there are a number of issues that will need to be addressed before its widespread use in healthcare. PMID:21893777

  6. Can cloud computing benefit health services? - a SWOT analysis.

    PubMed

    Kuo, Mu-Hsing; Kushniruk, Andre; Borycki, Elizabeth

    2011-01-01

    In this paper, we discuss cloud computing, the current state of cloud computing in healthcare, and the challenges and opportunities of adopting cloud computing in healthcare. A Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis was used to evaluate the feasibility of adopting this computing model in healthcare. The paper concludes that cloud computing could have huge benefits for healthcare but there are a number of issues that will need to be addressed before its widespread use in healthcare.

  7. A computational design system for rapid CFD analysis

    NASA Technical Reports Server (NTRS)

    Ascoli, E. P.; Barson, S. L.; Decroix, M. E.; Sindir, Munir M.

    1992-01-01

    A computation design system (CDS) is described in which these tools are integrated in a modular fashion. This CDS ties together four key areas of computational analysis: description of geometry; grid generation; computational codes; and postprocessing. Integration of improved computational fluid dynamics (CFD) analysis tools through integration with the CDS has made a significant positive impact in the use of CFD for engineering design problems. Complex geometries are now analyzed on a frequent basis and with greater ease.

  8. Schlieren sequence analysis using computer vision

    NASA Astrophysics Data System (ADS)

    Smith, Nathanial Timothy

    Computer vision-based methods are proposed for extraction and measurement of flow structures of interest in schlieren video. As schlieren data has increased with faster frame rates, we are faced with thousands of images to analyze. This presents an opportunity to study global flow structures over time that may not be evident from surface measurements. A degree of automation is desirable to extract flow structures and features to give information on their behavior through the sequence. Using an interdisciplinary approach, the analysis of large schlieren data is recast as a computer vision problem. The double-cone schlieren sequence is used as a testbed for the methodology; it is unique in that it contains 5,000 images, complex phenomena, and is feature rich. Oblique structures such as shock waves and shear layers are common in schlieren images. A vision-based methodology is used to provide an estimate of oblique structure angles through the unsteady sequence. The methodology has been applied to a complex flowfield with multiple shocks. A converged detection success rate between 94% and 97% for these structures is obtained. The modified curvature scale space is used to define features at salient points on shock contours. A challenge in developing methods for feature extraction in schlieren images is the reconciliation of existing techniques with features of interest to an aerodynamicist. Domain-specific knowledge of physics must therefore be incorporated into the definition and detection phases. Known location and physically possible structure representations form a knowledge base that provides a unique feature definition and extraction. Model tip location and the motion of a shock intersection across several thousand frames are identified, localized, and tracked. Images are parsed into physically meaningful labels using segmentation. Using this representation, it is shown that in the double-cone flowfield, the dominant unsteady motion is associated with large scale

  9. Deflection tomographic reconstruction of a complex flow field from incomplete projection data

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; He, Yan; Song, Yang; He, Anzhi

    2009-11-01

    Tomographic techniques are used for the investigation of complex flow fields by means of deflectometric methods. In this experiment, a modified algebraic reconstruction technique (ART) was applied to moiré deflection tomography. The algorithm was derived from the basic deflection formula and the deflection angles were used directly in iteration, which is completely different from the conventional ARTs with integral calculation that are commonly used in deflection tomography. A smoothing scheme was employed to improve the reconstruction under ill-posed conditions. The reconstruction technique was tested using simulated data for incompleteness conditions similar to those found in the experimental data. The complex density field with an opaque object in a supersonic wind tunnel was reconstructed from limited view angle projections, and the experimental reconstruction was then compared with the result obtained from the computational fluid dynamic analysis. The following paper details the experiment and discusses some measurement errors that occurred in the process.

  10. 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

  11. 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

  12. 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.

  13. 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)

  14. 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.

  15. 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).

  16. Computational analysis of DOD drop formation

    NASA Astrophysics Data System (ADS)

    Xu, Qi; Basaran, Osman

    2007-11-01

    A fundamental theoretical understanding of drop-on-demand (DOD) ink jet printing remains weak despite the widespread use of the method in practical applications for two decades. To overcome this deficiency, a computational analysis is carried out to simulate the formation of liquid drops of incompressible Newtonian fluids from a nozzle by imposing a transient flow rate upstream of the nozzle exit. The dynamics are studied as functions of the Ohnesorge number Oh (viscous/surface tension force) and the Weber number We (inertial/surface tension force). For a common ink forming from a nozzle of 10 micrometer radius, Oh=0.1. For this typical case, a phase or operability diagram is developed that shows that three regimes of operation are possible. In the first regime, where We is low, breakup does not occur, and drops remain pendant from the nozzle and undergo time periodic oscillations. Thus, the simulations show that sufficient fluid inertia, or a sufficiently large We, is required if a DOD drop is to form, in accord with intuition. At high We, two regimes exist. In the first of these two regimes, DOD drops do form but have negative velocities, i.e. they would move toward the nozzle upon breakup, which is undesirable. In the second breakup regime, not only are DOD drops formed but they do so with positive velocities.

  17. 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

    Basudan, Amani; Babay, Nadir; Ramalingam, Sundar; Nooh, Nasser; Al-Kindi, 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

  18. 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.

  19. 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.

  20. 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.

  1. 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…

  2. 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…

  3. 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.

  4. Roentgen stereophotogrammetric analysis using computer-based image-analysis.

    PubMed

    Ostgaard, S E; Gottlieb, L; Toksvig-Larsen, S; Lebech, A; Talbot, A; Lund, B

    1997-09-01

    The two-dimensional position of markers in radiographs for Roentgen Stereophotogrammetric Analysis (RSA) is usually determined using a measuring table. The purpose of this study was to evaluate the reproducibility and the accuracy of a new RSA system using digitized radiographs and image-processing algorithms to determine the marker position in the radiographs. Four double-RSA examinations of a phantom and 18 RSA examinations from six patients included in different RSA-studies of knee prostheses were used to test the reproducibility and the accuracy of the system. The radiographs were scanned at 600 dpi resolution and 256 gray levels. The center of each of the tantalum-markers in the radiographs was calculated by the computer program from the contour of the marker with the use of an edge-detection software algorithm after the marker was identified on a PC monitor. The study showed that computer-based image analysis can be used in RSA-examinations. The advantages of using image-processing software in RSA are that the marker positions are determined in an objective manner, and that there is no need for a systematic manual identification of all the markers on the radiograph before the actual measurement.

  5. Toward a micrometer resolution x-ray tomographic microscope

    NASA Astrophysics Data System (ADS)

    Silver, Michael D.

    1995-09-01

    Near-micrometer resolution, three-dimensional computed tomographic images were made of a test object using the hard x-ray microscope developed by the National Institute of Standards and Technology (NIST). The microscope uses a cooled CCD camera with direct conversion of the incident x rays by a 512 multiplied by 512 chip with 19 micrometer by 19 micrometer cells. Magnification by a factor of 20 is achieved using asymmetric Bragg diffraction from a pair of silicon crystals. The imaging system is designed for samples of the order of 0.50 mm diameter by 0.50 mm height. From beamline X23A3 at the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory (BNL) 8.17 keV x rays were used. Two hundred, 512 multiplied by 512 two-dimensional projections were collected every 0.9 degrees about the test object using the NIST microscope. The projections were digitized and sent to a computer for volume tomographic reconstruction by a parallel-beam, convolution-backprojection algorithm into a 5123 image with (1 micrometer)3 voxels. The test object consisted of glass and nickel microspheres with distributions from about 4 t 40 micrometer (glass) or to 24 micrometer (nickel) diameters suspended in epoxy in order to demonstrate near one micrometer resolution in all three dimensions and probe contrast sensitivity. The effect and interplay of photon statistics and energy, and sample composition, density and size on tomographic performance are discussed as are resolution limitations and image artifacts from Fresnel diffraction.

  6. Calculating Path-Dependent Travel Time Prediction Variance and Covariance for the SALSA3D Global Tomographic P-Velocity Model with a Distributed Parallel Multi-Core Computer

    NASA Astrophysics Data System (ADS)

    Hipp, J. R.; Encarnacao, A.; Ballard, S.; Young, C. J.; Phillips, W. S.; Begnaud, M. L.

    2011-12-01

    Recently our combined SNL-LANL research team has succeeded in developing a global, seamless 3D tomographic P-velocity model (SALSA3D) that provides superior first P travel time predictions at both regional and teleseismic distances. However, given the variable data quality and uneven data sampling associated with this type of model, it is essential that there be a means to calculate high-quality estimates of the path-dependent variance and covariance associated with the predicted travel times of ray paths through the model. In this paper, we show a methodology for accomplishing this by exploiting the full model covariance matrix. Our model has on the order of 1/2 million nodes, so the challenge in calculating the covariance matrix is formidable: 0.9 TB storage for 1/2 of a symmetric matrix, necessitating an Out-Of-Core (OOC) blocked matrix solution technique. With our approach the tomography matrix (G which includes Tikhonov regularization terms) is multiplied by its transpose (GTG) and written in a blocked sub-matrix fashion. We employ a distributed parallel solution paradigm that solves for (GTG)-1 by assigning blocks to individual processing nodes for matrix decomposition update and scaling operations. We first find the Cholesky decomposition of GTG which is subsequently inverted. Next, we employ OOC matrix multiply methods to calculate the model covariance matrix from (GTG)-1 and an assumed data covariance matrix. Given the model covariance matrix we solve for the travel-time covariance associated with arbitrary ray-paths by integrating the model covariance along both ray paths. Setting the paths equal gives variance for that path. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  7. 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

  8. Frequency modulation television analysis: Threshold impulse analysis. [with computer program

    NASA Technical Reports Server (NTRS)

    Hodge, W. H.

    1973-01-01

    A computer program is developed to calculate the FM threshold impulse rates as a function of the carrier-to-noise ratio for a specified FM system. The system parameters and a vector of 1024 integers, representing the probability density of the modulating voltage, are required as input parameters. The computer program is utilized to calculate threshold impulse rates for twenty-four sets of measured probability data supplied by NASA and for sinusoidal and Gaussian modulating waveforms. As a result of the analysis several conclusions are drawn: (1) The use of preemphasis in an FM television system improves the threshold by reducing the impulse rate. (2) Sinusoidal modulation produces a total impulse rate which is a practical upper bound for the impulse rates of TV signals providing the same peak deviations. (3) As the moment of the FM spectrum about the center frequency of the predetection filter increases, the impulse rate tends to increase. (4) A spectrum having an expected frequency above (below) the center frequency of the predetection filter produces a higher negative (positive) than positive (negative) impulse rate.

  9. 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

  10. Tomographic methods in flow diagnostics

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.

    1993-01-01

    This report presents a viewpoint of tomography that should be well adapted to currently available optical measurement technology as well as the needs of computational and experimental fluid dynamists. The goals in mind are to record data with the fastest optical array sensors; process the data with the fastest parallel processing technology available for small computers; and generate results for both experimental and theoretical data. An in-depth example treats interferometric data as it might be recorded in an aeronautics test facility, but the results are applicable whenever fluid properties are to be measured or applied from projections of those properties. The paper discusses both computed and neural net calibration tomography. The report also contains an overview of key definitions and computational methods, key references, computational problems such as ill-posedness, artifacts, missing data, and some possible and current research topics.

  11. Computational Analysis of SAXS Data Acquisition

    PubMed Central

    Dong, Hui; Kim, Jin Seob

    2015-01-01

    Abstract 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

  12. 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).

  13. Steering in spin tomographic probability representation

    NASA Astrophysics Data System (ADS)

    Man'ko, V. I.; Markovich, L. A.

    2016-09-01

    The steering property known for two-qubit state in terms of specific inequalities for the correlation function is translated for the state of qudit with the spin j = 3 / 2. Since most steering detection inequalities are based on the correlation functions we introduce analogs of such functions for the single qudit systems. The tomographic probability representation for the qudit states is applied. The connection between the correlation function in the two-qubit system and the single qudit is presented in an integral form with an intertwining kernel calculated explicitly in tomographic probability terms.

  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. 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.

  16. 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.

  17. A computational analysis for amino acid adsorption

    NASA Astrophysics Data System (ADS)

    Owens, Brandon E.; Riemann, Andreas

    2014-06-01

    In this study we have systematically investigated the effects of surface configuration and molecular state for the adsorption of methionine (C5H11NO2S) on a graphite surface using two model force fields, AMBER 3 and MM +. Computational results were compared with experimental results.

  18. Conversation Analysis of Computer-Mediated Communication

    ERIC Educational Resources Information Center

    Gonzalez-Lloret, Marta

    2011-01-01

    The potential of computer-mediated communication (CMC) for language learning resides mainly in the possibility that learners have to engage with other speakers of the language, including L1 speakers. The inclusion of CMC in the L2 classroom provides an opportunity for students to utilize authentic language in real interaction, rather than the more…

  19. Protocluster discovery in tomographic Ly α forest flux maps

    NASA Astrophysics Data System (ADS)

    Stark, Casey W.; White, Martin; Lee, Khee-Gan; Hennawi, Joseph F.

    2015-10-01

    We present a new method of finding protoclusters using tomographic maps of Ly α forest flux. We review our method of creating tomographic flux maps and discuss our new high-performance implementation, which makes large reconstructions computationally feasible. Using a large N-body simulation, we illustrate how protoclusters create large-scale flux decrements, roughly 10 h-1 Mpc across, and how we can use this signal to find them in flux maps. We test the performance of our protocluster finding method by running it on the ideal, noiseless map and tomographic reconstructions from mock surveys, and comparing to the halo catalogue. Using the noiseless map, we find protocluster candidates with about 90 per cent purity, and recover about 75 per cent of the protoclusters that form massive clusters (>3 × 1014 h-1 M⊙). We construct mock surveys similar to the ongoing COSMOS Lyman-Alpha Mapping And Tomography Observations survey. While the existing data have an average sightline separation of 2.3 h-1 Mpc, we test separations of 2-6 h-1 Mpc to see what can be tolerated for our application. Using reconstructed maps from small separation mock surveys, the protocluster candidate purity and completeness are very close to what was found in the noiseless case. As the sightline separation increases, the purity and completeness decrease, although they remain much higher than we initially expected. We extended our test cases to mock surveys with an average separation of 15 h-1 Mpc, meant to reproduce high source density areas of the Baryon Oscillation Spectroscopic Survey. We find that even with such a large sightline separation, the method can still be used to find some of the largest protoclusters.

  20. 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.

  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. 21 CFR 892.1740 - Tomographic x-ray system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Tomographic x-ray system. 892.1740 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1740 Tomographic x-ray system. (a) Identification. A tomographic x-ray system is an x-ray device intended to be used to produce radiologic images...

  4. 21 CFR 892.1740 - Tomographic x-ray system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tomographic x-ray system. 892.1740 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1740 Tomographic x-ray system. (a) Identification. A tomographic x-ray system is an x-ray device intended to be used to produce radiologic images...

  5. 21 CFR 892.1740 - Tomographic x-ray system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Tomographic x-ray system. 892.1740 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1740 Tomographic x-ray system. (a) Identification. A tomographic x-ray system is an x-ray device intended to be used to produce radiologic images...

  6. 21 CFR 892.1740 - Tomographic x-ray system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Tomographic x-ray system. 892.1740 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1740 Tomographic x-ray system. (a) Identification. A tomographic x-ray system is an x-ray device intended to be used to produce radiologic images...

  7. 21 CFR 892.1740 - Tomographic x-ray system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Tomographic x-ray system. 892.1740 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1740 Tomographic x-ray system. (a) Identification. A tomographic x-ray system is an x-ray device intended to be used to produce radiologic images...

  8. 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.

  9. 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.

  10. Scalable Computer Performance and Analysis (Hierarchical INTegration)

    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.

  11. Bone augmentation of the atrophic anterior maxilla for dental implants using rhBMP-2 and titanium mesh: histological and tomographic analysis.

    PubMed

    Ribeiro Filho, S A; Francischone, C E; de Oliveira, J C; Ribeiro, L Z; do Prado, F Z X; Sotto-Maior, B S

    2015-12-01

    The loss of multiple teeth or trauma to the anterior maxilla often results in a deficient ridge width for prosthetic tooth rehabilitation. This study evaluated the use of titanium mesh and recombinant human bone morphogenetic protein 2 (rhBMP-2) for the repair of major bone defects in the alveolar bone. Five patients were enrolled in the study; these patients required implant replacements for two contiguous missing teeth in the anterior maxilla, which lacked sufficient bone. Residual ridges were augmented with rhBMP-2 and titanium mesh to direct the geometry of the newly formed bone. Seven months later, a bone biopsy specimen was removed from the implantation site before osteotomy and insertion of dental implants. Cone beam computed tomography (CBCT) scans were obtained preoperatively, postoperatively (baseline), and 48 months after implantation to evaluate implant healing. All dental implants were placed in the grafted sites without the need for further bone augmentation. The most frequent adverse effects were facial oedema and oral erythema. Biopsy specimens were used to evaluate bone quality. CBCT scans provided a prediction of alveolar restoration and long-term success. The combination of rhBMP-2 and titanium mesh provided effective augmentation of the atrophic anterior maxilla prior to implant placement.

  12. Computed Tomographic Imaging of Subchondral Fatigue Cracks in the Distal End of the Third Metacarpal Bone in the Thoroughbred Racehorse Can Predict Crack Micromotion in an Ex-Vivo Model

    PubMed Central

    Dubois, Marie-Soleil; Morello, Samantha; Rayment, Kelsey; Markel, Mark D.; Vanderby, Ray; Kalscheur, Vicki L.; Hao, Zhengling; McCabe, Ronald P.; Marquis, Patricia; Muir, Peter

    2014-01-01

    Articular stress fracture arising from the distal end of the third metacarpal bone (MC3) is a common serious injury in Thoroughbred racehorses. Currently, there is no method for predicting fracture risk clinically. We describe an ex-vivo biomechanical model in which we measured subchondral crack micromotion under compressive loading that modeled high speed running. Using this model, we determined the relationship between subchondral crack dimensions measured using computed tomography (CT) and crack micromotion. Thoracic limbs from 40 Thoroughbred racehorses that had sustained a catastrophic injury were studied. Limbs were radiographed and examined using CT. Parasagittal subchondral fatigue crack dimensions were measured on CT images using image analysis software. MC3 bones with fatigue cracks were tested using five cycles of compressive loading at -7,500N (38 condyles, 18 horses). Crack motion was recorded using an extensometer. Mechanical testing was validated using bones with 3 mm and 5 mm deep parasagittal subchondral slots that modeled naturally occurring fatigue cracks. After testing, subchondral crack density was determined histologically. Creation of parasagittal subchondral slots induced significant micromotion during loading (p<0.001). In our biomechanical model, we found a significant positive correlation between extensometer micromotion and parasagittal crack area derived from reconstructed CT images (SR = 0.32, p<0.05). Correlations with transverse and frontal plane crack lengths were not significant. Histologic fatigue damage was not significantly correlated with crack dimensions determined by CT or extensometer micromotion. Bones with parasagittal crack area measurements above 30 mm2 may have a high risk of crack propagation and condylar fracture in vivo because of crack micromotion. In conclusion, our results suggest that CT could be used to quantify subchondral fatigue crack dimensions in racing Thoroughbred horses in-vivo to assess risk of

  13. A comparative evaluation of the increase in root canal surface area and canal transportation in curved root canals by three rotary systems: A cone-beam computed tomographic study

    PubMed Central

    Prasanthi, Nalam NVD; Rambabu, Tanikonda; Sajjan, Girija S; Varma, K Madhu; Satish, R Kalyan; Padmaja, M

    2016-01-01

    Aim: The aim of this study was to measure the increase in root canal surface area and canal transportation after biomechanical preparation at 1, 3, and 5 mm short of the apex with three different rotary systems in both continuous rotary and reciprocating rotary motions. Materials and Methods: Sixty freshly extracted human mandibular molars with mesial root canal curvatures between 20° and 30° were included in the study. Teeth were randomly distributed into three groups (n = 20). Biomechanical preparations were done in all the mesial canals. In Group 1, instrumentation was done with ProTaper universal rotary files, Group 2, with K3XF rotary files, and Group 3, with LSX rotary files. Each group was further subdivided into subgroups A and B (n = 10) where instrumentation was done by continuous rotary and reciprocating rotary techniques, respectively. Increase in root canal surface area and canal transportation was measured using the preoperative and postoperative cone-beam computed tomography scans. Statistical Analysis: The data were analyzed by one-way ANOVA followed by Tukey pairwise multiple comparison tests. Results: Increase in root canal surface area was significantly more (P < 0.05) in ProTaper and K3XF groups when compared to LSX group. Canal transportation was significantly more (P < 0.05) in ProTaper group when compared to K3XF and LSX groups. There was no significant difference (P > 0.05) in increase of root canal surface area and canal transportation between continuous rotary and reciprocating rotary techniques for ProTaper Universal, K3XF and LSX groups. Conclusion: LSX rotary system showed minimal increase of root canal surface area and minimal canal transportation when compared to ProTaper and K3XF rotary systems.

  14. A comparative evaluation of the increase in root canal surface area and canal transportation in curved root canals by three rotary systems: A cone-beam computed tomographic study

    PubMed Central

    Prasanthi, Nalam NVD; Rambabu, Tanikonda; Sajjan, Girija S; Varma, K Madhu; Satish, R Kalyan; Padmaja, M

    2016-01-01

    Aim: The aim of this study was to measure the increase in root canal surface area and canal transportation after biomechanical preparation at 1, 3, and 5 mm short of the apex with three different rotary systems in both continuous rotary and reciprocating rotary motions. Materials and Methods: Sixty freshly extracted human mandibular molars with mesial root canal curvatures between 20° and 30° were included in the study. Teeth were randomly distributed into three groups (n = 20). Biomechanical preparations were done in all the mesial canals. In Group 1, instrumentation was done with ProTaper universal rotary files, Group 2, with K3XF rotary files, and Group 3, with LSX rotary files. Each group was further subdivided into subgroups A and B (n = 10) where instrumentation was done by continuous rotary and reciprocating rotary techniques, respectively. Increase in root canal surface area and canal transportation was measured using the preoperative and postoperative cone-beam computed tomography scans. Statistical Analysis: The data were analyzed by one-way ANOVA followed by Tukey pairwise multiple comparison tests. Results: Increase in root canal surface area was significantly more (P < 0.05) in ProTaper and K3XF groups when compared to LSX group. Canal transportation was significantly more (P < 0.05) in ProTaper group when compared to K3XF and LSX groups. There was no significant difference (P > 0.05) in increase of root canal surface area and canal transportation between continuous rotary and reciprocating rotary techniques for ProTaper Universal, K3XF and LSX groups. Conclusion: LSX rotary system showed minimal increase of root canal surface area and minimal canal transportation when compared to ProTaper and K3XF rotary systems. PMID:27656062

  15. 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.

  16. Fluorescence and diffusive wave diffraction tomographic probes in turbid media

    NASA Astrophysics Data System (ADS)

    Li, Xingde

    1998-10-01

    Light transport over long distances in tissue-like highly scattering media is well approximated as a diffusive process. Diffusing photons can be used to detect, localize and characterize non-invasively optical inhomogeneities such as tumors and hematomas embedded in thick biological tissue. Most of the contrast relies on the endogenous optical property differences between the inhomogeneities and the surrounding media. Recently exogenous fluorescent contrast agents have been considered as a means to enhance the sensitivity and specificity for tumor detection. In the first part of the thesis (Chapter 2 and 3), a theoretical basis is established for modeling the transport, of fluorescent photons in highly scattering media. Fluorescent Diffuse Photon Density Waves (FDPDW) are used to describe the transport of fluorescent photons. A detailed analysis based upon a practical signal-to-noise model was used to access the utility of the fluorescent method. The analysis reveals that a small heterogeneity, embedded in deep tissue-like turbid media with biologically relevant parameters, and with a practically achievable 5-fold fluorophore concentration contrast, can be detected and localized when its radius is greater than 0.2 cm, and can be characterized when its radius is greater than 0.7 cm. In vivo and preliminary clinical studies demonstrate the feasibility of using FDPDW's for tumor diagnosis. Optical imaging with diffusing photons is challenging. Many of the imaging algorithms developed so far are either fundamentally incorrect as in the case of back- projection approach, or require a huge amount of computational resources and CPU time. In the second part of the thesis (Chapter 4), a fast, K-space diffraction tomographic imaging algorithm based upon spatial angular spectrum analysis is derived and applied. Absolute optical properties of thin inhomogeneities and relative optical properties of spatially extended inhomogeneities are reconstructed within a sub-second time

  17. Effect of exercise level on the ability of thallium-201 tomographic imaging in detecting coronary artery disease: Analysis of 461 patients

    SciTech Connect

    Iskandrian, A.S.; Heo, J.; Kong, B.; Lyons, E. )

    1989-11-15

    This study examined the effect of the level of exercise on the ability of thallium-201 imaging with single photon emission computed tomography (SPECT) to detect coronary artery disease. Patients in group 1 (n = 164) achieved adequate exercise end points, defined as positive exercise electrocardiograms or greater than or equal to 85% of maximal predicted heart rate. Patients in group 2 (n = 108) had submaximal exercise. The SPECT thallium-201 images showed perfusion defects in 74%, 88%, and 98%, respectively, of patients with one, two and three vessel coronary artery disease in group 1, compared with 52%, 84% and 79%, respectively, of such patients in group 2 (p less than 0.05). Perfusion defects showed partial or complete redistribution consistent with ischemia in 56%, 80% and 88%, respectively, of patients with one, two and three vessel coronary artery disease in group 1 compared with 35%, 58% and 56%, respectively, of such patients in group 2 (p = 0.08, less than 0.03 and less than 0.001, respectively). Of 58 patients with normal coronary angiograms or less than 50% diameter stenosis, 36 (62%) had normal SPECT images. In a separate group of 131 patients with less than 5% pretest probability of coronary artery disease, the specificity was 93%. The sensitivity of exercise SPECT imaging in group 1 was higher than that of ST segment depression (p less than 0.001). Thus, the level of exercise affects the results of SPECT thallium imaging in the localization and evaluation of the extent of coronary artery disease and the detection of ischemia.

  18. Tomographic Gamma Scanner Experience: Three Cases

    SciTech Connect

    Mercer, David J.

    2014-06-30

    This is a summary of field applications of tomographic gamma scanning (TGS). Three cases are shown: enriched uranium scanning at Rocky Flats, heat-source plutonium at LANL, and plutonium-bearing pyrochemical salts at Rocky Flats. Materials are taken from the references shown below.

  19. 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.

  20. 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…

  1. 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.

  2. 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.

  3. 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.

  4. 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…

  5. 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…

  6. 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.

  7. Computational Modeling, Formal Analysis, and Tools for Systems Biology

    PubMed Central

    Bartocci, Ezio; Lió, Pietro

    2016-01-01

    As the amount of biological data in the public domain grows, so does the range of modeling and analysis techniques employed in systems biology. In recent years, a number of theoretical computer science developments have enabled modeling methodology to keep pace. The growing interest in systems biology in executable models and their analysis has necessitated the borrowing of terms and methods from computer science, such as formal analysis, model checking, static analysis, and runtime verification. Here, we discuss the most important and exciting computational methods and tools currently available to systems biologists. We believe that a deeper understanding of the concepts and theory highlighted in this review will produce better software practice, improved investigation of complex biological processes, and even new ideas and better feedback into computer science. PMID:26795950

  8. Computational Modeling, Formal Analysis, and Tools for Systems Biology.

    PubMed

    Bartocci, Ezio; Lió, Pietro

    2016-01-01

    As the amount of biological data in the public domain grows, so does the range of modeling and analysis techniques employed in systems biology. In recent years, a number of theoretical computer science developments have enabled modeling methodology to keep pace. The growing interest in systems biology in executable models and their analysis has necessitated the borrowing of terms and methods from computer science, such as formal analysis, model checking, static analysis, and runtime verification. Here, we discuss the most important and exciting computational methods and tools currently available to systems biologists. We believe that a deeper understanding of the concepts and theory highlighted in this review will produce better software practice, improved investigation of complex biological processes, and even new ideas and better feedback into computer science.

  9. Surveillance Analysis Computer System (SACS) software requirements specification (SRS)

    SciTech Connect

    Glasscock, J.A.; Flanagan, M.J.

    1995-09-01

    This document is the primary document establishing requirements for the Surveillance Analysis Computer System (SACS) Database, an Impact Level 3Q system. The purpose is to provide the customer and the performing organization with the requirements for the SACS Project.

  10. Computer analysis of digital well logs

    USGS Publications Warehouse

    Scott, James H.

    1984-01-01

    A comprehensive system of computer programs has been developed by the U.S. Geological Survey for analyzing digital well logs. The programs are operational on a minicomputer in a research well-logging truck, making it possible to analyze and replot the logs while at the field site. The minicomputer also serves as a controller of digitizers, counters, and recorders during acquisition of well logs. The analytical programs are coordinated with the data acquisition programs in a flexible system that allows the operator to make changes quickly and easily in program variables such as calibration coefficients, measurement units, and plotting scales. The programs are designed to analyze the following well-logging measurements: natural gamma-ray, neutron-neutron, dual-detector density with caliper, magnetic susceptibility, single-point resistance, self potential, resistivity (normal and Wenner configurations), induced polarization, temperature, sonic delta-t, and sonic amplitude. The computer programs are designed to make basic corrections for depth displacements, tool response characteristics, hole diameter, and borehole fluid effects (when applicable). Corrected well-log measurements are output to magnetic tape or plotter with measurement units transformed to petrophysical and chemical units of interest, such as grade of uranium mineralization in percent eU3O8, neutron porosity index in percent, and sonic velocity in kilometers per second.

  11. Initial results from the Donner 600 crystal positron tomograph

    SciTech Connect

    Derenzo, S.E.; Huesman, R.H.; Cahoon, J.L.; Geyer, A.; Uber, D.; Vuletich, T.; Budinger, T.F.

    1986-10-01

    We describe a positron tomograph using a single ring of 600 close-packed 3 mm wide bismuth germanate (BGO) crystals coupled to 14 mm phototubes. The phototube preamplifier circuit derives a timing pulse from the first photoelectron, and sends it to address and coincidence circuits only if the integrated pulse height is within a pre-set window. The timing delays and pulse height windows for all 600 detectors and the coincidence timing windows are computer adjustable. An orbiting positron source is used for transmission measurements and a look-up table is used to reject scattered and random coincidences that do not pass through the source. Data can be acquired using a stationary mode for 1.57 mm lateral sampling or the two-position clam sampling mode for 0.79 mm lateral sampling. High maximum data rates are provided by 45 parallel coincidence circuits and 4 parallel histogram memory units. With two-position sampling and 1.57 mm bins, the reconstructed point spread function (PSF) of a 0.35 mm diam /sup 22/Na wire source at the center of the tomograph is circular with 2.9 mm full-width at half-maximum (fwhm) and the PSF at a distance of 8 cm from the center is elliptical with a radial fwhm of 4.0 mm and tangential fwhm of 3.0 mm. 12 refs., 6 figs., 3 tabs.

  12. Analysis and computer tools for separation processes involving nonideal mixtures

    SciTech Connect

    Lucia, A.

    1992-05-01

    The objectives of this research, were to continue to further both the theoretical understanding of and the development of computer tools (algorithms) for separation processes involving nonideal mixtures. These objectives were divided into three interrelated major areas -- the mathematical analysis of the number of steady-state solutions to multistage separation processes, the numerical analysis of general, related fixed-point methods, and the development and implementation of computer tools for process simulation.

  13. Process for computing geometric perturbations for probabilistic analysis

    DOEpatents

    Fitch, Simeon H. K.; Riha, David S.; Thacker, Ben H.

    2012-04-10

    A method for computing geometric perturbations for probabilistic analysis. The probabilistic analysis is based on finite element modeling, in which uncertainties in the modeled system are represented by changes in the nominal geometry of the model, referred to as "perturbations". These changes are accomplished using displacement vectors, which are computed for each node of a region of interest and are based on mean-value coordinate calculations.

  14. System Matrix Analysis for Computed Tomography Imaging

    PubMed Central

    Flores, Liubov; Vidal, Vicent; Verdú, Gumersindo

    2015-01-01

    In practical applications of computed tomography imaging (CT), it is often the case that the set of projection data is incomplete owing to the physical conditions of the data acquisition process. On the other hand, the high radiation dose imposed on patients is also undesired. These issues demand that high quality CT images can be reconstructed from limited projection data. For this reason, iterative methods of image reconstruction have become a topic of increased research interest. Several algorithms have been proposed for few-view CT. We consider that the accurate solution of the reconstruction problem also depends on the system matrix that simulates the scanning process. In this work, we analyze the application of the Siddon method to generate elements of the matrix and we present results based on real projection data. PMID:26575482

  15. RSAC -6 Radiological Safety Analysis Computer Program

    SciTech Connect

    Schrader, Bradley J; Wenzel, Douglas Rudolph

    2001-06-01

    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 and 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 FGR 11 and 12.

  16. Computational analysis of small RNA cloning data.

    PubMed

    Berninger, Philipp; Gaidatzis, Dimos; van Nimwegen, Erik; Zavolan, Mihaela

    2008-01-01

    Cloning and sequencing is the method of choice for small regulatory RNA identification. Using deep sequencing technologies one can now obtain up to a billion nucleotides--and tens of millions of small RNAs--from a single library. Careful computational analyses of such libraries enabled the discovery of miRNAs, rasiRNAs, piRNAs, and 21U RNAs. Given the large number of sequences that can be obtained from each individual sample, deep sequencing may soon become an alternative to oligonucleotide microarray technology for mRNA expression profiling. In this report we present the methods that we developed for the annotation and expression profiling of small RNAs obtained through large-scale sequencing. These include a fast algorithm for finding nearly perfect matches of small RNAs in sequence databases, a web-accessible software system for the annotation of small RNA libraries, and a Bayesian method for comparing small RNA expression across samples.

  17. System Matrix Analysis for Computed Tomography Imaging.

    PubMed

    Flores, Liubov; Vidal, Vicent; Verdú, Gumersindo

    2015-01-01

    In practical applications of computed tomography imaging (CT), it is often the case that the set of projection data is incomplete owing to the physical conditions of the data acquisition process. On the other hand, the high radiation dose imposed on patients is also undesired. These issues demand that high quality CT images can be reconstructed from limited projection data. For this reason, iterative methods of image reconstruction have become a topic of increased research interest. Several algorithms have been proposed for few-view CT. We consider that the accurate solution of the reconstruction problem also depends on the system matrix that simulates the scanning process. In this work, we analyze the application of the Siddon method to generate elements of the matrix and we present results based on real projection data. PMID:26575482

  18. Dense velocity reconstruction from tomographic PTV with material derivatives

    NASA Astrophysics Data System (ADS)

    Schneiders, Jan F. G.; Scarano, Fulvio

    2016-09-01

    A method is proposed to reconstruct the instantaneous velocity field from time-resolved volumetric particle tracking velocimetry (PTV, e.g., 3D-PTV, tomographic PTV and Shake-the-Box), employing both the instantaneous velocity and the velocity material derivative of the sparse tracer particles. The constraint to the measured temporal derivative of the PTV particle tracks improves the consistency of the reconstructed velocity field. The method is christened as pouring time into space, as it leverages temporal information to increase the spatial resolution of volumetric PTV measurements. This approach becomes relevant in cases where the spatial resolution is limited by the seeding concentration. The method solves an optimization problem to find the vorticity and velocity fields that minimize a cost function, which includes next to instantaneous velocity, also the velocity material derivative. The velocity and its material derivative are related through the vorticity transport equation, and the cost function is minimized using the limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) algorithm. The procedure is assessed numerically with a simulated PTV experiment in a turbulent boundary layer from a direct numerical simulation (DNS). The experimental validation considers a tomographic particle image velocimetry (PIV) experiment in a similar turbulent boundary layer and the additional case of a jet flow. The proposed technique (`vortex-in-cell plus', VIC+) is compared to tomographic PIV analysis (3D iterative cross-correlation), PTV interpolation methods (linear and adaptive Gaussian windowing) and to vortex-in-cell (VIC) interpolation without the material derivative. A visible increase in resolved details in the turbulent structures is obtained with the VIC+ approach, both in numerical simulations and experiments. This results in a more accurate determination of the turbulent stresses distribution in turbulent boundary layer investigations. Data from a jet

  19. CANARY phase B: on-sky open-loop tomographic LGS AO results

    NASA Astrophysics Data System (ADS)

    Morris, Tim; Gendron, Eric; Basden, Alastair; Martin, Olivier; Osborn, James; Henry, David; Hubert, Zoltan; Sivo, Gaetano; Gratadour, Damien; Chemla, Fanny; Sevin, Arnaud; Cohen, Matthieu; Younger, Eddy; Vidal, Fabrice; Wilson, Richard; Butterley, Tim; Bitenc, Urban; Reeves, Andrew; Bharmal, Nazim; Raynaud, Henri-François; Kulcsar, Caroline; Conan, Jean-Marc; Huet, Jean-Michel; Perret, Denis; Dickson, Colin; Atkinson, David; Bailie, Tom; Longmore, Andy; Todd, Stephen; Talbot, Gordon; Morris, Simon; Rousset, Gérard; Myers, Richard

    2014-07-01

    CANARY is an on-sky Laser Guide Star (LGS) tomographic AO demonstrator that has been in operation at the 4.2m William Herschel Telescope (WHT) in La Palma since 2010. In 2013, CANARY was upgraded from its initial configuration that used three off-axis Natural Guide Stars (NGS) through the inclusion of four off-axis Rayleigh LGS and associated wavefront sensing system. Here we present the system and analysis of the on-sky results obtained at the WHT between May and September 2014. Finally we present results from the final `Phase C' CANARY system that aims to recreate the tomographic configuration to emulate the expected tomographic AO configuration of both the AOF at the VLT and E-ELT.

  20. Computer-automated neutron activation analysis system

    SciTech Connect

    Minor, M.M.; Garcia, S.R.

    1983-01-01

    An automated delayed neutron counting and instrumental neutron activation analysis system has been developed at Los Alamos National Laboratory's Omega West Reactor (OWR) to analyze samples for uranium and 31 additional elements with a maximum throughput of 400 samples per day. 5 references.

  1. Solving large tomographic linear systems: size reduction and error estimation

    NASA Astrophysics Data System (ADS)

    Voronin, Sergey; Mikesell, Dylan; Slezak, Inna; Nolet, Guust

    2014-10-01

    We present a new approach to reduce a sparse, linear system of equations associated with tomographic inverse problems. We begin by making a modification to the commonly used compressed sparse-row format, whereby our format is tailored to the sparse structure of finite-frequency (volume) sensitivity kernels in seismic tomography. Next, we cluster the sparse matrix rows to divide a large matrix into smaller subsets representing ray paths that are geographically close. Singular value decomposition of each subset allows us to project the data onto a subspace associated with the largest eigenvalues of the subset. After projection we reject those data that have a signal-to-noise ratio (SNR) below a chosen threshold. Clustering in this way assures that the sparse nature of the system is minimally affected by the projection. Moreover, our approach allows for a precise estimation of the noise affecting the data while also giving us the ability to identify outliers. We illustrate the method by reducing large matrices computed for global tomographic systems with cross-correlation body wave delays, as well as with surface wave phase velocity anomalies. For a massive matrix computed for 3.7 million Rayleigh wave phase velocity measurements, imposing a threshold of 1 for the SNR, we condensed the matrix size from 1103 to 63 Gbyte. For a global data set of multiple-frequency P wave delays from 60 well-distributed deep earthquakes we obtain a reduction to 5.9 per cent. This type of reduction allows one to avoid loss of information due to underparametrizing models. Alternatively, if data have to be rejected to fit the system into computer memory, it assures that the most important data are preserved.

  2. Computational mechanics analysis tools for parallel-vector supercomputers

    NASA Technical Reports Server (NTRS)

    Storaasli, Olaf O.; Nguyen, Duc T.; Baddourah, Majdi; Qin, Jiangning

    1993-01-01

    Computational algorithms for structural analysis on parallel-vector supercomputers are reviewed. These parallel algorithms, developed by the authors, are for the assembly of structural equations, 'out-of-core' strategies for linear equation solution, massively distributed-memory equation solution, unsymmetric equation solution, general eigensolution, geometrically nonlinear finite element analysis, design sensitivity analysis for structural dynamics, optimization search analysis and domain decomposition. The source code for many of these algorithms is available.

  3. Local spatial frequency analysis for computer vision

    NASA Technical Reports Server (NTRS)

    Krumm, John; Shafer, Steven A.

    1990-01-01

    A sense of vision is a prerequisite for a robot to function in an unstructured environment. However, real-world scenes contain many interacting phenomena that lead to complex images which are difficult to interpret automatically. Typical computer vision research proceeds by analyzing various effects in isolation (e.g., shading, texture, stereo, defocus), usually on images devoid of realistic complicating factors. This leads to specialized algorithms which fail on real-world images. Part of this failure is due to the dichotomy of useful representations for these phenomena. Some effects are best described in the spatial domain, while others are more naturally expressed in frequency. In order to resolve this dichotomy, we present the combined space/frequency representation which, for each point in an image, shows the spatial frequencies at that point. Within this common representation, we develop a set of simple, natural theories describing phenomena such as texture, shape, aliasing and lens parameters. We show these theories lead to algorithms for shape from texture and for dealiasing image data. The space/frequency representation should be a key aid in untangling the complex interaction of phenomena in images, allowing automatic understanding of real-world scenes.

  4. Acoustic analysis of a computer cooling fan

    NASA Astrophysics Data System (ADS)

    Huang, Lixi; Wang, Jian

    2005-10-01

    Noise radiated by a typical computer cooling fan is investigated experimentally and analyzed within the framework of rotor-stator interaction noise using point source formulation. The fan is 9 cm in rotor casing diameter and its design speed is 3000 rpm. The main noise sources are found and quantified; they are (a) the inlet flow distortion caused by the sharp edges of the incomplete bellmouth due to the square outer framework, (b) the interaction of rotor blades with the downstream struts which hold the motor, and (c) the extra size of one strut carrying electrical wiring. Methods are devised to extract the rotor-strut interaction noise, (b) and (c), radiated by the component forces of drag and thrust at the leading and higher order spinning pressure modes, as well as the leading edge noise generated by (a). By re-installing the original fan rotor in various casings, the noises radiated by the three features of the original fan are separated, and details of the directivity are interpreted. It is found that the inlet flow distortion and the unequal set of four struts make about the same amount of noise. Their corrections show a potential of around 10-dB sound power reduction.

  5. Adaptive computational methods for aerothermal heating analysis

    NASA Technical Reports Server (NTRS)

    Price, John M.; Oden, J. Tinsley

    1988-01-01

    The development of adaptive gridding techniques for finite-element analysis of fluid dynamics equations is described. The developmental work was done with the Euler equations with concentration on shock and inviscid flow field capturing. Ultimately this methodology is to be applied to a viscous analysis for the purpose of predicting accurate aerothermal loads on complex shapes subjected to high speed flow environments. The development of local error estimate strategies as a basis for refinement strategies is discussed, as well as the refinement strategies themselves. The application of the strategies to triangular elements and a finite-element flux-corrected-transport numerical scheme are presented. The implementation of these strategies in the GIM/PAGE code for 2-D and 3-D applications is documented and demonstrated.

  6. Interactive Spectral Analysis and Computation (ISAAC)

    NASA Technical Reports Server (NTRS)

    Lytle, D. M.

    1992-01-01

    Isaac is a task in the NSO external package for IRAF. A descendant of a FORTRAN program written to analyze data from a Fourier transform spectrometer, the current implementation has been generalized sufficiently to make it useful for general spectral analysis and other one dimensional data analysis tasks. The user interface for Isaac is implemented as an interpreted mini-language containing a powerful, programmable vector calculator. Built-in commands provide much of the functionality needed to produce accurate line lists from input spectra. These built-in functions include automated spectral line finding, least squares fitting of Voigt profiles to spectral lines including equality constraints, various filters including an optimal filter construction tool, continuum fitting, and various I/O functions.

  7. Bayesian tomographic reconstruction of microsystems

    NASA Astrophysics Data System (ADS)

    Salem, Sofia Fekih; Vabre, Alexandre; Mohammad-Djafari, Ali

    2007-11-01

    The microtomography by X ray transmission plays an increasingly dominating role in the study and the understanding of microsystems. Within this framework, an experimental setup of high resolution X ray microtomography was developed at CEA-List to quantify the physical parameters related to the fluids flow in microsystems. Several difficulties rise from the nature of experimental data collected on this setup: enhanced error measurements due to various physical phenomena occurring during the image formation (diffusion, beam hardening), and specificities of the setup (limited angle, partial view of the object, weak contrast). To reconstruct the object we must solve an inverse problem. This inverse problem is known to be ill-posed. It therefore needs to be regularized by introducing prior information. The main prior information we account for is that the object is composed of a finite known number of different materials distributed in compact regions. This a priori information is introduced via a Gauss-Markov field for the contrast distributions with a hidden Potts-Markov field for the class materials in the Bayesian estimation framework. The computations are done by using an appropriate Markov Chain Monte Carlo (MCMC) technique. In this paper, we present first the basic steps of the proposed algorithms. Then we focus on one of the main steps in any iterative reconstruction method which is the computation of forward and adjoint operators (projection and backprojection). A fast implementation of these two operators is crucial for the real application of the method. We give some details on the fast computation of these steps and show some preliminary results of simulations.

  8. AIR INGRESS ANALYSIS: COMPUTATIONAL FLUID DYNAMIC MODELS

    SciTech Connect

    Chang H. Oh; Eung S. Kim; Richard Schultz; Hans Gougar; David Petti; Hyung S. Kang

    2010-08-01

    The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high temperature reactors (VHTRs). Phenomena Identification and Ranking Studies to date have ranked an air ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the High Temperature Gas Cooled Reactor through the break, possibly causing oxidation of the in-the core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of the lower plenum graphite can lead to a loss of structural support. Excessive oxidation of core graphite can also lead to the release of fission products into the confinement, which could be detrimental to a reactor safety. Computational fluid dynamic model developed in this study will improve our understanding of this phenomenon. This paper presents two-dimensional and three-dimensional CFD results for the quantitative assessment of the air ingress phenomena. A portion of results of the density-driven stratified flow in the inlet pipe will be compared with results of the experimental results.

  9. COMPUTATIONAL FLUID DYNAMICS MODELING ANALYSIS OF COMBUSTORS

    SciTech Connect

    Mathur, M.P.; Freeman, Mark; Gera, Dinesh

    2001-11-06

    In the current fiscal year FY01, several CFD simulations were conducted to investigate the effects of moisture in biomass/coal, particle injection locations, and flow parameters on carbon burnout and NO{sub x} inside a 150 MW GEEZER industrial boiler. Various simulations were designed to predict the suitability of biomass cofiring in coal combustors, and to explore the possibility of using biomass as a reburning fuel to reduce NO{sub x}. Some additional CFD simulations were also conducted on CERF combustor to examine the combustion characteristics of pulverized coal in enriched O{sub 2}/CO{sub 2} environments. Most of the CFD models available in the literature treat particles to be point masses with uniform temperature inside the particles. This isothermal condition may not be suitable for larger biomass particles. To this end, a stand alone program was developed from the first principles to account for heat conduction from the surface of the particle to its center. It is envisaged that the recently developed non-isothermal stand alone module will be integrated with the Fluent solver during next fiscal year to accurately predict the carbon burnout from larger biomass particles. Anisotropy in heat transfer in radial and axial will be explored using different conductivities in radial and axial directions. The above models will be validated/tested on various fullscale industrial boilers. The current NO{sub x} modules will be modified to account for local CH, CH{sub 2}, and CH{sub 3} radicals chemistry, currently it is based on global chemistry. It may also be worth exploring the effect of enriched O{sub 2}/CO{sub 2} environment on carbon burnout and NO{sub x} concentration. The research objective of this study is to develop a 3-Dimensional Combustor Model for Biomass Co-firing and reburning applications using the Fluent Computational Fluid Dynamics Code.

  10. Computer-Aided Communication Satellite System Analysis and Optimization.

    ERIC Educational Resources Information Center

    Stagl, Thomas W.; And Others

    Various published computer programs for fixed/broadcast communication satellite system synthesis and optimization are discussed. The rationale for selecting General Dynamics/Convair's Satellite Telecommunication Analysis and Modeling Program (STAMP) in modified form to aid in the system costing and sensitivity analysis work in the Program on…

  11. Computational fluid dynamic analysis of liquid rocket combustion instability

    NASA Technical Reports Server (NTRS)

    Venkateswaran, Sankaran; Grenda, Jeffrey; Merkle, Charles L.

    1991-01-01

    The paper presents a computational analysis of liquid rocket combustion instability. Consideration is given to both a fully nonlinear unsteady calculation as well as a new CFD-based linearized stability analysis. An analytical solution for the linear stability problem in a constant area combustion chamber with uniform mean flow is developed to verify the numerical analyses.

  12. A Computer Program to Determine Reliability Using Analysis of Variance

    ERIC Educational Resources Information Center

    Burns, Edward

    1976-01-01

    A computer program, written in Fortran IV, is described which assesses reliability by using analysis of variance. It produces a complete analysis of variance table in addition to reliability coefficients for unadjusted and adjusted data as well as the intraclass correlation for m subjects and n items. (Author)

  13. Two Computer Programs for Factor Analysis. Technical Note Number 41.

    ERIC Educational Resources Information Center

    Wisler, Carl E.

    Two factor analysis algorithms, previously described by P. Horst, have been programed for use on the General Electric Time-Sharing Computer System. The first of these, Principal Components Analysis (PCA), uses the Basic Structure Successive Factor Method With Residual Matrices algorithm to obtain the principal component vectors of a correlation…

  14. Computing environments for data analysis III: Programming environments

    SciTech Connect

    McDonald, J.A.; Pedersen, J.

    1988-03-01

    This is the third in a series of papers on aspects of modern computing environments that are relevant to statistical data analysis. In this paper the authors discuss programming environments. In particular, they argue that integrated programming environments (for example, Lisp and Smalltalk environments) are more appropriate as a base for data analysis than conventional operating systems (for example, Unix).

  15. Computational Aeroelastic Analysis of the Ares Launch Vehicle During Ascent

    NASA Technical Reports Server (NTRS)

    Bartels, Robert E.; Chwalowski, Pawel; Massey, Steven J.; Vatsa, Veer N.; Heeg, Jennifer; Wieseman, Carol D.; Mineck, Raymond E.

    2010-01-01

    This paper presents the static and dynamic computational aeroelastic (CAE) analyses of the Ares crew launch vehicle (CLV) during atmospheric ascent. The influence of launch vehicle flexibility on the static aerodynamic loading and integrated aerodynamic force and moment coefficients is discussed. The ultimate purpose of this analysis is to assess the aeroelastic stability of the launch vehicle along the ascent trajectory. A comparison of analysis results for several versions of the Ares CLV will be made. Flexible static and dynamic analyses based on rigid computational fluid dynamic (CFD) data are compared with a fully coupled aeroelastic time marching CFD analysis of the launch vehicle.

  16. AVES: A Computer Cluster System approach for INTEGRAL Scientific Analysis

    NASA Astrophysics Data System (ADS)

    Federici, M.; Martino, B. L.; Natalucci, L.; Umbertini, P.

    The AVES computing system, based on an "Cluster" architecture is a fully integrated, low cost computing facility dedicated to the archiving and analysis of the INTEGRAL data. AVES is a modular system that uses the software resource manager (SLURM) and allows almost unlimited expandibility (65,536 nodes and hundreds of thousands of processors); actually is composed by 30 Personal Computers with Quad-Cores CPU able to reach the computing power of 300 Giga Flops (300x10{9} Floating point Operations Per Second), with 120 GB of RAM and 7.5 Tera Bytes (TB) of storage memory in UFS configuration plus 6 TB for users area. AVES was designed and built to solve growing problems raised from the analysis of the large data amount accumulated by the INTEGRAL mission (actually about 9 TB) and due to increase every year. The used analysis software is the OSA package, distributed by the ISDC in Geneva. This is a very complex package consisting of dozens of programs that can not be converted to parallel computing. To overcome this limitation we developed a series of programs to distribute the workload analysis on the various nodes making AVES automatically divide the analysis in N jobs sent to N cores. This solution thus produces a result similar to that obtained by the parallel computing configuration. In support of this we have developed tools that allow a flexible use of the scientific software and quality control of on-line data storing. The AVES software package is constituted by about 50 specific programs. Thus the whole computing time, compared to that provided by a Personal Computer with single processor, has been enhanced up to a factor 70.

  17. Tomographic Errors From Wavefront Healing

    NASA Astrophysics Data System (ADS)

    Malcolm, A. E.; Trampert, J.

    2008-12-01

    Despite recent advances in full-waveform modeling ray theory is still, for good reasons, the preferred method in global tomography. It is well known that ray theory is most accurate for anomalies that are large compared to the wavelength. Exactly what errors result from the failure of this assumption is less well understood, in spite of the fact that anomalies found in the Earth from ray-based tomography methods are often outside the regime in which ray theory is known to be valid. Using the spectral element method, we have computed exact delay times and compared them to ray-theoretical traveltimes for two classic anomalies, one large and disk-shaped near the core mantle boundary, and the other a plume-like structure extending throughout the mantle. Wavefront healing is apparent in the traveltime anomalies generated by these structures; its effects are strongly asymmetric between P and S arrivals due to wavelength differences and source directionality. Simple computations in two dimensions allow us to develop the intuition necessary to understand how diffractions around the anomalies explain these results. When inverting the exact travel time anomalies with ray theory we expect wavefront healing to have a strong influence on the resulting structures. We anticipate that the asymmetry will be of particular importance in anomalies in the bulk velocity structure.

  18. A feasibility study on gamma-ray tomography by Monte Carlo simulation for development of portable tomographic system.

    PubMed

    Kim, Jongbum; Jung, Sunghee; Moon, Jinho; Cho, Gyuseong

    2012-02-01

    The electron beam X-ray tomographic scanner has been used in industrial and medical field since it was developed two decades ago. However, X-ray electron beam tomography has remained as indoor equipment because of its bulky hardware of X-ray generation devices. By replacing X-ray devices of electron beam CT with a gamma-ray source, a tomographic system can be a portable device. This paper introduces analysis and simulation results on industrial gamma-ray tomographic system with scanning geometry similar to electron beam CT. The gamma-ray tomographic system is introduced through the geometrical layout and analysis on non-uniformly distributed problem. The proposed system adopts clamp-on type device to actualize portable industrial system. MCNPx is used to generate virtual experimental data. Pulse height spectra from F8 tally of MCNPx are obtained for single channel counting data of photo-peak and gross counting. Photo-peak and gross counting data are reconstructed for the cross-sectional image of simulation phantoms by ART, Total Variation algorithm and ML-EM. Image reconstruction results from Monte Carlo simulation show that the proposed tomographic system can provide the image solution for industrial objects. Those results provide the preliminary data for the tomographic scanner, which will be developed in future work. PMID:22079959

  19. Video-rate tomographic phase microscopy.

    PubMed

    Fang-Yen, Christopher; Choi, Wonshik; Sung, Yongjin; Holbrow, Charles J; Dasari, Ramachandra R; Feld, Michael S

    2011-01-01

    Tomographic phase microscopy measures the 3-D refractive index distribution of cells and tissues by combining the information from a series of angle-dependent interferometric phase images. In the original device, the frame rate was limited to 0.1 frames per second (fps) by the technique used to acquire phase images, preventing measurements of moving or rapidly changing samples. We describe an improved tomographic phase microscope in which phase images are acquired via a spatial fringe pattern demodulation method, enabling a full tomogram acquisition rate of 30 fps. In addition, in this system the refractive index is calculated by a diffraction tomography algorithm that accounts for the effects of diffraction in the 3-D reconstruction. We use the instrument to quantitatively monitor rapid changes in refractive index within defined subregions of cells due to exposure to acetic acid or changes in medium osmolarity. PMID:21280892

  20. Synthesis of EM geophysical tomographic data

    SciTech Connect

    Howard, A.Q.; Kretzschmar, J.L.

    1986-02-01

    In order to test tomographic inversion schemes under controlled conditions, we have developed a forward electromagnetic model, using the volume current method (VCM). The algorithm can handle thin irregular-shaped bedding planes as well as inclusions or localized anomalies. It is thus ideal for modeling oil trap regions in the earth. Both transmission and reflection images, in magnitude and phase, are presented. Model results are given for a complex lithology as appropriate for an enhanced oil recovery zone. Particular emphasis is placed upon understanding the qualitative effects of bedding layer planes, both continuous and broken, on the electromagnetic response of an elliptical shaped anomaly. The point is made that resolution of reservoir features in complex lithologies, as encountered in enhanced oil recovery applications, requires accurate processing of both amplitude and phase tomographic data.