WorldWideScience

Sample records for 3d computed tomographic

  1. Measurement of facial soft tissues thickness using 3D computed tomographic images

    Jeong, Ho Gul; Kim, Kee Deog; Shin, Dong Won; Hu, Kyung Seok; Lee, Jae Bum; Park, Hyok; Park, Chang Seo [Yonsei Univ. Hospital, Seoul (Korea, Republic of); Han, Seung Ho [Catholic Univ. of Korea, Seoul (Korea, Republic of)

    2006-03-15

    To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side. The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. There were no statistically significant differences between the direct measurements and those using the 3D images(p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissue thickness more easily in forensic science and anthropology.

  2. Clinical usefulness of facial soft tissues thickness measurement using 3D computed tomographic images

    Jeong, Ho Gul; Kim, Kee Deog; Hu, Kyung Seok; Lee, Jae Bum; Park, Hyok [Maxtron Inc., Seoul (Korea, Republic of); Han, Seung Ho [Catholic Univ. of Korea, Seoul (Korea, Republic of); Choi, Seong Ho; Kim, Chong Kwan; Park, Chang Seo [Yonsei Univ., Seoul (Korea, Republic of)

    2006-06-15

    To evaluate clinical usefulness of facial soft tissue thickness measurement using 3D computed tomographic images. One cadaver that had sound facial soft tissues was chosen for the study. The cadaver was scanned with a Helical CT under following scanning protocols about slice thickness and table speed: 3 mm and 3 mm/sec, 5 mm and 5 mm/sec, 7 mm and 7 mm/sec. The acquired data were reconstructed 1.5, 2.5, 3.5 mm reconstruction interval respectively and the images were transferred to a personal computer. Using a program developed to measure facial soft tissue thickness in 3D image, the facial soft tissue thickness was measured. After the ten-time repeation of the measurement for ten times, repeated measure analysis of variance (ANOVA) was adopted to compare and analyze the measurements using the three scanning protocols. Comparison according to the areas was analysed by Mann-Whitney test. There were no statistically significant intraobserver differences in the measurements of the facial soft tissue thickness using the three scanning protocols (p>0.05). There were no statistically significant differences between measurements in the 3 mm slice thickness and those in the 5 mm, 7 mm slice thickness (p>0.05). There were statistical differences in the 14 of the total 30 measured points in the 5 mm slice thickness and 22 in the 7 mm slice thickness. The facial soft tissue thickness measurement using 3D images of 7 mm slice thickness is acceptable clinically, but those of 5 mm slice thickness is recommended for the more accurate measurement.

  3. Efficacy of 3-D computed tomographic reconstruction in evaluating anatomical relationships of colovesical fistula.

    Shinojima, Toshiaki; Nakajima, Fumio; Koizumi, Jun

    2002-04-01

    A case of colovesical fistula is reported. The anatomy of the pelvis was determined preoperatively with 3-D computed tomography (CT), and the fistula, including adjacent structures, could clearly be seen. Compared with conventional axial CT imaging, 3-D CT provided better and more complete visualization of the anatomical relationships, which facilitated the surgical procedure and provided a good outcome.

  4. 3D Reconstruction Technique for Tomographic PIV

    姜楠; 包全; 杨绍琼

    2015-01-01

    Tomographic particle image velocimetry(Tomo-PIV) is a state-of-the-art experimental technique based on a method of optical tomography to achieve the three-dimensional(3D) reconstruction for three-dimensional three-component(3D-3C) flow velocity measurements. 3D reconstruction for Tomo-PIV is carried out herein. Meanwhile, a 3D simplified tomographic reconstruction model reduced from a 3D volume light inten-sity field with 2D projection images into a 2D Tomo-slice plane with 1D projecting lines, i.e., simplifying this 3D reconstruction into a problem of 2D Tomo-slice plane reconstruction, is applied thereafter. Two kinds of the most well-known algebraic reconstruction techniques, algebraic reconstruction technique(ART) and multiple algebraic reconstruction technique(MART), are compared as well. The principles of the two reconstruction algorithms are discussed in detail, which has been performed by a series of simulation images, yielding the corresponding recon-struction images that show different features between the ART and MART algorithm, and then their advantages and disadvantages are discussed. Further discussions are made for the standard particle image reconstruction when the background noise of the pre-initial particle image has been removed. Results show that the particle image recon-struction has been greatly improved. The MART algorithm is much better than the ART. Furthermore, the computa-tional analyses of two parameters(the particle density and the number of cameras), are performed to study their effects on the reconstruction. Lastly, the 3D volume particle field is reconstructed by using the improved algorithm based on the simplified 3D tomographic reconstruction model, which proves that the algorithm simplification is feasible and it can be applied to the reconstruction of 3D volume particle field in a Tomo-PIV system.

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

    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.

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

    Xu Fang; Mueller, Klaus [Center for Visual Computing, Computer Science Department, Stony Brook University, Stony Brook, NY 11794-4400 (United States)

    2007-07-21

    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{sup -1} for the reconstruction of 512{sup 3} volumes.

  7. 3D printing of preclinical X-ray computed tomographic data sets.

    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.

  8. 3D computed tomographic evaluation of the upper airway space of patients undergoing mandibular distraction osteogenesis for micrognathia.

    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.

  9. Development of an advanced 3D cone beam tomographic system

    Sire, Pascal; Rizo, Philippe; Martin, M.; Grangeat, Pierre; Morisseau, P.

    Due to its high spatial resolution, the 3D X-ray cone-beam tomograph (CT) maximizes understanding of test object microstructure. In order for the present X-ray CT NDT system to control ceramics and ceramic-matrix composites, its spatial resolution must exceed 50 microns. Attention is given to two experimental data reconstructions that have been conducted to illustrate system capabilities.

  10. Case series of 64 slice computed tomography-computed tomographic angiography with 3D reconstruction to diagnose symptomatic cerebral aneurysms: new standard of care?

    Dietrich Jehle

    2012-02-01

    Full Text Available CT angiography (CTA has improved significantly over the past few years such that the reconstructed images of the cerebral arteries may now be equivalent to conventional digital angiography. The new technology of 64 slice multi-detector CTA can reconstruct detailed images that can reliably identify small cerebral aneurysms, even those <3mm. In addition, it is estimated that CT followed by lumbar puncture (LP misses up to 4% of symptomatic aneurysms. We present a series of cases that illustrates how CT followed by CTA may be replacing CT-LP as the standard of care in working up patients for symptomatic cerebral aneurysms and the importance of performing three dimensional (3D reconstructions. A series of seven cases of symptomatic cerebral aneurysms were identified that illustrate the sensitivity of CT-CTA versus CT-LP and the importance of 3D reconstruction in identifying these aneurysms. Surgical treatment was recommended for 6 of the 7 patients with aneurysms and strict hypertension control was recommended for the seventh patient. Some of these patients demonstrated subarachnoid hemorrhage on presentation while others had negative LPs. A number of these patients with negative LPs were clearly symptomatic from their aneurysms. At least one of these cerebral aneurysms was not apparent on CTA without 3D reconstruction. 3D reconstruction of CTA is crucial to adequately identify cerebral aneurysms. This case series helps reinforce the importance of 3D reconstruction. There is some data to suggest that 64 slice CT-CTA may be equivalent or superior to CT-LP in the detection of symptomatic cerebral aneurysms.

  11. Experimental computer tomograph

    Heinemann D.

    2015-09-01

    Full Text Available The computed tomography is one of the most important medical instruments, allowing the non-invasive visualization of cross sections which are free from superpositions. Since 2000 an experimental computer tomo-graph of the third generation for the purpose of education and research was set up and further developed. Besides the mechanical construction design reconstruction algorithms, including certain corrections of the measured data were developed and implemented. In 2013 iterative reconstruction methods were investigated and implemented for advanced reconstructions and dose reduction using various ray tracing algorithms. The new reconstruction technique leads to improvements in image quality and low dose reconstructions.

  12. The advantage of the three dimensional computed tomographic (3 D-CT for ensuring accurate bone incision in sagittal split ramus osteotomy

    Coen Pramono D

    2005-03-01

    Full Text Available Functional and aesthetic dysgnathia surgery requires accurate pre-surgical planning, including the surgical technique to be used related with the difference of anatomical structures amongst individuals. Programs that simulate the surgery become increasingly important. This can be mediated by using a surgical model, conventional x-rays as panoramic, cephalometric projections and another sophisticated method such as a three dimensional computed tomography (3 D-CT. A patient who had undergone double jaw surgeries with difficult anatomical landmarks was presented. In this case the mandible foramens were seen highly relatively related to the sigmoid notches. Therefore, ensuring the bone incisions in sagittal split was presumed to be difficult. A 3D-CT was made and considered to be very helpful in supporting the pre-operative diagnostic.

  13. 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

    Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Fritz, S., E-mail: stefan.fritz@med.uni-heidelberg.de [University Hospital Heidelberg, Department of General Visceral and Transplantation Surgery (Germany); Vollherbst, D., E-mail: dominikvollherbst@web.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Zelzer, S., E-mail: s.zelzer@dkfz-heidelberg.de [German Cancer Research Center (dkfz), Medical and Biological Informatics (Germany); Wachter, M. F., E-mail: fredericwachter@googlemail.com; Bellemann, N., E-mail: nadine.bellemann@med.uni-heidelberg.de; Gockner, T., E-mail: theresa.gockner@med.uni-heidelberg.de; Mokry, T., E-mail: theresa.mokry@med.uni-heidelberg.de; Schmitz, A., E-mail: anne.schmitz@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Aulmann, S., E-mail: sebastian.aulmann@mail.com [University Hospital Heidelberg, Department of General Pathology (Germany); Stampfl, U., E-mail: ulrike.stampfl@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Pereira, P., E-mail: philippe.pereira@slk-kliniken.de [SLK Kliniken Heilbronn GmbH, Clinic for Radiology, Minimally-invasive Therapies and Nuclear Medicine (Germany); Kauczor, H. U., E-mail: hu.kauczor@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Werner, J., E-mail: jens.werner@med.uni-heidelberg.de [University Hospital Heidelberg, Department of General Visceral and Transplantation Surgery (Germany); Radeleff, B. A., E-mail: boris.radeleff@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany)

    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.

  14. Computed tomographic findings of trichuriasis

    Naime Tokmak; Zafer Koc; Serife Ulusan; Ismail Soner Koltas; Nebil Bal

    2006-01-01

    In this report, we present computed tomographic findings of colonic trichuriasis. The patient was a 75-year-old man who complained of abdominal pain, and weight loss.Diagnosis was achieved by colonoscopic biopsy. Abdominal computed tomography showed irregular and nodular thickening of the wall of the cecum and ascending colon.Although these findings are nonspecific, they may be one of the findings of trichuriasis. These findings, confirmed by pathologic analysis of the biopsied tissue and KatoKatz parasitological stool flotation technique, revealed adult Trichuris. To our knowledge, this is the first report of colonic trichuriasis indicated by computed tomography.

  15. Post-processing methods of rendering and visualizing 3-D reconstructed tomographic images

    Wong, S.T.C. [Univ. of California, San Francisco, CA (United States)

    1997-02-01

    The purpose of this presentation is to discuss the computer processing techniques of tomographic images, after they have been generated by imaging scanners, for volume visualization. Volume visualization is concerned with the representation, manipulation, and rendering of volumetric data. Since the first digital images were produced from computed tomography (CT) scanners in the mid 1970s, applications of visualization in medicine have expanded dramatically. Today, three-dimensional (3D) medical visualization has expanded from using CT data, the first inherently digital source of 3D medical data, to using data from various medical imaging modalities, including magnetic resonance scanners, positron emission scanners, digital ultrasound, electronic and confocal microscopy, and other medical imaging modalities. We have advanced from rendering anatomy to aid diagnosis and visualize complex anatomic structures to planning and assisting surgery and radiation treatment. New, more accurate and cost-effective procedures for clinical services and biomedical research have become possible by integrating computer graphics technology with medical images. This trend is particularly noticeable in current market-driven health care environment. For example, interventional imaging, image-guided surgery, and stereotactic and visualization techniques are now stemming into surgical practice. In this presentation, we discuss only computer-display-based approaches of volumetric medical visualization. That is, we assume that the display device available is two-dimensional (2D) in nature and all analysis of multidimensional image data is to be carried out via the 2D screen of the device. There are technologies such as holography and virtual reality that do provide a {open_quotes}true 3D screen{close_quotes}. To confine the scope, this presentation will not discuss such approaches.

  16. 3D velocity measurements in a premixed flame by tomographic PIV

    Tokarev, M. P.; Sharaborin, D. K.; Lobasov, A. S.; Chikishev, L. M.; Dulin, V. M.; Markovich, D. M.

    2015-06-01

    Tomographic particle image velocimetry (PIV) has become a standard tool for 3D velocity measurements in non-reacting flows. However, the majority of the measurements in flows with combustion are limited to small resolved depth compared to the size of the field of view (typically 1 : 10). The limitations are associated with inhomogeneity of the volume illumination and the non-uniform flow seeding, the optical distortions and errors in the 3D calibration, and the unwanted flame luminosity. In the present work, the above constraints were overcome for the tomographic PIV experiment in a laminar axisymmetric premixed flame. The measurements were conducted for a 1 : 1 depth-to-size ratio using a system of eight CCD cameras and a 200 mJ pulsed laser. The results show that camera calibration based on the triangulation of the tracer particles in the non-reacting conditions provided reliable accuracy for the 3D image reconstruction in the flame. The modification of the tomographic reconstruction allowed a posteriori removal of unwanted bright objects, which were located outside of the region of interest but affected the reconstruction quality. This study reports on a novel experience for the instantaneous 3D velocimetry in laboratory-scale flames by using tomographic PIV.

  17. Parametrizable cameras for 3D computational steering

    Mulder, J.D.; Wijk, J.J. van

    1997-01-01

    We present a method for the definition of multiple views in 3D interfaces for computational steering. The method uses the concept of a point-based parametrizable camera object. This concept enables a user to create and configure multiple views on his custom 3D interface in an intuitive graphical man

  18. Dynamic 3D computed tomography scanner for vascular imaging

    Lee, Mark K.; Holdsworth, David W.; Fenster, Aaron

    2000-04-01

    A 3D dynamic computed-tomography (CT) scanner was developed for imaging objects undergoing periodic motion. The scanner system has high spatial and sufficient temporal resolution to produce quantitative tomographic/volume images of objects such as excised arterial samples perfused under physiological pressure conditions and enables the measurements of the local dynamic elastic modulus (Edyn) of the arteries in the axial and longitudinal directions. The system was comprised of a high resolution modified x-ray image intensifier (XRII) based computed tomographic system and a computer-controlled cardiac flow simulator. A standard NTSC CCD camera with a macro lens was coupled to the electro-optically zoomed XRII to acquire dynamic volumetric images. Through prospective cardiac gating and computer synchronized control, a time-resolved sequence of 20 mm thick high resolution volume images of porcine aortic specimens during one simulated cardiac cycle were obtained. Performance evaluation of the scanners illustrated that tomographic images can be obtained with resolution as high as 3.2 mm-1 with only a 9% decrease in the resolution for objects moving at velocities of 1 cm/s in 2D mode and static spatial resolution of 3.55 mm-1 with only a 14% decrease in the resolution in 3D mode for objects moving at a velocity of 10 cm/s. Application of the system for imaging of intact excised arterial specimens under simulated physiological flow/pressure conditions enabled measurements of the Edyn of the arteries with a precision of +/- kPa for the 3D scanner. Evaluation of the Edyn in the axial and longitudinal direction produced values of 428 +/- 35 kPa and 728 +/- 71 kPa, demonstrating the isotropic and homogeneous viscoelastic nature of the vascular specimens. These values obtained from the Dynamic CT systems were not statistically different (p less than 0.05) from the values obtained by standard uniaxial tensile testing and volumetric measurements.

  19. A 3D tomographic EBSD analysis of a CVD diamond thin film

    Tao Liu, Dierk Raabe and Stefan Zaefferer

    2008-01-01

    Full Text Available We have studied the nucleation and growth processes in a chemical vapor deposition (CVD diamond film using a tomographic electron backscattering diffraction method (3D EBSD. The approach is based on the combination of a focused ion beam (FIB unit for serial sectioning in conjunction with high-resolution EBSD. Individual diamond grains were investigated in 3-dimensions particularly with regard to the role of twinning.

  20. Computer Modelling of 3D Geological Surface

    Kodge, B G

    2011-01-01

    The geological surveying presently uses methods and tools for the computer modeling of 3D-structures of the geographical subsurface and geotechnical characterization as well as the application of geoinformation systems for management and analysis of spatial data, and their cartographic presentation. The objectives of this paper are to present a 3D geological surface model of Latur district in Maharashtra state of India. This study is undertaken through the several processes which are discussed in this paper to generate and visualize the automated 3D geological surface model of a projected area.

  1. 3D Computer Graphics and Nautical Charts

    Porathe, Thomas

    2011-01-01

    This paper gives an overview of an ongoing project using real-time 3D visualization to display nautical charts in a way used by 3D computer games. By displaying the map in an egocentric perspective the need to make cognitively demanding mental rotations are suggested to be removed, leading to faster decision-making and less errors. Experimental results support this hypothesis. Practical tests with limited success have been performed this year.

  2. Recovery and Visualization of 3D Structure of Chromosomes from Tomographic Reconstruction Images

    Tsap Leonid V

    2006-01-01

    Full Text Available The objectives of this work include automatic recovery and visualization of a 3D chromosome structure from a sequence of 2D tomographic reconstruction images taken through the nucleus of a cell. Structure is very important for biologists as it affects chromosome functions, behavior of the cell, and its state. Analysis of chromosome structure is significant in the detection of diseases, identification of chromosomal abnormalities, study of DNA structural conformation, in-depth study of chromosomal surface morphology, observation of in vivo behavior of the chromosomes over time, and in monitoring environmental gene mutations. The methodology incorporates thresholding based on a histogram analysis with a polyline splitting algorithm, contour extraction via active contours, and detection of the 3D chromosome structure by establishing corresponding regions throughout the slices. Visualization using point cloud meshing generates a 3D surface. The 3D triangular mesh of the chromosomes provides surface detail and allows a user to interactively analyze chromosomes using visualization software.

  3. Recovery and Visualization of 3D Structure of Chromosomes from Tomographic Reconstruction Images

    Babu, S; Liao, P; Shin, M C; Tsap, L V

    2004-04-28

    The objectives of this work include automatic recovery and visualization of a 3D chromosome structure from a sequence of 2D tomographic reconstruction images taken through the nucleus of a cell. Structure is very important for biologists as it affects chromosome functions, behavior of the cell and its state. Chromosome analysis is significant in the detection of deceases and in monitoring environmental gene mutations. The algorithm incorporates thresholding based on a histogram analysis with a polyline splitting algorithm, contour extraction via active contours, and detection of the 3D chromosome structure by establishing corresponding regions throughout the slices. Visualization using point cloud meshing generates a 3D surface. The 3D triangular mesh of the chromosomes provides surface detail and allows a user to interactively analyze chromosomes using visualization software.

  4. Deformable 3D-2D registration for CT and its application to low dose tomographic fluoroscopy

    Flach, Barbara; Brehm, Marcus; Sawall, Stefan; Kachelrieß, Marc

    2014-12-01

    Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D-3D) registration approaches can be applied. But research in temporal-correlated image reconstruction and dose reductions increases the number of cases where rawdata are available from only few projection angles. Here, deteriorated image quality leads to non-acceptable deformable volume-to-volume registration results. Therefore a registration approach is required that is robust against a decreasing number of projections defining the target position. We propose a deformable volume-to-rawdata (3D-2D) registration method that aims at finding a displacement vector field maximizing the alignment of a CT volume and the acquired rawdata based on the sum of squared differences in rawdata domain. The registration is constrained by a regularization term in accordance with a fluid-based diffusion. Both cost function components, the rawdata fidelity and the regularization term, are optimized in an alternating manner. The matching criterion is optimized by a conjugate gradient descent for nonlinear functions, while the regularization is realized by convolution of the vector fields with Gaussian kernels. We validate the proposed method and compare it to the demons algorithm, a well-known 3D-3D registration method. The comparison is done for a range of 4-60 target projections using datasets from low dose tomographic fluoroscopy as an application example. The results show a high correlation to the ground truth target position without introducing artifacts even in the case of very few projections. In particular the matching in the rawdata domain is improved compared to the 3D-3D registration for the investigated range. The proposed volume-to-rawdata registration increases the robustness regarding sparse

  5. A 3-D tomographic trajectory retrieval for the air-borne limb-imager GLORIA

    J. Ungermann

    2011-06-01

    Full Text Available Infrared limb sounding from aircraft can provide 2-D curtains of multiple trace gas species. However, conventional limb sounders view perpendicular to the aircraft axis and are unable to resolve the observed airmass along their line-of-sight. GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere is a new remote sensing instrument able to adjust its horizontal view angle with respect to the aircraft flight direction from 45° to 135°. This will allow for tomographic measurements of mesoscale structures for a wide variety of atmospheric constituents.

    Many flights of the GLORIA instrument will not follow closed curves that allow measuring an airmass from all directions. Consequently, it is examined by means of simulations, what results can be expected from tomographic evaluation of measurements made during a straight flight. It is demonstrated that the achievable resolution and stability is enhanced compared to conventional retrievals. In a second step, it is shown that the incorporation of channels exhibiting different optical depth can greatly enhance the 3-D retrieval quality enabling the exploitation of previously unused spectral samples.

    A second problem for tomographic retrievals is that advection, which can be neglected for conventional retrievals, plays an important role for the time-scales involved in a tomographic measurement flight. This paper presents a method to diagnose the effect of a time-varying atmosphere on a 3-D retrieval and demonstrates an effective way to compensate for effects of advection by incorporating wind-fields from meteorological datasets as a priori information.

  6. Radiation dose in neurological computed tomographic scanning

    Whitmore, R.C.; Bushong, S.C.; Archer, B.A.; Glaze, S.A.

    1979-07-01

    Patient dose and dose distribution during neurologicl computed tomography examinations were determined with five different computed tomography scanners. Maximum intracranial doses ranged from 1.17 to 2.67 rads. Doses to the lens of the eye ranged from 0.23 to 2.81 rads. These levels are considered and compared with patient doses reported for other computed tomography studies and for conventional tomographic examinations. In general, patient dose during computer tomographic examinations is less than one quarter of that during conventional tomography of the head.

  7. Molecular-Frame 3D Photoelectron Momentum Distributions by Tomographic Reconstruction

    Maurer, Jochen; Dimitrovski, Darko; Christensen, Lauge;

    2012-01-01

    Naphthalene molecules are fixed in space by a laser field and rotated, in 2° steps, over 180°. For each orientation, they are ionized by an intense, circularly polarized femtosecond laser pulse, and the 2D projection of the photoelectron momentum distribution is recorded. The molecular-frame 3D...... momentum distribution is obtained by tomographic reconstruction from all 90 projections. It reveals an anisotropic electron distribution, angularly shifted in the polarization plane, that is not accessible by the 2D momentum images. Our theoretical analysis shows that the magnitude of the angular shift...

  8. 3-D Tomographic Imaging of the Chicxulub Impact Crater: Preliminary Results From EW#0501

    Surendra, A. T.; Barton, P. J.; Vermeesch, P. M.; Morgan, J. V.; Warner, M. R.; Gulick, S. P.; Christeson, G. L.; Urrutia-Fucugauchi, J.; Rebolledo-Vieyra, M.; Melosh, H. J.; McDonald, M. A.; Goldin, T.; Mendoza, K.

    2005-05-01

    The Chicxulub impact structure provides a unique opportunity to investigate the sub-surface morphology of large craters on Earth and other planets. The structure of the crater interior is still poorly known and there is much uncertainty over the sequence of events by which these large craters form and the magnitude of the subsequent catastrophic environmental effects. In early 2005, a reflection-refraction survey aboard the R/V Maurice Ewing imaged the deep structure of the Chicxulub impact. We present wide-angle data collected by a 3-D grid of 50 ocean bottom seismometers (OBSs), 86 three-component land stations and a 6 km long hydrophone streamer. The OBS grid, designed to image the peak ring and underlying structure of the northwestern quadrant of the crater, recorded shots from several seismic profiles in various orientations. Many of these profiles extended past the crater rim imaging to the base of the crust. Travel-time picks from this dataset, combined with existing 1996 data, will be inverted using the JIVE3-D tomographic inversion program to create a fully 3-D velocity model of the crater interior. The interpretation of the velocity model will focus on the morphology of the peak ring and the central uplift, and the distribution of breccia and suevite (an impact related breccia/melt) in the centre of the crater. We will calculate the Poisson's ratio for different areas of the crater using both the P-wave velocity model and S-wave arrivals, including those from the 1996 land station data. Comparisons of these values with measurements on the Yaxcopoil-1 core taken from within the crater provide ground-truth for our tomographic model. The contrast in Poisson's ratio between areas of suevite and the surrounding rock further constrain the distribution of breccia and suevite.

  9. [Computer-assisted 3D phonetography].

    Neuschaefer-Rube, C; Klajman, S

    1996-10-01

    Profiles of fundamental frequency sound pressure levels and voice duration are measured separately in clinical practice. It was the aim of the present study to combine the two examinations, in order to estimate the relationship between pitch, sound pressure level and voice duration and to develop a new computer-assisted graph. A three-dimensional (3D) wireframe phonogram was constructed based on SPL profiles to obtain a general view of the parameters recorded. We have termed this "phonetography". Variable further projections were selected for the analysis of different aspects of parametric relationships. The results in 21 healthy volunteers and 4 patients with hyperfunctional dysphonias demonstrated that there were three typical figures of the 3D phonograms produced, depending on the relationship between voice duration when soft ("piano") compared to loud ("forte"). In one-third of the healthy volunteers, the values of the piano voice duration were greater than those of forte for almost all pitches examined. In two-thirds of the healthy subjects the values of forte voice duration were partly greater, as were those of piano voice duration. All of the patients showed voice duration values greater for forte than for piano. The results of the study demonstrate that the 3D phonogram is a useful tool for obtaining new insights into various relationships of voice parameters.

  10. Practical algorithms for 3D computer graphics

    Ferguson, R Stuart

    2013-01-01

    ""A valuable book to accompany any course that mixes the theory and practice of 3D graphics. The book's web site has many useful programs and code samples.""-Karen Rafferty, Queen's University, Belfast""The topics covered by this book are backed by the OpenFX modeling and animation software. This is a big plus in that it provides a practical perspective and encourages experimentation. … [This] will offer students a more interesting and hands-on learning experience, especially for those wishing to pursue a career in computer game development.""-Naganand Madhavapeddy, GameDeveloper>

  11. Computed tomographic appearances of sternocostoclavicular hyperostosis

    Chigira, Masaki; Shimizu, Toru (Gunma Univ. (Japan). Dept. of Orthopaedic Surgery)

    1989-08-01

    Computed tomographical analysis of sternocostoclavicular hyperostosis was performed in 27 patients. In the earliest stage hyperostosis occurred around the cartilaginous portion of the first ribs. The sternoclavicular joint space was preserved even in the late stage III of the disorder. It is also suggested that perichondritis and periostitis play important roles in the etiology of this disorder. (orig./GDG).

  12. Estimation of the thermal conductivity of hemp based insulation material from 3D tomographic images

    El-Sawalhi, R.; Lux, J.; Salagnac, P.

    2016-08-01

    In this work, we are interested in the structural and thermal characterization of natural fiber insulation materials. The thermal performance of these materials depends on the arrangement of fibers, which is the consequence of the manufacturing process. In order to optimize these materials, thermal conductivity models can be used to correlate some relevant structural parameters with the effective thermal conductivity. However, only a few models are able to take into account the anisotropy of such material related to the fibers orientation, and these models still need realistic input data (fiber orientation distribution, porosity, etc.). The structural characteristics are here directly measured on a 3D tomographic image using advanced image analysis techniques. Critical structural parameters like porosity, pore and fiber size distribution as well as local fiber orientation distribution are measured. The results of the tested conductivity models are then compared with the conductivity tensor obtained by numerical simulation on the discretized 3D microstructure, as well as available experimental measurements. We show that 1D analytical models are generally not suitable for assessing the thermal conductivity of such anisotropic media. Yet, a few anisotropic models can still be of interest to relate some structural parameters, like the fiber orientation distribution, to the thermal properties. Finally, our results emphasize that numerical simulations on 3D realistic microstructure is a very interesting alternative to experimental measurements.

  13. Tomographic active optical trapping of arbitrarily shaped objects by exploiting 3-D refractive index maps

    Kim, Kyoohyun

    2016-01-01

    Optical trapping can be used to manipulate the three-dimensional (3-D) motion of spherical particles based on the simple prediction of optical forces and the responding motion of samples. However, controlling the 3-D behaviour of non-spherical particles with arbitrary orientations is extremely challenging, due to experimental difficulties and the extensive computations. Here, we achieved the real-time optical control of arbitrarily shaped particles by combining the wavefront shaping of a trapping beam and measurements of the 3-D refractive index (RI) distribution of samples. Engineering the 3-D light field distribution of a trapping beam based on the measured 3-D RI map of samples generates a light mould, which can be used to manipulate colloidal and biological samples which have arbitrary orientations and/or shapes. The present method provides stable control of the orientation and assembly of arbitrarily shaped particles without knowing a priori information about the sample geometry. The proposed method can ...

  14. GPU-based rapid reconstruction of cellular 3D refractive index maps from tomographic phase microscopy (Conference Presentation)

    Dardikman, Gili; Shaked, Natan T.

    2016-03-01

    We present highly parallel and efficient algorithms for real-time reconstruction of the quantitative three-dimensional (3-D) refractive-index maps of biological cells without labeling, as obtained from the interferometric projections acquired by tomographic phase microscopy (TPM). The new algorithms are implemented on the graphic processing unit (GPU) of the computer using CUDA programming environment. The reconstruction process includes two main parts. First, we used parallel complex wave-front reconstruction of the TPM-based interferometric projections acquired at various angles. The complex wave front reconstructions are done on the GPU in parallel, while minimizing the calculation time of the Fourier transforms and phase unwrapping needed. Next, we implemented on the GPU in parallel the 3-D refractive index map retrieval using the TPM filtered-back projection algorithm. The incorporation of algorithms that are inherently parallel with a programming environment such as Nvidia's CUDA makes it possible to obtain real-time processing rate, and enables high-throughput platform for label-free, 3-D cell visualization and diagnosis.

  15. Evolution of residual stress and crack morphologies during 3D FIB tomographic analysis of alumina.

    Elfallagh, F; Inkson, B J

    2008-05-01

    Three-dimensional focused ion beam (FIB) tomography is increasingly being used for 3D characterization of microstructures in the 50 nm-20 microm range. FIB tomography is a destructive, invasive process, and microstructural changes may potentially occur during the analysis process. Here residual stress and crack morphologies in single-crystal sapphire samples have been concurrently analyzed using Cr3+ fluorescence spectroscopy and FIB tomography. Specifically, maps of surface residual stress have been obtained from optically polished single-crystal alumina [surface orientation (1 ī 0 2)], from FIB milled surface trenches, from Vickers micro-indentation sites (loads 50 g-300 g), and from Vickers micro-indentation sites during FIB serial sectioning. The residual stress maps clearly show that FIB sputtering generates residual stress changes. For the case of the Vickers micro-indentations, FIB sputtering causes significant changes in residual stress during the FIB tomographic serial sectioning. 3D reconstruction of the crack distribution around micro-indentation sites shows that the cracks observed are influenced by the location of the FIB milled surface trenches due to localized stress changes.

  16. Computed tomographic colonography:Hope or hype?

    Otto; Schiueh-Tzang; Lin

    2010-01-01

    Computed tomographic colonography (CTC) is a promising emerging technology for imaging of the colon. This concise review discusses the currently available data on CTC technique,test characteristics,acceptance,safety,cost-effectiveness,follow-up strategy,and extracolonic findings. In summary,CTC technique is still evolving,and further research is needed to clarify the role of automated colonic insufflation,smooth-muscle relaxants,intravenous and oral contrast,soft-ware rendering,and patient positioning. Curr...

  17. Cranial computed tomographic abnormalities in leptomeningeal metastasis

    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.

  18. Computed tomographic findings in acute infantile hemiplegia

    Hisanaga, M.; Utsumi, S.; Kyoi, K.; Gega, A.; Tanikake, T. (Nara Medical Univ., Kashihara (Japan))

    1981-06-01

    The clinical and computed tomographic findings in four cases of acute infantile hemiplegia that were followed for over ten years are described. The most impressive and common findings in four cases are as follows: 1) Unilateral loss of cerebral volume with displacement of the midline structures to the affected side. 2) Unilateral thicked calvarium and dilated frontal and ethmoid sinus and mastoid air cells on affected side. 3) A dilated lateral ventricle in the affected hemisphere. The recognition of these calvarial changes should indicate that the cerebral abnormalities are the result of an atrophic and hypoplastic process that began in early life.

  19. 3D flow visualization and tomographic particle image velocimetry for vortex breakdown over a non-slender delta wing

    Wang, ChengYue; Gao, Qi; Wei, RunJie; Li, Tian; Wang, JinJun

    2016-06-01

    Volumetric measurement for the leading-edge vortex (LEV) breakdown of a delta wing has been conducted by three-dimensional (3D) flow visualization and tomographic particle image velocimetry (TPIV). The 3D flow visualization is employed to show the vortex structures, which was recorded by four cameras with high resolution. 3D dye streaklines of the visualization are reconstructed using a similar way of particle reconstruction in TPIV. Tomographic PIV is carried out at the same time using same cameras with the dye visualization. Q criterion is employed to identify the LEV. Results of tomographic PIV agree well with the reconstructed 3D dye streaklines, which proves the validity of the measurements. The time-averaged flow field based on TPIV is shown and described by sections of velocity and streamwise vorticity. Combining the two measurement methods sheds light on the complex structures of both bubble type and spiral type of breakdown. The breakdown position is recognized by investigating both the streaklines and TPIV velocity fields. Proper orthogonal decomposition is applied to extract a pair of conjugated helical instability modes from TPIV data. Therefore, the dominant frequency of the instability modes is obtained from the corresponding POD coefficients of the modes based on wavelet transform analysis.

  20. Infra Red 3D Computer Mouse

    Harbo, Anders La-Cour; Stoustrup, Jakob

    2000-01-01

    of bandwidth, the signals are designed by means of the wavelet and the Rudin-Shapiro transforms. This also allows for easy separation of simultaneously made measurements. The measured intensities are converted to an 3D position by a neural net. The principle also applies to other applications, for instance...

  1. Fusion of terrestrial LiDAR and tomographic mapping data for 3D karst landform investigation

    Höfle, B.; Forbriger, M.; Siart, C.; Nowaczinski, E.

    2012-04-01

    Highly detailed topographic information has gained in importance for studying Earth surface landforms and processes. LiDAR has evolved into the state-of-the-art technology for 3D data acquisition on various scales. This multi-sensor system can be operated on several platforms such as airborne LS (ALS), mobile LS (MLS) from moving vehicles or stationary on ground (terrestrial LS, TLS). In karst research the integral investigation of surface and subsurface components of solution depressions (e.g. sediment-filled dolines) is required to gather and quantify the linked geomorphic processes such as sediment flux and limestone dissolution. To acquire the depth of the different subsurface layers, a combination of seismic refraction tomography (SRT) and electrical resistivity tomography (ERT) is increasingly applied. This multi-method approach allows modeling the extension of different subsurface media (i.e. colluvial fill, epikarst zone and underlying basal bedrock). Subsequent fusion of the complementary techniques - LiDAR surface and tomographic subsurface data - first-time enables 3D prospection and visualization as well as quantification of geomorphometric parameters (e.g. depth, volume, slope and aspect). This study introduces a novel GIS-based method for semi-automated fusion of TLS and geophysical data. The study area is located in the Dikti Mountains of East Crete and covers two adjacent dolines. The TLS data was acquired with a Riegl VZ-400 scanner from 12 scan positions located mainly at the doline divide. The scan positions were co-registered using the iterative closest point (ICP) algorithm of RiSCAN PRO. For the digital elevation rasters a resolution of 0.5 m was defined. The digital surface model (DSM) of the study was derived by moving plane interpolation of all laser points (including objects) using the OPALS software. The digital terrain model (DTM) was generated by iteratively "eroding" objects in the DSM by minimum filter, which additionally accounts for

  2. Computed Tomographic Perfusion Improves Diagnostic Power of Coronary Computed Tomographic Angiography in Women

    Penagaluri, Ashritha; Higgins, Angela Y; Vavere, Andrea L

    2016-01-01

    BACKGROUND: Coronary computed tomographic angiography (CTA) and myocardial perfusion imaging (CTP) is a validated approach for detection and exclusion of flow-limiting coronary artery disease (CAD), but little data are available on gender-specific performance of these modalities. In this study, w...... REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00934037....

  3. Imaging of 3-D seismic velocity structure of Southern Sumatra region using double difference tomographic method

    Lestari, Titik, E-mail: t2klestari@gmail.com [Meteorological Climatological and Geophysical Agency (MCGA), Jalan Angkasa I No.2 Kemayoran, Jakarta Pusat, 10720 (Indonesia); Faculty of Earth Science and Technology, Bandung Institute of Technology, Jalan Ganesa No.10, Bandung 40132 (Indonesia); Nugraha, Andri Dian, E-mail: nugraha@gf.itb.ac.id [Global Geophysical Research Group, Faculty of Mining and Petroleum Engineering, Bandung Institute of Technology, Jalan Ganesa 10 Bandung 40132 (Indonesia)

    2015-04-24

    Southern Sumatra region has a high level of seismicity due to the influence of the subduction system, Sumatra fault, Mentawai fault and stretching zone activities. The seismic activities of Southern Sumatra region are recorded by Meteorological Climatological and Geophysical Agency (MCGA’s) Seismograph network. In this study, we used earthquake data catalog compiled by MCGA for 3013 events from 10 seismic stations around Southern Sumatra region for time periods of April 2009 – April 2014 in order to invert for the 3-D seismic velocities structure (Vp, Vs, and Vp/Vs ratio). We applied double-difference seismic tomography method (tomoDD) to determine Vp, Vs and Vp/Vs ratio with hypocenter adjustment. For the inversion procedure, we started from the initial 1-D seismic velocity model of AK135 and constant Vp/Vs of 1.73. The synthetic travel time from source to receiver was calculated using ray pseudo-bending technique, while the main tomographic inversion was applied using LSQR method. The resolution model was evaluated using checkerboard test and Derivative Weigh Sum (DWS). Our preliminary results show low Vp and Vs anomalies region along Bukit Barisan which is may be associated with weak zone of Sumatran fault and migration of partial melted material. Low velocity anomalies at 30-50 km depth in the fore arc region may indicated the hydrous material circulation because the slab dehydration. We detected low seismic seismicity in the fore arc region that may be indicated as seismic gap. It is coincides contact zone of high and low velocity anomalies. And two large earthquakes (Jambi and Mentawai) also occurred at the contact of contrast velocity.

  4. Imaging of 3-D seismic velocity structure of Southern Sumatra region using double difference tomographic method

    Lestari, Titik; Nugraha, Andri Dian

    2015-04-01

    Southern Sumatra region has a high level of seismicity due to the influence of the subduction system, Sumatra fault, Mentawai fault and stretching zone activities. The seismic activities of Southern Sumatra region are recorded by Meteorological Climatological and Geophysical Agency (MCGA's) Seismograph network. In this study, we used earthquake data catalog compiled by MCGA for 3013 events from 10 seismic stations around Southern Sumatra region for time periods of April 2009 - April 2014 in order to invert for the 3-D seismic velocities structure (Vp, Vs, and Vp/Vs ratio). We applied double-difference seismic tomography method (tomoDD) to determine Vp, Vs and Vp/Vs ratio with hypocenter adjustment. For the inversion procedure, we started from the initial 1-D seismic velocity model of AK135 and constant Vp/Vs of 1.73. The synthetic travel time from source to receiver was calculated using ray pseudo-bending technique, while the main tomographic inversion was applied using LSQR method. The resolution model was evaluated using checkerboard test and Derivative Weigh Sum (DWS). Our preliminary results show low Vp and Vs anomalies region along Bukit Barisan which is may be associated with weak zone of Sumatran fault and migration of partial melted material. Low velocity anomalies at 30-50 km depth in the fore arc region may indicated the hydrous material circulation because the slab dehydration. We detected low seismic seismicity in the fore arc region that may be indicated as seismic gap. It is coincides contact zone of high and low velocity anomalies. And two large earthquakes (Jambi and Mentawai) also occurred at the contact of contrast velocity.

  5. A 3-D tomographic retrieval approach with advection compensation for the air-borne limb-imager GLORIA

    J. Ungermann

    2011-11-01

    Full Text Available Infrared limb sounding from aircraft can provide 2-D curtains of multiple trace gas species. However, conventional limb sounders view perpendicular to the aircraft axis and are unable to resolve the observed airmass along their line-of-sight. GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere is a new remote sensing instrument that is able to adjust its horizontal view angle with respect to the aircraft flight direction from 45° to 135°. This will allow for tomographic measurements of mesoscale structures for a wide variety of atmospheric constituents.

    Many flights of the GLORIA instrument will not follow closed curves that allow measuring an airmass from all directions. Consequently, it is examined by means of simulations, what spatial resolution can be expected under ideal conditions from tomographic evaluation of measurements made during a straight flight. It is demonstrated that the achievable horizontal resolution in the line-of-sight direction could be reduced from over 200 km to around 70 km compared to conventional retrievals and that the tomographic retrieval is also more robust against horizontal gradients in retrieved quantities in this direction. In a second step, it is shown that the incorporation of channels exhibiting different optical depth can further enhance the spatial resolution of 3-D retrievals enabling the exploitation of spectral samples usually not used for limb sounding due to their opacity.

    A second problem for tomographic retrievals is that advection, which can be neglected for conventional retrievals, plays an important role for the time-scales involved in a tomographic measurement flight. This paper presents a method to diagnose the effect of a time-varying atmosphere on a 3-D retrieval and demonstrates an effective way to compensate for effects of advection by incorporating wind-fields from meteorological datasets as a priori information.

  6. E-learn Computed Tomographic Angiography

    Havsteen, Inger; Christensen, Anders; Nielsen, Jens K;

    2012-01-01

    BACKGROUND: Computed tomographic angiography (CTA) is widely available in emergency rooms to assess acute stroke patients. To standardize readings and educate new readers, we developed a 3-step e-learning tool based on the test-teach-retest methodology in 2 acute stroke scenarios: vascular...... occlusion and "spot sign" in acute intracerebral hemorrhage. We hypothesized that an e-learning program enhances reading skills in physicians of varying experience. METHODS: We developed an HTML-based program with a teaching segment and 2 matching test segments. Tests were taken before and after...... sign correctly 69% before versus 92% after teaching (P = .009) and reported a median self-perceived diagnostic certainty of 50% versus 75% (P = .030). Self-perceived diagnostic certainty revealed no significant increase for vascular occlusion. CONCLUSIONS: The e-learning program is a useful educational...

  7. Estimation of water saturated permeability of soils, using 3D soil tomographic images and pore-level transport phenomena modelling

    Lamorski, Krzysztof; Sławiński, Cezary; Barna, Gyöngyi

    2014-05-01

    There are some important macroscopic properties of the soil porous media such as: saturated permeability and water retention characteristics. These soil characteristics are very important as they determine soil transport processes and are commonly used as a parameters of general models of soil transport processes used extensively for scientific developments and engineering practise. These characteristics are usually measured or estimated using some statistical or phenomenological modelling, i.e. pedotransfer functions. On the physical basis, saturated soil permeability arises from physical transport processes occurring at the pore level. Current progress in modelling techniques, computational methods and X-ray micro-tomographic technology gives opportunity to use direct methods of physical modelling for pore level transport processes. Physically valid description of transport processes at micro-scale based on Navier-Stokes type modelling approach gives chance to recover macroscopic porous medium characteristics from micro-flow modelling. Water microflow transport processes occurring at the pore level are dependent on the microstructure of porous body and interactions between the fluid and the medium. In case of soils, i.e. the medium there exist relatively big pores in which water can move easily but also finer pores are present in which water transport processes are dominated by strong interactions between the medium and the fluid - full physical description of these phenomena is a challenge. Ten samples of different soils were scanned using X-ray computational microtomograph. The diameter of samples was 5 mm. The voxel resolution of CT scan was 2.5 µm. Resulting 3D soil samples images were used for reconstruction of the pore space for further modelling. 3D image threshholding was made to determine the soil grain surface. This surface was triangulated and used for computational mesh construction for the pore space. Numerical modelling of water flow through the

  8. CASTLE3D - A Computer Aided System for Labelling Archaeological Excavations in 3D

    Houshiar, H.; Borrmann, D.; Elseberg, J.; Nüchter, A.; Näth, F.; Winkler, S.

    2015-08-01

    Documentation of archaeological excavation sites with conventional methods and tools such as hand drawings, measuring tape and archaeological notes is time consuming. This process is prone to human errors and the quality of the documentation depends on the qualification of the archaeologist on site. Use of modern technology and methods in 3D surveying and 3D robotics facilitate and improve this process. Computer-aided systems and databases improve the documentation quality and increase the speed of data acquisition. 3D laser scanning is the state of the art in modelling archaeological excavation sites, historical sites and even entire cities or landscapes. Modern laser scanners are capable of data acquisition of up to 1 million points per second. This provides a very detailed 3D point cloud of the environment. 3D point clouds and 3D models of an excavation site provide a better representation of the environment for the archaeologist and for documentation. The point cloud can be used both for further studies on the excavation and for the presentation of results. This paper introduces a Computer aided system for labelling archaeological excavations in 3D (CASTLE3D). Consisting of a set of tools for recording and georeferencing the 3D data from an excavation site, CASTLE3D is a novel documentation approach in industrial archaeology. It provides a 2D and 3D visualisation of the data and an easy-to-use interface that enables the archaeologist to select regions of interest and to interact with the data in both representations. The 2D visualisation and a 3D orthogonal view of the data provide cuts of the environment that resemble the traditional hand drawings. The 3D perspective view gives a realistic view of the environment. CASTLE3D is designed as an easy-to-use on-site semantic mapping tool for archaeologists. Each project contains a predefined set of semantic information that can be used to label findings in the data. Multiple regions of interest can be joined under

  9. [Upper airway's 3D analysis of patients with obstructive sleep apnea using tomographic cone beam].

    Bruwier, A; Poirrier, A L; Limme, M; Poirrier, R

    2014-12-01

    The progress of medical imaging over the last decades has led to a better understanding of the upper airway structure in sleep-disordered patients. The Obstructive Sleep Apnea Syndrome (OSA) is attributed to a functional narrowing of the upper airway, particularly of the oropharynx, during sleep. This narrowing is multifactorial. We have shown that in 60% cases, the maxilla (nasal pyramid) seems too narrow. A mandible retroposition may also play a dominant role in 30% of the cases. Both scenarios can be combined. Cone Beam Computed Tomography (CBCT) is a new medical imaging technique that permits to visualize the upper airway with less ionizing radiation than the conventional scanner. To date, only five authors have performed an upper airway's 3D analysis of sleep apnea patients with cone beam. A better understanding of the affected segment of the upper airway should help refine treatment options.

  10. Computer animation for articulated 3D characters

    Kiss, S.

    2002-01-01

    We present a review of the computer animation literature, mainly concentrating on articulated characters and at least some degree of interactivity or real time simulation. Advances in dierent techniques such as key-frame, motion capture (also known as mocap), dynamics, inverse kinematics (IK), contr

  11. Computed tomographic anatomy of the equine foot.

    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.

  12. 3D organization of high-speed compressible jets by tomographic PIV

    Violato, D.; Ceglia, G.; Tuinstra, M.; Scarano, F.

    2013-01-01

    This work investigates the three dimensional organization of compressible jets at high-speed regime by tomographic particle image velocimetry (TOMO PIV). Experiments are conducted at Mach numbers 0.3, 0.9 and 1.1 (underexpanded regime) across the end of the potential core within a large cylindrica

  13. Towards 3C-3D digital holographic fluid velocity vector field measurement—tomographic digital holographic PIV (Tomo-HPIV)

    Soria, J.; Atkinson, C.

    2008-07-01

    Most unsteady and/or turbulent flows of geophysical and engineering interest have a highly three-dimensional (3D) complex topology and their experimental investigation is in pressing need of quantitative velocity measurement methods that are robust and can provide instantaneous 3C-3D velocity field data over a significant volumetric domain of the flow. This paper introduces and demonstrates a new method that uses multiple digital CCD array cameras to record in-line digital holograms of the same volume of seed particles from multiple orientations. This technique uses the same basic equipment as Tomo-PIV minus the camera lenses, it overcomes the depth-of-field problem of digital in-line holography and does not require the complex optical calibration of Tomo-PIV. The digital sensors can be oriented in an optimal manner to overcome the depth-of-field limitation of in-line holograms recorded using digital CCD or CMOS array cameras, resulting in a 3D reconstruction of the seed particles within the volume of interest, which can subsequently be analysed using 3D cross-correlation PIV analysis to yield a 3C-3D velocity field. A demonstration experiment of Tomo-HPIV using uniform translation with nominally 11 µm diameter seed particles shows that the 3D displacement derived from 3D cross-correlation Tomo-HPIV analysis can be measured within 5% of the imposed uniform translation, where the imposed uniform translation has an estimated standard uncertainty of 4.3%. So this paper proposes a multi-camera digital holographic imaging 3C-3D PIV method, which is identified as tomographic digital holographic PIV or Tomo-HPIV.

  14. Computed tomographic findings of cerebral paragonimiasis

    Sung, Nak Kwan; Nam, Kyung Jin; Park, Churl Min; Eun, Chung Kie; Lee, Sun Wha [Kyung Hee Unversity Hospital, Seoul (Korea, Republic of)

    1983-03-15

    Paragonimiasis is widely distributed in Far East and Southeast Asia, particularly in Korea. The central nervous system is the most frequent location for paragonimiasis outside the lungs. We analyzed the computed tomographic findings of 17 cases which were diagnosed pathologically and clinically as cerebral paragonimiasis. The results were as follows: 1. The ratio of male to female was 10 : 7 and about 88% of cases were under the age of 40 years. 2. The common locations of cerebral paragonimiasis were the occipital (12 cases) and temporal (11 cases) lobes. 3. Precontrast CT findings of cerebral paragonimiasis were low density with calcifications in 6 cases, low and isodensities in 4 cases, mixed densities in 3 cases, only low density in 2 cases and only calcification in 2 cases. Hydrocephalus (7 cases), mass effect (6 cases), atrophic change (6 cases) and cyst formation (3 cases) were associated. 4. The shape of calcifications in CT scan were soap-bubble or ring in 6 cases, nodular or oval in 6 cases, stipple in 4 cases and amorphous conglomerated in 2 cases. 5. The contrast -enhanced 8 cases were 5 ring or rim like, 2 nodular and 1 irregular enhancements, while 9 cases were not enhanced.

  15. Computed tomographic findings of intracerebral cysticercosis

    Hong, Jin Kyo; Lee, Sun Wha; Kim, Ho Kyun; Ahn, Chi Yul [School of Medicine, Kyung-Hee University, Seoul (Korea, Republic of)

    1980-12-15

    Cysticercosis is a parasitic disease in which man serves as the intermediate host of Taenia Solium, the pork tapeworm. The computed tomographic findings of 25 cases of intracerebral cysticercosis proven by pathologic and/or clinical findings during past 2 years were analysed. The results were as follows; 1. The sex was 19 males and 6 females, and 56 percent of the patients were seen in fourth and fifth decades. The most common symptom was epilepsy (72%). 2. The C. T. findings in precontrast study were varied; such as ill defined low density (48%), cystic low density (20%), dilated ventricles (20%), ill defined low density with isodense nodule (18%), cystic low density with isodense mural nodule (12%) and calcification (8%). 3. The areas of involvement were 20 cases (80%) of parenchymal form, 3 cases (12%) of ventricular form and 2 cases (8%) of mixed form. 4. The contrast-enhanced 13 cases were 5 nodular, 5 ring or rim-like and 3 mixed type enhancements, while 12 cases were not enhanced. 5. C.T. scan demonstrated more precise location and extents of cerebral cysticercosis, especially in parenchymal form. It was considered to be important in determination of surgical feasibility and its approach.

  16. Computed tomographic findings in orbital Mucor

    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.

  17. Computed tomographic findings of cerebral paragonimiasis

    Bae, Weon Tae; Jung, Min Ki; Kang, Heoung Keun; Chung, Hyon De [Chonnam University Medicine School, Gwangju (Korea, Republic of)

    1988-10-15

    Authors analyzed the computed tomographic (CT) findings of 19 cases pathologically and clinically proven cerebral paragonimiasis that were performed at Chonnam University Hospital from April 1983 through March 1987. The results were as follows: 1. Male to female ratio was 15:4 and the most prevalent age group was 3rd decade (7 cases). The common symptoms were epileptic seizure (16 cases) and headache (12 cases). 2. The multiplicity of cerebral paragonimiasis was 7 of 19 cases and the distributions of lesion were occipital (11 cases), temporal (6 cases), frontal (5 cases) and parietal (5 cases) lobe. 3. The calcification on CT scan were single (7 cases) or multiple (7 cases) and the shape of calcification were nodular (10 cases), soap babble of ring (8 cases), and stippled (6 cases). The pattern of contrast enhancement were ring (5 cases) or nodular (1 case), and along the basal cistern (1 case with arachnoiditis). 4. 12 out of 13 cases, had long clinical symptoms over 3 years with calcifications, could be analyzed according to Valentine's vascular territory; 6 cases in PCA territory, 3 in MCA and 3 in ACA. 5. CT findings were noted according to the duration of symptoms; 5 cases, had symptoms less than 1 year, showed abscess (5 cases) and arachnoiditis (1 case) with brain edema, mass effect, hydrocephalus and contrast enhancement but no calcification in all. One case, had symptom of 1 year and 2 months, showed partially calcified granulomatous lesion with perifocal edema and contrast enhancement, 13 cases, had symptoms over 3 years, showed multiple calcification with brain atrophy (10 cases), but no contrast enhancement in all cases.

  18. Computer simulations of a low energy proton beam tomograph

    Milhoretto, E.; Schelin, H.R.; Setti, J.A.P.; Denyak, V.; Paschuk, S.A.; Basilio, A.C.; Rocha, R.; Ribeiro Junior, S. [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Curso de Pos-Graduacao em Engenharia Eletrica e Informatica Industrial (CPGEI)]. E-mails: sergei@utfpr.edu.br; edneymilhoretto@yahoo.com; schelin@cpgei.cefetpr.br; Evseev, I.; Yevseyeva, O. [Universidade Estadual do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil)]. E-mail: evseev@iprj.uerj.br; Lopes, R.T. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graducao em Engenharia (COPPE). Lab. de Instrumentacao Nuclear]. E-mail: ricardo@lin.ufrj.br; Vinagre Filho, U.M. [Instituto de Energia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2007-07-01

    This work presents the recent development of a low energy proton beam tomograph. The proton tomograph prototype (involving UTFPR, UERJ, UFRJ and IEN/CNEN) has been installed and tested at the cyclotron CV-28 of IEN/CNEN. New computer simulations were performed in order to optimize the performance of the scattered proton beam and its aluminum collimator energy losses. The computer code simulates the tomographic measurements with two aluminum collimators (variable aperture from 0.2 mm to 0.4 mm in diameter and variable thickness from 4 mm to 8 mm), a water phantom and a Si(Li) detector. The analysis of the exit beam energy spectra in comparison with a perfectly collimated proton beam made it possible to achieve the best quality of reconstructed tomographic images of water phantom. (author)

  19. Evaluation of multislice computed tomographic perfusion imaging and computed tomographic angiography on traumatic cerebral infarction

    XU Fang-hong; CHEN Wei-jian; YANG Yun-jun; DUAN Yu-xia; FU Feng-li

    2008-01-01

    Objective: To evaluate the application value of multislice computed tomographic perfusion imaging (MSCTPI) and multislice computed tomographic angiography (MSCTA) on traumatic cerebral infarction. Methods: MSCTA was performed on 10 patients who were initiailly diagnosed as traumatic cerebral infarction by normal conventional computed tomography (NCCT), among whom, 3 patients were examined by MSCTPI simultaneously. Reconstructed images of the intracranial artery were made with techniques of maximum intensity projection (MIP) and volume rendering (VR) from MSCTA scanning data. Then the graph of function of four parameters, regional cerebral blood flow (Rcbf), regional cerebral blood volume (Rcbv), mean transit time (MTT), and time to peak (TTP), acquired by the perfusing analysis software was obtained. Results: Among the 10 patients with traumatic cerebral infarction, 6 showed complex type on NCCT, which depicted abnormality on MSCTA, and 4 showed simple type on NCCT, which had negative results on MSCTA. Among the 4 patients with abnormal great vessels, 2 suffered from steno sis or occlusion of the middle cerebral artery, 1 from spasm of the anterior cerebral artery, and 1 from spasm of the vertebral-basal artery. The image of MSCTPI of 1 patient with massive cerebral infarction on the right cerebral hemisphere confirmed by CT was smaller than those of the other patients, which showed occlusion of the ipsilateral middle cerebral artery on MSCTA. Among the 6 patients whose MSCTA showed no abnormality, 4 showed simple infarction and 2 showed complex infarction. The infarction focus of 5 patients occurred in the basal ganglia and 1 in the splenium of corpus callosum. Among the 2 cases of small cerebral infarction volume on NCCT, one was normal, the other showed hypoperfusion on MSCTPI and was normal on MSCTA. Conclusion: The combination of MSCTPI and MSCTA is very useful for evaluating the change of intracranial artery in ischemic regions and assessing the cerebral

  20. 3D measurement system based on computer-generated gratings

    Zhu, Yongjian; Pan, Weiqing; Luo, Yanliang

    2010-08-01

    A new kind of 3D measurement system has been developed to achieve the 3D profile of complex object. The principle of measurement system is based on the triangular measurement of digital fringe projection, and the fringes are fully generated from computer. Thus the computer-generated four fringes form the data source of phase-shifting 3D profilometry. The hardware of system includes the computer, video camera, projector, image grabber, and VGA board with two ports (one port links to the screen, another to the projector). The software of system consists of grating projection module, image grabbing module, phase reconstructing module and 3D display module. A software-based synchronizing method between grating projection and image capture is proposed. As for the nonlinear error of captured fringes, a compensating method is introduced based on the pixel-to-pixel gray correction. At the same time, a least square phase unwrapping is used to solve the problem of phase reconstruction by using the combination of Log Modulation Amplitude and Phase Derivative Variance (LMAPDV) as weight. The system adopts an algorithm from Matlab Tool Box for camera calibration. The 3D measurement system has an accuracy of 0.05mm. The execution time of system is 3~5s for one-time measurement.

  1. 3D artefact for concurrent scale calibration in Computed Tomography

    Stolfi, Alessandro; De Chiffre, Leonardo

    2016-01-01

    A novel artefact for calibration of the scale in 3D X-ray Computed Tomography (CT) is presented. The artefact comprises a carbon fibre tubular structure on which a number of reference ruby spheres are glued. The artefact is positioned and scanned together with the workpiece inside the CT scanner ...

  2. Full-wave Moment Tensor and Tomographic Inversions Based on 3D Strain Green Tensor

    2010-01-31

    out on a Beowulf PC cluster purchased with a grant from the National Science Foundation. This work would not be possible without the creativity and...J. Ritsema, and J. Tromp, The spectral-element method, Beowulf computing, and global seismology, Science 298, 1737-1742, 2002. Li, X., and B

  3. NASA's 3D Flight Computer for Space Applications

    Alkalai, Leon

    2000-01-01

    The New Millennium Program (NMP) Integrated Product Development Team (IPDT) for Microelectronics Systems was planning to validate a newly developed 3D Flight Computer system on its first deep-space flight, DS1, launched in October 1998. This computer, developed in the 1995-97 time frame, contains many new computer technologies previously never used in deep-space systems. They include: advanced 3D packaging architecture for future low-mass and low-volume avionics systems; high-density 3D packaged chip-stacks for both volatile and non-volatile mass memory: 400 Mbytes of local DRAM memory, and 128 Mbytes of Flash memory; high-bandwidth Peripheral Component Interface (Per) local-bus with a bridge to VME; high-bandwidth (20 Mbps) fiber-optic serial bus; and other attributes, such as standard support for Design for Testability (DFT). Even though this computer system did not complete on time for delivery to the DS1 project, it was an important development along a technology roadmap towards highly integrated and highly miniaturized avionics systems for deep-space applications. This continued technology development is now being performed by NASA's Deep Space System Development Program (also known as X2000) and within JPL's Center for Integrated Space Microsystems (CISM).

  4. Computer Graphics Teaching Support using X3D: Extensible 3D Graphics for Web Authors

    Brutzman, Don

    2008-01-01

    X3D is the ISO-standard scene-graph language for interactive 3D graphics on the Web. A new course is available for teaching the fundamentals of 3D graphics using Extensible 3D (X3D). Resources include a detailed textbook, an authoring tool, hundreds of example scenes, and detailed slidesets covering each chapter. The published book is commercially available, while all other course-module resources are provided online free under open-source licenses. Numerous other commercial and o...

  5. Advanced computational tools for 3-D seismic analysis

    Barhen, J.; Glover, C.W.; Protopopescu, V.A. [Oak Ridge National Lab., TN (United States)] [and others

    1996-06-01

    The global objective of this effort is to develop advanced computational tools for 3-D seismic analysis, and test the products using a model dataset developed under the joint aegis of the United States` Society of Exploration Geophysicists (SEG) and the European Association of Exploration Geophysicists (EAEG). The goal is to enhance the value to the oil industry of the SEG/EAEG modeling project, carried out with US Department of Energy (DOE) funding in FY` 93-95. The primary objective of the ORNL Center for Engineering Systems Advanced Research (CESAR) is to spearhead the computational innovations techniques that would enable a revolutionary advance in 3-D seismic analysis. The CESAR effort is carried out in collaboration with world-class domain experts from leading universities, and in close coordination with other national laboratories and oil industry partners.

  6. Computing Radiative Transfer in a 3D Medium

    Von Allmen, Paul; Lee, Seungwon

    2012-01-01

    A package of software computes the time-dependent propagation of a narrow laser beam in an arbitrary three- dimensional (3D) medium with absorption and scattering, using the transient-discrete-ordinates method and a direct integration method. Unlike prior software that utilizes a Monte Carlo method, this software enables simulation at very small signal-to-noise ratios. The ability to simulate propagation of a narrow laser beam in a 3D medium is an improvement over other discrete-ordinate software. Unlike other direct-integration software, this software is not limited to simulation of propagation of thermal radiation with broad angular spread in three dimensions or of a laser pulse with narrow angular spread in two dimensions. Uses for this software include (1) computing scattering of a pulsed laser beam on a material having given elastic scattering and absorption profiles, and (2) evaluating concepts for laser-based instruments for sensing oceanic turbulence and related measurements of oceanic mixed-layer depths. With suitable augmentation, this software could be used to compute radiative transfer in ultrasound imaging in biological tissues, radiative transfer in the upper Earth crust for oil exploration, and propagation of laser pulses in telecommunication applications.

  7. 3D ultrasound computer tomography: update from a clinical study

    Hopp, T.; Zapf, M.; Kretzek, E.; Henrich, J.; Tukalo, A.; Gemmeke, H.; Kaiser, C.; Knaudt, J.; Ruiter, N. V.

    2016-04-01

    Ultrasound Computer Tomography (USCT) is a promising new imaging method for breast cancer diagnosis. We developed a 3D USCT system and tested it in a pilot study with encouraging results: 3D USCT was able to depict two carcinomas, which were present in contrast enhanced MRI volumes serving as ground truth. To overcome severe differences in the breast shape, an image registration was applied. We analyzed the correlation between average sound speed in the breast and the breast density estimated from segmented MRIs and found a positive correlation with R=0.70. Based on the results of the pilot study we now carry out a successive clinical study with 200 patients. For this we integrated our reconstruction methods and image post-processing into a comprehensive workflow. It includes a dedicated DICOM viewer for interactive assessment of fused USCT images. A new preview mode now allows intuitive and faster patient positioning. We updated the USCT system to decrease the data acquisition time by approximately factor two and to increase the penetration depth of the breast into the USCT aperture by 1 cm. Furthermore the compute-intensive reflectivity reconstruction was considerably accelerated, now allowing a sub-millimeter volume reconstruction in approximately 16 minutes. The updates made it possible to successfully image first patients in our ongoing clinical study.

  8. Computational Modelling of Piston Ring Dynamics in 3D

    Dlugoš Jozef

    2014-12-01

    Full Text Available Advanced computational models of a piston assembly based on the level of virtual prototypes require a detailed description of piston ring behaviour. Considering these requirements, the piston rings operate in regimes that cannot, in general, be simplified into an axisymmetric model. The piston and the cylinder liner do not have a perfect round shape, mainly due to machining tolerances and external thermo-mechanical loads. If the ring cannot follow the liner deformations, a local loss of contact occurs resulting in blow-by and increased consumption of lubricant oil in the engine. Current computational models are unable to implement such effects. The paper focuses on the development of a flexible 3D piston ring model based on the Timoshenko beam theory using the multibody system (MBS. The MBS model is compared to the finite element method (FEM solution.

  9. 3D computer modeling of sitting working place.

    Mijović, B; Ujević, D; Skoko, M; Baksa, S

    2002-12-01

    Ergonomic contribution to designing and modeling of sitting working place by use of a computer and computer programs have been presented in this work. The influences of modeling working places on regular posture of a man/woman during work have been reconsidered, so that consumption of energy and fatigue are brought down to a minimum. For that purpose a computer program has been made which with input data on various kinds of work, sex and height of a worker determines the optimal ergonomic parameters during the modeling of a sitting working place. By computer visualisation the values of angle of spine curving have been calculated, the manipulation angle of arms and legs for three anthropometric heights of workers (160 cm, 175 cm and 190 cm). The dimensions of manipulative body space have been established by computerised 3D anthropometric analysis of movement as for example, reach of arms, legs, head, back etc positions. In this process the dimensions of machine and working space surrounding it in respect to optimal utilisation have been put in accordance with the anthropometric size of a man/woman.

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

    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.

  11. Computed tomographic findings in penetrating peptic ulcer

    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.

  12. Fixture-abutment connection surface and micro-gap measurements by 3D micro-tomographic technique analysis

    Deborah Meleo

    2012-01-01

    Full Text Available X-ray micro-tomography (micro-CT is a miniaturized form of conventional computed axial tomography (CAT able to investigate small radio-opaque objects at a-few-microns high resolution, in a nondestructive, non-invasive, and tri-dimensional way. Compared to traditional optical and electron microscopy techniques, which provide two-dimensional images, this innovative investigation technology enables a sample tri-dimensional analysis without cutting, coating or exposing the object to any particular chemical treatment. X-ray micro-tomography matches ideal 3D microscopy features: the possibility of investigating an object in natural conditions and without any preparation or alteration; non-invasive, non-destructive, and sufficiently magnified 3D reconstruction; reliable measurement of numeric data of the internal structure (morphology, structure and ultra-structure. Hence, this technique has multi-fold applications in a wide range of fields, not only in medical and odontostomatologic areas, but also in biomedical engineering, materials science, biology, electronics, geology, archaeology, oil industry, and semi-conductors industry. This study shows possible applications of micro-CT in dental implantology to analyze 3D micro-features of dental implant to abutment interface. Indeed, implant-abutment misfit is known to increase mechanical stress on connection structures and surrounding bone tissue. This condition may cause not only screw preload loss or screw fracture, but also biological issues in peri-implant tissues.

  13. Computational approaches to 3D modeling of RNA

    Laing, Christian; Schlick, Tamar, E-mail: schlick@nyu.ed [Department of Chemistry and Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, NY 10012 (United States)

    2010-07-21

    Many exciting discoveries have recently revealed the versatility of RNA and its importance in a variety of functions within the cell. Since the structural features of RNA are of major importance to their biological function, there is much interest in predicting RNA structure, either in free form or in interaction with various ligands, including proteins, metabolites and other molecules. In recent years, an increasing number of researchers have developed novel RNA algorithms for predicting RNA secondary and tertiary structures. In this review, we describe current experimental and computational advances and discuss recent ideas that are transforming the traditional view of RNA folding. To evaluate the performance of the most recent RNA 3D folding algorithms, we provide a comparative study in order to test the performance of available 3D structure prediction algorithms for an RNA data set of 43 structures of various lengths and motifs. We find that the algorithms vary widely in terms of prediction quality across different RNA lengths and topologies; most predictions have very large root mean square deviations from the experimental structure. We conclude by outlining some suggestions for future RNA folding research. (topical review)

  14. Computational model of mesenchymal migration in 3D under chemotaxis.

    Ribeiro, F O; Gómez-Benito, M J; Folgado, J; Fernandes, P R; García-Aznar, J M

    2017-01-01

    Cell chemotaxis is an important characteristic of cellular migration, which takes part in crucial aspects of life and development. In this work, we propose a novel in silico model of mesenchymal 3D migration with competing protrusions under a chemotactic gradient. Based on recent experimental observations, we identify three main stages that can regulate mesenchymal chemotaxis: chemosensing, dendritic protrusion dynamics and cell-matrix interactions. Therefore, each of these features is considered as a different module of the main regulatory computational algorithm. The numerical model was particularized for the case of fibroblast chemotaxis under a PDGF-bb gradient. Fibroblasts migration was simulated embedded in two different 3D matrices - collagen and fibrin - and under several PDGF-bb concentrations. Validation of the model results was provided through qualitative and quantitative comparison with in vitro studies. Our numerical predictions of cell trajectories and speeds were within the measured in vitro ranges in both collagen and fibrin matrices. Although in fibrin, the migration speed of fibroblasts is very low, because fibrin is a stiffer and more entangling matrix. Testing PDGF-bb concentrations, we noticed that an increment of this factor produces a speed increment. At 1 ng mL(-1) a speed peak is reached after which the migration speed diminishes again. Moreover, we observed that fibrin exerts a dampening behavior on migration, significantly affecting the migration efficiency.

  15. Glasses for 3D ultrasound computer tomography: phase compensation

    Zapf, M.; Hopp, T.; Ruiter, N. V.

    2016-03-01

    Ultrasound Computer Tomography (USCT), developed at KIT, is a promising new imaging system for breast cancer diagnosis, and was successfully tested in a pilot study. The 3D USCT II prototype consists of several hundreds of ultrasound (US) transducers on a semi-ellipsoidal aperture. Spherical waves are sequentially emitted by individual transducers and received in parallel by many transducers. Reflectivity volumes are reconstructed by synthetic aperture focusing (SAFT). However, straight forward SAFT imaging leads to blurred images due to system imperfections. We present an extension of a previously proposed approach to enhance the images. This approach includes additional a priori information and system characteristics. Now spatial phase compensation was included. The approach was evaluated with a simulation and clinical data sets. An increase in the image quality was observed and quantitatively measured by SNR and other metrics.

  16. Analysis of bite marks in foodstuffs by computer tomography (cone beam CT)--3D reconstruction.

    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. Computer Aided Interpretation Approach for Optical Tomographic Images

    Klose, Christian D; Netz, Uwe; Beuthan, Juergen; Hielscher, Andreas H

    2010-01-01

    A computer-aided interpretation approach is proposed to detect rheumatic arthritis (RA) of human finger joints in optical tomographic images. The image interpretation method employs a multi-variate signal detection analysis aided by a machine learning classification algorithm, called Self-Organizing Mapping (SOM). Unlike in previous studies, this allows for combining multiple physical image parameters, such as minimum and maximum values of the absorption coefficient for identifying affected and not affected joints. Classification performances obtained by the proposed method were evaluated in terms of sensitivity, specificity, Youden index, and mutual information. Different methods (i.e., clinical diagnostics, ultrasound imaging, magnet resonance imaging and inspection of optical tomographic images), were used as "ground truth"-benchmarks to determine the performance of image interpretations. Using data from 100 finger joints, findings suggest that some parameter combinations lead to higher sensitivities while...

  18. Lymphadenopathy in celiac disease: computed tomographic observations

    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.

  19. Computed tomographical evaluation of diabetic nephropathy

    Ubara, Yoshifumi; Hara, Shigeko; Arizono, Kenji; Katori, Hideyuki; Yamada, Akira; Mimura, Nobuhide [Toranomon Hospital, Tokyo (Japan). Kidney Center; Hagura, Ryoko

    1996-06-01

    Diabetic nephropathy can be regarded mainly as a type of microangiopathy, but is a disease that may also include aspects of macroangiopathy. This is especially true of renal disease in non-insulin dependent diabetes mellitus (NIDDM), which is characterized not only by diabetic glomerulosclerosis, but also by atherosclerosis. We performed morphological studies on the kidney, using computed tomography (CT), focusing on such points as: abdominal aortic calcifications at the level of kidney, calcifications in the renal artery, and wedge-shaped defects on the renal surface. We noted that these findings became more prominent in NIDDM patients during end-stage renal failure than during normal renal function, and were significantly more common in those two NIDDM groups than in age-matched nondiabetic patients without hypertension, hyperlipidemia or gout. NIDDM patients exhibited these features more frequently than IDDM patients. (author)

  20. ULTRASOUND AND COMPUTED TOMOGRAPHIC DIAGNOSIS OF OPTIC NERVE TUMORS

    S. V. Saakyan

    2012-01-01

    Full Text Available A comprehensive examination was made in 93 patients, including 18 children, with tumors of the optic nerve (ON. Duplex ultrasound scanning was performed in 39 patients, of them there were 11 patients with ON gliomas and 28 with ON meningiomas. The specific computed tomographic and echographic signs of ON glioma and meningiomas were detected. The studies have shown that duplex ultrasound scanning and structural computed tomography of orbital sockets are highly informative complementary imaging procedures for ON tumors, which permits one to make their correct diagnosis, to specify surgical volume, and to plan adequate treatment.

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

    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.

  2. Computational and methodological developments towards 3D full waveform inversion

    Etienne, V.; Virieux, J.; Hu, G.; Jia, Y.; Operto, S.

    2010-12-01

    Full waveform inversion (FWI) is one of the most promising techniques for seismic imaging. It relies on a formalism taking into account every piece of information contained in the seismic data as opposed to more classical techniques such as travel time tomography. As a result, FWI is a high resolution imaging process able to reach a spatial accuracy equal to half a wavelength. FWI is based on a local optimization scheme and therefore the main limitation concerns the starting model which has to be closed enough to the real one in order to converge to the global minimum. Another counterpart of FWI is the required computational resources when considering models and frequencies of interest. The task becomes even more tremendous when one tends to perform the inversion using the elastic equation instead of using the acoustic approximation. This is the reason why until recently most studies were limited to 2D cases. In the last few years, due to the increase of the available computational power, FWI has focused a lot of interests and continuous efforts towards inversion of 3D models, leading to remarkable applications up to the continental scale. We investigate the computational burden induced by FWI in 3D elastic media and propose some strategic features leading to the reduction of the numerical cost while providing a great flexibility in the inversion parametrization. First, in order to release the memory requirements, we developed our FWI algorithm in the frequency domain and take benefit of the wave-number redundancy in the seismic data to process a quite reduced number of frequencies. To do so, we extract frequency solutions from time marching techniques which are efficient for 3D structures. Moreover, this frequency approach permits a multi-resolution strategy by proceeding from low to high frequencies: the final model at one frequency is used as the starting model for the next frequency. This procedure overcomes partially the non-linear behavior of the inversion

  3. Protein 3D structure computed from evolutionary sequence variation.

    Debora S Marks

    Full Text Available The evolutionary trajectory of a protein through sequence space is constrained by its function. Collections of sequence homologs record the outcomes of millions of evolutionary experiments in which the protein evolves according to these constraints. Deciphering the evolutionary record held in these sequences and exploiting it for predictive and engineering purposes presents a formidable challenge. The potential benefit of solving this challenge is amplified by the advent of inexpensive high-throughput genomic sequencing.In this paper we ask whether we can infer evolutionary constraints from a set of sequence homologs of a protein. The challenge is to distinguish true co-evolution couplings from the noisy set of observed correlations. We address this challenge using a maximum entropy model of the protein sequence, constrained by the statistics of the multiple sequence alignment, to infer residue pair couplings. Surprisingly, we find that the strength of these inferred couplings is an excellent predictor of residue-residue proximity in folded structures. Indeed, the top-scoring residue couplings are sufficiently accurate and well-distributed to define the 3D protein fold with remarkable accuracy.We quantify this observation by computing, from sequence alone, all-atom 3D structures of fifteen test proteins from different fold classes, ranging in size from 50 to 260 residues, including a G-protein coupled receptor. These blinded inferences are de novo, i.e., they do not use homology modeling or sequence-similar fragments from known structures. The co-evolution signals provide sufficient information to determine accurate 3D protein structure to 2.7-4.8 Å C(α-RMSD error relative to the observed structure, over at least two-thirds of the protein (method called EVfold, details at http://EVfold.org. This discovery provides insight into essential interactions constraining protein evolution and will facilitate a comprehensive survey of the universe of

  4. A hybrid method for the computation of quasi-3D seismograms.

    Masson, Yder; Romanowicz, Barbara

    2013-04-01

    The development of powerful computer clusters and efficient numerical computation methods, such as the Spectral Element Method (SEM) made possible the computation of seismic wave propagation in a heterogeneous 3D earth. However, the cost of theses computations is still problematic for global scale tomography that requires hundreds of such simulations. Part of the ongoing research effort is dedicated to the development of faster modeling methods based on the spectral element method. Capdeville et al. (2002) proposed to couple SEM simulations with normal modes calculation (C-SEM). Nissen-Meyer et al. (2007) used 2D SEM simulations to compute 3D seismograms in a 1D earth model. Thanks to these developments, and for the first time, Lekic et al. (2011) developed a 3D global model of the upper mantle using SEM simulations. At the local and continental scale, adjoint tomography that is using a lot of SEM simulation can be implemented on current computers (Tape, Liu et al. 2009). Due to their smaller size, these models offer higher resolution. They provide us with images of the crust and the upper part of the mantle. In an attempt to teleport such local adjoint tomographic inversions into the deep earth, we are developing a hybrid method where SEM computation are limited to a region of interest within the earth. That region can have an arbitrary shape and size. Outside this region, the seismic wavefield is extrapolated to obtain synthetic data at the Earth's surface. A key feature of the method is the use of a time reversal mirror to inject the wavefield induced by distant seismic source into the region of interest (Robertsson and Chapman 2000). We compute synthetic seismograms as follow: Inside the region of interest, we are using regional spectral element software RegSEM to compute wave propagation in 3D. Outside this region, the wavefield is extrapolated to the surface by convolution with the Green's functions from the mirror to the seismic stations. For now, these

  5. 3D Vectorial Time Domain Computational Integrated Photonics

    Kallman, J S; Bond, T C; Koning, J M; Stowell, M L

    2007-02-16

    The design of integrated photonic structures poses considerable challenges. 3D-Time-Domain design tools are fundamental in enabling technologies such as all-optical logic, photonic bandgap sensors, THz imaging, and fast radiation diagnostics. Such technologies are essential to LLNL and WFO sponsors for a broad range of applications: encryption for communications and surveillance sensors (NSA, NAI and IDIV/PAT); high density optical interconnects for high-performance computing (ASCI); high-bandwidth instrumentation for NIF diagnostics; micro-sensor development for weapon miniaturization within the Stockpile Stewardship and DNT programs; and applications within HSO for CBNP detection devices. While there exist a number of photonics simulation tools on the market, they primarily model devices of interest to the communications industry. We saw the need to extend our previous software to match the Laboratory's unique emerging needs. These include modeling novel material effects (such as those of radiation induced carrier concentrations on refractive index) and device configurations (RadTracker bulk optics with radiation induced details, Optical Logic edge emitting lasers with lateral optical inputs). In addition we foresaw significant advantages to expanding our own internal simulation codes: parallel supercomputing could be incorporated from the start, and the simulation source code would be accessible for modification and extension. This work addressed Engineering's Simulation Technology Focus Area, specifically photonics. Problems addressed from the Engineering roadmap of the time included modeling the Auston switch (an important THz source/receiver), modeling Vertical Cavity Surface Emitting Lasers (VCSELs, which had been envisioned as part of fast radiation sensors), and multi-scale modeling of optical systems (for a variety of applications). We proposed to develop novel techniques to numerically solve the 3D multi-scale propagation problem for both the

  6. Weight prediction of broiler chickens using 3D computer vision

    Mortensen, Anders Krogh; Lisouski, Pavel; Ahrendt, Peter

    2016-01-01

    a platform weigher which may also include ill birds. In the current study, a fully-automatic 3D camera-based weighing system for broilers have been developed and evaluated in a commercial production environment. Specifically, a low-cost 3D camera (Kinect) that directly returned a depth image was employed...

  7. Computer-aided teniae coli detection using height maps from computed tomographic colonography images

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

    2011-03-01

    Computed tomographic colonography (CTC) is a minimally invasive technique for colonic polyps and cancer screening. Teniae coli are three bands of longitudinal smooth muscle on the colon surface. They are parallel, equally distributed on the colon wall, and form a triple helix structure from the appendix to the sigmoid colon. Because of their characteristics, teniae coli are important anatomical meaningful landmarks on human colon. This paper proposes a novel method for teniae coli detection on CT colonography. We first unfold the three-dimensional (3D) colon using a reversible projection technique and compute the two-dimensional (2D) height map of the unfolded colon. The height map records the elevation of colon surface relative to the unfolding plane, where haustral folds corresponding to high elevation points and teniae to low elevation points. The teniae coli are detected on the height map and then projected back to the 3D colon. Since teniae are located where the haustral folds meet, we break down the problem by first detecting haustral folds. We apply 2D Gabor filter banks to extract fold features. The maximum response of the filter banks is then selected as the feature image. The fold centers are then identified based on piecewise thresholding on the feature image. Connecting the fold centers yields a path of the folds. Teniae coli are finally extracted as lines running between the fold paths. Experiments were carried out on 7 cases. The proposed method yielded a promising result with an average normalized RMSE of 5.66% and standard deviation of 4.79% of the circumference of the colon.

  8. Computed tomographic features of fibrous dysplasia of maxillofacial region

    Sontakke, Subodh Arun; Karjodka, Freny R [Nair Hospital Dental College, Mumba (India); Umarji, Hemant R [Government Dental College and Hospital, Mumbai (India)

    2011-03-15

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

  9. Design for scalability in 3D computer graphics architectures

    Holten-Lund, Hans Erik

    2002-01-01

    been developed. Hybris is a prototype rendering architeture which can be tailored to many specific 3D graphics applications and implemented in various ways. Parallel software implementations for both single and multi-processor Windows 2000 system have been demonstrated. Working hardware/software...... codesign implementations of Hybris for standard-cell based ASIC (simulated) and FPGA technologies have been demonstrated, using manual co-synthesis for translation of a Virtual Prototyping architecture specification written in C into both optimized C source for software and into to a synthesizable VHDL...... specification for hardware implementation. A flexible VRML 97 3D scene graph engine with a Java interface and C++ interface has been implemented to allow flexible integration of the rendering technology into Java and C++ applications. A 3D medical visualization workstation prototype (3D-Med) is examined...

  10. 3D Printing device adaptable to Computer Numerical Control (CNC)

    Gardan, Julien; DANESI, Frédéric; Roucoules, Lionel; Schneider, A

    2014-01-01

    This article presents the development of a 3D printing device for the additive manufacturing adapted to a CNC machining. The application involves the integration of a specific printing head. Additive manufacturing technology is most commonly used for modeling, prototyping, tooling through an exclusive machine or 3D printer. A global review and analysis of technologies show the additive manufacturing presents little independent solutions [6][9]. The problem studied especially the additive manu...

  11. Inspiratory and expiratory computed tomographic volumetry for lung volume reduction surgery.

    Morimura, Yuki; Chen, Fengshi; Sonobe, Makoto; Date, Hiroshi

    2013-06-01

    Three-dimensional (3D) computed tomographic (CT) volumetry has been introduced into the field of thoracic surgery, and a combination of inspiratory and expiratory 3D-CT volumetry provides useful data on regional pulmonary function as well as the volume of individual lung lobes. We report herein a case of a 62-year-old man with severe emphysema who had undergone lung volume reduction surgery (LVRS) to assess this technique as a tool for the evaluation of regional lung function and volume before and after LVRS. His postoperative pulmonary function was maintained in good condition despite a gradual slight decrease 2 years after LVRS. This trend was also confirmed by a combination of inspiratory and expiratory 3D-CT volumetry. We confirm that a combination of inspiratory and expiratory 3D-CT volumetry might be effective for the preoperative assessment of LVRS in order to determine the amount of lung tissue to be resected as well as for postoperative evaluation. This novel technique could, therefore, be used more widely to assess local lung function.

  12. Computer-aided interpretation approach for optical tomographic images

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

    2010-11-01

    A computer-aided interpretation approach is proposed to detect rheumatic arthritis (RA) in human finger joints using optical tomographic images. The image interpretation method employs a classification algorithm that makes use of a so-called self-organizing mapping scheme to classify fingers as either affected or unaffected by RA. Unlike in previous studies, this allows for combining multiple image features, such as minimum and maximum values of the absorption coefficient for identifying affected and not affected joints. Classification performances obtained by the proposed method were evaluated in terms of sensitivity, specificity, Youden index, and mutual information. Different methods (i.e., clinical diagnostics, ultrasound imaging, magnet resonance imaging, and inspection of optical tomographic images), were used to produce ground truth benchmarks to determine the performance of image interpretations. Using data from 100 finger joints, findings suggest that some parameter combinations lead to higher sensitivities, while others to higher specificities when compared to single parameter classifications employed in previous studies. Maximum performances are reached when combining the minimum/maximum ratio of the absorption coefficient and image variance. In this case, sensitivities and specificities over 0.9 can be achieved. These values are much higher than values obtained when only single parameter classifications were used, where sensitivities and specificities remained well below 0.8.

  13. Software-based geometry operations for 3D computer graphics

    Sima, M.; Iancu, D.; Glossner, J.; Schulte, M.; Mamidi, S.

    2006-01-01

    In order to support a broad dynamic range and a high degree of precision, many of 3D renderings fundamental algorithms have been traditionally performed in floating-point. However, fixed-point data representation is preferable over floatingpoint representation in graphics applications on embedded de

  14. Shadow of a Colossus: A z=2.45 Galaxy Protocluster Detected in 3D Ly-a Forest Tomographic Mapping of the COSMOS Field

    Lee, Khee-Gan; White, Martin; Prochaska, J Xavier; Font-Ribera, Andreu; Schlegel, David J; Rich, R Michael; Suzuki, Nao; Stark, Casey W; Fevre, Olivier Le; Nugent, Peter E; Salvato, Mara; Zamorani, Gianni

    2015-01-01

    Using moderate-resolution optical spectra from 58 background Lyman-break galaxies and quasars at $z\\sim 2.3-3$ within a $11.5'\\times13.5'$ area of the COSMOS field ($\\sim 1200\\,\\mathrm{deg}^2$ projected area density or $\\sim 2.4\\,h^{-1}\\,\\mathrm{Mpc}$ mean transverse separation), we reconstruct a 3D tomographic map of the foreground Ly$\\alpha$ forest absorption at $2.23d}\\approx3.5\\,h^{-1}\\,\\mathrm{Mpc}$ comoving. Comparing with 61 coeval galaxies with spectroscopic redshifts in the same volume, we find that the galaxy positions are clearly biased towards regions with enhanced IGM absorption in the tomographic map. We find an extended IGM overdensity with deep absorption troughs at $z=2.45$ associated with a recently-discovered galaxy protocluster at the same redshift. Based on simulations matched to our data, we estimate the enclosed dark matter mass within this IGM overdensity to be $M_{\\rm dm} (z=2.45) = (9\\pm4)\\times 10^{13}\\,h^{-1}\\,\\mathrm{M_\\o...

  15. Efficient ray tracing on 3D regular grids for fast generation of digitally reconstructed radiographs in iterative tomographic reconstruction techniques

    Dittmann, Jonas

    2016-01-01

    Cone beam projection is an essential and particularly time consuming part of any iterative tomographic reconstruction algorithm. On current graphics hardware especially the amount and pattern of memory accesses is a limiting factor when read-only textures cannot be used. With the final objective of accelerating iterative reconstruction techniques, a non-oversampling Joseph-like raytracing projection algorithm for three dimensions featuring both a branchless sampling loop and a cache friendly memory access pattern is presented. An interpretation of the employed interpolation scheme is given with respect to the effective beam and voxel models implied. The method is further compared to existing techniques, and the modifications required to implement further voxel and beam shape models are outlined. Both memory access rates and total run time are benchmarked on a current consumer grade graphics processing unit and explicitly compared to the performance of a classic Digital Differential Analyzer (DDA) algorithm. T...

  16. Interactive 3D computer model of the human corneolimbal region

    Molvaer, Rikke Kongshaug; Andreasen, Arne; Heegaard, Steffen;

    2013-01-01

    in the superior limbal region and one LEC, six LCs and 12 FSPs in the inferior limbal region. Only few LECs, LCs and FSPs were localized nasally and temporally. CONCLUSION: Interactive 3D models are a powerful tool that may help to shed more light on the existence and spatial localization of the different stem......PURPOSE: This study aims to clarify the existence of and to map the localization of different proposed stem cell niches in the corneal limbal region. MATERIALS AND METHODS: One human eye was cut into 2200 consecutive sections. Every other section was stained with haematoxylin and eosin, digitized...... in the limbal region: limbal epithelial crypts (LECs), limbal crypts (LCs) and focal stromal projections (FSPs). In all, eight LECs, 25 LCs and 105 FSPs were identified in the limbal region. The LECs, LCs and FSPs were predominantly located in the superior limbal region with seven LECs, 19 LCs and 93 FSPs...

  17. 3D computational steering with parametrized geometric objects

    Mulder, J.D.; Wijk, J.J. van

    1996-01-01

    Computational Steering is the ultimate goal of interactive simulation: researchers change parameters of their simulation and immediately receive feedback on the effect. We present a general and flexible graphics tool that is part of an environment for Computational Steering developed at CWI. It enab

  18. Efficient computation of steady, 3D water-wave patterns

    Lewis, M.R.; Koren, B.

    2003-01-01

    Numerical methods for the computation of stationary free surfaces is the subject of much current research in computational engineering. The present report is directed towards free surfaces in maritime engineering. Of interest here are the long steady waves generated by ships, the gravity waves. In t

  19. Computer-assisted three-dimensional surgical planning and simulation: 3D virtual osteotomy.

    Xia, J; Ip, H H; Samman, N; Wang, D; Kot, C S; Yeung, R W; Tideman, H

    2000-02-01

    A computer-assisted three-dimensional virtual osteotomy system for orthognathic surgery (CAVOS) is presented. The virtual reality workbench is used for surgical planning. The surgeon immerses in a virtual reality environment with stereo eyewear, holds a virtual "scalpel" (3D Mouse) and operates on a "real" patient (3D visualization) to obtain pre-surgical prediction (3D bony segment movements). Virtual surgery on a computer-generated 3D head model is simulated and can be visualized from any arbitrary viewing point in a personal computer system.

  20. Exceptionally preserved Cambrian trilobite digestive system revealed in 3D by synchrotron-radiation X-ray tomographic microscopy.

    Mats E Eriksson

    Full Text Available The Cambrian 'Orsten' fauna comprises exceptionally preserved and phosphatised microscopic arthropods. The external morphology of these fossils is well known, but their internal soft-tissue anatomy has remained virtually unknown. Here, we report the first non-biomineralised tissues from a juvenile polymerid trilobite, represented by digestive structures, glands, and connective strands harboured in a hypostome from the Swedish 'Orsten' fauna. Synchrotron-radiation X-ray tomographic microscopy enabled three-dimensional internal recordings at sub-micrometre resolution. The specimen provides the first unambiguous evidence for a J-shaped anterior gut and the presence of a crop with a constricted alimentary tract in the Trilobita. Moreover, the gut is Y-shaped in cross section, probably due to a collapsed lumen of that shape, another feature which has not previously been observed in trilobites. The combination of anatomical features suggests that the trilobite hypostome is functionally analogous to the labrum of euarthropods and that it was a sophisticated element closely integrated with the digestive system. This study also briefly addresses the preservational bias of the 'Orsten' fauna, particularly the near-absence of polymerid trilobites, and the taphonomy of the soft-tissue-harbouring hypostome.

  1. The effect of activity outside the direct field of view in a 3D-only whole-body positron tomograph

    Spinks, T. J.; Miller, M. P.; Bailey, D. L.; Bloomfield, P. M.; Livieratos, L.; Jones, T.

    1998-04-01

    The ECAT EXACT3D (CTI/Siemens 966) 3D-only PET tomograph has unprecedented sensitivity due to the large BGO (bismuth germanate) detector volume. However, the consequences of a large (23.4 cm) axial field-of-view (FOV) and the need for a patient port diameter to accommodate body scanning make the device more sensitive to photons arising from activity outside the direct (coincidence) FOV. This leads to relatively higher deadtime and an increased registration of random and scatter (true) coincidences. The purpose of this study is to determine the influence of activity outside the FOV on (i) noise-equivalent counts (NEC) and (ii) the performance of a `model-based' scatter correction algorithm, and to investigate the effect of side shielding additional to that supplied with the tomograph. Annular shielding designed for brain scanning increased the NEC for blood flow (43/4/017/img1.gif" ALIGN="MIDDLE"/>O) measurement (integrated over 120 s) by up to 25%. For 43/4/017/img2.gif" ALIGN="MIDDLE"/> tracer studies, the increase is less than 5% over 120 min. Purpose-built additional body shielding, made to conform to the shape of a volunteer, reduced the randoms count rate in a heart blood flow measurement (43/4/017/img1.gif" ALIGN="MIDDLE"/>O) by about 30%. After scatter correction the discrepancy between ROI count ratios for compartments within the 20 cm diameter `Utah' phantom differed by less than 5% from true (sampled) activity concentration ratios. This was so with or without activity outside the FOV and with or without additional side shielding. Count rate performance is thus improved by extra shielding but more improvement is seen in head than in body scanning. Measurement of heart blood flow using bolus injections of 43/4/017/img1.gif" ALIGN="MIDDLE"/>O would benefit from the use of detectors with lower deadtime and superior timing resolution such as LSO (lutetium oxyorthosilicate).

  2. The extent of the Cratonic keel underneath the Southern African region: A 3D image using Finite-Frequency Tomograph

    Soliman, Mohammad Youssof Ahmad; Bezada, Max; Thybo, Hans;

    2010-01-01

    We have re-examined the P body wave data from the South Africa Seismic Experiment (Carlson et al, EOS 77, 1996) across the Kaapvaal and Zimbabwe cratons and the Bushveld complex. Using finite-frequency kernels, we inverted the P-wave delay times to obtain 3-D images of compressional velocity...... between the Archean and modified regions such as the Bushveld complex, and the mobile belts surrounding the cratons. The high velocity (+1.0%) cratonic roots extend to 220-250 km depth beneath the Kaapvaal and Zimbabwe cratons. Lower P-velocities are found under the Bushveld complex and the mobile belts...

  3. Current experience with computed tomographic cystography and blunt trauma.

    Deck, A J; Shaves, S; Talner, L; Porter, J R

    2001-12-01

    We present our experience with computed tomographic (CT) cystography for the diagnosis of bladder rupture in patients with blunt abdominal and pelvic trauma and compare the results of CT cystography to operative exploration. We identified all blunt trauma patients diagnosed with bladder rupture from January 1992 to September 1998. We also reviewed the radiology computerized information system (RIS) for all CT cystograms performed for the evaluation of blunt trauma during the same time period. The medical records and pertinent radiographs of the patients with bladder rupture who underwent CT cystography as part of their admission evaluation were reviewed. Operative findings were compared to radiographic findings. Altogether, 316 patients had CT cystograms as part of an initial evaluation for blunt trauma. Of these patients, 44 had an ultimate diagnosis of bladder rupture; 42 patients had CT cystograms indicating bladder rupture. A total of 28 patients underwent formal bladder exploration; 23 (82%) had operative findings that exactly (i.e., presence and type of rupture) matched the CT cystogram interpretation. The overall sensitivity and specificity of CT cystography for detection of bladder rupture were 95% and 100%, respectively. For intraperitoneal rupture, the sensitivity and specificity were 78% and 99%, respectively. CT cystography provides an expedient evaluation for bladder rupture caused by blunt trauma and has an accuracy comparable to that reported for plain film cystography. We recommend CT cystography over plain film cystography for patients undergoing CT evaluation for other blunt trauma-related injuries.

  4. Computed tomographic characteristics of eosinophilic pulmonary granulomatosis in five dogs.

    Fina, Caroline; Vignoli, Massimo; Terragni, Rossella; Rossi, Federica; Wisner, Erik; Saunders, Jimmy H

    2014-01-01

    Canine pulmonary eosinophilic granulomatosis is a rare inflammatory pulmonary disease characterized by formation of eosinophilic granulomas that tend to obliterate the normal pulmonary architecture. The purpose of this retrospective study was to describe the CT characteristics of confirmed idiopathic pulmonary eosinophilic granulomatosis in a group of dogs. Five dogs met inclusion criteria. All patients were young adult dogs of variable breeds. No dog had concurrent occult heartworm disease. Computed tomographic characteristics most commonly included pulmonary masses and nodules of variable size, and lesions were most commonly located in the caudal lung lobes. Four dogs had large pulmonary masses with or without additional nodules and one dog had nodular lesions disseminated throughout the entire lung parenchyma. All large eosinophilic granulomas were smoothly margined, heterogeneous pulmonary masses displaying heterogeneous contrast enhancement. A honeycomb-like enhancement pattern was observed in all but one mass and consisted of multiple hyperattenuating rims delineating central hypoattenuating areas, suggestive of bronchiectatic lung with peripheral enhancing airway walls and fluid-filled, necrotic bronchial lumen. One dog had evidence of tracheobronchial lymphadenopathy. Findings indicated that canine eosinophilic pulmonary granulomatosis should be included as a differential diagnosis for dogs with CT characteristics of multiple pulmonary masses and/or nodules in caudal lung lobes, and a honeycomb-like enhancement pattern in masses after intravenous administration of iodinated contrast medium.

  5. Cerebral computed tomographic angiography scan delay in subarachnoid hemorrhage

    Lukosevicius Saulius

    2005-01-01

    Full Text Available CONTEXT: Computed tomographic angiography (CTA is widely applied in the evaluation of cerebral vessels. Contrast enhancement in cerebral CTA without care or test bolus is not always sufficient for high-quality images. AIMS: Evaluation of the possibilities of calculation of scan delay for cerebral CTA in case of subarachnoid hemorrhage (SAH, based on clinical data of a patient and to find out prognostic error of the model. SETTINGS AND DESIGN: Prospective study in Neurosurgery and Radiology departments. MATERIALS AND METHODS: Scan delay in 53 patients suffering an acute SAH was measured employing test bolus technique. Cerebral CTA was performed afterwards. STATISTICAL ANALYSIS USED: SPSS for Windows v.10.1 software package was applied for dispersion analysis, including one-sample Kolmogorov-Smirnov′s test and Levene′s Test of Equality of Error Variances. RESULTS: A statistical model for the prediction of scan delay in SAH was developed. Cerebral CTA scan delay was dependent upon age, neurological status and impact of the latter factors together (P<0.05. The determined mean square error of prognosis of scan delay of the developed model equals 3.3 sec. CONCLUSION: Using our proposed model it is possible to estimate an optimal delay time for CTA in most patients with SAH with a determined error.

  6. Adoption of Computed Tomographic Colonography by U.S. Hospitals

    McHugh, Megan; Osei-Anto, Awo; Klabunde, Carrie N.; Galen, Barbara A.

    2010-01-01

    Purpose Computed tomographic colonography (CTC) is a new non-invasivetechnology proposed as an option for colorectal cancer screening. The purpose of this study was to identify the percent of U.S. hospitals that offered CTC between 2005 and 2008 and factors that motivated or impeded adoption. Methods We analyzed data on the provision of colorectal cancer screening services by non-federal, general hospitals using the 2005 – 2008 American Hospital Association Annual Surveys. Additionally, in 2009, we conducted exploratory interviews with representatives from radiology departments at nine hospitals – six that provided CTC and three that did not. Results In 2008, 17% of hospitals offered CTC, up from 13% in 2005. Sixty-nine percent of hospitals that offered CTC in 2008 also offered optical colonoscopy services. Factors motivating adoption of CTC included a desire to provide an alternative screening option for frail, elderly patients and patients with a failed optical colonoscopy; long waits for optical colonoscopy; and promising evidence on CTC published in peer-reviewed literature. Lack of reimbursement was a commonly-cited barrier. Conclusion Growth of CTC services at U.S. hospitals occurred even in the absence of Medicare coverage or agreement among national guideline-setting organizations regarding CTC’s use in screening. Almost one-third of hospitals that offer CTC do not offer optical colonoscopy, and may not be prepared to provide adequate follow-up for patients with failed CTCs. PMID:21371666

  7. Study of the Invariants of the Velocity-Gradient Tensor in Homogeneous Isotropic Turbulence by means of 3C-3D Tomographic PIV

    Buchmann, Nicolas; Rouvier, Sylvain; Soria, Julio

    2010-11-01

    The study of coherent structures (CS) in turbulent flows is essential for understanding turbulence mechanisms in technological and theoretical relevant flows. The recent advent of instantaneous three-component and three-dimensional (3C-3D) measurement techniques now permits detailed experimental investigation into the dynamics and topology of CSs by for example analysis of the invariants of the velocity gradient tensor. For this purpose, the present work presents instantaneous, high-resolution 3C-3D Tomographic Particle Image Velocimetry (TPIV) measurements in a grid-generated, homogeneous isotropic turbulent flow (Reλ 140). The experiments are conducted in a larger water tunnel facility using a passive grid, four high-resolution digital cameras and a pulsed Nd:YAG laser for volume illumination. The invariants of the velocity gradient, rate of strain and rate of rotation tensor are used to characterize the dynamics and topology of the turbulent flow field and in particular its dissipation and vortex structure. Preliminary results are in agreement with previous literature and DNS simulations. The objective of this work is to measure these quantities experimentally and directly without additional assumptions pertaining to the structure and dynamics of the turbulent flow field.

  8. Hemodynamic study of hepatocellular car-cinoma nodules by multi-slice spiral computed tomographic perfusion

    马国林

    2013-01-01

    Objective To analyze the 64-slice computed tomographic(CT) perfusion parameters of hepatocellular carcinoma(HCC) nodule so as to assess the diagnostic value of hemodynamic changes of HCC nodule by this perfusion

  9. Building a 3D Computed Tomography Scanner From Surplus Parts.

    Haidekker, Mark A

    2014-01-01

    Computed tomography (CT) scanners are expensive imaging devices, often out of reach for small research groups. Designing and building a CT scanner from modular components is possible, and this article demonstrates that realization of a CT scanner from components is surprisingly easy. However, the high costs of a modular X-ray source and detector limit the overall cost savings. In this article, the possibility of building a CT scanner with available surplus X-ray parts is discussed, and a practical device is described that incurred costs of less than $16,000. The image quality of this device is comparable with commercial devices. The disadvantage is that design constraints imposed by the available components lead to slow scan speeds and a resolution of 0.5 mm. Despite these limitations, a device such as this is attractive for imaging studies in the biological and biomedical sciences, as well as for advancing CT technology itself.

  10. Computed tomographic demonstration of ocular calcification: Correlations with clinical and pathological findings

    Hedges, T.R. III; Pozzi-Mucelli, R.; Char, D.H.; Newton, T.H.

    1982-03-01

    The computed tomographic features of calcification in the eye were correlated with clinical and pathological findings in a variety of ophthalmic and systemic disorders. These consisted of ocular neoplasms, trauma and inflammation of the eye, idiopathic ocular lesions, and disorders of calcium metabolism. Computed tomographic documentation of ocular clarification was found to be useful in the differential diagnosis and management of patients with these disorders.

  11. Probabilistic View-based 3D Curve Skeleton Computation on the GPU

    Kustra, Jacek; Jalba, Andrei; Telea, Alexandru

    2013-01-01

    Computing curve skeletons of 3D shapes is a challenging task. Recently, a high-potential technique for this task was proposed, based on integrating medial information obtained from several 2D projections of a 3D shape. However effective, this technique is strongly influenced in terms of complexity b

  12. CudaPre3D: An Alternative Preprocessing Algorithm for Accelerating 3D Convex Hull Computation on the GPU

    MEI, G.

    2015-05-01

    Full Text Available In the calculating of convex hulls for point sets, a preprocessing procedure that is to filter the input points by discarding non-extreme points is commonly used to improve the computational efficiency. We previously proposed a quite straightforward preprocessing approach for accelerating 2D convex hull computation on the GPU. In this paper, we extend that algorithm to being used in 3D cases. The basic ideas behind these two preprocessing algorithms are similar: first, several groups of extreme points are found according to the original set of input points and several rotated versions of the input set; then, a convex polyhedron is created using the found extreme points; and finally those interior points locating inside the formed convex polyhedron are discarded. Experimental results show that: when employing the proposed preprocessing algorithm, it achieves the speedups of about 4x on average and 5x to 6x in the best cases over the cases where the proposed approach is not used. In addition, more than 95 percent of the input points can be discarded in most experimental tests.

  13. 3D Computational Simulation of Calcium Leaching in Cement Matrices

    Gaitero, J. J.

    2014-12-01

    Full Text Available Calcium leaching is a degradation process consisting in progressive dissolution of the cement paste by migration of calcium atoms to the aggressive solution. It is therefore, a complex phenomenon involving several phases and dissolution and diffusion processes simultaneously. Along this work, a new computational scheme for the simulation of the degradation process in three dimensions was developed and tested. The toolkit was used to simulate accelerated calcium leaching by a 6M ammonium nitrate solution in cement matrices. The obtained outputs were the three dimensional representation of the matrix and the physicochemical properties of individual phases as a consequence of the degradation process. This not only makes it possible to study the evolution of such properties as a function of time but also as a function of the position within the matrix. The obtained results are in good agreement with experimental values of the elastic modulus in degraded and undegraded samples.El lixiviado de calcio es un proceso de degradación consistente en la disolución progresiva de la pasta de cemento por la migración de los átomos de calcio a la disolución agresiva. Se trata por tanto de un fenómeno complejo que involucra simultáneamente diferentes fases y procesos de disolución y difusión. En este trabajo se desarrolló y probó una nueva herramienta computacional para la simulación del proceso de degradación en tres dimensiones. Para ello se simuló el lixiviado de calcio acelerado provocado por una disolución de nitrato amónico 6M en matrices de cemento. Como resultado se obtuvieron la representación tridimensional de la matriz y las propiedades físico-químicas sus fases a lo largo del tiempo. Esto permitió estudiar la evolución de dichas propiedades a lo largo del proceso de degradación así como en función de su posición dentro de la matriz. Los resultados obtenidos coinciden con los valores experimentales del módulo elástico tanto

  14. Combined application of virtual imaging techniques and three-dimensional computed tomographic angiography in diagnosing intracranial aneurysms

    2008-01-01

    Background The diagnostic value of virtual imaging combined with three-dimensional computed tomographic angiography (3D-CTA) for intracranial aneurysms has not been fully elucidated yet. This study aimed to evaluate the value of combined application of virtual imaging techniques and 3D-CTA in diagnosing patients with aneurismal subarachnoid hemorrhage (SAH) at the acute stage. Methods Eighty patients with non-traumatic SAH received 3D-CTA examinations. The raw CT data of these patients were reconstructed and transferred into the 3D mode through the surgical plan system based on virtual reality (VR) image, and the 3D virtual images of skulls and brain blood vessels were acquired. The location, size and shape of aneurysms and their anatomic relationship with adjacent tissues were measured from many points of view. Results Seventy-three aneurysms were detected in 68 of the 80 patients, but 2 aneurysms were detected in 2 of the 5 patients who had been found free of aneurysms previously and had received 3D-CTA examinations for a second time one month later. The 3D virtual images produced by the virtual imaging system were clear and vivid, and they could reveal the location and size of the aneurysm and its relations to the parent artery and skull directly. Conclusions The imaging of 3D-CTA is convenient, reliable and fast in diagnosing intracranial aneurysms and can be regarded as the first choice for the diagnosis and treatment of ruptured intracranial aneurysms. Combined with the surgical plan system based on the VR image, 3D-CTA may obtain more imaging information about aneurysms.

  15. The European-Alpine collision during the last 45Myrs - constraints obtained from comparing 3-D numerical subduction models and tomographic observations

    Morra, G.; Regenauer-Lieb, K.; Kissling, E.; Lippitsch, R.

    2003-04-01

    We analyze the interaction of Adriatic and the European Plates driven self-consistently by slab pull in order to seperate out the roles of (1) intrinsic dynamics of the slab driven Adriatic microplate system, (2) interaction with the subducting European plate, (3) the pushing African plate and (4) the feedback of slab induced flow within the mantle. The simulation is based on a new three-dimensional solid-fluid solver that we developed for plate tectonics reconstruction. The method embeds a Lagrangian Finite Element model of the lithosphere into a creeping medium (Stokeslet Method see poster) representing the mantle. Density inhomogeneities within the subducting plate are inserted to obtain realistic reconstructions of tomographically observed slab lengths in both the Central Mediterranean and European-Alpine subduction systems. In a first step we analyse the system in the absence of the African convergence. With this asssumption the model is only driven by gravity and thus gives an insight into the internal dynamics of the Central-European microplate evolution. In a second step we add the African convergence as a large scale distributed force. Using this method the mechanical origin of rotation of the Adriatic microplate in the vise of the African-European convergence can be analysed and its impact on the collision in the Alps derived. While our solution space is a first set, the aim of the analysis is to obtain constraints of the history of Adriatic-European collision using the new solver as a toolbox. The method has the potential to act as a filter between geological observation, tomographic data and mechanical constraints within the framework of a dynamic 3-D plate tectonic evolution.

  16. Communicating long-span timber structures with 3D computer visualization

    Janols, Henrik

    2005-01-01

    One of the reasons for the low amount of timber in construction is a general lack of knowledge about timber engineering and how timber can be used to its full advantage. In this thesis the focus is 3D computer visualisation (3D VIZ) of non-residential long-span timber structures, used for storage, industry and sports where 3D VIZ is defined as a process where a 3D-model is enhanced with environmental information e.g. texture maps and realistic light effects. An area of interest is the possibi...

  17. Practical limitations of cone-beam computed tomography in 3D cephalometry%Practical limitations of cone-beam computed tomography in3D cephalometry

    Janalt Damstra; Zacharias Fourie; Yijin Ren

    2011-01-01

    3D cone beam computed tomography (CBCT) images offer a unique and new appreciation of the anatomical structures and underlying anomalies not possible with conventional radiographs.However,in almost all aspects of CBCT imaging,from utilization to application,inherent limitations and pitfalls exist.Importantly,these inherent limitations and pitfalls have practical implications which need to be addressed before the potential of this technology can be fully realized.The purpose of this review was to explore the current limitations and pitfalls associated with CBCT imaging to allow for better and more accurate understanding of the possibilities this imaging modality could offer,particularly pertaining to 3D cephalometry.

  18. Anaplastic Thyroid Carcinoma: Computed Tomographic Differentiation from Other Thyroid Masses

    Lee, Jun Won; Yoon, Dae Young; Choi, Chul Soon; Chang, Suk Ki; Yun, Eun Joo; Seo, Young Lan; Rho, Young-Soo; Jin Cho, Sung; Kim, Keon Ha (Depts. of Radiology, Otorhinolaryngology, and Pathology, Kangdong Seong-Sim Hospital, Hallym Univ. College of Medicine, Seoul (KR))

    2008-04-15

    Background: Anaplastic thyroid carcinoma is rare but is one of the most aggressive malignancies. Therefore, accurate diagnosis is important in order to provide appropriate therapy. Purpose: To establish useful computed tomographic (CT) criteria for differentiating anaplastic carcinoma from other thyroid masses. Material and Methods: The CT scans of nine patients with anaplastic carcinomas were retrospectively reviewed and compared with those of 32 patients with papillary carcinomas (n = 12) or benign lesions (n = 20) exceeding a maximum diameter of 2.0 cm. Image analysis was performed according to the following CT parameters: size, margin (well defined or ill defined), composition (cystic, mixed, or solid), mean attenuation value, ratio of attenuation of the mass to that of the adjacent muscle (M/m attenuation ratio), necrosis (present or absent), and calcification (stippled, nodular, or absent) of the thyroid mass; and tumor-spreading patterns including the presence of surrounding normal thyroid tissue in the involved lobe, involvement of the contralateral thyroid lobe, extension into the adjacent structures, and cervical lymphadenopathy. Results: Anaplastic carcinomas appeared as large (average 4.6 cm), solid (100%), and ill-defined (88.9%) masses accompanied by necrosis (100%), nodular calcification (44.4%), direct invasion into the adjacent organs (55.6%), and cervical lymph node involvement (77.8%). Tumor necrosis was the most valuable parameter in differentiating anaplastic carcinomas from other thyroid masses. Patient age (>70 years) and low attenuation value on postcontrast scan (attenuation value <100 HU, or M/m attenuation ratio <1.3) are also helpful predictors for anaplastic carcinoma. Conclusion: If a patient is older than 70 years of age and has a large necrotic thyroid mass of low attenuation, anaplastic carcinoma should be included in the differential diagnosis

  19. Predictors of incomplete optical colonoscopy using computed tomographic colonography

    Reetika Sachdeva

    2016-01-01

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

  20. Computed tomographic features of lymphangioleiomyomatosis: Evaluation in 138 patients

    Tobino, Kazunori, E-mail: tobino@juntendo.ac.jp [Department of Respiratory Medicine, Iizuka Hospital, 3-83 Yoshiomachi, Iizuka, Fukuoka 820-0018 (Japan); Division of Respiratory Medicine, Juntendo University Faculty of Medicine & Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo 113-8421 (Japan); The Study Group of Pneumothorax and Cystic Lung Diseases, 4-8-1 Seta, Setagaya-Ku, Tokyo 158-0095 (Japan); Johkoh, Takeshi [Department of Radiology, Kinki Central Hospital of Mutual Aid Association of Public School Teachers, Kurumazuka 3-1, Itami, Hyogo 664-0872 (Japan); Fujimoto, Kiminori [Department of Radiology, Kurume University School of Medicine and Center for Diagnostic Imaging, Kurume University Hospital, 67 Asahi-machi, Kurume, Fukuoka 830-0011 (Japan); Sakai, Fumikazu [Department of Diagnostic Radiology, Saitama International Medical Center, Saitama Medical University, 1397-1 Yamane, Hidaka, Saitama 350-1298 (Japan); Arakawa, Hiroaki [Department of Radiology, Dokkyo Medical University, 880 Kita-Kobayashi, Mibu, Tochigi 321-0293 (Japan); Kurihara, Masatoshi [The Study Group of Pneumothorax and Cystic Lung Diseases, 4-8-1 Seta, Setagaya-Ku, Tokyo 158-0095 (Japan); Pneumothorax Center, Nissan Tamagawa Hospital, 4-8-1 Seta, Setagaya-Ku, Tokyo 158-0095 (Japan); Kumasaka, Toshio [The Study Group of Pneumothorax and Cystic Lung Diseases, 4-8-1 Seta, Setagaya-Ku, Tokyo 158-0095 (Japan); Department of Pathology, Japanese Red Cross Medical Center, 4-1-22 Hiroo, Shibuya-Ku, Tokyo 150-0012 (Japan); Koike, Kengo; Takahashi, Kazuhisa [Division of Respiratory Medicine, Juntendo University Faculty of Medicine & Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo 113-8421 (Japan); Seyama, Kuniaki [Division of Respiratory Medicine, Juntendo University Faculty of Medicine & Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo 113-8421 (Japan); The Study Group of Pneumothorax and Cystic Lung Diseases, 4-8-1 Seta, Setagaya-Ku, Tokyo 158-0095 (Japan)

    2015-03-15

    Highlights: •In our series, the frequency of pulmonary nodules was higher than in the previous reports. •Our sporadic LAM patients had a lower frequency of renal AML than in that of previous reports. •LAM patients may have a high incidence of renal and hepatic cysts. •LAM cells may originate in the pelvis then spread via the axial lymphatic system. -- Abstract: Purpose: The aim was to characterize the computed tomographic (CT) findings from Japanese patients with lymphangioleiomyomatosis (LAM). Materials and methods: CT scans of the chest, abdomen, and pelvis from 124 patients with sporadic LAM (S-LAM, mean age, 37.4 years) and 14 patients with tuberous sclerosis complex (TSC)-LAM (mean age, 35.6 years) were analyzed. Results: Pulmonary nodules (18.8%) and hepatic angiomyolipoma (AML, 24.3%) were more common in our patients than those in previous reports. Compared with TSC-LAM, S-LAM group had a higher frequency of pulmonary nodules (28.6% vs 32.3%, P < 0.01) and lower frequencies of air-space consolidation (21.4% vs 2.4%, P < 0.01), pneumothorax (28.6% vs 8.1%, P = 0.02), pulmonary hilar lymphadenopathy (14.3% vs 0.8%, P < 0.01), renal AML (85.7% vs 17.4%, P < 0.01), hepatic AML (71.4% vs 17.4%, P < 0.01), and retrocrural lymphadenopathy (14.3% vs 1.4%, P = 0.04). Axial lymphatic abnormalities (i.e., thoracic duct dilatation, lymphadenopathy, and lymphangioleiomyoma) were most common in the pelvis and tended to decrease in incidence with increased distance from the pelvis. Conclusion: The incidence of some CT findings in Japanese patients differed from those in previous reports. Axial lymphatic abnormalities noted here suggest that the origin of LAM cells may be the pelvis.

  1. Three-dimensional multislice spiral computed tomographic angiography: a potentially useful tool for safer free tissue transfer to complicated regions

    Demirtas, Yener; Cifci, Mehmet; Kelahmetoglu, Osman;

    2009-01-01

    Three-dimensional multislice spiral computed tomographic angiography (3D-MSCTA) is a minimally invasive method of vascular mapping. The aim of this study was to evaluate the clinical usefulness of this imaging technique in delineating the recipient vessels for safer free tissue transfer...... to complicated regions. 3D-MSCTA was performed preoperatively in 26 patients scheduled for free tissue transfer, in whom the availability of the recipient vessels were considered to be uncertain, and 23 of these were operated on. Radiographic and operative findings regarding the availability of the recipient......-MSCTA provides a noninvasive means of preoperatively assessing recipient site vessels for anatomic variations and suitability before free tissue transfer and enables the surgeon to establish an appropriate treatment plan. But it is not 100% reliable yet and the possibility of false-positive results should...

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

    Jose-Ignacio Agulleiro

    2015-06-01

    Full Text Available 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.

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

    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.

  4. Effect of coordinate rotation on 3D molecular descriptors computed by DragonX

    Hechinger, Manuel

    2012-01-01

    Quantitative structure-property relations (QSPR) employing descriptors derived from the 3D molecular structure are frequently applied for property prediction in various fields of research. In particular, DragonX is one of the most widely used software packages for descriptor calculation. The reliability of 3D molecular descriptors computed by DragonX has lately been investigated, thereby focusing on the effect of computational methods used for molecular structure optimization on the accuracy of the resulting molecular descriptors. The present contribution extends the analysis to a more intrinsic problem of DragonX descriptor evaluation resulting from the sensitivity of the computed 3D descriptors on the coordinate system used for molecule description. Evaluating several 3D descriptors for converged molecular structures rotated around all 3 spatial axes (affine coordinate transformations) yields systematically varying descriptor values. Since this unphysical behavior severely affects the descriptor reliability...

  5. An Approach to Computer Modeling of Geological Faults in 3D and an Application

    ZHU Liang-feng; HE Zheng; PAN Xin; WU Xin-cai

    2006-01-01

    3D geological modeling, one of the most important applications in geosciences of 3D GIS, forms the basis and is a prerequisite for visualized representation and analysis of 3D geological data. Computer modeling of geological faults in 3D is currently a topical research area. Structural modeling techniques of complex geological entities containing reverse faults are discussed and a series of approaches are proposed. The geological concepts involved in computer modeling and visualization of geological fault in 3D are explained, the type of data of geological faults based on geological exploration is analyzed, and a normative database format for geological faults is designed. Two kinds of modeling approaches for faults are compared: a modeling technique of faults based on stratum recovery and a modeling technique of faults based on interpolation in subareas. A novel approach, called the Unified Modeling Technique for stratum and fault, is presented to solve the puzzling problems of reverse faults, syn-sedimentary faults and faults terminated within geological models. A case study of a fault model of bed rock in the Beijing Olympic Green District is presented in order to show the practical result of this method. The principle and the process of computer modeling of geological faults in 3D are discussed and a series of applied technical proposals established. It strengthens our profound comprehension of geological phenomena and the modeling approach, and establishes the basic techniques of 3D geological modeling for practical applications in the field of geosciences.

  6. Electro-holography display using computer generated hologram of 3D objects based on projection spectra

    Huang, Sujuan; Wang, Duocheng; He, Chao

    2012-11-01

    A new method of synthesizing computer-generated hologram of three-dimensional (3D) objects is proposed from their projection images. A series of projection images of 3D objects are recorded with one-dimensional azimuth scanning. According to the principles of paraboloid of revolution in 3D Fourier space and 3D central slice theorem, spectra information of 3D objects can be gathered from their projection images. Considering quantization error of horizontal and vertical directions, the spectrum information from each projection image is efficiently extracted in double circle and four circles shape, to enhance the utilization of projection spectra. Then spectra information of 3D objects from all projection images is encoded into computer-generated hologram based on Fourier transform using conjugate-symmetric extension. The hologram includes 3D information of objects. Experimental results for numerical reconstruction of the CGH at different distance validate the proposed methods and show its good performance. Electro-holographic reconstruction can be realized by using an electronic addressing reflective liquid-crystal display (LCD) spatial light modulator. The CGH from the computer is loaded onto the LCD. By illuminating a reference light from a laser source to the LCD, the amplitude and phase information included in the CGH will be reconstructed due to the diffraction of the light modulated by the LCD.

  7. Clinical outcomes following spinal fusion using an intraoperative computed tomographic 3D imaging system.

    Xiao, Roy; Miller, Jacob A; Sabharwal, Navin C; Lubelski, Daniel; Alentado, Vincent J; Healy, Andrew T; Mroz, Thomas E; Benzel, Edward C

    2017-03-03

    OBJECTIVE Improvements in imaging technology have steadily advanced surgical approaches. Within the field of spine surgery, assistance from the O-arm Multidimensional Surgical Imaging System has been established to yield superior accuracy of pedicle screw insertion compared with freehand and fluoroscopic approaches. Despite this evidence, no studies have investigated the clinical relevance associated with increased accuracy. Accordingly, the objective of this study was to investigate the clinical outcomes following thoracolumbar spinal fusion associated with O-arm-assisted navigation. The authors hypothesized that increased accuracy achieved with O-arm-assisted navigation decreases the rate of reoperation secondary to reduced hardware failure and screw misplacement. METHODS A consecutive retrospective review of all patients who underwent open thoracolumbar spinal fusion at a single tertiary-care institution between December 2012 and December 2014 was conducted. Outcomes assessed included operative time, length of hospital stay, and rates of readmission and reoperation. Mixed-effects Cox proportional hazards modeling, with surgeon as a random effect, was used to investigate the association between O-arm-assisted navigation and postoperative outcomes. RESULTS Among 1208 procedures, 614 were performed with O-arm-assisted navigation, 356 using freehand techniques, and 238 using fluoroscopic guidance. The most common indication for surgery was spondylolisthesis (56.2%), and most patients underwent a posterolateral fusion only (59.4%). Although O-arm procedures involved more vertebral levels compared with the combined freehand/fluoroscopy cohort (4.79 vs 4.26 vertebral levels; p fusion only (HR 0.39; p fusion (HR 0.22; p = 0.03), but not posterior/transforaminal lumbar interbody fusion. CONCLUSIONS To the authors' knowledge, the present study is the first to investigate clinical outcomes associated with O-arm-assisted navigation following thoracolumbar spinal fusion. O-arm-assisted navigation decreased the risk of reoperation to less than half the risk associated with freehand and fluoroscopic approaches. Future randomized controlled trials to corroborate the findings of the present study are warranted.

  8. 3D computed tomographic evaluation of secondary alveolar bone grafts in cleft lip and palate patients

    Ohkubo, Fumio; Akai, Hidemi; Hosaka, Yoshiaki [Showa Univ., Tokyo (Japan). School of Medicine

    2001-04-01

    Alveolar bone grafting in patients with cleft lip and palate has becomes a routine part of most treatment regimes. This study was undertaken to estimate how much bone needs to be grafted into the cleft cavity and to evaluate the grafted bone using 3-DCT over a period from the early postoperative stage to after one year. Seventy-five patients divided into four groups according to the type of cleft were studied. All patients underwent secondary alveolar bone grafting using particulate cancellous bone from the anterior iliac crest. The bone graft areas were divided into two regions: the extra-cleft region and the intra-cleft region. The weight and the volume of the grafted bone were correlated and the average density was 1.5 g/ml regardless of the cleft type. The bone in the extra-cleft region could be seen in almost all slices of the CT scans, from the lower alveolar process to the piriform aperture. The extra-cleft graft ratio of unilateral and bilateral cleft lip and palate is higher than that of cleft lip and alveolus. The extra-cleft grafting is necessary to restore facial symmetry. The grafted bone was decreased in both height and volume following three months and adequate bone bridging was maintained for one year. We concluded that 3-DCT findings are one of the most valuable methods to evaluate postoperative conditions after alveolar bone grafting. (author)

  9. Assembly of a 3D Cellular Computer Using Folded E-Blocks

    Shivendra Pandey

    2016-04-01

    Full Text Available The assembly of integrated circuits in three dimensions (3D provides a possible solution to address the ever-increasing demands of modern day electronic devices. It has been suggested that by using the third dimension, devices with high density, defect tolerance, short interconnects and small overall form factors could be created. However, apart from pseudo 3D architecture, such as monolithic integration, die, or wafer stacking, the creation of paradigms to integrate electronic low-complexity cellular building blocks in architecture that has tile space in all three dimensions has remained elusive. Here, we present software and hardware foundations for a truly 3D cellular computational devices that could be realized in practice. The computing architecture relies on the scalable, self-configurable and defect-tolerant cell matrix. The hardware is based on a scalable and manufacturable approach for 3D assembly using folded polyhedral electronic blocks (E-blocks. We created monomers, dimers and 2 × 2 × 2 assemblies of polyhedral E-blocks and verified the computational capabilities by implementing simple logic functions. We further show that 63.2% more compact 3D circuits can be obtained with our design automation tools compared to a 2D architecture. Our results provide a proof-of-concept for a scalable and manufacture-ready process for constructing massive-scale 3D computational devices.

  10. Computer-Designed Splints for Surgical Transfer of 3D Orthognathic Planning.

    Zinser, Max; Zoeller, Joachim

    2015-10-01

    Advances in computers and imaging have permitted the adoption of three-dimensional (3D) planning protocols in orthognathic surgery, which may allow a paradigm shift when the computer-assisted planning can be transferred properly. The purpose of this investigation was to introduce an innovative clinical protocol using computer-aided designed and computer-aided manufactured (CAD/CAM) surgical splints for surgical transfer of 3D orthognathic planning compared with the classic technique using arbitrary occlusal splints. The clinical protocols consisted of computed tomography (CT) or cone-beam CT (CBCT) maxillofacial imaging, bone segmentation, 3D diagnosis, computer-assisted surgical treatment planning, and CAD/CAM surgical splints (group A) and manufacture of arbitrary occlusal splints (group B) for intraoperative surgical planning transfer. The observed patients underwent bimaxillary osteotomies and, if necessary, an additional genioplasty. Both techniques were evaluated by applying 13 hard tissue parameters to compare the 3D orthognathic planning (T0) with the postoperative result (T1) using 3D cephalometry. The CAD/CAM splints showed significant better precision for the maxilla (ΔT orthognathic planning, which is more precise compared with the conventional arbitrary occlusal splints.

  11. Time- and Computation-Efficient Calibration of MEMS 3D Accelerometers and Gyroscopes

    Sara Stančin

    2014-08-01

    Full Text Available We propose calibration methods for microelectromechanical system (MEMS 3D accelerometers and gyroscopes that are efficient in terms of time and computational complexity. The calibration process for both sensors is simple, does not require additional expensive equipment, and can be performed in the field before or between motion measurements. The methods rely on a small number of defined calibration measurements that are used to obtain the values of 12 calibration parameters. This process enables the static compensation of sensor inaccuracies. The values detected by the 3D sensor are interpreted using a generalized 3D sensor model. The model assumes that the values detected by the sensor are equal to the projections of the measured value on the sensor sensitivity axes. Although this finding is trivial for 3D accelerometers, its validity for 3D gyroscopes is not immediately apparent; thus, this paper elaborates on this latter topic. For an example sensor device, calibration parameters were established using calibration measurements of approximately 1.5 min in duration for the 3D accelerometer and 2.5 min in duration for the 3D gyroscope. Correction of each detected 3D value using the established calibration parameters in further measurements requires only nine addition and nine multiplication operations.

  12. Time- and computation-efficient calibration of MEMS 3D accelerometers and gyroscopes.

    Stančin, Sara; Tomažič, Sašo

    2014-08-13

    We propose calibration methods for microelectromechanical system (MEMS) 3D accelerometers and gyroscopes that are efficient in terms of time and computational complexity. The calibration process for both sensors is simple, does not require additional expensive equipment, and can be performed in the field before or between motion measurements. The methods rely on a small number of defined calibration measurements that are used to obtain the values of 12 calibration parameters. This process enables the static compensation of sensor inaccuracies. The values detected by the 3D sensor are interpreted using a generalized 3D sensor model. The model assumes that the values detected by the sensor are equal to the projections of the measured value on the sensor sensitivity axes. Although this finding is trivial for 3D accelerometers, its validity for 3D gyroscopes is not immediately apparent; thus, this paper elaborates on this latter topic. For an example sensor device, calibration parameters were established using calibration measurements of approximately 1.5 min in duration for the 3D accelerometer and 2.5 min in duration for the 3D gyroscope. Correction of each detected 3D value using the established calibration parameters in further measurements requires only nine addition and nine multiplication operations.

  13. Extended gray level co-occurrence matrix computation for 3D image volume

    Salih, Nurulazirah M.; Dewi, Dyah Ekashanti Octorina

    2017-02-01

    Gray Level Co-occurrence Matrix (GLCM) is one of the main techniques for texture analysis that has been widely used in many applications. Conventional GLCMs usually focus on two-dimensional (2D) image texture analysis only. However, a three-dimensional (3D) image volume requires specific texture analysis computation. In this paper, an extended 2D to 3D GLCM approach based on the concept of multiple 2D plane positions and pixel orientation directions in the 3D environment is proposed. The algorithm was implemented by breaking down the 3D image volume into 2D slices based on five different plane positions (coordinate axes and oblique axes) resulting in 13 independent directions, then calculating the GLCMs. The resulted GLCMs were averaged to obtain normalized values, then the 3D texture features were calculated. A preliminary examination was performed on a 3D image volume (64 x 64 x 64 voxels). Our analysis confirmed that the proposed technique is capable of extracting the 3D texture features from the extended GLCMs approach. It is a simple and comprehensive technique that can contribute to the 3D image analysis.

  14. 3D computer-assisted assessment of complicated penetrating foreign bodies cases in ENT practice.

    Vaiman, Michael; Bekerman, Inessa; Puterman, Max

    2009-10-01

    A retrospective research was performed in order to evaluate three-dimensional (3D) computer-assisted detection of penetrating foreign bodies (FB) in the ENT practice in order to assess its usefulness and to specify its application. FBs in the head and neck were detected using 3D CT imaging in order to assess the usefulness of 3D images in the ENT operative practice. Three blinded surgeons were involved in comparison between plain and 3D CT images in order to assess 3D usefulness for precise formulation of a surgical plan. The observed relationship of the FBs to anatomical structures of the ethmoidal sinuses, eye orbit, and neck tissues was found instrumental for surgeon's decision making in planning the approach to operative removal of the FB. It helps to understand the relationships between a FB and surrounding anatomical structures better then the plain X-rays or CT-scan. There was no significant difference in cost between plain CT and 3D images. 3D computer-assisted detection of FBs increase our diagnostic abilities and appears to be a valuable addition to our diagnostic technique. Its main importance, however, lies in its capacity to help a surgeon plan an operation much more carefully avoiding improvisation during the operation itself.

  15. Ground truth evaluation of computer vision based 3D reconstruction of synthesized and real plant images

    Nielsen, Michael; Andersen, Hans Jørgen; Slaughter, David

    2007-01-01

    There is an increasing interest in using 3D computer vision in precision agriculture. This calls for better quantitative evaluation and understanding of computer vision methods. This paper proposes a test framework using ray traced crop scenes that allows in-depth analysis of algorithm performance...

  16. Quantitative analysis of periapical lesions on cone beam computed tomograph and periapical radiograph

    Kim, Jin Hoa; Lee, Wan; Kim, Kyung Soo; Roh, Young Chea; Lee, Byung Do [Department of Oral and Maxillofacial Radiology, School of Dentistry, Wonkwang University, Iksan (Korea, Republic of); Kim, De Sok [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology, Deajeon (Korea, Republic of)

    2009-03-15

    To detect the progression of experimentally induced periapical lesions on periapical radiograph and cone beam computed tomograph (CBCT) by quantitative analysis. After the removal of coronal pulps from premolars of two Beagle dogs, the root canals of premolars were exposed to oral environment during one week and then sealed for 70 days. Digital periapical radiographs and CBCTs were taken at baseline and every 7 days for 77 days after pulp exposure. We examined occurrence and areas of periapical bone resorption. Three comparative groups of CBCT radiographs were prepared by average projection of thin slabs with different bucco-lingual thicknesses (0.1, 3.0, and 8.0 mm) using a 3D visualization software. Radiographic densities were compensated by image normalization. Digital images were processed with mathematical morphology operations. The radiographic density and morphological features of periapical lesions were compared among three groups of CBCT in different time points. In the CBCT group with 0.1 mm thickness, radiographic density (p<0.05) and trabecular bone area (p<0.01) were significantly decreased at the fifth week. However, in the CBCT groups with 3 mm and 8 mm thickness and periapical radiographs, none of densitometric and morphological features showed any significant differences in different time points. Radiographic density of periapical lesion showed increasing tendency at the eleventh week after pulp exposure. Radiographic detection of periapical lesions was possible at the fifth week after pulp contamination by quantitative method and was affected by buccolingual bone thickness.

  17. 3D COMPUTER SIMULATION FOR LIGNIFICATION OF ANCIENT CHINESE TIMBER BUILDINGS

    2001-01-01

    A pioneer research work was carried out by investigators engaged in surveying and mapping for describing ancient Chinese timber buildings by 3D frame graphs w ith a computer.Users can know the structural layers and the assembly process of the se buildings if the frame graphs are processed further with a computer model.Th is can be implemented by computer simulation technique.This technique display t he raw data on the screen of a computer and interactively manage them by combini ng technologies from computer graphics and image processing,multi-media technol ogy,artificial intelligence,highly parallel real-time computation technique an d human behavior science.This paper presents the implementing procedure of ligni fi cation simulation for large-sized wooden buildings as well as 3D dynamic assembl y of these buildings under the 3DS MAX environment.The results from computer sim ulation are also shown in the paper.

  18. 3D-SoftChip: A Novel Architecture for Next-Generation Adaptive Computing Systems

    Lee Mike Myung-Ok

    2006-01-01

    Full Text Available This paper introduces a novel architecture for next-generation adaptive computing systems, which we term 3D-SoftChip. The 3D-SoftChip is a 3-dimensional (3D vertically integrated adaptive computing system combining state-of-the-art processing and 3D interconnection technology. It comprises the vertical integration of two chips (a configurable array processor and an intelligent configurable switch through an indium bump interconnection array (IBIA. The configurable array processor (CAP is an array of heterogeneous processing elements (PEs, while the intelligent configurable switch (ICS comprises a switch block, 32-bit dedicated RISC processor for control, on-chip program/data memory, data frame buffer, along with a direct memory access (DMA controller. This paper introduces the novel 3D-SoftChip architecture for real-time communication and multimedia signal processing as a next-generation computing system. The paper further describes the advanced HW/SW codesign and verification methodology, including high-level system modeling of the 3D-SoftChip using SystemC, being used to determine the optimum hardware specification in the early design stage.

  19. Evaluation of contrast-enhanced computed tomographic colonography in detection of local recurrent colorectal cancer

    Yau-Tong You; Chung-Rong Chang Chien; Jeng-Yi Wang; Koon-Kwan Ng; Jinn-Shiun Chen; Reiping Tang; Jy-Ming Chiang; Chien-Yuh Yeh; Pao-Shiu Hsieh

    2006-01-01

    AIM: To evaluate the diagnostic accuracy, sensitivity,specificity of contrast-enhanced computed tomographic colonography in detecting local recurrence of colorectal cancer.METHODS: From January 2000 to December 2004,434 patients after potentially curative resection for invasive colorectal cancer were followed up for a period ranging from 20 to 55 mo. Eighty of the four hundred and thirty-four patients showing strong clinical evidence for recurring colorectal cancer during the last followup were enrolled in this study. Each patient underwent contrast-enhanced computed tomographic colonography and colonoscopy on the same day. Any lesions, biopsies,identified during the colonoscopic examination, immediate complications and the duration of the procedure were recorded. The results of contrast-enhanced computed tomographic colonography were evaluated by comparing to those of colonoscopy, surgical finding, and clinical follow-up.RESULTS: Contrast-enhanced computed tomographic colonography had a sensitivity of 100%, a specificity of 83% and an overall accuracy of 94% in detecting local recurrent colorectal cancer.CONCLUSION: Conventional colonoscopy and contrastenhanced tomographic colonography can complement each other in detecting local recurrence of colorectal cancer.

  20. Spiral computed tomographic imaging related to computerized ultrasonographic images of carotid plaque morphology and histology

    Grønholdt, Marie-Louise; Wagner, A; Wiebe, B M;

    2001-01-01

    Echolucency of carotid atherosclerotic plaques, as evaluated by computerized B-mode ultrasonographic images, has been associated with an increased incidence of brain infarcts on cerebral computed tomographic scans. We tested the hypotheses that characterization of carotid plaques on spiral comput...

  1. Compilation of a recent seismicity data base of the greater Alpine region from several seismological networks and preliminary 3D tomographic results

    M. Granet

    1997-06-01

    Full Text Available Local earthquake data collected by seven national and regional seismic networks have been compiled into a travel time catalog of 32341 earthquakes for the period 1980 to 1995 in South-Central Europe. As a prerequisite, a complete and corrected station list (master station list has been prepared according to updated information provided by every network. By simultaneous inversion of some 600 well-locatable events we obtained one-dimensional (1D velocity propagation models for each network. Consequently, these velocity models with appropriate station corrections have been used to obtain high-quality hypocenter locations for events inside and among the station networks. For better control, merging of phase data from several networks was performed as an iterative process where at each iteration two data sets of neighbouring networks or groups of networks were merged. Particular care was taken to detect and correctly identify phase data from events common to data sets from two different networks. In case of reports of the same phase data from more than one network, the phase data from the network owning and servicing the station were used according to the master station list. The merging yielded a data set of 278007 P and 191074 S-wave travel time observations from 32341 events in the greater Alpine region. Restrictive selection (number of P-wave observations >7; gap <160 degrees yielded a data set of about 10000 events with a total of more than 128000 P and 87000 S-wave observations well suited for local earthquake seismic tomography study. Preliminary tomographic results for South-Central Europe clearly show the topography of the crust-mantle boundary in the greater Alpine region and outline the 3D structure of the seismic Ivrea body.

  2. Meta!Blast computer game: a pipeline from science to 3D art to education

    Schneller, William; Campbell, P. J.; Bassham, Diane; Wurtele, Eve Syrkin

    2012-03-01

    Meta!Blast (http://www.metablast.org) is designed to address the challenges students often encounter in understanding cell and metabolic biology. Developed by faculty and students in biology, biochemistry, computer science, game design, pedagogy, art and story, Meta!Blast is being created using Maya (http://usa.autodesk.com/maya/) and the Unity 3D (http://unity3d.com/) game engine, for Macs and PCs in classrooms; it has also been exhibited in an immersive environment. Here, we describe the pipeline from protein structural data and holographic information to art to the threedimensional (3D) environment to the game engine, by which we provide a publicly-available interactive 3D cellular world that mimics a photosynthetic plant cell.

  3. Using swath bathymetry as an a priori constraint in a 3D full wavefield tomographic inversion of seismic data across oceanic crust

    Morgan, J. V.; Christeson, G. L.; Warner, M.

    2009-12-01

    structure in the upper crust and across the 2A/2B boundary. However, the sea-bed is topographically rough and individual shot gathers occasionally contain more than one sea-bed reflection, and it is not clear which reflections are from directly below the seismic profile and which are offline. Hence, we are concerned that these offline sea-bed reflections may be incorrectly mapped into 2D velocity structure in the upper oceanic crust. To address this, we use 3D swath bathymetry data as an a priori constraint in a newly-developed 3D full wavefield code. First, we forward model the sea-bed reflection using the 3D bathymetry, for a suite of 2D seismic profiles that are spaced 500 m apart. We use these data to distinguish between the online and offline sea-bed reflections, and we explore the effects of keeping the sea-bed fixed in our 2D inversions. Our results will be used to guide a 3D full wavefield tomographic inversion of these data.

  4. [Hardware-software system for monitoring parameters and characteristics of X-ray computer tomographs under operation conditions].

    Blinov, N N; Zelikman, M I; Kruchinin, S A

    2007-01-01

    The results of testing of hardware and software for monitoring parameters (mean number of CT units, noise, field uniformity, high-contrast spatial resolution, layer width, dose) and characteristics (modulation transfer function) of X-ray computer tomographs are presented. The developed hardware and software are used to monitor the stability of X-ray computer tomograph parameters under operation conditions.

  5. Temporal bone anomalies in the branchio-oto-renal syndrome: detailed computed tomographic and magnetic resonance imaging findings.

    Ceruti, S.; Stinckens, C.I.C.; Cremers, C.W.R.J.; Casselman, J.W.

    2002-01-01

    OBJECTIVE: To inventory computed tomographic and magnetic resonance imaging findings in the branchio-oto-renal (BOR) syndrome. STUDY DESIGN: A prospective computed tomographic and magnetic resonance imaging study on a family with the BOR syndrome. SETTING: Department of medical imaging and magnetic

  6. Novel fully integrated computer system for custom footwear: from 3D digitization to manufacturing

    Houle, Pascal-Simon; Beaulieu, Eric; Liu, Zhaoheng

    1998-03-01

    This paper presents a recently developed custom footwear system, which integrates 3D digitization technology, range image fusion techniques, a 3D graphical environment for corrective actions, parametric curved surface representation and computer numerical control (CNC) machining. In this system, a support designed with the help of biomechanics experts can stabilize the foot in a correct and neutral position. The foot surface is then captured by a 3D camera using active ranging techniques. A software using a library of documented foot pathologies suggests corrective actions on the orthosis. Three kinds of deformations can be achieved. The first method uses previously scanned pad surfaces by our 3D scanner, which can be easily mapped onto the foot surface to locally modify the surface shape. The second kind of deformation is construction of B-Spline surfaces by manipulating control points and modifying knot vectors in a 3D graphical environment to build desired deformation. The last one is a manual electronic 3D pen, which may be of different shapes and sizes, and has an adjustable 'pressure' information. All applied deformations should respect a G1 surface continuity, which ensure that the surface can accustom a foot. Once the surface modification process is completed, the resulting data is sent to manufacturing software for CNC machining.

  7. Optimisation of coronary vascular territorial 3D echocardiographic strain imaging using computed tomography

    de Knegt, Martina Chantal; Fuchs, A; Weeke, P;

    2016-01-01

    Current echocardiographic assessments of coronary vascular territories use the 17-segment model and are based on general assumptions of coronary vascular distribution. Fusion of 3D echocardiography (3DE) with multidetector computed tomography (MDCT) derived coronary anatomy may provide a more acc...

  8. Practical limitations of cone-beam computed tomography in 3D cephalometry

    Damstra, Janalt; Fourie, Zacharias; Ren, Yijin

    2011-01-01

    3D cone beam computed tomography (CBCT) images offer a unique and new appreciation of the anatomical structures and underlying anomalies not possible with conventional radiographs. However, in almost all aspects of CBCT imaging, from utilization to application, inherent limitations and pitfalls exis

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

    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.

  10. Organ printing: computer-aided jet-based 3D tissue engineering.

    Mironov, Vladimir; Boland, Thomas; Trusk, Thomas; Forgacs, Gabor; Markwald, Roger R

    2003-04-01

    Tissue engineering technology promises to solve the organ transplantation crisis. However, assembly of vascularized 3D soft organs remains a big challenge. Organ printing, which we define as computer-aided, jet-based 3D tissue-engineering of living human organs, offers a possible solution. Organ printing involves three sequential steps: pre-processing or development of "blueprints" for organs; processing or actual organ printing; and postprocessing or organ conditioning and accelerated organ maturation. A cell printer that can print gels, single cells and cell aggregates has been developed. Layer-by-layer sequentially placed and solidified thin layers of a thermo-reversible gel could serve as "printing paper". Combination of an engineering approach with the developmental biology concept of embryonic tissue fluidity enables the creation of a new rapid prototyping 3D organ printing technology, which will dramatically accelerate and optimize tissue and organ assembly.

  11. Analysis of 3-D images of dental imprints using computer vision

    Aubin, Michele; Cote, Jean; Laurendeau, Denis; Poussart, Denis

    1992-05-01

    This paper addressed two important aspects of dental analysis: (1) location and (2) identification of the types of teeth by means of 3-D image acquisition and segmentation. The 3-D images of both maxillaries are acquired using a wax wafer as support. The interstices between teeth are detected by non-linear filtering of the 3-D and grey-level data. Two operators are presented: one for the detection of the interstices between incisors, canines, and premolars and one for those between molars. Teeth are then identified by mapping the imprint under analysis on the computer model of an 'ideal' imprint. For the mapping to be valid, a set of three reference points is detected on the imprint. Then, the points are put in correspondence with similar points on the model. Two such points are chosen based on a least-squares fit of a second-order polynomial of the 3-D data in the area of canines. This area is of particular interest since the canines show a very characteristic shape and are easily detected on the imprint. The mapping technique is described in detail in the paper as well as pre-processing of the 3-D profiles. Experimental results are presented for different imprints.

  12. A Computer Vision Method for 3D Reconstruction of Curves-Marked Free-Form Surfaces

    Xiong Hanwei; Zhang Xiangwei

    2001-01-01

    Visual method is now broadly used in reverse engineering for 3D reconstruction. Thetraditional computer vision methods are feature-based, i.e., they require that the objects must revealfeatures owing to geometry or textures. For textureless free-form surfaces, dense feature points areadded artificially. In this paper, a new method is put forward combining computer vision with CAGD.The surface is subdivided into N-side Gregory patches using marked curves, and a stereo algorithm isused to reconstruct the curves. Then, the cross boundary tangent vector is computed throughreflectance analysis. At last, the whole surface can be reconstructed by jointing these patches withG1 continuity.

  13. The computer simulation of 3d gas dynamics in a gas centrifuge

    Borman, V. D.; Bogovalov, S. V.; Borisevich, V. D.; Tronin, I. V.; Tronin, V. N.

    2016-09-01

    We argue on the basis of the results of 2D analysis of the gas flow in gas centrifuges that a reliable calculation of the circulation of the gas and gas content in the gas centrifuge is possible only in frameworks of 3D numerical simulation of gas dynamics in the gas centrifuge (hereafter GC). The group from National research nuclear university, MEPhI, has created a computer code for 3D simulation of the gas flow in GC. The results of the computer simulations of the gas flows in GC are presented. A model Iguassu centrifuge is explored for the simulations. A nonaxisymmetric gas flow is produced due to interaction of the hypersonic rotating flow with the scoops for extraction of the product and waste flows from the GC. The scoops produce shock waves penetrating into a working camera of the GC and form spiral waves there.

  14. Gust Acoustics Computation with a Space-Time CE/SE Parallel 3D Solver

    Wang, X. Y.; Himansu, A.; Chang, S. C.; Jorgenson, P. C. E.; Reddy, D. R. (Technical Monitor)

    2002-01-01

    The benchmark Problem 2 in Category 3 of the Third Computational Aero-Acoustics (CAA) Workshop is solved using the space-time conservation element and solution element (CE/SE) method. This problem concerns the unsteady response of an isolated finite-span swept flat-plate airfoil bounded by two parallel walls to an incident gust. The acoustic field generated by the interaction of the gust with the flat-plate airfoil is computed by solving the 3D (three-dimensional) Euler equations in the time domain using a parallel version of a 3D CE/SE solver. The effect of the gust orientation on the far-field directivity is studied. Numerical solutions are presented and compared with analytical solutions, showing a reasonable agreement.

  15. Sand transverse dune aerodynamics: 3D Coherent Flow Structures from a computational study

    Bruno, Luca

    2015-01-01

    The engineering interest about dune fields is dictated by the their interaction with a number of human infrastructures in arid environments. The aerodynamic behaviour of sand dunes in atmospheric boundary layer belongs to the class of bluff bodies. Because of their simple geometry and their frequent occurrence in desert area, transverse sand dunes are usually adopted in literature as a benchmark to investigate dune aerodynamics by means of both computational or experimental approach, usually in nominally 2D setups. The writers suspect the flow in the wake is characterised by 3D features and affected by wind tunnel setup - e.g. blockage effect, duct side wall boundary layer, incoming velocity profile - when experimental studies are carried out. The present study aims at evaluating the 3D flow features of an idealised transverse dune under different setup conditions by means of computational simulations and to compare the obtained results with experimental measurements.

  16. Confocal 3D DNA Cytometry: Assessment of Required Coefficient of Variation by Computer Simulation

    Lennert S. Ploeger

    2004-01-01

    Full Text Available Background: Confocal Laser Scanning Microscopy (CLSM provides the opportunity to perform 3D DNA content measurements on intact cells in thick histological sections. So far, sample size has been limited by the time consuming nature of the technology. Since the power of DNA histograms to resolve different stemlines depends on both the sample size and the coefficient of variation (CV of histogram peaks, interpretation of 3D CLSM DNA histograms might be hampered by both a small sample size and a large CV. The aim of this study was to analyze the required CV for 3D CLSM DNA histograms given a realistic sample size. Methods: By computer simulation, virtual histograms were composed for sample sizes of 20000, 10000, 5000, 1000, and 273 cells and CVs of 30, 25, 20, 15, 10 and 5%. By visual inspection, the histogram quality with respect to resolution of G0/1 and G2/M peaks of a diploid stemline was assessed. Results: As expected, the interpretability of DNA histograms deteriorated with decreasing sample sizes and higher CVs. For CVs of 15% and lower, a clearly bimodal peak pattern with well distinguishable G0/1 and G2/M peaks were still seen at a sample size of 273 cells, which is our current average sample size with 3D CLSM DNA cytometry. Conclusions: For unambiguous interpretation of DNA histograms obtained using 3D CLSM, a CV of at most 15% is tolerable at currently achievable sample sizes. To resolve smaller near diploid stemlines, a CV of 10% or better should be aimed at. With currently available 3D imaging technology, this CV is achievable.

  17. Integration of 3D anatomical data obtained by CT imaging and 3D optical scanning for computer aided implant surgery

    Paoli Alessandro

    2011-02-01

    Full Text Available Abstract Background A precise placement of dental implants is a crucial step to optimize both prosthetic aspects and functional constraints. In this context, the use of virtual guiding systems has been recognized as a fundamental tool to control the ideal implant position. In particular, complex periodontal surgeries can be performed using preoperative planning based on CT data. The critical point of the procedure relies on the lack of accuracy in transferring CT planning information to surgical field through custom-made stereo-lithographic surgical guides. Methods In this work, a novel methodology is proposed for monitoring loss of accuracy in transferring CT dental information into periodontal surgical field. The methodology is based on integrating 3D data of anatomical (impression and cast and preoperative (radiographic template models, obtained by both CT and optical scanning processes. Results A clinical case, relative to a fully edentulous jaw patient, has been used as test case to assess the accuracy of the various steps concurring in manufacturing surgical guides. In particular, a surgical guide has been designed to place implants in the bone structure of the patient. The analysis of the results has allowed the clinician to monitor all the errors, which have been occurring step by step manufacturing the physical templates. Conclusions The use of an optical scanner, which has a higher resolution and accuracy than CT scanning, has demonstrated to be a valid support to control the precision of the various physical models adopted and to point out possible error sources. A case study regarding a fully edentulous patient has confirmed the feasibility of the proposed methodology.

  18. RF-TSV DESIGN, MODELING AND APPLICATION FOR 3D MULTI-CORE COMPUTER SYSTEMS

    Yu Le; Yang Haigang; Xie Yuanlu

    2012-01-01

    The state-of-the-art multi-core computer systems are based on Very Large Scale three Dimensional (3D) Integrated circuits (VLSI).In order to provide high-speed vertical data transmission in such 3D systems,efficient Through-Silicon Via (TSV) technology is critically important.In this paper,various Radio Frequency (RF) TSV designs and models are proposed.Specifically,the Cu-plug TSV with surrounding ground TSVs is used as the baseline structure.For further improvement,the dielectric coaxial and novel air-gap coaxial TSVs are introduced.Using the empirical parameters of these coaxial TSVs,the simulation results are obtained demonstrating that these coaxial RF-TSVs can provide two-order higher of cut-off frequencies than the Cu-plug TSVs.Based on these new RF-TSV technologies,we propose a novel 3D multi-core computer system as well as new architectures for manipulating the interfaces between RF and baseband circuit.Taking into consideration the scaling down of IC manufacture technologies,predictions for the performance of future generations of circuits are made.With simulation results indicating energy per bit and area per bit being reduced by 7% and 11% respectively,we can conclude that the proposed method is a worthwhile guideline for the design of future multi-core computer ICs.

  19. A 3D learning playground for potential attention training in ADHD: A brain computer interface approach.

    Ali, Abdulla; Puthusserypady, Sadasivan

    2015-01-01

    This paper presents a novel brain-computer-interface (BCI) system that could potentially be used for enhancing the attention ability of subjects with attention deficit hyperactivity disorder (ADHD). It employs the steady state visual evoked potential (SSVEP) paradigm. The developed system consists of a 3D classroom environment with active 3D distractions and 2D games executed on the blackboard. The system is concealed as a game (with stages of varying difficulty) with an underlying story to motivate the subjects. It was tested on eleven healthy subjects and the results undeniably establish that by moving to a higher stage in the game where the 2D environment is changed to 3D along with the added 3D distractions, the difficulty level in keeping attention on the main task increases for the subjects. Results also show a mean accuracy of 92.26 ± 7.97% and a mean average selection time of 3.07 ± 1.09 seconds.

  20. Computer-aided planning and reconstruction of cranial 3D implants.

    Gall, Markus; Xing Li; Xiaojun Chen; Schmalstieg, Dieter; Egger, Jan

    2016-08-01

    In this contribution, a prototype for semiautomatic computer-aided planning and reconstruction of cranial 3D Implants is presented. The software prototype guides the user through the workflow, beginning with loading and mirroring the patient's head to obtain an initial curvature of the cranial implant. However, naïve mirroring is not sufficient for an implant, because human heads are in general too asymmetric. Thus, the user can perform Laplacian smoothing, followed by Delaunay triangulation, for generating an aesthetic looking and well-fitting implant. Finally, our software prototype allows to save the designed 3D model of the implant as a STL-file for 3D printing. The 3D printed implant can be used for further pre-interventional planning or even as the final implant for the patient. In summary, our findings show that a customized MeVisLab prototype can be an alternative to complex commercial planning software, which may not be available in a clinic.

  1. 3D animation of facial plastic surgery based on computer graphics

    Zhang, Zonghua; Zhao, Yan

    2013-12-01

    More and more people, especial women, are getting desired to be more beautiful than ever. To some extent, it becomes true because the plastic surgery of face was capable in the early 20th and even earlier as doctors just dealing with war injures of face. However, the effect of post-operation is not always satisfying since no animation could be seen by the patients beforehand. In this paper, by combining plastic surgery of face and computer graphics, a novel method of simulated appearance of post-operation will be given to demonstrate the modified face from different viewpoints. The 3D human face data are obtained by using 3D fringe pattern imaging systems and CT imaging systems and then converted into STL (STereo Lithography) file format. STL file is made up of small 3D triangular primitives. The triangular mesh can be reconstructed by using hash function. Top triangular meshes in depth out of numbers of triangles must be picked up by ray-casting technique. Mesh deformation is based on the front triangular mesh in the process of simulation, which deforms interest area instead of control points. Experiments on face model show that the proposed 3D animation facial plastic surgery can effectively demonstrate the simulated appearance of post-operation.

  2. 3D fast adaptive correlation imaging for large-scale gravity data based on GPU computation

    Chen, Z.; Meng, X.; Guo, L.; Liu, G.

    2011-12-01

    In recent years, large scale gravity data sets have been collected and employed to enhance gravity problem-solving abilities of tectonics studies in China. Aiming at the large scale data and the requirement of rapid interpretation, previous authors have carried out a lot of work, including the fast gradient module inversion and Euler deconvolution depth inversion ,3-D physical property inversion using stochastic subspaces and equivalent storage, fast inversion using wavelet transforms and a logarithmic barrier method. So it can be say that 3-D gravity inversion has been greatly improved in the last decade. Many authors added many different kinds of priori information and constraints to deal with nonuniqueness using models composed of a large number of contiguous cells of unknown property and obtained good results. However, due to long computation time, instability and other shortcomings, 3-D physical property inversion has not been widely applied to large-scale data yet. In order to achieve 3-D interpretation with high efficiency and precision for geological and ore bodies and obtain their subsurface distribution, there is an urgent need to find a fast and efficient inversion method for large scale gravity data. As an entirely new geophysical inversion method, 3D correlation has a rapid development thanks to the advantage of requiring no a priori information and demanding small amount of computer memory. This method was proposed to image the distribution of equivalent excess masses of anomalous geological bodies with high resolution both longitudinally and transversely. In order to tranform the equivalence excess masses into real density contrasts, we adopt the adaptive correlation imaging for gravity data. After each 3D correlation imaging, we change the equivalence into density contrasts according to the linear relationship, and then carry out forward gravity calculation for each rectangle cells. Next, we compare the forward gravity data with real data, and

  3. THERM3D -- A boundary element computer program for transient heat conduction problems

    Ingber, M.S. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Mechanical Engineering

    1994-02-01

    The computer code THERM3D implements the direct boundary element method (BEM) to solve transient heat conduction problems in arbitrary three-dimensional domains. This particular implementation of the BEM avoids performing time-consuming domain integrations by approximating a ``generalized forcing function`` in the interior of the domain with the use of radial basis functions. An approximate particular solution is then constructed, and the original problem is transformed into a sequence of Laplace problems. The code is capable of handling a large variety of boundary conditions including isothermal, specified flux, convection, radiation, and combined convection and radiation conditions. The computer code is benchmarked by comparisons with analytic and finite element results.

  4. Automatic procedure for realistic 3D finite element modelling of human brain for bioelectromagnetic computations

    Aristovich, K Y; Khan, S H, E-mail: kirill.aristovich.1@city.ac.u [School of Engineering and Mathematical Sciences, City University London, Northampton Square, London EC1V 0HB (United Kingdom)

    2010-07-01

    Realistic computer modelling of biological objects requires building of very accurate and realistic computer models based on geometric and material data, type, and accuracy of numerical analyses. This paper presents some of the automatic tools and algorithms that were used to build accurate and realistic 3D finite element (FE) model of whole-brain. These models were used to solve the forward problem in magnetic field tomography (MFT) based on Magnetoencephalography (MEG). The forward problem involves modelling and computation of magnetic fields produced by human brain during cognitive processing. The geometric parameters of the model were obtained from accurate Magnetic Resonance Imaging (MRI) data and the material properties - from those obtained from Diffusion Tensor MRI (DTMRI). The 3D FE models of the brain built using this approach has been shown to be very accurate in terms of both geometric and material properties. The model is stored on the computer in Computer-Aided Parametrical Design (CAD) format. This allows the model to be used in a wide a range of methods of analysis, such as finite element method (FEM), Boundary Element Method (BEM), Monte-Carlo Simulations, etc. The generic model building approach presented here could be used for accurate and realistic modelling of human brain and many other biological objects.

  5. 3D histomorphometric quantification of trabecular bones by computed microtomography using synchrotron radiation.

    Nogueira, L P; Braz, D; Barroso, R C; Oliveira, L F; Pinheiro, C J G; Dreossi, D; Tromba, G

    2010-12-01

    Conventional bone histomorphometry is an important method for quantitative evaluation of bone microstructure. X-ray computed microtomography is a non-invasive technique, which can be used to evaluate histomorphometric indices in trabecular bones (BV/TV, BS/BV, Tb.N, Tb.Th, Tb.Sp). In this technique, 3D images are used to quantify the whole sample, differently from the conventional one, in which the quantification is performed in 2D slices and extrapolated for 3D case. In this work, histomorphometric quantification using synchrotron 3D X-ray computed microtomography was performed to quantify the bone structure at different skeletal sites as well as to investigate the effects of bone diseases on quantitative understanding of bone architecture. The images were obtained at Synchrotron Radiation for MEdical Physics (SYRMEP) beamline, at ELETTRA synchrotron radiation facility, Italy. Concerning the obtained results for normal and pathological bones from same skeletal sites and individuals, from our results, a certain declining bone volume fraction was achieved. The results obtained could be used in forming the basis for comparison of the bone microarchitecture and can be a valuable tool for predicting bone fragility.

  6. Vacuum facet phenomenon: a computed tomographic sign of degenerative spondylolisthesis

    Lefkowitz, D.M.; Quencer, D.M.

    1982-08-01

    A vacuum facet phenomenon, seen on computed tomography as a lens-shaped lucency within a lumbar facet joint, was observed as a consequence of degenerative spondylolisthesis. The significance of this finding is discussed.

  7. Computation of Edge-Edge-Edge Events Based on Conicoid Theory for 3-D Object Recognition

    WU Chenye; MA Huimin

    2009-01-01

    The availability of a good viewpoint space partition is crucial in three dimensional (3-D) object rec-ognition on the approach of aspect graph. There are two important events depicted by the aspect graph ap-proach, edge-edge-edge (EEE) events and edge-vertex (EV) events. This paper presents an algorithm to compute EEE events by characteristic analysis based on conicoid theory, in contrast to current algorithms that focus too much on EV events and often overlook the importance of EEE events. Also, the paper provides a standard flowchart for the viewpoint space partitioning based on aspect graph theory that makes it suitable for perspective models. The partitioning result best demonstrates the algorithm's efficiency with more valu-able viewpoints found with the help of EEE events, which can definitely help to achieve high recognition rate for 3-D object recognition.

  8. The current status of the development of the technology on 3D computer simulation in Japan

    Kim, Hee Reyoung; Park, Seung Kook; Chung, Un Soo; Jung, Ki Jung

    2002-05-01

    The development background and property of the COSIDA, which is the 3D computer simulation system for the analysis on the dismantling procedure of the nuclear facilities in Japan was reviewed. The function of the visualization on the work area, Kinematics analysis and dismantling scenario analysis, which are the sub systems of the COSIDA, has been investigated. The physical, geometrical and radiological properties were modelled in 2D or 3D in the sub system of the visualization of the work area. In the sub system of the kinematics analysis, the command set on the basic work procedure for the control of the motion of the models at a cyber space was driven. The suitability of the command set was estimated by the application of COSIDA to the programming on the motion of the remote dismantling tools for dismantling the components of the nuclear facilities at cyber space.

  9. Computational fluid dynamics simulations of blood flow regularized by 3D phase contrast MRI

    Rispoli, Vinicius C; Nielsen, Jon; Nayak, Krishna S

    2015-01-01

    approach in regularizing 3D flow fields is evaluated. METHODS: The proposed algorithm incorporates both a Newtonian fluid physics model and a linear PC-MRI signal model. The model equations are solved numerically using a modified CFD algorithm. The numerical solution corresponds to the optimal solution......BACKGROUND: Phase contrast magnetic resonance imaging (PC-MRI) is used clinically for quantitative assessment of cardiovascular flow and function, as it is capable of providing directly-measured 3D velocity maps. Alternatively, vascular flow can be estimated from model-based computation fluid...... dynamics (CFD) calculations. CFD provides arbitrarily high resolution, but its accuracy hinges on model assumptions, while velocity fields measured with PC-MRI generally do not satisfy the equations of fluid dynamics, provide limited resolution, and suffer from partial volume effects. The purpose...

  10. Computer-assisted three-dimensional surgical planning: 3D virtual articulator: technical note.

    Ghanai, S; Marmulla, R; Wiechnik, J; Mühling, J; Kotrikova, B

    2010-01-01

    This study presents a computer-assisted planning system for dysgnathia treatment. It describes the process of information gathering using a virtual articulator and how the splints are constructed for orthognathic surgery. The deviation of the virtually planned splints is shown in six cases on the basis of conventionally planned cases. In all cases the plaster models were prepared and scanned using a 3D laser scanner. Successive lateral and posterior-anterior cephalometric images were used for reconstruction before surgery. By identifying specific points on the X-rays and marking them on the virtual models, it was possible to enhance the 2D images to create a realistic 3D environment and to perform virtual repositioning of the jaw. A hexapod was used to transfer the virtual planning to the real splints. Preliminary results showed that conventional repositioning could be replicated using the virtual articulator.

  11. Dynamic enhanced computed tomographic findings of a perirenal capillary hemangioma

    Lee, Jung Min; Kim, Sang Won; Kim, Hyun Cheol; Yang, Dal Mo; Ryu, Jung Kyu; Lim, Sung Jig [Kyung Hee University Hospital at Gangdong, Seoul (Korea, Republic of)

    2016-05-15

    Hemangiomas are benign mesenchymal neoplasms that rarely occur in the kidney and perirenal space. Perirenal hemangiomas can mimic the appearance of exophytic renal cell carcinoma or various retroperitoneal tumors. We report a case of perirenal hemangioma detected by dynamic enhanced computed tomography in a 43-year-old female.

  12. Subperiosteal hematomas of the orbit: angiographic and computed tomographic diagnosis

    Seigel, R.S. (Univ. of New Mexico, Albuquerque); Williams, A.G.; Hutchison, J.W.; Wolter, J.R.; Carlow, T.J.; Rogers, D.E.

    1982-06-01

    Subperiosteal hematomas of the orbit are a rare complication of blunt head trauma that may on occasion occur spontaneously. Angiography and computed tomography (CT) were used in the diagnosis of three cases of subperiosteal hematoma. In the proper clinical setting, orbital CT can give a precise delineation of the size and extent of this hematoma.

  13. Computational Analysis of the Transonic Dynamics Tunnel Using FUN3D

    Chwalowski, Pawel; Quon, Eliot; Brynildsen, Scott E.

    2016-01-04

    This paper presents results from an explanatory two-year effort of applying Computational Fluid Dynamics (CFD) to analyze the empty-tunnel flow in the NASA Langley Research Center Transonic Dynamics Tunnel (TDT). The TDT is a continuous-flow, closed circuit, 16- x 16-foot slotted-test-section wind tunnel, with capabilities to use air or heavy gas as a working fluid. In this study, experimental data acquired in the empty tunnel using the R-134a test medium was used to calibrate the computational data. The experimental calibration data includes wall pressures, boundary-layer profiles, and the tunnel centerline Mach number profiles. Subsonic and supersonic flow regimes were considered, focusing on Mach 0.5, 0.7 and Mach 1.1 in the TDT test section. This study discusses the computational domain, boundary conditions, and initial conditions selected in the resulting steady-state analyses using NASA's FUN3D CFD software.

  14. Using 2D and 3D Computer Games to Detect Colorblindness – a Comparative Study

    Laskowski Maciej

    2015-12-01

    Full Text Available Computer games have accompanied the development of computer technologies since the very beginning. Despite their basic, purely entertainment-targeted appliance, games can also be used for many other purposes. Medical applications are especially interesting, as games (especially different kinds of simulations are widely used for training personnel, e.g. to perform certain procedures or in learning to use equipment. This allows the trainees to gain knowledge and proper habits, as well as test themselves in different situations without any risk. Computer games can also be used as a diagnostic tool, although this topic is still insufficiently researched. This paper discusses the possibility of using serious games for diagnosing color vision disorders, focusing especially on two problems: differences in diagnosing colorblindness using 2D and 3D environments, and the influence of individual features, such as reflex or agility, on the diagnostic process.

  15. Generic camera model and its calibration for computational integral imaging and 3D reconstruction.

    Li, Weiming; Li, Youfu

    2011-03-01

    Integral imaging (II) is an important 3D imaging technology. To reconstruct 3D information of the viewed objects, modeling and calibrating the optical pickup process of II are necessary. This work focuses on the modeling and calibration of an II system consisting of a lenslet array, an imaging lens, and a charge-coupled device camera. Most existing work on such systems assumes a pinhole array model (PAM). In this work, we explore a generic camera model that accommodates more generality. This model is an empirical model based on measurements, and we constructed a setup for its calibration. Experimental results show a significant difference between the generic camera model and the PAM. Images of planar patterns and 3D objects were computationally reconstructed with the generic camera model. Compared with the images reconstructed using the PAM, the images present higher fidelity and preserve more high spatial frequency components. To the best of our knowledge, this is the first attempt in applying a generic camera model to an II system.

  16. The history of visual magic in computers how beautiful images are made in CAD, 3D, VR and AR

    Peddie, Jon

    2013-01-01

    If you have ever looked at a fantastic adventure or science fiction movie, or an amazingly complex and rich computer game, or a TV commercial where cars or gas pumps or biscuits behaved liked people and wondered, ""How do they do that?"",  then you've experienced the magic of 3D worlds generated by a computer.3D in computers began as a way to represent automotive designs and illustrate the construction of molecules. 3D graphics use evolved to visualizations of simulated data and artistic representations of imaginary worlds. In order to overcome the processing limitations of the computer, graph

  17. Computed tomographic diagnosis of nongastrointestinal foreign bodies in dogs.

    Jones, Jeryl C; Ober, Christopher P

    2007-01-01

    Clinical data and computed tomography (CT) studies were reviewed for 13 dogs with confirmed nongastrointestinal foreign bodies. Locations of foreign bodies were the nasal cavity, thoracic wall, retropharyngeal region, and cerebellum. Types of foreign bodies included small plant components, blades of grass, wooden sticks, cloth fibers, and a needle. Foreign bodies in five dogs were not identified on CT, and secondary reactions resembled neoplastic or fungal disease. In eight dogs, foreign bodies were recognized by their shape and/or internal architecture. In two dogs, three-dimensional reformatting helped demonstrate foreign bodies in relation to palpable bony landmarks.

  18. Chronic septic arthritis of the adult hip: Computed tomographic features

    Resnik, C.S.; Ammann, A.M.; Walsh, J.W.

    1987-10-01

    Abnormalities on computed tomography (CT) are described in 12 adults in whom septic arthritis of the hip was diagnosed. Presenting symptoms varied, as did CT findings. Soft tissue abnormalities ranged from intra-articular effusion to large abscess formation, and bone changes ranged from minimal erosion of articular surfaces to gross destruction of the proximal femur and acetabulum. CT can be helpful in the evaluation of septic arthritis of the hip because of its superior demonstration of soft tissue detail. An accurate diagnosis can be established in unsuspected cases and can be confirmed when clinical indicators are vague.

  19. An approximate 3D computational method for real-time computation of induction logging responses

    Bensdorp, S.; Petersen, S.A.; Van den Berg, P.M.; Fokkema, J.T.

    2014-01-01

    Over many years, induction logging systems have been used to create well formation logs. The major drawback for the utilization of these tools is the long simulation time for a single forward computation. We proposed an efficient computational method based on a contrast-type of integral-equation for

  20. 3D virtual human atria: A computational platform for studying clinical atrial fibrillation.

    Aslanidi, Oleg V; Colman, Michael A; Stott, Jonathan; Dobrzynski, Halina; Boyett, Mark R; Holden, Arun V; Zhang, Henggui

    2011-10-01

    Despite a vast amount of experimental and clinical data on the underlying ionic, cellular and tissue substrates, the mechanisms of common atrial arrhythmias (such as atrial fibrillation, AF) arising from the functional interactions at the whole atria level remain unclear. Computational modelling provides a quantitative framework for integrating such multi-scale data and understanding the arrhythmogenic behaviour that emerges from the collective spatio-temporal dynamics in all parts of the heart. In this study, we have developed a multi-scale hierarchy of biophysically detailed computational models for the human atria--the 3D virtual human atria. Primarily, diffusion tensor MRI reconstruction of the tissue geometry and fibre orientation in the human sinoatrial node (SAN) and surrounding atrial muscle was integrated into the 3D model of the whole atria dissected from the Visible Human dataset. The anatomical models were combined with the heterogeneous atrial action potential (AP) models, and used to simulate the AP conduction in the human atria under various conditions: SAN pacemaking and atrial activation in the normal rhythm, break-down of regular AP wave-fronts during rapid atrial pacing, and the genesis of multiple re-entrant wavelets characteristic of AF. Contributions of different properties of the tissue to mechanisms of the normal rhythm and arrhythmogenesis were investigated. Primarily, the simulations showed that tissue heterogeneity caused the break-down of the normal AP wave-fronts at rapid pacing rates, which initiated a pair of re-entrant spiral waves; and tissue anisotropy resulted in a further break-down of the spiral waves into multiple meandering wavelets characteristic of AF. The 3D virtual atria model itself was incorporated into the torso model to simulate the body surface ECG patterns in the normal and arrhythmic conditions. Therefore, a state-of-the-art computational platform has been developed, which can be used for studying multi

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

    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.

  2. Computed tomographic imaging of the brain of normal neonatal foals

    L Cabrera

    2015-01-01

    Full Text Available The aim of this study was to provide a more complete description of normal cross-sectional anatomy of the neonatal brain of the foal and associated structures by computed tomography (CT and gross anatomical sections. Using a fourth-generation CT scanner, 2-mm contiguous transverse images were acquired from two neonatal 5-days-old Quarter horse foals. After the study the animals were euthanised for reasons unrelated to head pathology. To assist in the accurate identification of brain and associated structures, transverse CT images were obtained and compared with the corresponding frozen cross-sections of the head. CT images matched well with their corresponding transverse gross sections and provided good differentiation between the bones and the soft tissues of the head. These CT images are intended to be a useful initial anatomic reference in the interpretation for clinical CT imaging studies of the brain and associated structures in live neonatal foals.

  3. Quick, Accurate, Smart: 3D Computer Vision Technology Helps Assessing Confined Animals' Behaviour.

    Barnard, Shanis; Calderara, Simone; Pistocchi, Simone; Cucchiara, Rita; Podaliri-Vulpiani, Michele; Messori, Stefano; Ferri, Nicola

    2016-01-01

    Mankind directly controls the environment and lifestyles of several domestic species for purposes ranging from production and research to conservation and companionship. These environments and lifestyles may not offer these animals the best quality of life. Behaviour is a direct reflection of how the animal is coping with its environment. Behavioural indicators are thus among the preferred parameters to assess welfare. However, behavioural recording (usually from video) can be very time consuming and the accuracy and reliability of the output rely on the experience and background of the observers. The outburst of new video technology and computer image processing gives the basis for promising solutions. In this pilot study, we present a new prototype software able to automatically infer the behaviour of dogs housed in kennels from 3D visual data and through structured machine learning frameworks. Depth information acquired through 3D features, body part detection and training are the key elements that allow the machine to recognise postures, trajectories inside the kennel and patterns of movement that can be later labelled at convenience. The main innovation of the software is its ability to automatically cluster frequently observed temporal patterns of movement without any pre-set ethogram. Conversely, when common patterns are defined through training, a deviation from normal behaviour in time or between individuals could be assessed. The software accuracy in correctly detecting the dogs' behaviour was checked through a validation process. An automatic behaviour recognition system, independent from human subjectivity, could add scientific knowledge on animals' quality of life in confinement as well as saving time and resources. This 3D framework was designed to be invariant to the dog's shape and size and could be extended to farm, laboratory and zoo quadrupeds in artificial housing. The computer vision technique applied to this software is innovative in non

  4. Quick, Accurate, Smart: 3D Computer Vision Technology Helps Assessing Confined Animals' Behaviour.

    Shanis Barnard

    Full Text Available Mankind directly controls the environment and lifestyles of several domestic species for purposes ranging from production and research to conservation and companionship. These environments and lifestyles may not offer these animals the best quality of life. Behaviour is a direct reflection of how the animal is coping with its environment. Behavioural indicators are thus among the preferred parameters to assess welfare. However, behavioural recording (usually from video can be very time consuming and the accuracy and reliability of the output rely on the experience and background of the observers. The outburst of new video technology and computer image processing gives the basis for promising solutions. In this pilot study, we present a new prototype software able to automatically infer the behaviour of dogs housed in kennels from 3D visual data and through structured machine learning frameworks. Depth information acquired through 3D features, body part detection and training are the key elements that allow the machine to recognise postures, trajectories inside the kennel and patterns of movement that can be later labelled at convenience. The main innovation of the software is its ability to automatically cluster frequently observed temporal patterns of movement without any pre-set ethogram. Conversely, when common patterns are defined through training, a deviation from normal behaviour in time or between individuals could be assessed. The software accuracy in correctly detecting the dogs' behaviour was checked through a validation process. An automatic behaviour recognition system, independent from human subjectivity, could add scientific knowledge on animals' quality of life in confinement as well as saving time and resources. This 3D framework was designed to be invariant to the dog's shape and size and could be extended to farm, laboratory and zoo quadrupeds in artificial housing. The computer vision technique applied to this software is

  5. Quick, Accurate, Smart: 3D Computer Vision Technology Helps Assessing Confined Animals’ Behaviour

    Calderara, Simone; Pistocchi, Simone; Cucchiara, Rita; Podaliri-Vulpiani, Michele; Messori, Stefano; Ferri, Nicola

    2016-01-01

    Mankind directly controls the environment and lifestyles of several domestic species for purposes ranging from production and research to conservation and companionship. These environments and lifestyles may not offer these animals the best quality of life. Behaviour is a direct reflection of how the animal is coping with its environment. Behavioural indicators are thus among the preferred parameters to assess welfare. However, behavioural recording (usually from video) can be very time consuming and the accuracy and reliability of the output rely on the experience and background of the observers. The outburst of new video technology and computer image processing gives the basis for promising solutions. In this pilot study, we present a new prototype software able to automatically infer the behaviour of dogs housed in kennels from 3D visual data and through structured machine learning frameworks. Depth information acquired through 3D features, body part detection and training are the key elements that allow the machine to recognise postures, trajectories inside the kennel and patterns of movement that can be later labelled at convenience. The main innovation of the software is its ability to automatically cluster frequently observed temporal patterns of movement without any pre-set ethogram. Conversely, when common patterns are defined through training, a deviation from normal behaviour in time or between individuals could be assessed. The software accuracy in correctly detecting the dogs’ behaviour was checked through a validation process. An automatic behaviour recognition system, independent from human subjectivity, could add scientific knowledge on animals’ quality of life in confinement as well as saving time and resources. This 3D framework was designed to be invariant to the dog’s shape and size and could be extended to farm, laboratory and zoo quadrupeds in artificial housing. The computer vision technique applied to this software is innovative in non

  6. 3D modeling method for computer animate based on modified weak structured light method

    Xiong, Hanwei; Pan, Ming; Zhang, Xiangwei

    2010-11-01

    A simple and affordable 3D scanner is designed in this paper. Three-dimensional digital models are playing an increasingly important role in many fields, such as computer animate, industrial design, artistic design and heritage conservation. For many complex shapes, optical measurement systems are indispensable to acquiring the 3D information. In the field of computer animate, such an optical measurement device is too expensive to be widely adopted, and on the other hand, the precision is not as critical a factor in that situation. In this paper, a new cheap 3D measurement system is implemented based on modified weak structured light, using only a video camera, a light source and a straight stick rotating on a fixed axis. For an ordinary weak structured light configuration, one or two reference planes are required, and the shadows on these planes must be tracked in the scanning process, which destroy the convenience of this method. In the modified system, reference planes are unnecessary, and size range of the scanned objects is expanded widely. A new calibration procedure is also realized for the proposed method, and points cloud is obtained by analyzing the shadow strips on the object. A two-stage ICP algorithm is used to merge the points cloud from different viewpoints to get a full description of the object, and after a series of operations, a NURBS surface model is generated in the end. A complex toy bear is used to verify the efficiency of the method, and errors range from 0.7783mm to 1.4326mm comparing with the ground truth measurement.

  7. Computed tomographic appearance of mucormycosis; Computertomographisches Erscheinungsbild der pulmonalen Mukormykose

    Vogl, T.J.; Hinrichs, T.; Jacobi, V. [Frankfurt Univ. (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie; Boehme, A.; Hoelzer, D. [Frankfurt Univ. (Germany). Medizinische Klinik III, Haematologie/Onkologie

    2000-07-01

    Aim: Analysis of the morphological characteristics of pulmonary mucormycosis using computed tomography (CT). Material and methods: Prospective analysis of CT studies in 9 patients out of 19 patients with proven pulmonary mucormycosis. Results: Pulmonary mucormycosis was most frequently found in the upper lobe bilaterally (51% of all nodules). In 22% of the manifestations, the morphological criterion of a 'bird's nest' could be verified in CT, in 37% central necrotic areas were detected. In 37% an open bronchus was diagnosed, in 6% we observed bronchiectases. 43% of all nodules presented with a halo sign. In three patients we found pleural effusions, enlarged mediastinal lymph nodes were diagnosed in one patient. Conclusion: Computed tomography allows an improved diagnosis and therapeutic follow-up in patients suffering from pulmonary mucormycosis. (orig.) [German] Ziel: Analyse der morphologischen Charakteristika der pulmonalen Mukormykose in der Computertomographie. Material und Methodik: Retrospektive Analyse der computertomographischen Untersuchungen bei 9 Patienten aus einem Kollektiv von 19 Patienten mit gesicherter pulmonaler Mukormykose. Ergebnisse: Pulmonale Mukormanifestationen fanden sich bevorzugt im Oberlappen beidseits (51% aller Herde). Bei 22% der Herde konnte das morphologische Zeichen des 'bird's nest' verifiziert werden, bei 37% zeigten sich Einschmelzungen. In 37% der Herde liess sich ein offener Bronchus nachweisen, bei 6% beobachteten wir Bronchiektasen. 43% der Herde wiesen einen 'Halo' auf. Bei drei Patienten lagen Pleuraerguesse vor, eine Lymphknotenvergroesserung (>1 cm) zeigte sich bei einem Patienten. Schlussfolgerung: Die Computertomographie leistet einen wichtigen Beitrag zur Diagnose und Verlaufskontrolle der pulmonalen Mukormykose. (orig.)

  8. 3D-Ultrasound probe calibration for computer-guided diagnosis and therapy

    Baumann, Michael; Leroy, Antoine; Troccaz, Jocelyne

    2008-01-01

    With the emergence of swept-volume ultrasound (US) probes, precise and almost real-time US volume imaging has become available. This offers many new opportunities for computer guided diagnosis and therapy, 3-D images containing significantly more information than 2-D slices. However, computer guidance often requires knowledge about the exact position of US voxels relative to a tracking reference, which can only be achieved through probe calibration. In this paper we present a 3-D US probe calibration system based on a membrane phantom. The calibration matrix is retrieved by detection of a membrane plane in a dozen of US acquisitions of the phantom. Plane detection is robustly performed with the 2-D Hough transformation. The feature extraction process is fully automated, calibration requires about 20 minutes and the calibration system can be used in a clinical context. The precision of the system was evaluated to a root mean square (RMS) distance error of 1.15mm and to an RMS angular error of 0.61 degrees. The...

  9. Compute extremely low-frequency electromagnetic field exposure by 3-D impendance method

    2007-01-01

    A 3-D impedance method has been introduced to compute the electric currents induced in a human body exposed to extremely low-frequency electromagnetic field.The 3-D impedance method has been deduced from Maxwell equations and is put into the computation and simulation effectively to the visible human body model, which has 196×114×626 cells and more than 40 types of tissues.As the result, two representative cases are investigated.One is exposure of the human body to 100 μT (1 000 mG), the limit recommended by the International Commission on Non-Ionizing Radiation Protection for the public and the other one is the exposure of human body to 0.4 μT (4 mG), the level at which a statistical link appears with a doubled risk of development of childhood leukaemia.The distribution of induced current density can be obtained and the maximum of induced current are found to be 16 mA/m2 and 0.07 mA/m2.

  10. FaceWarehouse: a 3D facial expression database for visual computing.

    Cao, Chen; Weng, Yanlin; Zhou, Shun; Tong, Yiying; Zhou, Kun

    2014-03-01

    We present FaceWarehouse, a database of 3D facial expressions for visual computing applications. We use Kinect, an off-the-shelf RGBD camera, to capture 150 individuals aged 7-80 from various ethnic backgrounds. For each person, we captured the RGBD data of her different expressions, including the neutral expression and 19 other expressions such as mouth-opening, smile, kiss, etc. For every RGBD raw data record, a set of facial feature points on the color image such as eye corners, mouth contour, and the nose tip are automatically localized, and manually adjusted if better accuracy is required. We then deform a template facial mesh to fit the depth data as closely as possible while matching the feature points on the color image to their corresponding points on the mesh. Starting from these fitted face meshes, we construct a set of individual-specific expression blendshapes for each person. These meshes with consistent topology are assembled as a rank-3 tensor to build a bilinear face model with two attributes: identity and expression. Compared with previous 3D facial databases, for every person in our database, there is a much richer matching collection of expressions, enabling depiction of most human facial actions. We demonstrate the potential of FaceWarehouse for visual computing with four applications: facial image manipulation, face component transfer, real-time performance-based facial image animation, and facial animation retargeting from video to image.

  11. Fast computation of scattering from 3D complex structures by MLFMA

    Hu Jun; Nie Zaiping; Que Xiaofeng; Meng Min

    2008-01-01

    This paper introduces the research work on the extension of multilevel fast multipole algorithm (MLFMA) to 3D complex structures including coating object,thin dielectric sheet,composite dielectric and conductor,cavity.The impedance boundary condition is used for scattering from the object coated by thin lossy material.Instead of volume integral equation,surface integral equation is applied in case of thin dielectric sheet through resistive sheet boundary condition.To realize the fast computation of scattering from composite homogeneous dielectric and conductor,the surface integral equation based on equivalence principle is used.Compared with the traditional volume integral equation,the surface integral equation reduces greatly the number of unknowns.To compute conducting cavity with electrically large aperture,an electric field integral equation is applied.Some numerical results are given to demonstrate the validity and accuracy of the present methods.

  12. Applying 3D measurements and computer matching algorithms to two firearm examination proficiency tests.

    Ott, Daniel; Thompson, Robert; Song, Junfeng

    2017-02-01

    In order for a crime laboratory to assess a firearms examiner's training, skills, experience, and aptitude, it is necessary for the examiner to participate in proficiency testing. As computer algorithms for comparisons of pattern evidence become more prevalent, it is of interest to test algorithm performance as well, using these same proficiency examinations. This article demonstrates the use of the Congruent Matching Cell (CMC) algorithm to compare 3D topography measurements of breech face impressions and firing pin impressions from a previously distributed firearms proficiency test. In addition, the algorithm is used to analyze the distribution of many comparisons from a collection of cartridge cases used to construct another recent set of proficiency tests. These results are provided along with visualizations that help to relate the features used in optical comparisons by examiners to the features used by computer comparison algorithms.

  13. A review of automated image understanding within 3D baggage computed tomography security screening.

    Mouton, Andre; Breckon, Toby P

    2015-01-01

    Baggage inspection is the principal safeguard against the transportation of prohibited and potentially dangerous materials at airport security checkpoints. Although traditionally performed by 2D X-ray based scanning, increasingly stringent security regulations have led to a growing demand for more advanced imaging technologies. The role of X-ray Computed Tomography is thus rapidly expanding beyond the traditional materials-based detection of explosives. The development of computer vision and image processing techniques for the automated understanding of 3D baggage-CT imagery is however, complicated by poor image resolutions, image clutter and high levels of noise and artefacts. We discuss the recent and most pertinent advancements and identify topics for future research within the challenging domain of automated image understanding for baggage security screening CT.

  14. Computational Approach to 3D Modeling of the Lymph Node Geometry

    Alexey Kislitsyn

    2015-05-01

    Full Text Available In this study we present a computational approach to the generation of the major geometric structures of an idealized murine lymph node (LN. In this generation, we consider the major compartments such as the subcapsular sinus, B cell follicles, trabecular and medullar sinuses, blood vessels and the T cell zone with a primary focus on the fibroblastic reticular cell (FRC network. Confocal microscopy data of LN macroscopic structures and structural properties of the FRC network have been generated and utilized in the present model. The methodology sets a library of modules that can be used to assemble a solid geometric LN model and subsequently generate an adaptive mesh model capable of implementing transport phenomena. Overall, based on the use of high-resolution confocal microscopy and morphological analysis of cell 3D reconstructions, we have developed a computational model of the LN geometry, suitable for further investigation in studies of fluid transport and cell migration in this immunologically essential organ.

  15. Computed tomographic study in young epileptics in Kashmir, India

    Mohd Ashraf

    2013-07-01

    Full Text Available Background: Infectious diseases like neurocysticercosis and neurotuberculosis are endemic in Indian subcontinent and are important causes of epilepsy. Epileptic children are prone to have poor school performance, higher levels of anxiety and depression apart from low self esteem. These treatable condition could be easily picked up on neuroimaging like cranial computed tomography (CT scan and treated accordingly at an earliest. Objectives: To assess the role of cranial computed tomography scan in children having epilepsy. Material and Methods: Seventy two children between the age of 1 month and 14 years were prospectively enrolled, who had atleast two unprovoked seizures greater than 24 hours apart, and all those children where seizures result from acute central nervous system insult were meticulously excluded. Diagnosis of epilepsy was based on detailed history, thorough clinical examination, routine laboratory tests with additional specific tests like electroencephalogram (EEG and CT scan brain. Results: Males constituted 62.5% and females 37.5% of our sample (p=0.247. The EEG was abnormal in 68.1% of all subjects, among which EEG was abnormal in 69.8% of generalized seizures, 64.7% in partial seizures and 1% in undetermined seizures. The spectrum of various seizure types in our study was generalized seizures in 73.6%, partial seizures in 23.6% & undetermined seizures in 2.8%. The incidence of these lesions in hospitalized young epileptics was 31.9%, in order of their frequency, it was cerebral atrophy and dilated ventricle (18.8% each; calcifications (15.5%; encephalomalacia and pachygyria (9.4% each; HIE changes, tuberous sclerosis (6.3% each; leucodystrophy, thin corpus callosum, large cisterna magna, granuloma and periventricular leukomalacia (3.1% each. The intracranial structural lesions were present in 22.6% of generalized seizures, 64.7% of partial seizures, none of undetermined seizures (p=0.004. Conclusion: Abnormal cranial CT scan

  16. Using Computer-Aided Design Software and 3D Printers to Improve Spatial Visualization

    Katsio-Loudis, Petros; Jones, Millie

    2015-01-01

    Many articles have been published on the use of 3D printing technology. From prefabricated homes and outdoor structures to human organs, 3D printing technology has found a niche in many fields, but especially education. With the introduction of AutoCAD technical drawing programs and now 3D printing, learners can use 3D printed models to develop…

  17. [Recurrence paralysis: computed tomographic analysis of intrathoracic findings].

    Delorme, S; Knopp, M V; Kauczor, H U; Zuna, I; Trost, U; Haberkorn, U; van Kaick, G

    1992-09-01

    The long and singular course of the inferior (recurrent) laryngeal nerve makes it very vulnerable to infiltration by tumors of various locations. In particular, mediastinal and pulmonary lesions must be considered in the case of left vocal chord palsy. Recurrent nerve paralysis caused by a tumor indicates advanced disease. We retrospectively reviewed the computed tomography (CT) findings in 29 patients with bronchogenic carcinoma or mediastinal tumors and recurrent nerve paralysis with respect to the site, size and extent of the tumor and the lymph node status. The review revealed a marked predominance of left upper lobe tumors with extensive lymph node metastases to the anterior mediastinum and the aortopulmonary window. The extent of mediastinal involvement exceeded the average involvement in a control group of 30 randomly selected patients with bronchogenic carcinoma at the time of presentation. In all patients CT demonstrated tumor tissue which could have caused the paralysis at one or more sites along the anatomical course of the recurrent nerve. In most cases the tumor was located at the aortic arch. The left paratracheal region, right paratracheal region and right pulmonary apex were affected in one case each. We conclude that in patients with cancer, CT is a suitable method for localizing a recurrent nerve lesion.

  18. Computed Tomographic Evaluation of Presumptively Normal Canine Sternal Lymph Nodes.

    Iwasaki, Ryota; Mori, Takashi; Ito, Yusuke; Kawabe, Mifumi; Murakmi, Mami; Maruo, Kohji

    The sternal lymph nodes receive drainage from a wide variety of structures in the thoraco-abdominal region. Evaluation of these lymph nodes is essential, especially in cancer patients. Computed tomography (CT) can detect sternal lymph nodes more accurately than radiography or ultrasonography, and the criteria of the sternal lymphadenopathy are unknown. The purpose of this retrospective study was to describe the CT characteristics of the sternal lymph nodes in dogs considered unlikely to have lymphadenopathy. The ratio of the short axis dimension of the sternal lymph nodes to the thickness of the second sternebra was also investigated. At least one sternal lymph node was identified in each of the 152 dogs included in the study. The mean long axis and short axis dimensions were 0.700 cm and 0.368 cm, respectively. The mean ratio of the sternal lymph nodes to the second sternebrae was 0.457, and the 95% prediction interval ranged from 0.317 to 0.596 (almost a fixed value independent of body weight). These findings will be useful when evaluating sternal lymphadenopathy using CT.

  19. Lacunar infarcts in childhood. Clinical and computed tomographic correlations

    Nakano, Chizuko; Eda, Isematsu; Takashima, Sachio; Takeshita, Kenzo (Tottori Univ., Yonago (Japan). School of Medicine); Kanetoh, Yasuko

    1984-09-01

    Nine cases, ranging in age from 6 months to 9 years, were diagnosed as lacunar infarcts on computed tomography (CT). Hemiplegia developed rapidly or gradually in 8 cases. Three of 8 cases had transient ischemic attacks of hemiplegia. Other neurological deficits were dysarthria, aphasia, confusion and coarse tremor. One case was asymptomatic. Each of 8 cases had single lacuna and one case two lacunae on CT. These lacunae were localized in the internal capsule, the putamen or the caudate nucleus. Lacunae involving the internal capsule were associated with contralateral hemiplegia, whereas asymptomatic lacunae did not involve it. Severity of hemiplegia in the acute stage did not correlate with localization or size of lacunae. Moderate neurological sequelae were noticed in 3 cases, mild sequelae in two and none in three. The sequelae were related to the lacunae which involved the lateral lenticulostriate branch zone of the middle cerebral artery or larger areas. Prognosis did not correlate with the mode of onset or the severity of neurological signs in the acute stage. There were 2 cases with the occlusion of the left internal carotid artery or congenital heart disease, but the etiology of lacunae was unknown in the other cases.

  20. Computed tomographic features of afferent loop syndrome: pictorial essay

    Zissin, R. [Tel-Aviv Univ., Dept. of Diagnostic Imaging, Sapir Medical Center, Kfar Saba, Sackler Faculty of Medicine, Tel Aviv (Israel); Hertz, M. [Tel-Aviv Univ., Dept. of Diagnostic Imaging, Chaim Sheba Medical Center, Tel Hashomer, Tel Aviv (Israel); Paran, H. [Tel-Aviv Univ., Dept. of Diagnostic Imaging, Surgery ' A' , Sapir Medical Center, Kfar Saba, Sackler Faculty of Medicine, Tel Aviv (Israel); Osadchy, A. [Tel-Aviv Univ., Dept. of Diagnostic Imaging, Sapir Medical Center, Kfar Saba, Sackler Faculty of Medicine, Tel Aviv (Israel); Gayer, G. [Tel-Aviv Univ., Dept. of Diagnostic Imaging, Assaf Harofe Medical Center, Zrifin, Sackler Faculty of Medicine, Tel Aviv (Israel)

    2005-04-15

    This pictorial essay reviews the computed tomography (CT) findings of afferent loop syndrome (ALS) in various pathological conditions to demonstrate the contribution of a common imaging modality-that is, abdominal CT, used nowadays for various abdominal complaints-to the diagnosis of ALS. ALS is caused by obstruction of the duodenum and jejunum proximal to a gastrojejunostomy anastomosis. It is a rare complication after Billroth II subtotal gastrectomy and even more rare after total or subtotal gastrectomy with Roux-en-Y reconstruction. Although currently advanced medical treatment and endoscopic interventions have dramatically decreased the necessity of surgery for peptic ulcer disease, ALS may appear years after previously common operations. Alternatively, the use of surgical resection for early gastric cancer nowadays leads to an increasing rate of malignancy-related ALS. Clinically, ALS may be difficult to diagnose as its presentation may be vague and nonspecific, but it has a characteristic appearance on CT. Clinicians and radiologists should therefore be familiar with this rare complication. Prompt recognition and correct diagnosis of this syndrome and its probable etiology are important as a guide for treatment. This review illustrates the CT features of ALS in various conditions. (author)

  1. Computed tomographic evaluation of the portal vein in the hepatomas

    Lee, Kee Hyung; Lee, Seung Chul; Bae, Man Gil; Seo, Heung Suk; Kim, Soon Yong; Lee, Min Ho; Kee, Choon Suhk; Park, Kyung Nam [Hanyang University College of Medicine, Seoul (Korea, Republic of)

    1986-10-15

    Computed tomography and pornographic findings of 63 patients with hepatoma, undergone hepatic angiography and superior mesenteric pornography for evaluation of tumor and thrombosis of portal vein and determination of indication of transcatheter arterial embolization for palliative treatment of hepatoma from April, 85 to June, 86 in Hanyang university hospital, were reviewed. The results were as follows: 1. In 36 cases, portal vein thrombosis was detected during photography. Nineteen of 37 cases which revealed localized hepatoma in the right lobe of the liver showed portal vein thrombosis; 9 of 11 cases of the left lobe; 8 of 14 cases which were involved in entire liver revealed thrombosis. One case localized in the caudate lobe showed no evidence of invasion to portal vein. 2. Twenty-four of 34 cases with diffuse infiltrative hepatoma revealed portal vein thrombosis and the incidence of portal vein thrombosis in this type were higher than in the cases of the nodular type. 3. The portal vein thrombosis appeared as filling defects of low density in the lumen of the portal veins in CT and they did not reveal contrast enhancement. 4. CT revealed well the evidence of obstructions in the cases of portal vein thrombosis and the findings were well-corresponded to the findings of the superior mesenteric photography. 5. Five of the cases of the portal vein thrombosis were missed in the CT and the causes were considered as due to partial volume effect of enhanced portal vein with partial occlusion or arterioportal shunts. 6. Six of 13 cases with occlusion of main portal vein showed cavernous transformation and they were noted as multiple small enhanced vascularities around the porta hepatis in the CT. According to the results, we conclude that CT is a useful modality to detect the changes of the portal veins in the patients of the hepatoma.

  2. Novel computed tomographic chest metrics to detect pulmonary hypertension

    Li Chin-Shang

    2011-03-01

    Full Text Available Abstract Background Early diagnosis of pulmonary hypertension (PH can potentially improve survival and quality of life. Detecting PH using echocardiography is often insensitive in subjects with lung fibrosis or hyperinflation. Right heart catheterization (RHC for the diagnosis of PH adds risk and expense due to its invasive nature. Pre-defined measurements utilizing computed tomography (CT of the chest may be an alternative non-invasive method of detecting PH. Methods This study retrospectively reviewed 101 acutely hospitalized inpatients with heterogeneous diagnoses, who consecutively underwent CT chest and RHC during the same admission. Two separate teams, each consisting of a radiologist and pulmonologist, blinded to clinical and RHC data, individually reviewed the chest CT's. Results Multiple regression analyses controlling for age, sex, ascending aortic diameter, body surface area, thoracic diameter and pulmonary wedge pressure showed that a main pulmonary artery (PA diameter ≥29 mm (odds ratio (OR = 4.8, right descending PA diameter ≥19 mm (OR = 7.0, true right descending PA diameter ≥ 16 mm (OR = 4.1, true left descending PA diameter ≥ 21 mm (OR = 15.5, right ventricular (RV free wall ≥ 6 mm (OR = 30.5, RV wall/left ventricular (LV wall ratio ≥0.32 (OR = 8.8, RV/LV lumen ratio ≥1.28 (OR = 28.8, main PA/ascending aorta ratio ≥0.84 (OR = 6.0 and main PA/descending aorta ratio ≥ 1.29 (OR = 5.7 were significant predictors of PH in this population of hospitalized patients. Conclusion This combination of easily measured CT-based metrics may, upon confirmatory studies, aid in the non-invasive detection of PH and hence in the determination of RHC candidacy in acutely hospitalized patients.

  3. Simulation of engine cooling with coupled 1D and 3D flow computation; Simulation der Motorkuehlung mit Hilfe gekoppelter 1D- und 3D-Stroemungsberechnung

    Grafenberger, P.; Klinner, P.; Nefischer, P. [BMW Motoren GmbH, Steyr (Austria); Klingebiel, F. [AMSTRAL Engineering fuer Stroemungsmechanik GmbH, Idstein (Germany)

    2000-04-01

    Shorting the development time for new engines and vehicles is leading to the increasing use of computational design and simulation methods in the automotive industry. For several years now, both one-dimensional and three-dimensional flow computation have been used successfully in the development of cooling systems. However, the fact that less hardware is used in the early development stages makes new demands on the quality and quantity of these simulation results. BMW's diesel development division has been able to improve the quality of the results and to reduce the processing time by improving the model quality and by coupling existing 1D and 3D computational fluid dynamic programmes. (orig.) [German] Die Verkuerzung der Entwicklungszeit neuer Motoren und Automobile fuehrt zu einem verstaerkten Einsatz von rechnergestuetzten Konstruktions- und Simulationsmethoden in der Fahrzeugindustrie. Sowohl eindimensionale als auch dreidimensionale Stroemungsberechnungen werden seit Jahren erfolgreich bei der Entwicklung von Kuehlsystemen eingesetzt. Der Entfall von Hardware-Baugruppen in der fruehen Entwicklungsphase stellt jedoch neue Anforderungen an die Qualitaet und Quantitaet dieser Simulationsergebnisse. Durch Verbesserung der Modellqualitaet und durch Kopplung vorhandener 1D- und 3D-Stroemungsberechnungsprogramme konnten in der Dieselmotorenentwicklung von BMW die Qualitaet der Ergebnisse und die Bearbeitungsgeschwindigkeit deutlich gesteigert werden. (orig.)

  4. "Let's get physical": advantages of a physical model over 3D computer models and textbooks in learning imaging anatomy.

    Preece, Daniel; Williams, Sarah B; Lam, Richard; Weller, Renate

    2013-01-01

    Three-dimensional (3D) information plays an important part in medical and veterinary education. Appreciating complex 3D spatial relationships requires a strong foundational understanding of anatomy and mental 3D visualization skills. Novel learning resources have been introduced to anatomy training to achieve this. Objective evaluation of their comparative efficacies remains scarce in the literature. This study developed and evaluated the use of a physical model in demonstrating the complex spatial relationships of the equine foot. It was hypothesized that the newly developed physical model would be more effective for students to learn magnetic resonance imaging (MRI) anatomy of the foot than textbooks or computer-based 3D models. Third year veterinary medicine students were randomly assigned to one of three teaching aid groups (physical model; textbooks; 3D computer model). The comparative efficacies of the three teaching aids were assessed through students' abilities to identify anatomical structures on MR images. Overall mean MRI assessment scores were significantly higher in students utilizing the physical model (86.39%) compared with students using textbooks (62.61%) and the 3D computer model (63.68%) (P computer model groups (P = 0.685). Student feedback was also more positive in the physical model group compared with both the textbook and 3D computer model groups. Our results suggest that physical models may hold a significant advantage over alternative learning resources in enhancing visuospatial and 3D understanding of complex anatomical architecture, and that 3D computer models have significant limitations with regards to 3D learning.

  5. Segmentation process significantly influences the accuracy of 3D surface models derived from cone beam computed tomography

    Fourie, Zacharias; Damstra, Janalt; Schepers, Rutger H; Gerrits, Pieter; Ren, Yijin

    2012-01-01

    AIMS: To assess the accuracy of surface models derived from 3D cone beam computed tomography (CBCT) with two different segmentation protocols. MATERIALS AND METHODS: Seven fresh-frozen cadaver heads were used. There was no conflict of interests in this study. CBCT scans were made of the heads and 3D

  6. The influence of the segmentation process on 3D measurements from cone beam computed tomography-derived surface models

    Engelbrecht, Willem P.; Fourie, Zacharias; Damstra, Janalt; Gerrits, Peter O.; Ren, Yijin

    2013-01-01

    To compare the accuracy of linear and angular measurements between cephalometric and anatomic landmarks on surface models derived from 3D cone beam computed tomography (CBCT) with two different segmentation protocols was the aim of this study. CBCT scans were made of cadaver heads and 3D surface mod

  7. The Effects of 3D Computer Modelling on Conceptual Change about Seasons and Phases of the Moon

    Kucukozer, Huseyin

    2008-01-01

    In this study, prospective science teachers' misconceptions about the seasons and the phases of the Moon were determined, and then the effects of 3D computer modelling on their conceptual changes were investigated. The topics were covered in two classes with a total of 76 students using a predict-observe-explain strategy supported by 3D computer…

  8. Soft computing approach to 3D lung nodule segmentation in CT.

    Badura, P; Pietka, E

    2014-10-01

    This paper presents a novel, multilevel approach to the segmentation of various types of pulmonary nodules in computed tomography studies. It is based on two branches of computational intelligence: the fuzzy connectedness (FC) and the evolutionary computation. First, the image and auxiliary data are prepared for the 3D FC analysis during the first stage of an algorithm - the masks generation. Its main goal is to process some specific types of nodules connected to the pleura or vessels. It consists of some basic image processing operations as well as dedicated routines for the specific cases of nodules. The evolutionary computation is performed on the image and seed points in order to shorten the FC analysis and improve its accuracy. After the FC application, the remaining vessels are removed during the postprocessing stage. The method has been validated using the first dataset of studies acquired and described by the Lung Image Database Consortium (LIDC) and by its latest release - the LIDC-IDRI (Image Database Resource Initiative) database.

  9. A Method for Identifying Contours in Processing Digital Images from Computer Tomograph

    Roşu, Şerban; Pater, Flavius; Costea, Dan; Munteanu, Mihnea; Roşu, Doina; Fratila, Mihaela

    2011-09-01

    The first step in digital processing of two-dimensional computed tomography images is to identify the contour of component elements. This paper deals with the collective work of specialists in medicine and applied mathematics in computer science on elaborating new algorithms and methods in medical 2D and 3D imagery.

  10. A 3-D Computational Study of a Variable Camber Continuous Trailing Edge Flap (VCCTEF) Spanwise Segment

    Kaul, Upender K.; Nguyen, Nhan T.

    2015-01-01

    Results of a computational study carried out to explore the effects of various elastomer configurations joining spanwise contiguous Variable Camber Continuous Trailing Edge Flap (VCCTEF) segments are reported here. This research is carried out as a proof-of-concept study that will seek to push the flight envelope in cruise with drag optimization as the objective. The cruise conditions can be well off design such as caused by environmental conditions, maneuvering, etc. To handle these off-design conditions, flap deflection is used so when the flap is deflected in a given direction, the aircraft angle of attack changes accordingly to maintain a given lift. The angle of attack is also a design parameter along with the flap deflection. In a previous 2D study,1 the effect of camber was investigated and the results revealed some insight into the relative merit of various camber settings of the VCCTEF. The present state of the art has not advanced sufficiently to do a full 3-D viscous analysis of the whole NASA Generic Transport Model (GTM) wing with VCCTEF deployed with elastomers. Therefore, this study seeks to explore the local effects of three contiguous flap segments on lift and drag of a model devised here to determine possible trades among various flap deflections to achieve desired lift and drag results. Although this approach is an approximation, it provides new insights into the "local" effects of the relative deflections of the contiguous spanwise flap systems and various elastomer segment configurations. The present study is a natural extension of the 2-D study to assess these local 3-D effects. Design cruise condition at 36,000 feet at free stream Mach number of 0.797 and a mean aerodynamic chord (MAC) based Reynolds number of 30.734x10(exp 6) is simulated for an angle of attack (AoA) range of 0 to 6 deg. In the previous 2-D study, the calculations revealed that the parabolic arc camber (1x2x3) and circular arc camber (VCCTEF222) offered the best L

  11. Analysis of 3D Prints by X-ray Computed Microtomography and Terahertz Pulsed Imaging

    Markl, Daniel; Zeitler, J Axel; Rasch, Cecilie

    2016-01-01

    PURPOSE: A 3D printer was used to realise compartmental dosage forms containing multiple active pharmaceutical ingredient (API) formulations. This work demonstrates the microstructural characterisation of 3D printed solid dosage forms using X-ray computed microtomography (XμCT) and terahertz pulsed...... imaging (TPI). METHODS: Printing was performed with either polyvinyl alcohol (PVA) or polylactic acid (PLA). The structures were examined by XμCT and TPI. Liquid self-nanoemulsifying drug delivery system (SNEDDS) formulations containing saquinavir and halofantrine were incorporated into the 3D printed...... was characterised by XμCT and TPI on the basis of the computer-aided design (CAD) models of the dosage form (compartmentalised PVA structures were 7.5 ± 0.75% larger than designed; n = 3). CONCLUSIONS: The 3D printer can reproduce specific structures very accurately, whereas the 3D prints can deviate from...

  12. 3D FEA Computation of the CLIC Machine Detector Interface Magnets

    Bartalesi, A

    2012-01-01

    A critical aspect of the Compact Linear Collider (CLIC) design is represented by the Accelerator/Experiment interface (called Machine Detector Interface or MDI). In the 3 TeV CLIC layout, the final focus QD0 quadrupole will be located inside the end-cap of the detector itself. This complex MDI scenario required to be simulated with a full 3D-FE analysis. This study was critical to check and control the magnetic cross-talk between the detector solenoid and the final focus magnet and therefore to optimize the design of an “antisolenoids” system needed to shield the QD0 and the e-/e+ beams from the detector magnetic field. In this paper the development and evolution of the computational FE model is presented together with the results obtained and their implication on the CLIC MDI design.

  13. Fatigue of hybrid glass/carbon composites: 3D computational studies

    Dai, Gaoming; Mishnaevsky, Leon

    2014-01-01

    3D computational simulations of fatigue of hybrid carbon/glass fiber reinforced composites is carried out using X-FEM and multifiber unit cell models. A new software code for the automatic generation of unit cell multifiber models of composites with randomly misaligned fibers of various properties...... and geometrical parameters is developed. With the use of this program code and the X-FEM method, systematic investigations of the effect of microstructure of hybrid composites (fraction of carbon versus glass fibers, misalignment, and interface strength) and the loading conditions (tensile versus compression...... cyclic loading effects) on fatigue behavior of the materials are carried out. It was demonstrated that the higher fraction of carbon fibers in hybrid composites is beneficial for the fatigue lifetime of the composites under tension-tension cyclic loading, but might have negative effect on the lifetime...

  14. ROLE OF COMPUTED TOMOGRAPHY AND 3D RECONSTRUCTIONS IN PELVIC RIM AND ACETABULAR FRACTURES

    Somasekhar

    2015-03-01

    Full Text Available To determine the role of computed tomography and 3D Reconstructions in classification of pelvic rim and acetabular fractures and assessing possible changes in fracture classification . We collected retrospective information in a period of 18 months in our institution , of patients with pelvic injuries considering --- demographic data , radiological examination performed and the moment when it was performed , fracture classification and management . In 12 cases ( 54% there were isolated pelvic rim fr actures and 7 cases of isolated acetabular fractures ( 32% and 3 cases ( 14% involving both . After the CT scan was obtained , the initial classification was changed in five cases ( 22 . 7% . Tridimensional CT based modeling is very helpful in the classificati on of pelvic fractures and is a complement of the plain X - ray .

  15. 3-D reconstruction of an ancient Egyptian mummy using X-ray computer tomography.

    Baldock, C; Hughes, S W; Whittaker, D K; Taylor, J; Davis, R; Spencer, A J; Tonge, K; Sofat, A

    1994-12-01

    Computer tomography has been used to image and reconstruct in 3-D an Egyptian mummy from the collection of the British Museum. This study of Tjentmutengebtiu, a priestess from the 22nd dynasty (945-715 BC) revealed invaluable information of a scientific, Egyptological and palaeopathological nature without mutilation and destruction of the painted cartonnage case or linen wrappings. Precise details on the removal of the brain through the nasal cavity and the viscera from the abdominal cavity were obtained. The nature and composition of the false eyes were investigated. The detailed analysis of the teeth provided a much closer approximation of age at death. The identification of materials used for the various amulets including that of the figures placed in the viscera was graphically demonstrated using this technique.

  16. Roughness receptivity studies in a 3-D boundary layer - Flight tests and computations

    Carpenter, Andrew L.; Saric, William S.; Reed, Helen L.

    The receptivity of 3-D boundary layers to micron-sized, spanwise-periodic Discrete Roughness Elements (DREs) was studied. The DREs were applied to the leading edge of a 30-degree swept-wing at the wavelength of the most unstable disturbance. In this case, calibrated, multi-element hotfilm sensors were used to measure disturbance wall shear stress. The roughness height was varied from 0 to 50 microns. Thus, the disturbance-shear-stress amplitude variations were determined as a function of modulated DRE heights. The computational work was conducted parallel to the flight experiments. The complete viscous flowfield over the O-2 aircraft with the SWIFT model mounted on the port wing store pylon was successfully modeled and validated with the flight data. This highly accurate basic-state solution was incorporated into linear stability calculations and the wave growth associated with the crossflow instability was calculated.

  17. A New Energy-Based Method for 3-D Finite-Element Nonlinear Flux Linkage computation of Electrical Machines

    Lu, Kaiyuan; Rasmussen, Peter Omand; Ritchie, Ewen

    2011-01-01

    This paper presents a new method for computation of the nonlinear flux linkage in 3-D finite-element models (FEMs) of electrical machines. Accurate computation of the nonlinear flux linkage in 3-D FEM is not an easy task. Compared to the existing energy-perturbation method, the new technique......-perturbation method. The new method proposed is validated using experimental results on two different permanent magnet machines....

  18. Computation of a high-resolution MRI 3D stereotaxic atlas of the sheep brain.

    Ella, Arsène; Delgadillo, José A; Chemineau, Philippe; Keller, Matthieu

    2017-02-15

    The sheep model was first used in the fields of animal reproduction and veterinary sciences and then was utilized in fundamental and preclinical studies. For more than a decade, magnetic resonance (MR) studies performed on this model have been increasingly reported, especially in the field of neuroscience. To contribute to MR translational neuroscience research, a brain template and an atlas are necessary. We have recently generated the first complete T1-weighted (T1W) and T2W MR population average images (or templates) of in vivo sheep brains. In this study, we 1) defined a 3D stereotaxic coordinate system for previously established in vivo population average templates; 2) used deformation fields obtained during optimized nonlinear registrations to compute nonlinear tissues or prior probability maps (nlTPMs) of cerebrospinal fluid (CSF), gray matter (GM), and white matter (WM) tissues; 3) delineated 25 external and 28 internal sheep brain structures by segmenting both templates and nlTPMs; and 4) annotated and labeled these structures using an existing histological atlas. We built a quality high-resolution 3D atlas of average in vivo sheep brains linked to a reference stereotaxic space. The atlas and nlTPMs, associated with previously computed T1W and T2W in vivo sheep brain templates and nlTPMs, provide a complete set of imaging space that are able to be imported into other imaging software programs and could be used as standardized tools for neuroimaging studies or other neuroscience methods, such as image registration, image segmentation, identification of brain structures, implementation of recording devices, or neuronavigation. J. Comp. Neurol. 525:676-692, 2017. © 2016 Wiley Periodicals, Inc.

  19. Real-time computer-generated integral imaging and 3D image calibration for augmented reality surgical navigation.

    Wang, Junchen; Suenaga, Hideyuki; Liao, Hongen; Hoshi, Kazuto; Yang, Liangjing; Kobayashi, Etsuko; Sakuma, Ichiro

    2015-03-01

    Autostereoscopic 3D image overlay for augmented reality (AR) based surgical navigation has been studied and reported many times. For the purpose of surgical overlay, the 3D image is expected to have the same geometric shape as the original organ, and can be transformed to a specified location for image overlay. However, how to generate a 3D image with high geometric fidelity and quantitative evaluation of 3D image's geometric accuracy have not been addressed. This paper proposes a graphics processing unit (GPU) based computer-generated integral imaging pipeline for real-time autostereoscopic 3D display, and an automatic closed-loop 3D image calibration paradigm for displaying undistorted 3D images. Based on the proposed methods, a novel AR device for 3D image surgical overlay is presented, which mainly consists of a 3D display, an AR window, a stereo camera for 3D measurement, and a workstation for information processing. The evaluation on the 3D image rendering performance with 2560×1600 elemental image resolution shows the rendering speeds of 50-60 frames per second (fps) for surface models, and 5-8 fps for large medical volumes. The evaluation of the undistorted 3D image after the calibration yields sub-millimeter geometric accuracy. A phantom experiment simulating oral and maxillofacial surgery was also performed to evaluate the proposed AR overlay device in terms of the image registration accuracy, 3D image overlay accuracy, and the visual effects of the overlay. The experimental results show satisfactory image registration and image overlay accuracy, and confirm the system usability.

  20. Enabling 3D-Liver Perfusion Mapping from MR-DCE Imaging Using Distributed Computing

    Benjamin Leporq

    2013-01-01

    Full Text Available An MR acquisition protocol and a processing method using distributed computing on the European Grid Infrastructure (EGI to allow 3D liver perfusion parametric mapping after Magnetic Resonance Dynamic Contrast Enhanced (MR-DCE imaging are presented. Seven patients (one healthy control and six with chronic liver diseases were prospectively enrolled after liver biopsy. MR-dynamic acquisition was continuously performed in free-breathing during two minutes after simultaneous intravascular contrast agent (MS-325 blood pool agent injection. Hepatic capillary system was modeled by a 3-parameters one-compartment pharmacokinetic model. The processing step was parallelized and executed on the EGI. It was modeled and implemented as a grid workflow using the Gwendia language and the MOTEUR workflow engine. Results showed good reproducibility in repeated processing on the grid. The results obtained from the grid were well correlated with ROI-based reference method ran locally on a personal computer. The speed-up range was 71 to 242 with an average value of 126. In conclusion, distributed computing applied to perfusion mapping brings significant speed-up to quantification step to be used for further clinical studies in a research context. Accuracy would be improved with higher image SNR accessible on the latest 3T MR systems available today.

  1. Enabling 3D-Liver Perfusion Mapping from MR-DCE Imaging Using Distributed Computing.

    Leporq, Benjamin; Camarasu-Pop, Sorina; Davila-Serrano, Eduardo E; Pilleul, Frank; Beuf, Olivier

    2013-01-01

    An MR acquisition protocol and a processing method using distributed computing on the European Grid Infrastructure (EGI) to allow 3D liver perfusion parametric mapping after Magnetic Resonance Dynamic Contrast Enhanced (MR-DCE) imaging are presented. Seven patients (one healthy control and six with chronic liver diseases) were prospectively enrolled after liver biopsy. MR-dynamic acquisition was continuously performed in free-breathing during two minutes after simultaneous intravascular contrast agent (MS-325 blood pool agent) injection. Hepatic capillary system was modeled by a 3-parameters one-compartment pharmacokinetic model. The processing step was parallelized and executed on the EGI. It was modeled and implemented as a grid workflow using the Gwendia language and the MOTEUR workflow engine. Results showed good reproducibility in repeated processing on the grid. The results obtained from the grid were well correlated with ROI-based reference method ran locally on a personal computer. The speed-up range was 71 to 242 with an average value of 126. In conclusion, distributed computing applied to perfusion mapping brings significant speed-up to quantification step to be used for further clinical studies in a research context. Accuracy would be improved with higher image SNR accessible on the latest 3T MR systems available today.

  2. Advances in tomographic PIV

    Novara, M.

    2013-01-01

    This research deals with advanced developments in 3D particle image velocimetry based on the tomographic PIV technique (Tomo-PIV). The latter is a relatively recent measurement technique introduced by Elsinga et al. in 2005, which is based on the tomographic reconstruction of particle tracers in thr

  3. A 3D computer-aided design system applied to diagnosis and treatment planning in orthodontics and orthognathic surgery.

    Motohashi, N; Kuroda, T

    1999-06-01

    The purpose of this article is to describe a newly developed 3D computer-aided design (CAD) system for the diagnostic set-up of casts in orthodontic diagnosis and treatment planning, and its preliminary clinical applications. The system comprises a measuring unit which obtains 3D information from the dental model using laser scanning, and a personal computer to generate the 3D graphics. When measuring the 3D shape of the model, to minimize blind sectors, the model is scanned from two different directions with the slit-ray laser beam by rotating the mounting angle of the model on the measuring device. For computed simulation of tooth movement, the representative planes, defined by the anatomical reference points, are formed for each individual tooth and are arranged along a guideline descriptive of the individual arch form. Subsequently, the 3D shape is imparted to each of the teeth arranged on the representative plane to form an arrangement of the 3D profile. When necessary, orthognathic surgery can be simulated by moving the mandibular dental arch three-dimensionally to establish the optimum occlusal relationship. Compared with hand-made set-up models, the computed diagnostic cast has advantages such as high-speed processing and quantitative evaluation on the amount of 3D movement of the individual tooth relative to the craniofacial plane. Trial clinical applications demonstrated that the use of this system facilitated the otherwise complicated and time-consuming mock surgery for treatment planning in orthognathic surgery.

  4. Multidetector computed tomographic and magnetic resonance enterography in children: state of the art.

    Hammer, Matthew R; Podberesky, Daniel J; Dillman, Jonathan R

    2013-07-01

    Advanced multidetector computed tomographic and magnetic resonance imaging techniques (CT and MR enterography, respectively), designed to provide detailed images of the bowel and mesentery, can be successfully performed in children of all ages, frequently without sedation. Cross-sectional enterography allows for noninvasive diagnosis, detection of various disease-related complications and extraintestinal manifestations, and monitoring of bowel-wall inflammation in pediatric inflammatory bowel disease (IBD). This article provides a contemporary review of CT and MR enterography in the pediatric population, including up-to-date techniques and clinical applications. A range of bowel abnormalities is illustrated, with an emphasis on IBD and its many abdominopelvic manifestations.

  5. Computed tomographic mammography. Diagnosis of mammographically and clinically occult carcinoma of the breast.

    Sibala, J L; Chang, C H; Lin, F; Jewell, W R

    1981-01-01

    If breast cancer can be detected early, while it is still localized and before it can be palpated, the prognosis for cure is excellent. Heretofore, conventional mammography has been the only means available to detect cancer at such an early stage. Two cases of minimal breast carcinoma measuring less than 5 mm in diameter have been detected and correctly diagnosed using computed tomographic mammography (CT/M). Both cases occurred in fatty breasts and were clinically and mammographically occult. These cases demonstrate the value of CT/M in the diagnosis of minimal breast carcinoma that would have been missed otherwise.

  6. Automating the segmentation of medical images for the production of voxel tomographic computational models.

    Caon, M; Mohyla, J

    2001-12-01

    Radiation dosimetry for the diagnostic medical imaging procedures performed on humans requires anatomically accurate, computational models. These may be constructed from medical images as voxel-based tomographic models. However, they are time consuming to produce and as a consequence, there are few available. This paper discusses the emergence of semi-automatic segmentation techniques and describes an application (iRAD) written in Microsoft Visual Basic that allows the bitmap of a medical image to be segmented interactively and semi-automatically while displayed in Microsoft Excel. iRAD will decrease the time required to construct voxel models.

  7. A Computational Method for 3D Anisotropic Travel-time Tomography of Rocks in the Laboratory

    Ghofranitabari, Mehdi; Young, R. Paul

    2013-04-01

    True triaxial loading in the laboratory applies three principal stresses on a cubic rock specimen. Elliptical anisotropy and distributed heterogeneities are introduced in the rock due to closure and opening of the pre-existing cracks and creation and growth of the new aligned cracks. The rock sample is tested in a Geophysical Imaging Cell that is armed with an Acoustic Emission monitoring system which can perform transducer to transducer velocity surveys to image velocity structure of the sample during the experiment. Ultrasonic travel-time tomography as a non-destructive method outfits a map of wave propagation velocity in the sample in order to detect the uniformly distributed or localised heterogeneities and provide the spatial variation and temporal evolution of induced damages in rocks at various stages of loading. The rock sample is partitioned into cubic grid cells as model space. Ray-based tomography method measuring body wave travel time along ray paths between pairs of emitting and receiving transducers is used to calculate isotropic ray-path segment matrix elements (Gij) which contain segment lengths of the ith ray in the jth cell in three dimensions. Synthetic P wave travel times are computed between pairs of transducers in a hypothetical isotropic heterogeneous cubic sample as data space along with an error due to precision of measurement. 3D strain of the squeezed rock and the consequent geometrical deformation is also included in computations for further accuracy. Singular Value Decomposition method is used for the inversion from data space to model space. In the next step, the anisotropic ray-path segment matrix and the corresponded data space are computed for hypothetical anisotropic heterogeneous samples based on the elliptical anisotropic model of velocity which is obtained from the real laboratory experimental data. The method is examined for several different synthetic heterogeneous models. An "Inaccuracy factor" is utilized to inquire the

  8. A Fast Full Tensor Gravity computation algorithm for High Resolution 3D Geologic Interpretations

    Jayaram, V.; Crain, K.; Keller, G. R.

    2011-12-01

    We present an algorithm to rapidly calculate the vertical gravity and full tensor gravity (FTG) values due to a 3-D geologic model. This algorithm can be implemented on single, multi-core CPU and graphical processing units (GPU) architectures. Our technique is based on the line element approximation with a constant density within each grid cell. This type of parameterization is well suited for high-resolution elevation datasets with grid size typically in the range of 1m to 30m. The large high-resolution data grids in our studies employ a pre-filtered mipmap pyramid type representation for the grid data known as the Geometry clipmap. The clipmap was first introduced by Microsoft Research in 2004 to do fly-through terrain visualization. This method caches nested rectangular extents of down-sampled data layers in the pyramid to create view-dependent calculation scheme. Together with the simple grid structure, this allows the gravity to be computed conveniently on-the-fly, or stored in a highly compressed format. Neither of these capabilities has previously been available. Our approach can perform rapid calculations on large topographies including crustal-scale models derived from complex geologic interpretations. For example, we used a 1KM Sphere model consisting of 105000 cells at 10m resolution with 100000 gravity stations. The line element approach took less than 90 seconds to compute the FTG and vertical gravity on an Intel Core i7 CPU at 3.07 GHz utilizing just its single core. Also, unlike traditional gravity computational algorithms, the line-element approach can calculate gravity effects at locations interior or exterior to the model. The only condition that must be met is the observation point cannot be located directly above the line element. Therefore, we perform a location test and then apply appropriate formulation to those data points. We will present and compare the computational performance of the traditional prism method versus the line element

  9. 3D Animation Essentials

    Beane, Andy

    2012-01-01

    The essential fundamentals of 3D animation for aspiring 3D artists 3D is everywhere--video games, movie and television special effects, mobile devices, etc. Many aspiring artists and animators have grown up with 3D and computers, and naturally gravitate to this field as their area of interest. Bringing a blend of studio and classroom experience to offer you thorough coverage of the 3D animation industry, this must-have book shows you what it takes to create compelling and realistic 3D imagery. Serves as the first step to understanding the language of 3D and computer graphics (CG)Covers 3D anim

  10. Multislice computed tomography angiography in the diagnosis of cardiovascular disease: 3D visualizations

    Zhonghua Sun

    2011-01-01

    Multislice computed tomography (CT) has been widely used in clinical practice for the diagnosis of cardiovascular disease due to its reduced invasiveness and high spatial and temporal resolution.As a reliable alternative to conventional angiography,multislice CT angiography has been recognized as the method of choice for detecting and diagnosing head and neck vascular disease,abdominal aortic aneurysm,aortic dissection,and pulmonary embolism.In patients with suspected coronary artery disease,although invasive coronary angiography still remains as the gold standard technique,multislice CT angiography demonstrates high diagnostic accuracy; in selected patients,it is considered as the first-line technique.The imaging diagnosis of cardiovascular disease is based on a combination of two-dimensional (2D) and three-dimensional (3D) visualization tools to enhance the diagnostic value.This is facilitated by reconstructed visualizations which provide additional information about the extent of the disease,an accurate assessment of the spatial relationship between normal structures and pathological changes,and pre-operative planning and post-procedure follow-up.The aim of the present article is to present an overview of the diagnostic performance of various 2D and 3D CT visualizations in cardiovascular disease,including multiplanar reformation,maximum intensity projection,volume rendering,and virtual intravascular endoscopy.The recognition of the potential value of these visualizations will assist clinicians in efficiently using the muitislice CT imaging modality for the diagnostic management of patients with cardiovascular disease.

  11. Potential hazards of viewing 3-D stereoscopic television, cinema and computer games: a review.

    Howarth, Peter A

    2011-03-01

    The visual stimulus provided by a 3-D stereoscopic display differs from that of the real world because the image provided to each eye is produced on a flat surface. The distance from the screen to the eye remains fixed, providing a single focal distance, but the introduction of disparity between the images allows objects to be located geometrically in front of, or behind, the screen. Unlike in the real world, the stimulus to accommodation and the stimulus to convergence do not match. Although this mismatch is used positively in some forms of Orthoptic treatment, a number of authors have suggested that it could negatively lead to the development of asthenopic symptoms. From knowledge of the zone of clear, comfortable, single binocular vision one can predict that, for people with normal binocular vision, adverse symptoms will not be present if the discrepancy is small, but are likely if it is large, and that what constitutes 'large' and 'small' are idiosyncratic to the individual. The accommodation-convergence mismatch is not, however, the only difference between the natural and the artificial stimuli. In the former case, an object located in front of, or behind, a fixated object will not only be perceived as double if the images fall outside Panum's fusional areas, but it will also be defocused and blurred. In the latter case, however, it is usual for the producers of cinema, TV or computer game content to provide an image that is in focus over the whole of the display, and as a consequence diplopic images will be sharply in focus. The size of Panum's fusional area is spatial frequency-dependent, and because of this the high spatial frequencies present in the diplopic 3-D image will provide a different stimulus to the fusion system from that found naturally.

  12. 3-D Computational Modelling of Oblique Continental Collision near South Island, New Zealand

    Karatun, L.; Pysklywec, R. N.

    2015-12-01

    The research explores the highly oblique continental convergence at the South Island of New Zealand, considering the fundamental geodynamic mechanisms of sub-crustal lithospheric deformation during the orogenesis. In addition to the high velocity of along-strike plate motion, the oppositely verging subduction zones bounding the collision make the problem inherently three-dimensional. To study such factors during orogenesis, we conduct 3D computational modelling and present the results of a series of new experiments configured for the oblique South Island collision. The geodynamic modelling uses ASPECT - a robust highly-scalable and extendable geodynamic code featuring adaptive mesh refinement and complex rheologies. The model domain is defined by a box with prescribed velocities on the left and right faces with varied ratio of convergent versus strike-slip components, periodic boundary conditions for the front and back faces, free surface on top, and free slip at the bottom. Two different rheology types are used: brittle (pressure-, strain rate-, and material strength-dependent) for crust and visco-plastic (temperature-, pressure- and strain rate-dependent) for mantle. The obtained results provide insight into the behaviour of the lithosphere under the situation of young oblique convergence. We focus on the development of the mantle lithosphere, considering how the morphology of the sub-crustal orogenic root evolves during the convergent/strike-slip plate motions. The numerical experiments explore the dependence of this process on such factors as ratio of convergent versus strike-slip motion at the plate boundary, and rheological parameters of crust and mantle. The behaviour of the crust is also tracked to determine how the deep 3D tectonics may manifest at the surface.

  13. Computationally efficient perturbative forward modeling for 3D multispectral bioluminescence and fluorescence tomography

    Dutta, Joyita; Ahn, Sangtae; Li, Changqing; Chaudhari, Abhijit J.; Cherry, Simon R.; Leahy, Richard M.

    2008-03-01

    The forward problem of optical bioluminescence and fluorescence tomography seeks to determine, for a given 3D source distribution, the photon density on the surface of an animal. Photon transport through tissues is commonly modeled by the diffusion equation. The challenge, then, is to accurately and efficiently solve the diffusion equation for a realistic animal geometry and heterogeneous tissue types. Fast analytical solvers are available that can be applied to arbitrary geometries but assume homogeneity of tissue optical properties and hence have limited accuracy. The finite element method (FEM) with volume tessellation allows reasonably accurate modeling of both animal geometry and tissue heterogeneity, but this approach is computationally intensive. The computational challenge is heightened when one is working with multispectral data to improve source localization and conditioning of the inverse problem. Here we present a fast forward model based on the Born approximation that falls in between these two approaches. Our model introduces tissue heterogeneity as perturbations in diffusion and absorption coefficients at rectangular grid points inside a mouse atlas. These reflect as a correction term added to the homogeneous forward model. We have tested our model by performing source localization studies first with a biolumnescence simulation setup and then with an experimental setup using a fluorescent source embedded in an inhomogeneous phantom that mimicks tissue optical properties.

  14. Parallel computing simulation of electrical excitation and conduction in the 3D human heart.

    Di Yu; Dongping Du; Hui Yang; Yicheng Tu

    2014-01-01

    A correctly beating heart is important to ensure adequate circulation of blood throughout the body. Normal heart rhythm is produced by the orchestrated conduction of electrical signals throughout the heart. Cardiac electrical activity is the resulted function of a series of complex biochemical-mechanical reactions, which involves transportation and bio-distribution of ionic flows through a variety of biological ion channels. Cardiac arrhythmias are caused by the direct alteration of ion channel activity that results in changes in the AP waveform. In this work, we developed a whole-heart simulation model with the use of massive parallel computing with GPGPU and OpenGL. The simulation algorithm was implemented under several different versions for the purpose of comparisons, including one conventional CPU version and two GPU versions based on Nvidia CUDA platform. OpenGL was utilized for the visualization / interaction platform because it is open source, light weight and universally supported by various operating systems. The experimental results show that the GPU-based simulation outperforms the conventional CPU-based approach and significantly improves the speed of simulation. By adopting modern computer architecture, this present investigation enables real-time simulation and visualization of electrical excitation and conduction in the large and complicated 3D geometry of a real-world human heart.

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

    Agulleiro, J.I.; Vazquez, F.; Garzon, E.M. [Supercomputing and Algorithms Group, Associated Unit CSIC-UAL, University of Almeria, 04120 Almeria (Spain); Fernandez, J.J., E-mail: JJ.Fernandez@csic.es [National Centre for Biotechnology, National Research Council (CNB-CSIC), Campus UAM, C/Darwin 3, Cantoblanco, 28049 Madrid (Spain)

    2012-04-15

    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. -- Highlights: Black-Right-Pointing-Pointer Hybrid computing allows full exploitation of the power (CPU+GPU) in a computer. Black-Right-Pointing-Pointer Proper orchestration of workload is managed by an on-demand strategy. Black-Right-Pointing-Pointer Total number of threads running in the system should be limited to the number of CPUs.

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

    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 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.

  17. Computer-assisted diagnostic system for neurodegenerative dementia using brain SPECT and 3D-SSP

    Ishii, Kazunari; Kanda, Tomonori; Uemura, Takafumi; Miyamoto, Naokazu; Yoshikawa, Toshiki [Hyogo Brain and Heart Center, Department of Radiology and Nuclear Medicine, Himeji, Hyogo (Japan); Shimada, Kenichi; Ohkawa, Shingo [Hyogo Brain and Heart Center, Institute for Aging Brain and Cognitive Disorders, Himeji, Hyogo (Japan); Minoshima, Satoshi [University of Washington, Radiology and Bioengineering, Department of Radiology, Seattle, WA (United States)

    2009-05-15

    To develop a computer-assisted automated diagnostic system to distinguish among Alzheimer disease (AD), dementia with Lewy bodies (DLB), and other degenerative disorders in patients with mild dementia. Single photon emission computed tomography (SPECT) images with injection of N-Isopropyl-p-[{sup 123}I]iodoamphetamine (IMP) were obtained from patients with mild degenerative dementia. First, datasets from 20 patients mild AD, 15 patients with dementia with DLB, and 17 healthy controls were used to develop an automated diagnosing system based on three-dimensional stereotactic surface projections (3D-SSP). AD- and DLB-specific regional templates were created using 3D-SSP, and critical Z scores in the templates were established. Datasets from 50 AD patients, 8 DLB patients, and 10 patients with non-AD/DLB type degenerative dementia (5 with frontotemporal dementia and 5 with progressive supranuclear palsy) were then used to test the diagnostic accuracy of the optimized automated system in comparison to the diagnostic interpretation of conventional IMP-SPECT images. These comparisons were performed to differentiate AD and DLB from non-AD/DLB and to distinguish AD from DLB. A receiver operating characteristic (ROC) analysis was performed. The area under the ROC curve (Az) and the accuracy of the automated diagnosis system were 0.89 and 82%, respectively, for AD/DLB vs. non-AD/DLB patients, and 0.70 and 65%, respectively, for AD vs. DLB patients. The mean Az and the accuracy of the visual inspection were 0.84 and 77%, respectively, for AD/DLB vs. non-AD/DLB patients, and 0.70 and 65%, respectively, for AD vs. DLB patients. The mean Az and the accuracy of the combination of visual inspection and this system were 0.96 and 91%, respectively, for AD/DLB vs. non-AD/DLB patients, and 0.70 and 66%, respectively, for AD vs. DLB patients. The system developed in the present study achieved as good discrimination of AD, DLB, and other degenerative disorders in patients with mild

  18. 3D printing meets computational astrophysics: deciphering the structure of η Carinae's inner colliding winds

    Madura, T. I.; Clementel, N.; Gull, T. R.; Kruip, C. J. H.; Paardekooper, J.-P.

    2015-06-01

    We present the first 3D prints of output from a supercomputer simulation of a complex astrophysical system, the colliding stellar winds in the massive (≳120 M⊙), highly eccentric (e ˜ 0.9) binary star system η Carinae. We demonstrate the methodology used to incorporate 3D interactive figures into a PDF (Portable Document Format) journal publication and the benefits of using 3D visualization and 3D printing as tools to analyse data from multidimensional numerical simulations. Using a consumer-grade 3D printer (MakerBot Replicator 2X), we successfully printed 3D smoothed particle hydrodynamics simulations of η Carinae's inner (r ˜ 110 au) wind-wind collision interface at multiple orbital phases. The 3D prints and visualizations reveal important, previously unknown `finger-like' structures at orbital phases shortly after periastron (φ ˜ 1.045) that protrude radially outwards from the spiral wind-wind collision region. We speculate that these fingers are related to instabilities (e.g. thin-shell, Rayleigh-Taylor) that arise at the interface between the radiatively cooled layer of dense post-shock primary-star wind and the fast (3000 km s-1), adiabatic post-shock companion-star wind. The success of our work and easy identification of previously unrecognized physical features highlight the important role 3D printing and interactive graphics can play in the visualization and understanding of complex 3D time-dependent numerical simulations of astrophysical phenomena.

  19. A new approach of building 3D visualization framework for multimodal medical images display and computed assisted diagnosis

    Li, Zhenwei; Sun, Jianyong; Zhang, Jianguo

    2012-02-01

    As more and more CT/MR studies are scanning with larger volume of data sets, more and more radiologists and clinician would like using PACS WS to display and manipulate these larger data sets of images with 3D rendering features. In this paper, we proposed a design method and implantation strategy to develop 3D image display component not only with normal 3D display functions but also with multi-modal medical image fusion as well as compute-assisted diagnosis of coronary heart diseases. The 3D component has been integrated into the PACS display workstation of Shanghai Huadong Hospital, and the clinical practice showed that it is easy for radiologists and physicians to use these 3D functions such as multi-modalities' (e.g. CT, MRI, PET, SPECT) visualization, registration and fusion, and the lesion quantitative measurements. The users were satisfying with the rendering speeds and quality of 3D reconstruction. The advantages of the component include low requirements for computer hardware, easy integration, reliable performance and comfortable application experience. With this system, the radiologists and the clinicians can manipulate with 3D images easily, and use the advanced visualization tools to facilitate their work with a PACS display workstation at any time.

  20. 一种三维物体相息图的迭代计算方法%An Iterative Algorithm for Kinoform Computation of 3D Object

    裴闯; 蒋晓瑜; 王加; 张鹏炜

    2013-01-01

    在传统迭代傅里叶变换算法的基础上,提出了一种计算三维物体相息图的新方法.基于层析法将三维物体的多个分层物面作为衍射再现图像,在一个输入面(相息图)和多个输出面(再现像)之间进行迭代.通过在傅里叶迭代运算中引入距离相位因子,表示物体不同物面的深度,体现了物体的三维特征.实验结果证明了本文算法良好的收敛特性和再现性能.最后,分析了物面数量和间距对全息再现质量的影响,利用液晶空间光调制器采用时分复用的方法还原了三维物体的多个物面.%A novel method for computing kinoform of 3D object based on traditional iterative Fourier transform algorithm is described. The method divides three-dimensional object into many object planes by tomographic technique and treat every object plane as a target image, then iterative computation is carried out between one input plane(kinoform) and several output planes (reconstruction images). A space phase factor is added into iterative process to represent depth characters of 3D object. The experimental result shows that this algorithm computational and convergent velocity is fast. At last, the influences of object planes number and distance to reconstruction quality of kinoform are analyzed, and time-division multiplexing technique is used to reconstruct several object planes based on spatial light modulator.

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

    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. Computed Tomography 3-D Imaging of the Metal Deformation Flow Path in Friction Stir Welding

    Schneider, Judy; Beshears, Ronald; Nunes, Arthur C., Jr.

    2005-01-01

    In friction stir welding (FSW), a rotating threaded pin tool is inserted into a weld seam and literally stirs the edges of the seam together. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path is required. Marker studies are the principal method of studying the metal deformation flow path around the FSW pin tool. In our study, we have used computed tomography (CT) scans to reveal the flow pattern of a lead wire embedded in a FSW weld seam. At the welding temperature of aluminum, the lead becomes molten and is carried with the macro-flow of the weld metal. By using CT images, a 3-dimensional (3D) image of the lead flow pattern can be reconstructed. CT imaging was found to be a convenient and comprehensive way of collecting and displaying tracer data. It marks an advance over previous more tedious and ambiguous radiographic/metallographic data collection methods.

  3. Study of strength properties of ceramic composites with soft filler based on 3D computer simulation

    Smolin, Alexey Yu.; Smolin, Igor Yu.; Smolina, Irina Yu.

    2016-11-01

    The movable cellular automaton method which is a computational method of particle mechanics is applied to simulating uniaxial compression of 3D specimens of a ceramic composite. Soft inclusions were considered explicitly by changing the sort (properties) of automata selected randomly from the original fcc packing. The distribution of inclusions in space, their size, and the total fraction were varied. For each value of inclusion fraction, there were generated several representative specimens with individual pore position in space. The resulting magnitudes of the elastic modulus and strength of the specimens were scattered and well described by the Weibull distribution. We showed that to reveal the dependence of the elastic and strength properties of the composite on the inclusion fraction it is much better to consider the mathematical expectation of the corresponding Weibull distribution, rather than the average of the values for the specimens of the same inclusion fraction. It is shown that the relation between the mechanical properties of material and its inclusion fraction depends significantly on the material structure. Namely, percolation transition from isolated inclusions to interconnected clusters of inclusions strongly manifests itself in the dependence of strength on the fraction of inclusions. Thus, the curve of strength versus inclusion fraction fits different equations for a different kind of structure.

  4. Computer-assisted 3D kinematic analysis of all leg joints in walking insects.

    John A Bender

    Full Text Available High-speed video can provide fine-scaled analysis of animal behavior. However, extracting behavioral data from video sequences is a time-consuming, tedious, subjective task. These issues are exacerbated where accurate behavioral descriptions require analysis of multiple points in three dimensions. We describe a new computer program written to assist a user in simultaneously extracting three-dimensional kinematics of multiple points on each of an insect's six legs. Digital video of a walking cockroach was collected in grayscale at 500 fps from two synchronized, calibrated cameras. We improved the legs' visibility by painting white dots on the joints, similar to techniques used for digitizing human motion. Compared to manual digitization of 26 points on the legs over a single, 8-second bout of walking (or 106,496 individual 3D points, our software achieved approximately 90% of the accuracy with 10% of the labor. Our experimental design reduced the complexity of the tracking problem by tethering the insect and allowing it to walk in place on a lightly oiled glass surface, but in principle, the algorithms implemented are extensible to free walking. Our software is free and open-source, written in the free language Python and including a graphical user interface for configuration and control. We encourage collaborative enhancements to make this tool both better and widely utilized.

  5. GBM Volumetry using the 3D Slicer Medical Image Computing Platform

    Egger, Jan; Kapur, Tina; Fedorov, Andriy; Pieper, Steve; Miller, James V.; Veeraraghavan, Harini; Freisleben, Bernd; Golby, Alexandra J.; Nimsky, Christopher; Kikinis, Ron

    2013-01-01

    Volumetric change in glioblastoma multiforme (GBM) over time is a critical factor in treatment decisions. Typically, the tumor volume is computed on a slice-by-slice basis using MRI scans obtained at regular intervals. (3D)Slicer – a free platform for biomedical research – provides an alternative to this manual slice-by-slice segmentation process, which is significantly faster and requires less user interaction. In this study, 4 physicians segmented GBMs in 10 patients, once using the competitive region-growing based GrowCut segmentation module of Slicer, and once purely by drawing boundaries completely manually on a slice-by-slice basis. Furthermore, we provide a variability analysis for three physicians for 12 GBMs. The time required for GrowCut segmentation was on an average 61% of the time required for a pure manual segmentation. A comparison of Slicer-based segmentation with manual slice-by-slice segmentation resulted in a Dice Similarity Coefficient of 88.43 ± 5.23% and a Hausdorff Distance of 2.32 ± 5.23 mm. PMID:23455483

  6. Superresolution of 3-D computational integral imaging based on moving least square method.

    Kim, Hyein; Lee, Sukho; Ryu, Taekyung; Yoon, Jungho

    2014-11-17

    In this paper, we propose an edge directive moving least square (ED-MLS) based superresolution method for computational integral imaging reconstruction(CIIR). Due to the low resolution of the elemental images and the alignment error of the microlenses, it is not easy to obtain an accurate registration result in integral imaging, which makes it difficult to apply superresolution to the CIIR application. To overcome this problem, we propose the edge directive moving least square (ED-MLS) based superresolution method which utilizes the properties of the moving least square. The proposed ED-MLS based superresolution takes the direction of the edge into account in the moving least square reconstruction to deal with the abrupt brightness changes in the edge regions, and is less sensitive to the registration error. Furthermore, we propose a framework which shows how the data have to be collected for the superresolution problem in the CIIR application. Experimental results verify that the resolution of the elemental images is enhanced, and that a high resolution reconstructed 3-D image can be obtained with the proposed method.

  7. Performance Assessment of Three Rendering Engines in 3D Computer Graphics Software

    Žan Vidmar

    2015-03-01

    Full Text Available The aim of the research was the determination of testing conditions and visual and numerical evaluation of renderings made with three different rendering engines in Maya software, which is widely used for educational and computer art purposes. In the theoretical part the overview of light phenomena and their simulation in virtual space is presented. This is followed by a detailed presentation of the main rendering methods and the results and limitations of their applications to 3D objects. At the end of the theoretical part the importance of a proper testing scene and especially the role of Cornell box are explained. In the experimental part the terms and conditions as well as hardware and software used for the research are presented. This is followed by a description of the procedures, where we focused on the rendering quality and time, which enabled the comparison of settings of different render engines and determination of conditions for further rendering of testing scenes. The experimental part continued with rendering a variety of simple virtual scenes including Cornell box and virtual object with different materials and colours. Apart from visual evaluation, which was the starting point for comparison of renderings, a procedure for numerical estimation and colour deviations of renderings using the selected regions of interest in the final images is presented.

  8. Detectability of hepatic tumors during 3D post-processed ultrafast cone-beam computed tomography

    Paul, Jijo; Vogl, Thomas J.; Chacko, Annamma

    2015-10-01

    To evaluate hepatic tumor detection using ultrafast cone-beam computed tomography (UCBCT) cross-sectional and 3D post-processed image datasets. 657 patients were examined using UCBCT during hepatic transarterial chemoembolization (TACE), and data were collected retrospectively from January 2012 to September 2014. Tumor detectability, diagnostic ability, detection accuracy and sensitivity were examined for different hepatic tumors using UCBCT cross-sectional, perfusion blood volume (PBV) and UCBCT-MRI (magnetic resonance imaging) fused image datasets. Appropriate statistical tests were used to compare collected sample data. Fused image data showed the significantly higher (all P  color display. Fused image data produced 100% tumor sensitivity due to the simultaneous availability of MRI and UCBCT information during tumor diagnosis. Fused image data produced excellent hepatic tumor sensitivity, detectability and diagnostic ability compared to other datasets assessed. Fused image data is extremely reliable and useful compared to UCBCT cross-sectional or PBV image datasets to depict hepatic tumors during TACE. Partial anatomical visualization on cross-sectional images was compensated by fused image data during tumor diagnosis.

  9. Non-Hodgkin lymphoma: computed tomographic demonstration of unusual extranodal involvement

    Glazer, H.S.; Lee, J.K.T.; Balfe, D.M.; Mauro, M.A.; Griffith, R.; Sagel, S.S.

    1983-10-01

    With the advent of computed tomography, lymphomatous involvement of sites other than lymph nodes is being seen with increasing frequency. Review of computed tomographic scans in 400 patients with newly diagnosed or recurrent non-Hodgkin lymphoma revealed 37 patients to have involvement of 56 unusual sites below the diaphragm: psoas/iliacus muscle (16 patients), kidney (13 patients), pancreas (5 patients), adrenal (4 patients), skin/subcutaneous tissue (4 patients), abdominal wall musculature (4 patients), peritoneum (4 patients), omentum (3 patients), and female reproductive tract (3 patients). These were mostly seen in patients with lymphomas of diffuse architecture, especially diffuse histiocytic lymphoma. Concomitant retroperitoneal and/or mesenteric adenopathy was very common; extraodal involvement was rarely the only site of initial or recurrent lymphoma.

  10. Non-Hodgkin lymphoma: computed tomographic demonstration of unusual extranodal involvement.

    Glazer, H S; Lee, J K; Balfe, D M; Mauro, M A; Griffith, R; Sagel, S S

    1983-10-01

    With the advent of computed tomography, lymphomatous involvement of sites other than lymph nodes is being seen with increasing frequency. Review of computed tomographic scans in 400 patients with newly diagnosed or recurrent non-Hodgkin lymphoma revealed 37 patients to have involvement of 56 unusual sites below the diaphragm: psoas/iliacus muscle (16 patients), kidney (13 patients), pancreas (5 patients), adrenal (4 patients), skin/subcutaneous tissue (4 patients), abdominal wall musculature (4 patients), peritoneum (4 patients), omentum (3 patients), and female reproductive tract (3 patients). These were mostly seen in patients with lymphomas of diffuse architecture, especially diffuse histiocytic lymphoma. Concomitant retroperitoneal and/or mesenteric adenopathy was very common; extranodal involvement was rarely the only site of initial or recurrent lymphoma.

  11. Microwave Tomographic Imaging of Cerebrovascular Accidents by Using High-Performance Computing

    Tournier, P -H; Bonazzoli, M; de Buhan, M; Darbas, M; Dolean, V; Hecht, F; Jolivet, P; Kanfoud, I El; Migliaccio, C; Nataf, F; Pichot, C; Semenov, S

    2016-01-01

    The motivation of this work is the detection of cerebrovascular accidents by microwave tomographic imaging. This requires the solution of an inverse problem relying on a minimization algorithm (for example, gradient-based), where successive iterations consist in repeated solutions of a direct problem. The reconstruction algorithm is extremely computationally intensive and makes use of efficient parallel algorithms and high-performance computing. The feasibility of this type of imaging is conditioned on one hand by an accurate reconstruction of the material properties of the propagation medium and on the other hand by a considerable reduction in simulation time. Fulfilling these two requirements will enable a very rapid and accurate diagnosis. From the mathematical and numerical point of view, this means solving Maxwell's equations in time-harmonic regime by appropriate domain decomposition methods, which are naturally adapted to parallel architectures.

  12. Construction of computer tomographic phantoms and their application in radiology and radiation protection

    Zankl, M.; Veit, R.; Williams, G.; Schneider, K.; Fendel, H.; Petoussi, N.; Drexler, G.

    1988-05-01

    In order to assess human organ doses for risk estimates under natural and man made radiation exposure conditions, human phantoms have to be used. As an improvement to the mathematical anthropomorphic phantoms, a new family of phantoms is proposed, constructed from Computer Tomographic (CT) data. A technique is developed which allows any physical phantom to be converted into computer files to be used for several applications. The new human phantoms present advantages towards the location and shape of the organs, in particular the hard bone and bone marrow. The CT phantoms were used to construct three dimensional images of high resolution; some examples are given and their potential is discussed. The use of CT phantoms is also demonstrated to assess accurately the proportion of bone marrow in the skeleton. Finally, the use of CT phantoms for Monte Carlo (MC) calculations of doses resulting from various photon exposures in radiology and radiation protection is discussed.

  13. Algorithms for Fast Computing of the 3D-DCT Transform

    S. Hanus

    2003-04-01

    Full Text Available The algorithm for video compression based on the Three-DimensionalDiscrete Cosine Transform (3D-DCT is presented. The original algorithmof the 3D-DCT has high time complexity. We propose several enhancementsto the original algorithm and make the calculation of the DCT algorithmfeasible for future real-time video compression.

  14. 3D Printing Meets Computational Astrophysics: Deciphering the Structure of Eta Carinae's Inner Colliding Winds

    Madura, Thomas I; Gull, Theodore R; Kruip, Chael J H; Paardekooper, Jan-Pieter

    2015-01-01

    We present the first 3D prints of output from a supercomputer simulation of a complex astrophysical system, the colliding stellar winds in the massive (>120 M_Sun), highly eccentric (e ~ 0.9) binary star system Eta Carinae. We demonstrate the methodology used to incorporate 3D interactive figures into a PDF journal publication and the benefits of using 3D visualization and 3D printing as tools to analyze data from multidimensional numerical simulations. Using a consumer-grade 3D printer (MakerBot Replicator 2X), we successfully printed 3D smoothed particle hydrodynamics (SPH) simulations of Eta Carinae's inner (r ~ 110 au) wind-wind collision interface at multiple orbital phases. The 3D prints and visualizations reveal important, previously unknown 'finger-like' structures at orbital phases shortly after periastron (phi ~ 1.045) that protrude radially outward from the spiral wind-wind collision region. We speculate that these fingers are related to instabilities (e.g. thin-shell, Rayleigh-Taylor) that arise a...

  15. Lagrangian Finite Element Method for 3D Time-Dependent Viscoelastic Flow Computations using Integral Models

    Rasmussen, Henrik Koblitz

    2000-01-01

    The 3D-LIM has as yet been used to simulate the following two three-dimensional problems. First, the method has been used to simulete for viscoelastic end-plate instability that occurs under certain conditions in the transient filament stretching apparatus for pressure sensitive adhesives...... (polymeric melts) and polymeric solutions. Secondly, the 3D-LIM has also been applied to calculate the inflation of a thick sheet of a polymer melt into an elliptic cylinder. These problems all include free surfaces. As the governing equations are solved for the particle positions, the motion of surfaces can...... be followed easily even in 3D viscoelastic flow....

  16. A new cone-beam computed tomography system for dental applications with innovative 3D software

    Pasini, Alessandro; Bianconi, D.; Rossi, A. [University of Bologna, Department of Physics, Bologna (Italy); NECTAR Imaging srl Imola (Italy); Casali, F. [University of Bologna, Department of Physics, Bologna (Italy); Bontempi, M. [CEFLA Dental Group Imola (Italy)

    2007-02-15

    Objective Cone beam computed tomography (CBCT) is an important image technique for oral surgery (dentoalveolar surgery and dental implantology) and maxillofacial applications. This technique requires compact sized scanners with a relatively low radiation dosage, which makes them suitable for imaging of the craniofacial region. This article aims to present the concept and the preliminary findings obtained with the prototype of a new CBCT scanner with dedicated 3D software, specifically designed for dental imaging. Methods The prototype implements an X-ray tube with a nominal focal spot of 0.5 mm operating at 70-100 kVp and 1-4 mA. The detector is a 6 in. image intensifier coupled with a digital CCD camera. Dosimetry was performed on a RANDO anthropomorphic phantom using Beryllium Oxide thermo-luminescent dosimeters positioned in the phantom in the following site: eyes, thyroid, skin (lips, cheeks, back of the neck), brain, mandible, maxilla and parotid glands. Doses were measured using four configurations, changing the field-of-view (4'' and 6'') and acquisition time (10 and 20 s) of the CBCT. Acquisitions were performed with different parameters regarding the x-ray tube, pixel size and acquisition geometries to evaluate image quality in relation to modulation transfer function (MTF), noise and geometric accuracy. Results The prototype was able to acquire a complete maxillofacial scan in 10-15 s. The CT reconstruction algorithm delivered images that were judged to have high quality, allowing for precise volume rendering. The radiation dose was determined to be 1-1.5 times that of the dose applied during conventional dental panoramic studies. Conclusion Preliminary studies using the CBCT prototype indicate that this device provides images with acceptable diagnostic content at a relatively low radiation dosage, if compared to systems currently available on the market. (orig.)

  17. Computer numerical control (CNC) lithography: light-motion synchronized UV-LED lithography for 3D microfabrication

    Kim, Jungkwun; Yoon, Yong-Kyu; Allen, Mark G.

    2016-03-01

    This paper presents a computer-numerical-controlled ultraviolet light-emitting diode (CNC UV-LED) lithography scheme for three-dimensional (3D) microfabrication. The CNC lithography scheme utilizes sequential multi-angled UV light exposures along with a synchronized switchable UV light source to create arbitrary 3D light traces, which are transferred into the photosensitive resist. The system comprises a switchable, movable UV-LED array as a light source, a motorized tilt-rotational sample holder, and a computer-control unit. System operation is such that the tilt-rotational sample holder moves in a pre-programmed routine, and the UV-LED is illuminated only at desired positions of the sample holder during the desired time period, enabling the formation of complex 3D microstructures. This facilitates easy fabrication of complex 3D structures, which otherwise would have required multiple manual exposure steps as in the previous multidirectional 3D UV lithography approach. Since it is batch processed, processing time is far less than that of the 3D printing approach at the expense of some reduction in the degree of achievable 3D structure complexity. In order to produce uniform light intensity from the arrayed LED light source, the UV-LED array stage has been kept rotating during exposure. UV-LED 3D fabrication capability was demonstrated through a plurality of complex structures such as V-shaped micropillars, micropanels, a micro-‘hi’ structure, a micro-‘cat’s claw,’ a micro-‘horn,’ a micro-‘calla lily,’ a micro-‘cowboy’s hat,’ and a micro-‘table napkin’ array.

  18. Development, Verification and Use of Gust Modeling in the NASA Computational Fluid Dynamics Code FUN3D

    Bartels, Robert E.

    2012-01-01

    This paper presents the implementation of gust modeling capability in the CFD code FUN3D. The gust capability is verified by computing the response of an airfoil to a sharp edged gust. This result is compared with the theoretical result. The present simulations will be compared with other CFD gust simulations. This paper also serves as a users manual for FUN3D gust analyses using a variety of gust profiles. Finally, the development of an Auto-Regressive Moving-Average (ARMA) reduced order gust model using a gust with a Gaussian profile in the FUN3D code is presented. ARMA simulated results of a sequence of one-minus-cosine gusts is shown to compare well with the same gust profile computed with FUN3D. Proper Orthogonal Decomposition (POD) is combined with the ARMA modeling technique to predict the time varying pressure coefficient increment distribution due to a novel gust profile. The aeroelastic response of a pitch/plunge airfoil to a gust environment is computed with a reduced order model, and compared with a direct simulation of the system in the FUN3D code. The two results are found to agree very well.

  19. Ultrasonographic and computed tomographic findings of hemorrhagic cholecystitis; report of two cases

    Kim, Bum Soo; Byun, Jae Young; Shinn, Kyung Sub [Catholic Univ. College of Medicine, Seoul (Korea, Republic of); Kim, Jong Woo [Kangnung Dongin Hospital, Kangnung (Korea, Republic of)

    1996-01-01

    Hemorrhagic cholecystitis(HC) is a rare complication of gallbladder(GB) disease characterized by mucosal and intraluminal hemorrhage of the GB. We report ultrasonographic(US) and computed tomographic(CT) findings of two cases of HC. Hemorrhagic fluid filled in the inflamed GB lumen was initially seen as homogeneous hyperdense and hyperattenuated lesion on both US and CT, respectively. As resolution of the hematoma and gangrenous change of the GB wall progress, US showed inhomogeneous mixed echogenic lesion in the GB having partially indistinct border, mimicking an invasive mass. At this stage, CT still showed homogeneous hyperdense hematoma and a small amount of fluid in the GB, without evidence of contrast enhancement.

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

    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.

  1. CS651 Computer Systems Security Foundations 3d Imagination Cyber Security Management Plan

    Nielsen, Roy S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-02

    3d Imagination is a new company that bases its business on selling and improving 3d open source related hardware. The devices that they sell include 3d imagers, 3d printers, pick and place machines and laser etchers. They have a fast company intranet for ease in sharing, storing and printing large, complex 3d designs. They have an employee set that requires a variety of operating systems including Windows, Mac and a variety of Linux both for running business services as well as design and test machines. There are a wide variety of private networks for testing transfer rates to and from the 3d devices, without interference with other network tra c. They do video conferencing conferencing with customers and other designers. One of their machines is based on the project found at delta.firepick.org(Krassenstein, 2014; Biggs, 2014), which in future, will perform most of those functions. Their devices all include embedded systems, that may have full blown operating systems. Most of their systems are designed to have swappable parts, so when a new technology is born, it can be quickly adopted by people with 3d Imagination hardware. This company is producing a fair number of systems and components, however to get the funding they need to mass produce quality parts, so they are preparing for an IPO to raise the funds they need. They would like to have a cyber-security audit performed so they can give their investors con dence that they are protecting their data, customers information and printers in a proactive manner.

  2. Comparative validity and reproducibility study of various landmark-oriented reference planes in 3-dimensional computed tomographic analysis for patients receiving orthognathic surgery.

    Hsiu-Hsia Lin

    Full Text Available 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.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.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.The 5 horizontal reference planes were

  3. 3D Nondestructive Visualization and Evaluation of TRISO Particles Distribution in HTGR Fuel Pebbles Using Cone-Beam Computed Tomography

    Gongyi Yu

    2017-01-01

    Full Text Available A nonuniform distribution of tristructural isotropic (TRISO particles within a high-temperature gas-cooled reactor (HTGR pebble may lead to excessive thermal gradients and nonuniform thermal expansion during operation. If the particles are closely clustered, local hotspots may form, leading to excessive stresses on particle layers and an increased probability of particle failure. Although X-ray digital radiography (DR is currently used to evaluate the TRISO distributions in pebbles, X-ray DR projection images are two-dimensional in nature, which would potentially miss some details for 3D evaluation. This paper proposes a method of 3D visualization and evaluation of the TRISO distribution in HTGR pebbles using cone-beam computed tomography (CBCT: first, a pebble is scanned on our high-resolution CBCT, and 2D cross-sectional images are reconstructed; secondly, all cross-sectional images are restructured to form the 3D model of the pebble; then, volume rendering is applied to segment and display the TRISO particles in 3D for visualization and distribution evaluation. For method validation, several pebbles were scanned and the 3D distributions of the TRISO particles within the pebbles were produced. Experiment results show that the proposed method provides more 3D than DR, which will facilitate pebble fabrication research and production quality control.

  4. Error propagation in the computation of volumes in 3D city models with the Monte Carlo method

    Biljecki, F.; Ledoux, H.; Stoter, J.

    2014-01-01

    This paper describes the analysis of the propagation of positional uncertainty in 3D city models to the uncertainty in the computation of their volumes. Current work related to error propagation in GIS is limited to 2D data and 2D GIS operations, especially of rasters. In this research we have (1) d

  5. A collaborative computing framework of cloud network and WBSN applied to fall detection and 3-D motion reconstruction.

    Lai, Chin-Feng; Chen, Min; Pan, Jeng-Shyang; Youn, Chan-Hyun; Chao, Han-Chieh

    2014-03-01

    As cloud computing and wireless body sensor network technologies become gradually developed, ubiquitous healthcare services prevent accidents instantly and effectively, as well as provides relevant information to reduce related processing time and cost. This study proposes a co-processing intermediary framework integrated cloud and wireless body sensor networks, which is mainly applied to fall detection and 3-D motion reconstruction. In this study, the main focuses includes distributed computing and resource allocation of processing sensing data over the computing architecture, network conditions and performance evaluation. Through this framework, the transmissions and computing time of sensing data are reduced to enhance overall performance for the services of fall events detection and 3-D motion reconstruction.

  6. Evaluation of the durability of 3D printed keys produced by computational processing of image data

    Straub, Jeremy; Kerlin, Scott

    2016-05-01

    Possession of a working 3D printed key can, for most practical purposes, convince observers that an illicit attempt to gain premises access is authorized. This paper seeks to assess three things. First, work has been performed to determine how easily the data for making models of keys can be obtained through manual measurement. It then presents work done to create a model of the key and determine how easy key modeling could be (particularly after a first key of a given key `blank' has been made). Finally, it seeks to assess the durability of the keys produced using 3D printing.

  7. Computational Graph Model for 3D Cells Tracking in Zebra Fish Datasets

    Zhang, Lelin; Xiong, Hongkai; Zhao, Yang; Zhang, Kai; Zhou, Xiaobo

    2007-11-01

    This paper leads to a novel technique for tracking and identification of zebra-fish cells in 3D image sequences, extending graph-based multi-objects tracking algorithm to 3D applications. As raised in previous work of 2D graph-based method, separated cells are modeled as vertices that connected by edges. Then the tracking work is simplified to that of vertices matching between graphs generated from consecutive frames. Graph-based tracking is composed of three steps: graph generation, initial source vertices selection and graph saturation. To satisfy demands in this work separated cell records are segmented from original datasets using 3D level-set algorithms. Besides, advancements are achieved in each of the step including graph regulations, multi restrictions on source vertices and enhanced flow quantifications. Those strategies make a good compensation for graph-based multi-objects tracking method in 2D space. Experiments are carried out in 3D datasets sampled from zebra fish, results of which shows that this enhanced method could be potentially applied to tracking of objects with diverse features.

  8. Fatigue of multiscale composites with secondary nanoplatelet reinforcement: 3D computational analysis

    Dai, Gaoming; Mishnaevsky, Leon, Jr.

    2014-01-01

    3D numerical simulations of fatigue damage of multiscale fiber reinforced polymer composites with secondary nanoclay reinforcement are carried out. Macro–micro FE models of the multiscale composites are generated automatically using Python based software. The effect of the nanoclay reinforcement...

  9. 3D Printing Meets Computational Astrophysics: Deciphering the Structure of Eta Carinae’s Colliding Winds Using 3D Prints of Smoothed Particle Hydrodynamics Simulations

    Madura, Thomas; Gull, Theodore R.; Clementel, Nicola; Paardekooper, Jan-Pieter; Kruip, Chael; Corcoran, Michael F.; Hamaguchi, Kenji; Teodoro, Mairan

    2015-01-01

    We present the first 3D prints of output from a supercomputer simulation of a complex astrophysical system, the colliding stellar winds in the massive (>120 MSun), highly eccentric (e ~ 0.9) binary Eta Carinae. Using a consumer-grade 3D printer (Makerbot Replicator 2X), we successfully printed 3D smoothed particle hydrodynamics simulations of Eta Carinae's inner (r ~110 AU) wind-wind collision interface at multiple orbital phases. These 3D prints reveal important, previously unknown 'finger-like' structures at orbital phases shortly after periastron (φ ~1.045) that protrude radially outward from the spiral wind-wind collision region. We speculate that these fingers are related to instabilities (e.g. Rayleigh-Taylor) that arise at the interface between the radiatively-cooled layer of dense post-shock primary-star wind and the hot, adiabatic post-shock companion-star wind. The success of our work and easy identification of previously unknown physical features highlight the important role 3D printing can play in the visualization and understanding of complex 3D time-dependent numerical simulations of astrophysical phenomena.

  10. Computer system to manage information rigs by 3D electronic models; Sistema computacional para administrar la informacion de plataformas petroleras mediante modelos electronicos 3D

    Vazquez Bustos, Jesus; Segura Ozuna, Victor Octavio [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2012-06-22

    The evolution and incorporation of new hardware technologies, as well as recent advances in computer systems have enabled the development of applications of computer aided design of most complete scope, such as those used for the design of industrial process plants. This article describes a software system developed to complement the capabilities of one of these systems for the design of process plants. A 3D electronic model is generated through the user interface of the design system that at the same time gives the user the ability to generate, publish, review and control the engineering document that are generated during the entire life cycle of a marine oil platform, a very particular type of industrial process plant. This way, the user obtains not only a tool for the design of an industrial plant, but also a system for managing information and engineering documents that are developed. This allows the user to do a more efficient job by putting at his disposal and in the same system, all documents and information required to perform his duty. [Spanish] La evolucion e incorporacion de nuevas tecnologias de hardware, junto con los avances recientes en sistemas de computo ha permitido el desarrollo de aplicaciones de interesante diseno de computo de mayor alcance, tales como los que se emplean en las plantas de procesos industriales. Este articulo describe un sistema de software desarrollado para complementar las capacidades de uno de estos sistemas para el diseno de proceso. Un modelo electronico se genera por medio de la interfaz de usuario del sistema de diseno, que al mismo tiempo da al usuario la capacidad para crear, publicar, revisar y controlar los documentos de ingenieria que se producen durante el ciclo de vida completo de una plataforma marina petrolera, un tipo muy particular de planta de proceso industrial. De este modo, el usuario no solo obtiene una herramienta para el diseno de una planta industrial, sino tambien un sistema para manejar informacion y

  11. Generating 3D anatomically detailed models of the retina from OCT data sets: implications for computational modelling

    Shalbaf, Farzaneh; Dokos, Socrates; Lovell, Nigel H.; Turuwhenua, Jason; Vaghefi, Ehsan

    2015-12-01

    Retinal prosthesis has been proposed to restore vision for those suffering from the retinal pathologies that mainly affect the photoreceptors layer but keep the inner retina intact. Prior to costly risky experimental studies computational modelling of the retina will help to optimize the device parameters and enhance the outcomes. Here, we developed an anatomically detailed computational model of the retina based on OCT data sets. The consecutive OCT images of individual were subsequently segmented to provide a 3D representation of retina in the form of finite elements. Thereafter, the electrical properties of the retina were modelled by implementing partial differential equation on the 3D mesh. Different electrode configurations, that is bipolar and hexapolar configurations, were implemented and the results were compared with the previous computational and experimental studies. Furthermore, the possible effects of the curvature of retinal layers on the current steering through the retina were proposed and linked to the clinical observations.

  12. Computer-aided multiple-head 3D printing system for printing of heterogeneous organ/tissue constructs

    Jung, Jin Woo; Lee, Jung-Seob; Cho, Dong-Woo

    2016-02-01

    Recently, much attention has focused on replacement or/and enhancement of biological tissues via the use of cell-laden hydrogel scaffolds with an architecture that mimics the tissue matrix, and with the desired three-dimensional (3D) external geometry. However, mimicking the heterogeneous tissues that most organs and tissues are formed of is challenging. Although multiple-head 3D printing systems have been proposed for fabricating heterogeneous cell-laden hydrogel scaffolds, to date only the simple exterior form has been realized. Here we describe a computer-aided design and manufacturing (CAD/CAM) system for this application. We aim to develop an algorithm to enable easy, intuitive design and fabrication of a heterogeneous cell-laden hydrogel scaffolds with a free-form 3D geometry. The printing paths of the scaffold are automatically generated from the 3D CAD model, and the scaffold is then printed by dispensing four materials; i.e., a frame, two kinds of cell-laden hydrogel and a support. We demonstrated printing of heterogeneous tissue models formed of hydrogel scaffolds using this approach, including the outer ear, kidney and tooth tissue. These results indicate that this approach is particularly promising for tissue engineering and 3D printing applications to regenerate heterogeneous organs and tissues with tailored geometries to treat specific defects or injuries.

  13. Computer-aided multiple-head 3D printing system for printing of heterogeneous organ/tissue constructs.

    Jung, Jin Woo; Lee, Jung-Seob; Cho, Dong-Woo

    2016-02-22

    Recently, much attention has focused on replacement or/and enhancement of biological tissues via the use of cell-laden hydrogel scaffolds with an architecture that mimics the tissue matrix, and with the desired three-dimensional (3D) external geometry. However, mimicking the heterogeneous tissues that most organs and tissues are formed of is challenging. Although multiple-head 3D printing systems have been proposed for fabricating heterogeneous cell-laden hydrogel scaffolds, to date only the simple exterior form has been realized. Here we describe a computer-aided design and manufacturing (CAD/CAM) system for this application. We aim to develop an algorithm to enable easy, intuitive design and fabrication of a heterogeneous cell-laden hydrogel scaffolds with a free-form 3D geometry. The printing paths of the scaffold are automatically generated from the 3D CAD model, and the scaffold is then printed by dispensing four materials; i.e., a frame, two kinds of cell-laden hydrogel and a support. We demonstrated printing of heterogeneous tissue models formed of hydrogel scaffolds using this approach, including the outer ear, kidney and tooth tissue. These results indicate that this approach is particularly promising for tissue engineering and 3D printing applications to regenerate heterogeneous organs and tissues with tailored geometries to treat specific defects or injuries.

  14. Identification and classification in le fort type fractures by using 2D and 3D computed tomography

    CHEN We-jian; YANG Yun-jun; FANG Yi-ming; XU Fang-hong; ZHANG Lin; CAO Guo-quan

    2006-01-01

    Objective:To evaluate the usefulness of twodimensional (2D) and three-dimensional (3D) computed tomography (CT) in the identification and classification of Le Fort type fractures.Methods: Sixty-two patients with different types of Le Fort fractures underwent CT scanning and 3D-CT reconstruction. The data were analyzed by multiplanar reconstruction (MPR), surface shaded display (SSD) and volume rendering (VR) respectively.Results: The patients with Le Fort Ⅰ , Le Fort Ⅱfracture and Le Fort Ⅲ fracture accounted for 16.1%,14.5 % and 12.9 % respectively. The compound fractures were the most common type and accounted for 56.5 % ( n =35, 18 cases with Le Fort Ⅰ + Ⅱ fracture, 10 cases with Le Fort Ⅱ + Ⅲ fracture and 7 cases with Le Fort Ⅰ + Ⅱ + Ⅲfracture). Fifty-five cases coexisted with other fractures in maxillofacial region. 2D-CT could be used to define the tiny fractures and the deep-structure fractures more accurately compared with 3D-CT, but the real impression of Le Fort type fractures could not be correctly evaluated on 2D-CT.3D-CT could clearly demonstrate the whole shape of Le Fort type fractures and identify the classification of Le Fort fractures.Conclusions: 3D-CT is the best imaging method for the diagnosis of Le Fort type fractures and can provide valuable information of space relationship, especially for the design of treatment plan before operation.

  15. Use of micro computed-tomography and 3D printing for reverse engineering of mouse embryo nasal capsule

    Tesařová, M.; Zikmund, T.; Kaucká, M.; Adameyko, I.; Jaroš, J.; Paloušek, D.; Škaroupka, D.; Kaiser, J.

    2016-03-01

    Imaging of increasingly complex cartilage in vertebrate embryos is one of the key tasks of developmental biology. This is especially important to study shape-organizing processes during initial skeletal formation and growth. Advanced imaging techniques that are reflecting biological needs give a powerful impulse to push the boundaries of biological visualization. Recently, techniques for contrasting tissues and organs have improved considerably, extending traditional 2D imaging approaches to 3D . X-ray micro computed tomography (μCT), which allows 3D imaging of biological objects including their internal structures with a resolution in the micrometer range, in combination with contrasting techniques seems to be the most suitable approach for non-destructive imaging of embryonic developing cartilage. Despite there are many software-based ways for visualization of 3D data sets, having a real solid model of the studied object might give novel opportunities to fully understand the shape-organizing processes in the developing body. In this feasibility study we demonstrated the full procedure of creating a real 3D object of mouse embryo nasal capsule, i.e. the staining, the μCT scanning combined by the advanced data processing and the 3D printing.

  16. High resolution 3-D wavelength diversity imaging

    Farhat, N. H.

    1981-09-01

    A physical optics, vector formulation of microwave imaging of perfectly conducting objects by wavelength and polarization diversity is presented. The results provide the theoretical basis for optimal data acquisition and three-dimensional tomographic image retrieval procedures. These include: (a) the selection of highly thinned (sparse) receiving array arrangements capable of collecting large amounts of information about remote scattering objects in a cost effective manner and (b) techniques for 3-D tomographic image reconstruction and display in which polarization diversity data is fully accounted for. Data acquisition employing a highly attractive AMTDR (Amplitude Modulated Target Derived Reference) technique is discussed and demonstrated by computer simulation. Equipment configuration for the implementation of the AMTDR technique is also given together with a measurement configuration for the implementation of wavelength diversity imaging in a roof experiment aimed at imaging a passing aircraft. Extension of the theory presented to 3-D tomographic imaging of passive noise emitting objects by spectrally selective far field cross-correlation measurements is also given. Finally several refinements made in our anechoic-chamber measurement system are shown to yield drastic improvement in performance and retrieved image quality.

  17. Computer-aided diagnosis for osteoporosis using chest 3D CT images

    Yoneda, K.; Matsuhiro, M.; Suzuki, H.; Kawata, Y.; Niki, N.; Nakano, Y.; Ohmatsu, H.; Kusumoto, M.; Tsuchida, T.; Eguchi, K.; Kaneko, M.

    2016-03-01

    The patients of osteoporosis comprised of about 13 million people in Japan and it is one of the problems the aging society has. In order to prevent the osteoporosis, it is necessary to do early detection and treatment. Multi-slice CT technology has been improving the three dimensional (3-D) image analysis with higher body axis resolution and shorter scan time. The 3-D image analysis using multi-slice CT images of thoracic vertebra can be used as a support to diagnose osteoporosis and at the same time can be used for lung cancer diagnosis which may lead to early detection. We develop automatic extraction and partitioning algorithm for spinal column by analyzing vertebral body structure, and the analysis algorithm of the vertebral body using shape analysis and a bone density measurement for the diagnosis of osteoporosis. Osteoporosis diagnosis support system obtained high extraction rate of the thoracic vertebral in both normal and low doses.

  18. A Pipeline for 3D Multimodality Image Integration and Computer-assisted Planning in Epilepsy Surgery.

    Nowell, Mark; Rodionov, Roman; Zombori, Gergely; Sparks, Rachel; Rizzi, Michele; Ourselin, Sebastien; Miserocchi, Anna; McEvoy, Andrew; Duncan, John

    2016-01-01

    Epilepsy surgery is challenging and the use of 3D multimodality image integration (3DMMI) to aid presurgical planning is well-established. Multimodality image integration can be technically demanding, and is underutilised in clinical practice. We have developed a single software platform for image integration, 3D visualization and surgical planning. Here, our pipeline is described in step-by-step fashion, starting with image acquisition, proceeding through image co-registration, manual segmentation, brain and vessel extraction, 3D visualization and manual planning of stereoEEG (SEEG) implantations. With dissemination of the software this pipeline can be reproduced in other centres, allowing other groups to benefit from 3DMMI. We also describe the use of an automated, multi-trajectory planner to generate stereoEEG implantation plans. Preliminary studies suggest this is a rapid, safe and efficacious adjunct for planning SEEG implantations. Finally, a simple solution for the export of plans and models to commercial neuronavigation systems for implementation of plans in the operating theater is described. This software is a valuable tool that can support clinical decision making throughout the epilepsy surgery pathway.

  19. Fractographic classification in metallic materials by using 3D processing and computer vision techniques

    Maria Ximena Bastidas-Rodríguez

    2016-09-01

    Full Text Available Failure analysis aims at collecting information about how and why a failure is produced. The first step in this process is a visual inspection on the flaw surface that will reveal the features, marks, and texture, which characterize each type of fracture. This is generally carried out by personnel with no experience that usually lack the knowledge to do it. This paper proposes a classification method for three kinds of fractures in crystalline materials: brittle, fatigue, and ductile. The method uses 3D vision, and it is expected to support failure analysis. The features used in this work were: i Haralick’s features and ii the fractal dimension. These features were applied to 3D images obtained from a confocal laser scanning microscopy Zeiss LSM 700. For the classification, we evaluated two classifiers: Artificial Neural Networks and Support Vector Machine. The performance evaluation was made by extracting four marginal relations from the confusion matrix: accuracy, sensitivity, specificity, and precision, plus three evaluation methods: Receiver Operating Characteristic space, the Individual Classification Success Index, and the Jaccard’s coefficient. Despite the classification percentage obtained by an expert is better than the one obtained with the algorithm, the algorithm achieves a classification percentage near or exceeding the 60 % accuracy for the analyzed failure modes. The results presented here provide a good approach to address future research on texture analysis using 3D data.

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

    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.

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

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

    2009-02-01

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

  2. Aortic dissection or renal infarction: Multislice computed tomographic angiography can tell

    Stojanović Miloš

    2012-01-01

    Full Text Available Introduction. Acute renal infarction as a consequence of renal artery occlusion often goes unrecognized, mostly due to the non-specific clinical features. A quick diagnosis, ideally within three hours of presentation, is a key to renal function recovery. Case Outline. A 62-year-old male patient was admitted with a sudden abdominal pain, right flank pain and nausea. He had a diastolic hypertension at admission and his previous medical history showed atrial fibrillation. Initial clinical diagnosis was aortic dissection. Laboratory findings included elevated lactate dehydrogenase (LDH and serum creatinine levels. There were no signs of aortic dissection or aneurismatic lesions registered during a multislice computed tomographic (MSCT angiography. However, MSCT angiography demonstrated left “upper” renal artery thrombosis and renal infarction - avascular area of the upper two thirds of the left kidney sharply demarcated from the surrounding parenchyma. Both kidneys excreted the contrast. Anticoagulant therapy was initiated, along with antiarrythmic and antihypertensive medications. The follow-up by computed tomography was performed after nine weeks, and it showed a partial revascularization of the previously affected area. Conclusion. Concomitant presence of flank/abdominal pain, an increased risk for thromboembolism and an elevated LDH suggested a possibility of renal infarction. MSCT angiography is a non-invasive and accurate method in the diagnosis of renal artery occlusion and the resulting renal infarction.

  3. Subclinical coronary atherosclerosis identified by coronary computed tomographic angiography in asymptomatic morbidly obese patients

    Peter A. McCullough

    2010-09-01

    Full Text Available Obesity is a common public health problem and obese individuals in particular have a disproportionate incidence of acute coronary events. This study was undertaken to identify coronary artery lesions as well as associated clinical features, risk factors and demographics in patients with a body mass index (BMI >40 kg/m2 without known coronary artery disease (CAD. Morbidly obese subjects were prospectively recruited to undergo coronary computed tomographic angiography (CCTA using a dual-source computed tomography (CT system. CAD was defined as the presence of any atherosclerotic lesion in any one coronary artery segment. The presence, location, and severity of atherosclerosis were related to patient characteristics. Forty-one patients (28 women, mean age, 50.4±10.0 years, mean BMI, 43.8±4.8 kg/m2 served as the study population. Of these, 25 patients (61% had at least one coronary stenosis. All but 2 patients within the CAD cohort had coronary artery calcium (CAC scores >0, and most plaques identified (75.4% were non-calcified. There was a predilection of calcified and non-calcified atherosclerosis involving the left anterior descending (LAD coronary artery compared with other coronary segments. Univariate predictors of CAD included older age, dyslipidemia, and diabetes. In this preliminary study of young morbidly obese patients, CCTA detected a high prevalence of calcified and non-calcified CAD, although the later predominated.

  4. Recent developments in computer-generated holography: toward a practical electroholography system for interactive 3D visualization

    Slinger, Christopher W.; Cameron, Colin D.; Coomber, Stuart D.; Miller, Richard J.; Payne, Doug A.; Smith, Allan P.; Smith, Mark G.; Stanley, Maurice; Watson, Philip J.

    2004-06-01

    This paper will give an overview of some recent developments in electroholography for applications in interactive 3D visualisation. Arguably the ultimate technology for this task, it is the only approach having the potential to deliver full depth cue, 3D images, having resolutions beyond that which can be perceived by the human eye. Despite significant advances by many researchers, the high pixel counts required by the computer generated hologram (CGH) patterns in these systems remain daunting - in practice, systems able to calculate and display reconfigurable CGH having pixel counts of more than one billion may be required for 300 mm width, 3D images. Advances described include novel Fourier mode variants of diffraction specific algorithms and parallel binarisation techniques for design of the CGH patterns; computer architectures for effective implementation of these algorithms for interactive CGH calculation; the latest developments in the Active Tiling spatial light modulator technology and novel replay optics arrangements including folded mirror geometries, viewer tracking alternatives and new horizontal parallax configurations. Throughout, the emphasis is optimisation towards implementation as an interactive electroholography system having practical utility. Some recent results from demonstrations of aspects of the technology will be shown. These include monochrome and colour, static and dynamic, horizontal parallax only (HPO) and full parallax, 3D images, generated from true CGH systems with up to 24 billion pixels.

  5. Role of volume rendered 3-D computed tomography in conservative management of trauma-related thoracic injuries.

    OʼLeary, Donal Peter

    2012-09-01

    Pneumatic nail guns are a tool used commonly in the construction industry and are widely available. Accidental injuries from nail guns are common, and several cases of suicide using a nail gun have been reported. Computed tomographic (CT) imaging, together with echocardiography, has been shown to be the gold standard for investigation of these cases. We present a case of a 55-year-old man who presented to the accident and emergency unit of a community hospital following an accidental pneumatic nail gun injury to his thorax. Volume-rendered CT of the thorax allowed an accurate assessment of the thoracic injuries sustained by this patient. As there was no evidence of any acute life-threatening injury, a sternotomy was avoided and the patient was observed closely until discharge. In conclusion, volume-rendered 3-dimensional CT can greatly help in the decision to avoid an unnecessary sternotomy in patients with a thoracic nail gun injury.

  6. 3D-MAPTOR Code for computation of magnetic fields in tokamaks

    ChÁVez-AlarcÓN, Esteban; Herrera-VelÁZquez, Julio

    2009-11-01

    A 3dimensional code has been developed in order to determine the magnetic field in tokamaks, starting from the assumption that the toroidal and vertical field coils are all circular, as well as the cross section of the plasma current distribution. It was earlier used to study the stochastization of the outer magnetic surfaces [1] and to reconstruct the evolution of the plasma column, using the experimental signals of tokamak discharges. These results were compared with tomographic reconsructions of the ISTTOK tokamak [2]. We present an upgrade of the code, in which rectangular toroidal field coils and D shaped plasma current cross sections can be included. The code is particularly useful to study the effect of the ripple along the toroidal coordinate.[4pt] [1] E. Ch'avez, et al., ``Stochastization of Magnetic Field Surfaces in Tokamaks by an Inner Coil'' in Plasma and Fusion Science, AIP Conference Proceedings Series 875 (2006) pp.347-349.[0pt] [2] B.B. Carvalho, et al., ``Real-time plasma control based on the ISTTOK tomography diagnostic'', Rev. Sci. Instrum. 79 (2008)10F329.

  7. Comparison of two cone beam computed tomographic systems versus panoramic imaging for localization of impacted maxillary canines and detection of root resorption.

    Alqerban, Ali; Jacobs, Reinhilde; Fieuws, Steffen; Willems, Guy

    2011-02-01

    The diagnostic accuracy for the localization of impacted canines and the detection of canine-induced root resorption of maxillary incisors were compared between conventional radiographic procedures using one two-dimensional (2D) panoramic radiograph with that of two three-dimensional (3D) cone beam computed tomography (CBCT) scans. The clinical records of 60 consecutive patients who had impacted or ectopically erupting maxillary canines were identified from those seeking orthodontic treatment. For each case, two sets of radiographic information were obtained. The study sample was divided into two groups: group A (n = 30) included those for whom a dental pantomograph (DPT) and CBCT obtained with a 3D Accuitomo-XYZ Slice View Tomograph were available and group B (n = 30) who had a DPT and CBCT obtained with a Scanora. The DPT and CBCT images were subsequently analysed by 11 examiners. Statistical analysis included an evaluation of the agreement between observers based on the standard error of the measurement, kappa statistics and coefficient of concordance, as well as an assessment of the differences between 2D and 3D imaging employing Wilcoxon signed rank and McNemar tests. There was a highly significant difference between the 2D and 3D images in the width of the canine crown (P resorption of the lateral incisor was also significantly different in both groups (P = 0.0201 and P incisor root resorption was significantly different between the Accuitomo and DPT images (P = 0.045). There was also a significant difference in the severity of lateral incisor root resorption between the DPT and CBCT in both groups (P = 0.02). The results of this study suggest that CBCT is more sensitive than conventional radiography for both canine localization and identification of root resorption of adjacent teeth.

  8. Computation of thermal properties via 3D homogenization of multiphase materials using FFT-based accelerated scheme

    Lemaitre, Sophie; Choi, Daniel; Karamian, Philippe

    2015-01-01

    In this paper we study the thermal effective behaviour for 3D multiphase composite material consisting of three isotropic phases which are the matrix, the inclusions and the coating media. For this purpose we use an accelerated FFT-based scheme initially proposed in Eyre and Milton (1999) to evaluate the thermal conductivity tensor. Matrix and spherical inclusions media are polymers with similar properties whereas the coating medium is metallic hence better conducting. Thus, the contrast between the coating and the others media is very large. For our study, we use RVEs (Representative volume elements) generated by RSA (Random Sequential Adsorption) method developed in our previous works, then, we compute effective thermal properties using an FFT-based homogenization technique validated by comparison with the direct finite elements method. We study the thermal behaviour of the 3D-multiphase composite material and we show what features should be taken into account to make the computational approach efficient.

  9. Implementation of Headtracking and 3D Stereo with Unity and VRPN for Computer Simulations

    Noyes, Matthew A.

    2013-01-01

    This paper explores low-cost hardware and software methods to provide depth cues traditionally absent in monocular displays. The use of a VRPN server in conjunction with a Microsoft Kinect and/or Nintendo Wiimote to provide head tracking information to a Unity application, and NVIDIA 3D Vision for retinal disparity support, is discussed. Methods are suggested to implement this technology with NASA's EDGE simulation graphics package, along with potential caveats. Finally, future applications of this technology to astronaut crew training, particularly when combined with an omnidirectional treadmill for virtual locomotion and NASA's ARGOS system for reduced gravity simulation, are discussed.

  10. 3D game engine design a practical approach to real-time computer graphics

    Eberly, David H

    2006-01-01

    A major revision of the international bestseller on game programming!Graphics hardware has evolved enormously in the last decade. Hardware can now be directly controlled through techniques such as shader programming, which requires an entirely new thought process of a programmer. 3D Game Engine Design, Second Edition shows step-by-step how to make a shader-based graphics engine and how to tame the new technology. Much new material has been added, including more than twice the coverage of the essential techniques of scene graph management, as well as new methods for manag

  11. 3D Quantification of Mandibular Asymmetry through Cone Beam Computed Tomography

    Cevidanes, Lucia H.S.; Alhadidi, Abeer; Paniagua, Beatriz; Styner, Martin; Ludlow, John; Mol, Andre; Turvey, Timothy; Proffit, William R.; Rossouw, Paul Emile

    2011-01-01

    Objective To determine if 3D shape analysis precisely diagnoses right and left differences in asymmetry patients Study Design Cone-beam CT data was acquired pretreatment from 20 patients with mandibular asymmetry. 3D shape analysis was used to localize and quantify the extent of virtually simulated asymmetry. Two approaches were used: (1) mirroring on the midsagittal plane determined from landmarks and (2) mirroring on an arbitrary plane, then registering on the cranial base of the original image. The validation presented in this study used simulated data and has been applied to three clinical cases. Results For mirroring on the midsagittal plane there was a >99% probability that the difference between measured and simulated asymmetry was less than 0.5 mm. For mirroring with cranial base registration, there was a >84% probability of differences less than 0.5 mm. Conclusions Mandibular asymmetry can be precisely quantified with both mirroring methods. Cranial base registration has the potential to be used for patients with trauma situations or when key landmarks are unreliable or absent. PMID:21497527

  12. Utility of Computed Tomographic Enteroclysis/Enterography for the Assessment of Mucosal Healing in Crohn's Disease

    Shinichi Hashimoto

    2013-01-01

    Full Text Available Aim. When determining therapeutic strategy, it is important to diagnose small intestinal lesions in Crohn's disease (CD precisely and to evaluate mucosal healing as well as clinical remission in CD. The purpose of this study was to compare findings from computed tomographic enteroclysis/enterography (CTE with those from the mucosal surface and to determine whether the state of mucosal healing can be determined by CTE. Materials and Methods. Of the patients who underwent CTE for CD, 39 patients were examined whose mucosal findings could be confirmed by colonoscopy, capsule endoscopy, balloon endoscopy, or with the resected surgical specimens. Results. According to the CTE findings, patients were determined to be in the active CD group (n=31 or inactive CD group (n=8. The proportion of previous surgery, clinical remission, stenosis, and CDAI score all showed significant difference between groups. Mucosal findings showed an association with ulcer in 93.6% of active group patients but in only 12.5% of inactive group patients (P<0.0001, whereas mucosal healing was found in 62.5% of inactive group patients but in only 3.2% of active group patients (P<0.0001. Conclusion. CTE appeared to be a useful diagnostic method for assessment of mucosal healing in Crohn's disease.

  13. Thoracic pathologies on scout views and bolus tracking slices for computed tomographic cerebral angiography

    Groth, M.; Fiehler, J.; Buhk, J.H. [University Medical Center Hamburg-Eppendorf (Germany). Dept. of Diagnostic and Interventional Neuroradiology; Henes, F.O. [University Medical Center Hamburg-Eppendorf (Germany). Dept. of Diagnostic and Interventional Radiology

    2015-08-15

    To evaluate the incidence of additional thoracic pathologic findings (TPF) detected on scout views and corresponding bolus tracking slices (SVBT) for computed tomographic cerebral angiography (CTCA) and to test the reliability and accuracy of these findings. The study collective included 505 consecutive patients who underwent multidetector CTCA. Appendant SVBT of all patients were reviewed for any pathologic findings and patient medical reports were analyzed, if any medical treatment was initiated for the detected pathologic findings. In 18 patients thoracic CT scans were performed in the same session. These were additionally reviewed by two blinded observers to test for intra- and interobserver reliability as well as for accuracy of detecting thoracic pathologies on SVBT. TPF were detected in 165 (33 %) SVBT. The five most common pathologic findings were: pleural effusion, 12 %; pneumonia, 8 %; atelectasis/dystelecatsis, 6 %; pericardial effusion, 2 % and elevated diaphragm, 1 %. For 48 % of these findings medical treatment was initiated. SVBT showed a sensitivity of 53 %, a specificity of 99 %, a positive predictive value of 89 %, a negative predictive value of 94 % and accuracy of 94 % for the detection of TPF. The intraobserver reliability was very good and the interobserver reliability showed moderate agreement. SVBT for CTCA should be reviewed with care by radiologists, since additional TPF can affect patient management. Nevertheless, despite a high specificity of SVBT for detecting TPF, an only moderate sensitivity has to be taken into account.

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

    Jodocy, Daniel, E-mail: daniel.jodocy@klinikum-minden.de [Department of Internal Medicine III (Cardiology), Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck (Austria); Abbrederis, Susanne, E-mail: susanne.abbrederis@uki.at [Department of Internal Medicine II (Gastroenterology and Hepatology), Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck (Austria); Graziadei, Ivo W., E-mail: ivo.graziadei@i-med.ac.at [Department of Internal Medicine II (Gastroenterology and Hepatology), Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck (Austria); Vogel, Wolfgang, E-mail: wolfgang.vogel@uki.at [Department of Internal Medicine II (Gastroenterology and Hepatology), Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck (Austria); Pachinger, Otmar, E-mail: otmar.pachinger@uki.at [Department of Internal Medicine III (Cardiology), Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck (Austria); Feuchtner, Gudrun M., E-mail: gudrun.feuchtner@i-med.ac.at [Department of Radiology, Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck (Austria); Jaschke, Werner, E-mail: werner.jaschke@i-med.ac.at [Department of Radiology, Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck (Austria); Friedrich, Guy, E-mail: guy.friedrich@uki.at [Department of Internal Medicine III (Cardiology), Medical University of Innsbruck, Anichstraße 35, A-6020 Innsbruck (Austria)

    2012-09-15

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

  15. Computed tomographic features of 23 sporadic cases with Legionella pneumophila pneumonia

    Yu Hui [Department of Respiratory Diseases, Shanghai Pneumology Hospital, Tongji University, Shanghai (China); Higa, Futoshi; Hibiya, Kenji; Furugen, Makoto [Department of Medicine and Therapeutics, Control and Prevention of Infectious Diseases (First Department of Internal Medicine), Faculty of Medicine, University of the Ryukyus, Okinawa (Japan); Sato, Yoko [Tomishiro Chuo Hospital, Okinawa (Japan); Shinzato, Takashi [Nakagami General Hospital, Okinawa (Japan); Haranaga, Shusaku; Yara, Satomi; Tateyama, Masao [Department of Medicine and Therapeutics, Control and Prevention of Infectious Diseases (First Department of Internal Medicine), Faculty of Medicine, University of the Ryukyus, Okinawa (Japan); Fujita, Jiro, E-mail: fujita@med.u-ryukyu.ac.j [Department of Medicine and Therapeutics, Control and Prevention of Infectious Diseases (First Department of Internal Medicine), Faculty of Medicine, University of the Ryukyus, Okinawa (Japan); Li, Huiping [Department of Respiratory Diseases, Shanghai Pneumology Hospital, Tongji University, Shanghai (China)

    2010-06-15

    Objective: To describe the chest computed tomographic (CT) findings of Legionella pneumophila pneumonia. Methods: CT scans obtained from 23 sporadic cases of L. pneumophila pneumonia were retrospectively reviewed. Chest CT findings were analyzed with regard to the patterns and distributions of pulmonary abnormalities. We also analyzed the histopathology of lungs from guinea pigs with experimentally induced L. pneumophila pneumonia. Results: Consolidation and ground-glass opacity (GGO) were the main findings of CT scans in L. pneumophila pneumonia. The distribution of opacities was categorized as non-segmental (n = 20) and segmental (n = 4). Non-segmental distribution may follow an onset of segmental distribution. Pleural effusion was observed in 14 (58.3%) patients, of which 13 were accompanied with non-segmental distribution. Abscess formation was observed in only one immunocompromised patient. In the animal pneumonia model, the lesions comprised of terminal bronchioles, alveolar spaces, and interstitia. Small bacilli were observed to be contained by many macrophages within the alveoli. Conclusion: Non-segmental distribution was significantly more frequent than segmental distribution in L. pneumophila pneumonia. It is possible that L. pneumophila infection initially results in segmental pneumonia, which progresses to typical non-segmental distribution.

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

    Thamer Alsulaiman

    2016-01-01

    Full Text Available 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.

  17. Computed tomographic findings of skeletal muscles in amyotrophic lateral sclerosis (ALS)

    Takahashi, Ryosuke; Imai, Terukuni; Sadashima, Hiromichi; Matsumoto, Sadayuki; Yamamoto, Toru; Kusaka, Hirobumi; Yamasaki, Masahiro; Maya, Kiyomi; Tanabe, Masaya (Kitano Hospital, Osaka (Japan))

    1989-04-01

    We evaluated the Computed Tomographic (CT) findings of skeletal muscles in 12 cases of amyotrophic lateral sclerosis (ALS), 1 case of spinal progressive muscular atrophy (SPMA), and 1 case of Kugelberg-Welander disease. CT examination was performed in the neck, shoulders, abdomen, pelvis, thighs, and lower legs, 15 muscles were selected for evaluation. The following muscles tended to be affected: m. transversospinalis (12 cases were abnormal), m. deltoideus (10), m. subscapularis (10), m. infraspinatus (10), mm. dorsi (12), hamstring muscles (14), m. tibialis anterior (14), and m. triceps surae (14). On the contrary, the following muscles tended to be preserved: m. sternocleidomastoideus (only 7 cases were abnormal), m. psoas major (7), m. gluteus maximus (7), m. rectus femoris (7), m. sartorius (7) and m. gracilis (6). The distribution of the muscles affected showed neither proximal nor distal dominancy. As the disease advanced, however, all the muscles became affected without any severity. CT findings of skeletal muscles in ALS were characterized by muscle atrophy and fat infiltration, which showed a patchy, linear, or moth-eaten appearance. In mildly affected cases, there was muscle atrophy without internal architectual changes. In moderately affected cases, muscle atrophy advanced and internal architectural changes (patchy, linear, and moth-eaten fat infiltration) became evident. In most advanced cases, every muscle showed a ragged appearance because of severe muscle atrophy and internal architectural changes. These findings were well distinguished from those of SPMA, which resembled the CT pattern of primary muscle diseases. (author).

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

    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.

  19. Computational modeling of optical projection tomographic microscopy using the finite difference time domain method.

    Coe, Ryan L; Seibel, Eric J

    2012-12-01

    We present a method for modeling image formation in optical projection tomographic microscopy (OPTM) using high numerical aperture (NA) condensers and objectives. Similar to techniques used in computed tomography, OPTM produces three-dimensional, reconstructed images of single cells from two-dimensional projections. The model is capable of simulating axial scanning of a microscope objective to produce projections, which are reconstructed using filtered backprojection. Simulation of optical scattering in transmission optical microscopy is designed to analyze all aspects of OPTM image formation, such as degree of specimen staining, refractive-index matching, and objective scanning. In this preliminary work, a set of simulations is performed to examine the effect of changing the condenser NA, objective scan range, and complex refractive index on the final reconstruction of a microshell with an outer radius of 1.5 μm and an inner radius of 0.9 μm. The model lays the groundwork for optimizing OPTM imaging parameters and triaging efforts to further improve the overall system design. As the model is expanded in the future, it will be used to simulate a more realistic cell, which could lead to even greater impact.

  20. Modeling and Analysis of a Lunar Space Reactor with the Computer Code RELAP5-3D/ATHENA

    Carbajo, Juan J [ORNL; Qualls, A L [ORNL

    2008-01-01

    The transient analysis 3-dimensional (3-D) computer code RELAP5-3D/ATHENA has been employed to model and analyze a space reactor of 180 kW(thermal), 40 kW (net, electrical) with eight Stirling engines (SEs). Each SE will generate over 6 kWe; the excess power will be needed for the pumps and other power management devices. The reactor will be cooled by NaK (a eutectic mixture of sodium and potassium which is liquid at ambient temperature). This space reactor is intended to be deployed over the surface of the Moon or Mars. The reactor operating life will be 8 to 10 years. The RELAP5-3D/ATHENA code is being developed and maintained by Idaho National Laboratory. The code can employ a variety of coolants in addition to water, the original coolant employed with early versions of the code. The code can also use 3-D volumes and 3-D junctions, thus allowing for more realistic representation of complex geometries. A combination of 3-D and 1-D volumes is employed in this study. The space reactor model consists of a primary loop and two secondary loops connected by two heat exchangers (HXs). Each secondary loop provides heat to four SEs. The primary loop includes the nuclear reactor with the lower and upper plena, the core with 85 fuel pins, and two vertical heat exchangers (HX). The maximum coolant temperature of the primary loop is 900 K. The secondary loops also employ NaK as a coolant at a maximum temperature of 877 K. The SEs heads are at a temperature of 800 K and the cold sinks are at a temperature of ~400 K. Two radiators will be employed to remove heat from the SEs. The SE HXs surrounding the SE heads are of annular design and have been modeled using 3-D volumes. These 3-D models have been used to improve the HX design by optimizing the flows of coolant and maximizing the heat transferred to the SE heads. The transients analyzed include failure of one or more Stirling engines, trip of the reactor pump, and trips of the secondary loop pumps feeding the HXs of the

  1. Leveraging performance of 3D finite difference schemes in large scientific computing simulations

    De la Cruz, Raúl

    2015-01-01

    Gone are the days when engineers and scientists conducted most of their experiments empirically. During these decades, actual tests were carried out in order to assess the robustness and reliability of forthcoming product designs and prove theoretical models. With the advent of the computational era, scientific computing has definetely become a feasible solution compared with empirical methods, in terms of effort, cost and reliability. Large and massively parallel computational resources have...

  2. Consistency between computed tomographic enterography and enteroscopy in the detection of small intestinal Crohn’s disease

    徐安涛

    2014-01-01

    Objective To evaluate the diagnostic value of computed tomographic enterography(CTE)in the detection of small intestinal Crohn’s disease(CD)with balloon-assisted enterography(BAE)as reference standard.Methods The CTE and BAE data of 81 patients with CD were retrospectively analyzed.The small intestine of CD patients was divided into four segments,such as duode-

  3. Arterial Obstruction on Computed Tomographic or Magnetic Resonance Angiography and Response to Intravenous Thrombolytics in Ischemic Stroke

    Mair, Grant; von Kummer, Rüdiger; Adami, Alessandro; White, Philip M.; Adams, Matthew E.; Yan, Bernard; Demchuk, Andrew M.; Farrall, Andrew J.; Sellar, Robin J.; Sakka, Eleni; Palmer, Jeb; Perry, David; Lindley, Richard I.; Sandercock, Peter A.G.

    2017-01-01

    Background and Purpose— Computed tomographic angiography and magnetic resonance angiography are used increasingly to assess arterial patency in patients with ischemic stroke. We determined which baseline angiography features predict response to intravenous thrombolytics in ischemic stroke using randomized controlled trial data. Methods— We analyzed angiograms from the IST-3 (Third International Stroke Trial), an international, multicenter, prospective, randomized controlled trial of intravenous alteplase. Readers, masked to clinical, treatment, and outcome data, assessed prerandomization computed tomographic angiography and magnetic resonance angiography for presence, extent, location, and completeness of obstruction and collaterals. We compared angiography findings to 6-month functional outcome (Oxford Handicap Scale) and tested for interactions with alteplase, using ordinal regression in adjusted analyses. We also meta-analyzed all available angiography data from other randomized controlled trials of intravenous thrombolytics. Results— In IST-3, 300 patients had prerandomization angiography (computed tomographic angiography=271 and magnetic resonance angiography=29). On multivariable analysis, more extensive angiographic obstruction and poor collaterals independently predicted poor outcome (PHandicap Scale (P≥0.075) in IST-3. In meta-analysis (5 trials of alteplase or desmoteplase, including IST-3, n=591), there was a significantly increased benefit of thrombolytics on outcome (odds ratio>1 indicates benefit) in patients with (odds ratio, 2.07; 95% confidence interval, 1.18–3.64; P=0.011) versus without (odds ratio, 0.88; 95% confidence interval, 0.58–1.35; P=0.566) arterial obstruction (P for interaction 0.017). Conclusions— Intravenous thrombolytics provide benefit to stroke patients with computed tomographic angiography or magnetic resonance angiography evidence of arterial obstruction, but the sample was underpowered to demonstrate significant

  4. Casting directly from a computer model by using advanced simulation software FLOW-3D Cast ®

    M. Sirviö

    2009-01-01

    Full Text Available ConiferRob - A patternless casting technique, originally conceived at VTT Technical Research Centre of Finland and furtherdeveloped at its spin-off company, Simtech Systems, offers up to 40% savings in product development costs, and up to two months shorterdevelopment times compared to conventional techniques. Savings of this order can be very valuable on today's highly competitivemarkets. Casting simulation is commonly used for designing of casting systems. However, most of the software are today old fashioned and predicting just shrinkage porosity. Flow Science, VTT and Simtech have developed new software called FLOW-3D Cast ® , whichcan simulate surface defects, air entrainment, filters, core gas problems and even a cavitation.

  5. Computational Finite Element Software Assisted Development of a 3D Inductively Coupled Power Transfer System

    Pratik Raval

    2014-02-01

    Full Text Available To date inductively coupled power transfer (ICPT systems have already found many practical applications including battery charging pads. In fact, current charging platforms tend to largely support only one- or two-dimensional planar movement in load. This paper proposes a new concept of extending the aspect ratios of the operating power transfer volume of ICPT systems to support arbitrary three dimensional load movements with respect to the primary coils. This is done by use of modern finite element method analysis software to propose the primary and secondary magnetic structures of such an ICPT system. Firstly, two primary magnetic structures are proposed based on contrasting modes of operation and different field directions. This includes a single-phase and multi-phase current model. Next, a secondary magnetic structure is customized to be compatible with both primary structures. The resulting system is shown to produce a 3D power transfer volume for battery cell charging applications.

  6. Incremental prognostic value of coronary computed tomographic angiography over coronary artery calcium score for risk prediction of major adverse cardiac events in asymptomatic diabetic individuals

    J.K. Min (James); T.M. LaBounty (Troy); M. Gomez (Millie); S. Achenbach (Stephan); M. Al-Mallah (Mouaz); M.J. Budoff (Matthew); F. Cademartiri (Filippo); T.Q. Callister (Tracy); H.-J. Chang (Hyuk-Jae); V.Y. Cheng (Victor); K. Chinnaiyan (Kavitha); B.J.W. Chow (Benjamin); R.C. Cury (Ricardo); A. Delago (Augustin); A.M. Dunning (Allison); G.M. Feuchtner (Gudrun); M. Hadamitzky (Martin); J. Hausleiter (Jörg); P.A. Kaufmann (Philipp); Y-J. Kim (Yong-Jin); J. Leipsic (Jonathon); F.Y. Lin (Fay); E. Maffei (Erica); G.L. Raff (Gilbert); L.J. Shaw (Leslee); T.C. Villines (Todd); D.S. Berman (Daniel)

    2014-01-01

    textabstractBackground: Coronary artery disease (CAD) diagnosis by coronary computed tomographic angiography (CCTA) is useful for identification of symptomatic diabetic individuals at heightened risk for death. Whether CCTA-detected CAD enables improved risk assessment of asymptomatic diabetic indiv

  7. A novel structured dictionary for fast processing of 3D medical images, with application to computed tomography restoration and denoising

    Karimi, Davood; Ward, Rabab K.

    2016-03-01

    Sparse representation of signals in learned overcomplete dictionaries has proven to be a powerful tool with applications in denoising, restoration, compression, reconstruction, and more. Recent research has shown that learned overcomplete dictionaries can lead to better results than analytical dictionaries such as wavelets in almost all image processing applications. However, a major disadvantage of these dictionaries is that their learning and usage is very computationally intensive. In particular, finding the sparse representation of a signal in these dictionaries requires solving an optimization problem that leads to very long computational times, especially in 3D image processing. Moreover, the sparse representation found by greedy algorithms is usually sub-optimal. In this paper, we propose a novel two-level dictionary structure that improves the performance and the speed of standard greedy sparse coding methods. The first (i.e., the top) level in our dictionary is a fixed orthonormal basis, whereas the second level includes the atoms that are learned from the training data. We explain how such a dictionary can be learned from the training data and how the sparse representation of a new signal in this dictionary can be computed. As an application, we use the proposed dictionary structure for removing the noise and artifacts in 3D computed tomography (CT) images. Our experiments with real CT images show that the proposed method achieves results that are comparable with standard dictionary-based methods while substantially reducing the computational time.

  8. A cubic interpolation pipeline for fast computation of 3D deformation fields modeled using B-splines

    Castro-Pareja, Carlos R.; Shekhar, Raj

    2006-02-01

    Fast computation of 3D deformation fields is critical to bringing the application of automated elastic image registration algorithms to routine clinical practice. However, it lies beyond the computational power of current microprocessors; therefore requiring implementations using either massively parallel computers or application-specific hardware accelerators. The use of massively parallel computers in a clinical setting is not practical or cost-effective, therefore making the use of hardware accelerators necessary. We present a hardware pipeline that allows accelerating the computation of 3D deformation fields to speeds up to two orders of magnitude faster than software implementations on current workstations and about 64 times faster than other previously reported architectures. The pipeline implements a version of the free-form deformation calculation algorithm, which is optimized to minimize the number of arithmetic operations required to calculate the transformation of a given set of neighboring voxels, thereby achieving an efficient and compact implementation in hardware which allows its use as part of a larger system.

  9. Efficient computation of steady, 3D water-wave patterns, application to hovercraft-type flows

    Lewis, M.R.; Koren, B.

    2002-01-01

    Numerical methods for the computation of stationary free surfaces is the subject of much current research in computational engineering. The present report is directed towards free surfaces in maritime engineering. Of interest here are the long steady waves generated by hovercraft and ships, the grav

  10. 3-D parallel program for numerical calculation of gas dynamics problems with heat conductivity on distributed memory computational systems (CS)

    Sofronov, I.D.; Voronin, B.L.; Butnev, O.I. [VNIIEF (Russian Federation)] [and others

    1997-12-31

    The aim of the work performed is to develop a 3D parallel program for numerical calculation of gas dynamics problem with heat conductivity on distributed memory computational systems (CS), satisfying the condition of numerical result independence from the number of processors involved. Two basically different approaches to the structure of massive parallel computations have been developed. The first approach uses the 3D data matrix decomposition reconstructed at temporal cycle and is a development of parallelization algorithms for multiprocessor CS with shareable memory. The second approach is based on using a 3D data matrix decomposition not reconstructed during a temporal cycle. The program was developed on 8-processor CS MP-3 made in VNIIEF and was adapted to a massive parallel CS Meiko-2 in LLNL by joint efforts of VNIIEF and LLNL staffs. A large number of numerical experiments has been carried out with different number of processors up to 256 and the efficiency of parallelization has been evaluated in dependence on processor number and their parameters.

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

    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 glutamine. GS is the main reason for the uptake of [¹³N]ammonia, and [¹³N]ammonia is a useful tracer for PCa imaging.

  12. 3D hierarchical computational model of wood as a cellular material with fibril reinforced, heterogeneous multiple layers

    Qing, Hai; Mishnaevsky, Leon

    2009-01-01

    A 3D hierarchical computational model of deformation and stiffness of wood, which takes into account the structures of wood at several scale levels (cellularity, multilayered nature of cell walls, composite-like structures of the wall layers) is developed. At the mesoscale, the softwood cell...... is presented as a 3D hexagon-shape-tube with multilayered walls. The layers in the softwood cell are considered as considered as composite reinforced by microfibrils (celluloses). The elastic properties of the layers are determined with Halpin–Tsai equations, and introduced into mesoscale finite element...... cellular model. With the use of the developed hierarchical model, the influence of the microstructure, including microfibril angles (MFAs, which characterizes the orientation of the cellulose fibrils with respect to the cell axis), the thickness of the cell wall, the shape of the cell cross...

  13. Anthropological facial approximation in three dimensions (AFA3D): computer-assisted estimation of the facial morphology using geometric morphometrics.

    Guyomarc'h, Pierre; Dutailly, Bruno; Charton, Jérôme; Santos, Frédéric; Desbarats, Pascal; Coqueugniot, Hélène

    2014-11-01

    This study presents Anthropological Facial Approximation in Three Dimensions (AFA3D), a new computerized method for estimating face shape based on computed tomography (CT) scans of 500 French individuals. Facial soft tissue depths are estimated based on age, sex, corpulence, and craniometrics, and projected using reference planes to obtain the global facial appearance. Position and shape of the eyes, nose, mouth, and ears are inferred from cranial landmarks through geometric morphometrics. The 100 estimated cutaneous landmarks are then used to warp a generic face to the target facial approximation. A validation by re-sampling on a subsample demonstrated an average accuracy of c. 4 mm for the overall face. The resulting approximation is an objective probable facial shape, but is also synthetic (i.e., without texture), and therefore needs to be enhanced artistically prior to its use in forensic cases. AFA3D, integrated in the TIVMI software, is available freely for further testing.

  14. A 3D edge detection technique for surface extraction in computed tomography for dimensional metrology applications

    Yagüe-Fabra, J.A.; Ontiveros, S.; Jiménez, R.

    2013-01-01

    Many factors influence the measurement uncertainty when using computed tomography for dimensional metrology applications. One of the most critical steps is the surface extraction phase. An incorrect determination of the surface may significantly increase the measurement uncertainty. This paper pr...

  15. A Hierarchical Multiscale Particle Computational Method for Simulation of Nanoscale Flows on 3D Unstructured Grids

    2009-08-14

    dimensional Electrostatic Particle-in-Cell Metho - dology on Unstructured Delaunay-Voronoi Grids", Journal of Computational Physics , Vo- lume 228, Issue 10...addresses mathematical and computational issues of par dimensional simulation of flows at the nanoscale. The research addre phenomena in nanoscale flows...sses also the multi-scale physical devices and processes. The DSMC) method are presented, the analysis of statistical es obtained from U3DSMC es

  16. Optimization of computations for adjoint field and Jacobian needed in 3D CSEM inversion

    Dehiya, Rahul; Singh, Arun; Gupta, Pravin K.; Israil, M.

    2017-01-01

    We present the features and results of a newly developed code, based on Gauss-Newton optimization technique, for solving three-dimensional Controlled-Source Electromagnetic inverse problem. In this code a special emphasis has been put on representing the operations by block matrices for conjugate gradient iteration. We show how in the computation of Jacobian, the matrix formed by differentiation of system matrix can be made independent of frequency to optimize the operations at conjugate gradient step. The coarse level parallel computing, using OpenMP framework, is used primarily due to its simplicity in implementation and accessibility of shared memory multi-core computing machine to almost anyone. We demonstrate how the coarseness of modeling grid in comparison to source (comp`utational receivers) spacing can be exploited for efficient computing, without compromising the quality of the inverted model, by reducing the number of adjoint calls. It is also demonstrated that the adjoint field can even be computed on a grid coarser than the modeling grid without affecting the inversion outcome. These observations were reconfirmed using an experiment design where the deviation of source from straight tow line is considered. Finally, a real field data inversion experiment is presented to demonstrate robustness of the code.

  17. Tomographic PIV: principles and practice

    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.

  18. Patient-specific reconstruction utilizing computer assisted 3D modelling for partial bone flap defect in hybrid cranioplasty

    Hueh, Low Peh; Abdullah, Johari Yap; Abdullah, Abdul Manaf; Yahya, Suzana; Idris, Zamzuri; Mohamad, Dasmawati

    2016-12-01

    Autologous cranioplasty using a patient's original bone flap remain the commonest practice nowadays. However, partial bone flap defect is commonly encountered. Replacing the bone flap with pre-moulded synthetic bone flap is costly and not affordable to many patients. Hence most of the small to medium size defect was topped up with alloplastic material on a free hand basis intra-operatively which often resulted in inaccurate implant approximation with unsatisfactory cosmetic result. This study aims to evaluate implant accuracy and cosmetic outcome of cranioplasty candidates who underwent partial bone flap reconstruction utilising computer assisted 3D modelling. 3D images of the skull were obtained from post-craniectomy axial 1-mm spiral computed tomography (CT) scans and a virtual 3D model was generated using the Materialise Mimics software. The Materialise 3-Matic was then utilised to design a patient-specific implant. Prefabrication of the implant was performed by the 3D Objet printer, and a negative gypsum mold was created with the prefabricated cranial implant. Intraoperatively, a hybrid polymethyl methacrylate (PMMA)-autologous cranial implant was produced using the gypsum mold, and fit into the cranial defect. This study is still ongoing at the moment. To date, two men has underwent partial bone flap reconstruction utilising this technique and both revealed satisfactory implant alignment with favourable cosmesis. Mean implant size was 12cm2, and the mean duration of intraoperative reconstruction for the partial bone flap defect was 40 minutes. No significant complication was reported. As a conclusion, this new technique and approach resulted in satisfactory implant alignment and favourable cosmetic outcome. However, more study samples are needed to increase the validity of the study results.

  19. A 3D Computational Study on the Air-Blast Atomization of a Planar Liquid Layer

    Chiodi, Robert; Desjardins, Olivier

    2016-11-01

    The air-blast atomization of a planar liquid layer is a complex fluid phenomenon involving the destabilization of a low speed liquid layer by a high speed gas coflow. While progress has been made in recent years on understanding the instability of the liquid surface, it remains difficult to accurately predict using stability analysis and requires special expertise and equipment to perform thorough experiments. Simulations provide an excellent way to conduct parametric studies to determine the effect of splitter plate geometry and momentum flux ratio on the frequency and wavelengths of instability, however, they are extremely difficult due to the high density ratio and large range of length and time scales present in the flow. Using an accurate conservative level set method in conjunction with a newly reformulated reinitialization equation, we perform 3D simulations of the air-blast atomization of a planar liquid layer and compare them to experiments. We then go on to explore the role momentum flux ratio plays in the longitudinal and transverse wavelengths of instability.

  20. Computed tomography study of VAPEX process in laboratory 3D model

    Wu, G.Q.; Kantzas, A. [Calgary Univ., AB (Canada). Tomographic Imaging and Porous Media Laboratory; Salama, D. [Nexen Inc., Calgary, AB (Canada)

    2008-07-01

    This paper provided details of a 3-D laboratory model of the VAPEX process that used computerized tomography (CT) to examine vapour chamber expansion behaviour in longitudinal and radial directions. The model was comprised of an aluminum cylinder with 2 slotted tubes installed inside to act as injection and production wells. Propane was used as a solvent with heavy oil. The results of experiments conducted with the model showed that the V shape vapour chamber expansion pattern predicted by the 2-D model was a localized phenomenon. The dominant characteristic of the vapour chamber was an overriding of the injected solvent at the top of the model. The overriding was attributed to gravity segregation. The study also showed that longitudinal expansion was more significant than upwards expansion during the early stages of the VAPEX process. Oil production performance was then examined using different solvent injection rates. An analysis of the CT images was conducted to obtain model porosity, density, and oil saturation profiles. The study demonstrated that pressure cycles caused oil to be produced intermittently. Oil swelling by solvent gas dissolution was an important recovery mechanism. It was concluded that solvent soaking can be used to recover additional residual oil during the VAPEX process. 19 refs., 1 tab., 24 figs.

  1. Computer-Assisted 3D Structure Elucidation of Natural Products using Residual Dipolar Couplings.

    Troche-Pesqueira, Eduardo; Anklin, Clemens; Gil, Roberto R; Navarro-Vázquez, Armando

    2017-03-20

    An enhanced computer-assisted procedure for the determination of the relative configuration of natural products, which starts from the molecular formula and uses a combination of conventional 1D and 2D NMR spectra, and residual dipolar couplings (RDCs), is reported. Having already the data acquired (1D/2D NMR and RDCs), the procedure begins with the determination of the molecular constitution using standard computer-assisted structure elucidation (CASE) and is followed by fully automated determination of relative configuration through RDC analysis. In the case of moderately flexible molecules the simplest data-explaining conformational model is selected by the use of the Akaike information criterion.

  2. Linearity of patient positioning detection. A phantom study of skin markers, cone beam computed tomography, and 3D ultrasound

    Ballhausen, Hendrik; Hieber, Sheila; Li, Minglun; Belka, Claus; Reiner, Michael [University Hospital of LMU, Department of Radiation Oncology, Munich (Germany); Parodi, Katia [Ludwig-Maximilian-University, Department of Experimental Physics - Medical Physics, Munich (Germany)

    2015-05-01

    Three-dimensional ultrasound (3D-US) is a modality complementary to kilovoltage cone beam computed tomography (kV-CBCT) and skin markers for patient positioning detection. This study compares the linearity of evaluations based on measurements using a modern 3D-US system (Elekta Clarity {sup registered}; Elekta, Stockholm, Sweden), a kV-CBCT system (Elekta iView {sup registered}), and skin markers. An investigator deliberately displaced a multimodal phantom by up to ± 30 mm along different axes. The following data points were acquired: 27 along the lateral axis, 29 along the longitudinal axis, 27 along the vertical axis, and 27 along the space diagonal. At each of these 110 positions, the displacements according to skin' markers were recorded and scans were performed using both 3D-US and kV-CBCT. Shifts were detected by matching bony anatomy or soft tissue density to a reference planning CT in the case of kV-CBCT and for 3D-US, by matching ultrasound volume data to a reference planning volume. A consensus value was calculated from the average of the four modalities. With respect to this consensus value, the linearity (offset and regression coefficient, i.e., slope), average offset, systematic error, and random error of all four modalities were calculated for each axis. Linearity was similar for all four modalities, with regression coefficients between 0.994 and 1.012, and all offsets below 1 mm. The systematic errors of skin markers and 3D-US were higher than for kV-CBCT, but random errors were similar. In particular, 3D-US demonstrated an average offset of 0.36 mm to the right, 0.08 mm inferiorly, and 0.15 mm anteriorly; the systematic error was 0.36 mm laterally, 0.35 mm longitudinally, and 0.22 mm vertically; the random error was 0.15 mm laterally, 0.30 mm longitudinally, and 0.12 mm vertically. A total of 109 out of 110 (99 %) 3D-US measurements were within 1 mm of the consensus value on either axis. The linearity of 3D-US was no worse than that of skin

  3. Cardiac tissue structure. Electric field interactions in polarizing the heart: 3D computer models and applications

    Entcheva, Emilia

    1998-11-01

    The goal of this research is to investigate the interactions between the cardiac tissue structure and applied electric fields in producing complex polarization patterns. It is hypothesized that the response of the heart in the conditions of strong electric shocks, as those applied in defibrillation, is dominated by mechanisms involving the cardiac muscle structure perceived as a continuum. Analysis is carried out in three-dimensional models of the heart with detailed fiber architecture. Shock-induced transmembrane potentials are calculated using the bidomain model in its finite element implementation. The major new findings of this study can be summarized as follows: (1) The mechanisms of polarization due to cardiac fiber curvature and fiber rotation are elucidated in three-dimensional ellipsoidal hearts of variable geometry; (2) Results are presented showing that the axis of stimulation and the polarization axis on a whole heart level might differ significantly due to geometric and anisotropic factors; (3) Virtual electrode patterns are demonstrated numerically inside the ventricular wall in internal defibrillation conditions. The role of the tissue-bath interface in shaping the shock-induced polarization is revealed; (4) The generation of 3D phase singularity scrolls by shock-induced intramural virtual electrode patterns is proposed as evidence for a possible new mechanism for the failure to defibrillate. The results of this study emphasize the role of unequal anisotropy in the intra- and extracellular domains, as well as the salient fiber architecture characteristics, such as curvature and transmural rotation, in polarizing the myocardium. Experimental support of the above findings was actively sought and found in recent optical mapping studies using voltage-sensitive dyes. If validated in vivo, these findings would significantly enrich the prevailing concepts about the mechanisms of stimulation and defibrillation of the heart.

  4. Speeding-up MADYMO 3D on serial and parallel computers using a portable coding environment

    Tsiandikos, T.; Rooijackers, H.F.L.; Asperen, F.G.J. van; Lupker, H.A.

    1996-01-01

    This paper outlines the strategy and methodology used to create a portable coding environment for the commercial package MADYMO. The objective is to design a global data structure that efficiently utilises the memory and cache of computers, so that one source code can be used for serial, vector and

  5. A computational model for estimating tumor margins in complementary tactile and 3D ultrasound images

    Shamsil, Arefin; Escoto, Abelardo; Naish, Michael D.; Patel, Rajni V.

    2016-03-01

    Conventional surgical methods are effective for treating lung tumors; however, they impose high trauma and pain to patients. Minimally invasive surgery is a safer alternative as smaller incisions are required to reach the lung; however, it is challenging due to inadequate intraoperative tumor localization. To address this issue, a mechatronic palpation device was developed that incorporates tactile and ultrasound sensors capable of acquiring surface and cross-sectional images of palpated tissue. Initial work focused on tactile image segmentation and fusion of position-tracked tactile images, resulting in a reconstruction of the palpated surface to compute the spatial locations of underlying tumors. This paper presents a computational model capable of analyzing orthogonally-paired tactile and ultrasound images to compute the surface circumference and depth margins of a tumor. The framework also integrates an error compensation technique and an algebraic model to align all of the image pairs and to estimate the tumor depths within the tracked thickness of a palpated tissue. For validation, an ex vivo experimental study was conducted involving the complete palpation of 11 porcine liver tissues injected with iodine-agar tumors of varying sizes and shapes. The resulting tactile and ultrasound images were then processed using the proposed model to compute the tumor margins and compare them to fluoroscopy based physical measurements. The results show a good negative correlation (r = -0.783, p = 0.004) between the tumor surface margins and a good positive correlation (r = 0.743, p = 0.009) between the tumor depth margins.

  6. 3-D Computer Animation vs. Live-Action Video: Differences in Viewers' Response to Instructional Vignettes

    Smith, Dennie; McLaughlin, Tim; Brown, Irving

    2012-01-01

    This study explored computer animation vignettes as a replacement for live-action video scenarios of classroom behavior situations previously used as an instructional resource in teacher education courses in classroom management strategies. The focus of the research was to determine if the embedded behavioral information perceived in a live-action…

  7. Computation of 3D steady Navier-Stokes flow with free-surface gravity waves

    Lewis, M.R.; Koren, B.; Raven, H.C.

    2003-01-01

    In this paper an iterative method for the computation of stationary gravity-wave solutions is investigated, using a novel formulation of the free-surface (FS) boundary-value problem. This method requires the solution of a sequence of stationary Reynolds-Averaged Navier-Stokes subproblems employing t

  8. Computation of 3D Steady Navier-Stokes Flow with Free-Surface Gravity Waves

    Lewis, M.R.; Koren, B.; Raven, H.C.

    2003-01-01

    In this paper an iterative method for the computation of stationary gravity-wave solutions is investigated, using a novel formulation of the free-surface (FS) boundary-value problem. This method requires the solution of a sequence of stationary Reynolds-Averaged Navier-Stokes subproblems employing t

  9. Assessing and improving seismic tomography models using 3-D numerical wave simulations. Geologica Ultraiectina (308)

    Bozdag, H.E.

    2009-01-01

    We have reached a stage in seismic tomography where further refinements with classical techniques become very difficult. Advances in numerical methods and computational facilities are providing new opportunities in seismic tomography to enhance the resolution of tomographic mantle images. 3-D numeri

  10. Computational 3D structures of drug-targeting proteins in the 2009-H1N1 influenza A virus

    Du, Qi-Shi; Wang, Shu-Qing; Huang, Ri-Bo; Chou, Kuo-Chen

    2010-01-01

    The neuraminidase (NA) and M2 proton channel of influenza virus are the drug-targeting proteins, based on which several drugs were developed. However these once powerful drugs encountered drug-resistant problem to the H5N1 and H1N1 flu. To address this problem, the computational 3D structures of NA and M2 proteins of 2009-H1N1 influenza virus were built using the molecular modeling technique and computational chemistry method. Based on the models the structure features of NA and M2 proteins were analyzed, the docking structures of drug-protein complexes were computed, and the residue mutations were annotated. The results may help to solve the drug-resistant problem and stimulate designing more effective drugs against 2009-H1N1 influenza pandemic.

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

    Zhang, Xin; Xiong, Shijiang; Ma, Yue; Han, Ting; Chen, Xinyu; Wan, Fang; Lu, Yating; Yan, Songhe; Wang, Yan

    2015-01-01

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

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

    Xin Zhang

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

  13. Computed tomographic-guided iodine-125 interstitial implants for malignant thoracic tumors

    Huang, Qiming [The Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou 350005 (China); The Department of Radiology, Second Affiliated Hospital of Fujian Medical University, 34 Zhongshan Bei Road, Quanzhou 362000 (China); Chen, Jin; Chen, Qunlin [The Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou 350005 (China); Lai, Qingquan; Cai, Siqing [The Department of Radiology, Second Affiliated Hospital of Fujian Medical University, 34 Zhongshan Bei Road, Quanzhou 362000 (China); Luo, Kaidong [The Department of Radiology, Longyan Hosptial of Traditional Chinese Medical, 59 Longteng Middle Road, Longyan 364000 (China); Lin, Zhengyu, E-mail: linsinlan@yahoo.com.cn [The Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou 350005 (China)

    2013-11-01

    Purpose: To evaluate the feasibility and efficacy of percutaneous interstitial brachytherapy using iodine-125 ({sup 125}I) radioactive seeds under computed tomographic (CT) guidance for malignant thoracic tumors. Materials and methods: Forty-one patients (34 males, 7 females; 18–90 years; mean, 63.7 years) with 77 lesions (3 in the mediastinum, 7 in the chest wall, 67 in the lung) underwent percutaneous interstitial implantation of {sup 125}I radioactive seeds under CT guidance. A treatment planning system (TPS) was employed to calculate the number and distribution of seeds preoperatively. An 18-G needle was inserted into the lesions under CT guidance and send the seeds according to TPS. Two patients with mediastinal lesions undergoing seed implantation received an artificial pneumothorax. One patient with lung carcinoma adjacent to the anterior mediastinum underwent seed implantation through the sternum. Follow-up CT was done every 2 months postoperatively. Results: The procedure was successful in all patients. No major procedure-associated death occurred. The mean duration of follow-up was 19.4 ± 1.3 months (3–49 months). A complete response (CR) was seen in 49 lesions (63.6%), partial response (PR) in 9 lesions (11.7%), stable disease (SD) in 12 lesions (12.8%), and progressive disease (PD) in 7 lesions (7.4%). The overall response rate (CR + PR) was 75.3%; the local control rate (CR + PR + SD) was 90.9%. The 1-, 2- and 3-year progression-free rates for local tumors were 91%, 88% and 88%, respectively. The 1-, 2- and 3-year survival rates were 87%, 74% and 68%, respectively. Conclusion: Implantation of CT-guided {sup 125}I seeds is feasible and effective for patients with malignant thoracic tumors.

  14. Radiation dose to patients and image quality evaluation from coronary 256-slice computed tomographic angiography

    Chen, Liang-Kuang [Department of Radiology, Shin Kong Wu Ho-Su Memorial Hospital, Taiwan (China); College of Medicine, Fu Jen Catholic University, Taiwan (China); Department of Radiological Technology, Yuan Pei University, Taiwan (China); Wu, Tung-Hsin [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, 155 Li-Nong St., Section 2, Taipei 112, Taiwan (China); Yang, Ching-Ching [Department of Radiological Technology, Tzu Chi College of Technology, Hualien, Taiwan (China); Tsai, Chia-Jung [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, 155 Li-Nong St., Section 2, Taipei 112, Taiwan (China); Lee, Jason J.S., E-mail: jslee@ym.edu.t [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, 155 Li-Nong St., Section 2, Taipei 112, Taiwan (China)

    2010-07-21

    The aim of this study is to assess radiation dose and the corresponding image quality from suggested CT protocols which depends on different mean heart rate and high heart rate variability by using 256-slice CT. Fifty consecutive patients referred for a cardiac CT examination were included in this study. All coronary computed tomographic angiography (CCTA) examinations were performed on a 256-slice CT scanner with one of five different protocols: retrospective ECG-gating (RGH) with full dose exposure in all R-R intervals (protocol A), RGH of 30-80% pulsing window with tube current modulation (B), RGH of 78{+-}5% pulsing window with tube current modulation (C), prospective ECG-triggering (PGT) of 78% R-R interval with 5% padding window (D) and PGT of 78% R-R interval without padding window (E). Radiation dose parameters and image quality scoring were determined and compared. In this study, no significant differences were found in comparison on image quality of the five different protocols. Protocol A obtained the highest radiation dose comparing with those of protocols B, C, D and E by a factor of 1.6, 2.4, 2.5 and 4.3, respectively (p<0.001), which were ranged between 2.7 and 11.8 mSv. The PGT could significantly reduce radiation dose delivered to patients, as compared to the RGH. However, the use of PGT has limitations and is only good in assessing cases with lower mean heart rate and stable heart rate variability. With higher mean heart rate and high heart rate variability circumstances, the RGH within 30-80% of R-R interval pulsing window is suggested as a feasible technique for assessing diagnostic performance.

  15. High-resolution computed tomographic findings of Aspergillus infection in lung transplant patients

    Gazzoni, Fernando Ferreira, E-mail: gazzoni4@gmail.com [Hospital de Clínicas de Porto Alegre, Av. Cristovão Colombo 4105, ap.603-C, Post Code: 90560-005, Porto Alegre, RS (Brazil); Hochhegger, Bruno, E-mail: brunohochhegger@gmail.com [Santa Casa de Porto Alegre, Rua 24 de outubro 925/903, Post Code: 90510-002, Porto Alegre, RS (Brazil); Severo, Luiz Carlos, E-mail: severo@santacasa.tche.br [Federal University of Rio Grande do Sul, Rua Ramiro Barcelos, 2400, 2° andar, Post Code: 90035-003, Porto Alegre, RS (Brazil); Marchiori, Edson, E-mail: edmarchiori@gmail.com [Federal University of Rio de Janeiro, Radiology Department, Av. Pedro Calmon, n° 550 – Cidade Universitária, Post Code: 21941-901, Rio de Janeiro, RJ (Brazil); Pasqualotto, Alessandro, E-mail: acpasqualotto@hotmail.com [Santa Casa de Porto Alegre, Rua 24 de outubro 925/903, Post Code: 90510-002, Porto Alegre, RS (Brazil); Sartori, Ana Paula Garcia, E-mail: ana_sartori@hotmail.com [Santa Casa de Porto Alegre, Rua 24 de outubro 925/903, Post Code: 90510-002, Porto Alegre, RS (Brazil); Schio, Sadi, E-mail: smschio@hotmail.com [Santa Casa de Porto Alegre, Rua 24 de outubro 925/903, Post Code: 90510-002, Porto Alegre, RS (Brazil); Camargo, José, E-mail: jjcamargo@terra.com.br [Santa Casa de Porto Alegre, Rua 24 de outubro 925/903, Post Code: 90510-002, Porto Alegre, RS (Brazil)

    2014-01-15

    Objective: The aim of this study was to assess high-resolution computed tomographic (HRCT) findings at presentation in lung transplant patients diagnosed with pulmonary Aspergillus infection. Materials and methods: We retrospectively reviewed HRCT findings from 23 patients diagnosed with pulmonary aspergillosis. Imaging studies were performed 2–5 days after the onset of symptoms. The patient sample comprised 12 men and 11 women aged 22–59 years (mean age, 43.6 years). All patients had dyspnea, tachypnea, and cough. Diagnoses were established with Platelia Aspergillus enzyme immunoassays for galactomannan antigen detection in bronchoalveolar lavage and recovery of symptoms, and HRCT findings after voriconazole treatment. The HRCT scans were reviewed independently by two observers who reached a consensus decision. Results: The main HRCT pattern, found in 65% (n = 15) of patients, was centrilobular tree-in-bud nodules associated with bronchial thickening. This pattern was described in association with areas of consolidation and ground-glass opacities in 13% (n = 3) of patients. Consolidation and ground-glass opacities were the main pattern in 22% (n = 5) of patients. The pattern of large nodules with and without the halo sign was observed in 13% (n = 3) of patients, and were associated with consolidation and ground-glass opacities in one case. Conclusion: The predominant HRCT findings in lung transplant patients with pulmonary aspergillosis were bilateral bronchial wall thickening and centrilobular opacities with the tree-in-bud pattern. Ground-glass opacities and/or bilateral areas of consolidation were also common findings. Pulmonary nodules with the halo sign were found in only 13% of patients.

  16. Role of computed tomographic colonoscopy of postoperative surveillance in patient with gastric cancer

    Dae Won Jun; Dong Hoo Lee; Oh Young Lee; Hyun Chul Lim; Sung Joon Kwon; Hang Lak Lee; Byung Chul Yoon; Ho Soon Choi; Joon Soo Hahm; Min Ho Lee

    2007-01-01

    AIM: To examine the diagnostic yield of colorectal neoplasia at computed tomographic colonoscopy (CTC) as well as the feasibility of contrast enhanced CTC in patients with gastric cancer.METHODS: To examine the incidence of colon polyp we selected postoperative 188 gastric cancer patients, which we refer to as the 'colon polyp survey group'. To examine the feasibility of CTC for early detection of colon cancer or advanced colon adenoma, we selected 47 gastric cancer patients (M:F 29:18, mean age 53.8 years), which we call the 'CT colonoscopy group'. All the 47 patients underwent successive CTC and colonoscopy on the same day.RESULTS: Totally 109 colon polyps were observed from 59 out of 188 gastric cancer patients, the incidence rate of colon polyps in gastric cancer patients being 31.4%. The sensitivity of CTC in detecting individuals with at least 1 lesion of any size was 57.1%, the specificity was 72.7%, the positive predictive value was 47.1%, and the negative predictive value was 71.9%. When the cutoff size was decreased to 6 mm, the sensitivity and specificity were 80.0% and 92.9%, respectively, with positive and negative predictive values of 57.1% and 97.5%, respectively. Only one patient was classified as false negative by virtual colonoscopy.CONCLUSION: The diagnostic yield of colorectal polyp was 31.4% in patients with gastric cancer, and contrast enhanced CTC is an acceptable tool for the detection of synchronous colorectal advanced adenoma and postoperative surveillance of gastric cancer patients.

  17. Fibromuscular dysplasia in living renal donors: Still a challenge to computed tomographic angiography

    Blondin, D., E-mail: blondin@med.uni-duesseldorf.d [Institute of Radiology, University Hospital Duesseldorf, Moorenstr. 5, D-40225 Duesseldorf (Germany); Lanzman, R.; Schellhammer, F. [Institute of Radiology, University Hospital Duesseldorf, Moorenstr. 5, D-40225 Duesseldorf (Germany); Oels, M. [Department of Nephrology (Germany); Grotemeyer, D. [Department of Vascular Surgery and Renal Transplantation (Germany); Baldus, S.E. [Institute of Pathology (Germany); Rump, L.C. [Department of Nephrology (Germany); Sandmann, W. [Department of Vascular Surgery and Renal Transplantation (Germany); Voiculescu, A. [Department of Nephrology (Germany)

    2010-07-15

    Background: Computed tomographic angiography has become the standard evaluating method of potential living renal donors in most centers. Although incidence of fibromuscular dysplasia is low (3.5-6%), this pathology may be relevant for success of renal transplantation. The incidence of FMD in our population of LRD and reliability of CTA for detecting vascular pathology were the aims of this study. Materials and methods: 101 living renal donors, examined between 7/2004 and 9/2008 by CTA, were included in a retrospective evaluation. The examinations were carried out using a 64 Multi-detector CT (Siemens Medical Solutions, Erlangen). The presence or absence of the characteristic signs of fibromuscular dysplasia, as 'string-of-beads' appearance, focal stenosis or aneurysms, were assessed and graded from mild (=1) to severe (=3). Furthermore, vascular anatomy and arterial stenosis were investigated in this study. Retrospective analysis of CTA and ultrasound were compared with operative and histological reports. Results: Four cases of fibromuscular dysplasia (incidence 3.9%) in 101 renal donors were diagnosed by transplanting surgeons and histopathology, respectively. Three cases could be detected by CTA. In one donor even retrospective analysis of CTA was negative. Ten accessory arteries, 14 venous anomalies and 12 renal arteries stenosis due to atherosclerosis were diagnosed by CTA and could be confirmed by the operative report. Conclusion: CTA is sufficient for detection of hemodynamic relevant stenosis and vascular anatomy. Only one patient with a mild form of FMD was under estimated. Therefore, if the CTA shows slightest irregularities which are not typical for atherosclerotic lesions, further diagnostic work up by DSA might still be necessary.

  18. 3D artificial bones for bone repair prepared by computed tomography-guided fused deposition modeling for bone repair.

    Xu, Ning; Ye, Xiaojian; Wei, Daixu; Zhong, Jian; Chen, Yuyun; Xu, Guohua; He, Dannong

    2014-09-10

    The medical community has expressed significant interest in the development of new types of artificial bones that mimic natural bones. In this study, computed tomography (CT)-guided fused deposition modeling (FDM) was employed to fabricate polycaprolactone (PCL)/hydroxyapatite (HA) and PCL 3D artificial bones to mimic natural goat femurs. The in vitro mechanical properties, in vitro cell biocompatibility, and in vivo performance of the artificial bones in a long load-bearing goat femur bone segmental defect model were studied. All of the results indicate that CT-guided FDM is a simple, convenient, relatively low-cost method that is suitable for fabricating natural bonelike artificial bones. Moreover, PCL/HA 3D artificial bones prepared by CT-guided FDM have more close mechanics to natural bone, good in vitro cell biocompatibility, biodegradation ability, and appropriate in vivo new bone formation ability. Therefore, PCL/HA 3D artificial bones could be potentially be of use in the treatment of patients with clinical bone defects.

  19. Sentinel Lymph Node Detection by 3D Freehand Single-Photon Emission Computed Tomography in Early Stage Breast Cancer

    Salih Sinan Gültekin

    2016-06-01

    Full Text Available We herein present our first experience obtained by 3D freehand single-photon emission computed tomography (SPECT (F-SPECT guidance for sentinel lymph node detection (SLND in two patients with early stage breast cancer. F-SPECT guidance was carried out using one-day protocol in one case and by the two-day protocol in the other one. SLND was performed successfully in both patients. Histopathologic evaluation showed that the excised nodes were tumor negative. Thus, patients underwent breast-conserving surgery alone.

  20. High-Performance Computation of Distributed-Memory Parallel 3D Voronoi and Delaunay Tessellation

    Peterka, Tom; Morozov, Dmitriy; Phillips, Carolyn

    2014-11-14

    Computing a Voronoi or Delaunay tessellation from a set of points is a core part of the analysis of many simulated and measured datasets: N-body simulations, molecular dynamics codes, and LIDAR point clouds are just a few examples. Such computational geometry methods are common in data analysis and visualization; but as the scale of simulations and observations surpasses billions of particles, the existing serial and shared-memory algorithms no longer suffice. A distributed-memory scalable parallel algorithm is the only feasible approach. The primary contribution of this paper is a new parallel Delaunay and Voronoi tessellation algorithm that automatically determines which neighbor points need to be exchanged among the subdomains of a spatial decomposition. Other contributions include periodic and wall boundary conditions, comparison of our method using two popular serial libraries, and application to numerous science datasets.

  1. Accurate computation of Galerkin double surface integrals in the 3-D boundary element method

    Adelman, Ross; Duraiswami, Ramani

    2015-01-01

    Many boundary element integral equation kernels are based on the Green's functions of the Laplace and Helmholtz equations in three dimensions. These include, for example, the Laplace, Helmholtz, elasticity, Stokes, and Maxwell's equations. Integral equation formulations lead to more compact, but dense linear systems. These dense systems are often solved iteratively via Krylov subspace methods, which may be accelerated via the fast multipole method. There are advantages to Galerkin formulations for such integral equations, as they treat problems associated with kernel singularity, and lead to symmetric and better conditioned matrices. However, the Galerkin method requires each entry in the system matrix to be created via the computation of a double surface integral over one or more pairs of triangles. There are a number of semi-analytical methods to treat these integrals, which all have some issues, and are discussed in this paper. We present novel methods to compute all the integrals that arise in Galerkin fo...

  2. How computer science can help in understanding the 3D genome architecture.

    Shavit, Yoli; Merelli, Ivan; Milanesi, Luciano; Lio', Pietro

    2016-09-01

    Chromosome conformation capture techniques are producing a huge amount of data about the architecture of our genome. These data can provide us with a better understanding of the events that induce critical regulations of the cellular function from small changes in the three-dimensional genome architecture. Generating a unified view of spatial, temporal, genetic and epigenetic properties poses various challenges of data analysis, visualization, integration and mining, as well as of high performance computing and big data management. Here, we describe the critical issues of this new branch of bioinformatics, oriented at the comprehension of the three-dimensional genome architecture, which we call 'Nucleome Bioinformatics', looking beyond the currently available tools and methods, and highlight yet unaddressed challenges and the potential approaches that could be applied for tackling them. Our review provides a map for researchers interested in using computer science for studying 'Nucleome Bioinformatics', to achieve a better understanding of the biological processes that occur inside the nucleus.

  3. Computer-aided determination of occlusal contact points for dental 3-D CAD.

    Maruyama, Tomoaki; Nakamura, Yasuo; Hayashi, Toyohiko; Kato, Kazumasa

    2006-05-01

    Present dental CAD systems enable us to design functional occlusal tooth surfaces which harmonize with the patient's stomatognathic function. In order to avoid occlusal interferences during tooth excursions, currently available systems usually use the patient's functional occlusal impressions for the design of occlusal contact points. Previous interfere-free design, however, has been done on a trial-and-error basis by using visual inspection. To improve this time-consuming procedure, this paper proposes a computer-aided system for assisting in the determination of the occlusal contact points by visualizing the appropriate regions of the opposing surface. The system can designate such regions from data of the opposing occlusal surfaces and their relative movements can be simulated by using a virtual articulator. Experiments for designing the crown of a lower first molar demonstrated that all contact points selected within the designated regions completely satisfied the required contact or separation during tooth excursions, confirming the effectiveness of our computer-aided procedure.

  4. EVALUATION OF THE LIVER METASTASIS BY 3D-COMPUTED TOMOGRAPHY

    Iuliana Eva; R.C. Tiutiuca

    2005-01-01

    Abdominal spiral computed tomography is the method of choice for the diagnosis of hepatic metastasis, evaluating lesions even under 10 mm. Treatment depends of the hepatic and extrahepatic spread of disease. Therapeutical options include surgical ablation (resection, enucleation, crioablation, radiofrequency, liver transplant) or non-surgical (embolization or chemoembolization, therapeutic aproach through the hepatic artery). Precise diagnostic and evaluation of the extension of the disease...

  5. 3-D finite element computation and dynamic modal analysis on ultrasonic vibration systems

    倪金刚; 张学仁; 聂景旭(Department of Jet Propulsion 405; Beijing University of Aeronautics and Astronautics; Beijing 100083; China)

    1996-01-01

    Stress and modal analyses are performed on an ultrasonic vibration system by means of a 3-dimensional finite element computation and dynamic modal analysis code "Algor" The system consists of an edge-cracked specimen linked elastically with one or two amplifying horns which come into resonant longitudinal vibration at 20kHz.Operating principle of the ultrasonic fatigue machines and experimental procedures for ultrasonic fatigue crack growth studies are briefly presented.

  6. Personalized mitral valve closure computation and uncertainty analysis from 3D echocardiography.

    Grbic, Sasa; Easley, Thomas F; Mansi, Tommaso; Bloodworth, Charles H; Pierce, Eric L; Voigt, Ingmar; Neumann, Dominik; Krebs, Julian; Yuh, David D; Jensen, Morten O; Comaniciu, Dorin; Yoganathan, Ajit P

    2017-01-01

    Intervention planning is essential for successful Mitral Valve (MV) repair procedures. Finite-element models (FEM) of the MV could be used to achieve this goal, but the translation to the clinical domain is challenging. Many input parameters for the FEM models, such as tissue properties, are not known. In addition, only simplified MV geometry models can be extracted from non-invasive modalities such as echocardiography imaging, lacking major anatomical details such as the complex chordae topology. A traditional approach for FEM computation is to use a simplified model (also known as parachute model) of the chordae topology, which connects the papillary muscle tips to the free-edges and select basal points. Building on the existing parachute model a new and comprehensive MV model was developed that utilizes a novel chordae representation capable of approximating regional connectivity. In addition, a fully automated personalization approach was developed for the chordae rest length, removing the need for tedious manual parameter selection. Based on the MV model extracted during mid-diastole (open MV) the MV geometric configuration at peak systole (closed MV) was computed according to the FEM model. In this work the focus was placed on validating MV closure computation. The method is evaluated on ten in vitro ovine cases, where in addition to echocardiography imaging, high-resolution μCT imaging is available for accurate validation.

  7. Usefulness of 3D-CT angiography using multislice CT for diagnosing cardiovascular anomalies in infants

    Kani, Hiroyuki; Matsuki, Mitsuru; Masuda, Kiyohiro; Narabayashi, Isamu; Katayama, Hiroshi; Mori, Yasuhiko; Tamai, Hiroshi [Osaka Medical Coll., Takatsuki (Japan)

    2003-05-01

    We compared three-dimensional computed tomographic angiography using multislice CT (3D-CTA) with echocardiography and angiography in terms of usefulness in the diagnosis of 13 infants with cardiovascular anomalies. 3D-CTA clearly depicted stenoses of the pulmonary artery and vein, and coarctation of the aorta in some cases, which could not be revealed by echocardiography and angiography. Moreover, it provided objectively more information on vascular morphologic characteristics and 3D anatomic relations than echocardiography and angiography. 3D-CTA is a noninvasive and convenient diagnostic technique for cardiovascular anomalies in infants. (author)

  8. ALGEBRAIC TURBULENCE MODEL WITH MEMORY FOR COMPUTATION OF 3-D TURBULENT BOUNDARY LAYERS WITH VALIDATION

    2000-01-01

    Additional equations were found based on experiments for an algebraic turbulence model to improve the prediction of the behavior of three dimensional turbulent boundary layers by taking account of the effects of pressure gradient and the historical variation of eddy viscosity, so the model is with memory. Numerical calculation by solving boundary layer equations was carried out for the five pressure driven three dimensional turbulent boundary layers developed on flat plates, swept-wing, and prolate spheroid in symmetrical plane. Comparing the computational results with the experimental data, it is obvious that the prediction will be more accurate if the proposed closure equations are used, especially for the turbulent shear stresses.

  9. The Computational Complexity of Portal and Other 3D Video Games

    Erik D. Demaine; Lockhart, Joshua; Lynch, Jayson

    2016-01-01

    We classify the computational complexity of the popular video games Portal and Portal 2. We isolate individual mechanics of the game and prove NP-hardness, PSPACE-completeness, or (pseudo)polynomiality depending on the specific game mechanics allowed. One of our proofs generalizes to prove NP-hardness of many other video games such as Half-Life 2, Halo, Doom, Elder Scrolls, Fallout, Grand Theft Auto, Left 4 Dead, Mass Effect, Deus Ex, Metal Gear Solid, and Resident Evil. These results build o...

  10. Computer simulation of 2-D and 3-D ion beam extraction and acceleration

    Ido, Shunji; Nakajima, Yuji [Saitama Univ., Urawa (Japan). Faculty of Engineering

    1997-03-01

    The two-dimensional code and the three-dimensional code have been developed to study the physical features of the ion beams in the extraction and acceleration stages. By using the two-dimensional code, the design of first electrode(plasma grid) is examined in regard to the beam divergence. In the computational studies by using the three-dimensional code, the axis-off model of ion beam is investigated. It is found that the deflection angle of ion beam is proportional to the gap displacement of the electrodes. (author)

  11. Computational studies of hard-body and 3-D effects in plume flows

    Venkatapathy, Ethiraj; Feiereisen, William J.; Obayashi, Shigeru

    1989-01-01

    Axisymmetric and three-dimensional, multi-nozzle plume flows around generic rocket geometries are investigated with a three-dimensional Navier-Stokes solver to study the interactive effects between hard body and the plume. Time-asymptotic, laminar, ideal-gas solutions obtained with a two-factor, flux-split scheme and a diagonal, upwind scheme are presented. Computed solutions to three-dimensional, multi-nozzle problems and single-nozzle, axisymmetric problems demonstrate flow field features including three-dimensionality and hard-body effects. Geometry and three-dimensional effects are shown to be significant in multi-nozzle flows.

  12. Simplified 3D model of a PWR reactor vessel using fluid dynamics code ANSYS CFX computational; Modelo simplificado 3D de la vasija de un reactor PWR mediante el codigo de dinamica de fluidos computacional ANSYS CFX

    Martinez, M.; Miro, R.; Barrachina, T.; Verdu, G.

    2011-07-01

    This paper presents the results from the calculation of the steady state simulation with model of CFD (computational fluid dynamic) operating under conditions of operation at full power (Hot Full Power). Development and the CFD model results show the usefulness of these codes for calculating 3D of the variable thermohydraulics of these reactors.

  13. Comparison of predicting drag methods using computational fluid dynamics in 2d/3d viscous flow

    ZHU; ZiQiang; WANG; XiaoLu; LIU; Jie; LIU; Zhou

    2007-01-01

    As a result of the necessity of aircraft engineering design and the progress of computational fluid dynamics (CFD), techniques of accurately predicting aerodynamic drag are being increasingly explored. According to the momentum balance, the drag can be represented by an integral over a cross-flow plane (called wake integration method) at an arbitrary distance behind the configuration. A formulation to reduce the size of the wake cross plane region required for calculating the drag is developed by using cutoff parameters of vorticity and entropy. This increases the calculation accuracy and decreases the computation time required. Numerical experiments are made to obtain the threshold values of these cutoff parameters. The wake integration method is applied to predict drags of some examples including airfoil, a variety of wings and wing-body combination. Numerical results are compared with those of traditional surface integration method, showing that the predicting drag values with the wake integration method are closer to the experimental data. The results also show that drag prediction within engineering accuracy is possible by using CFD and the numerical drag optimization of complex aircraft configurations is possible, too.

  14. On a 3-D singularity element for computation of combined mode stress intensities

    Atluri, S. N.; Kathiresan, K.

    1976-01-01

    A special three-dimensional singularity element is developed for the computation of combined modes 1, 2, and 3 stress intensity factors, which vary along an arbitrarily curved crack front in three dimensional linear elastic fracture problems. The finite element method is based on a displacement-hybrid finite element model, based on a modified variational principle of potential energy, with arbitrary element interior displacements, interelement boundary displacements, and element boundary tractions as variables. The special crack-front element used in this analysis contains the square root singularity in strains and stresses, where the stress-intensity factors K(1), K(2), and K(3) are quadratically variable along the crack front and are solved directly along with the unknown nodal displacements.

  15. Users manual for CAFE-3D : a computational fluid dynamics fire code.

    Khalil, Imane; Lopez, Carlos; Suo-Anttila, Ahti Jorma (Alion Science and Technology, Albuquerque, NM)

    2005-03-01

    The Container Analysis Fire Environment (CAFE) computer code has been developed to model all relevant fire physics for predicting the thermal response of massive objects engulfed in large fires. It provides realistic fire thermal boundary conditions for use in design of radioactive material packages and in risk-based transportation studies. The CAFE code can be coupled to commercial finite-element codes such as MSC PATRAN/THERMAL and ANSYS. This coupled system of codes can be used to determine the internal thermal response of finite element models of packages to a range of fire environments. This document is a user manual describing how to use the three-dimensional version of CAFE, as well as a description of CAFE input and output parameters. Since this is a user manual, only a brief theoretical description of the equations and physical models is included.

  16. Fast and Precise 3D Computation of Capacitance of Parallel Narrow Beam MEMS Structures

    Majumdar, N

    2007-01-01

    Efficient design and performance of electrically actuated MEMS devices necessitate accurate estimation of electrostatic forces on the MEMS structures. This in turn requires thorough study of the capacitance of the structures and finally the charge density distribution on the various surfaces of a device. In this work, nearly exact BEM solutions have been provided in order to estimate these properties of a parallel narrow beam structure found in MEMS devices. The effect of three-dimensionality, which is an important aspect for these structures, and associated fringe fields have been studied in detail. A reasonably large parameter space has been covered in order to follow the variation of capacitance with various geometric factors. The present results have been compared with those obtained using empirical parametrized expressions keeping in view the requirement of the speed of computation. The limitations of the empirical expressions have been pointed out and possible approaches of their improvement have been d...

  17. OPTICAL COMPUTING: Analysis of the tomographic contrast during the immersion bleaching of layered biological tissues

    Prokhorov, I. V.; Yarovenko, I. P.

    2010-01-01

    The control of optical properties of biological tissues irradiated by a cw laser source is considered. Within the framework of the stationary model of the radiation transfer, basic factors affecting the tomographic contrast of a layered medium are revealed theoretically and numerically, when immersion liquids, decreasing the radiation scattering level in a medium, are used.

  18. A Computationally-Efficient Kinetic Approach for Gas/Particle Mass Transfer Treatments: Development, Testing, and 3-D Application

    Hu, X.; Zhang, Y.

    2007-05-01

    The Weather Research and Forecast/Chemistry Model (WRF/Chem) that simulates chemistry simultaneously with meteorology has recently been developed for real-time forecasting by the U.S. National Center for Atmospheric Research (NCAR) and National Oceanic & Atmospheric Administration (NOAA). As one of the six air quality models, WRF/Chem with a modal aerosol module has been applied for ozone and PM2.5 ensemble forecasts over eastern North America as part of the 2004 New England Air Quality Study (NEAQS) program (NEAQS-2004). Significant differences exist in the partitioning of volatile species (e.g., ammonium and nitrate) simulated by the six models. Model biases are partially attributed to the equilibrium assumption used in the gas/particles mass transfer approach in some models. Development of a more accurate, yet computationally- efficient gas/particle mass transfer approach for three-dimensional (3-D) applications, in particular, real-time forecasting, is therefore warranted. Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID) has been implemented into WRF/Chem (referred to as WRF/Chem-MADRID). WRF/Chem-MADRID offers three gas/particle partitioning treatments: equilibrium, kinetic, and hybrid approaches. The equilibrium approach is computationally-efficient and commonly used in 3-D air quality models but less accurate under certain conditions (e.g., in the presence of coarse, reactive particles such as PM containing sea-salts in the coastal areas). The kinetic approach is accurate but computationally-expensive, limiting its 3-D applications. The hybrid approach attempts to provide a compromise between merits and drawbacks of the two approaches by treating fine PM (typically MADRID has recently been developed for 3-D applications based on an Analytical Predictor of Condensation (referred to as kinetic/APC). In this study, WRF/Chem-MADRID with the kinetic/APC approach will be further evaluated along with the equilibrium and hybrid approaches

  19. Micro-computed tomography image-based evaluation of 3D anisotropy degree of polymer scaffolds.

    Pérez-Ramírez, Ursula; López-Orive, Jesús Javier; Arana, Estanislao; Salmerón-Sánchez, Manuel; Moratal, David

    2015-01-01

    Anisotropy is one of the most meaningful determinants of biomechanical behaviour. This study employs micro-computed tomography (μCT) and image techniques for analysing the anisotropy of regenerative medicine polymer scaffolds. For this purpose, three three-dimensional anisotropy evaluation image methods were used: ellipsoid of inertia (EI), mean intercept length (MIL) and tensor scale (t-scale). These were applied to three patterns (a sphere, a cube and a right prism) and to two polymer scaffold topologies (cylindrical orthogonal pore mesh and spherical pores). For the patterns, the three methods provided good results. Regarding the scaffolds, EI mistook both topologies (0.0158, [-0.5683; 0.6001]; mean difference and 95% confidence interval), and MIL showed no significant differences (0.3509, [0.0656; 0.6362]). T-scale is the preferable method because it gave the best capability (0.3441, [0.1779; 0.5102]) to differentiate both topologies. This methodology results in the development of non-destructive tools to engineer biomimetic scaffolds, incorporating anisotropy as a fundamental property to be mimicked from the original tissue and permitting its assessment by means of μCT image analysis.

  20. 3-D computational method of wave loads on turret moored FPSO tankers

    REN Hui-long; ZHANG Hai-bin; DAI Yu-zhi; SONG Jing-zheng

    2003-01-01

    A three-dimensional method of calculating wave loads of turret moored FPSO (Floating Production Storage and Offloading) tankers is presented. The linearized restoring forces acting on the ship hull by the mooring system are calculated according to the catenary theory, which are expressed as the function of linear stiffness coefficients and the displacements of the upper ends of mooring chains. The hydrodynamic coefficients of the ship are calculated by the three-dimensional potential flow theory of the linear hydrodynamic problem for ships with a low forward speed. The equations of ship motions are established with the effect of the restoring forces from the mooring system included as linear stiffness coefficients. The equations of motions are solved in frequency domain, and the responses of wave-induced motions and loads on the ship can be obtained. A computer program based on this method has been developed,and some calculation examples are illustrated. Analysis results show that the method can give satisfying prediction of wave loads.

  1. Computer Tomography 3-D Imaging of the Metal Deformation Flow Path in Friction Stir Welding

    Schneider, Judy; Beshears, Ronald; Nunes, Arthur C., Jr.

    2004-01-01

    In friction stir welding, a rotating threaded pin tool is inserted into a weld seam and literally stirs the edges of the seam together. This solid-state technique has been successfully used in the joining of materials that are difficult to fusion weld such as aluminum alloys. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path is required. Marker studies are the principal method of studying the metal deformation flow path around the FSW pin tool. In our study, we have used computed tomography (CT) scans to reveal the flow pattern of a lead wire embedded in a FSW weld seam. At the welding temperature of aluminum, the lead becomes molten and thus tracks the aluminum deformation flow paths in a unique 3-dimensional manner. CT scanning is a convenient and comprehensive way of collecting and displaying tracer data. It marks an advance over previous more tedious and ambiguous radiographic/metallographic data collection methods.

  2. Scanning laser optical computed tomography system for large volume 3D dosimetry

    Dekker, Kurtis H.; Battista, Jerry J.; Jordan, Kevin J.

    2017-04-01

    Stray light causes artifacts in optical computed tomography (CT) that negatively affect the accuracy of radiation dosimetry in gels or solids. Scatter effects are exacerbated by a large dosimeter volume, which is desirable for direct verification of modern radiotherapy treatment plans such as multiple-isocenter radiosurgery. The goal in this study was to design and characterize an optical CT system that achieves high accuracy primary transmission measurements through effective stray light rejection, while maintaining sufficient scan speed for practical application. We present an optical imaging platform that uses a galvanometer mirror for horizontal scanning, and a translation stage for vertical movement of a laser beam and small area detector for minimal stray light production and acceptance. This is coupled with a custom lens-shaped optical CT aquarium for parallel ray sampling of projections. The scanner images 15 cm diameter, 12 cm height cylindrical volumes at 0.33 mm resolution in approximately 30 min. Attenuation coefficients reconstructed from CT scans agreed with independent cuvette measurements within 2% for both absorbing and scattering solutions as well as small 1.25 cm diameter absorbing phantoms placed within a large, scattering medium that mimics gel. Excellent linearity between the optical CT scanner and the independent measurement was observed for solutions with between 90% and 2% transmission. These results indicate that the scanner should achieve highly accurate dosimetry of large volume dosimeters in a reasonable timeframe for clinical application to radiotherapy dose verification procedures.

  3. Scanning laser optical computed tomography system for large volume 3D dosimetry.

    Dekker, Kurtis H; Battista, Jerry J; Jordan, Kevin J

    2017-04-07

    Stray light causes artifacts in optical computed tomography (CT) that negatively affect the accuracy of radiation dosimetry in gels or solids. Scatter effects are exacerbated by a large dosimeter volume, which is desirable for direct verification of modern radiotherapy treatment plans such as multiple-isocenter radiosurgery. The goal in this study was to design and characterize an optical CT system that achieves high accuracy primary transmission measurements through effective stray light rejection, while maintaining sufficient scan speed for practical application. We present an optical imaging platform that uses a galvanometer mirror for horizontal scanning, and a translation stage for vertical movement of a laser beam and small area detector for minimal stray light production and acceptance. This is coupled with a custom lens-shaped optical CT aquarium for parallel ray sampling of projections. The scanner images 15 cm diameter, 12 cm height cylindrical volumes at 0.33 mm resolution in approximately 30 min. Attenuation coefficients reconstructed from CT scans agreed with independent cuvette measurements within 2% for both absorbing and scattering solutions as well as small 1.25 cm diameter absorbing phantoms placed within a large, scattering medium that mimics gel. Excellent linearity between the optical CT scanner and the independent measurement was observed for solutions with between 90% and 2% transmission. These results indicate that the scanner should achieve highly accurate dosimetry of large volume dosimeters in a reasonable timeframe for clinical application to radiotherapy dose verification procedures.

  4. Quantification of arthritic bone degradation by analysis of 3D micro-computed tomography data

    Svensson, Carl-Magnus; Hoffmann, Bianca; Irmler, Ingo M.; Straßburger, Maria; Figge, Marc Thilo; Saluz, Hans Peter

    2017-01-01

    The use of animal models of arthritis is a key component in the evaluation of therapeutic strategies against the human disease rheumatoid arthritis (RA). Here we present quantitative measurements of bone degradation characterised by the cortical bone profile using glucose-6-phosphate isomerase (G6PI) induced arthritis. We applied micro-computed tomography (μCT) during three arthritis experiments and one control experiment to image the metatarsals of the hind paws and to investigate the effect of experimental arthritis on their cortical bone profile. For measurements of the cortical profile we automatically identified slices that are orthogonal to individual metatarsals, thereby making the measurements independent of animal placement in the scanner. We measured the average cortical thickness index (CTI) of the metatarsals, as well as the thickness changes along the metatarsal. In this study we introduced the cortical thickness gradient (CTG) as a new measure and we investigated how arthritis affects this measure. We found that in general both CTI and CTG are able to quantify arthritic progression, whilst CTG was found to be the more sensitive measure. PMID:28290525

  5. Effects of Electrode Position on Spatiotemporal Auditory Nerve Fiber Responses: A 3D Computational Model Study

    Soojin Kang

    2015-01-01

    Full Text Available A cochlear implant (CI is an auditory prosthesis that enables hearing by providing electrical stimuli through an electrode array. It has been previously established that the electrode position can influence CI performance. Thus, electrode position should be considered in order to achieve better CI results. This paper describes how the electrode position influences the auditory nerve fiber (ANF response to either a single pulse or low- (250 pulses/s and high-rate (5,000 pulses/s pulse-trains using a computational model. The field potential in the cochlea was calculated using a three-dimensional finite-element model, and the ANF response was simulated using a biophysical ANF model. The effects were evaluated in terms of the dynamic range, stochasticity, and spike excitation pattern. The relative spread, threshold, jitter, and initiated node were analyzed for single-pulse response; and the dynamic range, threshold, initiated node, and interspike interval were analyzed for pulse-train stimuli responses. Electrode position was found to significantly affect the spatiotemporal pattern of the ANF response, and this effect was significantly dependent on the stimulus rate. We believe that these modeling results can provide guidance regarding perimodiolar and lateral insertion of CIs in clinical settings and help understand CI performance.

  6. Complex anatomy surrounding the left atrial posterior wall: analysis with 3D computed tomography.

    Maeda, Shingo; Iesaka, Yoshito; Uno, Kikuya; Otomo, Kiyoshi; Nagata, Yasutoshi; Suzuki, Kenji; Hachiya, Hitoshi; Goya, Masahiko; Takahashi, Atsushi; Fujiwara, Hideomi; Hiraoka, Masayasu; Isobe, Mitsuaki

    2012-01-01

    Few studies have explored the topographic anatomy of the esophagus, posterior wall of the left atrium (LA), or fat pads using multidetector computed tomography (MDCT) to prevent the risk of esophageal injury during atrial fibrillation (AF) ablation. MDCT was performed in 110 consecutive patients with paroxysmal or persistent AF before the ablation procedure to understand the anatomic relationship of the esophagus. Two major types of esophagus routes were demonstrated. Leftward (type A) and rightward (type B) routes were found in 90 and 10% of the patients, respectively. A type A route had a larger mean size of the LA than type B. The fat pad was identifiable at the level of the inferior pulmonary vein in 91% of the patients without any predominance of either type. The thickness of the fat pad was thinner in the patients with a dilated LA (>42 mm) than in those with a normal LA size (≤42 mm) (p = 0.01). The results demonstrated that the majority of cases had a leftward route of the esophagus. There was a close association between the LA dilatation and fat pad thinning. With a dilated LA, the esophagus may become easily susceptible to direct thermal injury during AF ablation. Visualization of the anatomic relationship may contribute to the prevention of the potential risk of an esophageal injury.

  7. Voxelization Algorithms for Geospatial Applications: Computational methods for voxelating spatial datasets of 3D city models containing 3D surface, curve and point data models

    Nourian Ghadikolaee, P.; Goncalves, R.; Zlatanova, S.; Arroyo Ohori, G.A.K.; Vu Vo, A.

    2016-01-01

    Voxel representations have been used for years in scientific computation and medical imaging. The main focus of our research is to provide easy access to methods for making large-scale voxel models of built environment for environmental modelling studies while ensuring they are spatially correct, me

  8. Effects of computing parameters and measurement locations on the estimation of 3D NPS in non-stationary MDCT images.

    Miéville, Frédéric A; Bolard, Gregory; Bulling, Shelley; Gudinchet, François; Bochud, François O; Verdun, François R

    2013-11-01

    The goal of this study was to investigate the impact of computing parameters and the location of volumes of interest (VOI) on the calculation of 3D noise power spectrum (NPS) in order to determine an optimal set of computing parameters and propose a robust method for evaluating the noise properties of imaging systems. Noise stationarity in noise volumes acquired with a water phantom on a 128-MDCT and a 320-MDCT scanner were analyzed in the spatial domain in order to define locally stationary VOIs. The influence of the computing parameters in the 3D NPS measurement: the sampling distances bx,y,z and the VOI lengths Lx,y,z, the number of VOIs NVOI and the structured noise were investigated to minimize measurement errors. The effect of the VOI locations on the NPS was also investigated. Results showed that the noise (standard deviation) varies more in the r-direction (phantom radius) than z-direction plane. A 25 × 25 × 40 mm(3) VOI associated with DFOV = 200 mm (Lx,y,z = 64, bx,y = 0.391 mm with 512 × 512 matrix) and a first-order detrending method to reduce structured noise led to an accurate NPS estimation. NPS estimated from off centered small VOIs had a directional dependency contrary to NPS obtained from large VOIs located in the center of the volume or from small VOIs located on a concentric circle. This showed that the VOI size and location play a major role in the determination of NPS when images are not stationary. This study emphasizes the need for consistent measurement methods to assess and compare image quality in CT.

  9. Pipelining Computational Stages of the Tomographic Reconstructor for Multi-Object Adaptive Optics on a Multi-GPU System

    Charara, Ali

    2014-11-01

    The European Extremely Large Telescope project (E-ELT) is one of Europe\\'s highest priorities in ground-based astronomy. ELTs are built on top of a variety of highly sensitive and critical astronomical instruments. In particular, a new instrument called MOSAIC has been proposed to perform multi-object spectroscopy using the Multi-Object Adaptive Optics (MOAO) technique. The core implementation of the simulation lies in the intensive computation of a tomographic reconstruct or (TR), which is used to drive the deformable mirror in real time from the measurements. A new numerical algorithm is proposed (1) to capture the actual experimental noise and (2) to substantially speed up previous implementations by exposing more concurrency, while reducing the number of floating-point operations. Based on the Matrices Over Runtime System at Exascale numerical library (MORSE), a dynamic scheduler drives all computational stages of the tomographic reconstruct or simulation and allows to pipeline and to run tasks out-of order across different stages on heterogeneous systems, while ensuring data coherency and dependencies. The proposed TR simulation outperforms asymptotically previous state-of-the-art implementations up to 13-fold speedup. At more than 50000 unknowns, this appears to be the largest-scale AO problem submitted to computation, to date, and opens new research directions for extreme scale AO simulations. © 2014 IEEE.

  10. Petrophysical analysis of limestone rocks by nuclear logging and 3D high-resolution X-ray computed microtomography

    Oliveira, M.F.S. [Nuclear Instrumentation Laboratory, COPPE-PEN, UFRJ, P.O. Box 68509, 21941-972 Rio de Janeiro, RJ (Brazil); Lima, I., E-mail: inaya@lin.ufrj.br [Nuclear Instrumentation Laboratory, COPPE-PEN, UFRJ, P.O. Box 68509, 21941-972 Rio de Janeiro, RJ (Brazil); Department of Mechanical Engineering and Energy, IPRJ-UERJ, Nova Friburgo, RJ (Brazil); Ferrucio, P.L.; Abreu, C.J.; Borghi, L. [Geology Department, Geosciences Institute, Rio de Janeiro Federal University, Rio de Janeiro, RJ (Brazil); Lopes, R.T. [Nuclear Instrumentation Laboratory, COPPE-PEN, UFRJ, P.O. Box 68509, 21941-972 Rio de Janeiro, RJ (Brazil)

    2011-10-01

    This study presents the pore-space system analysis of the 2-ITAB-1-RJ well cores, which were drilled in the Sao Jose do Itaborai Basin, in the state of Rio de Janeiro, Brasil. The analysis presented herein has been developed based on two techniques: nuclear logging and 3D high-resolution X-ray computed microtomography. Nuclear logging has been proven to be the technique that provides better quality and more quantitative information about the porosity using radioactive sources. The Density Gamma Probe and the Neutron Sonde used in this work provide qualitative information about bulk density variations and compensated porosity of the geological formation. The samples obtained from the well cores were analyzed by microtomography. The use of this technique in sedimentary rocks allows quantitative evaluation of pore system and generates high-resolution 3D images ({approx}microns order). The images and data obtained by microtomography were integrated with the response obtained by nuclear logging. The results obtained by these two techniques allow the understanding of the pore-size distribution and connectivity, as well as the porosity values. Both techniques are important and they complement each other.

  11. Computational Fluid Dynamic Analyses for the High-Lift Common Research Model Using the USM3D and FUN3D Flow Solvers

    Rivers, Melissa; Hunter, Craig; Vatsa, Veer

    2017-01-01

    Two Navier-Stokes codes were used to compute flow over the High-Lift Common Research Model (HL-CRM) in preparation for a wind tunnel test to be performed at the NASA Langley Research Center 14-by-22-Foot Subsonic Tunnel in fiscal year 2018. Both flight and wind tunnel conditions were simulated by the two codes at set Mach numbers and Reynolds numbers over a full angle-of-attack range for three configurations: cruise, landing and takeoff. Force curves, drag polars and surface pressure contour comparisons are shown for the two codes. The lift and drag curves compare well for the cruise configuration up to 10deg angle of attack but not as well for the other two configurations. The drag polars compare reasonably well for all three configurations. The surface pressure contours compare well for some of the conditions modeled but not as well for others.

  12. Three-dimensional helical computed tomographic evaluation of three obturation techniques: In vitro study

    M Chokkalingam

    2011-01-01

    Full Text Available Aim: The purpose of this study was to evaluate the adequacy of three obturation techniques namely lateral condensation, EQ Fil (backfill obturation and thermafil (core carrier obturation techniques using three-dimensional (3D helical computed tomography (CT by volume rendering method. Materials and Methods: Thirty freshly extracted teeth were randomly divided into three groups of 10 teeth each. Biomechanical preparation was done in all the teeth using rotary instruments. All three sets of teeth were placed in helical CT slice scanner and were imaged before obturation. The three sets were then obturated by following methods: Group I: lateral condensation, Group II: EQ Fil (backfill and Group III: thermafil (core carrier obturation.Volume of the pulp chamber and gutta-percha after obturation were calculated using volume rendering technique and adequacy of the obturation techniques were calculated. Statistical Analysis Used: One-way ANOVA and Multiple-Range Tukey Test by Tukey-HSD procedure Results: Mean change in lateral condensation (0.005±0.002 was significantly higher than that of thermafil obturation (0.002±0.001 [P<0.05]. Conclusions: Conventional lateral condensation technique showed maximal inadequacy of obturation and thermafil obturation technique showed the least inadequacy of obturation when the volume of the specimens were calculated and reconstructed

  13. Numerical study for the calculation of computer-generated hologram in color holographic 3D projection enabled by modified wavefront recording plane method

    Chang, Chenliang; Qi, Yijun; Wu, Jun; Yuan, Caojin; Nie, Shouping; Xia, Jun

    2017-03-01

    A method of calculating computer-generated hologram (CGH) for color holographic 3D projection is proposed. A color 3D object is decomposed into red, green and blue components. For each color component, a virtual wavefront recording plane (WRP) is established which is nonuniformly sampled according to the depth map of the 3D object. The hologram of each color component is calculated from the nonuniform sampled WRP using the shifted Fresnel diffraction algorithm. Finally three holograms of RGB components are encoded into one single CGH based on the multiplexing encoding method. The computational cost of CGH generation is reduced by converting diffraction calculation from huge 3D voxels to three 2D planar images. Numerical experimental results show that the CGH generated by our method is capable to project zoomable color 3D object with clear quality.

  14. Steady-State VEP-Based Brain-Computer Interface Control in an Immersive 3D Gaming Environment

    Burke R

    2005-01-01

    Full Text Available This paper presents the application of an effective EEG-based brain-computer interface design for binary control in a visually elaborate immersive 3D game. The BCI uses the steady-state visual evoked potential (SSVEP generated in response to phase-reversing checkerboard patterns. Two power-spectrum estimation methods were employed for feature extraction in a series of offline classification tests. Both methods were also implemented during real-time game play. The performance of the BCI was found to be robust to distracting visual stimulation in the game and relatively consistent across six subjects, with 41 of 48 games successfully completed. For the best performing feature extraction method, the average real-time control accuracy across subjects was 89%. The feasibility of obtaining reliable control in such a visually rich environment using SSVEPs is thus demonstrated and the impact of this result is discussed.

  15. Steady-State VEP-Based Brain-Computer Interface Control in an Immersive 3D Gaming Environment

    Lalor, E. C.; Kelly, S. P.; Finucane, C.; Burke, R.; Smith, R.; Reilly, R. B.; McDarby, G.

    2005-12-01

    This paper presents the application of an effective EEG-based brain-computer interface design for binary control in a visually elaborate immersive 3D game. The BCI uses the steady-state visual evoked potential (SSVEP) generated in response to phase-reversing checkerboard patterns. Two power-spectrum estimation methods were employed for feature extraction in a series of offline classification tests. Both methods were also implemented during real-time game play. The performance of the BCI was found to be robust to distracting visual stimulation in the game and relatively consistent across six subjects, with 41 of 48 games successfully completed. For the best performing feature extraction method, the average real-time control accuracy across subjects was 89%. The feasibility of obtaining reliable control in such a visually rich environment using SSVEPs is thus demonstrated and the impact of this result is discussed.

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

    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.

  17. Voxelization algorithms for geospatial applications: Computational methods for voxelating spatial datasets of 3D city models containing 3D surface, curve and point data models.

    Nourian, Pirouz; Gonçalves, Romulo; Zlatanova, Sisi; Ohori, Ken Arroyo; Vu Vo, Anh

    2016-01-01

    Voxel representations have been used for years in scientific computation and medical imaging. The main focus of our research is to provide easy access to methods for making large-scale voxel models of built environment for environmental modelling studies while ensuring they are spatially correct, meaning they correctly represent topological and semantic relations among objects. In this article, we present algorithms that generate voxels (volumetric pixels) out of point cloud, curve, or surface objects. The algorithms for voxelization of surfaces and curves are a customization of the topological voxelization approach [1]; we additionally provide an extension of this method for voxelization of point clouds. The developed software has the following advantages:•It provides easy management of connectivity levels in the resulting voxels.•It is not dependant on any external library except for primitive types and constructs; therefore, it is easy to integrate them in any application.•One of the algorithms is implemented in C++ and C for platform independence and efficiency.

  18. Relative flattening between velvet and matte 3D shapes: Evidence for similar shape-from-shading computations

    Wijntjes, W.A.; Doerschner, K.; Kucukoglu, G.; Pont, S.C.

    2011-01-01

    Among other cues, the visual system uses shading to infer the 3D shape of objects. The shading pattern depends on the illumination and reflectance properties (BRDF). In this study, we compared 3D shape perception between identical shapes with different BRDFs. The stimuli were photographed 3D printed

  19. Modeling warm dense matter experiments using the 3D ALE-AMR code and the move toward exascale computing

    Koniges Alice

    2013-11-01

    Full Text Available The Neutralized Drift Compression Experiment II (NDCX II is an induction accelerator planned for initial commissioning in 2012. The final design calls for a 3 MeV, Li+ ion beam, delivered in a bunch with characteristic pulse duration of 1 ns, and transverse dimension of order 1 mm. The NDCX II will be used in studies of material in the warm dense matter (WDM regime, and ion beam/hydrodynamic coupling experiments relevant to heavy ion based inertial fusion energy. We discuss recent efforts to adapt the 3D ALE-AMR code to model WDM experiments on NDCX II. The code, which combines Arbitrary Lagrangian Eulerian (ALE hydrodynamics with Adaptive Mesh Refinement (AMR, has physics models that include ion deposition, radiation hydrodynamics, thermal diffusion, anisotropic material strength with material time history, and advanced models for fragmentation. Experiments at NDCX-II will explore the process of bubble and droplet formation (two-phase expansion of superheated metal solids using ion beams. Experiments at higher temperatures will explore equation of state and heavy ion fusion beam-to-target energy coupling efficiency. Ion beams allow precise control of local beam energy deposition providing uniform volumetric heating on a timescale shorter than that of hydrodynamic expansion. We also briefly discuss the effects of the move to exascale computing and related computational changes on general modeling codes in fusion.

  20. Computational modeling of pitching cylinder-type ocean wave energy converters using 3D MPI-parallel simulations

    Freniere, Cole; Pathak, Ashish; Raessi, Mehdi

    2016-11-01

    Ocean Wave Energy Converters (WECs) are devices that convert energy from ocean waves into electricity. To aid in the design of WECs, an advanced computational framework has been developed which has advantages over conventional methods. The computational framework simulates the performance of WECs in a virtual wave tank by solving the full Navier-Stokes equations in 3D, capturing the fluid-structure interaction, nonlinear and viscous effects. In this work, we present simulations of the performance of pitching cylinder-type WECs and compare against experimental data. WECs are simulated at both model and full scales. The results are used to determine the role of the Keulegan-Carpenter (KC) number. The KC number is representative of viscous drag behavior on a bluff body in an oscillating flow, and is considered an important indicator of the dynamics of a WEC. Studying the effects of the KC number is important for determining the validity of the Froude scaling and the inviscid potential flow theory, which are heavily relied on in the conventional approaches to modeling WECs. Support from the National Science Foundation is gratefully acknowledged.

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

    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.

  2. Computed tomographic study of 50 patients with hypodense hepatic injuries in childhood; Estudo de 50 casos por tomografia computadorizada de lesoes hipodensas hepaticas fundamentais na infancia

    Pereira, Ines Minniti Rodrigues; Alvares, Beatriz Regina; Baracat, Jamal; Martins, Daniel Lahan [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Ciencias Medicas. Dept. de Radiologia]. E-mail: iminniti@fcm.unicamp.br; Pereira, Ricardo Minniti Rodrigues [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Ciencias Medicas

    2006-03-15

    Objective: To describe the different tomographic findings in hypodense hepatic lesions in children and its differential diagnosis. Materials and methods: computed tomographic studies were obtained from 50 patients (age range: 0-16 years) with low-density liver lesions previously diagnosed by ultrasound. Images were made before and after administration of intravenous contrast medium. Image findings were analyzed and afterwards correlated with anatomopathological diagnosis. Results: forty-seven of 50 cases were confirmed, 30 by anatomopathological diagnosis. Most of then were benign lesions, hemangioma in 20%. Such lesions presented a homogeneous contrast absorption, mainly at the delayed phase, differing from malignant lesions. Metastasis was the most frequently found malignant lesion (18%). Conclusion: computed tomographic study is of great value in complementing the diagnosis of hypodense hepatic lesions in children, and must follow ultrasound diagnosis as a routine procedure. (author)

  3. Enhanced methods for computing spectra from CO5BOLD models using Linfor3D. Molecular bands in metal-poor stars

    Gallagher, A J; Caffau, E; Bonifacio, P; Ludwig, H -G; Freytag, B

    2016-01-01

    Molecular features such as the G-band, CN-band and NH-band are important diagnostics for measuring a star's carbon and nitrogen abundances, especially in metal-poor stars where atomic lines are no longer visible in stellar spectra. Unlike atomic transitions, molecular features tend to form in bands, which cover large wavelength regions in a spectrum. While it is a trivial matter to compute carbon and nitrogen molecular bands under the assumption of 1D, it is extremely time consuming in 3D. In this contribution to the 2016 CO5BOLD workshop we review the improvements made to the 3D spectral synthesis code Linfor3D, and discuss the new challenges found when computing molecular features in 3D.

  4. A Real-Time Magnetoencephalography Brain-Computer Interface Using Interactive 3D Visualization and the Hadoop Ecosystem

    McClay, Wilbert A.; Yadav, Nancy; Ozbek, Yusuf; Haas, Andy; Attias, Hagaii T.; Nagarajan, Srikantan S.

    2015-01-01

    Ecumenically, the fastest growing segment of Big Data is human biology-related data and the annual data creation is on the order of zetabytes. The implications are global across industries, of which the treatment of brain related illnesses and trauma could see the most significant and immediate effects. The next generation of health care IT and sensory devices are acquiring and storing massive amounts of patient related data. An innovative Brain-Computer Interface (BCI) for interactive 3D visualization is presented utilizing the Hadoop Ecosystem for data analysis and storage. The BCI is an implementation of Bayesian factor analysis algorithms that can distinguish distinct thought actions using magneto encephalographic (MEG) brain signals. We have collected data on five subjects yielding 90% positive performance in MEG mid- and post-movement activity. We describe a driver that substitutes the actions of the BCI as mouse button presses for real-time use in visual simulations. This process has been added into a flight visualization demonstration. By thinking left or right, the user experiences the aircraft turning in the chosen direction. The driver components of the BCI can be compiled into any software and substitute a user’s intent for specific keyboard strikes or mouse button presses. The BCI’s data analytics of a subject’s MEG brainwaves and flight visualization performance are stored and analyzed using the Hadoop Ecosystem as a quick retrieval data warehouse. PMID:26437432

  5. Rational Design of Prevascularized Large 3D Tissue Constructs Using Computational Simulations and Biofabrication of Geometrically Controlled Microvessels.

    Arrigoni, Chiara; Bongio, Matilde; Talò, Giuseppe; Bersini, Simone; Enomoto, Junko; Fukuda, Junji; Moretti, Matteo

    2016-07-01

    A major challenge in the development of clinically relevant 3D tissue constructs is the formation of vascular networks for oxygenation, nutrient supply, and waste removal. To this end, this study implements a multimodal approach for the promotion of vessel-like structures formation in stiff fibrin hydrogels. Computational simulations have been performed to identify the easiest microchanneled configuration assuring normoxic conditions throughout thick cylindrical hydrogels (8 mm height, 6 mm ∅), showing that in our configuration a minimum of three microchannels (600 μm ∅), placed in a non-planar disposition, is required. Using small hydrogel bricks with oxygen distribution equal to the microchanneled configuration, this study demonstrates that among different culture conditions, co-culture of mesenchymal and endothelial cells supplemented with ANG-1 and VEGF leads to the most developed vascular network. Microchanneled hydrogels have been then cultured in the same conditions both statically and in a bioreactor for 7 d. Unexpectedly, the combination between shear forces and normoxic conditions is unable to promote microvascular networks formation in three-channeled hydrogels. Differently, application of either shear forces or normoxic conditions alone results in microvessels outgrowth. These results suggest that to induce angiogenesis in engineered constructs, complex interactions between several biochemical and biophysical parameters have to be modulated.

  6. A Real-Time Magnetoencephalography Brain-Computer Interface Using Interactive 3D Visualization and the Hadoop Ecosystem.

    McClay, Wilbert A; Yadav, Nancy; Ozbek, Yusuf; Haas, Andy; Attias, Hagaii T; Nagarajan, Srikantan S

    2015-09-30

    Ecumenically, the fastest growing segment of Big Data is human biology-related data and the annual data creation is on the order of zetabytes. The implications are global across industries, of which the treatment of brain related illnesses and trauma could see the most significant and immediate effects. The next generation of health care IT and sensory devices are acquiring and storing massive amounts of patient related data. An innovative Brain-Computer Interface (BCI) for interactive 3D visualization is presented utilizing the Hadoop Ecosystem for data analysis and storage. The BCI is an implementation of Bayesian factor analysis algorithms that can distinguish distinct thought actions using magneto encephalographic (MEG) brain signals. We have collected data on five subjects yielding 90% positive performance in MEG mid- and post-movement activity. We describe a driver that substitutes the actions of the BCI as mouse button presses for real-time use in visual simulations. This process has been added into a flight visualization demonstration. By thinking left or right, the user experiences the aircraft turning in the chosen direction. The driver components of the BCI can be compiled into any software and substitute a user's intent for specific keyboard strikes or mouse button presses. The BCI's data analytics OPEN ACCESS Brain. Sci. 2015, 5 420 of a subject's MEG brainwaves and flight visualization performance are stored and analyzed using the Hadoop Ecosystem as a quick retrieval data warehouse.

  7. A Real-Time Magnetoencephalography Brain-Computer Interface Using Interactive 3D Visualization and the Hadoop Ecosystem

    Wilbert A. McClay

    2015-09-01

    Full Text Available Ecumenically, the fastest growing segment of Big Data is human biology-related data and the annual data creation is on the order of zetabytes. The implications are global across industries, of which the treatment of brain related illnesses and trauma could see the most significant and immediate effects. The next generation of health care IT and sensory devices are acquiring and storing massive amounts of patient related data. An innovative Brain-Computer Interface (BCI for interactive 3D visualization is presented utilizing the Hadoop Ecosystem for data analysis and storage. The BCI is an implementation of Bayesian factor analysis algorithms that can distinguish distinct thought actions using magneto encephalographic (MEG brain signals. We have collected data on five subjects yielding 90% positive performance in MEG mid- and post-movement activity. We describe a driver that substitutes the actions of the BCI as mouse button presses for real-time use in visual simulations. This process has been added into a flight visualization demonstration. By thinking left or right, the user experiences the aircraft turning in the chosen direction. The driver components of the BCI can be compiled into any software and substitute a user’s intent for specific keyboard strikes or mouse button presses. The BCI’s data analytics OPEN ACCESS Brain. Sci. 2015, 5 420 of a subject’s MEG brainwaves and flight visualization performance are stored and analyzed using the Hadoop Ecosystem as a quick retrieval data warehouse.

  8. Computed Tomography Image Origin Identification based on Original Sensor Pattern Noise and 3D Image Reconstruction Algorithm Footprints.

    Duan, Yuping; Bouslimi, Dalel; Yang, Guanyu; Shu, Huazhong; Coatrieux, Gouenou

    2016-06-08

    In this paper, we focus on the "blind" identification of the Computed Tomography (CT) scanner that has produced a CT image. To do so, we propose a set of noise features derived from the image chain acquisition and which can be used as CT-Scanner footprint. Basically, we propose two approaches. The first one aims at identifying a CT-Scanner based on an Original Sensor Pattern Noise (OSPN) that is intrinsic to the X-ray detectors. The second one identifies an acquisition system based on the way this noise is modified by its 3D image reconstruction algorithm. As these reconstruction algorithms are manufacturer dependent and kept secret, our features are used as input to train an SVM based classifier so as to discriminate acquisition systems. Experiments conducted on images issued from 15 different CT-Scanner models of 4 distinct manufacturers demonstrate that our system identifies the origin of one CT image with a detection rate of at least 94% and that it achieves better performance than Sensor Pattern Noise (SPN) based strategy proposed for general public camera devices.

  9. Rapid Reconstitution Packages (RRPs) implemented by integration of computational fluid dynamics (CFD) and 3D printed microfluidics.

    Chi, Albert; Curi, Sebastian; Clayton, Kevin; Luciano, David; Klauber, Kameron; Alexander-Katz, Alfredo; D'hers, Sebastian; Elman, Noel M

    2014-08-01

    Rapid Reconstitution Packages (RRPs) are portable platforms that integrate microfluidics for rapid reconstitution of lyophilized drugs. Rapid reconstitution of lyophilized drugs using standard vials and syringes is an error-prone process. RRPs were designed using computational fluid dynamics (CFD) techniques to optimize fluidic structures for rapid mixing and integrating physical properties of targeted drugs and diluents. Devices were manufactured using stereo lithography 3D printing for micrometer structural precision and rapid prototyping. Tissue plasminogen activator (tPA) was selected as the initial model drug to test the RRPs as it is unstable in solution. tPA is a thrombolytic drug, stored in lyophilized form, required in emergency settings for which rapid reconstitution is of critical importance. RRP performance and drug stability were evaluated by high-performance liquid chromatography (HPLC) to characterize release kinetics. In addition, enzyme-linked immunosorbent assays (ELISAs) were performed to test for drug activity after the RRPs were exposed to various controlled temperature conditions. Experimental results showed that RRPs provided effective reconstitution of tPA that strongly correlated with CFD results. Simulation and experimental results show that release kinetics can be adjusted by tuning the device structural dimensions and diluent drug physical parameters. The design of RRPs can be tailored for a number of applications by taking into account physical parameters of the active pharmaceutical ingredients (APIs), excipients, and diluents. RRPs are portable platforms that can be utilized for reconstitution of emergency drugs in time-critical therapies.

  10. Bayesian 3D X-ray computed tomography image reconstruction with a scaled Gaussian mixture prior model

    Wang, Li; Gac, Nicolas; Mohammad-Djafari, Ali

    2015-01-01

    In order to improve quality of 3D X-ray tomography reconstruction for Non Destructive Testing (NDT), we investigate in this paper hierarchical Bayesian methods. In NDT, useful prior information on the volume like the limited number of materials or the presence of homogeneous area can be included in the iterative reconstruction algorithms. In hierarchical Bayesian methods, not only the volume is estimated thanks to the prior model of the volume but also the hyper parameters of this prior. This additional complexity in the reconstruction methods when applied to large volumes (from 5123 to 81923 voxels) results in an increasing computational cost. To reduce it, the hierarchical Bayesian methods investigated in this paper lead to an algorithm acceleration by Variational Bayesian Approximation (VBA) [1] and hardware acceleration thanks to projection and back-projection operators paralleled on many core processors like GPU [2]. In this paper, we will consider a Student-t prior on the gradient of the image implemented in a hierarchical way [3, 4, 1]. Operators H (forward or projection) and Ht (adjoint or back-projection) implanted in multi-GPU [2] have been used in this study. Different methods will be evalued on synthetic volume "Shepp and Logan" in terms of quality and time of reconstruction. We used several simple regularizations of order 1 and order 2. Other prior models also exists [5]. Sometimes for a discrete image, we can do the segmentation and reconstruction at the same time, then the reconstruction can be done with less projections.

  11. The 3D MHD code GOEMHD3 for astrophysical plasmas with large Reynolds numbers. Code description, verification, and computational performance

    Skála, J.; Baruffa, F.; Büchner, J.; Rampp, M.

    2015-08-01

    Context. The numerical simulation of turbulence and flows in almost ideal astrophysical plasmas with large Reynolds numbers motivates the implementation of magnetohydrodynamical (MHD) computer codes with low resistivity. They need to be computationally efficient and scale well with large numbers of CPU cores, allow obtaining a high grid resolution over large simulation domains, and be easily and modularly extensible, for instance, to new initial and boundary conditions. Aims: Our aims are the implementation, optimization, and verification of a computationally efficient, highly scalable, and easily extensible low-dissipative MHD simulation code for the numerical investigation of the dynamics of astrophysical plasmas with large Reynolds numbers in three dimensions (3D). Methods: The new GOEMHD3 code discretizes the ideal part of the MHD equations using a fast and efficient leap-frog scheme that is second-order accurate in space and time and whose initial and boundary conditions can easily be modified. For the investigation of diffusive and dissipative processes the corresponding terms are discretized by a DuFort-Frankel scheme. To always fulfill the Courant-Friedrichs-Lewy stability criterion, the time step of the code is adapted dynamically. Numerically induced local oscillations are suppressed by explicit, externally controlled diffusion terms. Non-equidistant grids are implemented, which enhance the spatial resolution, where needed. GOEMHD3 is parallelized based on the hybrid MPI-OpenMP programing paradigm, adopting a standard two-dimensional domain-decomposition approach. Results: The ideal part of the equation solver is verified by performing numerical tests of the evolution of the well-understood Kelvin-Helmholtz instability and of Orszag-Tang vortices. The accuracy of solving the (resistive) induction equation is tested by simulating the decay of a cylindrical current column. Furthermore, we show that the computational performance of the code scales very

  12. GRID2D/3D: A computer program for generating grid systems in complex-shaped two- and three-dimensional spatial domains. Part 1: Theory and method

    Shih, T. I.-P.; Bailey, R. T.; Nguyen, H. L.; Roelke, R. J.

    1990-01-01

    An efficient computer program, called GRID2D/3D was developed to generate single and composite grid systems within geometrically complex two- and three-dimensional (2- and 3-D) spatial domains that can deform with time. GRID2D/3D generates single grid systems by using algebraic grid generation methods based on transfinite interpolation in which the distribution of grid points within the spatial domain is controlled by stretching functions. All single grid systems generated by GRID2D/3D can have grid lines that are continuous and differentiable everywhere up to the second-order. Also, grid lines can intersect boundaries of the spatial domain orthogonally. GRID2D/3D generates composite grid systems by patching together two or more single grid systems. The patching can be discontinuous or continuous. For continuous composite grid systems, the grid lines are continuous and differentiable everywhere up to the second-order except at interfaces where different single grid systems meet. At interfaces where different single grid systems meet, the grid lines are only differentiable up to the first-order. For 2-D spatial domains, the boundary curves are described by using either cubic or tension spline interpolation. For 3-D spatial domains, the boundary surfaces are described by using either linear Coon's interpolation, bi-hyperbolic spline interpolation, or a new technique referred to as 3-D bi-directional Hermite interpolation. Since grid systems generated by algebraic methods can have grid lines that overlap one another, GRID2D/3D contains a graphics package for evaluating the grid systems generated. With the graphics package, the user can generate grid systems in an interactive manner with the grid generation part of GRID2D/3D. GRID2D/3D is written in FORTRAN 77 and can be run on any IBM PC, XT, or AT compatible computer. In order to use GRID2D/3D on workstations or mainframe computers, some minor modifications must be made in the graphics part of the program; no

  13. Examining the effect of pore size distribution and shape on flow through unsaturated peat using 3-D computed tomography

    F. Rezanezhad

    2009-05-01

    Full Text Available The hydraulic conductivity of unsaturated peat soils is controlled by the peat structure which affects the air-filled porosity, pore size distribution and shape. This study investigates how the size and shape of pores affects the flow of water through peat soils. In this study we used X-ray Computed Tomography (CT, at 45 µm resolution under 5 specific soil-water pressure head levels to provide 3-D, high-resolution images that were used to detect the inner pore structure of peat samples under a changing water regime. Pore structure and configuration were found to be irregular, which affected the rate of water transmission through peat soils. The 3-D analysis suggested that pore distribution is dominated by a single large pore-space. At low pressure head, this single large air-filled pore imparted a more effective flowpath compared to smaller pores. Smaller pores were disconnected and the flowpath was more tortuous than in the single large air-filled pore, and their contribution to flow was negligible when the single large pore was active. We quantify the pore structure of peat soil that affects the hydraulic conductivity in the unsaturated condition, and demonstrate the validity of our estimation of peat unsaturated hydraulic conductivity by making a comparison with a standard permeameter-based method. Estimates of unsaturated hydraulic conductivities were made for the purpose of testing the sensitivity of pore shape and geometry parameters on the hydraulic properties of peats and how to evaluate the structure of the peat and its affects on parameterization. We also studied the ability to quantify these factors for different soil moisture contents in order to define how the factors controlling the shape coefficient vary with changes in soil water pressure head. The relation between measured and estimated unsaturated hydraulic conductivity at various heads shows that rapid initial drainage, that changes the air-filled pore properties, creates a

  14. Coronary computed tomography angiography with 320-row detector and using the AIDR-3D: initial experience; Angiotomografia computadorizada de coronarias com tomografo com 320 fileiras de detectores e utilizando o AIDR-3D: experiencia inicial

    Sasdelli Neto, Roberto; Nomura, Cesar Higa; Macedo, Ana Carolina Sandoval; Bianco, Danilo Perussi; Kay, Fernando Uliana; Szarf, Gilberto; Teles, Gustavo Borges da Silva; Shoji, Hamilton; Santana Netto, Pedro Vieira; Passos, Rodrigo Bastos Duarte; Chate, Rodrigo Caruso; Ishikawa, Walther Yoshiharu; Lima, Joao Paulo Bacellar Costa; Rocha, Marcelo Assis; Marcos, Vinicius Neves; Funari, Marcelo Buarque de Gusmao, E-mail: roberto.neto@einstein.br [Hospital Israelita Albert Einstein, Sao Paulo, SP (Brazil); Failla, Bruna Bonaventura [Universidade Metodista de Sao Paulo, Sao Bernardo do Campo, SP (Brazil)

    2013-07-01

    Coronary computed tomography angiography (coronary CTA) is a powerful non-invasive imaging method to evaluate coronary artery disease. Nowadays, coronary CTA estimated effective radiation dose can be dramatically reduced using state-of-the-art scanners, such as 320-row detector CT (320-CT), without changing coronary CTA diagnostic accuracy. To optimize and further reduce the radiation dose, new iterative reconstruction algorithms were released recently by several CT manufacturers, and now they are used routinely in coronary CTA. This paper presents our first experience using coronary CTA with 320-CT and the Adaptive Iterative Dose Reduction 3D (AIDR-3D). In addition, we describe the current indications for coronary CTA in our practice as well as the acquisition standard protocols and protocols related to CT application for radiation dose reduction. In conclusion, coronary CTA radiation dose can be dramatically reduced following the 'as low as reasonable achievable' principle by combination of exam indication and well-documented technics for radiation dose reduction, such as beta blockers, low-kV, and also the newest iterative dose reduction software as AIDR-3D. (author)

  15. Computed tomographic studies of the basis pedunculi in chronic hemiplegic patients: Topographic correlation between cerebral lesion and midbrain shrinkage

    Warabi, T.; Miyasaka, K.; Inoue, K.; Nakamura, N.

    1987-09-01

    A computed tomographic method for analyzing the shrinkage of the basis pedunculi (BP) due to the secondary degeneration of the descending fibers was applied in correlation to the site of cerebral lesions in 89 chronic hemiplegic patients. Cerebral lesions in the anterior corona radiata or the anterior limb of the capsula interna caused shrinkage of the medial BP. Lesions in the central corona radiata or the genu and posterior limb of the capsula interna caused shrinkage of the central BP, while lesions of the posterior corona radiata or the posterior limb of the capsula interna caused shrinkage of the lateral BP. These results suggested that CT images are able to reveal the principle sites of atrophy of the descending fiber tracts in chronic hemiplegia.

  16. Clinical, histologic, and computed tomographic features of oral papillary squamous cell carcinoma in dogs: 9 cases (2008- 2011).

    Soukup, Jason W; Snyder, Christopher J; Simmons, Betsie T; Pinkerton, Marie E; Chun, Ruthanne

    2013-01-01

    Medical records of dogs diagnosed with oral papillary squamous cell carcinoma between December 2008 and April 2011 were reviewed. Information abstracted included signalment, tumor location, tumor size, computed tomographic (CT) features, evidence of metastatic disease based on cytologic examination of lymph node aspirates and thoracic radiography, treatment, surgical margins, histologic features, and treatment outcome. Dogs included in the study were all sexually altered, predominantly large breed dogs with a mean age of 3.9-years (range, 0.5 to 9.0-years). The most common location was the rostral maxilla. Invasion of underlying bone and lymphadenopathy were evident on CT imaging in most dogs. No evidence of metastasis was found on mandibular lymph node cytology and thoracic radiography. Histologic analysis revealed similar morphologic findings for all surgically resected tumors. Surgical excision with 1-2 cm margins was complete in all cases, with a mean tumor-free interval of 12.1-months.

  17. Comparison of alveolar ridge preservation method using three dimensional micro-computed tomographic analysis and two dimensional histometric evaluation

    Park, Young Seok; Kim, Sung Tae; Oh, Seung Hee; Park, Hee Jung; Lee, Sophia; Kim, Taeil; Lee, Young Kyu; Heo, Min Suk [School of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    2014-06-15

    This study evaluated the efficacy of alveolar ridge preservation methods with and without primary wound closure and the relationship between histometric and micro-computed tomographic (CT) data. Porcine hydroxyapatite with polytetrafluoroethylene membrane was implanted into a canine extraction socket. The density of the total mineralized tissue, remaining hydroxyapatite, and new bone was analyzed by histometry and micro-CT. The statistical association between these methods was evaluated. Histometry and micro-CT showed that the group which underwent alveolar preservation without primary wound closure had significantly higher new bone density than the group with primary wound closure (P<0.05). However, there was no significant association between the data from histometry and micro-CT analysis. These results suggest that alveolar ridge preservation without primary wound closure enhanced new bone formation more effectively than that with primary wound closure. Further investigation is needed with respect to the comparison of histometry and micro-CT analysis.

  18. Hepatic Rupture Caused by Hemolysis, Elevated Liver Enzyme, and Low Platelet Count Syndrome: A Case Report with Computed Tomographic and Conventional Angiographic Findings

    Lee, Cheong Bok; Ahn, Jae Hong; Choi, Soo Jung; Lee, Jong Hyeog; Park, Man Soo; Jung, Seung Mun; Ryu, Dae Sik [Dept. of Radiology, Asan Foundation, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung (Korea, Republic of)

    2013-03-15

    The authors recently obtained successful clinical outcome after embolization of the hepatic artery and right inferior phrenic artery in a pregnant patient with hemolysis, elevated liver enzyme, and low platelet count (HELLP) syndrome causing hepatic rupture. We report the computed tomographic and conventional angiographic findings in a case of HELLP syndrome, resulting in hepatic infarction and rupture with active bleeding.

  19. Effects of cardiac medications for patients with obstructive coronary artery disease by coronary computed tomographic angiography: Results from the multicenter CONFIRM registry

    J. Schulman-Marcus (Joshua); B.T. Hartaigh (Bríain ó); A.E. Giambrone (Ashley E.); H. Gransar (Heidi); V. Valenti (Valentina); D.S. Berman (Daniel); M.J. Budoff (Matthew J.); S. Achenbach (Stephan); M. Al-Mallah (Mouaz); D. Andreini (Daniele); F. Cademartiri (Filippo); T.Q. Callister (Tracy); H.-J. Chang (Hyuk-Jae); K. Chinnaiyan (Kavitha); B.J.W. Chow (Benjamin); R.C. Cury (Ricardo); A. Delago (Augustin); M. Hadamitzky (Martin); J. Hausleiter (Jörg); G.M. Feuchtner (Gudrun); Y.-J. Kim (Yong-Jin); P.A. Kaufmann (Philipp A.); J. Leipsic (Jonathon); F.Y. Lin (Fay); E. Maffei (Erica); G. Pontone (Gianluca); G.L. Raff (Gilbert); L.J. Shaw (Leslee J.); T.C. Villines (Todd); A. Dunning (Allison); J.K. Min (James)

    2015-01-01

    textabstractObjective: This study sought to determine the correlation between baseline cardiac medications and cardiovascular outcomes in patients with obstructive coronary artery disease (CAD) diagnosed by coronary computed tomographic angiography (CCTA). Methods: 1637 patients (mean age 64.8±10.2

  20. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT). Part II: On 3D model accuracy

    Liang Xin, E-mail: Xin.Liang@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); College of Stomatology, Dalian Medical University (China); Lambrichts, Ivo, E-mail: Ivo.Lambrichts@uhasselt.b [Department of Basic Medical Sciences, Histology and Electron Microscopy, Faculty of Medicine, University of Hasselt, Diepenbeek (Belgium); Sun Yi, E-mail: Sunyihello@hotmail.co [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Denis, Kathleen, E-mail: kathleen.denis@groept.b [Department of Industrial Sciences and Techology-Engineering (IWT), XIOS Hogeschool Limburg, Hasselt (Belgium); Hassan, Bassam, E-mail: b.hassan@acta.n [Department of Oral Radiology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam (Netherlands); Li Limin, E-mail: Limin.Li@uz.kuleuven.b [Department of Paediatric Dentistry and Special Dental Care, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Pauwels, Ruben, E-mail: Ruben.Pauwels@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Jacobs, Reinhilde, E-mail: Reinhilde.Jacobs@uz.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium)

    2010-08-15

    Aim: The study aim was to compare the geometric accuracy of three-dimensional (3D) surface model reconstructions between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: A dry human mandible was scanned with five CBCT systems (NewTom 3G, Accuitomo 3D, i-CAT, Galileos, Scanora 3D) and one MSCT scanner (Somatom Sensation 16). A 3D surface bone model was created from the six systems. The reference (gold standard) 3D model was obtained with a high resolution laser surface scanner. The 3D models from the five systems were compared with the gold standard using a point-based rigid registration algorithm. Results: The mean deviation from the gold standard for MSCT was 0.137 mm and for CBCT were 0.282, 0.225, 0.165, 0.386 and 0.206 mm for the i-CAT, Accuitomo, NewTom, Scanora and Galileos, respectively. Conclusion: The results show that the accuracy of CBCT 3D surface model reconstructions is somewhat lower but acceptable comparing to MSCT from the gold standard.

  1. Automatic reconstruction of 3D urban landscape by computing connected regions and assigning them an average altitude from LiDAR point cloud image

    Kawata, Yoshiyuki; Koizumi, Kohei

    2014-10-01

    The demand of 3D city modeling has been increasing in many applications such as urban planing, computer gaming with realistic city environment, car navigation system with showing 3D city map, virtual city tourism inviting future visitors to a virtual city walkthrough and others. We proposed a simple method for reconstructing a 3D urban landscape from airborne LiDAR point cloud data. The automatic reconstruction method of a 3D urban landscape was implemented by the integration of all connected regions, which were extracted and extruded from the altitude mask images. These mask images were generated from the gray scale LiDAR image by the altitude threshold ranges. In this study we demonstrated successfully in the case of Kanazawa city center scene by applying the proposed method to the airborne LiDAR point cloud data.

  2. Linking microscopic spatial patterns of tissue destruction in emphysema to macroscopic decline in stiffness using a 3D computational model.

    Harikrishnan Parameswaran

    2011-04-01

    Full Text Available Pulmonary emphysema is a connective tissue disease characterized by the progressive destruction of alveolar walls leading to airspace enlargement and decreased elastic recoil of the lung. However, the relationship between microscopic tissue structure and decline in stiffness of the lung is not well understood. In this study, we developed a 3D computational model of lung tissue in which a pre-strained cuboidal block of tissue was represented by a tessellation of space filling polyhedra, with each polyhedral unit-cell representing an alveolus. Destruction of alveolar walls was mimicked by eliminating faces that separate two polyhedral either randomly or in a spatially correlated manner, in which the highest force bearing walls were removed at each step. Simulations were carried out to establish a link between the geometries that emerged and the rate of decline in bulk modulus of the tissue block. The spatially correlated process set up by the force-based destruction lead to a significantly faster rate of decline in bulk modulus accompanied by highly heterogeneous structures than the random destruction pattern. Using the Karhunen-Loève transformation, an estimator of the change in bulk modulus from the first four moments of airspace cell volumes was setup. Simulations were then obtained for tissue destruction with different idealized alveolar geometry, levels of pre-strain, linear and nonlinear elasticity assumptions for alveolar walls and also mixed destruction patterns where both random and force-based destruction occurs simultaneously. In all these cases, the change in bulk modulus from cell volumes was accurately estimated. We conclude that microscopic structural changes in emphysema and the associated decline in tissue stiffness are linked by the spatial pattern of the destruction process.

  3. Bayesian 3D X-ray computed tomography image reconstruction with a scaled Gaussian mixture prior model

    Wang, Li; Gac, Nicolas; Mohammad-Djafari, Ali [Laboratoire des Signaux et Systèmes 3, Rue Joliot-Curie 91192 Gif sur Yvette (France)

    2015-01-13

    In order to improve quality of 3D X-ray tomography reconstruction for Non Destructive Testing (NDT), we investigate in this paper hierarchical Bayesian methods. In NDT, useful prior information on the volume like the limited number of materials or the presence of homogeneous area can be included in the iterative reconstruction algorithms. In hierarchical Bayesian methods, not only the volume is estimated thanks to the prior model of the volume but also the hyper parameters of this prior. This additional complexity in the reconstruction methods when applied to large volumes (from 512{sup 3} to 8192{sup 3} voxels) results in an increasing computational cost. To reduce it, the hierarchical Bayesian methods investigated in this paper lead to an algorithm acceleration by Variational Bayesian Approximation (VBA) [1] and hardware acceleration thanks to projection and back-projection operators paralleled on many core processors like GPU [2]. In this paper, we will consider a Student-t prior on the gradient of the image implemented in a hierarchical way [3, 4, 1]. Operators H (forward or projection) and H{sup t} (adjoint or back-projection) implanted in multi-GPU [2] have been used in this study. Different methods will be evalued on synthetic volume 'Shepp and Logan' in terms of quality and time of reconstruction. We used several simple regularizations of order 1 and order 2. Other prior models also exists [5]. Sometimes for a discrete image, we can do the segmentation and reconstruction at the same time, then the reconstruction can be done with less projections.

  4. Efficient 3D nonlinear warping of computed tomography: two high-performance implementations using OpenGL

    Levin, David; Dey, Damini; Slomka, Piotr

    2005-04-01

    We have implemented two hardware accelerated Thin Plate Spline (TPS) warping algorithms. The first algorithm is a hardware-software approach (HW-TPS) that uses OpenGL Vertex Shaders to perform a grid warp. The second is a Graphics Processor based approach (GPU-TPS) that uses the OpenGL Shading Language to perform all warping calculations on the GPU. Comparison with a software TPS algorithm was used to gauge the speed and quality of both hardware algorithms. Quality was analyzed visually and using the Sum of Absolute Difference (SAD) similarity metric. Warping was performed using 92 user-defined displacement vectors for 512x512x173 serial lung CT studies, matching normal-breathing and deep-inspiration scans. On a Xeon 2.2 Ghz machine with an ATI Radeon 9800XT GPU the GPU-TPS required 26.1 seconds to perform a per-voxel warp compared to 148.2 seconds for the software algorithm. The HW-TPS needed 1.63 seconds to warp the same study while the GPU-TPS required 1.94 seconds and the software grid transform required 22.8 seconds. The SAD values calculated between the outputs of each algorithm and the target CT volume were 15.2%, 15.4% and 15.5% for the HW-TPS, GPU-TPS and both software algorithms respectively. The computing power of ubiquitous 3D graphics cards can be exploited in medical image processing to provide order of magnitude acceleration of nonlinear warping algorithms without sacrificing output quality.

  5. Advanced 3D textile composites reinforcements meso F.E analyses based on X-ray computed tomography

    Naouar, Naim; Vidal-Salle, Emmanuelle; Boisse, Philippe

    2016-10-01

    Meso-FE modelling of 3D textile composites is a powerful tool, which can help determine mechanical properties and permeability of the reinforcements or composites. The quality of the meso FE analyses depends on the quality of the initial model. A direct method based on X-ray tomography imaging is introduced to determine finite element models based on the real geometry of 3D composite reinforcements. The method is particularly suitable regarding 3D textile reinforcements for which internal geometries are numerous and complex. The approach used for the separation of the yarns in different directions is specialized because the fibres flow in three-dimensional space. An analysis of the image's texture is performed. A hyperelastic model developed for fibre bundles is used for the simulation of the deformation of the 3D reinforcement.

  6. Lagrangian Finite Element Method for 3D time-dependent viscoelastic flow computation using integral constitutive models

    Rasmussen, Henrik Koblitz

    2000-01-01

    Lagrangian Integral Method) is a finite element method where Galerkons method is used for solving the governing equation in rectangular coordinates numerically. In the present implementation the velocity and pressure fields are approximated with tri-linear and constant shape functions, respectivly.The 3D LIM......) and polymeric solutions. Secondly, the 3D-LIM has also been applied to calculate the inflation of a thick sheet of a polymeric melt into a elliptic cylinder. These problems all include free surfaces. As the governing equations are solved for the particle positions, the motion of surfaces can be followed easily......A new technique for the numerical 3D simulation of time dependent flow of viscoelastic fluid is presented. The technique is based on a Lagrangian kinematics description of the fluid flow. The fluid is described by the Rivlin Sawyer integral constitutive equation. The method (referred to as the 3D...

  7. Computer-aided multiple-head 3D printing system for printing of heterogeneous organ/tissue constructs

    Jin Woo Jung; Jung-Seob Lee; Dong-Woo Cho

    2016-01-01

    Recently, much attention has focused on replacement or/and enhancement of biological tissues via the use of cell-laden hydrogel scaffolds with an architecture that mimics the tissue matrix, and with the desired three-dimensional (3D) external geometry. However, mimicking the heterogeneous tissues that most organs and tissues are formed of is challenging. Although multiple-head 3D printing systems have been proposed for fabricating heterogeneous cell-laden hydrogel scaffolds, to date only the ...

  8. Data Extraction from Computer Acquired Images of a Given 3D Environment for Enhanced Computer Vision and its Applications in Kinematic Design of Robos

    K. Selvaraj

    2010-01-01

    Full Text Available Problem statement: Literature review was mainly aiming at recognition of objects by the computer and to make explicit the information that is implicit in the attributes of 3D objects and their relative positioning in the 3D Environment (3DE as seen in the 2D images. However quantitative estimate of position of objects in the 3DE in terms of their x, y and z co-ordinates was not touched upon. This issue assumes important dimension in areas like Kinematic Design of Robos (KDR, while the Robo is negotiating with z field or Depth Field (DF. Approach: The existing methods such as pattern matching used by Robos for Depth Visualization (DV using a set of external commands, were reviewed in detail. A methodology was developed in this study to enable the Robo to quantify the depth by itself, instead of looking for external commands. Results: The Results are presented and discussed. The Results are presented and discussed. The major conclusions drawn based on the results were listed. Conclusion: The major contribution of the present study consists of computing the Depth (D1 corresponding to the depth (d measured from the photographic image of a 3DE. It had been concluded that, there exists an excellent agreement between the computed depth D1 and the corresponding actual Depth (D. The percent deviation of D1 from D (DP lies between ±2 over the entire region of the (DF. Through suitable interfacing of the developed equation with the kinematic design of Robos, the Robo can generate its own commands for DF negotiations.

  9. Audio-visual perception of 3D cinematography: an fMRI study using condition-based and computation-based analyses.

    Ogawa, Akitoshi; Bordier, Cecile; Macaluso, Emiliano

    2013-01-01

    The use of naturalistic stimuli to probe sensory functions in the human brain is gaining increasing interest. Previous imaging studies examined brain activity associated with the processing of cinematographic material using both standard "condition-based" designs, as well as "computational" methods based on the extraction of time-varying features of the stimuli (e.g. motion). Here, we exploited both approaches to investigate the neural correlates of complex visual and auditory spatial signals in cinematography. In the first experiment, the participants watched a piece of a commercial movie presented in four blocked conditions: 3D vision with surround sounds (3D-Surround), 3D with monaural sound (3D-Mono), 2D-Surround, and 2D-Mono. In the second experiment, they watched two different segments of the movie both presented continuously in 3D-Surround. The blocked presentation served for standard condition-based analyses, while all datasets were submitted to computation-based analyses. The latter assessed where activity co-varied with visual disparity signals and the complexity of auditory multi-sources signals. The blocked analyses associated 3D viewing with the activation of the dorsal and lateral occipital cortex and superior parietal lobule, while the surround sounds activated the superior and middle temporal gyri (S/MTG). The computation-based analyses revealed the effects of absolute disparity in dorsal occipital and posterior parietal cortices and of disparity gradients in the posterior middle temporal gyrus plus the inferior frontal gyrus. The complexity of the surround sounds was associated with activity in specific sub-regions of S/MTG, even after accounting for changes of sound intensity. These results demonstrate that the processing of naturalistic audio-visual signals entails an extensive set of visual and auditory areas, and that computation-based analyses can track the contribution of complex spatial aspects characterizing such life-like stimuli.

  10. Audio-visual perception of 3D cinematography: an fMRI study using condition-based and computation-based analyses.

    Akitoshi Ogawa

    Full Text Available The use of naturalistic stimuli to probe sensory functions in the human brain is gaining increasing interest. Previous imaging studies examined brain activity associated with the processing of cinematographic material using both standard "condition-based" designs, as well as "computational" methods based on the extraction of time-varying features of the stimuli (e.g. motion. Here, we exploited both approaches to investigate the neural correlates of complex visual and auditory spatial signals in cinematography. In the first experiment, the participants watched a piece of a commercial movie presented in four blocked conditions: 3D vision with surround sounds (3D-Surround, 3D with monaural sound (3D-Mono, 2D-Surround, and 2D-Mono. In the second experiment, they watched two different segments of the movie both presented continuously in 3D-Surround. The blocked presentation served for standard condition-based analyses, while all datasets were submitted to computation-based analyses. The latter assessed where activity co-varied with visual disparity signals and the complexity of auditory multi-sources signals. The blocked analyses associated 3D viewing with the activation of the dorsal and lateral occipital cortex and superior parietal lobule, while the surround sounds activated the superior and middle temporal gyri (S/MTG. The computation-based analyses revealed the effects of absolute disparity in dorsal occipital and posterior parietal cortices and of disparity gradients in the posterior middle temporal gyrus plus the inferior frontal gyrus. The complexity of the surround sounds was associated with activity in specific sub-regions of S/MTG, even after accounting for changes of sound intensity. These results demonstrate that the processing of naturalistic audio-visual signals entails an extensive set of visual and auditory areas, and that computation-based analyses can track the contribution of complex spatial aspects characterizing such life

  11. A Computational Investigation of the Finite-Time Blow-Up of the 3D Incompressible Euler Equations Based on the Voigt Regularization

    Larios, Adam; Titi, Edriss S; Wingate, Beth

    2015-01-01

    We report the results of a computational investigation of two recently proved blow-up criteria for the 3D incompressible Euler equations. These criteria are based on an inviscid regularization of the Euler equations known as the 3D Euler-Voigt equations. The latter are known to be globally well-posed. Moreover, simulations of the 3D Euler-Voigt equations also require less resolution than simulations of the 3D Euler equations for fixed values of the regularization parameter $\\alpha>0$. Therefore, the new blow-up criteria allow one to gain information about possible singularity formation in the 3D Euler equations indirectly; namely, by simulating the better-behaved 3D Euler-Voigt equations. The new criteria are only known to be sufficient criteria for blow-up. Therefore, to test the robustness of the inviscid-regularization approach, we also investigate analogous criteria for blow-up of the 1D Burgers equation, where blow-up is well-known to occur.

  12. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT). Part II: On 3D model accuracy

    Liang, X.; Lambrichts, I.; Sun, Y.; Denis, K.; Hassan, B.; Li, L.; Pauwels, R.; Jacobs, R.

    2010-01-01

    Aim: The study aim was to compare the geometric accuracy of three-dimensional (3D) surface model reconstructions between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: A dry human mandible was scanned with five CBCT systems (NewTom 3G,

  13. Stereological measures of trabecular bone structure: comparison of 3D micro computed tomography with 2D histological sections in human proximal tibial bone biopsies

    Thomsen, Jesper Skovhus; Laib, A.; Koller, B.;

    2005-01-01

    tibial metaphysis. The biopsies were embedded in methylmetacrylate before microCT scanning in a Scanco microCT 40 scanner at a resolution of 20 x 20 x 20 microm3, and the 3D data sets were analysed with a computer program. After microCT scanning, 16 sections were cut from the central 2 mm of each biopsy...

  14. Contributions of the musculus uvulae to velopharyngeal closure quantified with a 3D multi-muscle computational model

    Inouye, Joshua M.; Lin, Kant Y.; Perry, Jamie L.; Blemker, Silvia S.

    2016-01-01

    The convexity of the dorsal surface of the velum is critical for normal velopharyngeal (VP) function and is largely attributed to the levator veli palatini (LVP) and musculus uvulae (MU). Studies have correlated a concave or flat nasal velar surface to symptoms of VP dysfunction including hypernasality and nasal air emission. In the context of surgical repair of cleft palates, the MU has been given relatively little attention in the literature compared with the larger LVP. A greater understanding of the mechanics of the MU will provide insight into understanding the influence of a dysmorphic MU, as seen in cleft palate, as it relates to VP function. The purpose of this study was to quantify the contributions of the MU to VP closure in a computational model. We created a novel 3D finite element model of the VP mechanism from MRI data collected from an individual with healthy non-cleft VP anatomy. The model components included the velum, posterior pharyngeal wall (PPW), LVP, and MU. Simulations were based on the muscle and soft tissue mechanical properties from the literature. We found that, similar to previous hypotheses, the MU acts as i) a space-occupying structure and ii) a velar extensor. As a space-occupying structure, the MU helps to nearly triple the midline VP contact length. As a velar extensor, the MU acting alone without the LVP decreases the VP distance 62%. Furthermore, activation of the MU decreases the LVP activation required for closure almost three-fold, from 20% (without MU) to 8% (with MU). Our study suggests that any possible salvaging and anatomical reconstruction of viable MU tissue in a cleft patient may improve VP closure due to its mechanical function. In the absence or dysfunction of MU tissue, implantation of autologous or engineered tissues at the velar midline, as a possible substitute for the MU, may produce a geometric convexity more favorable to VP closure. In the future, more complex models will provide further insight into optimal

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

    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.

  16. The occlusion-adjusted prefabricated 3D mirror image templates by computer simulation: the image-guided navigation system application in difficult cases of head and neck reconstruction.

    Cheng, Hsu-Tang; Wu, Chao-I; Tseng, Ching-Shiow; Chen, Hung-Chi; Lee, Wu-Song; Chen, Philip Kuo-Ting; Chang, Sophia Chia-Ning

    2009-11-01

    Computer applications in head and neck reconstruction are rapidly emerging and create not only a virtual environment for presurgical planning, but also help in image-guided navigational surgery. This study evaluates the use of prefabricated 3-dimensional (3D) mirror image templates made by computer-simulated adjusted occlusions to assist in microvascular prefabricated flap insertion during reconstructive surgery. Five patients underwent tumor ablation surgery in 1999 and survived for 8 years. Four of the patients with malignancy received radiation therapy. All patients in this study suffered from severe malocclusion causing trismus, headache, temporomandibular joint pain, an unsymmetrical face, and the inability of further osseointegrated teeth insertion. They underwent a 3D computer tomography examination and the nonprocessed raw data were sent for computer simulation in adjusting occlusion; thus, a mirror image template could be fabricated for microsurgical flap guidance. The computer simulated occlusion was acceptable and facial symmetry obtained. The use of the template resulted in a shorter operation time and recovery was as expected. The computer-simulated occlusion-adjusted 3D mirror image templates aid in the use of free vascularized bone flaps for restoring continuity to the mandible. The coordinated arch will help with further osseointegration teeth insertion.

  17. Hybrid 3-D rocket trajectory program. Part 1: Formulation and analysis. Part 2: Computer programming and user's instruction. [computerized simulation using three dimensional motion analysis

    Huang, L. C. P.; Cook, R. A.

    1973-01-01

    Models utilizing various sub-sets of the six degrees of freedom are used in trajectory simulation. A 3-D model with only linear degrees of freedom is especially attractive, since the coefficients for the angular degrees of freedom are the most difficult to determine and the angular equations are the most time consuming for the computer to evaluate. A computer program is developed that uses three separate subsections to predict trajectories. A launch rail subsection is used until the rocket has left its launcher. The program then switches to a special 3-D section which computes motions in two linear and one angular degrees of freedom. When the rocket trims out, the program switches to the standard, three linear degrees of freedom model.

  18. Development of a stereolithography (STL input and computer numerical control (CNC output algorithm for an entry-level 3-D printer

    Brown, Andrew

    2014-08-01

    Full Text Available This paper presents a prototype Stereolithography (STL file format slicing and tool-path generation algorithm, which serves as a data front-end for a Rapid Prototyping (RP entry- level three-dimensional (3-D printer. Used mainly in Additive Manufacturing (AM, 3-D printers are devices that apply plastic, ceramic, and metal, layer by layer, in all three dimensions on a flat surface (X, Y, and Z axis. 3-D printers, unfortunately, cannot print an object without a special algorithm that is required to create the Computer Numerical Control (CNC instructions for printing. An STL algorithm therefore forms a critical component for Layered Manufacturing (LM, also referred to as RP. The purpose of this study was to develop an algorithm that is capable of processing and slicing an STL file or multiple files, resulting in a tool-path, and finally compiling a CNC file for an entry-level 3- D printer. The prototype algorithm was implemented for an entry-level 3-D printer that utilises the Fused Deposition Modelling (FDM process or Solid Freeform Fabrication (SFF process; an AM technology. Following an experimental method, the full data flow path for the prototype algorithm was developed, starting with STL data files, and then processing the STL data file into a G-code file format by slicing the model and creating a tool-path. This layering method is used by most 3-D printers to turn a 2-D object into a 3-D object. The STL algorithm developed in this study presents innovative opportunities for LM, since it allows engineers and architects to transform their ideas easily into a solid model in a fast, simple, and cheap way. This is accomplished by allowing STL models to be sliced rapidly, effectively, and without error, and finally to be processed and prepared into a G-code print file.

  19. A Mechanical Study of a Glass Fabric-Thermoplastic Resin Composite: 3D-DIC and X-ray tomographic observations explained by numerical simulations based on a spectral solver

    Boufaida, Zakariya; André, Stéphane; Farge, Laurent

    2016-01-01

    In the study presented in this paper, we analyzed the mechanical response of a glass fiber plain weave/polymer composite at the fabric millimetric mesoscale. The detail of the stress and strain fields in a fabric repeating unit cell was numerically calculated using CraFT (Composite response and Fourier Transforms), a code specifically conceived for simulating the mechanical behaviour of materials with complex microstructure. The local strain fields obtained by simulation were found to be in very good agreement with measurements carried out using 3D Digital Image Correlation (3D DIC). From numerical stress fields calculated with the CraFT solver, we also highlighted the subregions inside the periodic mesostructure where there is maximum stress. Furthermore, with X-ray tomography post mortem measurements, we were able to confirm that certain damage modes were well initiated in these microstructure subregions of stress concentration.

  20. 3D surface reconstruction for facial model from tomographic images based on multi-view visibility detection%基于多视点可见性检测的面皮三维表面重建

    贺毅岳; 耿国华; 茹少峰; 贾甲; 贺小伟

    2013-01-01

    提出了一种面皮三维表面重建方法SRMFM(surface reconstruction method for facial model),首先采用MC算法重建面皮三维模型,在Frankfurt坐标校正基础上建立面皮体素模型,然后采用基于广度优先遍历的多视点可见性检测算法提取表面顶点,创建面皮三维表面模型.可从断层图像自动、快速地重建出保持表面细节特征的面皮三维表面模型.%A 3D SRMFM (surface reconstruction method for facial model) is proposed,which employs Marching Cubes algorithm to construct 3D facial model,and builds facial voxel model after Frankfurt coordinate correction is accomplished,then applies MVD (multi-view visibility detection) based on BFS (breadth first search) to extract external surface vertexes from which facial surface model is constructed finally.Achieved the goal of reconstructing facial surface model automatically and quickly with geometric details well kept.SRMFM is an automatic and efficient 3D facial surface reconstruction method capable of keeping geometric details excellently.

  1. 3-D computational model of poly (lactic acid)/halloysite nanocomposites: Predicting elastic properties and stress analysis

    De Silva, R. T.; Pasbakhsh, Pooria; Goh, K. L.

    2014-01-01

    of nanotubes with fixed aspect ratio and the proposed alternative real-structure based model takes the experimentally observed variations of HNTs sizes, impurities and aspect ratios into account. The requirements of the 3-D HNTs nanocomposite models have been explored by testing idealized, real structure based...... and aspect ratios. Numerical studies were validated with experimental investigations and the developed real-structure based model gave more accurate results than idealized and analytical models. (C) 2014 Elsevier Ltd. All rights reserved....

  2. Cardiac C-arm computed tomography using a 3D + time ROI reconstruction method with spatial and temporal regularization

    Mory, Cyril, E-mail: cyril.mory@philips.com [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, F-69621 Villeurbanne Cedex (France); Philips Research Medisys, 33 rue de Verdun, 92156 Suresnes (France); Auvray, Vincent; Zhang, Bo [Philips Research Medisys, 33 rue de Verdun, 92156 Suresnes (France); Grass, Michael; Schäfer, Dirk [Philips Research, Röntgenstrasse 24–26, D-22335 Hamburg (Germany); Chen, S. James; Carroll, John D. [Department of Medicine, Division of Cardiology, University of Colorado Denver, 12605 East 16th Avenue, Aurora, Colorado 80045 (United States); Rit, Simon [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1 (France); Centre Léon Bérard, 28 rue Laënnec, F-69373 Lyon (France); Peyrin, Françoise [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, F-69621 Villeurbanne Cedex (France); X-ray Imaging Group, European Synchrotron, Radiation Facility, BP 220, F-38043 Grenoble Cedex (France); Douek, Philippe; Boussel, Loïc [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1 (France); Hospices Civils de Lyon, 28 Avenue du Doyen Jean Lépine, 69500 Bron (France)

    2014-02-15

    Purpose: Reconstruction of the beating heart in 3D + time in the catheter laboratory using only the available C-arm system would improve diagnosis, guidance, device sizing, and outcome control for intracardiac interventions, e.g., electrophysiology, valvular disease treatment, structural or congenital heart disease. To obtain such a reconstruction, the patient's electrocardiogram (ECG) must be recorded during the acquisition and used in the reconstruction. In this paper, the authors present a 4D reconstruction method aiming to reconstruct the heart from a single sweep 10 s acquisition. Methods: The authors introduce the 4D RecOnstructiOn using Spatial and TEmporal Regularization (short 4D ROOSTER) method, which reconstructs all cardiac phases at once, as a 3D + time volume. The algorithm alternates between a reconstruction step based on conjugate gradient and four regularization steps: enforcing positivity, averaging along time outside a motion mask that contains the heart and vessels, 3D spatial total variation minimization, and 1D temporal total variation minimization. Results: 4D ROOSTER recovers the different temporal representations of a moving Shepp and Logan phantom, and outperforms both ECG-gated simultaneous algebraic reconstruction technique and prior image constrained compressed sensing on a clinical case. It generates 3D + time reconstructions with sharp edges which can be used, for example, to estimate the patient's left ventricular ejection fraction. Conclusions: 4D ROOSTER can be applied for human cardiac C-arm CT, and potentially in other dynamic tomography areas. It can easily be adapted to other problems as regularization is decoupled from projection and back projection.

  3. 3D non-destructive fluorescent X-ray computed tomography (FXCT) with a CdTe array

    Yoon, Chang Yeon; Lee, Won Ho; Kim, Young Hak [Dept. of Bio-convergence Engineering, Korea University Graduate School, Seoul (Korea, Republic of)

    2015-10-15

    In our research, the material was exposed to an X-ray and not only the conventional transmission image but also 3D images based on the information of characteristic X-ray detected by a 2D CdTe planar detector array were reconstructed. Since atoms have their own characteristic X-ray energy, our system was able to discriminate materials of even a same density if the materials were composed of different atomic numbers. We applied FXCT to distinguish various unknown materials with similar densities. The materials with similar densities were clearly distinguished in the 3D reconstructed images based on the information of the detected characteristic X-ray, while they were not discriminated from each other in the images based on the information of the detected transmission X-ray. In the fused images consisting of 3D transmitted and characteristic X-ray images, all of the positions, densities and atomic numbers of materials enclosed in plastic phantom or pipe were clearly identified by analyzing energy, position and amount of detected radiation.

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

    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

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

    Ye Chu

    2016-01-01

    Full Text Available 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.

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

    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.

  7. Analysis of factors influencing the integrated bolus peak timing in contrast-enhanced brain computed tomographic angiography

    Son, Soon Yong [Wonkwang Health Science University, Iksan (Korea, Republic of); Choi, Kwan Woo [Asan Medical Center, Seoul (Korea, Republic of); Jeong, Hoi Woun [Baekseok Culture University College, Cheonan (Korea, Republic of); Jang, Seo Goo [Soonchunhyang University, Asan (Korea, Republic of); Jung, Jae Young [Sanggye Paik Hospital, Seoul (Korea, Republic of); Yun, Jung Soo [Samsung Medical Center, Seoul (Korea, Republic of); Kim, Ki Won [Kyung Hee University Hospital at Gang-dong, Seoul (Korea, Republic of); Lee, Young Ah; Son, Jin Hyun; Min, Jung Whan [Shingu University College, Sungnam (Korea, Republic of)

    2016-03-15

    The objective of this study was to analyze the factors influencing integrated bolus peak timing in contrast- enhanced computed tomographic angiography (CTA) and to determine a method of calculating personal peak time. The optimal time was calculated by performing multiple linear regression analysis, after finding the influence factors through correlation analysis between integrated peak time of contrast medium and personal measured value by monitoring CTA scans. The radiation exposure dose in CTA was 716.53 mGy·cm and the radiation exposure dose in monitoring scan was 15.52 mGy (2 - 34 mGy). The results were statistically significant (p < .01). Regression analysis revealed, a -0.160 times decrease with a one-step increase in heart rate in male, and -0.004, -0.174, and 0.006 times decrease with one-step in DBP, heart rate, and blood sugar, respectively, in female. In a consistency test of peak time by calculating measured peak time and peak time by using the regression equation, the consistency was determined to be very high for male and female. This study could prevent unnecessary dose exposure by encouraging in clinic calculation of personal integrated peak time of contrast medium prior to examination.

  8. 256-Slice coronary computed tomographic angiography in patients with atrial fibrillation: optimal reconstruction phase and image quality

    Oda, Seitaro; Yuki, Hideaki; Kidoh, Masafumi; Utsunomiya, Daisuke; Nakaura, Takeshi; Namimoto, Tomohiro; Yamashita, Yasuyuki [Kumamoto University, Department of Diagnostic Radiology, Faculty of Life Sciences, Chuou-ku, Kumamoto (Japan); Honda, Keiichi; Yoshimura, Akira; Katahira, Kazuhiro [Kumamoto Chuo Hospital, Department of Diagnostic Radiology, Minami-ku, Kumamoto (Japan); Noda, Katsuo; Oshima, Shuichi [Kumamoto Chuo Hospital, Department of Cardiology, Minami-ku, Kumamoto (Japan)

    2016-01-15

    To assess the optimal reconstruction phase and the image quality of coronary computed tomographic angiography (CCTA) in patients with atrial fibrillation (AF). We performed CCTA in 60 patients with AF and 60 controls with sinus rhythm. The images were reconstructed in multiple phases in all parts of the cardiac cycle, and the optimal reconstruction phase with the fewest motion artefacts was identified. The coronary artery segments were visually evaluated to investigate their assessability. In 46 (76.7 %) patients, the optimal reconstruction phase was end-diastole, whereas in 6 (10.0 %) patients it was end-systole or mid-diastole, and in 2 (3.3 %) patients it was another cardiac phase. In 53 (88.3 %) of the controls, the optimal reconstruction phase was mid-diastole, whereas it was end-systole in 4 (6.7 %), and in 3 (5.0 %) it was another cardiac phase. There was a significant difference between patients with AF and the controls in the optimal phase (p < 0.01) but not in the visual image quality score (p = 0.06). The optimal reconstruction phase in most patients with AF was the end-diastolic phase. The end-systolic phase tended to be optimal in AF patients with higher average heart rates. (orig.)

  9. Early onset cerebellar ataxia with retained tendon reflexes (EOCA and olivopontocerebellar atrophy (OPCA : a computed tomographic study.

    Pal P

    1999-10-01

    Full Text Available Computed tomographic (CT studies in olivopontocerebellar atrophies (OPCA and ′early onset cerebellar ataxia with retained tendon reflexes (EOCA′ are few and vary widely in methodology and criteria for cerebellar and brainstem atrophy. In this prospective study, CT scan observations on 26 patients (EOCA-11, OPCA-15 were compared with 31 controls using qualitative and quantitative assessment of cisterns, ventricles and atrophy of brain. Vermian and/or cerebellar hemispheric (predominantly anterior atrophy was present in 80.8% and both were equally common. Cerebral cortical atrophy (26.9% and leukoariosis (15.4% were less frequently seen. Statistically significant atrophy of pons, brachium pontis, cerebellum and midbrain was noted in patient group. No significant differences were observed between EOCA and OPCA groups. Evidence of atrophy did not correlate with either the duration of illness or the severity of cerebellar ataxia in both the groups. The severity of brainstem atrophy in 14 patients with and 12 patients without abnormal brainstem auditory evoked response did not differ significantly. This study highlights the methodology of CT evaluation for brainstem and cerebellar atrophy, draws attention to cerebral atrophy and emphasizes the lack of significant differences in CT morphology between OPCA and EOCA patients.

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

    Kim, Jae Hun; Jeong, Ho Gul; Hwang, Jae Joon; Lee, Jung Hee; Han, Sang Sun [Dept. of Oral and Maxillofacial Radiology, Yonsei University, College of Dentistry, Seoul (Korea, Republic of)

    2016-06-15

    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. 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. 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. 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.

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

    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.

  12. Fully 3D GPU PET reconstruction

    Herraiz, J.L., E-mail: joaquin@nuclear.fis.ucm.es [Grupo de Fisica Nuclear, Departmento Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Espana, S. [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Cal-Gonzalez, J. [Grupo de Fisica Nuclear, Departmento Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Vaquero, J.J. [Departmento de Bioingenieria e Ingenieria Espacial, Universidad Carlos III, Madrid (Spain); Desco, M. [Departmento de Bioingenieria e Ingenieria Espacial, Universidad Carlos III, Madrid (Spain); Unidad de Medicina y Cirugia Experimental, Hospital General Universitario Gregorio Maranon, Madrid (Spain); Udias, J.M. [Grupo de Fisica Nuclear, Departmento Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain)

    2011-08-21

    Fully 3D iterative tomographic image reconstruction is computationally very demanding. Graphics Processing Unit (GPU) has been proposed for many years as potential accelerators in complex scientific problems, but it has not been used until the recent advances in the programmability of GPUs that the best available reconstruction codes have started to be implemented to be run on GPUs. This work presents a GPU-based fully 3D PET iterative reconstruction software. This new code may reconstruct sinogram data from several commercially available PET scanners. The most important and time-consuming parts of the code, the forward and backward projection operations, are based on an accurate model of the scanner obtained with the Monte Carlo code PeneloPET and they have been massively parallelized on the GPU. For the PET scanners considered, the GPU-based code is more than 70 times faster than a similar code running on a single core of a fast CPU, obtaining in both cases the same images. The code has been designed to be easily adapted to reconstruct sinograms from any other PET scanner, including scanner prototypes.

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

    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.

  14. Computer tomographic investigation of subcutaneous adipose tissue as an indicator of body composition

    McEvoy, Fintan; Madsen, Mads T.; Nielsen, Mai B.;

    2009-01-01

    Background Modern computer tomography (CT) equipment can be used to acquire whole-body data from large animals such as pigs in minutes or less. In some circumstances, computer assisted analysis of the resulting image data can identify and measure anatomical features. The thickness of subcutaneous...... and expressed as a proportion of total volume (fat-index). A computer algorithm was used to determined 10,201 subcutaneous adipose thickness measurements in each pig for each scan. From these data, sites were selected where correlation with fat-index was optimal. Results Image analysis correctly identified...... intercostal spaces cranially. Conclusion The approach to image analysis reported permits the creation of various maps showing adipose thickness or correlation of thickness with other variables by location on the surface of the pig. The method identified novel adipose thickness measurement positions...

  15. Uniaxial Compression of Cellular Materials at a 10-1 s-1 Strain Rate Simultaneously with Synchrotron X-ray Computed Tomographic Imaging

    Patterson, Brian M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-01

    The topic is presented as a series of slides. Motivation for the work included the following: X-ray tomography is a fantastic technique for characterizing a material’s starting structure as well as for non-destructive, in situ experiments to investigate material response; 3D X-ray tomography is needed to fully characterize the morphology of cellular materials; and synchrotron micro-CT can capture 3D images without pausing experiment. Among the conclusions reached are these: High-rate radiographic and tomographic imaging (0.25 s 3D frame rate) using synchrotron CT can capture full 3D images of hyper-elastic materials at a 10-2 strain rate; dynamic true in situ uniaxial loading can be accurately captured; the three stages of compression can be imaged: bending, buckling, and breaking; implementation of linear modeling is completed; meshes have been imported into LANL modeling codes--testing and validation is underway and direct comparison and validation between in situ data and modeled mechanical response is possible.

  16. Computer tomographic and sonographic demonstration of renal haematomas following percutaneous renal biopsy

    Nebel, G.; Lingg, G.; Berg, E.; Fischer, R.

    1982-04-01

    The incidence of post-puncture haematomas following percutaneous renal biopsy in 23 patients (24 punctures) is reported. The incidence of renal haematomas was 29.1%. The diagnostic value of computer tomography and sonography is discussed. Amongst small haematomas (less than 7 ml. blood), which could only be demonstrated by computer tomography, 8.2% were purely intrarenal, 8.2% were sub-capsular and 12.3% showed combined intrarenal, subcapsular and perirenal bleeding. The incidence of sub-capsular and perirenal haematomas of 20.5% is considerably lower than has previously been reported in literature.

  17. Middle east respiratory syndrome-corona virus infection: A case report of sieral computed tomographic findings in a young male patient

    Choi, Won Jin; Lee, Ki Nam; Kang, Eun Ju; Lee, Hyuck [Dong A University Hospital, Busan (Korea, Republic of)

    2016-02-15

    Radiologic findings of Middle East respiratory syndrome (MERS), a novel coronavirus infection, have been rarely reported. We report a 30-year-old male presented with fever, abdominal pain, and diarrhea, who was diagnosed with MERS. A chest computed tomographic scan revealed rapidly developed multifocal nodular consolidations with ground-glass opacity halo and mixed consolidation, mainly in the dependent and peripheral areas. After treatment, follow-up imaging showed that these abnormalities markedly decreased but fibrotic changes developed.

  18. Comparison of usefulness of exercise testing versus coronary computed tomographic angiography for evaluation of patients suspected of having coronary artery disease

    Ovrehus, Kristian A; Jensen, Jesper K; Mickley, Hans;

    2010-01-01

    In patients suspected of having coronary artery disease (CAD), we compared the diagnostic sensitivity and specificity of exercise testing using ST-segment changes alone and ST-segment changes, angina pectoris, and hemodynamic variables compared to coronary computed tomographic angiography (CTA...... performance of CTA for the detection and exclusion of significant CAD might favor CTA as the first-line diagnostic test in patients suspected of having CAD....

  19. 3D Surface Realignment Tracking for Medical Imaging: A Phantom Study with PET Motion Correction

    Olesen, Oline Vinter; Paulsen, Rasmus Reinhold; Jensen, Rasmus Ramsbøl

    2011-01-01

    We present a complete system for motion correction in high resolution brain positron emission tomography (PET) imaging. It is based on a compact structured light scanner mounted above the patient tunnel of the Siemens High Resolution Research Tomograph PET brain scanner. The structured light system...... is equipped with a near infrared diode and uses phase-shift interferometry to compute 3D representations of the forehead of the patient. These 3D point clouds are progressively aligned to a reference surface and thereby giving the head pose changes. The estimated pose changes are used to reposition a sequence...

  20. Computed tomographic angiography or conventional coronary angiography in therapeutic decision-making

    Piers, Lieuwe H.; Dikkers, Riksta; Willems, Tineke P.; de Smet, Bart J. G. L.; Oudkerk, Matthijs; Zijlstra, Felix; Tio, Rene A.

    2008-01-01

    To evaluate non-invasive angiography using dual-source computed tomography (CT) for the determination of the most appropriate therapeutic strategy in patients with suspected coronary artery disease (CAD). CT angiography (Dual Source CT, Somatom Definition, Siemens Medical Systems, Forchheim, Germany

  1. Computed tomographic study of the skeletal musculature of the lower body in 45 postpolio patients

    Ivanyi, B; Redekop, W; de Jongh, R; de Visser, Marianne

    1998-01-01

    Muscle computed tomography (CT) and muscle strength assessment of the pelvic girdle and leg muscles were performed in 32 postpolio patients experiencing new muscle weakness, and in 13 postpolio patients with stable neuromuscular condition. Muscles of the postpolio patients experiencing new muscle we

  2. Computed tomographic characteristics of interval and post screen carcinomas in lung cancer screening

    Scholten, E.T.; Horeweg, N.; Koning, H.J. de; Vliegenthart, R.; Oudkerk, M.; Mali, W.P.; Jong, P.A. de

    2015-01-01

    OBJECTIVES: To analyse computed tomography (CT) findings of interval and post-screen carcinomas in lung cancer screening. METHODS: Consecutive interval and post-screen carcinomas from the Dutch-Belgium lung cancer screening trial were included. The prior screening and the diagnostic chest CT were re

  3. Computer-assisted 3D design software for teaching neuro-ophthalmology of the oculomotor system and training new retinal surgery techniques

    Glittenberg, Carl; Binder, Susanne

    2004-07-01

    Purpose: To create a more effective method of demonstrating complex subject matter in ophthalmology with the use of high end, 3-D, computer aided animation and interactive multimedia technologies. Specifically, to explore the possibilities of demonstrating the complex nature of the neuroophthalmological basics of the human oculomotor system in a clear and non confusing way, and to demonstrate new forms of retinal surgery in a manner that makes the procedures easier to understand for other retinal surgeons. Methods and Materials: Using Reflektions 4.3, Monzoom Pro 4.5, Cinema 4D XL 5.03, Cinema 4D XL 8 Studio Bundle, Mediator 4.0, Mediator Pro 5.03, Fujitsu-Siemens Pentium III and IV, Gericom Webgine laptop, M.G.I. Video Wave 1.0 and 5, Micrografix Picture Publisher 6.0 and 8, Amorphium 1.0, and Blobs for Windows, we created 3-D animations showing the origin, insertion, course, main direction of pull, and auxiliary direction of pull of the six extra-ocular eye muscles. We created 3-D animations that (a) show the intra-cranial path of the relevant oculomotor cranial nerves and which muscles are supplied by them, (b) show which muscles are active in each of the ten lines of sight, (c) demonstrate the various malfunctions of oculomotor systems, as well as (d) show the surgical techniques and the challenges in radial optic neurotomies and subretinal surgeries. Most of the 3-D animations were integrated in interactive multimedia teaching programs. Their effectiveness was compared to conventional teaching methods in a comparative study performed at the University of Vienna. We also performed a survey to examine the response of students being taught with the interactive programs. We are currently in the process of placing most of the animations in an interactive web site in order to make them freely available to everyone who is interested. Results: Although learning how to use complex 3-D computer animation and multimedia authoring software can be very time consuming and

  4. CUDA programs for GPU computing of Swendsen-Wang multi-cluster spin flip algorithm: 2D and 3D Ising, Potts, and XY models

    Komura, Yukihiro

    2014-01-01

    We present sample CUDA programs for the GPU computing of the Swendsen-Wang multi-cluster spin flip algorithm. We deal with the classical spin models; the Ising model, the $q$-state Potts model, and the classical XY model. As for the lattice, both the 2D (square) lattice and the 3D (simple cubic) lattice are treated. We already reported the idea of the GPU implementation for 2D models [Comput. Phys. Commun. 183 (2012) 1155-1161]. We here explain the details of sample programs, and discuss the performance of the present GPU implementation for the 3D Ising and XY models. We also show the calculated results of the moment ratio for these models, and discuss phase transitions.

  5. 16-Detector row computed tomographic coronary angiography in patients undergoing evaluation for aortic valve replacement: comparison with catheter angiography

    Manghat, N.E.; Morgan-Hughes, G.J.; Broadley, A.J.; Undy, M.B.; Wright, D.; Marshall, A.J.; Roobottom, C.A

    2006-09-15

    Aim: To evaluate the diagnostic accuracy of 16-detector row computed tomography (CT) in assessing haemodynamically significant coronary artery stenoses in patients under evaluation for aortic stenosis pre-aortic valve replacement. Subjects and methods: Forty consecutive patients under evaluation for severe aortic stenosis and listed for cardiac catheterization before potential aortic valve replacement underwent coronary artery calcium (CAC) scoring and retrospective electrocardiogram (ECG)-gated multi-detector row computed tomographic coronary angiography (MDCTA) using a GE Lightspeed 16-detector row CT within 1 month of invasive coronary angiography (ICA) for comparative purposes. All 13 major coronary artery segments of the American Heart Association model were evaluated for the presence of {>=}50% stenosis and compared to the reference standard. Data were analysed on a segment-by-segment basis and also in 'whole patient' terms. Results: A total of 412/450 segments from 35 patients were suitable for analysis. The overall accuracy of MDCTA for detection of segments with {>=}50% stenosis was high, with a sensitivity of 81.3%, specificity 95.0%, positive predictive value (PPV) 57.8%, and negative predictive value (NPV) 98.4%. On a 'whole-patient' basis, 100% (19/19) of patients with significant coronary disease were correctly identified and there were no false-negatives. Excluding patients with CAC >1000 from the analysis improved the accuracy of MDCTA to: sensitivity 90%, specificity 98.1%, PPV 60%, NPV 99.7%. Conclusion: Non-invasive 16-detector row MDCTA accurately excludes significant coronary disease in patients with severe aortic stenosis undergoing evaluation before aortic valve replacement and in whom ICA can therefore be avoided. Its segment-by-segment accuracy is improved further if CAC > 1000 is used as a gatekeeper to MDCTA.

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

    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.

  7. A fractal approach to the dark silicon problem: a comparison of 3D computer architectures -- standard slices versus fractal Menger sponge geometry

    Herrmann, Richard

    2014-01-01

    The dark silicon problem, which limits the power-growth of future computer generations, is interpreted as a heat energy transport problem when increasing the energy emitting surface area within a given volume. A comparison of two 3D-configuration models, namely a standard slicing and a fractal surface generation within the Menger sponge geometry is presented. It is shown, that for iteration orders $n>3$ the fractal model shows increasingly better thermal behavior. As a consequence cooling pro...

  8. 3D volume assessment techniques and computer-aided design and manufacturing for preoperative fabrication of implants in head and neck reconstruction.

    Patel, Ashish; Otterburn, David; Saadeh, Pierre; Levine, Jamie; Hirsch, David L

    2011-11-01

    Cases in subdisciplines of craniomaxillofacial surgery--corrective jaw surgery, maxillofacial trauma, temporomandibular joint/skull base, jaw reconstruction, and postablative reconstruction-illustrate the ease of use, cost effectiveness, and superior results that can be achieved when using computer-assisted design and 3D volumetric analysis in preoperative surgical planning. This article discusses the materials and methods needed to plan cases, illustrates implementation of guides and implants, and describes postoperative analysis in relation to the virtually planned surgery.

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

    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.

  10. Development of a locally mass flux conservative computer code for calculating 3-D viscous flow in turbomachines

    Walitt, L.

    1982-01-01

    The VANS successive approximation numerical method was extended to the computation of three dimensional, viscous, transonic flows in turbomachines. A cross-sectional computer code, which conserves mass flux at each point of the cross-sectional surface of computation was developed. In the VANS numerical method, the cross-sectional computation follows a blade-to-blade calculation. Numerical calculations were made for an axial annular turbine cascade and a transonic, centrifugal impeller with splitter vanes. The subsonic turbine cascade computation was generated in blade-to-blade surface to evaluate the accuracy of the blade-to-blade mode of marching. Calculated blade pressures at the hub, mid, and tip radii of the cascade agreed with corresponding measurements. The transonic impeller computation was conducted to test the newly developed locally mass flux conservative cross-sectional computer code. Both blade-to-blade and cross sectional modes of calculation were implemented for this problem. A triplet point shock structure was computed in the inducer region of the impeller. In addition, time-averaged shroud static pressures generally agreed with measured shroud pressures. It is concluded that the blade-to-blade computation produces a useful engineering flow field in regions of subsonic relative flow; and cross-sectional computation, with a locally mass flux conservative continuity equation, is required to compute the shock waves in regions of supersonic relative flow.

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

    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.

  12. Computed tomographic cholangiography in the diagnosis of choledocholithiasis; Colangio-TC en el diagnostico de coledocolitiasis

    Lopez-Negrete, L.; Sanchez, J. L.; Garcia-Lozano, J.; Tejeiro, A.; Salas, J. [Hospital Valle del Nalon. Riano-Langreo. Asturias (Spain)

    2001-07-01

    Over a one-year period we performed 32 conventional computed tomography (CT) studies involving the intravenous administration of a contrast material that is cleared by the biliary system (Bilisergol), in patients in presenting clinical or radiological features of choledocholithiasis. The results were compared with the findings from endoscopic retrograde cholangiopancreatography (ERCP) and/or surgery. The sensitivity and specificity of intravenous cholangiography with conventional CT was 92 %. We demonstrate the utility of this widely available study, when performed according to protocol during apnea, with acquisition of thin sections. It is a highly sensitive and specific tool in the diagnosis of choledocholithiasis. (Author) 10 refs.

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

    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.

  14. Hybrid grid-particle methods and Penalization: A Sherman-Morrison-Woodbury approach to compute 3D viscous flows using FFT

    Chatelin, Robin; Poncet, Philippe

    2014-07-01

    Particle methods are very convenient to compute transport equations in fluid mechanics as their computational cost is linear and they are not limited by convection stability conditions. To achieve large 3D computations the method must be coupled to efficient algorithms for velocity computations, including a good treatment of non-homogeneities and complex moving geometries. The Penalization method enables to consider moving bodies interaction by adding a term in the conservation of momentum equation. This work introduces a new computational algorithm to solve implicitly in the same step the Penalization term and the Laplace operators, since explicit computations are limited by stability issues, especially at low Reynolds number. This computational algorithm is based on the Sherman-Morrison-Woodbury formula coupled to a GMRES iterative method to reduce the computations to a sequence of Poisson problems: this allows to formulate a penalized Poisson equation as a large perturbation of a standard Poisson, by means of algebraic relations. A direct consequence is the possibility to use fast solvers based on Fast Fourier Transforms for this problem with good efficiency from both the computational and the memory consumption point of views, since these solvers are recursive and they do not perform any matrix assembling. The resulting fluid mechanics computations are very fast and they consume a small amount of memory, compared to a reference solver or a linear system resolution. The present applications focus mainly on a coupling between transport equation and 3D Stokes equations, for studying biological organisms motion in a highly viscous flows with variable viscosity.

  15. Sectional depiction of the pelvic floor by CT, MR imaging and sheet plastination: computer-aided correlation and 3D model

    Beyersdorff, D.; Taupitz, M.; Hamm, B. [Dept. of Radiology, Humboldt Univ., Berlin (Germany); Schiemann, T. [Inst. for Mathematics and Computer Science in Medicine, University of Hamburg (Germany); Kooijman, H. [Philips Medical Systems, Hamburg (Germany); Nicolas, V. [Dept. of Radiology and Nuclear Medicine, BG Kliniken Bergmannsheil, Bochum (Germany)

    2001-04-01

    The structures of the pelvic floor are clinically important but difficult to assess. To facilitate the understanding of the complicated pelvic floor anatomy on sectional images obtained by CT and MR imaging, and to make the representation more vivid, a computer-aided 3D model was created from a male and a female torso to develop a teaching tool. A male and a female cadaver torso were investigated by means of CT, MR imaging, and serial-section sheet plastination. A 3D reconstruction of the pelvic floor and adjacent structures was performed by fusion of CT and MR imaging data sets with sheet plastination sections. Corresponding sections from all three methods could be compared and visualized in their 3D context. Sheet plastination allows distinction of connective tissue, muscles, and pelvic organs down to a microscopic level. In combination with CT, MR imaging, and sheet plastination a 3D model of the pelvic floor offers a better understanding of the complex pelvic anatomy. This knowledge may be applied in the diagnostic imaging of urinary incontinence or prolapse and prior to prostate surgery. (orig.)

  16. Teaching Reform and Practice in Engineering Drawing Based on 3D Modeling with Computer%Teaching Reform and Practice in Engineering Drawing Based on 3D Modeling with Computer

    WANG Jian-hua; HAO Yu-xin

    2011-01-01

    Based on the necessity of three dimensional modeling with computer in teaching reform, this paper is the summarization of reform practice of teaching engineering drawing in our institute. The teaching reform begins with three dimensional modeling that used computer instead of board. On the basis of target of teaching reform, set of teaching content, arrangement of class hour and teaching method, the research of teaching practice have been done, and very good effects in teaching of engineering drawing have been achieved.

  17. 3-D waveform tomography sensitivity kernels for anisotropic media

    Djebbi, R.

    2014-01-01

    The complications in anisotropic multi-parameter inversion lie in the trade-off between the different anisotropy parameters. We compute the tomographic waveform sensitivity kernels for a VTI acoustic medium perturbation as a tool to investigate this ambiguity between the different parameters. We use dynamic ray tracing to efficiently handle the expensive computational cost for 3-D anisotropic models. Ray tracing provides also the ray direction information necessary for conditioning the sensitivity kernels to handle anisotropy. The NMO velocity and η parameter kernels showed a maximum sensitivity for diving waves which results in a relevant choice of those parameters in wave equation tomography. The δ parameter kernel showed zero sensitivity; therefore it can serve as a secondary parameter to fit the amplitude in the acoustic anisotropic inversion. Considering the limited penetration depth of diving waves, migration velocity analysis based kernels are introduced to fix the depth ambiguity with reflections and compute sensitivity maps in the deeper parts of the model.

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

    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.

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

    Shiraz Pasha

    2016-01-01

    Full Text Available 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.

  20. Correlation between computed tomographic and magnetic resonance imaging findings of parenchymal lung diseases

    Barreto, Miriam Menna; Rafful, Patricia Piazza [Department of Radiology, Federal University of Rio de Janeiro, Rio de Janeiro (Brazil); Rodrigues, Rosana Souza [Department of Radiology, Federal University of Rio de Janeiro, Rio de Janeiro (Brazil); D’Or Institute for Research and Education, Rio de Janeiro, RJ (Brazil); Zanetti, Gláucia [Department of Radiology, Federal University of Rio de Janeiro, Rio de Janeiro (Brazil); Hochhegger, Bruno [Complexo Hospitalar Santa Casa de Misericórdia de Porto Alegre, Porto Alegre, RS (Brazil); Souza, Arthur Soares [Department of Radiology, Medical School of Rio Preto (FAMERP) and Ultra X, São José do Rio Preto, SP (Brazil); Guimarães, Marcos Duarte [Department of Imaging, Hospital AC Camargo, São Paulo, SP (Brazil); Marchiori, Edson, E-mail: edmarchiori@gmail.com [Department of Radiology, Federal University of Rio de Janeiro, Rio de Janeiro (Brazil)

    2013-09-15

    Computed tomography (CT) is considered to be the gold standard method for the assessment of morphological changes in the pulmonary parenchyma. Although its spatial resolution is lower than that of CT, MRI offers the advantage of characterizing different aspects of tissue based on the degree of contrast on T1-weighted image (WI) and T2-WI. In this article, we describe and correlate the MRI and CT features of several common patterns of parenchymal lung disease (air trapping, atelectasis, bronchiectasis, cavitation, consolidation, emphysema, ground-glass opacities, halo sign, interlobular septal thickening, masses, mycetoma, nodules, progressive massive fibrosis, reverse halo sign and tree-in-bud pattern). MRI may be an alternative modality for the collection of morphological and functional information useful for the management of parenchymal lung disease, which would help reduce the number of chest CT scans and radiation exposure required in patients with a variety of conditions.

  1. Imaging of Anal Fistulas: Comparison of Computed Tomographic Fistulography and Magnetic Resonance Imaging

    Liang, Changhu [Shandong Medical Imaging Research Institute, Shandong University, Jinan 250021 (China); Lu, Yongchao [Traditional Chinese Medicine Department, Provincial Hospital Affiliated to Shandong University, Jinan 250021 (China); Zhao, Bin [Shandong Medical Imaging Research Institute, Shandong University, Jinan 250021 (China); Du, Yinglin [Shandong Provincial Center for Disease Control and Prevention, Public Health Institute, Jinan 250014 (China); Wang, Cuiyan [Shandong Medical Imaging Research Institute, Shandong University, Jinan 250021 (China); Jiang, Wanli [Department of Radiology, Taishan Medical University, Taian 271000 (China)

    2014-07-01

    The primary importance of magnetic resonance (MR) imaging in evaluating anal fistulas lies in its ability to demonstrate hidden areas of sepsis and secondary extensions in patients with fistula in ano. MR imaging is relatively expensive, so there are many healthcare systems worldwide where access to MR imaging remains restricted. Until recently, computed tomography (CT) has played a limited role in imaging fistula in ano, largely owing to its poor resolution of soft tissue. In this article, the different imaging features of the CT and MRI are compared to demonstrate the relative accuracy of CT fistulography for the preoperative assessment of fistula in ano. CT fistulography and MR imaging have their own advantages for preoperative evaluation of perianal fistula, and can be applied to complement one another when necessary.

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

    Remy-Jardin, M.; Remy, J.; Farre, I.; Marquette, C.H. (Department of Radiology, Hopital Calmette, CHRU, Lille (France))

    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.

  3. Simulation of dynamic behaviour of a digital displacement motor using transient 3d computational fluid dynamics analysis

    Rømer, Daniel; Johansen, Per; Pedersen, Henrik C.

    2013-01-01

    A fast rotating 1500 rpm radial piston digital displacement motor connected to a 350 bar high pressure manifold is simulated by means of transient 3D CFD analysis of a single pressure chamber. The analysis includes dynamic piston and valve movement, influencing the boundaries of the fluid domain...... the simulation using layering zones as required by the moving fluid boundaries. The effect of cavitation at low pressures is included by implementing a pressure dependent density, based on an effective bulk modulus model. In addition, pressure dependent oil viscosity is included in the analysis. As a result...... of the CFD analysis, the dynamic response of the pressure chamber and valve movement of a digital displacement motor is presented, along with the total efficiency of a multi-chamber motor at full and partial displacement. Simulation predicts that pressure over- and undershoot may be reduced to a few percent...

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

    Ghatwary, Tamer M. H.; Patterson, Benjamin O.; Karthikesalingam, Alan; Hinchliffe, Robert J.; Loftus, Ian M. [St. George' s Vascular Institute, St. George' s Hospital, Department of Outcomes Research (United Kingdom); Morgan, Robert [St. George' s Hospital, Department of Radiology (United Kingdom); Thompson, Matt M.; Holt, Peter J. E., E-mail: pholt@sgul.ac.uk [St. George' s Vascular Institute, St. George' s Hospital, Department of Outcomes Research (United Kingdom)

    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.

  5. Computed tomographic evaluation of the proximal femur: A predictive classification in displaced femoral neck fracture management

    Narender Kumar Magu

    2014-01-01

    Full Text Available Background: Femoral neck fracture is truly an enigma due to the high incidence of avascular necrosis and nonunion. Different methods have been described to determine the size of the femoral head fragment, as a small head has been said to be associated with poor outcome and nonunion due to inadequate implant purchase in the proximal fragment. These methods were two dimensional and were affected by radiography techniques, therefore did not determine true head size. Computed tomography (CT is an important option to measure true head size as images can be obtained in three dimensions. Henceforth, we subjected patients to CT scan of hip in cases with displaced fracture neck of femur. The study aims to define the term "small head or inadequate size femoral head" objectively for its prognostic significance. Materials and Methods: 70 cases of displaced femoral neck fractures underwent CT scan preoperatively for proximal femoral geometric measurements of both hips. Dual energy X-ray absorptiometry scan was done in all cases. Patients were treated with either intertrochanteric osteotomy or lag screw osteosynthesis based on the size of the head fragment on plain radiographs. Results: The average femoral head fragment volume was 57 cu cm (range 28.3-84.91 cu cm; standard deviation 14 cu cm. Proximal fragment volume of >43 cu cm was termed adequate size (type I and of ≤43 cu cm as small femoral head (type II. Fractures which united (n = 54 had a relatively large average head size (59 cu cm when compared to fractures that did not (n = 16, which had a small average head size (49 cu cm and this difference was statistically significant. In type I fractures union rate was comparable in both osteotomy and lag screw groups (P > 0.05. Lag screw fixation failed invariably, while osteotomy showed good results in type II fractures (P < 0.05. Conclusion: Computed tomography scan of the proximal femur is advisable for measuring true size of head fragment. An objective

  6. Computed tomographic angiography criteria in the diagnosis of brain death - comparison of sensitivity and interobserver reliability of different evaluation scales

    Sawicki, Marcin; Walecka, A. [Pomeranian Medical University, Department of Diagnostic Imaging and Interventional Radiology, Szczecin (Poland); Bohatyrewicz, R.; Solek-Pastuszka, J. [Pomeranian Medical University, Clinic of Anesthesiology and Intensive Care, Szczecin (Poland); Safranow, K. [Pomeranian Medical University, Department of Biochemistry and Medical Chemistry, Szczecin (Poland); Walecki, J. [The Centre of Postgraduate Medical Education, Warsaw (Poland); Rowinski, O. [Medical University of Warsaw, 2nd Department of Clinical Radiology, Warsaw (Poland); Czajkowski, Z. [Regional Joint Hospital, Szczecin (Poland); Guzinski, M. [Wroclaw Medical University, Department of General Radiology, Interventional Radiology and Neuroradiology, Wroclaw (Poland); Burzynska, M. [Wroclaw Medical University, Department of Anesthesiology and Intensive Therapy, Wroclaw (Poland); Wojczal, J. [Medical University of Lublin, Department of Neurology, Lublin (Poland)

    2014-08-15

    The standardized diagnostic criteria for computed tomographic angiography (CTA) in diagnosis of brain death (BD) are not yet established. The aim of the study was to compare the sensitivity and interobserver agreement of the three previously used scales of CTA for the diagnosis of BD. Eighty-two clinically brain-dead patients underwent CTA with a delay of 40 s after contrast injection. Catheter angiography was used as the reference standard. CTA results were assessed by two radiologists, and the diagnosis of BD was established according to 10-, 7-, and 4-point scales. Catheter angiography confirmed the diagnosis of BD in all cases. Opacification of certain cerebral vessels as indicator of BD was highly sensitive: cortical segments of the middle cerebral artery (96.3 %), the internal cerebral vein (98.8 %), and the great cerebral vein (98.8 %). Other vessels were less sensitive: the pericallosal artery (74.4 %), cortical segments of the posterior cerebral artery (79.3 %), and the basilar artery (82.9 %). The sensitivities of the 10-, 7-, and 4-point scales were 67.1, 74.4, and 96.3 %, respectively (p < 0.001). Percentage interobserver agreement in diagnosis of BD reached 93 % for the 10-point scale, 89 % for the 7-point scale, and 95 % for the 4-point scale (p = 0.37). In the application of CTA to the diagnosis of BD, reducing the assessment of vascular opacification scale from a 10- to a 4-point scale significantly increases the sensitivity and maintains high interobserver reliability. (orig.)

  7. Relationship between cerebrospinal fluid flow through the ventriculo-peritoneal shunt and computed tomographic images of hydrocephalic patients

    Ikeda, Kiyonobu; Itoh, Haruhide; Someya, Shigeru; Yamamoto, Shinjiro

    1988-04-01

    Quantitative measurements of cerebrospinal fluid flow through the ventriculo-peritoneal shunt using radioisotope were carried out on 34 hydrocepalic patients (18 children and 16 adults) and the relationship between the flow rates and the computed tomographic (CT) images was studied. 1) The flow rates in the prone position was 0.04 - 0.20(mean +- SD, 0.10 +- 0.05) ml/min in 13 patients whose shunt systems were functioning adequately. There was a good correlation between the flow rates and closing pressures of the shunt valves. 2) The 21 patients with malfunctioning shunt systems were devided into two groups as follows; the obstruction or lower flow group in which the shunt flow was in 0 approx. 0.05 ml/min and the over-flow groups with rates over 0.20 ml/min. In the former group, there were 3 cases in which the shunt flow in a sitting position was very low and the cause of the malfunction was thought to be placement of an inadequate system with a higher pressure valve. 3) In 4 cases of 5 children in which the ventricles were of normal size during shunt malfunction, their ventricular sizes on CT images changed to small or slit-like ventricles after shunt revision. 4) A few cases of hydrocephalic adults, in which the shunt-catheters were thought to be obstructed with no shunt flow in the prone and sitting positions showing no progressive dilatation of the ventricles on CT images, were diagnosed with the added findings of RI cisternography as shunt-dependent arrested hydrocephalus. In the diagnosis of shunt malfunction and selection of the most adequate system in shunt revision, it is necessary to analyze together the data on CT images, quantitative measurement of shunt flow rates and RI cisternography as well as the clinical manifestations.

  8. Computed tomographic demonstrations of HIV seropositive pulmonary tuberculosis and their relationship with CD4+T-lymphocyte count

    ZHANG Yu-zhong; LI Hong-jun; CHENG Jing-liang; WU Hao; BAO Dong-ying

    2011-01-01

    Background Factors of cell-mediated immunity and allergy together play their roles in the pathogenesis of pulmonary tuberculosis (PTB) and its prognosis. The purpose of this study was to investigate the computed tomographic demonstrations of HIV seropositive PTB and the relationship between its pathogenesis and CD4+ T-lymphocyte count.Methods The documented CT images of a total of 44 patients with HIV seropositive PTB, definitely diagnosed by etiological or pathological examinations, their clinical data and their CD4+ T-lymphocyte count were retrospectively reviewed.Results There were 15 cases of miliary tuberculosis, accounting for 34.1% of the total cases; 15 cases of nodular tuberculosis, 34.1%; 6 cases of ground-glass opacity, 13.6%; 5 cases of cord-liked fiber shadows, 11.4%; 16 cases of flaky and flocculating shadows, 36.4%; 5 cases of cavitation, 11.4%; 5 cases of tumor shadows, 11.4%; 2 cases of pleural thickening, 4.5% and 11 cases of pleural effusion, 25.0%; 1 case of calcification, 2.3%; 16 cases of lymphadenectasis,36.4%. The foci were located around the pulmonary hilum, anterior segment of superior lobe, basal segment of inferior lobe, medial lobe and lingual lobe. CD4+ T-lymphocyte count was closely related to the imaging demonstrations of HIV seropositive PTB.Conclusions CT scanning can demonstrate various signs of PTB. CD4+ T-lymphocyte level determines the variety of imaging demonstrations of HIV seropositive PTB and its prognosis.

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

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

    2010-06-01

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

  10. Femoral neck anteversion, acetabular anteversion and combined anteversion in the normal Indian adult population: A computed tomographic study

    Maheshwari Aditya

    2010-01-01

    Full Text Available Background: Abnormal femoral neck anteversion (FNA and/or acetabulum anteversion (AA have long been implicated in the etiogenesis of hip osteoarthritis (OA, developmental dysplasia of the hip (DDH, and impingement, instability and wear in total hip arthroplasty (THA. Since studies on the Indian population are sparse on this topic, the purpose of this study was to report the normal values of FNA, AA and the combined anteversion (CA= FNA+ AA in Indian adults. Materials and Methods: FNA, AA and CA were prospectively measured in 172 normal hips in 86 Indian adults using standardized computed tomographic (CT methods and this data was compared with the established Western values. Results: The median values and interquartile ranges were 8 o (6.5-10.0 o for FNA, 19 o (16.0-22.0 o for AA and 27 o (23.5-30.0 o for CA. AA and CA values were significantly (P< 0.05 lower in males, and there was also a trend towards lower FNA in males. Although a negative correlation was observed between the FNA and AA, this was not strong and may not be clinically relevant. Conclusion: When compared with the Western data, the FNA values were 3-12 o lower and the CA values were 3-5 o lower in Indian adults. The AA values were comparable, but were skewed towards the higher side. Further studies are needed to assess the clinical relevance of our basic science data in pathogenesis of OA, and to validate it in relation to hip surgeries like corrective osteotomies and THA.

  11. Tiny staining spots in liver cirrhosis associated with HCV infection observed by computed tomographic hepatic arteriography. Follow-up study

    Tsuchiyama, Tomoya; Terasaki, Shuichi; Kaneko, Shuichi; Kaji, Kyosuke; Kobayashi, Kenichi; Matsui, Osamu [Kanazawa Univ. (Japan). Hospital

    2002-10-01

    It is important to distinguish small lesions with increased arterial perfusion observed by computed tomographic arteriography (CT-A) from hepatocellular carcinoma (HCC). However, the clinical characteristics and prognosis of such lesions have not been clarified. We retrospectively examined 200 patients with cirrhosis related to hepatitis C virus (HCV) infection who had undergone both CT-A and CT arterioportography between 1995 and 1998, and found 80 tiny staining spots (TSS)s, with a diameter of 5-10 mm, by CT-A (35 patients). The mean TSS observation period was 29.0 months. If the major axis was larger than 10 mm and showed a 1.5-fold or more increase, the lesion was regarded as tumor growth (TG). The TSS lesions were divided into two groups according to whether the patient had or did not have HCC. The prognosis of TSS was classified into three groups; HCC-suspected group, nontumor group, and unclassified group, in which TG was negative although transcatheter arterial embolization (TAE) had been performed. Of the 40 TSSs in 14 patients without HCC, 2 (5%) were suspected as HCC. Of the 40 TSSs in 21 patients with HCC, 13 (32.5%) were suspected as HCC. There were no significant differences in the size, position, and morphology of TSSs among the three prognostic groups. Of the 7 TSSs with a high signal intensity on T2-weighted magnetic resonance (MR) images, 5 were in the HCC-suspected group. We recommend early treatment of TSSs accompanying HCC or showing features of malignancy at the imaging workup. (author)

  12. Rapid estimation of split renal function in kidney donors using software developed for computed tomographic renal volumetry

    Kato, Fumi, E-mail: fumikato@med.hokudai.ac.jp [Department of Radiology, Hokkaido University Graduate School of Medicine, N15, W7, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Kamishima, Tamotsu, E-mail: ktamotamo2@yahoo.co.jp [Department of Radiology, Hokkaido University Graduate School of Medicine, N15, W7, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Morita, Ken, E-mail: kenordic@carrot.ocn.ne.jp [Department of Urology, Hokkaido University Graduate School of Medicine, N15, W7, Kita-ku, Sapporo, 060-8638 (Japan); Muto, Natalia S., E-mail: nataliamuto@gmail.com [Department of Radiology, Hokkaido University Graduate School of Medicine, N15, W7, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Okamoto, Syozou, E-mail: shozo@med.hokudai.ac.jp [Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, N15, W7, Kita-ku, Sapporo, 060-8638 (Japan); Omatsu, Tokuhiko, E-mail: omatoku@nirs.go.jp [Department of Radiology, Hokkaido University Graduate School of Medicine, N15, W7, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Oyama, Noriko, E-mail: ZAT04404@nifty.ne.jp [Department of Radiology, Hokkaido University Graduate School of Medicine, N15, W7, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Terae, Satoshi, E-mail: saterae@med.hokudai.ac.jp [Department of Radiology, Hokkaido University Graduate School of Medicine, N15, W7, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Kanegae, Kakuko, E-mail: IZW00143@nifty.ne.jp [Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, N15, W7, Kita-ku, Sapporo, 060-8638 (Japan); Nonomura, Katsuya, E-mail: k-nonno@med.hokudai.ac.jp [Department of Urology, Hokkaido University Graduate School of Medicine, N15, W7, Kita-ku, Sapporo, 060-8638 (Japan); Shirato, Hiroki, E-mail: shirato@med.hokudai.ac.jp [Department of Radiology, Hokkaido University Graduate School of Medicine, N15, W7, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan)

    2011-07-15

    Purpose: To evaluate the speed and precision of split renal volume (SRV) measurement, which is the ratio of unilateral renal volume to bilateral renal volume, using a newly developed software for computed tomographic (CT) volumetry and to investigate the usefulness of SRV for the estimation of split renal function (SRF) in kidney donors. Method: Both dynamic CT and renal scintigraphy in 28 adult potential living renal donors were the subjects of this study. We calculated SRV using the newly developed volumetric software built into a PACS viewer (n-SRV), and compared it with SRV calculated using a conventional workstation, ZIOSOFT (z-SRV). The correlation with split renal function (SRF) using {sup 99m}Tc-DMSA scintigraphy was also investigated. Results: The time required for volumetry of bilateral kidneys with the newly developed software (16.7 {+-} 3.9 s) was significantly shorter than that of the workstation (102.6 {+-} 38.9 s, p < 0.0001). The results of n-SRV (49.7 {+-} 4.0%) were highly consistent with those of z-SRV (49.9 {+-} 3.6%), with a mean discrepancy of 0.12 {+-} 0.84%. The SRF also agreed well with the n-SRV, with a mean discrepancy of 0.25 {+-} 1.65%. The dominant side determined by SRF and n-SRV showed agreement in 26 of 28 cases (92.9%). Conclusion: The newly developed software for CT volumetry was more rapid than the conventional workstation volumetry and just as accurate, and was suggested to be useful for the estimation of SRF and thus the dominant side in kidney donors.

  13. Detection of unruptured cerebral artery aneurysms by MRA at 3.0 tesla: comparison with multislice helical computed tomographic angiography

    Numminen, Jussi; Porras, Matti; Kangasniemi, Marko (Dept. of Radiology, Helsinki Medical Imaging Center, Helsinki Univ. Central Hospital, Helsinki (Finland)), email: jussi.numminen@hus.fi; Tarkiainen, Antti (Advanced Magnetic Imaging Center, Helsinki Univ. of Technology, Espoo (Finland)); Niemelae, Mika; Hernesniemi, Juha (Dept. of Neurosurgery, Helsinki Univ. Central Hospital, Helsinki (Finland))

    2011-07-15

    Background: Computed tomographic angiography (CTA) has become the primary non-invasive method for detection of cerebral artery aneurysms in many neurovascular centers. Purpose: To compare MR-angiography at a 3.0 tesla (3T) scanner to CTA in the detection of unruptured intracranial aneurysms. Material and Methods: CTA and 3T MRA data from 60 patients were evaluated. CTA was obtained with a 4-16-row helical CT-scanner after administration of 120 cc intravenous contrast agent, MRA was performed by a 3T MR-scanner using time-of-flight pulse sequence. Results: Fifty-five cerebral artery aneurysms were detected by MRA and 47 aneurysms by CTA. Most of the aneurysms detected by MRA but not by CTA were small internal carotid artery (ICA) aneurysms. Bone structures and venous enhancement deteriorated CTA accuracy, especially in skull base. In one patient a fairly large anterior communicating artery aneurysm was not visible in MRA due to spin saturation, although it was clearly visualized in CTA. After contrast injection the aneurysm was also seen in MRA. Although the overall image quality of MRA and CTA were comparable, MRA was more susceptible to artifacts and thus re-formatted surface-shaded volume rendered 3-dimensional images of aneurysms from MRA were inferior compared to those from CTA. Conclusion: MRA at 3T appears to be at least as sensitive as CTA in the detection of unruptured cerebral artery aneurysms, however image quality control is crucial and contrast agent enhances visualization of complex and large aneurysms

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

    Junko Matsuyama

    2014-01-01

    Full Text Available 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.

  15. Computed tomographic characteristics of interval and post screen carcinomas in lung cancer screening

    Scholten, Ernst T. [University Medical Centre, Department of Radiology, Utrecht (Netherlands); Kennemer Gasthuis, Department of Radiology, Haarlem (Netherlands); Horeweg, Nanda [Erasmus University Medical Centre, Department of Public Health, Rotterdam (Netherlands); Erasmus University Medical Centre, Department of Pulmonary Medicine, Rotterdam (Netherlands); Koning, Harry J. de [Erasmus University Medical Centre, Department of Public Health, Rotterdam (Netherlands); Vliegenthart, Rozemarijn [University of Groningen, University Medical Centre Groningen, Department of Radiology, Groningen (Netherlands); University of Groningen, University Medical Centre Groningen, Center for Medical Imaging-North East Netherlands, Groningen (Netherlands); Oudkerk, Matthijs [University of Groningen, University Medical Centre Groningen, Center for Medical Imaging-North East Netherlands, Groningen (Netherlands); Mali, Willem P.T.M.; Jong, Pim A. de [University Medical Centre, Department of Radiology, Utrecht (Netherlands)

    2015-01-15

    To analyse computed tomography (CT) findings of interval and post-screen carcinomas in lung cancer screening. Consecutive interval and post-screen carcinomas from the Dutch-Belgium lung cancer screening trial were included. The prior screening and the diagnostic chest CT were reviewed by two experienced radiologists in consensus with knowledge of the tumour location on the diagnostic CT. Sixty-one participants (53 men) were diagnosed with an interval or post-screen carcinoma. Twenty-two (36 %) were in retrospect visible on the prior screening CT. Detection error occurred in 20 cancers and interpretation error in two cancers. Errors involved intrabronchial tumour (n = 5), bulla with wall thickening (n = 5), lymphadenopathy (n = 3), pleural effusion (n = 1) and intraparenchymal solid nodules (n = 8). These were missed because of a broad pleural attachment (n = 4), extensive reticulation surrounding a nodule (n = 1) and extensive scarring (n = 1). No definite explanation other than human error was found in two cases. None of the interval or post-screen carcinomas involved a subsolid nodule. Interval or post-screen carcinomas that were visible in retrospect were mostly due to detection errors of solid nodules, bulla wall thickening or endobronchial lesions. Interval or post-screen carcinomas without explanation other than human errors are rare. (orig.)

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

    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 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.

  17. Prevalence of incidental maxillary sinus pathologies in dental patients on cone-beam computed tomographic images

    Mamta Raghav

    2014-01-01

    Full Text Available Objectives: The aim of the present study was to infer and to record the prevalence of incidental maxillary sinus pathologies in patients presenting with dental problems using the cone-beam computed tomography (CBCT scans performed for maxillofacial diagnostic purposes. Materials and Methods: This retrospective study has evaluated 201 patients (402 maxillary sinuses consecutive CBCT for various incidental maxillary sinus pathologies by two observers. Pathologic findings were categorized as mucosal thickening (MT, opacification (OPA, polypoidal-mucosal thickening (PT, others (antrolith and discontinuity of the sinus fl oor and no pathologic findings. Correlations for pathologic findings and the factors of age and gender were calculated. Results: The prevalence for total incidental findings is 59.7%. The present study showed MT (35.1% as most prevalent finding followed by OPA in (16.6%, PT in 7.2% and others in 0.7%. There was no statistically significant difference between gender and between the age groups. There was no statistically significant difference between different indications groups for CBCT scans. Conclusions: The incidental maxillary sinus abnormalities are highly prevalent in the asymptomatic dental patients; hence oral radiologists should be aware of these incidental findings and comprehensively evaluate the entire captured CBCT volume, which can help in early diagnosis, treatment and follow-up of the patient.

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

    Deglint, Hanford J; Rangayyan, Rangaraj M; Ayres, Fábio J; Boag, Graham S; Zuffo, Marcelo K

    2007-09-01

    Segmentation of the tumor in neuroblastoma is complicated by the fact that the mass is almost always heterogeneous in nature; furthermore, viable tumor, necrosis, and normal tissue are often intermixed. Tumor definition and diagnosis require the analysis of the spatial distribution and Hounsfield unit (HU) values of voxels in computed tomography (CT) images, coupled with a knowledge of normal anatomy. Segmentation and analysis of the tissue composition of the tumor can assist in quantitative assessment of the response to therapy and in the planning of the delayed surgery for resection of the tumor. We propose methods to achieve 3-dimensional segmentation of the neuroblastic tumor. In our scheme, some of the normal structures expected in abdominal CT images are delineated and removed from further consideration; the remaining parts of the image volume are then examined for tumor mass. Mathematical morphology, fuzzy connectivity, and other image processing tools are deployed for this purpose. Expert knowledge provided by a radiologist in the form of the expected structures and their shapes, HU values, and radiological characteristics are incorporated into the segmentation algorithm. In this preliminary study, the methods were tested with 10 CT exams of four cases from the Alberta Children's Hospital. False-negative error rates of less than 12% were obtained in eight of 10 exams; however, seven of the exams had false-positive error rates of more than 20% with respect to manual segmentation of the tumor by a radiologist.

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

    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.

  20. Computed tomographic differentiation between alcoholic and gallstone pancreatitis: Significance of distribution of infiltration or fluid collection

    Young-Sun Kim; Yongsoo Kim; Sung-Kyu Kim; Hyunchul Rhim

    2006-01-01

    AIM: To evaluate the usefulness of various computed tomography (CT) findings including distribution of infiltration or fluid collection in differentiating the major etiologies of acute pancreatitis.METHODS: We reviewed 75 relatively severe cases of acute pancreatitis of alcoholic (n=43) or biliary stone(n=32) etiology having infiltration or fluid collection on CT. We compared the pancreatic size, CT grading,presence or absence of biliary calculi, and dilatation of pancreatic or bile duct. We also evaluated degree and the distribution of infiltration and fluid collection in each group.RESULTS: The sizes of pancreas were not different between alcohol group and stone group. Alcohol group showed higher CT grading than stone group (P<0.05). Presence of biliary stone and duct dilatation was statistically significant in differentiating etiology (P <0.05). Alcohol group showed significantly prominent peripancreatic pathology than stone group only in left peritoneal compartment (P = 0.020).CONCLUSION: Alcoholic pancreatitis tends to form more prominent peripancreatic changes than gallstone pancreatitis in relatively severe cases. This is evident on the anterior aspect of left abdomen. Although clinical history and some CT findings usually are a major determinant of the etiology, this pattern of peripancreatic pathology may have an ancillary role in determining the etiologies of acute pancreatitis in the equivocal cases.

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

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

    2014-01-01

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

  2. Computed tomographic findings of abdominal complications of Crohn's disease - pictorial essay

    Zissin, R. [Tel-Aviv Univ., Dept. of Diagnostic Imaging, Sapir Medical Center, Kfar Saba, Sackler Faculty of Medicine, Tel Aviv (Israel)]. E-mail: zisinrivka@clalit.org.il; Hertz, M. [Tel-Aviv Univ., Dept. of Diagnostic Imaging, Chaim Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv (Israel); Osadchy, A. [Tel-Aviv Univ., Dept. of Diagnostic Imaging, Sapir Medical Center, Kfar Saba, Sackler Faculty of Medicine, Tel Aviv (Israel); Novis, B. [Tel-Aviv Univ., Dept. of Gastroenterology, Sapir Medical Center, Kfar Saba, Sackler Faculty of Medicine, Tel Aviv (Israel); Gayer, G. [Tel-Aviv Univ., Department of Diagnostic Imaging, Assaf Harode Medical Center, Zrifin, Sackler Faculty of Medicine, Tel Aviv (Israel)

    2005-02-15

    Crohn's disease (CD) is a chronic, transmural, inflammatory disease of the gastrointestinal tract (CIT) most often affecting the terminal ileum and colon. Diarrhea, abdominal pain, anorexia, nausea, and weight loss are the most common clinical symptoms. Abdominal complications of CD, both intestinal and extraintestinal, are frequent and variable. The most common intestinal complications include ileocolitis with external or internal fistulas and abscess formation, strictures, and bowel obstruction. Less common are free perforation, intussusception, and malignancy. The extraintestinal complications include nephrolithiasis, cholelithiasis, fatty liver, portal vein gas, and thromboembolic events. Nowadays, computed tomography (CT) provides superb anatomic detail and diagnostic accuracy of various intra-abdominal pathological processes, and it thus has become an essential diagnostic tool in the evaluation and management of patients wit known CD for the assessment of bowel wall involvement, the mesenteric extent of the disease, and inn-abdominal complications. In addition, as CT is frequently performed to evaluate patients with acute abdomen, it may encounter clinically unsuspected complications in patients with CD. This article reviews the CT features of various intra-abdominal complications of CD. (author)

  3. Intention tremor after head injury. Clinical features and computed tomographic findings

    Iwadate, Yasuo; Saeki, Naokatsu; Namba, Hiroki; Odaki, Masaru; Oka, Nobuo.

    1989-02-01

    Eight cases of intention tremor as a late complication of head injury were investigated. The patients ranged in age from 3 to 24 years. All received severe head injuries and lapsed into coma immediately afterward (Glasgow Coma Scale scores /le/8). Six patients exhibited decerebration or decortication. Hemiparesis was present in six cases and oculomotor nerve palsy in four. In the chronic stage, all patients displayed some degree of impairment of higher cortical function and five had dysarthria and/or ataxia. Initial computed tomography (CT) scans within 3 hours after the injury were obtained in five cases, of which four showed a hemorrhagic lesion in the midbrain or its surroundings. Other CT findings were diffuse cerebral swelling (four cases), intraventricular hemorrhage (three), and multiple hemorrhagic lesions (two). In the chronic stage, generalized cortical atrophy or ventricular enlargement was noted in five cases. These clinical features and CT findings indicate diffuse brain damage as well as midbrain damage and may reflect shearing injury. (author).

  4. Single-photon emission computed tomographic findings and motor neuron signs in amyotrophic lateral sclerosis

    Terao, Shin-ichi; Sobue, Gen; Higashi, Naoki; Takahashi, Masahiko; Suga, Hidemichi; Mitsuma, Terunori [Aichi Medical Univ., Nagakute (Japan)

    1995-03-01

    {sup 123}I-amphetamine-single photon emission computed tomography (SPECT) was performed on 16 patients with amyotrophic lateral sclerosis (ALS) to investigate the correlation between regional cerebral blood flow (rCBF) and upper motor neuron signs. Significant decreased blood flow less than 2 SDs below the mean of controls was observed in the frontal lobe in 4 patients (25%) and in the frontoparietal lobe including the cortical motor area in 4 patients, respectively. The severity of extermity muscular weakness was significantly correlate with decrease in blood flow through the frontal lobe (p<0.05) and through the frontoparietal lobe (p<0.001). A significant correlation was also noted to exist between the severity of bulbar paralysis and decrease in blood flow through the frontoparietal lobe. No correlation, however, was observed between rCBF and severity of spasticity, presence or absence of Babinski`s sign and the duration of illness. Although muscular weakness in the limbs and bulbar paralysis are not pure upper motor neuron signs, the observed reduction in blood flow through the frontal or frontoparietal lobes appears to reflect extensive progression of functional or organic lesions of cortical neurons including the motor area. (author).

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

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

    2016-05-01

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

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

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

    2016-04-06

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

  7. Spontaneous isolated mesenteric fibromatosis: sonographic and computed tomographic findings with pathologic correlation.

    Ko, Sheung-Fat; Lin, Jui-Wei; Ng, Shu-Hang; Huang, Chung-Cheng; Wan, Yung-Liang; Huang, Hsuan-Ying; Sheen-Chen, Shyr-Ming

    2006-08-01

    Eight cases of spontaneous isolated mesenteric fibromatosis (SIMF) were retrospectively reviewed. Clinical presentations included palpable abdominal mass (n = 6), abdominal pain (n = 4), gastrointestinal bleeding (n = 2) and acute abdomen (n = 1). On sonography and computed tomography (CT), eight SIMFs (size range 3 to 24 cm, mean 14.8 cm) were categorized into four morphologic patterns: well-defined inhomogeneous, well-defined homogeneous, well-defined cystic or infiltrative mesenteric mass patterns. Well-defined inhomogeneous SIMF (n = 3) was correlated with the histopathologic finding of bundles of fibroblasts with unevenly intermingled hyaline and/or myxoid degeneration areas, whereas well-defined homogeneous SIMF (n = 2) showed scarce degenerative changes. Well-defined cystic SIMF (n = 2) were ascribed to the presence of large areas of myxoid and cystic degenerations. One SIMF presented as an infiltrative mesenteric mass and the patient died 10 months after diagnosis. Both cases of cystic SIMFs showed tumor recurrences and one patient died after 84 months. The other five patients were cured by radical tumor resection. In summary, sonography, similar to CT, is also useful for evaluating SIMF with protean morphologic features, ascribing to the underlying histopathologic changes with varied degrees of hyaline, myxoid or cystic degenerations.

  8. Expiratory computed tomographic techniques: a cause of a poor rate of change in lung volume.

    Morikawa, Keiko; Okada, Fumito; Mori, Hiromu

    2015-01-01

    Ninety-nine patients (29 males and 70 females; mean age, 57.1 years; range, 22-81 years) were included in this study to evaluate the factors affecting smaller lung volume changes in expiratory high-resolution computed tomography performed to depict air trapping. All patients underwent inspiratory and expiratory chest thin-section CT examinations and pulmonary function tests. Air trapping on CT images was graded subjectively. All variables (age, sex, diagnosis, pulmonary function index, and air trapping score) were compared with the degree of change in lung volume between the inspiratory and expiratory CT examinations. The variables affecting a lower degree of volume change were vital capacity, forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1.0), and the FEV1.0/FVC ratio. Bronchiolitis obliterans was the dominant diagnosis in patients with insufficient degrees of breath holding and in patients with negative air trapping scores despite an abnormal air trapping index. An insufficient degree of lung changes between inspiration and expiration on CT examinations represented bronchiolitis obliterans, which resulted in low FEV1.0 and FEV1.0/FVC values. Changes in the time gap from the announcement of exhalation and breath holding to the start of scanning most effectively indicated air trapping in patients with bronchiolar disorders.

  9. A rare case of maxillary first molar with single root and single canal diagnosed using spiral computed tomographic scan

    Ajay Saxena

    2014-01-01

    Full Text Available Variations in dental anatomy and canal morphology are found in all teeth. Knowledge of these variations, particularly the location and treatment of all canals, plays a key role in the success of endodontic therapy. The presence of extra canals, apical ramification, or lateral canals is commonly encountered, and their incidence and significance have been well-documented. However, the clinician should also be aware of the possibility of the existence of fewer root and/or canal numbers. Here is a case report of left maxillary first permanent molar with a single root and single canal. The goal of this clinical article is to report a maxillary molar with single root and single canal and to highlight the role of spiral computed tomography (SCT as a method to confirm the three-dimensional (3D anatomy of teeth.

  10. 近距离3D人机交互技术研究实现%Research and implementation of 3D human computer interactive technology in close scenario

    刘川; 邬春学

    2015-01-01

    3D human-computer interaction is an amalgamation of computer graphics, virtual reality and pattern recognition, which consists of virtual environment and 3D object recognition. A total solution consisting of virtual environment rendering and 3D object recognition is proposed and applied in the close human-computer interaction scenes, which simulate virtual scenario with the ratio of 1∶1. The research analyses the transformation between virtual environment and reality; three main factors which have influence on stereo display of virtual object have been explored, which include the camera angle, the distance between two cameras in OpenGL and the stereo image pairs generation;3D object recognition is implemented on Intel Perceptual Computing. Experiments show that the solution has excellent 3D effect in simulation virtual scenario with 1∶1 ratio and high gesture recognition rate.%3D人机交互技术是计算机图形学、虚拟现实和模式识别的交叉融合领域,可分为虚拟环境的显示和三维物体识别。该研究将虚拟环境显示和三维物体识别整合成一个完整的解决方案并应用到1∶1模拟虚拟场景的近距离交互。研究了虚拟现实之间的坐标转换;分析了影响虚拟物体立体显示的三个主要因素:OpenGL中摄像机的张角,摄像机间距和立体图像对的产生;并实现了基于Intel Perceptual Computing的三维物体识别。实验结果显示:该方案在1∶1模拟虚拟场景方面具有良好的3D显示效果,同时在手势识别方面有较高的识别率。

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

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

    2015-07-01

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

  12. Computed tomographic morphometry of thoracic pedicles: safety pedicle parameter measurement of the Chinese immature thoracic spine.

    Zheng, Changkun; Huang, Qishan; Hu, Yuezheng; Wang, Xiangyang; Chen, Wei

    2009-12-01

    Our objective was to quantify the morphometric characteristics of the pedicles of the Chinese immature thoracic spine. A total of 120 patients aged 5-14 years underwent standard thoracic computed tomography (CT). The patients were grouped according to age: group 1 (5-8 years of age), group 2 (9-11 years of age) and group 3 (12-14 years of age). Images were reformatted, and multiplanar reconstructions were used to attain images of thoracic pedicles on sagittal, coronal and transverse planes. The measurements included the inner and outer pedicle diameters on the transverse plane, pedicle sagittal diameter, pedicle length and the pedicle angle on the transverse. (1) Pedicle diameters on the transverse plane decreased gradually from T1 to T4 and increased gradually from T5 to T12. The shortest transverse diameter of the thoracic pedicle was T4 or T5. (2) The sagittal diameter was significantly larger than the transverse diameter except at T1. (3) The length of the pedicle from the posterior cortex to the anterior cortex of the vertebra increased from T1 to T12. (4) The pedicle angle decreased gradually from T1 to T8 and became negative below the level of T10. The length of the pedicle changed with age significantly, but the pedicle angle changed with age insignificantly. The success of transpedicular fixation requires a better understanding of morphological features at different ages and reasonable selection of the diameter, length and direction of the pedicle screws based on X-ray and CT films.

  13. [Medical exposure from computed tomographic examination -a recommendation of dosimetry by film method-].

    Yasutomo, Motokatsu; Yagi, Hirofumi

    2002-01-01

    Already, the 30 year have passed since that the CT scanner was developed by Hunsfield. And now above 16,000 sets are at work. On the other hand, as the improvements of image reconstruction algorithm and variations os scan method, the medical exposure is increasing. For example, in the case of computed radiography, medical exposure is stability by using an auto exposure controller but in the case of CT, there is no unit and usually the exposure condition of CT examination are used that of recommended an exposure condition by maker. So the medical exposure greatly differs according to the operators or the kinds of CT scanner. In addition, there is the close connection between the x-ray intensity and the image quality. Especially, in the case of CT scanner there is no saturation of x-ray intensity like the optical density of film screen system because the digital radiographic systems have the wide dynamic range. So the increase in x-ray intensity makes a contribution to improvement of the image quality. But the increase in x-ray intensity makes a contribution to the increase in medical exposure. Therefore it is very important that the CT operators grasp the medical exposure per each CT examination and patient. There are many methods of medical exposure dosimetry on CT examination. But almost all the methods except the film method are impossible to get the medical exposure per each CT examination and patient. So in this paper the film method is recommended. Because the film method is low-priced, simple, easy and immediately shows the medical exposure per each CT examination and patient. Furthermore, it is confirmed that the film method is getting the correct medical exposure because that values gotten by the film method and ionization chamber are almost equivalent.

  14. 3D Surgical Simulation

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

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

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

    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%,x2 =5.705,P < 0.05) and diagnostic accuracy (87% vs.93%,x2 =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%,x2 =17.283.P < 0.001),diagnostic accuracy (93% vs.72%,x2 =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.

  16. PLOT3D user's manual

    Walatka, Pamela P.; Buning, Pieter G.; Pierce, Larry; Elson, Patricia A.

    1990-01-01

    PLOT3D is a computer graphics program designed to visualize the grids and solutions of computational fluid dynamics. Seventy-four functions are available. Versions are available for many systems. PLOT3D can handle multiple grids with a million or more grid points, and can produce varieties of model renderings, such as wireframe or flat shaded. Output from PLOT3D can be used in animation programs. The first part of this manual is a tutorial that takes the reader, keystroke by keystroke, through a PLOT3D session. The second part of the manual contains reference chapters, including the helpfile, data file formats, advice on changing PLOT3D, and sample command files.

  17. 3D computation of an incipient motion of a sessile drop on a rigid surface with contact angle hysteresis

    Linder, Nicklas; Criscione, Antonio; Roisman, Ilia V.; Marschall, Holger; Tropea, Cameron

    2015-12-01

    Contact line phenomena govern a large number of multiphase flows. A reliable description of the contact line dynamics is therefore essential for prediction of such flows. Well-known difficulties of computation of the wetting phenomena include the mesh dependence of the results caused by flow singularity near the contact line and accurate estimation of its propagating velocity. The present study deals with the computational problem arising from the discontinuity in the dependence of the dynamic contact angle on the propagation velocity, associated with the contact angle hysteresis. The numerical simulations are performed using the volume of fluid method. The boundary conditions in the neighborhood of the contact line are switched depending on the value of the computed current local contact angle between a propagating contact line and a pinning condition. The method is applied to the simulation of the deformation and incipient motion of a shedding drop. The model is validated by comparison of the numerical predictions with experimental data.

  18. CosmicPy: Interactive cosmology computations

    Lanusse, Francois; Rassat, Anais; Starck, Jean-Luc

    2016-01-01

    CosmicPy performs simple and interactive cosmology computations for forecasting cosmological parameters constraints; it computes tomographic and 3D Spherical Fourier-Bessel power spectra as well as Fisher matrices for galaxy clustering. Written in Python, it relies on a fast C++ implementation of Four