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Sample records for computed tomographic reconstruction

  1. Direct computation of harmonic moments for tomographic reconstruction

    International Nuclear Information System (INIS)

    Nara, Takaaki; Ito, Nobutaka; Takamatsu, Tomonori; Sakurai, Tetsuya

    2007-01-01

    A novel algorithm to compute harmonic moments of a density function from its projections is presented for tomographic reconstruction. For projection p(r, θ), we define harmonic moments of projection by ∫ π 0 ∫ ∞ -∞ p(r,θ)(re iθ ) n drd θ and show that it coincides with the harmonic moments of the density function except a constant. Furthermore, we show that the harmonic moment of projection of order n can be exactly computed by using n+ 1 projection directions, which leads to an efficient algorithm to reconstruct the vertices of a polygon from projections.

  2. Detectability in the presence of computed tomographic reconstruction noise

    International Nuclear Information System (INIS)

    Hanson, K.M.

    1977-01-01

    The multitude of commercial computed tomographic (CT) scanners which have recently been introduced for use in diagnostic radiology has given rise to a need to compare these different machines in terms of image quality and dose to the patient. It is therefore desirable to arrive at a figure of merit for a CT image which gives a measure of the diagnostic efficacy of that image. This figure of merit may well be dependent upon the specific visual task being performed. It is clearly important that the capabilities and deficiencies of the human observer as well as the interface between man and machine, namely the viewing system, be taken into account in formulating the figure of merit. Since the CT reconstruction is the result of computer processing, it is possible to use this processing to alter the characteristics of the displayed images. This image processing may improve or degrade the figure of merit

  3. Computer tomographs

    International Nuclear Information System (INIS)

    Niedzwiedzki, M.

    1982-01-01

    Physical foundations and the developments in the transmission and emission computer tomography are presented. On the basis of the available literature and private communications a comparison is made of the various transmission tomographs. A new technique of computer emission tomography ECT, unknown in Poland, is described. The evaluation of two methods of ECT, namely those of positron and single photon emission tomography is made. (author)

  4. Effect of noise in computed tomographic reconstructions on detectability

    International Nuclear Information System (INIS)

    Hanson, K.M.

    1982-01-01

    The detectability of features in an image is ultimately limited by the random fluctuations in density or noise present in that image. The noise in CT reconstructions arising from the statistical fluctuations in the one-dimensional input projection measurements has an unusual character owing to the reconstruction procedure. Such CT image noise differs from the white noise normally found in images in its lack of low-frequency components. The noise power spectrum of CT reconstructions can be related to the effective density of x-ray quanta detected in the projection measurements, designated as NEQ (noise-equivalent quanta). The detectability of objects that are somewhat larger than the spatial resolution is directly related to NEQ. Since contrast resolution may be defined in terms of the ability to detect large, low-contrast objects, the measurement of a CT scanner's NEQ may be used to characterize its contrast sensitivity

  5. Segmentation-DrivenTomographic Reconstruction

    DEFF Research Database (Denmark)

    Kongskov, Rasmus Dalgas

    such that the segmentation subsequently can be carried out by use of a simple segmentation method, for instance just a thresholding method. We tested the advantages of going from a two-stage reconstruction method to a one stage segmentation-driven reconstruction method for the phase contrast tomography reconstruction......The tomographic reconstruction problem is concerned with creating a model of the interior of an object from some measured data, typically projections of the object. After reconstructing an object it is often desired to segment it, either automatically or manually. For computed tomography (CT...

  6. Industrial dynamic tomographic reconstruction

    International Nuclear Information System (INIS)

    Oliveira, Eric Ferreira de

    2016-01-01

    The state of the art methods applied to industrial processes is currently based on the principles of classical tomographic reconstructions developed for tomographic patterns of static distributions, or is limited to cases of low variability of the density distribution function of the tomographed object. Noise and motion artifacts are the main problems caused by a mismatch in the data from views acquired in different instants. All of these add to the known fact that using a limited amount of data can result in the presence of noise, artifacts and some inconsistencies with the distribution under study. One of the objectives of the present work is to discuss the difficulties that arise from implementing reconstruction algorithms in dynamic tomography that were originally developed for static distributions. Another objective is to propose solutions that aim at reducing a temporal type of information loss caused by employing regular acquisition systems to dynamic processes. With respect to dynamic image reconstruction it was conducted a comparison between different static reconstruction methods, like MART and FBP, when used for dynamic scenarios. This comparison was based on a MCNPx simulation as well as an analytical setup of an aluminum cylinder that moves along the section of a riser during the process of acquisition, and also based on cross section images from CFD techniques. As for the adaptation of current tomographic acquisition systems for dynamic processes, this work established a sequence of tomographic views in a just-in-time fashion for visualization purposes, a form of visually disposing density information as soon as it becomes amenable to image reconstruction. A third contribution was to take advantage of the triple color channel necessary to display colored images in most displays, so that, by appropriately scaling the acquired values of each view in the linear system of the reconstruction, it was possible to imprint a temporal trace into the regularly

  7. A morphological study of the mandibular molar region using reconstructed helical computed tomographic images

    International Nuclear Information System (INIS)

    Tsuno, Hiroaki; Noguchi, Makoto; Noguchi, Akira; Yoshida, Keiko; Tachinami, Yasuharu

    2010-01-01

    This study investigated the morphological variance in the mandibular molar region using reconstructed helical computed tomographic (CT) images. In addition, we discuss the necessity of CT scanning as part of the preoperative assessment process for dental implantation, by comparing the results with the findings of panoramic radiography. Sixty patients examined using CT as part of the preoperative assessment for dental implantation were analyzed. Reconstructed CT images were used to evaluate the bone quality and cross-sectional bone morphology of the mandibular molar region. The mandibular cortical index (MCI) and X-ray density ratio of this region were assessed using panoramic radiography in order to analyze the correlation between the findings of the CT images and panoramic radiography. CT images showed that there was a decrease in bone quality in cases with high MCI. Cross-sectional CT images revealed that the undercuts on the lingual side in the highly radiolucent areas in the basal portion were more frequent than those in the alveolar portion. This study showed that three-dimensional reconstructed CT images can help to detect variances in mandibular morphology that might be missed by panoramic radiography. In conclusion, it is suggested that CT should be included as an important examination tool before dental implantation. (author)

  8. Reconstruction of computed tomographic image from a few x-ray projections by means of accelerative gradient method

    International Nuclear Information System (INIS)

    Kobayashi, Fujio; Yamaguchi, Shoichiro

    1982-01-01

    A method of the reconstruction of computed tomographic images was proposed to reduce the exposure dose to X-ray. The method is the small number of X-ray projection method by accelerative gradient method. The procedures of computation are described. The algorithm of these procedures is simple, the convergence of the computation is fast, and the required memory capacity is small. Numerical simulation was carried out to conform the validity of this method. A sample of simple shape was considered, projection data were given, and the images were reconstructed from 6 views. Good results were obtained, and the method is considered to be useful. (Kato, T.)

  9. Three dimensional reconstruction of computed tomographic images by computer graphics method

    International Nuclear Information System (INIS)

    Kashiwagi, Toru; Kimura, Kazufumi.

    1986-01-01

    A three dimensional computer reconstruction system for CT images has been developed in a commonly used radionuclide data processing system using a computer graphics technique. The three dimensional model was constructed from organ surface information of CT images (slice thickness: 5 or 10 mm). Surface contours of the organs were extracted manually from a set of parallel transverse CT slices in serial order and stored in the computer memory. Interpolation was made between a set of the extracted contours by cubic spline functions, then three dimensional models were reconstructed. The three dimensional images were displayed as a wire-frame and/or solid models on the color CRT. Solid model images were obtained as follows. The organ surface constructed from contours was divided into many triangular patches. The intensity of light to each patch was calculated from the direction of incident light, eye position and the normal to the triangular patch. Firstly, this system was applied to the liver phantom. Reconstructed images of the liver phantom were coincident with the actual object. This system also has been applied to human various organs such as brain, lung, liver, etc. The anatomical organ surface was realistically viewed from any direction. The images made us more easily understand the location and configuration of organs in vivo than original CT images. Furthermore, spacial relationship among organs and/or lesions was clearly obtained by superimposition of wire-frame and/or different colored solid models. Therefore, it is expected that this system is clinically useful for evaluating the patho-morphological changes in broad perspective. (author)

  10. 256-Slice coronary computed tomographic angiography in patients with atrial fibrillation: optimal reconstruction phase and image quality

    Energy Technology Data Exchange (ETDEWEB)

    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.)

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

    Science.gov (United States)

    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.

  12. Assessment of Normal Eyeball Protrusion Using Computed Tomographic Imaging and Three-Dimensional Reconstruction in Korean Adults.

    Science.gov (United States)

    Shin, Kang-Jae; Gil, Young-Chun; Lee, Shin-Hyo; Kim, Jeong-Nam; Yoo, Ja-Young; Kim, Soon-Heum; Choi, Hyun-Gon; Shin, Hyun Jin; Koh, Ki-Seok; Song, Wu-Chul

    2017-01-01

    The aim of the present study was to assess normal eyeball protrusion from the orbital rim using two- and three-dimensional images and demonstrate the better suitability of CT images for assessment of exophthalmos. The facial computed tomographic (CT) images of Korean adults were acquired in sagittal and transverse views. The CT images were used in reconstructing three-dimensional volume of faces using computer software. The protrusion distances from orbital rims and the diameters of eyeballs were measured in the two views of the CT image and three-dimensional volume of the face. Relative exophthalmometry was calculated by the difference in protrusion distance between the right and left sides. The eyeball protrusion was 4.9 and 12.5 mm in sagittal and transverse views, respectively. The protrusion distances were 2.9 mm in the three-dimensional volume of face. There were no significant differences between right and left sides in the degree of protrusion, and the difference was within 2 mm in more than 90% of the subjects. The results of the present study will provide reliable criteria for precise diagnosis and postoperative monitoring using CT imaging of diseases such as thyroid-associated ophthalmopathy and orbital tumors.

  13. Computed tomographic reconstruction of beam profiles with a multi-wire chamber

    International Nuclear Information System (INIS)

    Alonso, J.R.; Tobias, C.A.; Chu, W.T.

    1979-03-01

    MEDUSA (MEdical Dose Uniformity SAmpler), a 16 plane multi-wire proportional chamber, has been built to accurately measure beam profiles. The large number of planes allows for reconstruction of highly detailed beam intensity structures by means of Fourier convolution reconstruction techniques. This instrument is being used for verification and tuning of the Bevalac radiotherapy beams, but has potential applications in many beam profile monitoring situations

  14. Emission computed tomograph

    International Nuclear Information System (INIS)

    Hirose, Y.; Kanno, I.; Koga, K.; Miura, S.; Uemura, K.

    1981-01-01

    Emission computed tomograph wherein a pluralty of detectors surround an object to be examined so as to detect x- or gamma radiation emitted by said object. In front of each of said detectors there is provided a collimator which comprises a pair of main plates and a subsidiary plate interposed therebetween. The plates are made of a material capable of blocking penetration of the radiation therethrough and so supported as to be swingable over an angle sufficient to cover the whole of said object. The plates of all the collimators are simultaneously swung to the same side and at the same angular speed thereby to change the direction of incidence of said radiation on each of said detectors

  15. Characteristics of computed tomographic reconstruction noise and their effect on detectability

    International Nuclear Information System (INIS)

    Hanson, K.M.; Boyd, D.P.

    1977-01-01

    The EMI 5005 scanner produces images with noise characteristics similar to those in simulated CT reconstructions. A detectability phantom is described which will provide a means of investigation of the effect on human detection capability of the peculiar correlations present in the noise present in CT scanner images

  16. Distance weighting for improved tomographic reconstructions

    International Nuclear Information System (INIS)

    Koeppe, R.A.; Holden, J.E.

    1984-01-01

    An improved method for the reconstruction of emission computed axial tomography images has been developed. The method is a modification of filtered back-projection, where the back projected values are weighted to reflect the loss of formation, with distance from the camera, which is inherent in gamma camera imaging. This information loss is a result of: loss of spatial resolution with distance, attenuation, and scatter. The weighting scheme can best be described by considering the contributions of any two opposing views to the reconstruction image pixels. The weight applied to the projections of one view is set to equal the relative amount of the original activity that was initially received in that projection, assuming a uniform attenuating medium. This yields a weighting value which is a function of distance into the image with a value of one for pixels ''near the camera'', a value of .5 at the image center, and a value of zero on the opposite side. Tomographic reconstructions produced with this method show improved spatial resolution when compared to conventional 360 0 reconstructions. The improvement is in the tangential direction, where simulations have indicated a FWHM improvement of 1 to 1.5 millimeters. The resolution in the radial direction is essentially the same for both methods. Visual inspection of the reconstructed images show improved resolution and contrast

  17. Bayesian tomographic reconstruction of microsystems

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  18. Comparison among tomographic reconstruction with limited data

    International Nuclear Information System (INIS)

    Oliveira, Eric F.; Dantas, Carlos C.; Vasconcelos, Daniel A.A.; Cadiz, Luis F.; Melo, Silvio B.

    2011-01-01

    Nowadays there is a continuing interest in applying computed tomography (CT) techniques in non-destructive testing and inspection of many industrial products. These applications of CT usually require a differentiated analysis when there are strong limitations in acquiring a sufficiently large amount of projection data. The use of a low number of tomographic data normally degrades the quality of the reconstructed image, highlighting the formation of artifacts and noise. This work investigates the reconstruction methods most commonly used (FBP, ART, SIRT, MART, SMART) and shows the performance of each one in this limited scenario. For this purpose, all methods were implemented and tested with a phantom of uniform density with well-known distribution, with measures of transmission of gamma radiation in a first generation CT scanner. The phantom is a concentric stainless steel tube coupled with a half - cylinder of aluminum. The measurements were made with an highest root mean square error, with the formation of visible artifacts. The artifacts are diminished but still visible in the ART and SIRT techniques, and the best performance was observed with the techniques MART and SMART. The technical superiority of these multiplicative methods is clearly seen in the reconstructed image quality, endorsing their application to situations of limited input data. (author)

  19. Computer tomographic diagnosis of echinococcosis

    Energy Technology Data Exchange (ETDEWEB)

    Haertel, M.; Fretz, C.; Fuchs, W.A.

    1980-08-01

    The computer tomographic appearances and differential diagnosis in 22 patients with echinococcosis are described; of these, twelve were of the cystic and ten of the alveolar type. The computer tomographic appearances are characterised by the presence of daughter cysts (66%) within the sharply demarkated parasitic cyst of water density. In the absence of daughter cysts, a definite aetiological diagnosis cannot be made, although there is a tendency to clasification of the occassionally multiple echinococcus cysts. The computer tomographic appearances of advanced alveolar echinococcosis are characterised by partial collequative necrosis, with clacification around the necrotic areas (90%). The absence of CT evidence of partial necrosis and calsification of the pseudotumour makes it difficult to establish a specific diagnosis. The conclusive and non-invasive character of the procedure and its reproducibility makes computer tomography the method of choice for the diagnosis and follow-up of echinococcosis.

  20. Tomographic image reconstruction using training images

    DEFF Research Database (Denmark)

    Soltani, Sara; Andersen, Martin Skovgaard; Hansen, Per Christian

    2017-01-01

    We describe and examine an algorithm for tomographic image reconstruction where prior knowledge about the solution is available in the form of training images. We first construct a non-negative dictionary based on prototype elements from the training images; this problem is formulated within...

  1. Connections model for tomographic images reconstruction

    International Nuclear Information System (INIS)

    Rodrigues, R.G.S.; Pela, C.A.; Roque, S.F. A.C.

    1998-01-01

    This paper shows an artificial neural network with an adequately topology for tomographic image reconstruction. The associated error function is derived and the learning algorithm is make. The simulated results are presented and demonstrate the existence of a generalized solution for nets with linear activation function. (Author)

  2. Tomographic reconstruction of binary fields

    International Nuclear Information System (INIS)

    Roux, Stéphane; Leclerc, Hugo; Hild, François

    2012-01-01

    A novel algorithm is proposed for reconstructing binary images from their projection along a set of different orientations. Based on a nonlinear transformation of the projection data, classical back-projection procedures can be used iteratively to converge to the sought image. A multiscale implementation allows for a faster convergence. The algorithm is tested on images up to 1 Mb definition, and an error free reconstruction is achieved with a very limited number of projection data, saving a factor of about 100 on the number of projections required for classical reconstruction algorithms.

  3. Longitudinal and transverse digital image reconstruction with a tomographic scanner

    International Nuclear Information System (INIS)

    Pickens, D.R.; Price, R.R.; Erickson, J.J.; Patton, J.A.; Partain, C.L.; Rollo, F.D.

    1981-01-01

    A Siemens Gammasonics PHO/CON-192 Multiplane Imager is interfaced to a digital computer for the purpose of performing tomographic reconstructions from the data collected during a single scan. Data from the two moving gamma cameras as well as camera position information are sent to the computer by an interface designed in the authors' laboratory. Backprojection reconstruction is implemented by the computer. Longitudinal images in whole-body format as well as smaller formats are reconstructed for up to six planes simultaneously from the list mode data. Transverse reconstructions are demonstrated for 201 T1 myocardial scans. Post-reconstruction deconvolution processing to remove the blur artifact (characteristic of focal plane tomography) is applied to a multiplane phantom. Digital data acquisition of data and reconstruction of images are practical, and can extend the usefulness of the machine when compared with the film output (author)

  4. Rational approximations for tomographic reconstructions

    International Nuclear Information System (INIS)

    Reynolds, Matthew; Beylkin, Gregory; Monzón, Lucas

    2013-01-01

    We use optimal rational approximations of projection data collected in x-ray tomography to improve image resolution. Under the assumption that the object of interest is described by functions with jump discontinuities, for each projection we construct its rational approximation with a small (near optimal) number of terms for a given accuracy threshold. This allows us to augment the measured data, i.e., double the number of available samples in each projection or, equivalently, extend (double) the domain of their Fourier transform. We also develop a new, fast, polar coordinate Fourier domain algorithm which uses our nonlinear approximation of projection data in a natural way. Using augmented projections of the Shepp–Logan phantom, we provide a comparison between the new algorithm and the standard filtered back-projection algorithm. We demonstrate that the reconstructed image has improved resolution without additional artifacts near sharp transitions in the image. (paper)

  5. Computed tomographic appearances of cherubism

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, S D; Boccardi, A; Mela, F; Romagnoli, R

    1987-01-01

    The computed tomographic (CT) aspects of six cases of cherubism are described. Through its optimal representation of the lesions, CT enabled certain characteristics of this disease to be substantiated, namely, limitation of the process to the bones of the jaw and primarily superficial development of the mandibular lesions, coupled with an unusual mandibular condylar impairment. Moreover, the composition of this series permitted investigation of the condition in its several stages of progression.

  6. 3D Tomographic Image Reconstruction using CUDA C

    International Nuclear Information System (INIS)

    Dominguez, J. S.; Assis, J. T.; Oliveira, L. F. de

    2011-01-01

    This paper presents the study and implementation of a software for three dimensional reconstruction of images obtained with a tomographic system using the capabilities of Graphic Processing Units(GPU). The reconstruction by filtered back-projection method was developed using the CUDA C, for maximum utilization of the processing capabilities of GPUs to solve computational problems with large computational cost and highly parallelizable. It was discussed the potential of GPUs and shown its advantages to solving this kind of problems. The results in terms of runtime will be compared with non-parallelized implementations and must show a great reduction of processing time. (Author)

  7. Expediting model-based optoacoustic reconstructions with tomographic symmetries

    International Nuclear Information System (INIS)

    Lutzweiler, Christian; Deán-Ben, Xosé Luís; Razansky, Daniel

    2014-01-01

    Purpose: Image quantification in optoacoustic tomography implies the use of accurate forward models of excitation, propagation, and detection of optoacoustic signals while inversions with high spatial resolution usually involve very large matrices, leading to unreasonably long computation times. The development of fast and memory efficient model-based approaches represents then an important challenge to advance on the quantitative and dynamic imaging capabilities of tomographic optoacoustic imaging. Methods: Herein, a method for simplification and acceleration of model-based inversions, relying on inherent symmetries present in common tomographic acquisition geometries, has been introduced. The method is showcased for the case of cylindrical symmetries by using polar image discretization of the time-domain optoacoustic forward model combined with efficient storage and inversion strategies. Results: The suggested methodology is shown to render fast and accurate model-based inversions in both numerical simulations andpost mortem small animal experiments. In case of a full-view detection scheme, the memory requirements are reduced by one order of magnitude while high-resolution reconstructions are achieved at video rate. Conclusions: By considering the rotational symmetry present in many tomographic optoacoustic imaging systems, the proposed methodology allows exploiting the advantages of model-based algorithms with feasible computational requirements and fast reconstruction times, so that its convenience and general applicability in optoacoustic imaging systems with tomographic symmetries is anticipated

  8. A Study on GPU-based Iterative ML-EM Reconstruction Algorithm for Emission Computed Tomographic Imaging Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Woo Seok; Kim, Soo Mee; Park, Min Jae; Lee, Dong Soo; Lee, Jae Sung [Seoul National University, Seoul (Korea, Republic of)

    2009-10-15

    The maximum likelihood-expectation maximization (ML-EM) is the statistical reconstruction algorithm derived from probabilistic model of the emission and detection processes. Although the ML-EM has many advantages in accuracy and utility, the use of the ML-EM is limited due to the computational burden of iterating processing on a CPU (central processing unit). In this study, we developed a parallel computing technique on GPU (graphic processing unit) for ML-EM algorithm. Using Geforce 9800 GTX+ graphic card and CUDA (compute unified device architecture) the projection and backprojection in ML-EM algorithm were parallelized by NVIDIA's technology. The time delay on computations for projection, errors between measured and estimated data and backprojection in an iteration were measured. Total time included the latency in data transmission between RAM and GPU memory. The total computation time of the CPU- and GPU-based ML-EM with 32 iterations were 3.83 and 0.26 sec, respectively. In this case, the computing speed was improved about 15 times on GPU. When the number of iterations increased into 1024, the CPU- and GPU-based computing took totally 18 min and 8 sec, respectively. The improvement was about 135 times and was caused by delay on CPU-based computing after certain iterations. On the other hand, the GPU-based computation provided very small variation on time delay per iteration due to use of shared memory. The GPU-based parallel computation for ML-EM improved significantly the computing speed and stability. The developed GPU-based ML-EM algorithm could be easily modified for some other imaging geometries

  9. A Study on GPU-based Iterative ML-EM Reconstruction Algorithm for Emission Computed Tomographic Imaging Systems

    International Nuclear Information System (INIS)

    Ha, Woo Seok; Kim, Soo Mee; Park, Min Jae; Lee, Dong Soo; Lee, Jae Sung

    2009-01-01

    The maximum likelihood-expectation maximization (ML-EM) is the statistical reconstruction algorithm derived from probabilistic model of the emission and detection processes. Although the ML-EM has many advantages in accuracy and utility, the use of the ML-EM is limited due to the computational burden of iterating processing on a CPU (central processing unit). In this study, we developed a parallel computing technique on GPU (graphic processing unit) for ML-EM algorithm. Using Geforce 9800 GTX+ graphic card and CUDA (compute unified device architecture) the projection and backprojection in ML-EM algorithm were parallelized by NVIDIA's technology. The time delay on computations for projection, errors between measured and estimated data and backprojection in an iteration were measured. Total time included the latency in data transmission between RAM and GPU memory. The total computation time of the CPU- and GPU-based ML-EM with 32 iterations were 3.83 and 0.26 sec, respectively. In this case, the computing speed was improved about 15 times on GPU. When the number of iterations increased into 1024, the CPU- and GPU-based computing took totally 18 min and 8 sec, respectively. The improvement was about 135 times and was caused by delay on CPU-based computing after certain iterations. On the other hand, the GPU-based computation provided very small variation on time delay per iteration due to use of shared memory. The GPU-based parallel computation for ML-EM improved significantly the computing speed and stability. The developed GPU-based ML-EM algorithm could be easily modified for some other imaging geometries

  10. Computer tomographic phantom

    International Nuclear Information System (INIS)

    Lonn, A.H.R.; Jacobsen, D.R.; Zech, D.J.

    1988-01-01

    A reference phantom for computer tomography employs a flexible member with means for urging the flexible member into contact along the curved surface of the lumbar region of a human patient. In one embodiment, the reference phantom is pre-curved in an arc greater than required. Pressure from the weight of a patient laying upon the reference phantom is effective for straightening out the curvature sufficiently to achieve substantial contact along the lumbar region. The curvature of the reference phantom may be additionally distorted by a resilient pad between the resilient phantom and a table for urging it into contact with the lumbar region. In a second embodiment of the invention, a flexible reference phantom is disposed in a slot in the top of a resilient cushion. The resilient cushion and reference phantom may be enclosed in a flexible container. A partially curved reference phantom in a slot in a resilient cushion is also contemplated. (author)

  11. Three-dimensional computed tomographic angiography to predict weight and volume of deep inferior epigastric artery perforator flap for breast reconstruction.

    Science.gov (United States)

    Rosson, Gedge D; Shridharani, Sachin M; Magarakis, Michael; Manahan, Michele A; Stapleton, Sahael M; Gilson, Marta M; Flores, Jaime I; Basdag, Basak; Fishman, Elliot K

    2011-10-01

    Three-dimensional computed tomographic angiography (3D CTA) can be used preoperatively to evaluate the course and caliber of perforating blood vessels for abdominal free-flap breast reconstruction. For postmastectomy breast reconstruction, many women inquire whether the abdominal tissue volume will match that of the breast to be removed. Therefore, our goal was to estimate preoperative volume and weight of the proposed flap and compare them with the actual volume and weight to determine if diagnostic imaging can accurately identify the amount of tissue that could potentially to be harvested. Preoperative 3D CTA was performed in 15 patients, who underwent breast reconstruction using the deep inferior epigastric artery perforator flap. Before each angiogram, stereotactic fiducials were placed on the planned flap outline. The radiologist reviewed each preoperative angiogram to estimate the volume, and thus, weight of the flap. These estimated weights were compared with the actual intraoperative weights. The average estimated weight was 99.7% of the actual weight. The interquartile range (25th to 75th percentile), which represents the "middle half" of the patients, was 91-109%, indicating that half of the patients had an estimated weight within 9% of the actual weight; however, there was a large range (70-133%). 3D CTA with stereotactic fiducials allows surgeons to adequately estimate abdominal flap volume before surgery, potentially giving guidance in the amount of tissue that can be harvested from a patient's lower abdomen. Copyright © 2011 Wiley-Liss, Inc.

  12. Computer tomographic examinations in epilepsy

    International Nuclear Information System (INIS)

    De Villiers, J.F.K.

    1984-01-01

    Epileptic patients that was examined at the Universitas Hospital (Bloemfontein) by means of computerized tomography for the period July 1978 - December 1980, are divided into two groups: a) Patients with general epilepsy of convulsions - 507; b) Patients with vocal or partial epilepsy - 111. The method of examination and the results for both general and vocal epilepsy are discussed. A degenerative state was found in 35% of the positive computer tomographic examinations in general epilepsy and 22% of the positive examinations for vocal epilepsy. The purpose of the article was to explain the circumstances that can be expected when a epileptic patient is examined by means of computerized tomography

  13. Ovarian metastases: Computed tomographic appearances

    International Nuclear Information System (INIS)

    Megibow, A.J.; Hulnick, D.H.; Bosniak, M.A.; Balthazar, E.J.

    1985-01-01

    Computed tomographic scans of 34 patients with ovarian metastases were reviewed to assess the radiographic appearances and to correlate these with the primary neoplasms. Primary neoplasms were located in the colon (20 patients), breast (six), stomach (five), small bowel (one), bladder (one), and Wilms tumor of the kidney (one). The radiographic appearance of the metastatic lesions could be described as predominantly cystic (14 lesions), mixed (12 lesions), or solid (seven lesions). The cystic and mixed lesions tended to be larger in overall diameter than the solid. The metastases from gastric carcinoma appeared solid in four of five cases. The metastases from the other neoplasms had variable appearances simulating primary ovarian carcinoma

  14. Design and applications of Computed Industrial Tomographic Imaging System (CITIS)

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishna, G S; Kumar, Umesh; Datta, S S [Bhabha Atomic Research Centre, Bombay (India). Isotope Div.

    1994-12-31

    This paper highlights the design and development of a prototype Computed Tomographic (CT) imaging system and its software for image reconstruction, simulation and display. It also describes results obtained with several test specimens including Dhruva reactor uranium fuel assembly and possibility of using neutrons as well as high energy x-rays in computed tomography. 5 refs., 4 figs.

  15. A maximum entropy reconstruction technique for tomographic particle image velocimetry

    International Nuclear Information System (INIS)

    Bilsky, A V; Lozhkin, V A; Markovich, D M; Tokarev, M P

    2013-01-01

    This paper studies a novel approach for reducing tomographic PIV computational complexity. The proposed approach is an algebraic reconstruction technique, termed MENT (maximum entropy). This technique computes the three-dimensional light intensity distribution several times faster than SMART, using at least ten times less memory. Additionally, the reconstruction quality remains nearly the same as with SMART. This paper presents the theoretical computation performance comparison for MENT, SMART and MART, followed by validation using synthetic particle images. Both the theoretical assessment and validation of synthetic images demonstrate significant computational time reduction. The data processing accuracy of MENT was compared to that of SMART in a slot jet experiment. A comparison of the average velocity profiles shows a high level of agreement between the results obtained with MENT and those obtained with SMART. (paper)

  16. Jini service to reconstruct tomographic data

    Science.gov (United States)

    Knoll, Peter; Mirzaei, S.; Koriska, K.; Koehn, H.

    2002-06-01

    A number of imaging systems rely on the reconstruction of a 3- dimensional model from its projections through the process of computed tomography (CT). In medical imaging, for example magnetic resonance imaging (MRI), positron emission tomography (PET), and Single Computer Tomography (SPECT) acquire two-dimensional projections of a three dimensional projections of a three dimensional object. In order to calculate the 3-dimensional representation of the object, i.e. its voxel distribution, several reconstruction algorithms have been developed. Currently, mainly two reconstruct use: the filtered back projection(FBP) and iterative methods. Although the quality of iterative reconstructed SPECT slices is better than that of FBP slices, such iterative algorithms are rarely used for clinical routine studies because of their low availability and increased reconstruction time. We used Jini and a self-developed iterative reconstructions algorithm to design and implement a Jini reconstruction service. With this service, the physician selects the patient study from a database and a Jini client automatically discovers the registered Jini reconstruction services in the department's Intranet. After downloading the proxy object the this Jini service, the SPECT acquisition data are reconstructed. The resulting transaxial slices are visualized using a Jini slice viewer, which can be used for various imaging modalities.

  17. Use of a hybrid iterative reconstruction technique to reduce image noise and improve image quality in obese patients undergoing computed tomographic pulmonary angiography.

    Science.gov (United States)

    Kligerman, Seth; Mehta, Dhruv; Farnadesh, Mahmmoudreza; Jeudy, Jean; Olsen, Kathryn; White, Charles

    2013-01-01

    To determine whether an iterative reconstruction (IR) technique (iDose, Philips Healthcare) can reduce image noise and improve image quality in obese patients undergoing computed tomographic pulmonary angiography (CTPA). The study was Health Insurance Portability and Accountability Act compliant and approved by our institutional review board. A total of 33 obese patients (average body mass index: 42.7) underwent CTPA studies following standard departmental protocols. The data were reconstructed with filtered back projection (FBP) and 3 iDose strengths (iDoseL1, iDoseL3, and iDoseL5) for a total of 132 studies. FBP data were collected from 33 controls (average body mass index: 22) undergoing CTPA. Regions of interest were drawn at 6 identical levels in the pulmonary artery (PA), from the main PA to a subsegmental branch, in both the control group and study groups using each algorithm. Noise and attenuation were measured at all PA levels. Three thoracic radiologists graded each study on a scale of 1 (very poor) to 5 (ideal) by 4 categories: image quality, noise, PA enhancement, and "plastic" appearance. Statistical analysis was performed using an unpaired t test, 1-way analysis of variance, and linear weighted κ. Compared with the control group, there was significantly higher noise with FBP, iDoseL1, and iDoseL3 algorithms (Pnoise in the control group and iDoseL5 algorithm in the study group. Analysis within the study group showed a significant and progressive decrease in noise and increase in the contrast-to-noise ratio as the level of IR was increased (Pnoise and PA enhancement with increasing levels of iDose. The use of an IR technique leads to qualitative and quantitative improvements in image noise and image quality in obese patients undergoing CTPA.

  18. Tomographic reconstruction by using FPSIRT (Fast Particle System Iterative Reconstruction Technique)

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Icaro Valgueiro M.; Melo, Silvio de Barros; Dantas, Carlos; Lima, Emerson Alexandre; Silva, Ricardo Martins; Cardoso, Halisson Alberdan C., E-mail: ivmm@cin.ufpe.br, E-mail: sbm@cin.ufpe.br, E-mail: rmas@cin.ufpe.br, E-mail: hacc@cin.ufpe.br, E-mail: ccd@ufpe.br, E-mail: eal@cin.ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2015-07-01

    The PSIRT (Particle System Iterative Reconstruction Technique) is a method of tomographic image reconstruction primarily designed to work with configurations suitable for industrial applications. A particle system is an optimization technique inspired in real physical systems that associates to the reconstructing material a set of particles with certain physical features, subject to a force eld, which can produce movement. The system constantly updates the set of particles by repositioning them in such a way as to approach the equilibrium. The elastic potential along a trajectory is a function of the difference between the attenuation coefficient in the current configuration and the corresponding input data. PSIRT has been successfully used to reconstruct simulated and real objects subject to sets of parallel and fanbeam lines in different angles, representing typical gamma-ray tomographic arrangements. One of PSIRT's limitation was its performance, too slow for real time scenarios. In this work, it is presented a reformulation in PSIRT's computational model, which is able to grant the new algorithm, the FPSIRT - Fast System Iterative Reconstruction Technique, a performance up to 200-time faster than PSIRT's. In this work a comparison of their application to real and simulated data from the HSGT, High Speed Gamma Tomograph, is presented. (author)

  19. Tomographic reconstruction by using FPSIRT (Fast Particle System Iterative Reconstruction Technique)

    International Nuclear Information System (INIS)

    Moreira, Icaro Valgueiro M.; Melo, Silvio de Barros; Dantas, Carlos; Lima, Emerson Alexandre; Silva, Ricardo Martins; Cardoso, Halisson Alberdan C.

    2015-01-01

    The PSIRT (Particle System Iterative Reconstruction Technique) is a method of tomographic image reconstruction primarily designed to work with configurations suitable for industrial applications. A particle system is an optimization technique inspired in real physical systems that associates to the reconstructing material a set of particles with certain physical features, subject to a force eld, which can produce movement. The system constantly updates the set of particles by repositioning them in such a way as to approach the equilibrium. The elastic potential along a trajectory is a function of the difference between the attenuation coefficient in the current configuration and the corresponding input data. PSIRT has been successfully used to reconstruct simulated and real objects subject to sets of parallel and fanbeam lines in different angles, representing typical gamma-ray tomographic arrangements. One of PSIRT's limitation was its performance, too slow for real time scenarios. In this work, it is presented a reformulation in PSIRT's computational model, which is able to grant the new algorithm, the FPSIRT - Fast System Iterative Reconstruction Technique, a performance up to 200-time faster than PSIRT's. In this work a comparison of their application to real and simulated data from the HSGT, High Speed Gamma Tomograph, is presented. (author)

  20. Computed tomographic findings of intracranial gliosis

    International Nuclear Information System (INIS)

    Weisberg, L.

    1981-01-01

    The clinical and computed tomographic (CT) findings in eight patients with pathological evidence of cerebral gliosis are analyzed. CT findings do not permit differentiation of gliosis from other neoplastic and non-neoplastic conditions. (orig.)

  1. Image interface in Java for tomographic reconstruction in nuclear medicine

    International Nuclear Information System (INIS)

    Andrade, M.A.; Silva, A.M. Marques da

    2004-01-01

    The aim of this study is to implement a software for tomographic reconstruction of SPECT data from Nuclear Medicine with a flexible interface design, cross-platform, written in Java. Validation tests were performed based on SPECT simulated data. The results showed that the implemented algorithms and filters agree with the theoretical context. We intend to extend the system by implementing additional tomographic reconstruction techniques and Java threads, in order to provide simultaneously image processing. (author)

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

    Science.gov (United States)

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

    2011-01-01

    Ultrasonography has gained increased utility to diagnose pelvic fractures in horses; however, internal pelvic contours can be difficult to appreciate from external palpable landmarks. We developed three-dimensional (3D) simulations of the pelvic ultrasonographic examination to assist with translation of pelvic contours into two-dimensional (2D) images. Contiguous 1mm transverse computed tomography (CT) images were acquired through an equine femur and hemipelvis using a single slice helical scanner. 3D surface models were created using a DICOM reader and imported into a 3D modeling and animation program. The bone models were combined with a purchased 3D horse model and the skin made translucent to visualize pelvic surface contours. 3D models of ultrasound transducers were made from reference photos, and a thin sector shape was created to depict the ultrasound beam. Ultrasonographic examinations were simulated by moving transducers on the skin surface and rectally to produce images of pelvic structures. Camera angles were manipulated to best illustrate the transducer-beam-bone interface. Fractures were created in multiple configurations. Animations were exported as QuickTime movie files for use in presentations coupled with corresponding ultrasound videoclips. 3D models provide a link between ultrasonographic technique and image generation by depicting the interaction of the transducer, ultrasound beam, and structure of interest. The horse model was important to facilitate understanding of the location of pelvic structures relative to the skin surface. While CT acquisition time was brief, manipulation within the 3D software program was time intensive. Results were worthwhile from an instructional standpoint based on user feedback. © 2011 Veterinary Radiology & Ultrasound.

  3. Computed tomographic findings of intracranial pyogenic abscess

    International Nuclear Information System (INIS)

    Kim, S. J.; Suh, J. H.; Park, C. Y.; Lee, K. C.; Chung, S. S.

    1982-01-01

    The early diagnosis and effective treatment of brain abscess pose a difficult clinical problem. With the advent of computed tomography, however, it appears that mortality due to intracranial abscess has significantly diminished. 54 cases of intracranial pyogenic abscess are presented. Etiologic factors and computed tomographic findings are analyzed and following result are obtained. 1. The common etiologic factors are otitis media, post operation, and head trauma, in order of frequency. 2. The most common initial computed tomographic findings of brain abscess is ring contrast enhancement with surrounding brain edema. 3. The most characteristic computed tomographic finding of ring contrast enhancement is smooth thin walled ring contrast enhancement. 4. Most of thick irregular ring contrast enhancement are abscess associated with cyanotic heart disease or poor operation. 5. The most common findings of epidural and subdural empyema is crescentic radiolucent area with thin wall contrast enhancement without surrounding brain edema in convexity of brain

  4. Design and applications of Computed Industrial Tomographic Imaging System (CITIS)

    International Nuclear Information System (INIS)

    Ramakrishna, G.S.; Umesh Kumar; Datta, S.S.; Rao, S.M.

    1996-01-01

    Computed tomographic imaging is an advanced technique for nondestructive testing (NDT) and examination. For the first time in India a computed aided tomography system has been indigenously developed in BARC for testing industrial components and was successfully demonstrated. The system in addition to Computed Tomography (CT) can also perform Digital Radiography (DR) to serve as a powerful tool for NDT applications. It has wider applications in the fields of nuclear, space and allied fields. The authors have developed a computed industrial tomographic imaging system with Cesium 137 gamma radiation source for nondestructive examination of engineering and industrial specimens. This presentation highlights the design and development of a prototype system and its software for image reconstruction, simulation and display. The paper also describes results obtained with several tests specimens, current development and possibility of using neutrons as well as high energy x-rays in computed tomography. (author)

  5. Computed tomographic appearances of sternocostoclavicular hyperostosis

    Energy Technology Data Exchange (ETDEWEB)

    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).

  6. Computed tomographic appearances of sternocostoclavicular hyperostosis

    International Nuclear Information System (INIS)

    Chigira, Masaki; Shimizu, Toru

    1989-01-01

    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)

  7. Case Report: Unusual computed tomographic features of ...

    African Journals Online (AJOL)

    A case report of a 57-year old woman who presented with signs and symptoms of intracranial mass. Computed tomographic (CT) and clinical features were unusual and suggestive of a parasaggital Meningioma. However an accurate diagnosis of a tuberculoma was made at surgery and histopathological examination.

  8. Reconstruction of tomographic image from x-ray projections of a few views

    International Nuclear Information System (INIS)

    Kobayashi, Fujio; Yamaguchi, Shoichiro

    1982-01-01

    Computer tomographs have progressed rapidly, and in the latest high performance types, the photographing time has been shortened to less than 5 sec, but the clear images of hearts have not yet been obtained. The X-ray tomographs used so far irradiate X-ray from many directions and measure the projected data, but by limiting projection direction to a small number, it was planned to shorter the X-ray photographing time and to reduce X-ray exposure as the objective of this study. In this paper, a method is proposed, by which tomographic images are reconstructed from projected data in a small number of direction by generalized inverse matrix penalty method. This method is the calculation method newly devised by the authors for this purpose. It is a kind of the nonlinear planning method added with the restrictive condition using a generalized inverse matrix, and it is characterized by the simple calculation procedure and rapid convergence. Moreover, the effect on reconstructed images when errors are included in projected data was examined. Also, the simple computer simulation to reconstruct tomographic images using the projected data in four directions was performed, and the usefulness of this method was confirmed. It contributes to the development of superhigh speed tomographs in future. (Kako, I.)

  9. Tomographic reconstruction of neopterous carboniferous insect nymphs.

    Directory of Open Access Journals (Sweden)

    Russell Garwood

    Full Text Available Two new polyneopteran insect nymphs from the Montceau-les-Mines Lagerstätte of France are presented. Both are preserved in three dimensions, and are imaged with the aid of X-ray micro-tomography, allowing their morphology to be recovered in unprecedented detail. One-Anebos phrixos gen. et sp. nov.-is of uncertain affinities, and preserves portions of the antennae and eyes, coupled with a heavily spined habitus. The other is a roachoid with long antennae and chewing mouthparts very similar in form to the most generalized mandibulate mouthparts of extant orthopteroid insects. Computer reconstructions reveal limbs in both specimens, allowing identification of the segments and annulation in the tarsus, while poorly developed thoracic wing pads suggest both are young instars. This work describes the morphologically best-known Palaeozoic insect nymphs, allowing a better understanding of the juveniles' palaeobiology and palaeoecology. We also consider the validity of evidence from Palaeozoic juvenile insects in wing origin theories. The study of juvenile Palaeozoic insects is currently a neglected field, yet these fossils provide direct evidence on the evolution of insect development. It is hoped this study will stimulate a renewed interest in such work.

  10. Tomographic image reconstruction using Artificial Neural Networks

    International Nuclear Information System (INIS)

    Paschalis, P.; Giokaris, N.D.; Karabarbounis, A.; Loudos, G.K.; Maintas, D.; Papanicolas, C.N.; Spanoudaki, V.; Tsoumpas, Ch.; Stiliaris, E.

    2004-01-01

    A new image reconstruction technique based on the usage of an Artificial Neural Network (ANN) is presented. The most crucial factor in designing such a reconstruction system is the network architecture and the number of the input projections needed to reconstruct the image. Although the training phase requires a large amount of input samples and a considerable CPU time, the trained network is characterized by simplicity and quick response. The performance of this ANN is tested using several image patterns. It is intended to be used together with a phantom rotating table and the γ-camera of IASA for SPECT image reconstruction

  11. Development of the Shimadzu computed tomographic scanner SCT-200N

    International Nuclear Information System (INIS)

    Ishihara, Hiroshi; Yamaoka, Nobuyuki; Saito, Masahiro

    1982-01-01

    The Shimadzu Computed Tomographic Scanner SCT-200N has been developed as an ideal CT scanner for diagnosing the head and spine. Due to the large aperture, moderate scan time and the Zoom Scan Mode, any part of the body can be scanned. High quality image can be obtained by adopting the precisely stabilized X-ray unit and densely packed array of 64-detectors. As for its operation, capability of computed radiography (CR) prior to patient positioning and real time reconstruction ensure efficient patient through-put. Details of the SCT-200N are described in this paper. (author)

  12. The optimal monochromatic spectral computed tomographic imaging plus adaptive statistical iterative reconstruction algorithm can improve the superior mesenteric vessel image quality

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Xiao-Ping; Zuo, Zi-Wei; Xu, Ying-Jin; Wang, Jia-Ning [CT/MRI room, Affiliated Hospital of Hebei University, Baoding, Hebei, 071000 (China); Liu, Huai-Jun, E-mail: hebeiliu@outlook.com [Department of Medical Imaging, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, 050000 (China); Liang, Guang-Lu [CT/MRI room, Affiliated Hospital of Hebei University, Baoding, Hebei, 071000 (China); Gao, Bu-Lang, E-mail: browngao@163.com [Department of Medical Research, Shijiazhuang First Hospital, Shijiazhuang, Hebei, 050011 (China)

    2017-04-15

    Objective: To investigate the effect of the optimal monochromatic spectral computed tomography (CT) plus adaptive statistical iterative reconstruction on the improvement of the image quality of the superior mesenteric artery and vein. Materials and methods: The gemstone spectral CT angiographic data of 25 patients were reconstructed in the following three groups: 70 KeV, the optimal monochromatic imaging, and the optimal monochromatic plus 40%iterative reconstruction mode. The CT value, image noises (IN), background CT value and noises, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and image scores of the vessels and surrounding tissues were analyzed. Results: In the 70 KeV, the optimal monochromatic and the optimal monochromatic images plus 40% iterative reconstruction group, the mean scores of image quality were 3.86, 4.24 and 4.25 for the superior mesenteric artery and 3.46, 3.78 and 3.81 for the superior mesenteric vein, respectively. The image quality scores for the optimal monochromatic and the optimal monochromatic plus 40% iterative reconstruction groups were significantly greater than for the 70 KeV group (P < 0.05). The vascular CT value, image noise, background noise, CNR and SNR were significantly (P < 0.001) greater in the optimal monochromatic and the optimal monochromatic images plus 40% iterative reconstruction group than in the 70 KeV group. The optimal monochromatic plus 40% iterative reconstruction group had significantly (P < 0.05) lower image and background noise but higher CNR and SNR than the other two groups. Conclusion: The optimal monochromatic imaging combined with 40% iterative reconstruction using low-contrast agent dosage and low injection rate can significantly improve the image quality of the superior mesenteric artery and vein.

  13. Industrial dynamic tomographic reconstruction; Reconstrucao tomografica dinamica industrial

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Eric Ferreira de

    2016-07-01

    The state of the art methods applied to industrial processes is currently based on the principles of classical tomographic reconstructions developed for tomographic patterns of static distributions, or is limited to cases of low variability of the density distribution function of the tomographed object. Noise and motion artifacts are the main problems caused by a mismatch in the data from views acquired in different instants. All of these add to the known fact that using a limited amount of data can result in the presence of noise, artifacts and some inconsistencies with the distribution under study. One of the objectives of the present work is to discuss the difficulties that arise from implementing reconstruction algorithms in dynamic tomography that were originally developed for static distributions. Another objective is to propose solutions that aim at reducing a temporal type of information loss caused by employing regular acquisition systems to dynamic processes. With respect to dynamic image reconstruction it was conducted a comparison between different static reconstruction methods, like MART and FBP, when used for dynamic scenarios. This comparison was based on a MCNPx simulation as well as an analytical setup of an aluminum cylinder that moves along the section of a riser during the process of acquisition, and also based on cross section images from CFD techniques. As for the adaptation of current tomographic acquisition systems for dynamic processes, this work established a sequence of tomographic views in a just-in-time fashion for visualization purposes, a form of visually disposing density information as soon as it becomes amenable to image reconstruction. A third contribution was to take advantage of the triple color channel necessary to display colored images in most displays, so that, by appropriately scaling the acquired values of each view in the linear system of the reconstruction, it was possible to imprint a temporal trace into the regularly

  14. Tomographic Image Reconstruction Using Training Images with Matrix and Tensor Formulations

    DEFF Research Database (Denmark)

    Soltani, Sara

    the image resolution compared to a classical reconstruction method such as Filtered Back Projection (FBP). Some priors for the tomographic reconstruction take the form of cross-section images of similar objects, providing a set of the so-called training images, that hold the key to the structural......Reducing X-ray exposure while maintaining the image quality is a major challenge in computed tomography (CT); since the imperfect data produced from the few view and/or low intensity projections results in low-quality images that are suffering from severe artifacts when using conventional...... information about the solution. The training images must be reliable and application-specific. This PhD project aims at providing a mathematical and computational framework for the use of training sets as non-parametric priors for the solution in tomographic image reconstruction. Through an unsupervised...

  15. The computed tomographic appearances of cherubism

    International Nuclear Information System (INIS)

    Bianchi, S.D.; Boccardi, A.; Mela, F.; Romagnoli, R.

    1987-01-01

    The computed tomographic (CT) aspects of six cases of cherubism are described. Through its optimal representation of the lesions, CT enabled certain characteristics of this disease to be substantiated, namely, limitation of the process to the bones of the jaw and primarily superficial development of the mandibular lesions, coupled with an unusual mandibular condylar impairment. Moreover, the composition of this series permitted investigation of the condition in its several stages of progression. (orig.)

  16. Computed tomographic appearance of mucormycosis

    International Nuclear Information System (INIS)

    Vogl, T.J.; Hinrichs, T.; Jacobi, V.; Boehme, A.; Hoelzer, D.

    2000-01-01

    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.) [de

  17. Tomographic reconstruction with B-splines surfaces

    International Nuclear Information System (INIS)

    Oliveira, Eric F.; Dantas, Carlos C.; Melo, Silvio B.; Mota, Icaro V.; Lira, Mailson

    2011-01-01

    Algebraic reconstruction techniques when applied to a limited number of data usually suffer from noise caused by the process of correction or by inconsistencies in the data coming from the stochastic process of radioactive emission and oscillation equipment. The post - processing of the reconstructed image with the application of filters can be done to mitigate the presence of noise. In general these processes also attenuate the discontinuities present in edges that distinguish objects or artifacts, causing excessive blurring in the reconstructed image. This paper proposes a built-in noise reduction at the same time that it ensures adequate smoothness level in the reconstructed surface, representing the unknowns as linear combinations of elements of a piecewise polynomial basis, i.e. a B-splines basis. For that, the algebraic technique ART is modified to accommodate the first, second and third degree bases, ensuring C 0 , C 1 and C 2 smoothness levels, respectively. For comparisons, three methodologies are applied: ART, ART post-processed with regular B-splines filters (ART*) and the proposed method with the built-in B-splines filter (BsART). Simulations with input data produced from common mathematical phantoms were conducted. For the phantoms used the BsART method consistently presented the smallest errors, among the three methods. This study has shown the superiority of the change made to embed the filter in the ART when compared to the post-filtered ART. (author)

  18. Rapid tomographic reconstruction based on machine learning for time-resolved combustion diagnostics

    Science.gov (United States)

    Yu, Tao; Cai, Weiwei; Liu, Yingzheng

    2018-04-01

    Optical tomography has attracted surged research efforts recently due to the progress in both the imaging concepts and the sensor and laser technologies. The high spatial and temporal resolutions achievable by these methods provide unprecedented opportunity for diagnosis of complicated turbulent combustion. However, due to the high data throughput and the inefficiency of the prevailing iterative methods, the tomographic reconstructions which are typically conducted off-line are computationally formidable. In this work, we propose an efficient inversion method based on a machine learning algorithm, which can extract useful information from the previous reconstructions and build efficient neural networks to serve as a surrogate model to rapidly predict the reconstructions. Extreme learning machine is cited here as an example for demonstrative purpose simply due to its ease of implementation, fast learning speed, and good generalization performance. Extensive numerical studies were performed, and the results show that the new method can dramatically reduce the computational time compared with the classical iterative methods. This technique is expected to be an alternative to existing methods when sufficient training data are available. Although this work is discussed under the context of tomographic absorption spectroscopy, we expect it to be useful also to other high speed tomographic modalities such as volumetric laser-induced fluorescence and tomographic laser-induced incandescence which have been demonstrated for combustion diagnostics.

  19. Computer tomographic findings in alcoholism

    Energy Technology Data Exchange (ETDEWEB)

    Agnoli, A.L.; Tzavaras, N.; Reisig, L. (Giessen Univ. (Germany, F.R.). Abt. Neuroradiologie)

    1980-05-01

    The normal variations in the size of the ventricular systems was determined on technically satisfactory computer tomograms in 275 patients who were psychologically and neurologically normal. Ages range from one to 80 years and the data classified in decades. A physiological increase in the width of the ventricular system was found after the 50sup(t)sup(h) year. The normal patients, who acted as a control group, were compared with 65 alcoholics. A significant increase in size (simple variance) was found in alcoholics after the fourth decade, as compared with normals. Correlation between the width of the ventricular system and cerebral function, and between liver damage and the ventricular system could not be established.

  20. A distributed multi-GPU system for high speed electron microscopic tomographic reconstruction

    International Nuclear Information System (INIS)

    Zheng, Shawn Q.; Branlund, Eric; Kesthelyi, Bettina; Braunfeld, Michael B.; Cheng, Yifan; Sedat, John W.; Agard, David A.

    2011-01-01

    Full resolution electron microscopic tomographic (EMT) reconstruction of large-scale tilt series requires significant computing power. The desire to perform multiple cycles of iterative reconstruction and realignment dramatically increases the pressing need to improve reconstruction performance. This has motivated us to develop a distributed multi-GPU (graphics processing unit) system to provide the required computing power for rapid constrained, iterative reconstructions of very large three-dimensional (3D) volumes. The participating GPUs reconstruct segments of the volume in parallel, and subsequently, the segments are assembled to form the complete 3D volume. Owing to its power and versatility, the CUDA (NVIDIA, USA) platform was selected for GPU implementation of the EMT reconstruction. For a system containing 10 GPUs provided by 5 GTX295 cards, 10 cycles of SIRT reconstruction for a tomogram of 4096 2 x512 voxels from an input tilt series containing 122 projection images of 4096 2 pixels (single precision float) takes a total of 1845 s of which 1032 s are for computation with the remainder being the system overhead. The same system takes only 39 s total to reconstruct 1024 2 x256 voxels from 122 1024 2 pixel projections. While the system overhead is non-trivial, performance analysis indicates that adding extra GPUs to the system would lead to steadily enhanced overall performance. Therefore, this system can be easily expanded to generate superior computing power for very large tomographic reconstructions and especially to empower iterative cycles of reconstruction and realignment. -- Highlights: → A distributed multi-GPU system has been developed for electron microscopic tomography (EMT). → This system allows for rapid constrained, iterative reconstruction of very large volumes. → This system can be easily expanded to generate superior computing power for large-scale iterative EMT realignment.

  1. A distributed multi-GPU system for high speed electron microscopic tomographic reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Shawn Q.; Branlund, Eric; Kesthelyi, Bettina; Braunfeld, Michael B.; Cheng, Yifan; Sedat, John W. [The Howard Hughes Medical Institute and the W.M. Keck Advanced Microscopy Laboratory, Department of Biochemistry and Biophysics, University of California, San Francisco, 600, 16th Street, Room S412D, CA 94158-2517 (United States); Agard, David A., E-mail: agard@msg.ucsf.edu [The Howard Hughes Medical Institute and the W.M. Keck Advanced Microscopy Laboratory, Department of Biochemistry and Biophysics, University of California, San Francisco, 600, 16th Street, Room S412D, CA 94158-2517 (United States)

    2011-07-15

    Full resolution electron microscopic tomographic (EMT) reconstruction of large-scale tilt series requires significant computing power. The desire to perform multiple cycles of iterative reconstruction and realignment dramatically increases the pressing need to improve reconstruction performance. This has motivated us to develop a distributed multi-GPU (graphics processing unit) system to provide the required computing power for rapid constrained, iterative reconstructions of very large three-dimensional (3D) volumes. The participating GPUs reconstruct segments of the volume in parallel, and subsequently, the segments are assembled to form the complete 3D volume. Owing to its power and versatility, the CUDA (NVIDIA, USA) platform was selected for GPU implementation of the EMT reconstruction. For a system containing 10 GPUs provided by 5 GTX295 cards, 10 cycles of SIRT reconstruction for a tomogram of 4096{sup 2}x512 voxels from an input tilt series containing 122 projection images of 4096{sup 2} pixels (single precision float) takes a total of 1845 s of which 1032 s are for computation with the remainder being the system overhead. The same system takes only 39 s total to reconstruct 1024{sup 2}x256 voxels from 122 1024{sup 2} pixel projections. While the system overhead is non-trivial, performance analysis indicates that adding extra GPUs to the system would lead to steadily enhanced overall performance. Therefore, this system can be easily expanded to generate superior computing power for very large tomographic reconstructions and especially to empower iterative cycles of reconstruction and realignment. -- Highlights: {yields} A distributed multi-GPU system has been developed for electron microscopic tomography (EMT). {yields} This system allows for rapid constrained, iterative reconstruction of very large volumes. {yields} This system can be easily expanded to generate superior computing power for large-scale iterative EMT realignment.

  2. Computed tomographic findings of traumatic intracranial lesions

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Seong Wook; Kim, Il Young; Lee, Byung Ho; Kim, Ki Jeoung; Yoon, Il Gyu [Soonchunhyang University College of Medicine, Seoul (Korea, Republic of)

    1985-10-15

    Traumatic intracranial lesion has been one of the most frequent and serious problem in neurosurgical pathology. Computed tomography made it possible to get prompt diagnosis and surgical intervention of intracranial lesions by its safety, fastness and accuracy. Computed tomographic scan was carried out on 1309 cases at Soonchunhyang Chunan Hospital for 15 months from October 1983 to December 1984. We have reviewed the computed tomographic scans of 264 patients which showed traumatic intracranial lesion. The result were as follows: 1. Head trauma was the most frequent diagnosed disease using computed tomographic scans (57.8%) and among 264 cases the most frequent mode of injury was traffic accident (73.9%). 2. Skull fracture was accompanied in frequency of 69.7% and it was detected in CT in 38.6%: depression fracture was more easily detected in 81%. 3. Conutercoup lesion (9.5%) was usually accompanied with temporal and occipital fracture, and it appeared in lower incidence among pediatric group. 4. Intracranial lesions of all 264 cases were generalized cerebral swelling (24.6%), subdural hematoma (22.3%), epidural hematoma (20.8%), intracerebral hematoma (6.1%), and subarachnoid hemorrhage (3.0%). 5. The shape of hematoma was usually biconvex (92.7%) in acute epidural hematoma and cresentic (100%) in acute subdural hematoma, but the most chronic the case became, they showed planoconvex and bicconvex shapes. 6. Extra-axial hematoma was getting decreased in density as time gone by. 7. Hematoma density was not in direct proportion to serum hemoglobin level as single factor.

  3. Computed tomographic findings of traumatic intracranial lesions

    International Nuclear Information System (INIS)

    Jeong, Seong Wook; Kim, Il Young; Lee, Byung Ho; Kim, Ki Jeoung; Yoon, Il Gyu

    1985-01-01

    Traumatic intracranial lesion has been one of the most frequent and serious problem in neurosurgical pathology. Computed tomography made it possible to get prompt diagnosis and surgical intervention of intracranial lesions by its safety, fastness and accuracy. Computed tomographic scan was carried out on 1309 cases at Soonchunhyang Chunan Hospital for 15 months from October 1983 to December 1984. We have reviewed the computed tomographic scans of 264 patients which showed traumatic intracranial lesion. The result were as follows: 1. Head trauma was the most frequent diagnosed disease using computed tomographic scans (57.8%) and among 264 cases the most frequent mode of injury was traffic accident (73.9%). 2. Skull fracture was accompanied in frequency of 69.7% and it was detected in CT in 38.6%: depression fracture was more easily detected in 81%. 3. Conutercoup lesion (9.5%) was usually accompanied with temporal and occipital fracture, and it appeared in lower incidence among pediatric group. 4. Intracranial lesions of all 264 cases were generalized cerebral swelling (24.6%), subdural hematoma (22.3%), epidural hematoma (20.8%), intracerebral hematoma (6.1%), and subarachnoid hemorrhage (3.0%). 5. The shape of hematoma was usually biconvex (92.7%) in acute epidural hematoma and cresentic (100%) in acute subdural hematoma, but the most chronic the case became, they showed planoconvex and bicconvex shapes. 6. Extra-axial hematoma was getting decreased in density as time gone by. 7. Hematoma density was not in direct proportion to serum hemoglobin level as single factor

  4. DG TOMO: A new method for tomographic reconstruction

    International Nuclear Information System (INIS)

    Freitas, D. de; Feschet, F.; Cachin, F.; Geissler, B.; Bapt, A.; Karidioula, I.; Martin, C.; Kelly, A.; Mestas, D.; Gerard, Y.; Reveilles, J.P.; Maublant, J.

    2006-01-01

    Aim: FBP and OSEM are the most popular tomographic reconstruction methods in scintigraphy. FBP is a simple method but artifacts of reconstruction are generated which corrections induce degradation of the spatial resolution. OSEM takes account of statistical fluctuations but noise strongly increases after a certain number of iterations. We compare a new method of tomographic reconstruction based on discrete geometry (DG TOMO) to FBP and OSEM. Materials and methods: Acquisitions were performed on a three-head gamma-camera (Philips) with a NEMA Phantom containing six spheres of sizes from 10 to 37 mm inner diameter, filled with around 325 MBq/l of technetium-99 m. The spheres were positioned in water containing 3 MBq/l of technetium-99 m. Acquisitions were realized during a 180 o -rotation around the phantom by 25-s steps. DG TOMO has been developed in our laboratory in order to minimize the number of projections at acquisition. Two tomographic reconstructions utilizing 32 and 16 projections with FBP, OSEM and DG TOMO were performed and transverse slices were compared. Results: FBP with 32 projections detects only the activity in the three largest spheres (diameter ≥22 mm). With 16 projections, the star effect is predominant and the contrast of the third sphere is very low. OSEM with 32 projections provides a better image but the three smallest spheres (diameter ≤17 mm) are difficult to distinguish. With 16 projections, the three smaller spheres are not detectable. The results of DG TOMO are similar to OSEM. Conclusion: Since the parameters of DG TOMO can be further optimized, this method appears as a promising alternative for tomoscintigraphy reconstruction

  5. Computer tomographic investigation of ancient Egyptian mummies

    International Nuclear Information System (INIS)

    Huebner, K.H.; Pahl, W.M.; Tuebingen Univ.

    1981-01-01

    Radiological and computer tomographic examinations of Egyptian mummies have been carried out at the Institute of Anthropology and Human Genetics from 1975 to 1978. These have demonstrated the value of CT in medical archaeology. It enables one to study the soft tissues, the skin (if bandaged), the muscles and any organs retained in situ for magical or religious reason. Measurements of attenuation values indicate the materials which were used for mummifying the skin and organs. Characteristic examples are described and the early results of these examinations are discussed. (orig.) [de

  6. Computer tomographic investigation of ancient Egyptian mummies

    Energy Technology Data Exchange (ETDEWEB)

    Huebner, K H; Pahl, W M

    1981-08-01

    Radiological and computer tomographic examinations of Egyptian mummies have been carried out at the Institute of Anthropology and Human Genetics from 1975 to 1978. These have demonstrated the value of CT in medical archaeology. It enables one to study the soft tissues, the skin (if bandaged), the muscles and any organs retained in situ for magical or religious reason. Measurements of attenuation values indicate the materials which were used for mummifying the skin and organs. Characteristic examples are described and the early results of these examinations are discussed.

  7. Computed tomographic study in children with microcephaly

    International Nuclear Information System (INIS)

    Ito, Masatoshi; Okuno, Takehiko; Mikawa, Haruki

    1989-01-01

    Computed tomographic (CT) brain scanning was performed on fifty-eight infants and children with microcephaly. CT scans were useful for detecting unsuspected brain lesions and for diagnosing underlying diseases. The head size did not correlate with the CT findings, the degree of mental retardation, or the existence of motor disturbance or epilepsy. On the other hand, the CT findings were correlated with the degree of mental retardation, and the existence of motor disturbance or epilepsy. CT scans were useful for determining the prognosis of the microcephaly. (author)

  8. Fast Tomographic Reconstruction From Limited Data Using Artificial Neural Networks

    NARCIS (Netherlands)

    D.M. Pelt (Daniël); K.J. Batenburg (Joost)

    2013-01-01

    htmlabstractImage reconstruction from a small number of projections is a challenging problem in tomography. Advanced algorithms that incorporate prior knowledge can sometimes produce accurate reconstructions, but they typically require long computation times. Furthermore, the required prior

  9. A distributed multi-GPU system for high speed electron microscopic tomographic reconstruction.

    Science.gov (United States)

    Zheng, Shawn Q; Branlund, Eric; Kesthelyi, Bettina; Braunfeld, Michael B; Cheng, Yifan; Sedat, John W; Agard, David A

    2011-07-01

    Full resolution electron microscopic tomographic (EMT) reconstruction of large-scale tilt series requires significant computing power. The desire to perform multiple cycles of iterative reconstruction and realignment dramatically increases the pressing need to improve reconstruction performance. This has motivated us to develop a distributed multi-GPU (graphics processing unit) system to provide the required computing power for rapid constrained, iterative reconstructions of very large three-dimensional (3D) volumes. The participating GPUs reconstruct segments of the volume in parallel, and subsequently, the segments are assembled to form the complete 3D volume. Owing to its power and versatility, the CUDA (NVIDIA, USA) platform was selected for GPU implementation of the EMT reconstruction. For a system containing 10 GPUs provided by 5 GTX295 cards, 10 cycles of SIRT reconstruction for a tomogram of 4096(2) × 512 voxels from an input tilt series containing 122 projection images of 4096(2) pixels (single precision float) takes a total of 1845 s of which 1032 s are for computation with the remainder being the system overhead. The same system takes only 39 s total to reconstruct 1024(2) × 256 voxels from 122 1024(2) pixel projections. While the system overhead is non-trivial, performance analysis indicates that adding extra GPUs to the system would lead to steadily enhanced overall performance. Therefore, this system can be easily expanded to generate superior computing power for very large tomographic reconstructions and especially to empower iterative cycles of reconstruction and realignment. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Terahertz Imaging for Biomedical Applications Pattern Recognition and Tomographic Reconstruction

    CERN Document Server

    Yin, Xiaoxia; Abbott, Derek

    2012-01-01

    Terahertz Imaging for Biomedical Applications: Pattern Recognition and Tomographic Reconstruction presents the necessary algorithms needed to assist screening, diagnosis, and treatment, and these algorithms will play a critical role in the accurate detection of abnormalities present in biomedical imaging. Terahertz biomedical imaging has become an area of interest due to its ability to simultaneously acquire both image and spectral information. Terahertz imaging systems are being commercialized with an increasing number of trials performed in a biomedical setting. Terahertz tomographic imaging and detection technology contributes to the ability to identify opaque objects with clear boundaries,and would be useful to both in vivo and ex vivo environments. This book also: Introduces terahertz radiation techniques and provides a number of topical examples of signal and image processing, as well as machine learning Presents the most recent developments in an emerging field, terahertz radiation Utilizes new methods...

  11. Pipelining Computational Stages of the Tomographic Reconstructor for Multi-Object Adaptive Optics on a Multi-GPU System

    KAUST Repository

    Charara, Ali; Ltaief, Hatem; Gratadour, Damien; Keyes, David E.; Sevin, Arnaud; Abdelfattah, Ahmad; Gendron, Eric; Morel, Carine; Vidal, Fabrice

    2014-01-01

    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

  12. Low-dose computed tomographic imaging in orbital trauma

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, A.; Whitehouse, R.W. (Manchester Univ. (United Kingdom). Dept. of Diagnostic Radiology)

    1993-08-01

    The authors review findings in 75 computed tomographic (CT) examinations of 66 patients with orbital trauma who were imaged using a low-radiation-dose CT technique. Imaging was performed using a dynamic scan mode and exposure factors of 120 kVp and 80 mAs resulting in a skin dose of 11 mGy with an effective dose-equivalent of 0.22 mSv. Image quality was diagnostic in all cases and excellent in 73 examinations. Soft-tissue abnormalities within the orbit including muscle adhesions were well demonstrated both on primary axial and reconstructed multiplanar images. The benefits of multiplanar reconstructions are stressed and the contribution of soft-tissue injuries to symptomatic diplopia examined. (author).

  13. New method to analyze internal disruptions with tomographic reconstructions

    Energy Technology Data Exchange (ETDEWEB)

    Tanzi, C.P. [EURATOM-FOM Association, FOM-Instituut voor Plasmafysica Rijnhuizen, P.O. BOX 1207, 3430 BE Nieuwegein (The Netherlands); de Blank, H.J. [Max-Planck-Institut fuer Plasmaphysik, EURATOM-IPP Association, 85740 Garching (Germany)

    1997-03-01

    Sawtooth crashes have been investigated on the Rijnhuizen Tokamak Project (RTP) [N. J. Lopes Cardozo {ital et al.}, {ital Proceedings of the 14th International Conference on Plasma Physics and Controlled Nuclear Fusion Research}, W{umlt u}rzburg, 1992 (International Atomic Energy Agency, Vienna, 1993), Vol. 1, p. 271]. Internal disruptions in tokamak plasmas often exhibit an m=1 poloidal mode structure prior to the collapse which can be clearly identified by means of multicamera soft x-ray diagnostics. In this paper tomographic reconstructions of such m=1 modes are analyzed with a new method, based on magnetohydrodynamic (MHD) invariants computed from the two-dimensional emissivity profiles, which quantifies the amount of profile flattening not only after the crash but also during the precursor oscillations. The results are interpreted by comparing them with two models which simulate the measurements of the m=1 redistribution of soft x-ray emissivity prior to the sawtooth crash. One model is based on the magnetic reconnection model of Kadomtsev. The other involves ideal MHD motion only. In cases where differences in magnetic topology between the two models cannot be seen in the tomograms, the analysis of profile flattening has an advantage. The analysis shows that in RTP the clearly observed m=1 displacement of some sawteeth requires the presence of convective ideal MHD motion, whereas other precursors are consistent with magnetic reconnection of up to 75{percent} of the magnetic flux within the q=1 surface. The possibility of ideal interchange combined with enhanced cross-field transport is not excluded. {copyright} {ital 1997 American Institute of Physics.}

  14. New method to analyze internal disruptions with tomographic reconstructions

    International Nuclear Information System (INIS)

    Tanzi, C.P.; de Blank, H.J.

    1997-01-01

    Sawtooth crashes have been investigated on the Rijnhuizen Tokamak Project (RTP) [N. J. Lopes Cardozo et al., Proceedings of the 14th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Wuerzburg, 1992 (International Atomic Energy Agency, Vienna, 1993), Vol. 1, p. 271]. Internal disruptions in tokamak plasmas often exhibit an m=1 poloidal mode structure prior to the collapse which can be clearly identified by means of multicamera soft x-ray diagnostics. In this paper tomographic reconstructions of such m=1 modes are analyzed with a new method, based on magnetohydrodynamic (MHD) invariants computed from the two-dimensional emissivity profiles, which quantifies the amount of profile flattening not only after the crash but also during the precursor oscillations. The results are interpreted by comparing them with two models which simulate the measurements of the m=1 redistribution of soft x-ray emissivity prior to the sawtooth crash. One model is based on the magnetic reconnection model of Kadomtsev. The other involves ideal MHD motion only. In cases where differences in magnetic topology between the two models cannot be seen in the tomograms, the analysis of profile flattening has an advantage. The analysis shows that in RTP the clearly observed m=1 displacement of some sawteeth requires the presence of convective ideal MHD motion, whereas other precursors are consistent with magnetic reconnection of up to 75% of the magnetic flux within the q=1 surface. The possibility of ideal interchange combined with enhanced cross-field transport is not excluded. copyright 1997 American Institute of Physics

  15. Computer tomographic and sonographic diagnosis of echinococcus

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, K.; Huebener, K.H.; Klott, K.; Jenss, H.; Baehr, R. (Tuebingen Univ. (Germany, F.R.). Medizinisches Strahleninstitut und Roentgenabteilung; Tuebingen Univ. (Germany, F.R.). Medizinische Klinik; Tuebingen Univ. (Germany, F.R.). Chirurgische Klinik und Poliklinik)

    1980-05-01

    In 33 patients (18 cystic echinococci, 15 alveolar) both methods produced the following findings which could be correlated with the pathological results: single or multi-centric lesions, sharp or indefinite demarkation and abnormalities in the shape and size of the liver. The sonographic findings were analysed with respect to the echo characteristics, whereas the computer tomographically demonstrated lesions were examined densitometrically in order to show calcification. Both methods demonstrate the pathological changes satisfactorily. Computer tomography is more effective in alveolar echinococcus lesions by showing the different types of calcification, whereas sonography provides a more accurate picture of the internal structure of the cysts in cystic echinococcus. Comparison of the methods in 19 patients examined by both showed a high accuracy in each method, but sonography was relatively poor in demonstrating lesions in the spleen.

  16. Computed tomographic investigations on intraventricular hematomas

    International Nuclear Information System (INIS)

    Laber-Szillat, S.

    1982-01-01

    This work investigated in 106 patients with intraventricular hematomas all the known factors which can have an influence on prognosis: age, sex, anamnesis of the patients, size, extent and localization of the intracranial bleeding, underlying angiopathy and differences between arterial and venous and spontaneous and traumatic bleedings. It was shown that the state of mind was the deciding prognostic factor, whereby viligance was the cumulative expression of all other investigated influences. A computed tomography (CT) examination is deciding in the question of operative hydrocephalus care. In 13 patients it was further shown, how clearly CT results and brain dissection allowed themselves to be compared. The computed tomographic examination method is best suited to achieve even physiological and more extensive prognostic possibilities. (orig.) [de

  17. Tomographic reconstruction of OH* chemiluminescence in two interacting turbulent flames

    International Nuclear Information System (INIS)

    Worth, Nicholas A; Dawson, James R

    2013-01-01

    The tomographic reconstruction of OH* chemiluminescence was performed on two interacting turbulent premixed bluff-body stabilized flames under steady flow conditions and acoustic excitation. These measurements elucidate the complex three-dimensional (3D) vortex–flame interactions which have previously not been accessible. The experiment was performed using a single camera and intensifier, with multiple views acquired by repositioning the camera, permitting calculation of the mean and phase-averaged volumetric OH* distributions. The reconstructed flame structure and phase-averaged dynamics are compared with OH planar laser-induced fluorescence and flame surface density measurements for the first time. The volumetric data revealed that the large-scale vortex–flame structures formed along the shear layers of each flame collide when the two flames meet, resulting in complex 3D flame structures in between the two flames. With a fairly simple experimental setup, it is shown that the tomographic reconstruction of OH* chemiluminescence in forced flames is a powerful tool that can yield important physical insights into large-scale 3D flame dynamics that are important in combustion instability. (paper)

  18. Tomographic reconstruction of the time-averaged density distribution in two-phase flow

    International Nuclear Information System (INIS)

    Fincke, J.R.

    1982-01-01

    The technique of reconstructive tomography has been applied to the measurement of time-average density and density distribution in a two-phase flow field. The technique of reconstructive tomography provides a model-independent method of obtaining flow-field density information. A tomographic densitometer system for the measurement of two-phase flow has two unique problems: a limited number of data values and a correspondingly coarse reconstruction grid. These problems were studied both experimentally through the use of prototype hardware on a 3-in. pipe, and analytically through computer generation of simulated data. The prototype data were taken on phantoms constructed of all Plexiglas and Plexiglas laminated with wood and polyurethane foam. Reconstructions obtained from prototype data are compared with reconstructions from the simulated data. Also presented are some representative results in a horizontal air/water flow

  19. Bone densitometry with the computer tomograph

    International Nuclear Information System (INIS)

    Weiss, T.

    1978-01-01

    This work tests the usefulness of the EMI head scanner MARK I for a quantitative detection of ossary mineral content. Twenty-three concentration levels of a aqueous K 2 HPO 4 -solution were positioned by means of a special clamping device at the EMI-scanner and examined at tubevoltages of 100, 120 and 140 kV. This produces an almost linear dependence between CT-unit and sample concentration, whereby it shows that the measured special element densities of samples with the same densities vary in dependence with the voltage. The examination of an anotomical fore-arm preperate served as a statement for the reproductability of computer tomographic densitometry at non-moving biological objects. The test of reproductability of bone densitometry measurements under clinical conditions was made on the occation of the six time examinations of the right hand fore-arm bone of a young dummy. Furthermore densitometric examination were made at the fore-arm shelton of 40 long-time dialysis patients in the age levels between 17 and 67 years. The reproductability of the technique presented here is at least not better with the EMI-head-scanner MARK I used here. A change is possible by using the new whole body tomographs. (orig./MG) [de

  20. Experience of computed tomographic myelography and discography in cervical problem

    Energy Technology Data Exchange (ETDEWEB)

    Nakatani, Shigeru; Yamamoto, Masayuki; Uratsuji, Masaaki; Suzuki, Kunio; Matsui, Eigo [Hyogo Prefectural Awaji Hospital, Sumoto, Hyogo (Japan); Kurihara, Akira

    1983-06-01

    CTM (computed tomographic myelography) was performed on 15 cases of cervical lesions, and on 5 of them, CTD (computed tomographic discography) was also made. CTM revealed the intervertebral state, and in combination with CTD, providing more accurate information. The combined method of CTM and CTD was useful for soft disc herniation.

  1. E-learn Computed Tomographic Angiography

    DEFF Research Database (Denmark)

    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...

  2. Computed tomographic findings of cerebral arterial ectasia

    International Nuclear Information System (INIS)

    Choi, Woo Suk; Ko, Young Ho; Lim, Jae Hoon

    1987-01-01

    The computed tomographic findings of cerebral arterial ectasia in 8 patients, of which 5 cases were angiographically documented, are reported. The ecstatic arteries, located predominantly in the suprasellar and interpeduncular cisterns, appeared as serpignous, tubular structures on the unenhanced scan. The enhanced CT scan demonstrated dense, sharply defined, homogeneous intraluminal enhancement. Until recently, the diagnosis of cerebral arterial ectasia was usually established by angiography. With introduction of CT it has become possible to noninvasively identify and characterize this vascular disorder and its associated intracranial complications. The vertebrobasilar dolichoectasia may be diagnosed by CT as an extra-axial lesion in the cerebellopontine angle. It enhances in a tubular fashion after intravenous injection of contrast.

  3. Dense velocity reconstruction from tomographic PTV with material derivatives

    Science.gov (United States)

    Schneiders, Jan F. G.; Scarano, Fulvio

    2016-09-01

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

  4. Computed tomographic findings of hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Jo, In Su; Jong, Woo Yung; Lee, Jong Yul; Choi, Han Yong; Kim, Bong Ki

    1987-01-01

    With Development of Computed Tomography, detection of the Hepatocellular Carcinoma are easily performed and frequently used in the world. During 15 months, from December 1985 to February 1987, 59 patients with hepatocellular carcinoma were evaluated with computed tomography in department of radiology at Wallace Memorial Baptist Hospital. The results were as follow: 1. The most prevalent age group was 5th to 7th decades, male to female ratio was 4.9:1. 2. Classification with incidence of computed tomographic appearance of the hepatocellular carcinoma were solitary type 28 cases (48%), multinodular type 24 cases (40%), and diffuse type 7 cases (12%), Association with liver cirrhosis was noted in 22 cases (38%). 3. Inhomogenous internal consistency of hepatocellular carcinoma due to central necrosis were 35 cases (60%). Portal vein invasion by hepatocellular carcinoma was noted in 15 cases (25%), and particularly most common in diffuse type 4 cases (55%). 4. On precontrast scan, all hepatocellular carcinoma were seen as area of low density except for 3 cases(0.5%) of near isodensity which turned out to be remarkable low density on postcontrast scan. 5. In solitary type, posterior segment of right lobe was most common site of involvement 12 cases (43%). In diffuse type, bilobar involvement was most common, 6 cases (85%)

  5. Three dimensional reconstruction of tomographic images of the retina

    International Nuclear Information System (INIS)

    Glittenberg, C.; Zeiler, F.; Falkner, C.; Binder, S.; Povazay, B.; Hermann, B.; Drexler, W.

    2007-01-01

    The development of a new display system for the three-dimensional visualization of tomographic images in ophthalmology. Specifically, a system that can use stacks of B-mode scans from an ultrahigh resolution optical tomography examination to vividly display retinal specimens as three-dimensional objects. Several subroutines were programmed in the rendering and raytracing program Cinema 4D XL 9.102 Studio Bundle (Maxon Computer Inc., Friedrichsburg, Germany), which could process stacks of tomographic scans into three-dimensional objects. Ultrahigh resolution optical coherence tomography examinations were performed on patients with various retinal pathologies and post processed with the subroutines that had been designed. All ultrahigh resolution optical coherence tomographies were performed with a titanium: sapphire based ultra broad bandwidth (160 nm) femtosecond laser system (INTEGRAL, Femtolasers Productions GmbH. Vienna Austria) with an axial resolution of 3 μm. A new three dimensional display system for tomographic images in ophthalmology was developed, which allows a highly vivid display of physiological and pathological structures of the retina. The system also distinguishes itself through its high interactivity and adaptability. This new display system allows the visualization of physiological and pathological structures of the retina in a new way, which will give us new insight into their morphology and development. (author) [de

  6. Evaluation of a 3D point cloud tetrahedral tomographic reconstruction method

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, N F; Sitek, A, E-mail: nfp4@bwh.harvard.ed, E-mail: asitek@bwh.harvard.ed [Department of Radiology, Brigham and Women' s Hospital-Harvard Medical School Boston, MA (United States)

    2010-09-21

    Tomographic reconstruction on an irregular grid may be superior to reconstruction on a regular grid. This is achieved through an appropriate choice of the image space model, the selection of an optimal set of points and the use of any available prior information during the reconstruction process. Accordingly, a number of reconstruction-related parameters must be optimized for best performance. In this work, a 3D point cloud tetrahedral mesh reconstruction method is evaluated for quantitative tasks. A linear image model is employed to obtain the reconstruction system matrix and five point generation strategies are studied. The evaluation is performed using the recovery coefficient, as well as voxel- and template-based estimates of bias and variance measures, computed over specific regions in the reconstructed image. A similar analysis is performed for regular grid reconstructions that use voxel basis functions. The maximum likelihood expectation maximization reconstruction algorithm is used. For the tetrahedral reconstructions, of the five point generation methods that are evaluated, three use image priors. For evaluation purposes, an object consisting of overlapping spheres with varying activity is simulated. The exact parallel projection data of this object are obtained analytically using a parallel projector, and multiple Poisson noise realizations of these exact data are generated and reconstructed using the different point generation strategies. The unconstrained nature of point placement in some of the irregular mesh-based reconstruction strategies has superior activity recovery for small, low-contrast image regions. The results show that, with an appropriately generated set of mesh points, the irregular grid reconstruction methods can out-perform reconstructions on a regular grid for mathematical phantoms, in terms of the performance measures evaluated.

  7. Evaluation of a 3D point cloud tetrahedral tomographic reconstruction method

    Science.gov (United States)

    Pereira, N. F.; Sitek, A.

    2010-09-01

    Tomographic reconstruction on an irregular grid may be superior to reconstruction on a regular grid. This is achieved through an appropriate choice of the image space model, the selection of an optimal set of points and the use of any available prior information during the reconstruction process. Accordingly, a number of reconstruction-related parameters must be optimized for best performance. In this work, a 3D point cloud tetrahedral mesh reconstruction method is evaluated for quantitative tasks. A linear image model is employed to obtain the reconstruction system matrix and five point generation strategies are studied. The evaluation is performed using the recovery coefficient, as well as voxel- and template-based estimates of bias and variance measures, computed over specific regions in the reconstructed image. A similar analysis is performed for regular grid reconstructions that use voxel basis functions. The maximum likelihood expectation maximization reconstruction algorithm is used. For the tetrahedral reconstructions, of the five point generation methods that are evaluated, three use image priors. For evaluation purposes, an object consisting of overlapping spheres with varying activity is simulated. The exact parallel projection data of this object are obtained analytically using a parallel projector, and multiple Poisson noise realizations of these exact data are generated and reconstructed using the different point generation strategies. The unconstrained nature of point placement in some of the irregular mesh-based reconstruction strategies has superior activity recovery for small, low-contrast image regions. The results show that, with an appropriately generated set of mesh points, the irregular grid reconstruction methods can out-perform reconstructions on a regular grid for mathematical phantoms, in terms of the performance measures evaluated.

  8. Evaluation of a 3D point cloud tetrahedral tomographic reconstruction method

    International Nuclear Information System (INIS)

    Pereira, N F; Sitek, A

    2010-01-01

    Tomographic reconstruction on an irregular grid may be superior to reconstruction on a regular grid. This is achieved through an appropriate choice of the image space model, the selection of an optimal set of points and the use of any available prior information during the reconstruction process. Accordingly, a number of reconstruction-related parameters must be optimized for best performance. In this work, a 3D point cloud tetrahedral mesh reconstruction method is evaluated for quantitative tasks. A linear image model is employed to obtain the reconstruction system matrix and five point generation strategies are studied. The evaluation is performed using the recovery coefficient, as well as voxel- and template-based estimates of bias and variance measures, computed over specific regions in the reconstructed image. A similar analysis is performed for regular grid reconstructions that use voxel basis functions. The maximum likelihood expectation maximization reconstruction algorithm is used. For the tetrahedral reconstructions, of the five point generation methods that are evaluated, three use image priors. For evaluation purposes, an object consisting of overlapping spheres with varying activity is simulated. The exact parallel projection data of this object are obtained analytically using a parallel projector, and multiple Poisson noise realizations of these exact data are generated and reconstructed using the different point generation strategies. The unconstrained nature of point placement in some of the irregular mesh-based reconstruction strategies has superior activity recovery for small, low-contrast image regions. The results show that, with an appropriately generated set of mesh points, the irregular grid reconstruction methods can out-perform reconstructions on a regular grid for mathematical phantoms, in terms of the performance measures evaluated.

  9. Tensor-based Dictionary Learning for Dynamic Tomographic Reconstruction

    Science.gov (United States)

    Tan, Shengqi; Zhang, Yanbo; Wang, Ge; Mou, Xuanqin; Cao, Guohua; Wu, Zhifang; Yu, Hengyong

    2015-01-01

    In dynamic computed tomography (CT) reconstruction, the data acquisition speed limits the spatio-temporal resolution. Recently, compressed sensing theory has been instrumental in improving CT reconstruction from far few-view projections. In this paper, we present an adaptive method to train a tensor-based spatio-temporal dictionary for sparse representation of an image sequence during the reconstruction process. The correlations among atoms and across phases are considered to capture the characteristics of an object. The reconstruction problem is solved by the alternating direction method of multipliers. To recover fine or sharp structures such as edges, the nonlocal total variation is incorporated into the algorithmic framework. Preclinical examples including a sheep lung perfusion study and a dynamic mouse cardiac imaging demonstrate that the proposed approach outperforms the vectorized dictionary-based CT reconstruction in the case of few-view reconstruction. PMID:25779991

  10. Tensor-based dictionary learning for dynamic tomographic reconstruction

    International Nuclear Information System (INIS)

    Tan, Shengqi; Wu, Zhifang; Zhang, Yanbo; Mou, Xuanqin; Wang, Ge; Cao, Guohua; Yu, Hengyong

    2015-01-01

    In dynamic computed tomography (CT) reconstruction, the data acquisition speed limits the spatio-temporal resolution. Recently, compressed sensing theory has been instrumental in improving CT reconstruction from far few-view projections. In this paper, we present an adaptive method to train a tensor-based spatio-temporal dictionary for sparse representation of an image sequence during the reconstruction process. The correlations among atoms and across phases are considered to capture the characteristics of an object. The reconstruction problem is solved by the alternating direction method of multipliers. To recover fine or sharp structures such as edges, the nonlocal total variation is incorporated into the algorithmic framework. Preclinical examples including a sheep lung perfusion study and a dynamic mouse cardiac imaging demonstrate that the proposed approach outperforms the vectorized dictionary-based CT reconstruction in the case of few-view reconstruction. (paper)

  11. Cone Beam Computed Tomographic imaging in orthodontics.

    Science.gov (United States)

    Scarfe, W C; Azevedo, B; Toghyani, S; Farman, A G

    2017-03-01

    Over the last 15 years, cone beam computed tomographic (CBCT) imaging has emerged as an important supplemental radiographic technique for orthodontic diagnosis and treatment planning, especially in situations which require an understanding of the complex anatomic relationships and surrounding structures of the maxillofacial skeleton. CBCT imaging provides unique features and advantages to enhance orthodontic practice over conventional extraoral radiographic imaging. While it is the responsibility of each practitioner to make a decision, in tandem with the patient/family, consensus-derived, evidence-based clinical guidelines are available to assist the clinician in the decision-making process. Specific recommendations provide selection guidance based on variables such as phase of treatment, clinically-assessed treatment difficulty, the presence of dental and/or skeletal modifying conditions, and pathology. CBCT imaging in orthodontics should always be considered wisely as children have conservatively, on average, a three to five times greater radiation risk compared with adults for the same exposure. The purpose of this paper is to provide an understanding of the operation of CBCT equipment as it relates to image quality and dose, highlight the benefits of the technique in orthodontic practice, and provide guidance on appropriate clinical use with respect to radiation dose and relative risk, particularly for the paediatric patient. © 2017 Australian Dental Association.

  12. Computed tomographic findings of intracerebral cysticercosis

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Computed tomographic findings of cerebral paragonimiasis

    International Nuclear Information System (INIS)

    Sung, Nak Kwan; Nam, Kyung Jin; Park, Churl Min; Eun, Chung Kie; Lee, Sun Wha

    1983-01-01

    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

  14. Computed tomographic determination of tracheal dimensions in children and adolescents

    International Nuclear Information System (INIS)

    Griscom, N.T.

    1982-01-01

    A computed tomographic system for determining the internal diameters, cross-sectional area, and length of the trachea in children and adolescents was developed. Intraluminal volumes were calculated from these measurements.The results of 18 analyses are reported

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    laboratories. Prevalence of flow-limiting CAD defined by invasive coronary angiography equal to 50% or greater with an associated single-photon emission computed tomography myocardial perfusion imaging defect was 45% (114/252) and 23% (30/129) in males and females, respectively. Patient-based diagnostic......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, we...... aimed to evaluate the diagnostic accuracy of combined coronary CTA and CTP in detecting flow-limiting CAD in women compared with men.  Methods and Results-Three hundred and eighty-one patients who underwent both CTA-CTP and single-photon emission computed tomography myocardial perfusion imaging...

  16. Radiographic test phantom for computed tomographic lung nodule analysis

    International Nuclear Information System (INIS)

    Zerhouni, E.A.

    1987-01-01

    This patent describes a method for evaluating a computed tomograph scan of a nodule in a lung of a human or non-human animal. The method comprises generating a computer tomograph of a transverse section of the animal containing lung and nodule tissue, and generating a second computer tomograph of a test phantom comprising a device which simulates the transverse section of the animal. The tissue simulating portions of the device are constructed of materials having radiographic densities substantially identical to those of the corresponding tissue in the simulated transverse section of the animal and have voids therein which simulate, in size and shape, the lung cavities in the transverse section and which contain a test reference nodule constructed of a material of predetermined radiographic density which simulates in size, shape and position within a lung cavity void of the test phantom the nodule in the transverse section of the animal and comparing the respective tomographs

  17. Computed tomographic findings of hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Eun, Chung Kie [Kyung Hee University College of Medicine, Seoul (Korea, Republic of)

    1982-09-15

    It is well known that CT is very useful in the evaluation of hepatocellular carcinoma. The computed tomographic findings of 56 patients diagnosed as hepatocellular carcinoma were reviewed and analyzed. The results were as follows: 1. The male to female ratio was 3 : 1 and the age ranged from 31 to 73 years with average age of 54 years. 2. Alpha-fetoprotein was positive in 19 out of 38 cases (50%). HBsAg was positive in 8 out of 33 cases (24%). 3. All lesions were seen as areas of low density except 1 case (0%) of isodensity, and 40 cases (72%) appeared to be solitary while 15 (26%) were multifocal. The low density was homogenous in 13 cases (24%) and inhomogenous in 42 cases (76%), and 18 cases out of 42 cases inhomogenous low density showed peripheal and/or central nodular enhancement. The additional findings were contour changes in 37 cases (66%), metastasis in 35 cases (63%), splenomegaly in 23 cases (42%) and ascities in 22 cases (39%). 4. In postcontrast scans, 41 cases (80%) out of 51 cases showed the change of density after contrast infusion. The presence and extent of tumors were better seen after contrast infusion in 30 cases (59%), better seen before contrast infusion in 11 cases (21%) and no significant difference before and after contrast infusion in 10 cases (20%). 5. The sites of involved lobe were right lobe in 38 cases (68%), left lobe in 5 cases (9%) and both lobes in 13 cases (23%). 6. 35 cases (63%) showed evidence of metastasis to regional lymph nodes, organ or tissues.

  18. Computed tomographic findings of cerebral paragonimiasis

    International Nuclear Information System (INIS)

    Bae, Weon Tae; Jung, Min Ki; Kang, Heoung Keun; Chung, Hyon De

    1988-01-01

    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.

  19. Tomographic Reconstruction from a Few Views: A Multi-Marginal Optimal Transport Approach

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, I., E-mail: isabelle.abraham@cea.fr [CEA Ile de France (France); Abraham, R., E-mail: romain.abraham@univ-orleans.fr; Bergounioux, M., E-mail: maitine.bergounioux@univ-orleans.fr [Université d’Orléans, UFR Sciences, MAPMO, UMR 7349 (France); Carlier, G., E-mail: carlier@ceremade.dauphine.fr [CEREMADE, UMR CNRS 7534, Université Paris IX Dauphine, Pl. de Lattre de Tassigny (France)

    2017-02-15

    In this article, we focus on tomographic reconstruction. The problem is to determine the shape of the interior interface using a tomographic approach while very few X-ray radiographs are performed. We use a multi-marginal optimal transport approach. Preliminary numerical results are presented.

  20. Preparation and tomographic reconstruction of an arbitrary single-photon path qubit

    International Nuclear Information System (INIS)

    Baek, So-Young; Kim, Yoon-Ho

    2011-01-01

    We report methods for preparation and tomographic reconstruction of an arbitrary single-photon path qubit. The arbitrary single-photon path qubit is prepared losslessly by passing the heralded single-photon state from spontaneous parametric down-conversion through variable beam splitter. Quantum state tomography of the single-photon path qubit is implemented by introducing path-projection measurements based on the first-order single-photon quantum interference. Using the state preparation and path-projection measurements methods for the single-photon path qubit, we demonstrate preparation and complete tomographic reconstruction of the single-photon path qubit with arbitrary purity. -- Highlights: → We report methods for preparation and tomographic reconstruction of an arbitrary single-photon path qubit. → We implement path-projection measurements based on the first-order single-photon quantum interference. → We demonstrate preparation and complete tomographic reconstruction of the single-photon path qubit with arbitrary purity.

  1. Real-time quasi-3D tomographic reconstruction

    Science.gov (United States)

    Buurlage, Jan-Willem; Kohr, Holger; Palenstijn, Willem Jan; Joost Batenburg, K.

    2018-06-01

    Developments in acquisition technology and a growing need for time-resolved experiments pose great computational challenges in tomography. In addition, access to reconstructions in real time is a highly demanded feature but has so far been out of reach. We show that by exploiting the mathematical properties of filtered backprojection-type methods, having access to real-time reconstructions of arbitrarily oriented slices becomes feasible. Furthermore, we present , software for visualization and on-demand reconstruction of slices. A user of can interactively shift and rotate slices in a GUI, while the software updates the slice in real time. For certain use cases, the possibility to study arbitrarily oriented slices in real time directly from the measured data provides sufficient visual and quantitative insight. Two such applications are discussed in this article.

  2. An efficient simultaneous reconstruction technique for tomographic particle image velocimetry

    Science.gov (United States)

    Atkinson, Callum; Soria, Julio

    2009-10-01

    To date, Tomo-PIV has involved the use of the multiplicative algebraic reconstruction technique (MART), where the intensity of each 3D voxel is iteratively corrected to satisfy one recorded projection, or pixel intensity, at a time. This results in reconstruction times of multiple hours for each velocity field and requires considerable computer memory in order to store the associated weighting coefficients and intensity values for each point in the volume. In this paper, a rapid and less memory intensive reconstruction algorithm is presented based on a multiplicative line-of-sight (MLOS) estimation that determines possible particle locations in the volume, followed by simultaneous iterative correction. Reconstructions of simulated images are presented for two simultaneous algorithms (SART and SMART) as well as the now standard MART algorithm, which indicate that the same accuracy as MART can be achieved 5.5 times faster or 77 times faster with 15 times less memory if the processing and storage of the weighting matrix is considered. Application of MLOS-SMART and MART to a turbulent boundary layer at Re θ = 2200 using a 4 camera Tomo-PIV system with a volume of 1,000 × 1,000 × 160 voxels is discussed. Results indicate improvements in reconstruction speed of 15 times that of MART with precalculated weighting matrix, or 65 times if calculation of the weighting matrix is considered. Furthermore the memory needed to store a large weighting matrix and volume intensity is reduced by almost 40 times in this case.

  3. Comparative study of the macroscopic finding, conventional tomographic imaging, and computed tomographic imaging in locating the mandibular canal

    International Nuclear Information System (INIS)

    Choi, Hang Moon; You, Dong Soo

    1995-01-01

    The purpose of this study was comparison of conventional tomography with reformatted computed tomography for dental implant in locating the mandibular canal. Five dogs were used and after conventional tomographs and fitted computed tomographs were taken, four dentist traced all films. Mandibles were sectioned with 2 mm slice thickness and the sections were then radiographed (contact radiography). Each radiograpic image was traced and linear measurements were made from mandibular canal to alveolar crest, buccal cortex, lingual cortex, and inferior border. The following results were obtained; 1. Reformatted computed tomographs were exacter than conventional tomography by alveolar crest to canal length of -0.6 mm difference between real values and radiographs 2. The average measurements of buccal cortex to mandibular canal width and lingual cortex to mandibular canal width of conventional tomographs were exacter than reformatted computed tomographs, but standard deviations were higher than reformatted computed tomographs. 3. Standard deviations of reformatted computed tomographs were lower than conventional tomographs at all comparing sites 4. At reformatted computed tomography 62.5% of the measurements performed were within ±1 mm of the true value, and at conventional tomography 24.1% were. 5. Mandibular canal invisibility was 0.8% at reformatted computed tomography and 9.2% at conventional tomography. Reformatted computed tomography has been shown to be more useful radiographic technique for assessment of the mandibular canal than conventional tomography.

  4. Effect of object functions on tomographic reconstruction a numerical study

    International Nuclear Information System (INIS)

    Babu Rao, C.; Baldev Raj; Ravichandran, V.S.; Munshi, P.

    1996-01-01

    Convolution back projection is the most widely used algorithm of computed tomography (CT). Theoretical studies show that under ideal conditions, the error in the reconstruction can be correlated with the second fourier space derivative of filter function and with the Laplacian of the object function. This paper looks into the second aspect of the error function. In this paper a systematic numerical study is presented on the effect to object functions on global and local errors. (author)

  5. TomoBank: a tomographic data repository for computational x-ray science

    Science.gov (United States)

    De Carlo, Francesco; Gürsoy, Doğa; Ching, Daniel J.; Joost Batenburg, K.; Ludwig, Wolfgang; Mancini, Lucia; Marone, Federica; Mokso, Rajmund; Pelt, Daniël M.; Sijbers, Jan; Rivers, Mark

    2018-03-01

    There is a widening gap between the fast advancement of computational methods for tomographic reconstruction and their successful implementation in production software at various synchrotron facilities. This is due in part to the lack of readily available instrument datasets and phantoms representative of real materials for validation and comparison of new numerical methods. Recent advancements in detector technology have made sub-second and multi-energy tomographic data collection possible (Gibbs et al 2015 Sci. Rep. 5 11824), but have also increased the demand to develop new reconstruction methods able to handle in situ (Pelt and Batenburg 2013 IEEE Trans. Image Process. 22 5238-51) and dynamic systems (Mohan et al 2015 IEEE Trans. Comput. Imaging 1 96-111) that can be quickly incorporated in beamline production software (Gürsoy et al 2014 J. Synchrotron Radiat. 21 1188-93). The x-ray tomography data bank, tomoBank, provides a repository of experimental and simulated datasets with the aim to foster collaboration among computational scientists, beamline scientists, and experimentalists and to accelerate the development and implementation of tomographic reconstruction methods for synchrotron facility production software by providing easy access to challenging datasets and their descriptors.

  6. The research of clinical application of computed tomographic virtual gastroscopy

    International Nuclear Information System (INIS)

    Zhang Lei; Pan Zhenyu; Zhai Xiaoli; Gu Hua; Wang Yajie; Ding Yi; Wang Li; Liang Ying; Zhai Renyou

    2000-01-01

    Objective: To investigate the values, methods and findings of computed tomographic virtual gastroscopy (CTVG). Methods: Sixty-nine patients underwent the examination of spiral CT after charged air into stomachs in different cubage. The CT scan conditions were collimating width 3 mm, pitch 1.2 - 2.5, scanning speed 0.8 s/360 degree, the raw data of CT volume scan was reconstructed in overlapping rate 33% - 67%. Then the images of CTVG were built using navigator software (GE AG, USA). Results: The accuracy, sensitivity, and specificity of CTVG were 92.8%, 96.4%, and 78.6%, respectively. CTVG corresponded well with fibrous gastroscopy and specimens in demonstrating the gastric lesions. CTVG was provided with the ability of revealing the tiny lesions of chronic atrophic gastritis, chronic erosive gastritis, chronic proliferative gastritis, and acute hemorrhagic gastritis in some degree. The high quality imaging of CTVG could be obtained in condition of collimating width 3 mm, pitch 1.2 - 1.5, overlapping 50% - 67%, well hold-breath, gastric cubage in full and feasible scan positions. Conclusion: CTVG is a rising means of gastric examination and has great value in clinic applications

  7. Tomographic image reconstruction and rendering with texture-mapping hardware

    International Nuclear Information System (INIS)

    Azevedo, S.G.; Cabral, B.K.; Foran, J.

    1994-07-01

    The image reconstruction problem, also known as the inverse Radon transform, for x-ray computed tomography (CT) is found in numerous applications in medicine and industry. The most common algorithm used in these cases is filtered backprojection (FBP), which, while a simple procedure, is time-consuming for large images on any type of computational engine. Specially-designed, dedicated parallel processors are commonly used in medical CT scanners, whose results are then passed to graphics workstation for rendering and analysis. However, a fast direct FBP algorithm can be implemented on modern texture-mapping hardware in current high-end workstation platforms. This is done by casting the FBP algorithm as an image warping operation with summing. Texture-mapping hardware, such as that on the Silicon Graphics Reality Engine (TM), shows around 600 times speedup of backprojection over a CPU-based implementation (a 100 Mhz R4400 in this case). This technique has the further advantages of flexibility and rapid programming. In addition, the same hardware can be used for both image reconstruction and for volumetric rendering. The techniques can also be used to accelerate iterative reconstruction algorithms. The hardware architecture also allows more complex operations than straight-ray backprojection if they are required, including fan-beam, cone-beam, and curved ray paths, with little or no speed penalties

  8. Acceleration of iterative tomographic reconstruction using graphics processors

    International Nuclear Information System (INIS)

    Belzunce, M.A.; Osorio, A.; Verrastro, C.A.

    2009-01-01

    Using iterative algorithms for image reconstruction in 3 D Positron Emission Tomography has shown to produce images with better quality than analytical methods. How ever, these algorithms are computationally expensive. New Graphic Processor Units (GPU) provides high performance at low cost and also programming tools that make possible to execute parallel algorithms easily in scientific applications. In this work, we try to achieve an acceleration of image reconstruction algorithms in 3 D PET by using a GPU. A parallel implementation of the algorithm ML-EM 3 D was developed using Siddon algorithm as Projector and Back-projector. Results show that accelerations of more than one order of magnitude can be achieved, keeping similar image quality. (author)

  9. Computed tomographic diagnosis of abdominal abscess in childhood

    International Nuclear Information System (INIS)

    Kuhn, J.P.; Berger, P.E.

    1980-01-01

    Twenty-eight children suspected clinically of having an abdominal abscess were examined by CT. Eighteen had gallium 67 citrate scans and 22 had ultrasound studies. Computed tomography was found to be the most accurate test for diagnosis and evaluation of an abscess and the computed tomographic appearance of abscess is illustrated. However, because of cost factors, radiation dose, and clinical considerations, computed tomography is not always the first modality of choice in evaluating a suspected abdominal abscess [fr

  10. Analytical algorithm for the generation of polygonal projection data for tomographic reconstruction

    International Nuclear Information System (INIS)

    Davis, G.R.

    1996-01-01

    Tomographic reconstruction algorithms and filters can be tested using a mathematical phantom, that is, a computer program which takes numerical data as its input and outputs derived projection data. The input data is usually in the form of pixel ''densities'' over a regular grid, or position and dimensions of simple, geometrical objects. The former technique allows a greater variety of objects to be simulated, but is less suitable in the case when very small (relative to the ray-spacing) features are to be simulated. The second technique is normally used to simulate biological specimens, typically a human skull, modelled as a number of ellipses. This is not suitable for simulating non-biological specimens with features such as straight edges and fine cracks. We have therefore devised an algorithm for simulating objects described as a series of polygons. These polygons, or parts of them, may be smaller than the ray-spacing and there is no limit, except that imposed by computing resources, on the complexity, number or superposition of polygons. A simple test of such a phantom, reconstructed using the filtered back-projection method, revealed reconstruction artefacts not normally seen with ''biological'' phantoms. (orig.)

  11. Computed tomographic findings in manifesting carriers of Duchenne muscular dystrophy

    NARCIS (Netherlands)

    de Visser, M.; Verbeeten, B.

    1985-01-01

    Clinical and computed tomographic (CT) findings in 3 manifesting carriers of Duchenne muscular dystrophy are reported. CT proved to be an important adjunct to the clinical examination: in all our 3 cases a decrease in density was found in various non-paretic muscles

  12. The inverse problems of reconstruction in the X-rays, gamma or positron tomographic imaging systems

    International Nuclear Information System (INIS)

    Grangeat, P.

    1999-01-01

    The revolution in imagery, brought by the tomographic technic in the years 70, allows the computation of local values cartography for the attenuation or the emission activity. The reconstruction techniques thus allow the connection from integral measurements to characteristic information distribution by inversion of the measurement equations. They are a main application of the solution technic for inverse problems. In a first part the author recalls the physical principles for measures in X-rays, gamma and positron imaging. Then he presents the various problems with their associated inversion techniques. The third part is devoted to the activity sector and examples, to conclude in the last part with the forecast. (A.L.B.)

  13. Tomographic ventricular reconstruction using multiple view first-pass radionuclide angiography

    International Nuclear Information System (INIS)

    Lacy, J.L.; Ball, M.E.; Verani, M.S.; Wiles, H.; Roberts, R.

    1985-01-01

    In first-pass radionuclide angiography (FPRA) images of both left and right ventricles are uncontaminated by adjacent structures. Thus, the problem of tomographic reconstruction is vastly simplified compared to equilibrium blood pool imaging in which all structures are imaged simultaneously. Tomographic reconstruction from a limited number of views may thus be possible. A simple filtered interpolative back-projection reconstruction technique was employed. In this technique interpolation was used between sectional distributions at successive angles. Interpolations yielding 9 and 13 back projection angles of 22.5 0 and 15 0 were evaluated. Ventricular borders were obtained in each back-projected tomographic slice by location of the intensity level which provided correct total ventricular volume. Cast cross sections were quantitatively well represented by these borders. This ventricular border definition algorithm forms the basis for applications of the technique in animals and humans

  14. Novel edge treatment method for improving the transmission reconstruction quality in Tomographic Gamma Scanning.

    Science.gov (United States)

    Han, Miaomiao; Guo, Zhirong; Liu, Haifeng; Li, Qinghua

    2018-05-01

    Tomographic Gamma Scanning (TGS) is a method used for the nondestructive assay of radioactive wastes. In TGS, the actual irregular edge voxels are regarded as regular cubic voxels in the traditional treatment method. In this study, in order to improve the performance of TGS, a novel edge treatment method is proposed that considers the actual shapes of these voxels. The two different edge voxel treatment methods were compared by computing the pixel-level relative errors and normalized mean square errors (NMSEs) between the reconstructed transmission images and the ideal images. Both methods were coupled with two different interative algorithms comprising Algebraic Reconstruction Technique (ART) with a non-negativity constraint and Maximum Likelihood Expectation Maximization (MLEM). The results demonstrated that the traditional method for edge voxel treatment can introduce significant error and that the real irregular edge voxel treatment method can improve the performance of TGS by obtaining better transmission reconstruction images. With the real irregular edge voxel treatment method, MLEM algorithm and ART algorithm can be comparable when assaying homogenous matrices, but MLEM algorithm is superior to ART algorithm when assaying heterogeneous matrices. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Tomographic anthropomorphic models. Pt. 2. Organ doses from computed tomographic examinations in paediatric radiology

    International Nuclear Information System (INIS)

    Zankl, M.; Panzer, W.; Drexler, G.

    1993-11-01

    This report provides a catalogue of organ dose conversion factors resulting from computed tomographic (CT) examinations of children. Two radiation qualities and two exposure geometries were simulated as well as the use of asymmetrical beams. The use of further beam shaping devices was not considered. The organ dose conversion factors are applicable to babies at the age of ca. 2 months and to children between 5 and 7 years but can be used for other ages as well with the appropriate adjustments. For the calculations, the patients were represented by the GSF tomographic anthropomorphic models BABY and CHILD. The radiation transport in the body was simulated using a Monte Carlo method. The doses are presented as conversion factors of mean organ doses per air kerma free in air on the axis of rotation. Mean organ dose conversion factors are given per organ and per scanned body section of 1 cm height. The mean dose to an organ resulting from a particular CT examination can be estimated by summing up the contributions to the organ dose from all relevant sections. To facilitate the selection of the appropriate sections, a table is given which relates the tomographic models' coordinates to certain anatomical landmarks in the human body. (orig.)

  16. The CDD system in computed tomographic diagnosis of diverticular disease

    International Nuclear Information System (INIS)

    Pustelnik, Daniel; Elsholtz, Fabian Henry Juergen; Hamm, Bernd; Niehues, Stefan Markus; Bojarski, Christian

    2017-01-01

    Purpose cation in computed tomographic diagnosis and briefly recapitulates its targeted advantages over preliminary systems. Primarily, application of the CDD in computed tomography diagnostics is described. Differences with respect to the categories of the older systems are pointed out on the level of each CDD type using imaging examples. The presented images are derived from our institute according to the S2k criteria. Literature was researched on PubMed. Results The CDD constitutes an improvement compared to older systems for categorizing the stages of diverticular disease. It provides more discriminatory power on the descriptive-morphological level and defines as well as differentiates more courses of the disease. Furthermore, the categories translate more directly into state-of-the-art decision-making concerning hospitalization and therapy. The CDD should be applied routinely in the computed tomographic diagnosis of diverticular disease. Typical imaging patterns are presented.

  17. Imaging of turbulent structures and tomographic reconstruction of TORPEX plasma emissivity

    International Nuclear Information System (INIS)

    Iraji, D.; Furno, I.; Fasoli, A.; Theiler, C.

    2010-01-01

    In the TORPEX [A. Fasoli et al., Phys. Plasmas 13, 055902 (2006)], a simple magnetized plasma device, low frequency electrostatic fluctuations associated with interchange waves, are routinely measured by means of extensive sets of Langmuir probes. To complement the electrostatic probe measurements of plasma turbulence and study of plasma structures smaller than the spatial resolution of probes array, a nonperturbative direct imaging system has been developed on TORPEX, including a fast framing Photron-APX-RS camera and an image intensifier unit. From the line-integrated camera images, we compute the poloidal emissivity profile of the plasma by applying a tomographic reconstruction technique using a pixel method and solving an overdetermined set of equations by singular value decomposition. This allows comparing statistical, spectral, and spatial properties of visible light radiation with electrostatic fluctuations. The shape and position of the time-averaged reconstructed plasma emissivity are observed to be similar to those of the ion saturation current profile. In the core plasma, excluding the electron cyclotron and upper hybrid resonant layers, the mean value of the plasma emissivity is observed to vary with (T e ) α (n e ) β , in which α=0.25-0.7 and β=0.8-1.4, in agreement with collisional radiative model. The tomographic reconstruction is applied to the fast camera movie acquired with 50 kframes/s rate and 2 μs of exposure time to obtain the temporal evolutions of the emissivity fluctuations. Conditional average sampling is also applied to visualize and measure sizes of structures associated with the interchange mode. The ω-time and the two-dimensional k-space Fourier analysis of the reconstructed emissivity fluctuations show the same interchange mode that is detected in the ω and k spectra of the ion saturation current fluctuations measured by probes. Small scale turbulent plasma structures can be detected and tracked in the reconstructed emissivity

  18. Typical computer tomographic findings in neurofibromatosis

    International Nuclear Information System (INIS)

    Allgayer, B.; Reiser, M.; Kramann, B.

    1984-01-01

    Three pateints with neurofibromatosis (Recklinghausen's disease) were examined by computer tomography. In this way, the exact extent and localisation of the neurofibromatous tumours could be demonstrated. In one patient, CT provided evidence of malignant change; this was verified histologically. The appearances of neurofibromatosis associated with elephantiasis is described. In each patient, treatment was significantly influenced by computer tomography. (orig.) [de

  19. Typical computer tomographic findings in neurofibromatosis

    Energy Technology Data Exchange (ETDEWEB)

    Allgayer, B.; Reiser, M.; Kramann, B.

    1984-06-01

    Three pateints with neurofibromatosis (Recklinghausen's disease) were examined by computer tomography. In this way, the exact extent and localisation of the neurofibromatous tumours could be demonstrated. In one patient, CT provided evidence of malignant change; this was verified histologically. The appearances of neurofibromatosis associated with elephantiasis is described. In each patient, treatment was significantly influenced by computer tomography.

  20. Development of a portable computed tomographic scanner for on-line imaging of industrial piping systems

    International Nuclear Information System (INIS)

    Jaafar Abdullah; Mohd Arif Hamzah; Mohd Soyapi Mohd Yusof; Mohd Fitri Abdul Rahman; Fadil IsmaiI; Rasif Mohd Zain

    2003-01-01

    Computed tomography (CT) technology is being increasingly developed for industrial application. This paper presents the development of a portable computed tomographic scanner for on?line imaging of industrial piping systems. The theoretical approach, the system hardware, the data acquisition system and the adopted algorithm for image reconstruction are discussed. The scanner has large potential to be used to determine the extent of corrosion under insulation (CUI), to detect blockages, to measure the thickness of deposit/materials built-up on the walls and to improve understanding of material flow in pipelines. (Author)

  1. An efficient reconstruction algorithm for differential phase-contrast tomographic images from a limited number of views

    International Nuclear Information System (INIS)

    Sunaguchi, Naoki; Yuasa, Tetsuya; Gupta, Rajiv; Ando, Masami

    2015-01-01

    The main focus of this paper is reconstruction of tomographic phase-contrast image from a set of projections. We propose an efficient reconstruction algorithm for differential phase-contrast computed tomography that can considerably reduce the number of projections required for reconstruction. The key result underlying this research is a projection theorem that states that the second derivative of the projection set is linearly related to the Laplacian of the tomographic image. The proposed algorithm first reconstructs the Laplacian image of the phase-shift distribution from the second-derivative of the projections using total variation regularization. The second step is to obtain the phase-shift distribution by solving a Poisson equation whose source is the Laplacian image previously reconstructed under the Dirichlet condition. We demonstrate the efficacy of this algorithm using both synthetically generated simulation data and projection data acquired experimentally at a synchrotron. The experimental phase data were acquired from a human coronary artery specimen using dark-field-imaging optics pioneered by our group. Our results demonstrate that the proposed algorithm can reduce the number of projections to approximately 33% as compared with the conventional filtered backprojection method, without any detrimental effect on the image quality

  2. Computed-tomographic determination of mineral content of bones

    International Nuclear Information System (INIS)

    Delov, I.; Tabakov, S.

    1988-01-01

    The problem of precise computed-tomographic densitometry of the mineral content of bones is pointed out. A method is proposed including the use of standard density and observance of definite radiation, scanning and image estimation parameters. A good correlation of the results obtained for the mineral content of the lumbar vertebrae with literature data are reported. A method is also described for determining the mineral content of tubular bones based on densiprofile check-up of the computed-tomographic density. The procedure takes 10-15 minutes and includes 1 or 2 scans. It might therefore gain wide acceptance for the diagnosis and tracing of osteoporosis and other osteopathies associated with distrorted calcium metabolism

  3. Computed tomographic diagnosis of pulmonary artery aneurysm

    International Nuclear Information System (INIS)

    Maeno, Kouji; Kontani, Kazuhiro; Ito, Makoto; Sakurai, Noboru; Sawada, Taisei; Fukeda, Yasuhiko; Takata, Shigeo; Ikeda, Takayuki; Hattori, Nobu.

    1986-01-01

    Pulmonary artery aneurysms are rare lesions. Clagett et al reported that one aneurysm of the pulmonary artery may be found in approximately 14,000 necropsies. We have experienced a case of giant pulmonary artery aneurysm confirmed by computed tomography. A 38 year-old man with atrial septal defect admitted to Kanazawa City Hospital. He had been pointed out of a right hilar mass when he was 26 years old. His complaint was bloody sputum and cough. Pulmonary angiography was not useful for the definite diagnosis because of its mural thrombi. Enhanced computed tomography showed a giant pulmonary artery aneurysm with a mural thrombi in its cavity. This shows that enhanced computed tomography is very useful for the diagnosis of a pulmonary artery aneurysm with a mural thrombi in its cavity. (author)

  4. Computed tomographic diagnosis of pulmonary artery aneurysm

    Energy Technology Data Exchange (ETDEWEB)

    Maeno, Kouji; Kontani, Kazuhiro; Ito, Makoto; Sakurai, Noboru; Sawada, Taisei; Fukeda, Yasuhiko; Takata, Shigeo; Ikeda, Takayuki; Hattori, Nobu

    1986-05-01

    Pulmonary artery aneurysms are rare lesions. Clagett et al reported that one aneurysm of the pulmonary artery may be found in approximately 14,000 necropsies. We have experienced a case of giant pulmonary artery aneurysm confirmed by computed tomography. A 38 year-old man with atrial septal defect admitted to Kanazawa City Hospital. He had been pointed out of a right hilar mass when he was 26 years old. His complaint was bloody sputum and cough. Pulmonary angiography was not useful for the definite diagnosis because of its mural thrombi. Enhanced computed tomography showed a giant pulmonary artery aneurysm with a mural thrombi in its cavity. This shows that enhanced computed tomography is very useful for the diagnosis of a pulmonary artery aneurysm with a mural thrombi in its cavity.

  5. Computer tomographic investigations of cervical spinal stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Rodiek, S.O.

    1983-10-01

    Computed tomography was applied in 29 patients with cervical spinal stenosis. In 8 cases there was a congenital narrowed spinal canal. In 18 cases we found dorsal spondylotic ridges of the vertebral bodies and in three cases an atlanto-dental dislocation. The complaints showed either radicular character or in case of myelopathy came out as para- and quadriplegia. In 25 cases the spinal sagittal diamter was a lot below a critical borderline of about 13 mm. The kind and localisation of the underlying process can be demonstrated very excellent by computed tomography.

  6. Computer tomographic investigations of cervical spinal stenosis

    International Nuclear Information System (INIS)

    Rodiek, S.O.

    1983-01-01

    Computed tomography was applied in 29 patients with cervical spinal stenosis. In 8 cases there was a congenital narrowed spinal canal. In 18 cases we found dorsal spondylotic ridges of the vertebral bodies and in three cases an atlanto-dental dislocation. The complaints showed either radicular character or in case of myelopathy came out as para- and quadriplegia. In 25 cases the spinal sagittal diamter was a lot below a critical borderline of about 13 mm. The kind and localisation of the underlying process can be demonstrated very excellent by computed tomography. (orig.) [de

  7. Computer tomographic evaluation of digestive tract non-Hodgkin lymphomas.

    Science.gov (United States)

    Lupescu, Ioana G; Grasu, Mugur; Goldis, Gheorghe; Popa, Gelu; Gheorghe, Cristian; Vasilescu, Catalin; Moicean, Andreea; Herlea, Vlad; Georgescu, Serban A

    2007-09-01

    Computer Tomographic (CT) study is crucial for defining distribution, characteristics and staging of primary gastrointestinal lymphomas. The presence of multifocal sites, the wall thickening with diffuse infiltration of the affected gastrointestinal (GI) segment in association with regional adenopathies, permit the orientation of the CT diagnosis for primary GI lymphomas. The gold standard for diagnosis remains, in all cases of digestive tract non-Hodgkin lymphomas (NHL), the histological examination, which allows a tissue diagnosis, performed preferably by transmural biopsy.

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

    Science.gov (United States)

    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.

  9. Soil structure characterized using computed tomographic images

    Science.gov (United States)

    Zhanqi Cheng; Stephen H. Anderson; Clark J. Gantzer; J. W. Van Sambeek

    2003-01-01

    Fractal analysis of soil structure is a relatively new method for quantifying the effects of management systems on soil properties and quality. The objective of this work was to explore several methods of studying images to describe and quantify structure of soils under forest management. This research uses computed tomography and a topological method called Multiple...

  10. Computed tomographic findings in penetrating peptic ulcer

    International Nuclear Information System (INIS)

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

    1984-01-01

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

  11. Tomographic reconstruction of transverse phase space from turn-by-turn profile data

    CERN Document Server

    Hancock, S; Lindroos, M

    1999-01-01

    Tomographic methods have the potential for useful application in beam diagnostics. The tomographic reconstruction of transverse phase space density from turn-by-turn profile data has been studied with particular attention to the effects of dispersion and chromaticity. It is shown that the modified Algebraic Reconstruction Technique (ART) that deals successfully with the problem of non-linear motion in the longitudinal plane cannot, in general, be extended to cover the transverse case. Instead, an approach is proposed in which the effect of dispersion is deconvoluted from the measured profiles before the phase space picture is reconstructed using either the modified ART algorithm or the inverse Radon Transform. This requires an accurate knowledge of the momentum distribution of the beam and the modified ART reconstruction of longitudinal phase space density yields just such information. The method has been tested extensively with simulated data.

  12. COMPUTED TOMOGRAPHIC EVALUATION OF CANINE PHARYNGEAL NEOPLASIA

    OpenAIRE

    Carozzi, Gregorio

    2016-01-01

    Computed tomography (CT) is commonly used to investigate head tumours in dogs, and is a fundamental part of the diagnostic work-up, for diagnosis, staging and planning therapy in neoplastic disease. Nasal diseases, either neoplastic or non-neoplastic diseases, oral neoplasia, brain disease, thyroid or carotid body neoplasia have been extensively studied. However little information are available for lesions of the pharyngeal area. In this thesis, cases of dogs affected by pharyngeal neoplas...

  13. Computed tomographic pelvimetry in English bulldogs.

    Science.gov (United States)

    Dobak, Tetyda P; Voorhout, George; Vernooij, Johannes C M; Boroffka, Susanne A E B

    2018-05-31

    English bulldogs have been reported to have a high incidence of dystocia and caesarean section is often performed electively in this breed. A narrow pelvic canal is the major maternal factor contributing to obstructive dystocia. The objective of this cross-sectional study was to assess the pelvic dimensions of 40 clinically healthy English bulldogs using computed tomography pelvimetry. A control group consisting of 30 non-brachycephalic dogs that underwent pelvic computed tomography was retrospectively collected from the patient archive system. Univariate analysis of variance was used to compare computed tomography pelvimetry of both groups and the effects of weight and gender on the measurements. In addition, ratios were obtained to address pelvic shape differences. A significantly (P = 0.00) smaller pelvic size was found in English bulldogs compared to the control group for all computed tomography measurements: width and length of the pelvis, pelvic inlet and caudal pelvic aperture. The pelvic conformation was significantly different between the groups, English bulldogs had an overall shorter pelvis and pelvic canal and a narrower pelvic outlet. Weight had a significant effect on all measurements whereas gender that only had a significant effect on some (4/11) pelvic dimensions. Our findings prove that English bulldogs have a generally reduced pelvic size as well as a shorter pelvis and narrower pelvic outlet when compared to non-brachycephalic breeds. We suggest that some of our measurements may serve as a baseline for pelvic dimensions in English bulldogs and may be useful for future studies on dystocia in this breed. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. Connections model for tomographic images reconstruction; Modelo conexionista para reconstrucao de imagens tomograficas

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, R.G.S.; Pela, C.A.; Roque, S.F. A.C. [Departamento de Fisica e Matematica (FFCLRP) USP. Av. Bandeirantes, 3900- 14040- 901- Ribeirao Preto, Sao Paulo (Brazil)

    1998-12-31

    This paper shows an artificial neural network with an adequately topology for tomographic image reconstruction. The associated error function is derived and the learning algorithm is make. The simulated results are presented and demonstrate the existence of a generalized solution for nets with linear activation function. (Author)

  15. A Penalization Approach for Tomographic Reconstruction of Binary Axially Symmetric Objects

    International Nuclear Information System (INIS)

    Abraham, R.; Bergounioux, M.; Trelat, E.

    2008-01-01

    We propose a variational method for tomographic reconstruction of blurred and noised binary images based on a penalization process of a minimization problem settled in the space of bounded variation functions. We prove existence and/or uniqueness results and derive a penalized optimality system. Numerical simulations are provided to demonstrate the relevance of the approach

  16. Positron transaxial emission tomograph with computerized image reconstruction

    International Nuclear Information System (INIS)

    Jatteau, Michel.

    1981-01-01

    This invention concerns a positron transaxial emission tomography apparatus with computerized image reconstruction, like those used in nuclear medicine for studying the metabolism of organs, in physiological examinations and as a diagnosis aid. The operation is based on the principle of the detection of photons emitted when the positrons are annihilated by impact with an electron. The appliance is mainly composed of: (a) - a set of gamma ray detectors distributed on a polygonal arrangement around the body area to be examined, (b) - circuits for amplifying the signals delivered by the gamma ray detectors, (c) - computers essentially comprising energy integration and discrimination circuits and provided at the output of the detectors for calculating and delivering, as from the amplified signals, information on the position and energy relative to each occurrence constituted by the detections of photons, (d) - time coincidence circuits for selecting by emission of detector validation signals, only those occurrences, among the ensemble of those detected, which effectively result from the annihilation of positrons inside the area examined, (e) - a data processing system [fr

  17. Computed tomographic diagnosis of the splenic trauma

    International Nuclear Information System (INIS)

    Suzuki, Masayuki; Takashima, Tsutomu; Funaki, Hiromi; Uogishi, Makoto; Isobe, Tsugimasa; Kanno, Shoichi; Ushitani, Kenji; Fuchuh, Kosei; Sakita, Tsuyoshi.

    1985-01-01

    Three cases (3-year-old, 51-year-old and 17-year-old males) in which splenic trauma was diagnosed by plain computed tomography (CT) are presented. CT images revealed retention of fluid in the abdominal cavity in all cases and clear splenic hematoma and laceration in one case. CT is superior in the visualization of splenic hematoma and hemorrhage in the abdominal cavity accompanied by splenic trauma. It should, however, be noted that the presence of laceration is frequently difficult to detect due to artifacts. Indication for surgery should be decided by evaluating the severity of clinical symptoms. (Namekawa, K.)

  18. Computed tomographic diagnosis of the splenic trauma

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Masayuki; Takashima, Tsutomu; Funaki, Hiromi; Uogishi, Makoto; Isobe, Tsugimasa; Kanno, Shoichi; Ushitani, Kenji; Fuchuh, Kosei; Sakita, Tsuyoshi

    1985-01-01

    Three cases (3-year-old, 51-year-old and 17-year-old males) in which splenic trauma was diagnosed by plain computed tomography (CT) are presented. CT images revealed retention of fluid in the abdominal cavity in all cases and clear splenic hematoma and laceration in one case. CT is superior in the visualization of splenic hematoma and hemorrhage in the abdominal cavity accompanied by splenic trauma. It should, however, be noted that the presence of laceration is frequently difficult to detect due to artifacts. Indication for surgery should be decided by evaluating the severity of clinical symptoms. (Namekawa, K.).

  19. Computer tomographic anatomy of the neck

    International Nuclear Information System (INIS)

    Koenig, R.

    1984-01-01

    The structures in the neck which can be recognised by computer tomography, and their course, is described. The cartilagenous larynx and trachea, the oesophagus, thyroid, sternocleidomastoid muscle, common carotid arteries and internal jugular veins can be recognised regularly. In addition, one can identify smaller muscles, vessels and nerves, such as the sterno-hyoid, omo-hyoid, anterior and medial scalenus muscles, the superior and inferior thyroid arteries and the suprascapular, internal thoracic and vertebral arteries, the thyro-cervical trunk and the vagus and phrenic nerves. An accurate knowledge of the anatomy is essential for the recognition of enlarged parathyroid glands. (orig.) [de

  20. Computer tomographic anatomy of the neck

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, R.

    1984-01-01

    The structures in the neck which can be recognised by computer tomography, and their course, is described. The cartilagenous larynx and trachea, the oesophagus, thyroid, sternocleidomastoid muscle, common carotid arteries and internal jugular veins can be recognised regularly. In addition, one can identify smaller muscles, vessels and nerves, such as the sterno-hyoid, omo-hyoid, anterior and medial scalenus muscles, the superior and inferior thyroid arteries and the suprascapular, internal thoracic and vertebral arteries, the thyro-cervical trunk and the vagus and phrenic nerves. An accurate knowledge of the anatomy is essential for the recognition of enlarged parathyroid glands.

  1. Computed tomographic findings in pancreatic pathology

    International Nuclear Information System (INIS)

    Frija, J.; Laval-Jeantet, M.; Larde, D.; Mathieu, D.

    1986-01-01

    Computed tomography (CT) is actually the most suitable examination for the study of the pancreas. The evolution during the life of its thickness is studied. For the same age group pancreas sharpens from the head to the body and the tail. Pancreas progressively sharpens during the life. The comparison of the efficacy of the other imaging modalities is studied. The indications of the radiological examinations of the pancreas are evaluated during acute and chronic pancreatitis, pseudocysts, adenocarcinoma of the pancreas and endocrine tumors of the pancreas [fr

  2. Spectrometry and emission tomographic image reconstruction stimulated by neutrons via EM algorithm and Monte Carlo Method

    International Nuclear Information System (INIS)

    Viana, Rodrigo Sartorelo Salemi

    2014-01-01

    The NSECT (Neutron Stimulated Emission Computed Tomography) figures as a new spectrographic technique able to evaluate in vivo the concentration of elements using the inelastic scattering reaction (n,n'). Since its introduction, several improvements have been proposed with the aim of investigating applications for clinical diagnosis and reduction of absorbed dose associated with CT acquisition. In this context, two new diagnostic applications are presented using spectroscopic and tomographic approaches from NSECT. A new methodology has also been proposed to optimize the sinogram sampling that is directly related to the quality of the reconstruction by the irradiation protocol. The studies were developed based on simulations with MCNP5 code. Diagnosis of Renal Cell Carcinoma (RCC) and the detection of breast microcalcifications were evaluated in studies conducted using a human phantom. The obtained results demonstrate the ability of the NSECT technique to detect changes in the composition of the modeled tissues as a function of the development of evaluated pathologies. The proposed method for optimizing sinograms was able to analytically simulate the composition of the irradiated medium allowing the assessment of quality of reconstruction and effective dose in terms of the sampling rate. However, future research must be conducted to quantify the sensitivity of detection according to the selected elements. (author)

  3. Computed tomographic appearance of resectable pancreatic carcinoma

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  4. Computed tomographic evaluation of the pancreas

    International Nuclear Information System (INIS)

    Stanley, R.J.; Sagel, S.S.

    1979-01-01

    Analysis of the clinical experience in the evaluation of the pancreas with computed tomography (CT) since October 1975 indicates that it is a reliable, often specific and relatively noninvasive method for the detection of pancreatic neoplasms and the varied manifestations of pancreatitis and its complications. The normal pancreas is clearly imaged in all but the leanest or uncooperative patients. Tumors of pancreas are identified as focal alteration in the size or contour of the gland. Obliteration of contiguous fat planes, areas of necrosis within the tumor, and secondary effects on the uninvolved parts of the pancreas and biliary tree can be identified. CBT has substantially reduced the need for pancreatic angiography, percutaneous transhepatic cholangiography, and endoscopic retrograde pancreatocholangiography at this medical center. Although a definitive comparison of ultrasound and CT has not yet been accomplished, initial experience indicates that a complementary rather than competitive relationship will develop between the two imaging methods. (orig.) 891 MG/orig. 892 MB [de

  5. Lymphadenopathy in celiac disease: computed tomographic observations

    International Nuclear Information System (INIS)

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

    1984-01-01

    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

  6. Computed tomographical evaluation of diabetic nephropathy

    International Nuclear Information System (INIS)

    Ubara, Yoshifumi; Hara, Shigeko; Arizono, Kenji; Katori, Hideyuki; Yamada, Akira; Mimura, Nobuhide; Hagura, Ryoko.

    1996-01-01

    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)

  7. Lymphadenopathy in celiac disease: computed tomographic observations

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Computed tomographic diagnosis of pulmonary nodules

    International Nuclear Information System (INIS)

    Onoue, Masataka

    1986-01-01

    One hundred and fifty-two pulmonary nodules (PNs) were examined by thin-section computed tomography (CT) and conventional tomography (tomography). In this study, 109 PNs were analyzed to assess tissue density by calculating the representative CT number (RCT no.) from a computer printout. For the primary malignancies, the mean RCT no. was 72 HU, with a standard deviation (SD) of 21 HU, and for metastases, it was 66 ± 19 HU. The RCT no. separating primary malignancy from benign lesions was 157 HU, the one including metastasis was 183 HU. In addition, dual-energy CT scan was performed to evaluate capability of diagnosing calcification in 35 PNs. Dual-energy CT scan had increased the reliability of CT diagnosis for PNs with RCT no. between 100 HU and 300 HU. The descriptive criteria of CT and tomography for 127 PNs were analyzed and statistical diagnoses by CT and tomography were compared with the results of their final diagnoses. CT and tomography had domonstrated similar sensitivities in the evaluation of primary malignancies; 86 % in CT and 90 % in tomography, and the same sensitivities (86 %) in diagnosing metastases. In evaluating benign PNs, CT was superior to tomography with capability to detect minimal calcification and fat density; the specificity was 80 % with CT, and 52 % with tomography (p < 0.025). Overall accuracy in the diagnosis for PNs was 82 % with CT, and 73 % with tomography, which was not different statistically. It can be concluded that CT is a reliable examination in the evaluation of PNs, and there is an advantage to the use of CT over tomography in diagnosing benign lesions. (author)

  9. Simultaneous tomographic reconstruction and segmentation with class priors

    DEFF Research Database (Denmark)

    Romanov, Mikhail; Dahl, Anders Bjorholm; Dong, Yiqiu

    2015-01-01

    are combined to produce a reconstruction that is identical to the segmentation. We consider instead a hybrid approach that simultaneously produces both a reconstructed image and segmentation. We incorporate priors about the desired classes of the segmentation through a Hidden Markov Measure Field Model, and we...

  10. Computed tomographic analysis of urinary calculi

    International Nuclear Information System (INIS)

    Naito, Akira; Ito, Katsuhide; Ito, Shouko

    1986-01-01

    Computed tomography (CT) was employed in an effort to analyze the chemical composition of urinary calculi. Twenty-three surgically removed calculi were scanned in a water bath (in vitro study). Forteen of them in the body were scanned (in vivo study). The calculi consisted of four types: mixed calcium oxalate and phosphate, mixed calcium carbonate and phosphate, magnesium ammonium phosphate, and uric acid. The in vitro study showed that the mean and maximum CT values of uric acid stones were significantly lower than those of the other three types of stones. This indicated that stones with less than 450 HU are composed of uric acid. In an in vivo study, CT did not help to differentiate the three types of urinary calculi, except for uric acid stones. Regarding the mean CT values, there was no correlation between in vitro and in vivo studies. An experiment with commercially available drugs showed that CT values of urinary calculi were not dependent upon the composition, but dependent upon the density of the calculi. (Namekawa, K.)

  11. Computed tomographic study of aged schizophrenic patients

    International Nuclear Information System (INIS)

    Seno, Haruo; Fujimoto, Akihiko; Ishino, Hiroshi; Shibata, Masahiro; Kuroda, Hiroyuki; Kanno, Hiroshi.

    1997-01-01

    The width of interhemispheric fissure, lateral ventricles and third ventricle were measured using cranial computed tomography (CT; linear method) in 45 elderly inpatients with chronic schizophrenia and in 28 age-matched control subjects. Twenty-three patients were men and 22 were women. In addition, Mini-Mental State Examination, Brief Psychiatric Rating Scale (BPRS) and a subclass of BPRS were undertaken in all patients. There is a significant enlargement of the maximum width of the interhemispheric fissure (in both male and female) and a significant enlargement of ventricular system (more severe in men than in women) in aged schizophrenics, as seen with CT, compared with normal controls. These findings are consistent with previous studies of non-aged schizophrenic patients. Based upon the relation between psychiatric symptoms and CT findings, the most striking is a significant negative correlation between the third ventricle enlargement and the positive and depressive symptoms in all patients. This result suggests that the advanced third ventricle enlargement may decrease these symptoms in aged schizophrenics. (author)

  12. Computed tomographic study on Mycoplasma pneumoniae pneumonia

    International Nuclear Information System (INIS)

    Tanaka, Hiroshi; Koba, Hiroyuki; Mori, Takuji; Mori, Masaki; Tsunematsu, Kazunori; Natori, Hiroshi; Asakawa, Mitsuo; Suzuki, Akira; Doi, Mikio.

    1985-01-01

    Serologically proven 21 patients with Mycoplasma pneumoniae pneumonia that showed infiltrative shadows on chest radiograms were studied by computed tomography (CT). Localization of the lesion and the fashion of its progression through the lung were analyzed. Following 3 loci were defined on the basis of the investigations of critical analysis of the chest radiograms, and of radiopathological analysis of the experimental animal model of mycoplasmal pneumonia with soft X-ray image. I: Peribronchial and periarterial interstitium. II: Bronchiole and its surroundings. III: Lung parenchyma, on hilar area as IIIh, on marginal area as IIIm. Even in the early phase of this disease, radiopathological findings on CT have been distributed in all loci mentioned above. The Shadow disappeared from locus III approximately 14th day from the onset. The shadow have remained, however, loci I, II for a long period. Those findings suggest that locus I and II are one of the major focus of Mycoplasma neumoniae pneumonia. Volume loss in the locus III was observed 78 % of the cases at 28th day from the onset. The shadow on locus IIIh was more prominent than locus IIIm. Reported analytical method with CT could be widely applied to disclose a radiopathological details in other infectious diseases of the lung. (author)

  13. ULTRASOUND AND COMPUTED TOMOGRAPHIC DIAGNOSIS OF OPTIC NERVE TUMORS

    Directory of Open Access Journals (Sweden)

    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.

  14. Computed Tomographic Measurement of Splenic Size in

    International Nuclear Information System (INIS)

    Sung, Nak Kwan; Woo, Seong Ku; Ko, Young Tae; Kim, Soon Young

    2010-01-01

    Authors analyzed 72 cases of abdominal computed tomography of Korean adults who didn't have any medical reasons to believe the spleen was abnormal. The following criteria were measured with multiple transverse scanning of the entire length of spleen (height, breadth, thickness) relationship with fixed midline structure, the spine (the shortest distance from midline to medial edge of spleen, the longest distance from anterior margin of vertebral body to anterior tip of spleen). The results were as follows: 1. The average size in adult was 8.0±1.5cm in height, 8.6±1.2cm in breadth and 3.4±0.6cm in thickness; in adult female, 7.8±1.1cm, 8.4±1.0cm and 3.4±0.6cm, respectively; total average, 7.9±1.3cm, 8.5±1.1cm and 3.4±0.6cm, respectively. No remarkable difference was noted between both sexes and age groups. 2. The shortest distance from midline to medial edge of spleen was 4.1±1.1cm in male, 3.6±1.0cm in female and total average of 3.9±1.1cm. There was remarkable difference between both sexes (P<0.005) but not between age groups. 3. The longest distance from anterior margin of vertebral body to anterior adge of spleen was 2.3±1.7cm in male, 2.0±1.4cm in female and total average of 2.2±1.6cm. No remarkable difference was seen between both sexes and age groups.

  15. Linogram and other direct Fourier methods for tomographic reconstruction

    International Nuclear Information System (INIS)

    Magnusson, M.

    1993-01-01

    Computed tomography (CT) is an outstanding break-through in technology as well as in medical diagnostics. The aim in CT is to produce an image with good image quality as fast as possible. The two most well-known methods for CT-reconstruction are the Direct Fourier Method (DFM) and the Filtered Backprojection Method (FBM). This thesis is divided in four parts. In part 1 we give an introduction to the principles of CT as well as a basic treatise of the DFM and the FBM. We also present a short CT history as well as brief descriptions of techniques related to X-ray CT such as SPECT, PET and MRI. Part 2 is devoted to the Linogram Method (LM). The method is presented both intuitively and rigorously and a complete algorithm is given for the discrete case. The implementation has been done using the SNARK subroutine package with various parameters and phantom images. For comparison, the FBM has been applied to the same input projection data. The experiments show that the LM gives almost the same image quality, pixel for pixel, as the FBM. In part 3 we show that the LM is a close relative to the common DFM. We give a new extended explanation of artifacts in DFMs. The source of the problem is twofold: interpolation errors and circular convolution. By identifying the second effect as distinct from the first one, we are able to suggest and verify remedies for the DFM which brings the image quality on par with FBM. One of these remedies is the LM. A slight difficulty with both LM and ordinary DFM techniques is that they require a special projection geometry, whereas most commercial CT-scanners provides fan beam projection data. However, the wanted linogram projection data can be interpolated from fan beam projection data. In part 4, we show that it is possible to obtain good image quality with both LM and DFM techniques using fan beam projection indata. The thesis concludes that the computation cost can be essentially decreased by using LM or other DFMs instead of FBM

  16. A computed tomographic study on epilepsy

    International Nuclear Information System (INIS)

    Bae, Hoon Sik

    1980-01-01

    140 patients with epileptic seizure were studied by computed tomography during the period from Feb. 1979 to Aug. 1979 in the Department or Radiology, College of Medicine, Hangyang University. Those findings on CT and clinical records including EEG findings were reviewed. The results were as follows: 1. Age distribution of the total 140 patients was broad ranging from 1 month to 63 years. 73.5% of patients was below the age of 30. The patient population was comprised of 93 males and 47 females, and its male to female ratio was 2 : 1. 2. The type of epileptic seizure were classified according to the International League against Epilepsy. 42.9% of patients had primary generalized seizure, 47.1% with partial seizure, and 10% with non classifiable seizure. 3. As additional symptoms and signs except seizure, headache was most common, and the next was nausea and vomiting. Uncommonly, there were also insomnia, personality change, and memory disturbance. 4. 37.1% of patients had less than 1 month of seizure history, 19.3% between 1 year and 5 years. 5. EEG findings were available in 41 patients, and normal in 15 cases. 26 patients revealed abnormal findings. Among those abnormal findings focal slowing was appeared in 19.5% and generalized slowing in 17.1%. 6. 52% of patients showed abnormal findings on CT. The most common abnormal findings was focal low density (30%), and the next was diffuse hydrocephalus (7.1%). After contrast infusion, contrast enhancement was occurred in cases with focal low density, focal high or isodense mass density. In patients with focal low density, ring or nodular enhancement were common, and diffuse or serpentime enhancement in focal high or isodence mass density. 7. The frequency of structural abnormalities on CT was more common in patients below the age of 10 and over 30 than other age groups. The epilepsy starting below 10 and over 30 years of age showed structural abnormalities in 63.6-100%. 8. The patients who had less than 6 months of

  17. A computed tomographic study on epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Hoon Sik [Hanyang University College of Medicine, Seoul (Korea, Republic of)

    1980-06-15

    140 patients with epileptic seizure were studied by computed tomography during the period from Feb. 1979 to Aug. 1979 in the Department or Radiology, College of Medicine, Hangyang University. Those findings on CT and clinical records including EEG findings were reviewed. The results were as follows: 1. Age distribution of the total 140 patients was broad ranging from 1 month to 63 years. 73.5% of patients was below the age of 30. The patient population was comprised of 93 males and 47 females, and its male to female ratio was 2 : 1. 2. The type of epileptic seizure were classified according to the International League against Epilepsy. 42.9% of patients had primary generalized seizure, 47.1% with partial seizure, and 10% with non classifiable seizure. 3. As additional symptoms and signs except seizure, headache was most common, and the next was nausea and vomiting. Uncommonly, there were also insomnia, personality change, and memory disturbance. 4. 37.1% of patients had less than 1 month of seizure history, 19.3% between 1 year and 5 years. 5. EEG findings were available in 41 patients, and normal in 15 cases. 26 patients revealed abnormal findings. Among those abnormal findings focal slowing was appeared in 19.5% and generalized slowing in 17.1%. 6. 52% of patients showed abnormal findings on CT. The most common abnormal findings was focal low density (30%), and the next was diffuse hydrocephalus (7.1%). After contrast infusion, contrast enhancement was occurred in cases with focal low density, focal high or isodense mass density. In patients with focal low density, ring or nodular enhancement were common, and diffuse or serpentime enhancement in focal high or isodence mass density. 7. The frequency of structural abnormalities on CT was more common in patients below the age of 10 and over 30 than other age groups. The epilepsy starting below 10 and over 30 years of age showed structural abnormalities in 63.6-100%. 8. The patients who had less than 6 months of

  18. Investigation of the noise effect on tomographic reconstructions for a tangentially viewing vacuum ultraviolet imaging diagnostic

    International Nuclear Information System (INIS)

    Ming, Tingfeng; Ohdachi, Satoshi; Suzuki, Yasuhiro

    2011-01-01

    Tomographic reconstruction for a tangentially viewing two-dimensional (2D) imaging system is studied. A method to calculate the geometry matrix in 2D tomography is introduced. An algorithm based on a Phillips-Tikhonov (P-T) type regularization method is investigated, and numerical tests using the P-T method are conducted with both tokamak and Heliotron configurations. The numerical tests show that the P-T method is not sensitive to the added noise levels and the emission profiles with higher mode numbers can be reconstructed with adequate resolution. The results indicate that this method is suitable for 2D tomographic reconstruction for a tangentially viewing vacuum ultraviolet telescope system. (author)

  19. Reconstruction of tomographic images from projections of a small number of views by means of mathematical programming

    International Nuclear Information System (INIS)

    Kobayashi, Fujio; Yamaguchi, Shoichiro

    1985-01-01

    Fundamental studies have been made on the application of mathematical programming to the reconstruction of tomographic images from projections of a small number of views without requiring any circular symmetry nor periodicity. Linear programming and quadratic programming were applied to minimize the quadratic sum of the residue and to finally obtain optimized reconstruction images. The mathematical algorithms were verified by the method of computer simulation, and the relationship between the number of picture elements and the number of iterations necessary for convergence was also investigated. The methods of linear programming and quadratic programming require fairly simple mathematical procedures, and strict solutions can be obtained within a finite number of iterations. Their only draw back is the requirement of a large quantity of computer memory. But this problem will be desolved by the advent of large fast memory devices in the near future. (Aoki, K.)

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

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  1. Investigating Gravity Waves in Polar Mesospheric Clouds Using Tomographic Reconstructions of AIM Satellite Imagery

    Science.gov (United States)

    Hart, V. P.; Taylor, M. J.; Doyle, T. E.; Zhao, Y.; Pautet, P.-D.; Carruth, B. L.; Rusch, D. W.; Russell, J. M.

    2018-01-01

    This research presents the first application of tomographic techniques for investigating gravity wave structures in polar mesospheric clouds (PMCs) imaged by the Cloud Imaging and Particle Size instrument on the NASA AIM satellite. Albedo data comprising consecutive PMC scenes were used to tomographically reconstruct a 3-D layer using the Partially Constrained Algebraic Reconstruction Technique algorithm and a previously developed "fanning" technique. For this pilot study, a large region (760 × 148 km) of the PMC layer (altitude 83 km) was sampled with a 2 km horizontal resolution, and an intensity weighted centroid technique was developed to create novel 2-D surface maps, characterizing the individual gravity waves as well as their altitude variability. Spectral analysis of seven selected wave events observed during the Northern Hemisphere 2007 PMC season exhibited dominant horizontal wavelengths of 60-90 km, consistent with previous studies. These tomographic analyses have enabled a broad range of new investigations. For example, a clear spatial anticorrelation was observed between the PMC albedo and wave-induced altitude changes, with higher-albedo structures aligning well with wave troughs, while low-intensity regions aligned with wave crests. This result appears to be consistent with current theories of PMC development in the mesopause region. This new tomographic imaging technique also provides valuable wave amplitude information enabling further mesospheric gravity wave investigations, including quantitative analysis of their hemispheric and interannual characteristics and variations.

  2. A tensor-based dictionary learning approach to tomographic image reconstruction

    DEFF Research Database (Denmark)

    Soltani, Sara; Kilmer, Misha E.; Hansen, Per Christian

    2016-01-01

    We consider tomographic reconstruction using priors in the form of a dictionary learned from training images. The reconstruction has two stages: first we construct a tensor dictionary prior from our training data, and then we pose the reconstruction problem in terms of recovering the expansion...... coefficients in that dictionary. Our approach differs from past approaches in that (a) we use a third-order tensor representation for our images and (b) we recast the reconstruction problem using the tensor formulation. The dictionary learning problem is presented as a non-negative tensor factorization problem...... with sparsity constraints. The reconstruction problem is formulated in a convex optimization framework by looking for a solution with a sparse representation in the tensor dictionary. Numerical results show that our tensor formulation leads to very sparse representations of both the training images...

  3. Tomographic apparatus and method for reconstructing planar slices from non-absorbed and non-scattered radiation

    International Nuclear Information System (INIS)

    1980-01-01

    An apparatus is described which can be used in computerized tomographic systems for constructing a representation of an object and which uses a fan-shaped beam source, detectors and a convolution method of data reconstruction. (U.K.)

  4. 3-dimensional charge collection efficiency measurements using volumetric tomographic reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Dobos, Daniel [CERN, Geneva (Switzerland)

    2016-07-01

    For a better understanding of the electrical field distribution of 3D semiconductor detectors and to allow efficiency based design improvements, a method to measure the 3D spatial charge collection efficiency of planar, 3D silicon and diamond sensors using 3D volumetric reconstruction techniques is possible. Simulation results and first measurements demonstrated the feasibility of this method and show that with soon available 10 times faster beam telescopes even small structures and efficiency differences will become measurable in few hours.

  5. First experience with a mobile computed tomograph in the USSR

    International Nuclear Information System (INIS)

    Portnoj, L.M.

    1989-01-01

    Utilization experience of mobile computerized tomograph mounted in the bus is presented. Problems concerning staff, selection of medical base institutes etc are considered. Efficiency of mobile computerized tomographes in revealing different diseases is pointed out

  6. Use of regularized algebraic methods in tomographic reconstruction

    International Nuclear Information System (INIS)

    Koulibaly, P.M.; Darcourt, J.; Blanc-Ferraud, L.; Migneco, O.; Barlaud, M.

    1997-01-01

    The algebraic methods are used in emission tomography to facilitate the compensation of attenuation and of Compton scattering. We have tested on a phantom the use of a regularization (a priori introduction of information), as well as the taking into account of spatial resolution variation with the depth (SRVD). Hence, we have compared the performances of the two methods by back-projection filtering (BPF) and of the two algebraic methods (AM) in terms of FWHM (by means of a point source), of the reduction of background noise (σ/m) on the homogeneous part of Jaszczak's phantom and of reconstruction speed (time unit = BPF). The BPF methods make use of a grade filter (maximal resolution, no noise treatment), single or associated with a Hann's low-pass (f c = 0.4), as well as of an attenuation correction. The AM which embody attenuation and scattering corrections are, on one side, the OS EM (Ordered Subsets, partitioning and rearranging of the projection matrix; Expectation Maximization) without regularization or SRVD correction, and, on the other side, the OS MAP EM (Maximum a posteriori), regularized and embodying the SRVD correction. A table is given containing for each used method (grade, Hann, OS EM and OS MAP EM) the values of FWHM, σ/m and time, respectively. One can observe that the OS MAP EM algebraic method allows ameliorating both the resolution, by taking into account the SRVD in the reconstruction process and noise treatment by regularization. In addition, due to the OS technique the reconstruction times are acceptable

  7. A maximum-likelihood reconstruction algorithm for tomographic gamma-ray nondestructive assay

    International Nuclear Information System (INIS)

    Prettyman, T.H.; Estep, R.J.; Cole, R.A.; Sheppard, G.A.

    1994-01-01

    A new tomographic reconstruction algorithm for nondestructive assay with high resolution gamma-ray spectroscopy (HRGS) is presented. The reconstruction problem is formulated using a maximum-likelihood approach in which the statistical structure of both the gross and continuum measurements used to determine the full-energy response in HRGS is precisely modeled. An accelerated expectation-maximization algorithm is used to determine the optimal solution. The algorithm is applied to safeguards and environmental assays of large samples (for example, 55-gal. drums) in which high continuum levels caused by Compton scattering are routinely encountered. Details of the implementation of the algorithm and a comparative study of the algorithm's performance are presented

  8. Computer tomographic and angiographic studies of histologically confirmed intrahepatic masses

    International Nuclear Information System (INIS)

    Janson, R.; Lackner, K.; Paquet, K.J.; Thelen, M.; Thurn, P.

    1980-01-01

    The computer tomographic and angiographic findings in 53 patients with intrahepatic masses were compared. The histological findings show that 17 were due to echinococcus, 12 were due to hepatic carcinoma, ten were metastases, five patients had focal nodular hyperplasia, three an alveolar echinococcus and there were three cases with an haemangioma of the liver and a further three liver abscesses. Computer tomography proved superior in peripherally situated lesions, and in those in the left lobe of the liver. Arteriography was better at demonstrating lesions below 2 cm in size, particularly vascular tumours. As a pre-operative measure, angiography is to be preferred since it is able to demonstrate anatomic anomalies and variations in the blood supply, as well as invasion of the portal vein or of the inferior vena cava. (orig.) [de

  9. Computer tomographic and angiographic studies of histologically confirmed intrahepatic masses

    Energy Technology Data Exchange (ETDEWEB)

    Janson, R.; Lackner, K.; Paquet, K.J.; Thelen, M.; Thurn, P.

    1980-06-01

    The computer tomographic and angiographic findings in 53 patients with intrahepatic masses were compared. The histological findings show that 17 were due to echinococcus, 12 were due to hepatic carcinoma, ten were metastases, five patients had focal nodular hyperplasia, three an alveolar echinococcus and there were three cases with an haemangioma of the liver and a further three liver abscesses. Computer tomography proved superior in peripherally situated lesions, and in those in the left lobe of the liver. Arteriography was better at demonstrating lesions below 2 cm in size, particularly vascular tumours. As a pre-operative measure, angiography is to be preferred since it is able to demonstrate anatomic anomalies and variations in the blood supply, as well as invasion of the portal vein or of the inferior vena cava.

  10. Alveolar echinococcosis of the liver - computed tomographic findings

    International Nuclear Information System (INIS)

    Merkle, E.; Usadel, S.; Vogel, J.; Kern, P.; Friedrich, J.M.; Brambs, H.J.

    1995-01-01

    In order to ascertain the typical computed tomographic findings of hepatic alveolar echinococcosis, 24 computed tomograms of 19 patients were evaluated. The liver was involved in all cases whereas the diaphragma was infiltrated in 32%, and the retroperioteneal area in 42%. The right liver lobe was affected in 65%. Both before and after intravenous bolus contrast medium administration, the lesions were mainly inhomogeneous and of low density; a masking of the lesions due to the contrast medium administration was not observed; the enhancement pattern was irregular. Calcifications were detected in 96% of the cases, cystic structures in 50%, and cholestasis in 54%. On the basis of the crucial finding of calcifications in combination with the other typical observations, CT seems to be very suitable for the evaluation of hepatic alveolar echinococcosis. (orig.) [de

  11. Spontaneous Intracerebral Hemorrhage: Computed Tomographic Characteristics and Outcome

    Directory of Open Access Journals (Sweden)

    Aimara de la Caridad Vergara Santos

    2015-12-01

    Full Text Available Background: strokes are the third leading cause of death among adults and 10-15 % of them are due to spontaneous intracerebral hemorrhage. Objective: to characterize spontaneous intracerebral hemorrhage through computed tomography scan and its outcome. Methods: a case series study was conducted comprising patients diagnosed with spontaneous intracerebral hemorrhage admitted to the Arnaldo Milián Castro Provincial University Hospital in Villa Clara from January 2009 to January 2010. Tomographic variables of interest were derived from evaluation of spontaneous intracerebral hematomas. Results: fifty-nine cases of spontaneous intracerebral hemorrhage were studied, 23 were located in lobar regions, 4 had severe midline shift, and 2 showed volume greater than 80 ml. Eight out of eleven with extension into the ventricular system had an unfavorable outcome. Among those with thalamic hemorrhage, patients with diameter larger than 4cm and extension into the ventricular system died. Patients with putaminal hemorrhage larger than 4 cm and posterior fossa hematoma with hydrocephalus had a poor outcome, as well as most individuals (55 with other mass effects. Most lobar hematomas (14 out of 23 had a satisfactory outcome, unlike cerebellar and brainstem hematomas. Conclusions: tomographic variables that had a negative impact on the outcome were: volume greater than 80 ml, severe midline shift, diameter larger than 4 cm, extension into the ventricular system, hydrocephalus, other signs of mass effect and brainstem location.

  12. Interpolation-free scanning and sampling scheme for tomographic reconstructions

    International Nuclear Information System (INIS)

    Donohue, K.D.; Saniie, J.

    1987-01-01

    In this paper a sampling scheme is developed for computer tomography (CT) systems that eliminates the need for interpolation. A set of projection angles along with their corresponding sampling rates are derived from the geometry of the Cartesian grid such that no interpolation is required to calculate the final image points for the display grid. A discussion is presented on the choice of an optimal set of projection angles that will maintain a resolution comparable to a sampling scheme of regular measurement geometry, while minimizing the computational load. The interpolation-free scanning and sampling (IFSS) scheme developed here is compared to a typical sampling scheme of regular measurement geometry through a computer simulation

  13. Application of the FDK algorithm for multi-slice tomographic image reconstruction; Aplicacao do algoritmo FDK para a reconstrucao de imagens tomograficas multicortes

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Paulo Roberto, E-mail: pcosta@if.usp.b [Universidade de Sao Paulo (IFUSP), SP (Brazil). Inst. de Fisica. Dept. de Fisica Nuclear; Araujo, Ericky Caldas de Almeida [Fine Image Technology, Sao Paulo, SP (Brazil)

    2010-08-15

    This work consisted on the study and application of the FDK (Feldkamp- Davis-Kress) algorithm for tomographic image reconstruction using cone-beam geometry, resulting on the implementation of an adapted multi-slice computed tomography system. For the acquisition of the projections, a rotating platform coupled to a goniometer, an X-ray equipment and a digital image detector charge-coupled device type were used. The FDK algorithm was implemented on a computer with a Pentium{sup R} XEON{sup TM} 3.0 processor, which was used for the reconstruction process. Initially, the original FDK algorithm was applied considering only the ideal physical conditions in the measurement process. Then some artifacts corrections related to the projections measurement process were incorporated. The implemented MSCT system was calibrated. A specially designed and manufactured object with a known linear attenuation coefficient distribution ({mu}(r)) was used for this purpose. Finally, the implemented MSCT system was used for multi-slice tomographic reconstruction of an inhomogeneous object, whose distribution {mu}(r) was unknown. Some aspects of the reconstructed images were analyzed to assess the robustness and reproducibility of the system. During the system calibration, a linear relationship between CT number and linear attenuation coefficients of materials was verified, which validate the application of the implemented multi-slice tomographic system for the characterization of linear attenuation coefficients of distinct several objects. (author)

  14. Direct iterative reconstruction of computed tomography trajectories (DIRECTT)

    International Nuclear Information System (INIS)

    Lange, A.; Hentschel, M.P.; Schors, J.

    2004-01-01

    The direct reconstruction approach employs an iterative procedure by selection of and angular averaging over projected trajectory data of volume elements. This avoids the blur effects of the classical Fourier method due to the sampling theorem. But longer computing time is required. The reconstructed tomographic images reveal at least the spatial resolution of the radiation detector. Any set of projection angles may be selected for the measurements. Limited rotation of the object yields still good reconstruction of details. Projections of a partial region of the object can be reconstructed without additional artifacts thus reducing the overall radiation dose. Noisy signal data from low dose irradiation have low impact on spatial resolution. The image quality is monitored during all iteration steps and is pre-selected according to the specific requirements. DIRECTT can be applied independently from the measurement equipment in addition to conventional reconstruction or as a refinement filter. (author)

  15. Clinical significance of computed tomographic arteriography for minute hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, H; Matsui, O; Suzuki, M; Ida, M; Kitagawa, K [Kanazawa Univ. (Japan). School of Medicine

    1982-03-01

    Computed tomographic arteriography (CTA) can clearly demonstrate minute hepatocellular carcinoma (H.C.C.) more than 2 cm in diameter as an enhanced mass lesion. In this case the precise localization of H.C.C. becomes so obvious that CTA plays an important role to evaluate its resectability. However, H.C.C. of the size from 2 cm to 1 cm indiameter, which is visualized with celiac and infusion hepatic angiography, becomes more difficult in detection, and particularly H.C.C. of less than 1 cm in diameter can hardly be recognized, nor be diagnosed as a malignant nodule by CTA, therefore it appears that in these sizes of H.C.C. the detectability of CTA is not superior to the hepatic angiography.

  16. Computed tomographic study of hormone-secreting microadenomas

    International Nuclear Information System (INIS)

    Hemminghytt, S.; Kalkhoff, R.K.; Daniels, D.L.; Williams, A.L.; Grogan, J.P.; Haughton, V.M.

    1983-01-01

    A review was made of the computed tomographic (CT) studies of 33 patients with hormone-secreting microadenomas that had been verified by transsphenoidal surgery and endocrinologic evaluation. In previous studies in small series of patients, the CT appearance of pituitary microadenomas has been reported as hypodense, isodense, and hyperdense. In this study, CT showed a region of diminished enhancement and ususally an enlarged pituitary gland in cases of prolactin-secreting adenomas. HGH- or ACTH-secreting adenomas were less consistently hypodense. It is concluded that hypodensity and enlargement in the pituitary gland are the most useful criteria for identification of microadenomas. Some technical factors that may affect the CT appearance of microadenomas and lead to conflicting reports are discussed

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

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  18. Computed tomographic findings in children with spastic diplegia

    International Nuclear Information System (INIS)

    Yokochi, Kenji; Horie, Masayo; Inukai, Kazuhisa; Kito, Hideyuki; Shimabukuro, Satoshi; Kodama, Kazuo.

    1989-01-01

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

  19. An evolutionary algorithm for tomographic reconstructions in limited data sets problems

    International Nuclear Information System (INIS)

    Turcanu, Catrinel; Craciunescu, Teddy

    2000-01-01

    The paper proposes a new method for tomographic reconstructions. Unlike nuclear medicine applications, in physical science problems we are often confronted with limited data sets: constraints in the number of projections or limited angle views. The problem of image reconstruction from projections may be considered as a problem of finding an image (solution) having projections that match the experimental ones. In our approach, we choose a statistical correlation coefficient to evaluate the fitness of any potential solution. The optimization process is carried out by an evolutionary algorithm. Our algorithm has some problem-oriented characteristics. One of them is that a chromosome, representing a potential solution, is not linear but coded as a matrix of pixels corresponding to a two-dimensional image. This kind of internal representation reflects the genuine manifestation and slight differences between two points situated in the original problem space give rise to similar differences once they become coded. Another particular feature is a newly built crossover operator: the grid-based crossover, suitable for high dimension two-dimensional chromosomes. Except for the population size and the dimension of the cutting grid for the grid-based crossover, all the other parameters of the algorithm are independent of the geometry of the tomographic reconstruction. The performances of the method are evaluated in comparison with a traditional tomographic method, based on the maximization of the entropy of the image, that proved to work well with limited data sets. The test phantom is typical for an application with limited data sets: the determination of the neutron energy spectra with time resolution in case of short-pulsed neutron emission. The qualitative judgement and also the quantitative one, based on some figures of merit, point out that the proposed method ensures an improved reconstruction of shapes, sizes and resolution in the image, even in the presence of noise

  20. Computed laminography and reconstruction algorithm

    International Nuclear Information System (INIS)

    Que Jiemin; Cao Daquan; Zhao Wei; Tang Xiao

    2012-01-01

    Computed laminography (CL) is an alternative to computed tomography if large objects are to be inspected with high resolution. This is especially true for planar objects. In this paper, we set up a new scanning geometry for CL, and study the algebraic reconstruction technique (ART) for CL imaging. We compare the results of ART with variant weighted functions by computer simulation with a digital phantom. It proves that ART algorithm is a good choice for the CL system. (authors)

  1. Tomographic image reconstruction using x-ray phase information

    Science.gov (United States)

    Momose, Atsushi; Takeda, Tohoru; Itai, Yuji; Hirano, Keiichi

    1996-04-01

    We have been developing phase-contrast x-ray computed tomography (CT) to make possible the observation of biological soft tissues without contrast enhancement. Phase-contrast x-ray CT requires for its input data the x-ray phase-shift distributions or phase-mapping images caused by an object. These were measured with newly developed fringe-scanning x-ray interferometry. Phase-mapping images at different projection directions were obtained by rotating the object in an x-ray interferometer, and were processed with a standard CT algorithm. A phase-contrast x-ray CT image of a nonstained cancerous tissue was obtained using 17.7 keV synchrotron x rays with 12 micrometer voxel size, although the size of the observation area was at most 5 mm. The cancerous lesions were readily distinguishable from normal tissues. Moreover, fine structures corresponding to cancerous degeneration and fibrous tissues were clearly depicted. It is estimated that the present system is sensitive down to a density deviation of 4 mg/cm3.

  2. Simulating multi-spacecraft Heliospheric Imager observations for tomographic reconstruction of interplanetary CMEs

    Science.gov (United States)

    Barnes, D.

    2017-12-01

    The multiple, spatially separated vantage points afforded by the STEREO and SOHO missions provide physicists with a means to infer the three-dimensional structure of the solar corona via tomographic imaging. The reconstruction process combines these multiple projections of the optically thin plasma to constrain its three-dimensional density structure and has been successfully applied to the low corona using the STEREO and SOHO coronagraphs. However, the technique is also possible at larger, inter-planetary distances using wide-angle imagers, such as the STEREO Heliospheric Imagers (HIs), to observe faint solar wind plasma and Coronal Mass Ejections (CMEs). Limited small-scale structure may be inferred from only three, or fewer, viewpoints and the work presented here is done so with the aim of establishing techniques for observing CMEs with upcoming and future HI-like technology. We use simulated solar wind densities to compute realistic white-light HI observations, with which we explore the requirements of such instruments for determining solar wind plasma density structure via tomography. We exploit this information to investigate the optimal orbital characteristics, such as spacecraft number, separation, inclination and eccentricity, necessary to perform the technique with HIs. Further to this we argue that tomography may be greatly enhanced by means of improved instrumentation; specifically, the use of wide-angle imagers capable of measuring polarised light. This work has obvious space weather applications, serving as a demonstration for potential future missions (such as at L1 and L5) and will prove timely in fully exploiting the science return from the upcoming Solar Orbiter and Parker Solar Probe missions.

  3. Tomographs based on non-conventional radiation sources and methods

    International Nuclear Information System (INIS)

    Barbuzza, R.; Fresno, M. del; Venere, Marcelo J.; Clausse, Alejandro; Moreno, C.

    2000-01-01

    Computer techniques for tomographic reconstruction of objects X-rayed with a compact plasma focus (PF) are presented. The implemented reconstruction algorithms are based on stochastic searching of solutions of Radon equation, using Genetic Algorithms and Monte Carlo methods. Numerical experiments using actual projections were performed concluding the feasibility of the application of both methods in tomographic reconstruction problem. (author)

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

    DEFF Research Database (Denmark)

    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 compli......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...... be kept in mind, especially inthe patients with peripheral vascular disease. 3D-MSCTA has the potential to replace digital subtraction angiography for planning of microvascular reconstructions and newer devices with higher resolutions will probably increase the reliability of this technique. (c) 2009...

  5. Simulation of Tomographic Reconstruction of Magnetosphere Plasma Distribution By Multi-spacecraft Systems.

    Science.gov (United States)

    Kunitsyn, V.; Nesterov, I.; Andreeva, E.; Zelenyi, L.; Veselov, M.; Galperin, Y.; Buchner, J.

    A satellite radiotomography method for electron density distributions was recently proposed for closely-space multi-spacecraft group of high-altitude satellites to study the physics of reconnection process. The original idea of the ROY project is to use a constellation of spacecrafts (one main and several sub-satellites) in order to carry out closely-spaced multipoint measurements and 2D tomographic reconstruction of elec- tron density in the space between the main satellite and the subsatellites. The distances between the satellites were chosen to vary from dozens to few hundreds of kilometers. The easiest data interpretation is achieved when the subsatellites are placed along the plasma streamline. Then, whenever a plasma density irregularity moves between the main satellite and the subsatellites it will be scanned in different directions and we can get 2D distribution of plasma using these projections. However in general sub- satellites are not placed exactly along the plasma streamline. The method of plasma velocity determination relative to multi-spacecraft systems is considered. Possibilities of 3D tomographic imaging using multi-spacecraft systems are analyzed. The model- ing has shown that efficient scheme for 3D tomographic imaging would be to place spacecrafts in different planes so that the angle between the planes would make not more then ten degrees. Work is supported by INTAS PROJECT 2000-465.

  6. Diagnostic accuracy of multi-slice computed tomographic angiography in the detection of cerebral aneurysms

    International Nuclear Information System (INIS)

    Haghighatkhah, H. R.; Sabouri, S.; Borzouyeh, F.; Bagherzadeh, M. H.; Bakhshandeh, H.; Jalali, A. H.

    2008-01-01

    Multislice computed tomographic angiography is a rapid and minimally invasive method for the detection of intracranial aneurysms. The purpose of this study was to compare Multislice computed tomographic angiography with digital subtraction angiography In the diagnosis of cerebral aneurysms. Patients and Methods: In this cross sectional study we evaluated 111 consecutive patients [42(37.8%) male and 69(62.2%) female], who were admitted under clinical symptoms and signs. suggestive of harboring an intracranial aneurysm by using a four detector Multislice computed tomographic angiography. Then we compared results of Multislice computed tomographic angiography with digital subtraction angiography results as a gold standard method. Digital subtraction angiography was performed by bilateral selective common carotid artery injections and either unilateral or bilateral vertebral artery injections, as necessary. Multislice computed tomographic angiography images were interpreted by one radiologist and digital subtraction angiography was performed by another radiologist who was blinded to the interpretation of the Multislice computed tomographic angiograms. Results: The mean ±S D age of the patients was 49.1±13.6 years (range: 12-84 years). We performed Multislice computed tomographic in 111 and digital subtraction angiography in 85 patients. The sensitivity, specificity, positive predictive value, negative predictive value, positive and negative likelihood ratio of Multislice computed tomographic angiography, when compared with digital subtraction angiography as the gold standard, were 100%, 90%, 87.5%, 100%, 10 and 0, respectively. Conclusion: Multislice computed tomographic angiography seems to be an accurate and noninvasive imaging modality in the diagnosis of intracranial aneurysms

  7. Double Colorectal Cancer Only Diagnosed by Computed Tomographic Colonography

    Directory of Open Access Journals (Sweden)

    Koichi Nagata

    2008-02-01

    Full Text Available A 58-year-old woman presented to her physician with rectal bleeding and intermittent diarrhea. Optical colonoscopy revealed a bulky tumor which was diagnosed as rectal cancer. She was referred to our institution for further evaluation and treatment. Slim optical colonoscopy showed an obstructive cancer in the rectosigmoid junction and no information of the proximal side of the obstruction. The patient then underwent computed tomographic (CT colonography for further evaluation of the proximal side. Three-dimensional endoluminal ‘fly-through’ images revealed another protruded lesion in the proximal side of the obstruction. Diagnosis of synchronous double cancer was made by CT colonography. This CT data was not only used to create three-dimensional images but also to decide on a preoperative clinical staging. Laparoscopy-assisted high anterior resection was performed and T3 rectal cancer and T1 sigmoid colon cancer were confirmed in the resected specimen. Follow-up optical colonoscopy revealed no other tumors. CT colonography has recently become a popular preoperative examination tool with significant improvement in quality of image due to a rapid progress in computer technology. CT colonography correctly showed synchronous double cancer in our case and provided crucial information for planning surgery. We recommend that CT colonography should be used for evaluating the proximal side of obstructive colorectal cancer.

  8. On the computed tomographic diagnosis of pulmonary nodules

    International Nuclear Information System (INIS)

    Higashi, Yuuichirou

    1988-01-01

    Computed tomography (CT) was used to examine 53 pulmonary nodules which were considered not definitely calcified on plain radiographs or conventional tomograms. An average CT number was calculate for each lesion. For the primary lung cancers, the average CT number was 36 HU with a standard deviation of 6.6 HU, while the benign lesions had the mean CT number of 69 HU, with a standard deviation of 42.8 HU. The mean CT number separating lung malignancies from benign lesions was 78.8 HU. To evaluate the attenuation values within each nodule, iso-CT value map was obtained by using Siemens therapy planning system, MEVAPLAN. Nodules were classified into five categories, Type I to V. All of three nodules classified as Type IV were benign. Iso-CT value map was effective in establishing the benignancy of nodules. The quantitative computed tomographic analysis of pulmonary nodules was evaluated by dual-energy CT. Dual-energy CT has the potential to eliminate the effect of spectral hardening by use of monoenergic images derived from dual-kV data and to separate high CT numbers due to calcium from those due to high density organic material. (author)

  9. GPU acceleration towards real-time image reconstruction in 3D tomographic diffractive microscopy

    Science.gov (United States)

    Bailleul, J.; Simon, B.; Debailleul, M.; Liu, H.; Haeberlé, O.

    2012-06-01

    Phase microscopy techniques regained interest in allowing for the observation of unprepared specimens with excellent temporal resolution. Tomographic diffractive microscopy is an extension of holographic microscopy which permits 3D observations with a finer resolution than incoherent light microscopes. Specimens are imaged by a series of 2D holograms: their accumulation progressively fills the range of frequencies of the specimen in Fourier space. A 3D inverse FFT eventually provides a spatial image of the specimen. Consequently, acquisition then reconstruction are mandatory to produce an image that could prelude real-time control of the observed specimen. The MIPS Laboratory has built a tomographic diffractive microscope with an unsurpassed 130nm resolution but a low imaging speed - no less than one minute. Afterwards, a high-end PC reconstructs the 3D image in 20 seconds. We now expect an interactive system providing preview images during the acquisition for monitoring purposes. We first present a prototype implementing this solution on CPU: acquisition and reconstruction are tied in a producer-consumer scheme, sharing common data into CPU memory. Then we present a prototype dispatching some reconstruction tasks to GPU in order to take advantage of SIMDparallelization for FFT and higher bandwidth for filtering operations. The CPU scheme takes 6 seconds for a 3D image update while the GPU scheme can go down to 2 or > 1 seconds depending on the GPU class. This opens opportunities for 4D imaging of living organisms or crystallization processes. We also consider the relevance of GPU for 3D image interaction in our specific conditions.

  10. Tuberculosis of the Parotid Gland: Computed Tomographic Findings

    International Nuclear Information System (INIS)

    Wei, Y.; Xiao, J.; Pui, M.H.; Gong, Q.

    2008-01-01

    Background: Tuberculosis (TB) of the parotid gland is rare, even in endemic regions. Approximately 100 cases have been reported in the English literature. The computed tomographic (CT) features, however, have seldom been studied. Purpose: To determine the diagnostic CT features of tuberculosis of the parotid gland. Material and Methods: CT studies of four histologically proven cases of tuberculosis of the parotid gland were retrospectively reviewed. Results: A total of 15 enlarged lymph nodes were found in the superficial lobes of the parotid glands. The nodes were arranged linearly within the gland. Enhancement patterns included homogeneous enhancement (9/15, 60%), homogeneous enhancement with eccentric microcysts (3/15, 20%), and thick-walled rim enhancement with central lucency (3/15, 20%). Thickened adjacent fascial plane and platysma were seen in two patients. Ipsilateral cervical lymphadenopathy was seen in all patients. Conclusion: In patients presenting with unilateral parotid nodules, TB should be considered when linearly arranged enhancing nodules are demonstrated in the superficial lobes of the glands on CT scan

  11. Brain computed tomographic findings in post-cardiopulmonary resuscitation patients

    International Nuclear Information System (INIS)

    Ishida, Tsuguharu; Yoshinaga, Kazumasa; Horibe, Takashi; Kokubu, Kiyokazu; Kokura, Yoshihiro; Matsui, Konosuke; Inamoto, Kazuo.

    1986-01-01

    We retrospectively assessed the brain computed tomographic (CT) findings in 22 post-cardiopulmonary resuscitation (CPR) patients excluding neonatal cases. On the basis of the CT findings, the patients were divided into two groups. Eight patients (36.4 %) had bilateral abnormal lowdensity areas in the basal ganglia (Group I). The remaining 14 patients (63.6 %) had no abnormalities in that area (Group II). In Group I, the incidence of primary cardiac arrest and duration of advanced life support (ALS) was significantly different (p < 0.05) from Group II. Sex, age, duration of basic life support (BLS), time elapsed from initiation of BLS to initial CT and from initiation of ALS to initial CT was not significantly different between the two groups. Outcome was very poor in both groups and no significant difference was noted between them. We conclude that primary cardiac arrest and long duration of ALS were predictors of abnormal bilateral low-density areas in the basal ganglia in post-CPR patients. However, their appearance was not related to outcome. (author)

  12. Computed tomographic findings of liver injury in adults

    International Nuclear Information System (INIS)

    Ha, Deok Gi; Lee, Hyeon Kyeong; Lee, Won Jae; Oh, Yeon Hee; Lee, Sung Hee; Yun, Jee Yeong; Lee, Tae Woo; Lee, Sung Woo; Park, Soo Soung

    1994-01-01

    We studied to compare computed tomographic(CT) findings of liver injury with management method in adults and, moreover, to present the CT basis for the management. We retrospectively reviewed CT scans of 43 adults diagnosed as liver injury during a 66 month period. Thirty-eight patients were hemodynamically stable. Thirty-two of them were managed conservatively, whereas six managed operatively. Five unstable patients underwent emergency operation. We classified CT findings according to the severity of liver injuries(ie, hematoma, laceration, and periportal tracking) and hemoperitoneum, ranging from grade 1 to 5 and from 0 to 3 +. respectively. Thus, we compared the CT classifications with their management(ie, operation rate), especially hemodynamically stable patients. Operation rates of all patients and hemodynamically stable patients were 26% and 16%, respectively. Operation rate at each grade of liver injury was low, especially in hemodynamically stable, despite relatively high operation rate in grade 4. Operation rate of 3+ homoperitoneum was 100%, including hemodynamically stable patients, in contrast to otherwise low operation rate of others. Most liver injury in adults, including grade 4, were managed conservatively, especially hemodynamically stable. Though large amount of hemoperitoneum(ie, 3+) required operation, most hemooperitoeum were managed conservatively. Thus, CT findings of liver injury is helpful in the decision for the management method

  13. Computed tomographic mammography using a conventional body scanner.

    Science.gov (United States)

    Chang, C H; Nesbit, D E; Fisher, D R; Fritz, S L; Dwyer, S J; Templeton, A W; Lin, F; Jewell, W R

    1982-03-01

    The technique for computed tomographic (CT) examination of the breasts using a conventional body scanner is described, and experience with 67 patients is reported. In the diagnosis of both malignant and benign breast lesions, the results with a body scanner were equal to those of a dedicated CT/M mammographic unit. Although the CT study of the breast cannot replace conventional mammography in screening or in routine diagnostic workup, the unique capability of demonstrating both anatomic changes and increased iodide concentration in a cancer provides many advantages over conventional mammography. CT mammography appears to have the capability to detect breast cancers that are occult to other methods. Indications for a CT study of the breasts are: (1) clinically suspected breast cancer, especially with a mammographically occult lesion; (2) questionable mammographic findings, including microcalcifications, tumor shape, architectural distortion, and uncertain lesion location; and (3) evaluation of postbiopsy or postlumpectomy breast cancers when a primary irradiation therapy is contemplated. Breast CT also appears to be a valuable diagnostic tool in searching for a second primary breast cancer, follow-up study of postirradiation of breast cancer, followup study for postmastectomy patients, and screening procedure for genetically high-risk patients, especially those with dense breasts.

  14. The robustness of two tomography reconstructing techniques with heavily noisy dynamical experimental data from a high speed gamma-ray tomograph

    International Nuclear Information System (INIS)

    Vasconcelos, Geovane Vitor; Melo, Silvio de Barros; Dantas, Carlos Costa; Moreira, Icaro Malta; Johansen, Geira; Maad, Rachid

    2013-01-01

    The PSIRT (Particle Systems Iterative Reconstructive Technique) is, just like the ART method, an iterative tomographic reconstruction technique with the recommended use in the reconstruction of catalytic density distribution in the refining process of oil in the FCC-type riser. The PSIRT is based upon computer graphics' particle systems, where the reconstructing material is initially represented as composed of particles subject to a force field emanating from the beams, whose intensities are parameterized by the differences between the experimental readings of a given beam trajectory, and the values corresponding to the current amount of particles landed in this trajectory. A dynamical process is set as the beams fields of attracting forces dispute the particles. At the end, with the equilibrium established, the particles are replaced by the corresponding regions of pixels. The High Speed Gamma-ray Tomograph is a 5-source-fan-beam device with a 17-detector deck per source, capable of producing up to a thousand complete sinograms per second. Around 70.000 experimental sinograms from this tomograph were produced simulating the move of gas bubbles in different angular speeds immersed in oil within the vessel, through the use of a two-hole-polypropylene phantom. The sinogram frames were set with several different detector integration times. This article studies and compares the robustness of both ART and PSIRT methods in this heavily noisy scenario, where this noise comes not only from limitations in the dynamical sampling, but also from to the underlying apparatus that produces the counting in the tomograph. These experiments suggest that PSIRT is a more robust method than ART for noisy data. Visual inspection on the resulting images suggests that PSIRT is a more robust method than ART for noisy data, since it almost never presents globally scattered noise. (author)

  15. Blunt oesophageal perforation: treatment with surgical exclusion and percutaneous drainage under computed tomographic guidance

    International Nuclear Information System (INIS)

    Vauthey, J.N.; Lerut, J.; Laube, M.; Gertsch, P.

    1992-01-01

    We report a patient with a left thoracic contusion and rupture of the distal oesophagus. Persistent sepsis developed after oesophageal exclusion without closure. Two collection were drained percutaneously under computed tomographic guidance and the sepsis resolved. (11 refs., 1 fig.)

  16. Data-parallel tomographic reconstruction : A comparison of filtered backprojection and direct Fourier reconstruction

    NARCIS (Netherlands)

    Roerdink, J.B.T.M.; Westenberg, M.A

    1998-01-01

    We consider the parallelization of two standard 2D reconstruction algorithms, filtered backprojection and direct Fourier reconstruction, using the data-parallel programming style. The algorithms are implemented on a Connection Machine CM-5 with 16 processors and a peak performance of 2 Gflop/s.

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

    International Nuclear Information System (INIS)

    Jeong, Ho Gul; Kim, Kee Deog; Shin, Dong Won; Hu, Kyung Seok; Lee, Jae Bum; Park, Hyok; Park, Chang Seo; Han, Seung Ho

    2006-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. A high-throughput system for high-quality tomographic reconstruction of large datasets at Diamond Light Source.

    Science.gov (United States)

    Atwood, Robert C; Bodey, Andrew J; Price, Stephen W T; Basham, Mark; Drakopoulos, Michael

    2015-06-13

    Tomographic datasets collected at synchrotrons are becoming very large and complex, and, therefore, need to be managed efficiently. Raw images may have high pixel counts, and each pixel can be multidimensional and associated with additional data such as those derived from spectroscopy. In time-resolved studies, hundreds of tomographic datasets can be collected in sequence, yielding terabytes of data. Users of tomographic beamlines are drawn from various scientific disciplines, and many are keen to use tomographic reconstruction software that does not require a deep understanding of reconstruction principles. We have developed Savu, a reconstruction pipeline that enables users to rapidly reconstruct data to consistently create high-quality results. Savu is designed to work in an 'orthogonal' fashion, meaning that data can be converted between projection and sinogram space throughout the processing workflow as required. The Savu pipeline is modular and allows processing strategies to be optimized for users' purposes. In addition to the reconstruction algorithms themselves, it can include modules for identification of experimental problems, artefact correction, general image processing and data quality assessment. Savu is open source, open licensed and 'facility-independent': it can run on standard cluster infrastructure at any institution.

  20. Statistical list-mode image reconstruction for the high resolution research tomograph

    International Nuclear Information System (INIS)

    Rahmim, A; Lenox, M; Reader, A J; Michel, C; Burbar, Z; Ruth, T J; Sossi, V

    2004-01-01

    We have investigated statistical list-mode reconstruction applicable to a depth-encoding high resolution research tomograph. An image non-negativity constraint has been employed in the reconstructions and is shown to effectively remove the overestimation bias introduced by the sinogram non-negativity constraint. We have furthermore implemented a convergent subsetized (CS) list-mode reconstruction algorithm, based on previous work (Hsiao et al 2002 Conf. Rec. SPIE Med. Imaging 4684 10-19; Hsiao et al 2002 Conf. Rec. IEEE Int. Symp. Biomed. Imaging 409-12) on convergent histogram OSEM reconstruction. We have demonstrated that the first step of the convergent algorithm is exactly equivalent (unlike the histogram-mode case) to the regular subsetized list-mode EM algorithm, while the second and final step takes the form of additive updates in image space. We have shown that in terms of contrast, noise as well as FWHM width behaviour, the CS algorithm is robust and does not result in limit cycles. A hybrid algorithm based on the ordinary and the convergent algorithms is also proposed, and is shown to combine the advantages of the two algorithms (i.e. it is able to reach a higher image quality in fewer iterations while maintaining the convergent behaviour), making the hybrid approach a good alternative to the ordinary subsetized list-mode EM algorithm

  1. Tomographic reconstruction of atmospheric volumes from infrared limb-imager measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ungermann, Joern

    2011-08-12

    State-of-the art nadir and limb-sounders, but also in situ measurements, do not offer the capability to highly resolve the atmosphere in all three dimensions. This leaves an observational gap with respect to small-scale structures that arise frequently in the atmosphere and that still lack a quantitative understanding. For instance, filaments and tropopause folds in the upper troposphere and lower stratosphere (UTLS) are crucial for its composition and variability. One way to achieve a highly resolved three-dimensional (3-D) picture of the atmosphere is the tomographic evaluation of limb-imager measurements. This thesis presents a methodology for the tomographic reconstruction of atmospheric constituents. To be able to deal with the large increase of observations and unknowns compared to conventional retrievals, great care is taken to reduce memory consumption and processing time. This method is used to evaluate the performance of two upcoming infrared limb-imager instruments and to prepare their missions. The first examined instrument is the infrared limb-imager on board of PREMIER (Process Exploration through Measurements of Infrared and millimetrewave Emitted Radiation), one of three remaining candidates for ESA's 7th Earth Explorer mission. Scientific goals of PREMIER are, among others, the examination of gravity waves and the quantification of processes controlling atmospheric composition in the UTLS, a region of particular importance for climate change. Simulations based on the performance requirements of this instrument deliver a vertical resolution that is slightly better than its vertical field-of-view (about 0.75 km) and a horizontal resolution of {approx}25km x 70 km. Non-linear end-to-end simulations for various gravity wave patterns demonstrate that the high 3-D resolution of PREMIER considerably extends the range of detectable gravity waves in terms of horizontal and vertical wavelength compared to previous observations. The second examined

  2. Tomographic reconstruction of atmospheric volumes from infrared limb-imager measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ungermann, Joern

    2011-08-12

    State-of-the art nadir and limb-sounders, but also in situ measurements, do not offer the capability to highly resolve the atmosphere in all three dimensions. This leaves an observational gap with respect to small-scale structures that arise frequently in the atmosphere and that still lack a quantitative understanding. For instance, filaments and tropopause folds in the upper troposphere and lower stratosphere (UTLS) are crucial for its composition and variability. One way to achieve a highly resolved three-dimensional (3-D) picture of the atmosphere is the tomographic evaluation of limb-imager measurements. This thesis presents a methodology for the tomographic reconstruction of atmospheric constituents. To be able to deal with the large increase of observations and unknowns compared to conventional retrievals, great care is taken to reduce memory consumption and processing time. This method is used to evaluate the performance of two upcoming infrared limb-imager instruments and to prepare their missions. The first examined instrument is the infrared limb-imager on board of PREMIER (Process Exploration through Measurements of Infrared and millimetrewave Emitted Radiation), one of three remaining candidates for ESA's 7th Earth Explorer mission. Scientific goals of PREMIER are, among others, the examination of gravity waves and the quantification of processes controlling atmospheric composition in the UTLS, a region of particular importance for climate change. Simulations based on the performance requirements of this instrument deliver a vertical resolution that is slightly better than its vertical field-of-view (about 0.75 km) and a horizontal resolution of {approx}25km x 70 km. Non-linear end-to-end simulations for various gravity wave patterns demonstrate that the high 3-D resolution of PREMIER considerably extends the range of detectable gravity waves in terms of horizontal and vertical wavelength compared to previous observations. The second examined instrument

  3. Regrowth patterns of supratentorial gliomas: estimation from computed tomographic scans

    Energy Technology Data Exchange (ETDEWEB)

    Tsuboi, K.; Yoshii, Y.; Nakagawa, K.; Maki, Y.

    1986-12-01

    To clarify the regrowth patterns of benign and malignant gliomas, we chose 27 intervals (between two operations or between an operation and autopsy) from 21 patients with pathologically verified recurrent supratentorial gliomas. Serial computed tomographic (CT) scans of these cases were analyzed to determine the doubling time (Td) calculated from the change in volume of enhanced and low density areas, the enhancement effect graded from 0 to 4 according to the Hounsfield number, and the presence of dissemination and contralateral extension. We studied 5 benign gliomas (including 1 case of radiation necrosis), 8 malignant astrocytomas, and 8 glioblastomas. The Td's of enhanced areas on CT scans of benign gliomas, malignant astrocytomas, and glioblastomas were 937 +/- 66.5 days, 65.1 +/- 29.4 days, and 48.1 +/- 20.9 days, respectively. The Td's of low density areas were 895 +/- 130.6 days, 70.8 +/- 22.2 days, and 50.5 +/- 14.7 days. There was a significant correlation between the Td's of the enhanced and low density areas (0.97). The enhancement effect increased at recurrence in 55% of the cases, with an average increase of 1.1 grades. The increase in enhancement effect at recurrence showed a tendency to become smaller as the tumor's degree of anaplasia increased. Radiotherapy was effective in significantly retarding the growth rate of malignant gliomas, whose Td's were doubled. Although the Td's of both enhanced and low density areas of benign gliomas were significantly longer than those of malignant gliomas, there was no significant difference in the Td's of enhanced areas between malignant astrocytomas and glioblastomas.

  4. Regrowth patterns of supratentorial gliomas: estimation from computed tomographic scans

    International Nuclear Information System (INIS)

    Tsuboi, K.; Yoshii, Y.; Nakagawa, K.; Maki, Y.

    1986-01-01

    To clarify the regrowth patterns of benign and malignant gliomas, we chose 27 intervals (between two operations or between an operation and autopsy) from 21 patients with pathologically verified recurrent supratentorial gliomas. Serial computed tomographic (CT) scans of these cases were analyzed to determine the doubling time (Td) calculated from the change in volume of enhanced and low density areas, the enhancement effect graded from 0 to 4 according to the Hounsfield number, and the presence of dissemination and contralateral extension. We studied 5 benign gliomas (including 1 case of radiation necrosis), 8 malignant astrocytomas, and 8 glioblastomas. The Td's of enhanced areas on CT scans of benign gliomas, malignant astrocytomas, and glioblastomas were 937 +/- 66.5 days, 65.1 +/- 29.4 days, and 48.1 +/- 20.9 days, respectively. The Td's of low density areas were 895 +/- 130.6 days, 70.8 +/- 22.2 days, and 50.5 +/- 14.7 days. There was a significant correlation between the Td's of the enhanced and low density areas (0.97). The enhancement effect increased at recurrence in 55% of the cases, with an average increase of 1.1 grades. The increase in enhancement effect at recurrence showed a tendency to become smaller as the tumor's degree of anaplasia increased. Radiotherapy was effective in significantly retarding the growth rate of malignant gliomas, whose Td's were doubled. Although the Td's of both enhanced and low density areas of benign gliomas were significantly longer than those of malignant gliomas, there was no significant difference in the Td's of enhanced areas between malignant astrocytomas and glioblastomas

  5. Microdose computed tomographic cardiac angiography in normal cats.

    Science.gov (United States)

    Rodriguez, Kiira T; O'Brien, Mauria A; Hartman, Susan K; Mulherin, Allison C; McReynolds, Casie J; McMichael, Maureen; Rapoport, Gregg; O'Brien, Robert T

    2014-03-01

    To determine if microdose contrast-enhanced multi-detector computed tomographic angiography (MDCTA) allows characterization of cardiac chambers in lightly sedated normal cats. Seven healthy domestic cats. Lightly sedated normal cats were imaged pre-contrast and with microdose (0.22 ml/kg of non-ionic iodinated contrast medium, 300 mg I/ml) triple-phase MDCTA in a motion restriction device. On pre-contrast images, the aorta (median: 52.43 Hounsfield units [HU], range 27.35-76.74 HU) was outlined by significantly (p = 0.015) lower attenuating periaortic fat (-66.16 HU, -42.62 to -92.77 HU). On post-contrast images, median peak contrast enhancement in the right ventricle (111.77 HU, 36.09-141.60 HU) was achieved in 3.1 s (range 2.9-7.3 s), in the aorta (149.30 HU, 99.43-319.60 HU) and left atrium (180.83 HU, 88.53-266.84 HU) in 6.4 s (range 5.6-7.7 s) and in the left ventricle (147.89 HU, 57.23-245.77 HU) in 7.10 s (range 6.2-11.2 s). Significantly higher attenuation was measured between all chambers and walls, the right ventricular lumen and interventricular septum (median ratio 53.78 HU, range 0.21-83.20 HU), left ventricular lumen and left ventricular free wall (89.32 HU, 38.81-185.95 HU) and aorta and periaortic fat (190.43 HU, 143.22-425.44 HU) on post-contrast images. Sufficient biological contrast is available on survey CT to discriminate between the aorta and the left atrium, and microdose MDCTA provides sufficient contrast enhancement for adequate visualization of the heart chambers in normal cats. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Orthopedic applications of single photon emission computed Tomographic bone scanning

    International Nuclear Information System (INIS)

    Collier, B.D.

    1987-01-01

    When compared with planar bone scanning, single photon emission computed tomography (SPECT) has technical advantages of potential diagnostic significance. Planar imaging often superimposes substantial underlying or overlying activity on the bony structure of medical interest. SPECT, however, can be used to remove such unwanted activity. For example, in the hip the acetabulum extends downwards behind the femoral head. Therefore when using planar bone scanning techniques, the photon-deficient defect typical of avascular necrosis (AVN) of the femoral had may be obscured by activity originating in the underlying acetabulum. By using SPECT, underlying and overlying distributions of activity can be separated into sequential tomographic planes. For this reason SPECT facilitates the detection of AVN of the femoral head. When referring a patient without a history of malignancy for bone scanning, the orthopaedic surgeon usually has a specific clinical question involving a limited portion of the skeleton. Orthopaedic surgeons at their institution commonly use bone scanning to clarify the cause of back, hip or knee pain; to determine with a physiological test the significance of radiographic findings; and to establish the extent of disease at symptomatic skeletal sites such as the three compartments of the knee. In instances such as these, when clinical concern is limited to a specific anatomical region, a bone scan procedure that includes SPECT imaging of only a portion of the skeleton is appropriate. To date, SPECT of the skeletal system has most frequently been used to evaluate patients with pain the larger joints and bony structures such as the lumbar spine, hips, knees, or temporomandibular joints (TMJ)

  8. COMPUTED TOMOGRAPHIC EVALUATION OF POSTERIOR REVERSIBLE ENCEPHALOPATHY SYNDROME

    Directory of Open Access Journals (Sweden)

    Vishwaprem Raj

    2016-04-01

    Full Text Available BACKGROUND AND PURPOSE Posterior Reversible Encephalopathy Syndrome (PRES is a neurotoxic state that occurs secondary to the inability of posterior circulation to autoregulate. The clinical spectrum and the underlying pathophysiology are still poorly defined. No conclusive evidence has been put forward regarding the relationship between clinical conditions and specific imaging findings of severity or location of oedema. PURPOSE To assess the role of computed tomography in evaluation of Posterior Reversible Encephalopathy Syndrome. MATERIALS AND METHODS 55 patients referred to the Department of Radio-Diagnosis, with a history of neurological abnormalities, including altered mental function, visual loss, stupor with a predisposing history favouring PRES and followed up for a period of 10 – 30 days. RESULTS 21 patients (38.2% were females. 32 patients (58.1% were in the age group between 21 to 30 years. Predisposing condition; 16 (29.1% presented with pre-eclampsia, 12 (21.8% with post-partum status in altered sensorium, 9 (16.4% with seizures, 7 (12.7% with hypertension, 6 (10.9% with visual disturbances, 4 (7.3% with eclampsia and 1 (1.8% with uraemia. 20 cases (36.4% showed findings suggestive of posterior reversible encephalopathy syndrome on initial computed tomography examination. 35 cases showed no initial radiological evidence suggestive of posterior reversible encephalopathy syndrome. Of the 20 cases which showed computed tomographic evidence of posterior reversible encephalopathy syndrome, recovery was noted in 5 cases (9.1%. Persistence of findings detected on first CT was noted in 13 patients (23.6%. Regional predominance of the lesions was as follows. Frontal lobe (39%, Parietal lobe (32%, Temporal lobe (15% and occipital lobe (15%. CONCLUSION Varied clinical manifestations are associated with anatomical findings recognisable by neuro-imaging as PRES. Prompt imaging is necessary for the recognition of the condition and appropriate

  9. Tomographic apparatus and method for reconstructing planar slices from non-absorbed radiation

    International Nuclear Information System (INIS)

    1976-01-01

    In a tomographic apparatus and method for reconstructing two-dimensional planar slices from linear projections of non-absorbed radiation useful in the fields of medical radiology, microscopy, and non-destructive testing, a beam of radiation in the shape of a fan is passed through an object lying in the same quasi-plane as the object slice and non-absorbtion thereof is recorded on oppositely-situated detectors aligned with the source of radiation. There is relative rotation between the source-detector configuration and the object within the quasi-plane. Periodic values of the detected radiation are taken, convolved with certain functions, and back-projected to produce a two-dimensional output picture on a visual display illustrating a facsimile of the object slice. A series of two-dimensional pictures obtained simultaneously or serially can be combined to produce a three dimensional portrayal of the entire object

  10. Enhancement of precision and reduction of measuring points in tomographic reconstructions

    International Nuclear Information System (INIS)

    Lustfeld, H.; Hirschfeld, J.A.; Reissel, M.; Steffen, B.

    2011-01-01

    Accurate external measurements are required in tomographic problems to obtain a reasonable knowledge of the internal structures. Crucial is the distribution of the external measuring points. We suggest a procedure how to systematically optimize this distribution viz. to increase the precision (i.e. to shrink error bars) of the reconstruction by detecting the important and by eliminating the irrelevant measuring points. In a realistic numerical example we apply our scheme to magnetotomography of fuel cells. The result is striking: Starting from a smooth distribution of measuring points on a surface of a cuboid around the fuel cell, the number of measuring points can systematically be reduced by more than 90%. At the same time the precision increases by a factor of nearly 3.

  11. Applicability of a set of tomographic reconstruction algorithms for quantitative SPECT on irradiated nuclear fuel assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsson Svärd, Staffan, E-mail: staffan.jacobsson_svard@physics.uu.se; Holcombe, Scott; Grape, Sophie

    2015-05-21

    A fuel assembly operated in a nuclear power plant typically contains 100–300 fuel rods, depending on fuel type, which become strongly radioactive during irradiation in the reactor core. For operational and security reasons, it is of interest to experimentally deduce rod-wise information from the fuel, preferably by means of non-destructive measurements. The tomographic SPECT technique offers such possibilities through its two-step application; (1) recording the gamma-ray flux distribution around the fuel assembly, and (2) reconstructing the assembly's internal source distribution, based on the recorded radiation field. In this paper, algorithms for performing the latter step and extracting quantitative relative rod-by-rod data are accounted for. As compared to application of SPECT in nuclear medicine, nuclear fuel assemblies present a much more heterogeneous distribution of internal attenuation to gamma radiation than the human body, typically with rods containing pellets of heavy uranium dioxide surrounded by cladding of a zirconium alloy placed in water or air. This inhomogeneity severely complicates the tomographic quantification of the rod-wise relative source content, and the deduction of conclusive data requires detailed modelling of the attenuation to be introduced in the reconstructions. However, as shown in this paper, simplified models may still produce valuable information about the fuel. Here, a set of reconstruction algorithms for SPECT on nuclear fuel assemblies are described and discussed in terms of their quantitative performance for two applications; verification of fuel assemblies' completeness in nuclear safeguards, and rod-wise fuel characterization. It is argued that a request not to base the former assessment on any a priori information brings constraints to which reconstruction methods that may be used in that case, whereas the use of a priori information on geometry and material content enables highly accurate quantitative

  12. Computer tomographic detection of an intraspinal arachnoidal cyst

    Energy Technology Data Exchange (ETDEWEB)

    Kuckein, D; Walter, K; Paal, G

    1981-03-01

    A 46 year old female patient who after 3-4 weeks of influenza suffered from strong headaches, vomiting and rotatory vertigo was subjected to a myelograph and then to a computerized tomographic investigation due to suspect cerebrospinal fluid. The computerized tomography is better than the myelography in diagnosing intraspinal arachnoidal cysts, however this should be preceded by most accurate possible segment location.

  13. Pipelining Computational Stages of the Tomographic Reconstructor for Multi-Object Adaptive Optics on a Multi-GPU System

    KAUST Repository

    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.

  14. SU-E-J-252: A Motion Algorithm to Extract Physical and Motion Parameters of a Mobile Target in Cone-Beam Computed Tomographic Imaging Retrospective to Image Reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Ali, I; Ahmad, S [University of Oklahoma Health Sciences, Oklahoma City, OK (United States); Alsbou, N [Department of Electrical and Computer Engineering, Ada, OH (United States)

    2014-06-01

    Purpose: A motion algorithm was developed to extract actual length, CT-numbers and motion amplitude of a mobile target imaged with cone-beam-CT (CBCT) retrospective to image-reconstruction. Methods: The motion model considered a mobile target moving with a sinusoidal motion and employed three measurable parameters: apparent length, CT number level and gradient of a mobile target obtained from CBCT images to extract information about the actual length and CT number value of the stationary target and motion amplitude. The algorithm was verified experimentally with a mobile phantom setup that has three targets with different sizes manufactured from homogenous tissue-equivalent gel material embedded into a thorax phantom. The phantom moved sinusoidal in one-direction using eight amplitudes (0–20mm) and a frequency of 15-cycles-per-minute. The model required imaging parameters such as slice thickness, imaging time. Results: This motion algorithm extracted three unknown parameters: length of the target, CT-number-level, motion amplitude for a mobile target retrospective to CBCT image reconstruction. The algorithm relates three unknown parameters to measurable apparent length, CT-number-level and gradient for well-defined mobile targets obtained from CBCT images. The motion model agreed with measured apparent lengths which were dependent on actual length of the target and motion amplitude. The cumulative CT-number for a mobile target was dependent on CT-number-level of the stationary target and motion amplitude. The gradient of the CT-distribution of mobile target is dependent on the stationary CT-number-level, actual target length along the direction of motion, and motion amplitude. Motion frequency and phase did not affect the elongation and CT-number distributions of mobile targets when imaging time included several motion cycles. Conclusion: The motion algorithm developed in this study has potential applications in diagnostic CT imaging and radiotherapy to extract

  15. Computer tomographic detection of an intraspinal arachnoidal cyst

    International Nuclear Information System (INIS)

    Kuckein, D.; Walter, K.; Paal, G.; Staedtisches Krankenhaus Harlaching, Muenchen

    1981-01-01

    A 46 year old female patient who after 3-4 weeks of influenza suffered from strong headaches, vomiting and rotatory vertigo was subjected to a myelograph and then to a computerized tomographic investigation due to suspect cerebrospinal fluid. The computerized tomography is better than the myelography in diagnosing intraspinal arachnoidal cysts, however this should be preceded by most accurate possible segment location. (MG) [de

  16. Real-Space x-ray tomographic reconstruction of randomly oriented objects with sparse data frames.

    Science.gov (United States)

    Ayyer, Kartik; Philipp, Hugh T; Tate, Mark W; Elser, Veit; Gruner, Sol M

    2014-02-10

    Schemes for X-ray imaging single protein molecules using new x-ray sources, like x-ray free electron lasers (XFELs), require processing many frames of data that are obtained by taking temporally short snapshots of identical molecules, each with a random and unknown orientation. Due to the small size of the molecules and short exposure times, average signal levels of much less than 1 photon/pixel/frame are expected, much too low to be processed using standard methods. One approach to process the data is to use statistical methods developed in the EMC algorithm (Loh & Elser, Phys. Rev. E, 2009) which processes the data set as a whole. In this paper we apply this method to a real-space tomographic reconstruction using sparse frames of data (below 10(-2) photons/pixel/frame) obtained by performing x-ray transmission measurements of a low-contrast, randomly-oriented object. This extends the work by Philipp et al. (Optics Express, 2012) to three dimensions and is one step closer to the single molecule reconstruction problem.

  17. Image reconstruction for a Positron Emission Tomograph optimized for breast cancer imaging

    International Nuclear Information System (INIS)

    Virador, Patrick R.G.

    2000-01-01

    The author performs image reconstruction for a novel Positron Emission Tomography camera that is optimized for breast cancer imaging. This work addresses for the first time, the problem of fully-3D, tomographic reconstruction using a septa-less, stationary, (i.e. no rotation or linear motion), and rectangular camera whose Field of View (FOV) encompasses the entire volume enclosed by detector modules capable of measuring Depth of Interaction (DOI) information. The camera is rectangular in shape in order to accommodate breasts of varying sizes while allowing for soft compression of the breast during the scan. This non-standard geometry of the camera exacerbates two problems: (a) radial elongation due to crystal penetration and (b) reconstructing images from irregularly sampled data. Packing considerations also give rise to regions in projection space that are not sampled which lead to missing information. The author presents new Fourier Methods based image reconstruction algorithms that incorporate DOI information and accommodate the irregular sampling of the camera in a consistent manner by defining lines of responses (LORs) between the measured interaction points instead of rebinning the events into predefined crystal face LORs which is the only other method to handle DOI information proposed thus far. The new procedures maximize the use of the increased sampling provided by the DOI while minimizing interpolation in the data. The new algorithms use fixed-width evenly spaced radial bins in order to take advantage of the speed of the Fast Fourier Transform (FFT), which necessitates the use of irregular angular sampling in order to minimize the number of unnormalizable Zero-Efficiency Bins (ZEBs). In order to address the persisting ZEBs and the issue of missing information originating from packing considerations, the algorithms (a) perform nearest neighbor smoothing in 2D in the radial bins (b) employ a semi-iterative procedure in order to estimate the unsampled data

  18. Image reconstruction for a Positron Emission Tomograph optimized for breast cancer imaging

    Energy Technology Data Exchange (ETDEWEB)

    Virador, Patrick R.G. [Univ. of California, Berkeley, CA (United States)

    2000-04-01

    The author performs image reconstruction for a novel Positron Emission Tomography camera that is optimized for breast cancer imaging. This work addresses for the first time, the problem of fully-3D, tomographic reconstruction using a septa-less, stationary, (i.e. no rotation or linear motion), and rectangular camera whose Field of View (FOV) encompasses the entire volume enclosed by detector modules capable of measuring Depth of Interaction (DOI) information. The camera is rectangular in shape in order to accommodate breasts of varying sizes while allowing for soft compression of the breast during the scan. This non-standard geometry of the camera exacerbates two problems: (a) radial elongation due to crystal penetration and (b) reconstructing images from irregularly sampled data. Packing considerations also give rise to regions in projection space that are not sampled which lead to missing information. The author presents new Fourier Methods based image reconstruction algorithms that incorporate DOI information and accommodate the irregular sampling of the camera in a consistent manner by defining lines of responses (LORs) between the measured interaction points instead of rebinning the events into predefined crystal face LORs which is the only other method to handle DOI information proposed thus far. The new procedures maximize the use of the increased sampling provided by the DOI while minimizing interpolation in the data. The new algorithms use fixed-width evenly spaced radial bins in order to take advantage of the speed of the Fast Fourier Transform (FFT), which necessitates the use of irregular angular sampling in order to minimize the number of unnormalizable Zero-Efficiency Bins (ZEBs). In order to address the persisting ZEBs and the issue of missing information originating from packing considerations, the algorithms (a) perform nearest neighbor smoothing in 2D in the radial bins (b) employ a semi-iterative procedure in order to estimate the unsampled data

  19. Computed tomographic diagnosis of calcified inferior vena cava thrombus in a child with Wilm's tumor

    Energy Technology Data Exchange (ETDEWEB)

    Kirks, D R; Ponzi, J W; Korobkin, M

    1980-01-01

    A calcified thrombus in the inferior vena cava of infants and children may be imaged by computed tomography. The precise location of the calcification within the inferior vena cava may be confirmed by computed tomographic scanning during injection of intravenous contrast material.

  20. Spiral Computed Tomographic Imaging Related to Computerized Ultrasonographic Images of Carotid Plaque Morphology and Histology

    DEFF Research Database (Denmark)

    Grønholdt, Marie-Louise M.; Wagner, Aase; Wiebe, Britt 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. Clinical usefulness of facial soft tissues thickness measurement using 3D computed tomographic images

    International Nuclear Information System (INIS)

    Jeong, Ho Gul; Kim, Kee Deog; Hu, Kyung Seok; Lee, Jae Bum; Park, Hyok; Han, Seung Ho; Choi, Seong Ho; Kim, Chong Kwan; Park, Chang Seo

    2006-01-01

    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

  2. Optoelectronic Computer Architecture Development for Image Reconstruction

    National Research Council Canada - National Science Library

    Forber, Richard

    1996-01-01

    .... Specifically, we collaborated with UCSD and ERIM on the development of an optically augmented electronic computer for high speed inverse transform calculations to enable real time image reconstruction...

  3. Under the armor: X-ray computed tomographic reconstruction of the internal skeleton of Coahomasuchus chathamensis (Archosauria: Aetosauria) from the Upper Triassic of North Carolina, USA, and a phylogenetic analysis of Aetosauria.

    Science.gov (United States)

    Hoffman, Devin K; Heckert, Andrew B; Zanno, Lindsay E

    2018-01-01

    Aetosauria is a clade of heavily armored, quadrupedal omnivorous to herbivorous archosaurs known from the Late Triassic across what was the supercontinent of Pangea. Their abundance in many deposits relative to the paucity of other Triassic herbivores indicates that they were key components of Late Triassic ecosystems. However, their evolutionary relationships remain contentious due, in large part, to their extensive dermal armor, which often obstructs observation of internal skeletal anatomy and limits access to potentially informative characters. In an attempt to address this problem we reanalyzed the holotype of a recently described species of Coahomasuchus , C. chathamensis , from the Sanford sub-basin of North Carolina using computed tomography (CT). CT scans of the holotype specimen clarify preservation of the skeleton, revealing several articulated vertebrae and ribs, an isolated vertebra, left ulna, left scapula, and the right humerus, though none of the material resulted in updated phylogenetic scorings. Reexamination of aetosaur materials from the holotype locality also indicates that several isolated osteoderms and elements of the appendicular skeleton are newly referable. Based on these results, we update the Coahomasuchus chathamensis hypodigm and conduct a revised phylogenetic analysis with improved character scorings for Coahomasuchus and several other aetosaurs. Our study recovers Coahomasuchus in a polytomy with Aetosaurus and the Typothoracinae, in contrast with a recent analysis that recovered Coahomasuchus as a wild-card taxon.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

  5. Noninvasive detection of coronary artery bypass graft patency by intravenous electron beam computed tomographic angiography.

    Science.gov (United States)

    Yamakami, Shoji; Toyama, Junji; Okamoto, Mitsuhiro; Matsushita, Toyoaki; Murakami, Yoshimasa; Ogata, Masaki; Ito, Shigenori; Fukutomi, Tatsuya; Okayama, Naotsuka; Itoh, Makoto

    2003-11-01

    This study evaluates the usefullness of intravenous electron beam computed tomographic angiography (EBA) for the detection of coronary artery bypass graft patency in 43 patients (33 men and 10 women, mean age, 65 years) who had coronary artery bypass graft surgery. EBA was performed a few days before selective bypass graft angiography (SGA). Forty axial cross-sections of angiographic images of the heart were acquired consecutively by an electrocardiographic trigger signal at 40% of the RR interval, which corresponds to the end-systolic phase. EBA data were reconstructed as a three-dimensional shaded surface display of the heart and bypass grafts. Detectability of the patency of bypass gratis was evaluated, taking selective angiographic images of the bypass grafts as a gold standard. One hundred and nine grafts (96%) out of 114 grafts were subjected to evaluation: 37 grafts were left internal mammary artery grafts (LIMA), 7 were right internal mammary artery grafts (RIMA), 6 were gastroepiploic artery grafts (GEA), 7 were free gastroepiploic artery grafts with venous drainage (free-GEA), 7 were radial artery grafts (RAG), and 45 were saphenous vein gratis (SVG). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of EBA were 98%, 100%, 100%, 91%, and 98%, respectively. EBA sampled at the end-systolic period was determined to be useful for the detection of coronary artery bypass graft patency and occlusion.

  6. Computed tomographic study of 50 patients with hypodense hepatic injuries in childhood

    International Nuclear Information System (INIS)

    Pereira, Ines Minniti Rodrigues; Alvares, Beatriz Regina; Baracat, Jamal; Martins, Daniel Lahan; Pereira, Ricardo Minniti Rodrigues

    2006-01-01

    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)

  7. Computer Based Road Accident Reconstruction Experiences

    Directory of Open Access Journals (Sweden)

    Milan Batista

    2005-03-01

    Full Text Available Since road accident analyses and reconstructions are increasinglybased on specific computer software for simulationof vehicle d1iving dynamics and collision dynamics, and forsimulation of a set of trial runs from which the model that bestdescribes a real event can be selected, the paper presents anoverview of some computer software and methods available toaccident reconstruction experts. Besides being time-saving,when properly used such computer software can provide moreauthentic and more trustworthy accident reconstruction, thereforepractical experiences while using computer software toolsfor road accident reconstruction obtained in the TransportSafety Laboratory at the Faculty for Maritime Studies andTransport of the University of Ljubljana are presented and discussed.This paper addresses also software technology for extractingmaximum information from the accident photo-documentationto support accident reconstruction based on the simulationsoftware, as well as the field work of reconstruction expertsor police on the road accident scene defined by this technology.

  8. Sparse Image Reconstruction in Computed Tomography

    DEFF Research Database (Denmark)

    Jørgensen, Jakob Sauer

    In recent years, increased focus on the potentially harmful effects of x-ray computed tomography (CT) scans, such as radiation-induced cancer, has motivated research on new low-dose imaging techniques. Sparse image reconstruction methods, as studied for instance in the field of compressed sensing...... applications. This thesis takes a systematic approach toward establishing quantitative understanding of conditions for sparse reconstruction to work well in CT. A general framework for analyzing sparse reconstruction methods in CT is introduced and two sets of computational tools are proposed: 1...... contributions to a general set of computational characterization tools. Thus, the thesis contributions help advance sparse reconstruction methods toward routine use in...

  9. Frequency-domain optical tomographic image reconstruction algorithm with the simplified spherical harmonics (SP3) light propagation model.

    Science.gov (United States)

    Kim, Hyun Keol; Montejo, Ludguier D; Jia, Jingfei; Hielscher, Andreas H

    2017-06-01

    We introduce here the finite volume formulation of the frequency-domain simplified spherical harmonics model with n -th order absorption coefficients (FD-SP N ) that approximates the frequency-domain equation of radiative transfer (FD-ERT). We then present the FD-SP N based reconstruction algorithm that recovers absorption and scattering coefficients in biological tissue. The FD-SP N model with 3 rd order absorption coefficient (i.e., FD-SP 3 ) is used as a forward model to solve the inverse problem. The FD-SP 3 is discretized with a node-centered finite volume scheme and solved with a restarted generalized minimum residual (GMRES) algorithm. The absorption and scattering coefficients are retrieved using a limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) algorithm. Finally, the forward and inverse algorithms are evaluated using numerical phantoms with optical properties and size that mimic small-volume tissue such as finger joints and small animals. The forward results show that the FD-SP 3 model approximates the FD-ERT (S 12 ) solution within relatively high accuracy; the average error in the phase (<3.7%) and the amplitude (<7.1%) of the partial current at the boundary are reported. From the inverse results we find that the absorption and scattering coefficient maps are more accurately reconstructed with the SP 3 model than those with the SP 1 model. Therefore, this work shows that the FD-SP 3 is an efficient model for optical tomographic imaging of small-volume media with non-diffuse properties both in terms of computational time and accuracy as it requires significantly lower CPU time than the FD-ERT (S 12 ) and also it is more accurate than the FD-SP 1 .

  10. The 3D tomographic image reconstruction software for prompt-gamma measurement of the boron neutron capture therapy

    International Nuclear Information System (INIS)

    Morozov, Boris; Auterinen, Iiro; Kotiluoto, Petri; Kortesniemi, Mika

    2006-01-01

    A tomographic imaging system based on the spatial distribution measurement of the neutron capture reaction during Boron Neutron Capture Therapy (BNCT) would be very useful for clinical purpose. Using gamma-detectors in a 2D-panel, boron neutron capture and hydrogen neutron capture gamma-rays emitted by the neutron irradiated region can be detected, and an image of the neutron capture events can be reconstructed. A 3D reconstruction software package has been written to support the development of a 3D prompt-gamma tomographic system. The package consists of three independent modules: phantom generation, reconstruction and evaluation modules. The reconstruction modules are based on algebraic approach of the iterative reconstruction algorithm (ART), and on the maximum likelihood estimation method (ML-EM). In addition to that, two subsets of the ART, the simultaneous iterative reconstruction technique (SIRT) and the component averaging algorithms (CAV) have been included to the package employing parallel codes for multiprocessor architecture. All implemented algorithms use two different field functions for the reconstruction of the region. One is traditional voxel function, another is, so called, blob function, smooth spherically symmetric generalized Kaiser-Bessel function. The generation module provides the phantom and projections with background by tracing the prompt gamma-rays for a given scanner geometry. The evaluation module makes statistical comparisons between the generated and reconstructed images, and provides figure-of-merit (FOM) values for the applied reconstruction algorithms. The package has been written in C language and tested under Linux and Windows platforms. The simple graphical user interface (GUI) is used for command execution and visualization purposed. (author)

  11. Results of work of neurological clinic in first year of computer tomograph application

    Energy Technology Data Exchange (ETDEWEB)

    Volejnik, V; Nettl, S; Heger, L [Karlova Univ., Hradec Kralove (Czechoslovakia). Lekarska Fakulta

    1980-11-01

    The results are analyzed of one year's use of a computer tomograph (CT) by a department of neurology. Detailed comparisons with corresponding PEG and CT findings showed the accuracy of CT examinations in the descriptions of the width of the subarachnoid spaces and of the ventricular system. The advantages of CT are assessed from the medical, economic, and ethical points of view.

  12. Cost-effectiveness of computed tomographic colonography screening for colorectal cancer in the medicare population

    NARCIS (Netherlands)

    A.B. Knudsen (Amy); I. Lansdorp-Vogelaar (Iris); C.M. Rutter (Carolyn); J.E. Savarino (James); M. van Ballegooijen (Marjolein); K.M. Kuntz (Karen); A. Zauber (Ann)

    2010-01-01

    textabstractBackground The Centers for Medicare and Medicaid Services (CMS) considered whether to reimburse computed tomographic colonography (CTC) for colorectal cancer screening of Medicare enrollees. To help inform its decision, we evaluated the reimbursement rate at which CTC screening could be

  13. Correlation of computed tomographic and magnetic resonance imaging findings in cerebral infartion

    International Nuclear Information System (INIS)

    Komatsubara, Chizuko; Chuda, Moriyoshi; Taka, Toshihiko

    1989-01-01

    We evaluated neurological findings in 75 patients of cerebral infarction, and correlated computed tomographic (CT) and magnetic resonance imaging (MRI) findings. MRI was found to have the advantage when the lesion were multiple, or in the posterior fossa. MRI demonstrates the anatomical details, and lacks the bony artifact, so it is an excellent method for identification of cerebral infarction. (author)

  14. Results of work of neurological clinic in first year of computer tomograph application

    International Nuclear Information System (INIS)

    Volejnik, V.; Nettl, S.; Heger, L.

    1980-01-01

    The results are analyzed of one year's use of a computer tomograph (CT) by a department of neurology. Detailed comparisons with corresponding PEG and CT findings showed the accuracy of CT examinations in the descriptions of the width of the subarachnoid spaces and of the ventricular system. The advantages of CT are assessed from the medical, economic, and ethical points of view. (author)

  15. X-ray differential phase-contrast tomographic reconstruction with a phase line integral retrieval filter

    International Nuclear Information System (INIS)

    Fu, Jian; Hu, Xinhua; Li, Chen

    2015-01-01

    We report an alternative reconstruction technique for x-ray differential phase-contrast computed tomography (DPC-CT). This approach is based on a new phase line integral projection retrieval filter, which is rooted in the derivative property of the Fourier transform and counteracts the differential nature of the DPC-CT projections. It first retrieves the phase line integral from the DPC-CT projections. Then the standard filtered back-projection (FBP) algorithms popular in x-ray absorption-contrast CT are directly applied to the retrieved phase line integrals to reconstruct the DPC-CT images. Compared with the conventional DPC-CT reconstruction algorithms, the proposed method removes the Hilbert imaginary filter and allows for the direct use of absorption-contrast FBP algorithms. Consequently, FBP-oriented image processing techniques and reconstruction acceleration softwares that have already been successfully used in absorption-contrast CT can be directly adopted to improve the DPC-CT image quality and speed up the reconstruction

  16. Computed-tomographic and conventional linear-tomographic evaluation of tracheobronchial lesions for laser photoresection

    International Nuclear Information System (INIS)

    Pearlberg, J.L.; Sandler, M.A.; Kvale, P.; Beute, G.H.; Madrazo, B.L.

    1985-01-01

    Laser therapy is a new modality for treatment of airway lesions. The authors examined 18 patients prior to laser photoresection of tracheobronchial lesions. Thirteen had cancers involving the distal trachea, carina, and/or proximal bronchi; five had benign lesions of the middle or proximal trachea. Each patient was examined by conventional linear tomography (CLT) and computed tomography (CT). CT was valuable in patients who had lesions of the distal trachea, carina, and/or proximal bronchi. Its particular usefulness, and its advantage relative to CLT, consisted in its ability to delineate vascular structures adjacent to the planned area of photoresection. Neither CLT nor CT was helpful in evaluation of benign lesions of the proximal trachea

  17. Continuous analog of multiplicative algebraic reconstruction technique for computed tomography

    Science.gov (United States)

    Tateishi, Kiyoko; Yamaguchi, Yusaku; Abou Al-Ola, Omar M.; Kojima, Takeshi; Yoshinaga, Tetsuya

    2016-03-01

    We propose a hybrid dynamical system as a continuous analog to the block-iterative multiplicative algebraic reconstruction technique (BI-MART), which is a well-known iterative image reconstruction algorithm for computed tomography. The hybrid system is described by a switched nonlinear system with a piecewise smooth vector field or differential equation and, for consistent inverse problems, the convergence of non-negatively constrained solutions to a globally stable equilibrium is guaranteed by the Lyapunov theorem. Namely, we can prove theoretically that a weighted Kullback-Leibler divergence measure can be a common Lyapunov function for the switched system. We show that discretizing the differential equation by using the first-order approximation (Euler's method) based on the geometric multiplicative calculus leads to the same iterative formula of the BI-MART with the scaling parameter as a time-step of numerical discretization. The present paper is the first to reveal that a kind of iterative image reconstruction algorithm is constructed by the discretization of a continuous-time dynamical system for solving tomographic inverse problems. Iterative algorithms with not only the Euler method but also the Runge-Kutta methods of lower-orders applied for discretizing the continuous-time system can be used for image reconstruction. A numerical example showing the characteristics of the discretized iterative methods is presented.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    Wong, S.T.C.

    1997-01-01

    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 screenclose quotes. To confine the scope, this presentation will not discuss such approaches

  20. Tomographic Reconstruction of Tracer Gas Concentration Profiles in a Room with the Use of a Single OP-FTIR and Two Iterative Algorithms: ART and PWLS.

    Science.gov (United States)

    Park, Doo Y; Fessier, Jeffrey A; Yost, Michael G; Levine, Steven P

    2000-03-01

    Computed tomographic (CT) reconstructions of air contaminant concentration fields were conducted in a room-sized chamber employing a single open-path Fourier transform infrared (OP-FTIR) instrument and a combination of 52 flat mirrors and 4 retroreflectors. A total of 56 beam path data were repeatedly collected for around 1 hr while maintaining a stable concentration gradient. The plane of the room was divided into 195 pixels (13 × 15) for reconstruction. The algebraic reconstruction technique (ART) failed to reconstruct the original concentration gradient patterns for most cases. These poor results were caused by the "highly underdetermined condition" in which the number of unknown values (156 pixels) exceeds that of known data (56 path integral concentrations) in the experimental setting. A new CT algorithm, called the penalized weighted least-squares (PWLS), was applied to remedy this condition. The peak locations were correctly positioned in the PWLS-CT reconstructions. A notable feature of the PWLS-CT reconstructions was a significant reduction of highly irregular noise peaks found in the ART-CT reconstructions. However, the peak heights were slightly reduced in the PWLS-CT reconstructions due to the nature of the PWLS algorithm. PWLS could converge on the original concentration gradient even when a fairly high error was embedded into some experimentally measured path integral concentrations. It was also found in the simulation tests that the PWLS algorithm was very robust with respect to random errors in the path integral concentrations. This beam geometry and the use of a single OP-FTIR scanning system, in combination with the PWLS algorithm, is a system applicable to both environmental and industrial settings.

  1. Midline oligodendrogliomas as studied by means of computed tomographic, angiographic, and positron-emission tomographic evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Kenji; Kowada, Masayoshi; Sakamoto, Tetsuya; Mineura, Katsuyoshi (Akita Univ. (Japan). Hospital)

    1989-08-01

    Five patients with intraventricular oligodendroglioma involving the lateral ventricle were reviewed by computed tomography (CT), cerebral angiography, and positron-emission tomography (PET) to delineate specific neuroradiological features of the tumors in comparison to those involving the cerebral hemispheres. Intraventricular mass lesions, extending largely from the anterior horn to the body or trigone of the lateral ventricle, were seen as hyperdense tumors in on CT; none was iso- or hypodense. Asymmetrical dilation of the lateral ventricles was noted. Noteworthy was the fact that all of the lesions demonstrated a homogeneous contrast enhancement. Calcification or hypodense areas within the tumor matrix suggestive of cyst formation were found in 4 cases. No peritumoral edema was demonstrated. On angiograms, in all cases the tumors were visualized as hypervascular, space occupying mass lesions supplied by such feeding arteries as anterior and posterior choroidal, lenticulo-striate, thalamo-perforating, and pericallosal arteries. Among these arteries, either medial or lateral posterior choroidal arteries, or both, were commonly seen in these vascular tumors. Fine tumor vessels were also seen in the distal portion of these arteries. They were accompanied by a homogeneous tumor stain at either the late-arterial, capillary, or early-venous phase. PET images from a 21 year old female showed that the intraventricular tumor had an increased cerebral blood flow and volume at the tumor site, indicating a hypervascular tumor. However, this tumor was considered less malignant on the basis of its decreased rate of glycolysis, as evaluated by PET studies with 18-F-deoxyglucose. Lateral ventricular oligodendrogliomas, synonymously termed 'midline oligodendrogliomas,' have fairly specific neuroradiological features different from those of hemispheric oligodendrogliomas.

  2. Cerebellar hemangioblastomas with computed tomographic, angiographic, and positron-emission tomographic evaluations

    International Nuclear Information System (INIS)

    Kikuchi, Kenji; Sakamoto, Tetsuya; Kowada, Masayoshi; Tamakawa, Yoshiharu; Uemura, Kazuo.

    1986-01-01

    Ten patients with cerebellar hemangioblastomas were reviewed, and evaluations were made by computed tomography (CT), vertebral angiography, and positron-emission tomography (PET). Cerebellar hemangioblastomas were classified into three types on the basis of their CT appearances: Type I: a cystic tumor without a demonstrable mural nodule; Type II: a cystic tumor with a mural nodule, and Type III: a solid tumor without any cyst formation. All of the cystic tumors classified here as Types I and II were associated with a shift and deformity of the fourth ventricule and an enlarged lateral ventricle, and yet no low-density area in the adjacent cerebellar tissue indicating perifocal edema was demonstrated. By contrast, in the solid hemangioblastomas designated as Type III, finger-shaped, low-density areas were visualized around the enhancing mass lesion, extending to the white matter of the entire affected cerebellar hemisphere. The vertebral angiographic classification of cerebellar hemangioblastomas was also attempted as follows: Type I: an avascular tumor without a demonstrable mural nodule; Type II: an avascular tumor with a mural nodule, and Type III: a solid vascular tumor with enlarged feeding arteries and distinct draining veins. In Type II, a relatively small mural nodule was visualized, fed mostly by a single feeding artery, and the tumor stain was at its peak at the arterial phase. No draining vein was opacified in most cases. In contrast, solid tumors classified as Type III were demonstrated to be hypervascular tumors with a multiplicity of feeding arteries and draining veins. The vascular mass remained to be opacified through the venous phase with delayed blood circulation. PET was performed on a 31-year-old male with a solid hemangioblastoma. (J.P.N)

  3. Analysis of stability of tomographic reconstruction of x-ray medical images

    Directory of Open Access Journals (Sweden)

    Л. А. Булавін

    2017-09-01

    Full Text Available Slice reconstruction in X-ray computed tomography is reduced to the solution of integral equations, or a system of algebraic equations in discrete case. It is considered to be an ill-posed problem due to the inconsistencies in the number of equations and variables and due to errors in the experimental data. Therefore, determination of the best method of the slice reconstruction is of great interest. Furthermore, all available methods give approximate results. The aim of this article was two-fold: i to compare two methods of image reconstruction, viz. inverse projection and variation, using the numerical experiment; ii to obtain the relationship between image accuracy and experimental error. It appeared that the image obtained by inverse projection is unstable: there was no convergence of the approximate image to the accurate one, when the experimental error reached zero. In turn, the image obtained by variational method was accurate at zero experimental error. Finally, the latter showed better slice reconstruction, despite the low number of projections and the experimental errors.

  4. Computed tomographic evaluation of the altered pancreas in dog and cat

    International Nuclear Information System (INIS)

    Posch, B.

    2002-11-01

    Eighteen dogs and 12 cats of varying breed, age and sex underwent a computed tomographic study of the pancreas. Length, diameter and density of each lobe of the pancreas were measured. Further, the gained results were compared to the information established by the clinical examination, sonography, haematology and histology. Contrast CT improved evaluation of the pancreas in all cases of normal life controls. CT criteria such as changes in size, density, delimitation of the pancreas and the peripancreatic structures were analyzed. Increased pancreatic size was seen in inflammatory as well as in neoplastic diseases. There were no reliable computed tomographic criteria to differentiate pancreatic neoplasia from inflammation without peripancreatic findings. Ultrasonography proved to be a good screening method in this study: sonographic and computed tomographic results correlated in all cases with the exception of 5 cases. In contrast to ultrasonography CT could differentiate normal pancreas from pancreas atrophy. Computed tomography was superior to sonography in determining the full extent of pancreatic and peripancreatic signs due to the good overview and overall image of the abdominal structures. Serum chemistry of a- amylase and lipase were obtained in 28 animals. Assays of serum lipase and a- amylase activities were only able to detect acute pancreatitis in half of the canine cases. Despite morphological alterations detected with the help of sonography or CT, there were no significant increases in a- amylase and lipase in cats. Following computed tomography the pancreas of 10 animals was examined pathohistologically. With the exception of 2 cases the computed tomographic results correlated with the pathohistological findings. In conclusion, computed tomography (CT) proved to be a valuable method to evaluate the localization, the full extent and the seriousness of pancreatic lesions. (author)

  5. Tomographic apparatus for reconstructing planar slices from non-absorbed and non-scattered radiation

    International Nuclear Information System (INIS)

    1980-01-01

    Apparatus which can be used in computerized tomographic systems for producing a fan shaped beam, detectors to be used in conjunction with the source and equipment for rotating the source supports are described. (U.K.)

  6. Micro-computed Tomographic Analysis of Mandibular Second Molars with C-shaped Root Canals.

    Science.gov (United States)

    Amoroso-Silva, Pablo Andrés; Ordinola-Zapata, Ronald; Duarte, Marco Antonio Hungaro; Gutmann, James L; del Carpio-Perochena, Aldo; Bramante, Clovis Monteiro; de Moraes, Ivaldo Gomes

    2015-06-01

    The goal of the present study was to evaluate the morphometric aspects of the internal anatomy of the root canal system of mandibular second molars with C-shaped canals. Fifty-two extracted second mandibular molars with C-shaped canals, fused roots, and radicular grooves were selected from a Brazilian population. The samples were scanned with a micro-computed tomographic scanner at a voxel size of 19.6 μm. The root canal cross sections were recorded as C1, C2, C3, and C4 root canal configurations according to the modified Melton classification. Morphometric parameters, including the major and minor diameters of the root canals, the aspect ratio, the roundness, and the tridimensional configuration (merging, symmetric, and asymmetric), were evaluated. The 3-dimensional reconstruction images of the teeth indicated an even distribution within the sample. The analysis of the prevalence of the different cross-sectional configurations of the C-shaped molars revealed that these were predominantly of the C4 and C3 configurations (1 mm from the apex) and the C1 and C2 configurations in the cervical third. According to the morphometric parameters, the C1 and the distal aspect of the C2 configurations exhibited the lowest roundness values and higher values for the area, major diameter, and aspect ratio in the apical third. Mandibular molars with C-shaped root canals exhibited similar distributions of symmetric, asymmetric, and merging type canals. The C1 configuration and the distal aspect of the C2 configuration exhibited the highest area values, low roundness values, and large apical diameters. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  7. Computer tomographic demonstration of the popliteal artery entrapment syndrome

    International Nuclear Information System (INIS)

    Alder, W.; Zwicker, H.

    1979-01-01

    The popliteal artery entrapment syndrome can be diagnosed by computer tomography with a greater degree of certainty than by angiography. The advantage of computer tomography depends on the simultaneous demonstration of the position of the vessel and of the surrounding muscles and their abnormal situation. (orig.) [de

  8. Optimization of Bayesian Emission tomographic reconstruction for region of interest quantitation

    International Nuclear Information System (INIS)

    Qi, Jinyi

    2003-01-01

    Region of interest (ROI) quantitation is an important task in emission tomography (e.g., positron emission tomography and single photon emission computed tomography). It is essential for exploring clinical factors such as tumor activity, growth rate, and the efficacy of therapeutic interventions. Bayesian methods based on the maximum a posteriori principle (or called penalized maximum likelihood methods) have been developed for emission image reconstructions to deal with the low signal to noise ratio of the emission data. Similar to the filter cut-off frequency in the filtered backprojection method, the smoothing parameter of the image prior in Bayesian reconstruction controls the resolution and noise trade-off and hence affects ROI quantitation. In this paper we present an approach for choosing the optimum smoothing parameter in Bayesian reconstruction for ROI quantitation. Bayesian reconstructions are difficult to analyze because the resolution and noise properties are nonlinear and object-dependent. Building on the recent progress on deriving the approximate expressions for the local impulse response function and the covariance matrix, we derived simplied theoretical expressions for the bias, the variance, and the ensemble mean squared error (EMSE) of the ROI quantitation. One problem in evaluating ROI quantitation is that the truth is often required for calculating the bias. This is overcome by using ensemble distribution of the activity inside the ROI and computing the average EMSE. The resulting expressions allow fast evaluation of the image quality for different smoothing parameters. The optimum smoothing parameter of the image prior can then be selected to minimize the EMSE

  9. Use of computed tomography and computed tomographic myelography for assessment of spinal tumoral calcinosis in a dog

    International Nuclear Information System (INIS)

    Ham, L.M. van; Bree, H.J. van; Tshamala, M.; Thoonen, H.

    1995-01-01

    Spinal tumoral calcinosis is reported in a Berner sennenhund puppy. The condition was manifested clinically as a non-ambulatory tetraparesis associated with neck pain. On survey radiographs there was a focal calcified mass at the atlantoaxial articulation. Computed tomography and computed tomographic myelography gave additional information on the extent of the mass and on the degree of spinal cord compression. The mass was removed surgically and the dog made a complete recovery

  10. Phillips-Tikhonov regularization with a priori information for neutron emission tomographic reconstruction on Joint European Torus

    Energy Technology Data Exchange (ETDEWEB)

    Bielecki, J.; Scholz, M.; Drozdowicz, K. [Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow (Poland); Giacomelli, L. [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Istituto di Fisica del Plasma “P. Caldirola,” Milano (Italy); Kiptily, V.; Kempenaars, M. [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Conroy, S. [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Department of Physics and Astronomy, Uppsala University (Sweden); Craciunescu, T. [IAP, National Institute for Laser Plasma and Radiation Physics, Bucharest (Romania); Collaboration: EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2015-09-15

    A method of tomographic reconstruction of the neutron emissivity in the poloidal cross section of the Joint European Torus (JET, Culham, UK) tokamak was developed. Due to very limited data set (two projection angles, 19 lines of sight only) provided by the neutron emission profile monitor (KN3 neutron camera), the reconstruction is an ill-posed inverse problem. The aim of this work consists in making a contribution to the development of reliable plasma tomography reconstruction methods that could be routinely used at JET tokamak. The proposed method is based on Phillips-Tikhonov regularization and incorporates a priori knowledge of the shape of normalized neutron emissivity profile. For the purpose of the optimal selection of the regularization parameters, the shape of normalized neutron emissivity profile is approximated by the shape of normalized electron density profile measured by LIDAR or high resolution Thomson scattering JET diagnostics. In contrast with some previously developed methods of ill-posed plasma tomography reconstruction problem, the developed algorithms do not include any post-processing of the obtained solution and the physical constrains on the solution are imposed during the regularization process. The accuracy of the method is at first evaluated by several tests with synthetic data based on various plasma neutron emissivity models (phantoms). Then, the method is applied to the neutron emissivity reconstruction for JET D plasma discharge #85100. It is demonstrated that this method shows good performance and reliability and it can be routinely used for plasma neutron emissivity reconstruction on JET.

  11. Computed tomographic findings of progressive supranuclear palsy compared with Parkinson's disease

    Energy Technology Data Exchange (ETDEWEB)

    Yuki, Nobuhiro; Sato, Shuzo; Yuasa, Tatsuhiko; Ito, Jusuke; Miyatake, Tadashi [Niigata Univ. (Japan). School of Dentistry

    1990-10-01

    We investigated computed tomographic (CT) films of 4 pathologically documented cases of progressive supranuclear palsy (PSP) in which the clinical presentations were atypical and compared the findings with those of 15 patients with Parkinson's disease (PD). Dilatation of the third ventricle, atrophy of the midbrain tegmentum, and enlargement of the interpeduncular cistern toward the aqueduct were found to be the characteristic findings in PSP. Thus, radiological findings can be useful when the differential diagnosis between PSP and PD is clinically difficult. (author).

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jones, O.C.

    1993-05-01

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

  14. The Use of Chest Computed Tomographic Angiography in Blunt Trauma Pediatric Population.

    Science.gov (United States)

    Hasadia, Rabea; DuBose, Joseph; Peleg, Kobi; Stephenson, Jacob; Givon, Adi; Kessel, Boris

    2018-02-05

    Blunt chest trauma in children is common. Although rare, associated major thoracic vascular injuries (TVIs) are lethal potential sequelae of these mechanisms. The preferred study for definitive diagnosis of TVI in stable patients is computed tomographic angiography imaging of the chest. This imaging modality is, however, associated with high doses of ionizing radiation that represent significant carcinogenic risk for pediatric patients. The aim of the present investigation was to define the incidence of TVI among blunt pediatric trauma patients in an effort to better elucidate the usefulness of computed tomographic angiography use in this population. A retrospective cohort study was conducted including all blunt pediatric (age blunt trauma victims, 119,821patients were younger than 14 years. Twelve (0.0001%, 12/119821) of these children were diagnosed with TVI. The most common mechanism in this group was pedestrian hit by a car. Mortality was 41.7% (5/12). Thoracic vascular injury is exceptionally rare among pediatric blunt trauma victims but does contribute to the high morbidity and mortality seen with blunt chest trauma. Computed tomographic angiography, with its associated radiation exposure risk, should not be used as a standard tool after trauma in injured children. Clinical protocols are needed in this population to minimize radiation risk while allowing prompt identification of life-threatening injuries.

  15. Evaluation of paranasal sinus mucosa in coal worker's pneumoconiosis - A computed tomographic study

    Energy Technology Data Exchange (ETDEWEB)

    Ozdemir, H.; Altin, R.; Mahmutyazicioglu, K.; Kart, L.; Uzun, L.; Savranlar, A.; Davcanci, H.; Gundogdu, S. [Zonguldak Karaelmas University, Zonguldak (Turkey). School of Medicine

    2004-09-01

    Objective: To evaluate by computed tomographic scanning the paranasal mucosal changes of coal workers with and without pneumoconiosis. Methods: Examination of images and scores from paranasal computed tomographic scans. The study participants were 26 coal workers with pneumoconiosis, 29 coal workers without pneumoconiosis, and 20 controls. All were men. The extent and patterns of inflamatory paranasal sinus disease were evaluated on computed, tomographic scans by 2 radiologists using the terminology and definitions of Newman and associates. Results: Interobserver agreement for the presence of abnormalities was from good to excellent (K, 0.63-0.89). The mucosal scores of individuals and groups were higher for coal workers than for control subjects. Both scores were significantly higher in the pneumoconiosis group than in the 2 other groups. Conclusions: This study shows that paranasal sinuses were affected more severely in coal workers than in control subjects. In coal workers with pneumoconiosis, the affection was most severe. The relationship between coal dust exposure and paranasal mucosal changes needs further study.

  16. A novel technique to incorporate structural prior information into multi-modal tomographic reconstruction

    International Nuclear Information System (INIS)

    Kazantsev, Daniil; Dobson, Katherine J; Withers, Philip J; Lee, Peter D; Ourselin, Sébastien; Arridge, Simon R; Hutton, Brian F; Kaestner, Anders P; Lionheart, William R B

    2014-01-01

    There has been a rapid expansion of multi-modal imaging techniques in tomography. In biomedical imaging, patients are now regularly imaged using both single photon emission computed tomography (SPECT) and x-ray computed tomography (CT), or using both positron emission tomography and magnetic resonance imaging (MRI). In non-destructive testing of materials both neutron CT (NCT) and x-ray CT are widely applied to investigate the inner structure of material or track the dynamics of physical processes. The potential benefits from combining modalities has led to increased interest in iterative reconstruction algorithms that can utilize the data from more than one imaging mode simultaneously. We present a new regularization term in iterative reconstruction that enables information from one imaging modality to be used as a structural prior to improve resolution of the second modality. The regularization term is based on a modified anisotropic tensor diffusion filter, that has shape-adapted smoothing properties. By considering the underlying orientations of normal and tangential vector fields for two co-registered images, the diffusion flux is rotated and scaled adaptively to image features. The images can have different greyscale values and different spatial resolutions. The proposed approach is particularly good at isolating oriented features in images which are important for medical and materials science applications. By enhancing the edges it enables both easy identification and volume fraction measurements aiding segmentation algorithms used for quantification. The approach is tested on a standard denoising and deblurring image recovery problem, and then applied to 2D and 3D reconstruction problems; thereby highlighting the capabilities of the algorithm. Using synthetic data from SPECT co-registered with MRI, and real NCT data co-registered with x-ray CT, we show how the method can be used across a range of imaging modalities. (paper)

  17. Computed tomographic brain scanning in the diagnosis of metastatic neoplasms

    International Nuclear Information System (INIS)

    Ringelstein, E.B.; Zeumer, H.; Hacke, W.; Keulers, P.

    1981-01-01

    Clinical investigations and computed brain scanning were done in 305 patients with primary extracerebral malignant tumours. One third of the patients had cerebral metastases. In most patients with brain metastases extracerebral secondary tumours were known already. Silent brain metastases were present in only 0.6% of all investigated tumour patients. All other patients had either objective neurologic-psychiatric defects or at least symptoms (headache, vomiting). Use of cranial computed tomography in all tumour patients as a pure screening method is thus not justified. The indication for the investigation is dependent on the clinical symptomatology. However, not only objective neurologic-psychiatric defects must be taken into account, but also occurrence of new symptoms. (orig.) [de

  18. Computed tomographic practice and dosimetry: implications for nuclear medicine: editorial

    International Nuclear Information System (INIS)

    Mountford, P.J.; Harding, L.K.

    1992-01-01

    This editorial briefly discusses the results of an NRPB survey of x-ray computed tomography practice and dosimetry in the UK. A wide variation in practice and patient doses was revealed. The implications for nuclear medicine are considered. The NRPB is to issue formal guidance on protection of the patient undergoing a CT investigation with the aim of achieving a more systematic approach to the justification and optimization of such exposures. (UK)

  19. Computer tomographic diagnosis of lung abscesses and pleural empyemas

    Energy Technology Data Exchange (ETDEWEB)

    Luetgemeier, J.; Wunschik, F.

    1983-06-01

    Lung abscesses are characterised by irregular air spaces with non-homogeneous necrosis. Pleural empyemas often assume a sickle shape up against the thoracic wall and tend to be homogeneous. Problems in differential diagnosis may occur if the process is not confined to an exact anatomic position. A peripheral perforating abscess is isolated from the tracheobronchial system by thickened pleura and by its capsule; even if computer tomography does not show clear-cut findings, operative intervention is indicated.

  20. Computer tomographic assessment of postoperative peripancreatic collections after distal pancreatectomy.

    Science.gov (United States)

    Uchida, Yuichiro; Masui, Toshihiko; Sato, Asahi; Nagai, Kazuyuki; Anazawa, Takayuki; Takaori, Kyoichi; Uemoto, Shinji

    2018-03-27

    Peripancreatic collections occur frequently after distal pancreatectomy. However, the sequelae of peripancreatic collections vary from case to case, and their clinical impact is uncertain. In this study, the correlations between CT findings of peripancreatic collections and complications after distal pancreatectomy were investigated. Ninety-six consecutive patients who had undergone distal pancreatectomy between 2010 and 2015 were retrospectively investigated. The extent and heterogeneity of peripancreatic collections and background clinicopathological characteristics were analyzed. The extent of peripancreatic collections was calculated based on three-dimensional computed tomography images, and the degree of heterogeneity of peripancreatic collections was assessed based on the standard deviation of their density on computed tomography. Of 85 patients who underwent postoperative computed tomography imaging, a peripancreatic collection was detected in 77 (91%). Patients with either a large extent or a high degree of heterogeneity of peripancreatic collection had a significantly higher rate of clinically relevant pancreatic fistula than those without (odds ratio 5.95, 95% confidence interval 2.12-19.72, p = 0.001; odds ratio 8.0, 95% confidence interval 2.87-24.19, p = 0.0001, respectively). A large and heterogeneous peripancreatic collection was significantly associated with postoperative complications, especially clinically relevant postoperative pancreatic fistula. A small and homogenous peripancreatic collection could be safely observed.

  1. Numerical evaluation of methods for computing tomographic projections

    International Nuclear Information System (INIS)

    Zhuang, W.; Gopal, S.S.; Hebert, T.J.

    1994-01-01

    Methods for computing forward/back projections of 2-D images can be viewed as numerical integration techniques. The accuracy of any ray-driven projection method can be improved by increasing the number of ray-paths that are traced per projection bin. The accuracy of pixel-driven projection methods can be increased by dividing each pixel into a number of smaller sub-pixels and projecting each sub-pixel. The authors compared four competing methods of computing forward/back projections: bilinear interpolation, ray-tracing, pixel-driven projection based upon sub-pixels, and pixel-driven projection based upon circular, rather than square, pixels. This latter method is equivalent to a fast, bi-nonlinear interpolation. These methods and the choice of the number of ray-paths per projection bin or the number of sub-pixels per pixel present a trade-off between computational speed and accuracy. To solve the problem of assessing backprojection accuracy, the analytical inverse Fourier transform of the ramp filtered forward projection of the Shepp and Logan head phantom is derived

  2. Contrast enhancement by arterial perfusion during computed tomography (computed tomographic arteriography) of the pancreatic disease

    International Nuclear Information System (INIS)

    Takaki, Yukiari

    1983-01-01

    Computed tomographic arteriography (CTA) was performed on 52 cases of pancreatic disease in which was suspected clinically, and in which other method failed to yield a definitive diagnosis. For CTA, 65% meglumine diatrizoate 20 ml, diluted 1:3, was injected via a catherter inserted in an artery connected with the pancreas and the change with time of the pacreas CT number was studied. The normal pancreas stains deeply and the best contrast enhancement was obtained between 17 to 21 seconds after instillation of contrast medium. In the CTA findings in pancreatic cancer, low density areas with irregular internal structures are characteristic, and these characteristics were seen even in minute pancreatic cancers which could not be recognized by CT or the intravenous bolus injection method. On the other hand, in chronic pancreatitis, even when differentiation from pancreatic cancer is difficult with arterial and venous encasement in angiography, as long as the chronic pancreatitis is not very advanced ischemic changes are not seen, and this permits differentiation form normal pancreas. This also facilitates differentiation between pancreatitis and pancreatic cancer. In the intravenous bolus injection method, the chronological change of contrast enhancement in the pancreas was studied and the best contrast enhancement was obtained after 60 to 120 seconds. This method revealed no findings peculiar to pancreatic cancer. Based on the above, CTA was found to be useful for making in contributing to establishing a definitive diagnosis, detecting minute pancreatic cancer and to differentiate pancreatic cancer from chronic pancreatitis. (author)

  3. Speeding up image reconstruction in computed tomography

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    Computed tomography (CT) is a technique for imaging cross-sections of an object using X-ray measurements taken from different angles. In last decades a significant progress has happened there: today advanced algorithms allow fast image reconstruction and obtaining high-quality images even with missing or dirty data, modern detectors provide high resolution without increasing radiation dose, and high-performance multi-core computing devices are there to help us solving such tasks even faster. I will start with CT basics, then briefly present existing classes of reconstruction algorithms and their differences. After that I will proceed to employing distinctive architectural features of modern multi-core devices (CPUs and GPUs) and popular program interfaces (OpenMP, MPI, CUDA, OpenCL) for developing effective parallel realizations of image reconstruction algorithms. Decreasing full reconstruction time from long hours up to minutes or even seconds has a revolutionary impact in diagnostic medicine and industria...

  4. Branchial cleft anomalies and their mimics: computed tomographic evaluation

    International Nuclear Information System (INIS)

    Harnsberger, H.R.; Mancuso, A.A.; Muraki, A.S.; Byrd, S.E.; Dillon, W.P.; Johnson, L.P.; Hanafee, W.N.

    1984-01-01

    A review was made of the clinical records and radiographic examinations of 38 patients with neck lesions clinically suspected of being branchial cleft anomalies. The impact of computed tomography in this sometimes confusing clinical picture was assessed and CT criteria for diagnosing branchial cleft anomalies (BCAs) and differentiating them from their mimics were identified. Seventeen branchial cleft anomalies and 21 BCA mimics were evaluated. A definitive CT diagnosis of second branchial cleft cysts based on characteristic morphology, location, and displacement of surrounding structures was possible in 80% of cases. CT was found to be the best radiographic examination in making a definitive diagnosis of BCA if a neck mass was present

  5. Computed tomographic findings of early subacute sclerosing panencephalitis

    International Nuclear Information System (INIS)

    Pedersen, H.; Wulff, C.H.; Rigshospitalet, Copenhagen

    1982-01-01

    Computed tomography of the brain (CT) was carried out at the early stages of subacute sclerosing panencephalitis (SSPE) in three children. The lateral ventricles were very small and the hemispheric sulci and interhemispheric fissures were not visible in all three patients in contrast to severe atrophy found at a later stage in one patient. The early CT abnormalities were revealed at the same time as the titres of measles antibodies in blood and cerebrospinal fluid were elevated, and the characteristic periodic complexes in the electroencephalogram established the diagnosis of SSPE. The CT changes indicating brain swelling reflect the reactive changes of this slow virus infection. (orig.)

  6. Computed tomographic cholangiography in the diagnosis of choledocholithiasis

    International Nuclear Information System (INIS)

    Lopez-Negrete, L.; Sanchez, J. L.; Garcia-Lozano, J.; Tejeiro, A.; Salas, J.

    2001-01-01

    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

  7. Computed tomographic evaluation of dinosar egg shell integrity

    International Nuclear Information System (INIS)

    Jones, J.C.; Greenberg, W.; Ayers, S.

    1998-01-01

    The purpose of this study was to determine whether computed tomography (CT) could be used to identify hatching holes in partially embedded dinosaur eggs. One Faveololithus and two Dendroolithus eggs were examined using a fourth generation CT scanner. The eggs were partially embedded in a fossilized sediment matrix, with the exposed portion of the shell appearing intact. In CT images of all three eggs, the shells appeared hyperdense relative to the matrix. Hatching holes were visible as large gaps in the embedded portion of the shell, with inwardly displaced shell fragments. It was concluded that CT is an effective technique for nondestructively assessing dinosaur egg shell integrity

  8. Computed tomographic manifestations of abdominal and pelvic venous collaterals

    International Nuclear Information System (INIS)

    Pagani, J.J.; Thomas, J.L.; Bernardino, M.E.

    1982-01-01

    Obstruction of blood flow through the inferior vena cava and portal vein may produce venous collaterals. These include the paravertebral venous system and its communications with the ascending lumbar veins and azygous/hemiazygous system; gonadal, periureteric, and other retroperitoneal veins; abdominal wall veins; hemorrhoidal venous plexus; and the portal venous system. The anatomic location of these vessels is discussed. Computed tomography demonstrates them as round or tubular structures that are isodens when compared with other venous structures following contrast material administration. Techniques of examination and methods of differentiation of these vascular structures from other abnormalities, especially lymphadenopathy, are discussed

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

    Science.gov (United States)

    Lukeneder, Alexander

    2012-08-01

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

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

    Science.gov (United States)

    Lukeneder, Alexander

    2012-08-01

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

  11. Linear information retrieval method in X-ray grating-based phase contrast imaging and its interchangeability with tomographic reconstruction

    Science.gov (United States)

    Wu, Z.; Gao, K.; Wang, Z. L.; Shao, Q. G.; Hu, R. F.; Wei, C. X.; Zan, G. B.; Wali, F.; Luo, R. H.; Zhu, P. P.; Tian, Y. C.

    2017-06-01

    In X-ray grating-based phase contrast imaging, information retrieval is necessary for quantitative research, especially for phase tomography. However, numerous and repetitive processes have to be performed for tomographic reconstruction. In this paper, we report a novel information retrieval method, which enables retrieving phase and absorption information by means of a linear combination of two mutually conjugate images. Thanks to the distributive law of the multiplication as well as the commutative law and associative law of the addition, the information retrieval can be performed after tomographic reconstruction, thus simplifying the information retrieval procedure dramatically. The theoretical model of this method is established in both parallel beam geometry for Talbot interferometer and fan beam geometry for Talbot-Lau interferometer. Numerical experiments are also performed to confirm the feasibility and validity of the proposed method. In addition, we discuss its possibility in cone beam geometry and its advantages compared with other methods. Moreover, this method can also be employed in other differential phase contrast imaging methods, such as diffraction enhanced imaging, non-interferometric imaging, and edge illumination.

  12. Fast parallel algorithm for three-dimensional distance-driven model in iterative computed tomography reconstruction

    International Nuclear Information System (INIS)

    Chen Jian-Lin; Li Lei; Wang Lin-Yuan; Cai Ai-Long; Xi Xiao-Qi; Zhang Han-Ming; Li Jian-Xin; Yan Bin

    2015-01-01

    The projection matrix model is used to describe the physical relationship between reconstructed object and projection. Such a model has a strong influence on projection and backprojection, two vital operations in iterative computed tomographic reconstruction. The distance-driven model (DDM) is a state-of-the-art technology that simulates forward and back projections. This model has a low computational complexity and a relatively high spatial resolution; however, it includes only a few methods in a parallel operation with a matched model scheme. This study introduces a fast and parallelizable algorithm to improve the traditional DDM for computing the parallel projection and backprojection operations. Our proposed model has been implemented on a GPU (graphic processing unit) platform and has achieved satisfactory computational efficiency with no approximation. The runtime for the projection and backprojection operations with our model is approximately 4.5 s and 10.5 s per loop, respectively, with an image size of 256×256×256 and 360 projections with a size of 512×512. We compare several general algorithms that have been proposed for maximizing GPU efficiency by using the unmatched projection/backprojection models in a parallel computation. The imaging resolution is not sacrificed and remains accurate during computed tomographic reconstruction. (paper)

  13. A computed tomographic prolective trohoc study of chronic schizophrenics

    International Nuclear Information System (INIS)

    Glueck, E.; Radue, E.W.; Mundt, C.; Gerhardt, P.

    1980-01-01

    The maximal width of the third ventricle, the maximal distance between the outer tips of the anterior horns, and the number of enlarged cerebral sulci on the two highest CT slices were measured in 68 chronic schizophrenic patients on cranial computed tomograms in order to detect a possible enlargement of the cerebrospinal fluid (CSF) filled intracranial spaces. These results were compared with values obtained from a control group which was formed in accordance with definite exclusion criteria and matched-pair parameters (sex, age and maximal inner diameter of the skull). In a prolective trohoc study no difference was found in the size of the CSF spaces of schizophrenics and the controls. The psychopathological condition of the patients, which was classified in a semistandardized dialogue, also showed no correlation with the ventricular size or the number of enlarged cerebral sulci. (orig.)

  14. Computed tomographic assessment of vertebral bone mineral in childhood

    International Nuclear Information System (INIS)

    Fredericks, B.J.; De Campo, J.F.; McCredie, D.A.

    1990-01-01

    Quantitative computed tomography (QCT) was used to assess trabecular bone mineral concentration in the vertebrae of 132 children, 45 with suspected disorder of bone mineralisation, 54 with thalassaemia and 37 controls. The range for bone mineral concentration in controls, expressed as equivalent K 2 HPO 4 concentrations, was 90-190 mg cm -3 . Abnormally low values were seen in all untreated children with idiopathic juvenile osteoporosis, 3/9 steroid recipients, and three patients with osteogenesis imperfecta. Abnormally high values were seen in 10/14 chronic renal failure patients. Comparison of the single and dual-energy methods showed that the single energy method, which has a lower radiation dose and is less prone to error from movement artifact, is satisfactory in most paediatric applications. (orig.)

  15. Computed tomographic evaluation of realignment surgery for patellar subluxation

    International Nuclear Information System (INIS)

    Inoue, Masahiro; Shino, Konsei; Maeda, Akira; Nakata, Ken; Ono, Hiroo.

    1994-01-01

    Forty-two patients with patellar subluxation underwent realignment surgery of the knee extensor mechanism. The surgery included, lateral release, advancement and reefing of the vastus medialis and the medial capsule and tibial tubercle transfer (Elmslie-Trillat procedure). The effect of surgery was evaluated using computed tomograms of the pre- and post-operative knees at 0, 15, 30 and 45 degrees of knee flexion. The degree of patellofemoral incongruence on CT was expressed using two parameters of patellar tilt and patellar shift. Thirty-three volunteers without any patello-femoral symptoms served as controls. Postoperatively both the patellar tilt and the patellar shift improved significantly. The average patellar tilt and the patellar shift of the patient group at 45 degrees were comparable with those of controls. However, it was found by CT that the realignment surgery was less effective between 0 and 30 degrees of knee flexion. (author)

  16. Computed tomographic evaluation of realignment surgery for patellar subluxation

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Masahiro (Kansai Rosai Hospital, Amagasaki (Japan)); Shino, Konsei; Maeda, Akira; Nakata, Ken; Ono, Hiroo

    1994-01-01

    Forty-two patients with patellar subluxation underwent realignment surgery of the knee extensor mechanism. The surgery included, lateral release, advancement and reefing of the vastus medialis and the medial capsule and tibial tubercle transfer (Elmslie-Trillat procedure). The effect of surgery was evaluated using computed tomograms of the pre- and post-operative knees at 0, 15, 30 and 45 degrees of knee flexion. The degree of patellofemoral incongruence on CT was expressed using two parameters of patellar tilt and patellar shift. Thirty-three volunteers without any patello-femoral symptoms served as controls. Postoperatively both the patellar tilt and the patellar shift improved significantly. The average patellar tilt and the patellar shift of the patient group at 45 degrees were comparable with those of controls. However, it was found by CT that the realignment surgery was less effective between 0 and 30 degrees of knee flexion. (author).

  17. Intra-articualr calcaneal fractures: Computed tomographic analysis

    International Nuclear Information System (INIS)

    Rosenberg, Z.S.; Feldman, F.; Singson, R.D.

    1987-01-01

    Computed tomography (CT) analysis of 21 intra-articular calcaneal fractures categorized according to the Essex-Lopresti classification revealed the following distribution: joint depression-type 57%, comminuted type 43%, tongue-type 0%. The posterior calcaneal facet was fractured and/or depressed in 100% of the cases while the medial facet was involved in only 25% of the cases. CT proved superior to plain films by consistently demonstrating additional fracture components within each major category suggesting subclassifications which have potential prognostic value. CT allowed more expeditious handling of acutely injured patients, and improved preoperative planning, postoperative follow-up, and detailed analysis of causes for chronic residual pain. CT further identified significant soft tissue injuries such as peroneal tendon displacement which cannot be delineated on plain films. (orig.)

  18. Computed tomographic analysis of calvarial hyperostosis in captive lions.

    Science.gov (United States)

    Gross-Tsubery, Ruth; Chai, Orit; Shilo, Yael; Miara, Limor; Horowitz, Igal H; Shmueli, Ayelet; Aizenberg, Itzhak; Hoffman, Chen; Reifen, Ram; Shamir, Merav H

    2010-01-01

    Osseous malformations in the skull and cervical vertebrae of lions in captivity are believed to be caused by hypovitaminosis A. These often lead to severe neurologic abnormalities and may result in death. We describe the characterization of these abnormalities based on computed tomography (CT). CT images of two affected and three healthy lions were compared with define the normal anatomy of the skull and cervical vertebrae and provide information regarding the aforementioned osseous malformations. Because bone structure is influenced by various factors other than the aforementioned disease, all values were divided by the skull width that was not affected. The calculated ratios were compared and the most pronounced abnormalities in the affected lions were, narrowing of the foramen magnum, thickening of the tentorium osseus cerebelli and thickening of the dorsal arch of the atlas. CT is useful for detection of the calvarial abnormalities in lions and may be useful in further defining this syndrome.

  19. The image of a brain stroke in a computed tomograph

    International Nuclear Information System (INIS)

    Just, E.G.

    1982-01-01

    On the basis of 100 findings from patients who suffered brain strokes and by the use of 1500 ensured stroke images it was tested whether or not the stroke-predilection typologie outlined by Zuelch is based on a coincidental summation of individual cases. The radio-computed tomography with the possibility of evaluation of non-lethal cases proved itself as a suited method for confirmation or repudiation of this stroke theory. By means of the consistently achieved association of the frontal, respectively horizontal sectional image for the typology it could be proven and - with the exception of a few rather seldom types - also demonstrated that the basic and predilection types of brain stroke repeated themselves in their pattern. In individual cases a specification of lower types could also be undertaken. (orig./TRV) [de

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

    International Nuclear Information System (INIS)

    Agha, F.P.

    1983-01-01

    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

  1. Prediction of Clinical Outcome After Acute Ischemic Stroke: The Value of Repeated Noncontrast Computed Tomography, Computed Tomographic Angiography, and Computed Tomographic Perfusion.

    Science.gov (United States)

    Dankbaar, Jan W; Horsch, Alexander D; van den Hoven, Andor F; Kappelle, L Jaap; van der Schaaf, Irene C; van Seeters, Tom; Velthuis, Birgitta K

    2017-09-01

    Early prediction of outcome in acute ischemic stroke is important for clinical management. This study aimed to compare the relationship between early follow-up multimodality computed tomographic (CT) imaging and clinical outcome at 90 days in a large multicenter stroke study. From the DUST study (Dutch Acute Stroke Study), patients were selected with (1) anterior circulation occlusion on CT angiography (CTA) and ischemic deficit on CT perfusion (CTP) on admission, and (2) day 3 follow-up noncontrast CT, CTP, and CTA. Follow-up infarct volume on noncontrast CT, poor recanalization on CTA, and poor reperfusion on CTP (mean transit time index ≤75%) were related to unfavorable outcome after 90 days defined as modified Rankin Scale 3 to 6. Four multivariable models were constructed: (1) only baseline variables (model 1), (2) model 1 with addition of infarct volume, (3) model 1 with addition of recanalization, and (4) model 1 with addition of reperfusion. Area under the curves of the receiver operating characteristic curves of the models were compared using the DeLong test. A total of 242 patients were included. Poor recanalization was found in 21%, poor reperfusion in 37%, and unfavorable outcome in 44%. The area under the curve of the receiver operating characteristic curve without follow-up imaging was 0.81, with follow-up noncontrast CT 0.85 ( P =0.02), CTA 0.86 ( P =0.01), and CTP 0.86 ( P =0.01). All 3 follow-up imaging modalities improved outcome prediction compared with no imaging. There was no difference between the imaging models. Follow-up imaging after 3 days improves outcome prediction compared with prediction based on baseline variables alone. CTA recanalization and CTP reperfusion do not outperform noncontrast CT at this time point. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00880113. © 2017 American Heart Association, Inc.

  2. Computed tomographic studies on prostate and bladder diseases

    International Nuclear Information System (INIS)

    Ono, Shuta

    1980-01-01

    The computed tomography (CT) has been performed in 6 cases of normal prostate, 4 cases of prostatitis, 6 cases of early stage of benign prostatic hyperplasia, 21 cases of late stage of benign prostatic hyperplasia, 27 cases of prostatic carcinoma, and the pneumo-CT scan with the gas-filled bladder has been performed in 10 cases of bladder carcinomas. The CT gave an excellent visualization of form of the prostate and pelvic anatomic relationships. A significant difference of EMI unit has been observed between benign prostatic hyperplasia (EMI unit: 14.6+-4.4) and prostatic carcinoma (EMI unit: 24.7+-4.4). The volume of prostate has been estimated from the following formula as an ellipsoid, π/6 A x B x C (A) maximum transverse diameter in the CT (B) anteroposterior diameter in the CT (C) length of the prostatic urethra in the urethrogram. A highly significant correlation has been recognized between the postoperative weight of the prostatic in eighteen cases and the prostatic weight estimated from this method. A new method of the pneumo-CT with the gas-filled bladder has been presented and evaluated. Direct visualization of the extent of tumor adjacent soft tissue structure is possible. It is considered that this method also has an advantage to be able to evaluate the effect of anti-cancer drug therapy. (author)

  3. Computed tomographic findings of splenic injury and correlation with treatment

    International Nuclear Information System (INIS)

    Kim, Dong Jin; Koh, Joo Yaul; Kim, Myung Soon; Hong, In Soo; Cho, Whi Youl; Sung, Ki Joon

    1990-01-01

    According to recently reported classification, 46 patients with blunt splenic trauma were evaluate preoperatively with computed tomography(CT). Injures were graded I through IV and describe as capsular or subcapsular disruptions without parenchymal injury(3 patients); capsular and parenchymal injuries(23 patients); injuries involving hilum(3 patients); and fragmentation(17 patients). Nineteen patients were managed conservatively and 27 patients were managed surgically. Twelve patients(47%) out of those with Type I or Type II were managed surgically including five hemodynamically unstable patients and seven hemodynamically stable patients with associated injuries and unknown surgical criteria. On the other hand hemodynamically stable patients(25%) out of those with Type III or Type IV were managed surgically. The amount of hemoperitoneum was graded into small, moderate and large; small in three patients, moderate in 39 patients, and large in two patients. The amount of hemoperitoneum in patients with conservative treatment was moderate in 16 patients and large in one patient. And the amount of hemoperitoneum in patients with operative treatment was small in three patients, moderate in 23 patients and large in one patient. We concluded that CT was accurate method of determining the extent of splenic injury and evaluation of hemoperitoneum, but treatment choice should be based on the hemodynamic status of patients rather than the type of injury or the amount of hemoperitoneum by CT

  4. Computed tomographic findings of splenic injury and correlation with treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Jin; Koh, Joo Yaul; Kim, Myung Soon; Hong, In Soo; Cho, Whi Youl; Sung, Ki Joon [Yonsei University Wonju College of Medicine, Wonju (Korea, Republic of)

    1990-12-15

    According to recently reported classification, 46 patients with blunt splenic trauma were evaluate preoperatively with computed tomography(CT). Injures were graded I through IV and describe as capsular or subcapsular disruptions without parenchymal injury(3 patients); capsular and parenchymal injuries(23 patients); injuries involving hilum(3 patients); and fragmentation(17 patients). Nineteen patients were managed conservatively and 27 patients were managed surgically. Twelve patients(47%) out of those with Type I or Type II were managed surgically including five hemodynamically unstable patients and seven hemodynamically stable patients with associated injuries and unknown surgical criteria. On the other hand hemodynamically stable patients(25%) out of those with Type III or Type IV were managed surgically. The amount of hemoperitoneum was graded into small, moderate and large; small in three patients, moderate in 39 patients, and large in two patients. The amount of hemoperitoneum in patients with conservative treatment was moderate in 16 patients and large in one patient. And the amount of hemoperitoneum in patients with operative treatment was small in three patients, moderate in 23 patients and large in one patient. We concluded that CT was accurate method of determining the extent of splenic injury and evaluation of hemoperitoneum, but treatment choice should be based on the hemodynamic status of patients rather than the type of injury or the amount of hemoperitoneum by CT.

  5. Computed tomographic findings in acute superior mesenteric arterial occlusion

    International Nuclear Information System (INIS)

    Kuwabara, Yoshiyuki; Kataoka, Makoto; Kureyama, Yasuyuki; Iwata, Hiroshi; Kashima, Taketoshi; Sinoda, Noriyuki; Sato, Atsushi; Hattori, Kohji; Masaoka, Akira

    1993-01-01

    In this study computed tomography (CT) findings were examined in 6 cases of acute superior mesenteric arterial (SMA) occlusion. With simple CT, occluded site of SMA revealed a slightly high density in 2 cases, while no findings were noted in other cases. Slightly dilated multiple loops of the intestine were confirmed in 3 cases, but no particular changes in the intestinal wall were found. As other findings, ascites and air in the portal vein were found in each one case. Contrast enhanced CT was conducted in 2 out of the 6 cases, and occluded site was visualized as spots in one case but no findings were noted in the other. The contrast enhancement effect in vessels in SMA region was examined from its root to the peripheral in this order, and the 2 cases showed common findings that the contrast enhancement effect abruptly disappeared at a point in vessels in SMA region (discontinuance). The point was consistent with the occluded site on angiography. These findings indicate that simple CT alone is difficult to offer correct diagnosis of SMA occlusion, but contrast enhanced CT is able to visualize the SMA occlusion as a discontinuance picture. It is thought that contrast enhanced CT can be a useful procedure for early diagnosis of SMA occlusion. (author)

  6. Adult sail sign: radiographic and computed tomographic features.

    Science.gov (United States)

    Lee, Yu-Jin; Han, Daehee; Koh, Young Hwan; Zo, Joo Hee; Kim, Sang-Hyun; Kim, Deog Kyeom; Lee, Jeong Sang; Moon, Hyeon Jong; Kim, Jong Seung; Chun, Eun Ju; Youn, Byung Jae; Lee, Chang Hyun; Kim, Sam Soo

    2008-02-01

    The sail sign is a well-known radiographic feature of the pediatric chest. This sign can be observed in an adult population as well, but for a different reason. To investigate the sail sign appearing in adult chest radiography. Based on two anecdotal adult cases in which frontal chest radiographs showed the sail sign, we prospectively screened radiographs of 10,238 patients to determine the incidence of the sail sign found in adults in their 40s or older. The cause of the sail sign was assessed using computed tomography (CT). The sail sign was revealed in 10 (seven males, three females; median age 60.6 years) of 10,238 patients. Of these 10 patients with a sail sign on frontal radiographs, eight underwent CT. The frontal radiographs of these 10 patients showed a concave superior margin toward the lung in nine patients, a concave inferior margin in five, and a double-lined inferior margin in three. Lateral radiographs disclosed a focal opacity over the minor fissure in five of six patients, which was either fuzzy (n = 4) or sharp (n = 1) in its upper margin, and was sometimes double lined in the inferior margin (n = 3). CT revealed the anterior mediastinal fat to be the cause of the radiographic sail sign, which stretched laterally from the mediastinum to insinuate into the minor fissure. The incidence of sail sign on adult chest radiographs is about 0.1%. The sign is specific enough to eliminate the need for more sophisticated imaging.

  7. Computed tomographic anatomy of the canine lumbosacral spine

    International Nuclear Information System (INIS)

    Jones, J.C.; Cartee, R.E.; Bartels, J.E.

    1995-01-01

    The lumbosacral spine (L5–S3) was examined by high resolution computed tomography (CT) in five canine cadaver specimens and one anesthetized dog using 5mm thick transverse slices at 5mm intervals. In each dog, anatomic features observed on CT images were confirmed by comparison with corresponding 5 mm thick anatomic transverse sections and section radiographs. CT anatomic features visualized in all dogs included the vertebral bodies, pedicles, laminae, articular processes, spinous processes, transverse processes, mammillary processes, basivertebral venous canals, vertebral foramina, intervertebral foramina, sacral wings, median sacral crest, intermediate sacral crests, lateral sacral crests, articular process joints, sacroiliac joints, internal vertebral venous plexus, epidural fat, thecal sac, L5–S3 nerve roots, and spinal nerves. Spinal ganglia, yellow ligaments, and portions of the intervertebral discs were visible in some dogs. The spinal cord, intrathecal nerve roots, dorsal and ventral longitudinal ligaments, spinal arteries, and radicular vessels were not distinguishable. Accessory processes were identified on the caudal L5 pedicles in most dogs, an observation that differed from descriptions in standard anatomy texts. Previously undescribed osseous grooves, termed “lateral recesses,” were identified in the caudal L7 vertebral foramen of all dogs

  8. Computed tomographic study of the complication of head injury

    International Nuclear Information System (INIS)

    Kojima, Tadashi; Waga, Shiro

    1982-01-01

    Computed tomography (CT) is quite effective in the diagnosis of traumatic intracranial hemorrhage and cerebral contusion. Two hundred and nine consecutive patients with head injury were admitted to the hospital and studied by CT in the year from 1977 to 1980. Fourty-sevenof 209 patients had the complications of head injury, including 6 patients with carotidcavernous fistula (CCF), 6 with traumatic aneurysm, 10 with pneumocephalus, 4 with intracranial foreign body, 15 with optic nerve injury, and 14 with other cranial nerve palsy. Five patients with CCF had abnormal finding on CT. Two traumatic aneurysms of the superficial temporal artery were visualized on CT after injection of contrast material, but all traumatic aneurysms of the carotid siphon were not seven on CT. CT in all 10 patients with pneumocephalus and in all 4 patients with intracranial foreign body was of diagnostic value: On CT in two patients even small air bubbles were seen in details. In the CT examination of 29 patients who presented with cranial nerve injury, we could not find out any abnormality on CT. We emphasize that CT is much less effective in the diagnosis of vascular complication of head injury and traumatic cranial nerve injury. (author)

  9. Multislice computed tomographic coronary angiography: experience in a UK centre

    International Nuclear Information System (INIS)

    Morgan-Hughes, G.J.; Marshall, A.J.; Roobottom, C.A.

    2003-01-01

    AIM: To evaluate the technique of coronary angiography with retrospectively electrocardiogram (ECG)-gated four-slice helical computed tomography (CT). MATERIALS AND METHODS: Within 1 month of undergoing routine day-case diagnostic coronary angiography, 30 consecutive patients also underwent retrospectively ECG-gated multislice CT coronary angiography. This enabled direct comparison of seven segments of proximal and mid-coronary artery for each patient by two blinded assessors. Each segment of coronary artery from the multislice CT image was evaluated initially for 'assessability' and those segments deemed assessable were subsequently investigated for the presence or absence of a significantly (n=70%) stenotic lesion. RESULTS: Overall 68% of proximal and mid-coronary artery segments were assessable. The sensitivity and specificity of four-slice CT coronary angiography in assessable segments for detecting the presence or absence (n=70%) of stenoses were 72 and 86%, respectively. These results correspond to a positive predictive value of 53% and a 93% negative predictive value. If the 32% of non-assessable segments are added into the calculation then the sensitivity and specificity fall to 49 and 66%, respectively. CONCLUSION: Although multislice CT coronary angiography is a promising technique, the overall assessability and diagnostic accuracy of four-slice CT acquisition is not sufficient to justify routine clinical use. Further, evaluation should investigate the benefit of the reduction in temporal and spatial resolution offered by 16 and 32 slice acquisition

  10. Evaluation of interpolation methods for surface-based motion compensated tomographic reconstruction for cardiac angiographic C-arm data

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Kerstin; Schwemmer, Chris; Hornegger, Joachim [Pattern Recognition Lab, Department of Computer Science, Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen 91058 (Germany); Zheng Yefeng; Wang Yang [Imaging and Computer Vision, Siemens Corporate Research, Princeton, New Jersey 08540 (United States); Lauritsch, Guenter; Rohkohl, Christopher; Maier, Andreas K. [Siemens AG, Healthcare Sector, Forchheim 91301 (Germany); Schultz, Carl [Thoraxcenter, Erasmus MC, Rotterdam 3000 (Netherlands); Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States)

    2013-03-15

    all experiments showed that TPS interpolation provided the best results. The quantitative results in the phantom experiments showed comparable nRMSE of Almost-Equal-To 0.047 {+-} 0.004 for the TPS and Shepard's method. Only slightly inferior results for the smoothed weighting function and the linear approach were achieved. The UQI resulted in a value of Almost-Equal-To 99% for all four interpolation methods. On clinical human data sets, the best results were clearly obtained with the TPS interpolation. The mean contour deviation between the TPS reconstruction and the standard FDK reconstruction improved in the three human cases by 1.52, 1.34, and 1.55 mm. The Dice coefficient showed less sensitivity with respect to variations in the ventricle boundary. Conclusions: In this work, the influence of different motion interpolation methods on left ventricle motion compensated tomographic reconstructions was investigated. The best quantitative reconstruction results of a phantom, a porcine, and human clinical data sets were achieved with the TPS approach. In general, the framework of motion estimation using a surface model and motion interpolation to a dense MVF provides the ability for tomographic reconstruction using a motion compensation technique.

  11. Evaluation of interpolation methods for surface-based motion compensated tomographic reconstruction for cardiac angiographic C-arm data

    International Nuclear Information System (INIS)

    Müller, Kerstin; Schwemmer, Chris; Hornegger, Joachim; Zheng Yefeng; Wang Yang; Lauritsch, Günter; Rohkohl, Christopher; Maier, Andreas K.; Schultz, Carl; Fahrig, Rebecca

    2013-01-01

    experiments showed that TPS interpolation provided the best results. The quantitative results in the phantom experiments showed comparable nRMSE of ≈0.047 ± 0.004 for the TPS and Shepard's method. Only slightly inferior results for the smoothed weighting function and the linear approach were achieved. The UQI resulted in a value of ≈ 99% for all four interpolation methods. On clinical human data sets, the best results were clearly obtained with the TPS interpolation. The mean contour deviation between the TPS reconstruction and the standard FDK reconstruction improved in the three human cases by 1.52, 1.34, and 1.55 mm. The Dice coefficient showed less sensitivity with respect to variations in the ventricle boundary. Conclusions: In this work, the influence of different motion interpolation methods on left ventricle motion compensated tomographic reconstructions was investigated. The best quantitative reconstruction results of a phantom, a porcine, and human clinical data sets were achieved with the TPS approach. In general, the framework of motion estimation using a surface model and motion interpolation to a dense MVF provides the ability for tomographic reconstruction using a motion compensation technique.

  12. Novel computed tomographic chest metrics to detect pulmonary hypertension

    International Nuclear Information System (INIS)

    Chan, Andrew L; Juarez, Maya M; Shelton, David K; MacDonald, Taylor; Li, Chin-Shang; Lin, Tzu-Chun; Albertson, Timothy E

    2011-01-01

    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. 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. 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. 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

  13. Lung surgery assisted by multidetector-row computed tomographic simulation

    International Nuclear Information System (INIS)

    Oizumi, Hiroyuki; Endoh, Makoto; Ota, Hiroshi; Takeda, Shinichi; Suzuki, Jun; Fukaya, Ken; Chiba, Masato; Sadahiro, Mitsuaki

    2009-01-01

    We describe the benefits of lung resection simulation using multidetector computed tomography (MDCT). Since 2004, the 1.0-mm slice digital imaging and communications in medicine (DICOM) server has been used for storing data obtained using 64-row MDCT. We observed that an abnormality could not be visualized from the pleural surface in 10 nodules of 18 lesions undergoing wedge lung resection. These 10 nodules were resected through simulation using a three-dimensional (3D) volume-rendering method by considering parameters such as the position, depth, or distance from the interlobar abnormalities, etc., without the need for any marking methods. For lung lobectomy, identification of the branching structures, diameter, and length of the arteries is useful in selecting the procedure for blood vessel treatment. However, in the initial 10 patients of this series, the preoperative identification of 2 small arterial branches was unsuccessful when this method was used. Therefore, it is important to carefully examine the original data in all 3 views, id est (i.e.), axial, sagittal, and coronal views. The visualization of venous branches in affected segments and intersegmental veins has facilitated the preoperative determination of the anatomical intersegmental plane. We divided the cases of thoracoscopic lung segmentectomy into 3 groups (level 1: simple, level 2: intermediate, and level 3: complex) on the basis of the technical complexity. Only level 1 segmentectomies were performed without MDCT simulation. Further, level 2 and 3 segmentectomies could be successfully performed because of the introduction of MDCT simulation in 25 of 35 patients. Thus, this simulation technique may be useful during a thoracoscopic procedure for lung surgery. (author)

  14. Adult Sail Sign: Radiographic and Computed Tomographic Features

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yu-Jin; Han, Daehee; Koh, Young Hwan; Zo, Joo Hee; Kim, Sang-Hyun; Kim, Deog Kyeom; Lee, Jeong Sang; Moon, Hyeon Jong; Kim, Jong Seung; Chun, Eun Ju; Youn, Byung Jae; Lee, Chang Hyun; Kim, Sam Soo (Dept. of Radiology, Cheil General Hospital, Kwandong Univ. College of Medicine, Seoul (KR))

    2008-02-15

    Background: The sail sign is a well-known radiographic feature of the pediatric chest. This sign can be observed in an adult population as well, but for a different reason. Purpose: To investigate the sail sign appearing in adult chest radiography. Material and Methods: Based on two anecdotal adult cases in which frontal chest radiographs showed the sail sign, we prospectively screened radiographs of 10,238 patients to determine the incidence of the sail sign found in adults in their 40s or older. The cause of the sail sign was assessed using computed tomography (CT). Results: The sail sign was revealed in 10 (seven males, three females; median age 60.6 years) of 10,238 patients. Of these 10 patients with a sail sign on frontal radiographs, eight underwent CT. The frontal radiographs of these 10 patients showed a concave superior margin toward the lung in nine patients, a concave inferior margin in five, and a double-lined inferior margin in three. Lateral radiographs disclosed a focal opacity over the minor fissure in five of six patients, which was either fuzzy (n = 4) or sharp (n = 1) in its upper margin, and was sometimes double lined in the inferior margin (n = 3). CT revealed the anterior mediastinal fat to be the cause of the radiographic sail sign, which stretched laterally from the mediastinum to insinuate into the minor fissure. Conclusion: The incidence of sail sign on adult chest radiographs is about 0.1%. The sign is specific enough to eliminate the need for more sophisticated imaging

  15. Vertebrobasilar system computed tomographic angiography in central vertigo.

    Science.gov (United States)

    Paşaoğlu, Lale

    2017-03-01

    The incidence of vertigo in the population is 20% to 30% and one-fourth of the cases are related to central causes. The aim of this study was to evaluate computed tomography angiography (CTA) findings of the vertebrobasilar system in central vertigo without stroke.CTA and magnetic resonance images of patients with vertigo were retrospectively evaluated. One hundred twenty-nine patients suspected of having central vertigo according to history, physical examination, and otological and neurological tests without signs of infarction on diffusion-weighted magnetic resonance imaging were included in the study. The control group included 120 patients with similar vascular disease risk factors but without vertigo. Vertebral and basilar artery diameters, hypoplasias, exit-site variations of vertebral artery, vertebrobasilar tortuosity, and stenosis of ≥50% detected on CTA were recorded for all patients. Independent-samples t test was used in variables with normal distribution, and Mann-Whitney U test in non-normal distribution. The difference of categorical variable distribution according to groups was analyzed with χ and/or Fisher exact test.Vertebral artery hypoplasia and ≥50% stenosis were seen more often in the vertigo group (P = 0.000, vertigo patients had ≥50% stenosis, 54 (69.2%) had stenosis at V1 segment, 9 (11.5%) at V2 segment, 2 (2.5%) at V3 segment, and 13 (16.6%) at V4 segment. Both vertigo and control groups had similar basilar artery hypoplasia and ≥50% stenosis rates (P = 0.800, >0.05).CTA may be helpful to clarify the association between abnormal CTA findings of vertebral arteries and central vertigo.This article reveals the opportunity to diagnose posterior circulation abnormalities causing central vertigo with a feasible method such as CTA.

  16. Computed tomographic evaluation of abdominal fat in minipigs.

    Science.gov (United States)

    Chang, Jinhwa; Jung, Joohyun; Lee, Hyeyeon; Chang, Dongwoo; Yoon, Junghee; Choi, Mincheol

    2011-03-01

    Computed tomography (CT) exams were conducted to determine the distribution of abdominal fat identified based on the CT number measured in Hounsfield Units (HU) and to measure the volume of the abdominal visceral and subcutaneous fat in minipigs. The relationship between the CT-based fat volumes of several vertebral levels and the entire abdomen and anthropometric data including the sagittal abdominal diameter and waist circumference were evaluated. Moreover, the total fat volumes at the T11, T13, L3, and L5 levels were compared with the total fat volume of the entire abdomen to define the landmark of abdominal fat distribution. Using a single-detector CT, six 6-month-old male minipigs were scanned under general anesthesia. Three radiologists then assessed the HU value of visceral and subcutaneous abdominal fat by drawing the region of interest manually at the T11, T13, L1, L3, and L5 levels. The CT number and abdominal fat determined in this way by the three radiologists was found to be correlated (intra-class coefficient = 0.9). The overall HU ranges for the visceral and subcutaneous fat depots were -147.47 to -83.46 and -131.62 to -90.97, respectively. The total fat volume of the entire abdomen was highly correlated with the volume of abdominal fat at the T13 level (r = 0.97, p abdominal adipose tissue measured at the T13 level using CT is a strong and reliable predictor of total abdominal adipose volume.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    Lee, Kee Hyung; Lee, Seung Chul; Bae, Man Gil; Seo, Heung Suk; Kim, Soon Yong; Lee, Min Ho; Kee, Choon Suhk; Park, Kyung Nam

    1986-01-01

    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.

  19. Adult Sail Sign: Radiographic and Computed Tomographic Features

    International Nuclear Information System (INIS)

    Lee, Yu-Jin; Han, Daehee; Koh, Young Hwan; Zo, Joo Hee; Kim, Sang-Hyun; Kim, Deog Kyeom; Lee, Jeong Sang; Moon, Hyeon Jong; Kim, Jong Seung; Chun, Eun Ju; Y oun, Byung Jae; Lee, Chang Hyun; Kim, Sam Soo

    2008-01-01

    Background: The sail sign is a well-known radiographic feature of the pediatric chest. This sign can be observed in an adult population as well, but for a different reason. Purpose: To investigate the sail sign appearing in adult chest radiography. Material and Methods: Based on two anecdotal adult cases in which frontal chest radiographs showed the sail sign, we prospectively screened radiographs of 10,238 patients to determine the incidence of the sail sign found in adults in their 40s or older. The cause of the sail sign was assessed using computed tomography (CT). Results: The sail sign was revealed in 10 (seven males, three females; median age 60.6 years) of 10,238 patients. Of these 10 patients with a sail sign on frontal radiographs, eight underwent CT. The frontal radiographs of these 10 patients showed a concave superior margin toward the lung in nine patients, a concave inferior margin in five, and a double-lined inferior margin in three. Lateral radiographs disclosed a focal opacity over the minor fissure in five of six patients, which was either fuzzy (n = 4) or sharp (n = 1) in its upper margin, and was sometimes double lined in the inferior margin (n = 3). CT revealed the anterior mediastinal fat to be the cause of the radiographic sail sign, which stretched laterally from the mediastinum to insinuate into the minor fissure. Conclusion: The incidence of sail sign on adult chest radiographs is about 0.1%. The sign is specific enough to eliminate the need for more sophisticated imaging

  20. Hepatocellular carcinoma with bile duct involvement : computed Tomographic (CT) findings

    International Nuclear Information System (INIS)

    Lee, Joon Woo; Han, Joon Koo; Kim, Tae Kyoung; And others

    2000-01-01

    To describe the radiologic features of computed tomography (CT) in hepatocellular carcinoma (HCC) with bile duct involvement. We retrospectively analyzed the two phase spiral CT findings of 31 patients in whom HCC with bile duct invasion (n=3D28) or compression (n=3D3), was diagnosed. Eight of these underwent follow up CT after transarterial chemoembolization. We analyzed the size, type, location, enhancement pattern, and lipiodol retention of parenchymal and intraductal masses, as well as their lymphadenopathy. In all patients with bile duct invasion, single or multiple masses were demonstrated in the bile ducts. Intraductal masses showed the same enhancement characteristics as the parenchymal mass (kappa 0.550, p less than 0.001), and were contiguous to this mass. In 14 of 28 patients, intraductal masses filled the peripheral intrahepatic bile ducts and extended to the common bile ducts. In the other 14, the parenchymal mass extended to the area of the porta hepatis and then directly invaded the large ducts. In nine of the 28 patients, there was a hypoattenuated cleft between the intraductal mass and ductal wall. In six, a parenchymal mass was not apparent (n=3D2), or was smaller than 2cm (n=3D4). In five of eight patients (62.5%), follow-up CT after transarterial chemoembolization showed compact or partial lipiodol retention within the intraductal mass. In patients with bile duct compression, perihilar lymph nodes were noted along with the dilated intrahepatic duct but no intra ductal mass was demonstrated in the duct. Hepatocellular carcinomas cause bile duct dilatation either by direct invasion or by extrinsic compression of the bile duct with surrounding enlarged nodes. For the diagnosis of this condition, CT is helpful. (author)

  1. Computed Tomographic Findings of Acute Carbon Monoxide Posioning

    International Nuclear Information System (INIS)

    Park, Young Keun; Won, Hee Sun; Lee, Seung Ro; Hahm, Chang Kok

    1983-01-01

    Carbon monoxide (CO) is a kind of frequent toxic gas around our living lives, for common use of briquets as fuel, and its pathologic effect has been known due to mainly hypoxia and direct cytotoxicity in some part to almost all organs, especially to the brain and heart. Some authors have reported pathologic and anatomic changes of the acute of poisoning, although in a few cases, that bilaterally symmetrical lesions of the globs pallidus or cerebral white matter regarded as typical. After using computed tomography (CT), those findings have been discovered more easily and accurately. Authors analysed CT findings of 32 cases, who had a history of acute CO poisoning and performed CT at Hanyang University Hospital from May 1970 to June 1983. The results were as follows: 1. Of all 32 cases with CT scan, low density lesions were demonstrated in 28 cases (88%) and others were hemorrhage and calcified in 2(6%), respectively. 2. All lesions were seen as bilaterally symmetrical, except 2 cases of hemorrhage and 1 of low density. 3. Of all 28 cases of the low densities, 15 cases(53.6%) were located in the globs pallidus, 10(35.7%) in the cerebral white matter and 3(10.7%) in both of them. 4. Of all 113 cases of the low density lesions in the cerebral white matter, common locations were in the frontal and parietal lobes (65.6%), and more in frontal (40.6%). 5. Of all 113 cases of low density lesions in the cerebral white matter, cases of involving all of the lobes were found in only 4. 6. All of 2 cases of the calcified lesions were seen at both sides of the globs pallidus, symmetrically. 7. All of 2 cases of the hemorrhage were seen at thalamus, ventricles and head of caudate nucleus, and these locations were different from those of the low densities or calcifications.

  2. High resolution computed tomographic features of pulmonary alveolar microlithiasis

    International Nuclear Information System (INIS)

    Deniz, Omer; Ors, Fatih; Tozkoparan, Ergun; Ozcan, Ayhan; Gumus, Seyfettin; Bozlar, Ugur; Bilgic, Hayati; Ekiz, Kudret; Demirci, Necmettin

    2005-01-01

    Background: Pulmonary alveolar microlithiasis (PAM) is a rare, chronic lung disease with unknown etiology and with a nonuniform clinical course. Nonuniformity of clinical course might be related to the degree of pulmonary parenchymal alterations, which can be revealed with high resolution computed tomography (HRCT). However, HRCT findings of PAM were not fully described in the current literature. Aim: The aim of this study was to interpret and to contribute to describe HRCT findings of PAM and to investigate a correlation between profusion of micro nodules (MN) and pulmonary parenchymal alterations in patients with PAM. Material and methods: Ten male patients with PAM (mean age: 22 ± 3.2) were included into the study. HRCT images were assessed for patterns, distribution, and profusion of pulmonary abnormalities. Dividing the lungs into three zones, profusion of abnormalities was assessed. A profusion score (1-4) was given and the scores of each zone were then summed to obtain a global profusion score for HRCT ranging from 0 to 12. Also a parenchymal alteration score (PAS) was defined with respect to profusion of abnormalities. Chest X-rays were also scored. Results: All of ten patients with PAM had findings of interstitial lung disease in varying degrees on their HRCTs. HRCT findings of patients with PAM were as following: MN, parenchymal bands (PB), ground glass opacity (GGO) and, sub pleural interstitial thickening (SPIT) in 10 patients; interlobular septal thickening (ILST), in 9 patients; paraseptal emphysema (PSA) in 8 patients; centrilobular emphysema (CLA) in 7 patients; bronchiectasis (BE), confluent micro nodules (CMN) in 6 patients; peri bronchovascular interstitial thickening (PBIT) in 5 patients; panacinar emphysema (PANAA) in 3 patients; pleural calcification (PC) in 2 patients. A significant correlation between MN scores and PAS (r = 0.68, p = 0.031, MN scores and GGO scores (r = 0.69, p = 0.027) and, MN scores and CLA scores (r = 0.67, p = 0

  3. A Novel Quantitative Computed Tomographic Analysis Suggests How Sirolimus Stabilizes Progressive Air Trapping in Lymphangioleiomyomatosis.

    Science.gov (United States)

    Argula, Rahul G; Kokosi, Maria; Lo, Pechin; Kim, Hyun J; Ravenel, James G; Meyer, Cristopher; Goldin, Jonathan; Lee, Hye-Seung; Strange, Charlie; McCormack, Francis X

    2016-03-01

    The Multicenter International Lymphangioleiomyomatosis Efficacy and Safety of Sirolimus (MILES) trial demonstrated that sirolimus stabilized lung function and improved measures of functional performance and quality of life in patients with lymphangioleiomyomatosis. The physiologic mechanisms of these beneficial actions of sirolimus are incompletely understood. To prospectively determine the longitudinal computed tomographic lung imaging correlates of lung function change in MILES patients treated with placebo or sirolimus. We determined the baseline to 12-month change in computed tomographic image-derived lung volumes and the volume of the lung occupied by cysts in the 31 MILES participants (17 in sirolimus group, 14 in placebo group) with baseline and 12-month scans. There was a trend toward an increase in median expiratory cyst volume percentage in the placebo group and a reduction in the sirolimus group (+2.68% vs. +0.97%, respectively; P = 0.10). The computed tomographic image-derived residual volume and the ratio of residual volume to total lung capacity increased more in the placebo group than in the sirolimus group (+214.4 ml vs. +2.9 ml [P = 0.054] and +0.05 ml vs. -0.01 ml [P = 0.0498], respectively). A Markov transition chain analysis of respiratory cycle cyst volume changes revealed greater dynamic variation in the sirolimus group than in the placebo group at the 12-month time point. Collectively, these data suggest that sirolimus attenuates progressive gas trapping in lymphangioleiomyomatosis, consistent with a beneficial effect of the drug on airflow obstruction. We speculate that a reduction in lymphangioleiomyomatosis cell burden around small airways and cyst walls alleviates progressive airflow limitation and facilitates cyst emptying.

  4. Craniofacial fibrous dysplasia: Report of a case using computed tomographic scan diagnosis

    Directory of Open Access Journals (Sweden)

    Nikhil Diwan

    2013-01-01

    Full Text Available Fibro-osseous lesions are benign mesenchymal tumors in which mineralized tissue, blood vessels, and giant cells, in varying proportions, replace normal bone. Although this group of lesions includes reactive lesions, harmatomas, and neoplasms, they cannot be distinguished only on the basis of the histopathology which can only confirm their common fibro-osseous nature. Definitive diagnosis requires thorough radiological evaluation. Computed tomographic images of craniofacial fibrous dysplasia on bone windows may be helpful and allow precise pre-operative diagnosis and surgical planning.

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

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

    International Nuclear Information System (INIS)

    Caon, M.

    2001-01-01

    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. Copyright (2001) Australasian College of Physical Scientists and Engineers in Medicine

  7. Proton computed tomography images with algebraic reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Bruzzi, M. [Physics and Astronomy Department, University of Florence, Florence (Italy); Civinini, C.; Scaringella, M. [INFN - Florence Division, Florence (Italy); Bonanno, D. [INFN - Catania Division, Catania (Italy); Brianzi, M. [INFN - Florence Division, Florence (Italy); Carpinelli, M. [INFN - Laboratori Nazionali del Sud, Catania (Italy); Chemistry and Pharmacy Department, University of Sassari, Sassari (Italy); Cirrone, G.A.P.; Cuttone, G. [INFN - Laboratori Nazionali del Sud, Catania (Italy); Presti, D. Lo [INFN - Catania Division, Catania (Italy); Physics and Astronomy Department, University of Catania, Catania (Italy); Maccioni, G. [INFN – Cagliari Division, Cagliari (Italy); Pallotta, S. [INFN - Florence Division, Florence (Italy); Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Florence (Italy); SOD Fisica Medica, Azienda Ospedaliero-Universitaria Careggi, Firenze (Italy); Randazzo, N. [INFN - Catania Division, Catania (Italy); Romano, F. [INFN - Laboratori Nazionali del Sud, Catania (Italy); Sipala, V. [INFN - Laboratori Nazionali del Sud, Catania (Italy); Chemistry and Pharmacy Department, University of Sassari, Sassari (Italy); Talamonti, C. [INFN - Florence Division, Florence (Italy); Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Florence (Italy); SOD Fisica Medica, Azienda Ospedaliero-Universitaria Careggi, Firenze (Italy); Vanzi, E. [Fisica Sanitaria, Azienda Ospedaliero-Universitaria Senese, Siena (Italy)

    2017-02-11

    A prototype of proton Computed Tomography (pCT) system for hadron-therapy has been manufactured and tested in a 175 MeV proton beam with a non-homogeneous phantom designed to simulate high-contrast material. BI-SART reconstruction algorithms have been implemented with GPU parallelism, taking into account of most likely paths of protons in matter. Reconstructed tomography images with density resolutions r.m.s. down to ~1% and spatial resolutions <1 mm, achieved within processing times of ~15′ for a 512×512 pixels image prove that this technique will be beneficial if used instead of X-CT in hadron-therapy.

  8. Optical Computed-Tomographic Microscope for Three-Dimensional Quantitative Histology

    Directory of Open Access Journals (Sweden)

    Ravil Chamgoulov

    2004-01-01

    Full Text Available A novel optical computed‐tomographic microscope has been developed allowing quantitative three‐dimensional (3D imaging and analysis of fixed pathological material. Rather than a conventional two‐dimensional (2D image, the instrument produces a 3D representation of fixed absorption‐stained material, from which quantitative histopathological features can be measured more accurately. The accurate quantification of these features is critically important in disease diagnosis and the clinical classification of cancer. The system consists of two high NA objective lenses, a light source, a digital spatial light modulator (DMD, by Texas Instrument, an x–y stage, and a CCD detector. The DMD, positioned at the back pupil‐plane of the illumination objective, is employed to illuminate the specimen with parallel rays at any desired angle. The system uses a modification of the convolution backprojection algorithm for reconstruction. In contrast to fluorescent images acquired by a confocal microscope, this instrument produces 3D images of absorption stained material. Microscopic 3D volume reconstructions of absorption‐stained cells have been demonstrated. Reconstructed 3D images of individual cells and tissue can be cut virtually with the distance between the axial slices less than 0.5 μm.

  9. Tomographic apparatus for reconstructing planar slices from non-absorbed and non-scattered radiation

    International Nuclear Information System (INIS)

    1980-01-01

    After briefly reviewing the history of computerised tomography, the deficiencies inherent in the various methods that have been adopted are discussed, e.g. slow data collection time, blurring of images and poor spatial resolution. Tomographic apparatus and processing methods are then described which can overcome these problems. The apparatus consists of a fan-shaped source of X-rays and a detector array which both rotate around the patient being examined. The data reduction process is derived in great detail; it is claimed that digital processing using convolution techniques is much faster than conventional methods. (U.K.)

  10. Seismic tomographic constraints on plate-tectonic reconstructions of Nazca subduction under South America since late Cretaceous (˜80 Ma)

    Science.gov (United States)

    Chen, Y. W.; Wu, J.; Suppe, J.

    2017-12-01

    Global seismic tomography has provided new and increasingly higher resolution constraints on subducted lithospheric remnants in terms of their position, depth, and volumes. In this study we aim to link tomographic slab anomalies in the mantle under South America to Andean geology using methods to unfold (i.e. structurally restore) slabs back to earth surface and input them to globally consistent plate reconstructions (Wu et al., 2016). The Andean margin of South America has long been interpreted as a classic example of a continuous subduction system since early Jurassic or later. However, significant gaps in Andean plate tectonic reconstructions exist due to missing or incomplete geology from extensive Nazca-South America plate convergence (i.e. >5000 km since 80 Ma). We mapped and unfolded the Nazca slab from global seismic tomography to produce a quantitative plate reconstruction of the Andes back to the late Cretaceous 80 Ma. Our plate model predicts the latest phase of Nazca subduction began in the late Cretaceous subduction after a 100 to 80 Ma plate reorganization, which is supported by Andean geology that indicates a margin-wide compressional event at the mid-late Cretaceous (Tunik et al., 2010). Our Andean plate tectonic reconstructions predict the Andean margin experienced periods of strike-slip/transtensional and even divergent plate tectonics between 80 to 55 Ma. This prediction is roughly consistent with the arc magmatism from northern Chile between 20 to 36°S that resumed at 80 Ma after a magmatic gap. Our model indicates the Andean margin only became fully convergent after 55 Ma. We provide additional constraints on pre-subduction Nazca plate paleogeography by extracting P-wave velocity perturbations within our mapped slab surfaces following Wu et al. (2016). We identified localized slow anomalies within our mapped Nazca slab that apparently show the size and position of the subducted Nazca ridge, Carnegie ridge and the hypothesized Inca plateau

  11. Computed Tomographic Analysis of Ventral Atlantoaxial Optimal Safe Implantation Corridors in 27 Dogs.

    Science.gov (United States)

    Leblond, Guillaume; Gaitero, Luis; Moens, Noel M M; Zur Linden, Alex; James, Fiona M K; Monteith, Gabrielle J; Runciman, John

    2017-11-01

    Objectives  Ventral atlantoaxial stabilization techniques are challenging surgical procedures in dogs. Available surgical guidelines are based upon subjective anatomical landmarks, and limited radiographic and computed tomographic data. The aims of this study were (1) to provide detailed anatomical descriptions of atlantoaxial optimal safe implantation corridors to generate objective recommendations for optimal implant placements and (2) to compare anatomical data obtained in non-affected Toy breed dogs, affected Toy breed dogs suffering from atlantoaxial instability and non-affected Beagle dogs. Methods  Anatomical data were collected from a prospectively recruited population of 27 dogs using a previously validated method of optimal safe implantation corridor analysis using computed tomographic images. Results  Optimal implant positions and three-dimensional numerical data were generated successfully in all cases. Anatomical landmarks could be used to generate objective definitions of optimal insertion points which were applicable across all three groups. Overall the geometrical distribution of all implant sites was similar in all three groups with a few exceptions. Clinical Significance  This study provides extensive anatomical data available to facilitate surgical planning of implant placement for atlantoaxial stabilization. Our data suggest that non-affected Toy breed dogs and non-affected Beagle dogs constitute reasonable research models to study atlantoaxial stabilization constructs. Schattauer GmbH Stuttgart.

  12. Development of x-ray computed tomographic scanner for iron and steel

    International Nuclear Information System (INIS)

    Taguchi, Isamu; Nakamura, Shigeo.

    1985-01-01

    X-ray computed tomography is extensively used in medicine, but has rarely been applied to non-medical purposes. Steel specimens pose particularly difficult problems-very poor transmission of X-rays and the need for high resolving capability. There has thus been no effective tomographic method of examining steel specimens. Due to the growing need for non-destructive, non-contact methods for observing and analyzing the internal conditions of steel microscopically, however, we have developed an X-ray Computed Tomographic Scanner for Steel (CTS) system, specifically for examination of steel specimens. Its major specifications and functions are as follows. Type: the second-generation CT, 8-channels, Scanning method: 6 0 revolution, 30-times traversing, Slice width: 0.5 mm, Resolving capability: 0.25 x 0.25 mm, X-ray source: 420 kV, 3 mA, X-ray detector: BGO scintillator, Standard specimen shape: 50 mm dia., 100 mm high, Measuring time: 10.5 min. Porosity of a stainless steel (SUS 304) bloom was examined three-dimensionally by the CTS system. Corrosion procedure of a steel slab was also examined. (author)

  13. Synchronized multiartifact reduction with tomographic reconstruction (SMART-RECON): A statistical model based iterative image reconstruction method to eliminate limited-view artifacts and to mitigate the temporal-average artifacts in time-resolved CT.

    Science.gov (United States)

    Chen, Guang-Hong; Li, Yinsheng

    2015-08-01

    In x-ray computed tomography (CT), a violation of the Tuy data sufficiency condition leads to limited-view artifacts. In some applications, it is desirable to use data corresponding to a narrow temporal window to reconstruct images with reduced temporal-average artifacts. However, the need to reduce temporal-average artifacts in practice may result in a violation of the Tuy condition and thus undesirable limited-view artifacts. In this paper, the authors present a new iterative reconstruction method, synchronized multiartifact reduction with tomographic reconstruction (SMART-RECON), to eliminate limited-view artifacts using data acquired within an ultranarrow temporal window that severely violates the Tuy condition. In time-resolved contrast enhanced CT acquisitions, image contrast dynamically changes during data acquisition. Each image reconstructed from data acquired in a given temporal window represents one time frame and can be denoted as an image vector. Conventionally, each individual time frame is reconstructed independently. In this paper, all image frames are grouped into a spatial-temporal image matrix and are reconstructed together. Rather than the spatial and/or temporal smoothing regularizers commonly used in iterative image reconstruction, the nuclear norm of the spatial-temporal image matrix is used in SMART-RECON to regularize the reconstruction of all image time frames. This regularizer exploits the low-dimensional structure of the spatial-temporal image matrix to mitigate limited-view artifacts when an ultranarrow temporal window is desired in some applications to reduce temporal-average artifacts. Both numerical simulations in two dimensional image slices with known ground truth and in vivo human subject data acquired in a contrast enhanced cone beam CT exam have been used to validate the proposed SMART-RECON algorithm and to demonstrate the initial performance of the algorithm. Reconstruction errors and temporal fidelity of the reconstructed

  14. Fully 3D tomographic reconstruction by Monte Carlo simulation of the system matrix in preclinical PET with iodine 124

    International Nuclear Information System (INIS)

    Moreau, Matthieu

    2014-01-01

    Immuno-PET imaging can be used to assess the pharmacokinetic in radioimmunotherapy. When using iodine-124, PET quantitative imaging is limited by physics-based degrading factors within the detection system and the object, such as the long positron range in water and the complex spectrum of gamma photons. The objective of this thesis was to develop a fully 3D tomographic reconstruction method (S(MC)2PET) using Monte Carlo simulations for estimating the system matrix, in the context of preclinical imaging with iodine-124. The Monte Carlo simulation platform GATE was used for that respect. Several complexities of system matrices were calculated, with at least a model of the PET system response function. Physics processes in the object was either neglected or taken into account using a precise or a simplified object description. The impact of modelling refinement and statistical variance related to the system matrix elements was evaluated on final reconstructed images. These studies showed that a high level of complexity did not always improve qualitative and quantitative results, owing to the high-variance of the associated system matrices. (author)

  15. Wavefront reconstruction using computer-generated holograms

    Science.gov (United States)

    Schulze, Christian; Flamm, Daniel; Schmidt, Oliver A.; Duparré, Michael

    2012-02-01

    We propose a new method to determine the wavefront of a laser beam, based on modal decomposition using computer-generated holograms (CGHs). Thereby the beam under test illuminates the CGH with a specific, inscribed transmission function that enables the measurement of modal amplitudes and phases by evaluating the first diffraction order of the hologram. Since we use an angular multiplexing technique, our method is innately capable of real-time measurements of amplitude and phase, yielding the complete information about the optical field. A measurement of the Stokes parameters, respectively of the polarization state, provides the possibility to calculate the Poynting vector. Two wavefront reconstruction possibilities are outlined: reconstruction from the phase for scalar beams and reconstruction from the Poynting vector for inhomogeneously polarized beams. To quantify single aberrations, the reconstructed wavefront is decomposed into Zernike polynomials. Our technique is applied to beams emerging from different kinds of multimode optical fibers, such as step-index, photonic crystal and multicore fibers, whereas in this work results are exemplarily shown for a step-index fiber and compared to a Shack-Hartmann measurement that serves as a reference.

  16. Experimental device, corresponding forward model and processing of the experimental data using wavelet analysis for tomographic image reconstruction applied to eddy current nondestructive evaluation

    International Nuclear Information System (INIS)

    Joubert, P.Y.; Madaoui, N.

    1999-01-01

    In the context of eddy current non destructive evaluation using a tomographic image reconstruction process, the success of the reconstruction depends not only on the choice of the forward model and of the inversion algorithms, but also on the ability to extract the pertinent data from the raw signal provided by the sensor. We present in this paper, an experimental device designed for imaging purposes, the corresponding forward model, and a pre-processing of the experimental data using wavelet analysis. These three steps implemented with an inversion algorithm, will allow in the future to perform image reconstruction of 3-D flaws. (authors)

  17. Image-guided microneurosurgical management of small cerebral arteriovenous malformations: the value of navigated computed tomographic angiography

    International Nuclear Information System (INIS)

    Coenen, V.A.; Reinges, M.H.T.; Gilsbach, J.M.; Rohde, V.; Dammert, S.; Mull, M.

    2005-01-01

    In small arteriovenous malformations (AVM) with large hematomas, surgery remains the main therapeutic option. However, intraoperative identification of the AVM, feeders, and draining veins could be difficult in the environment of substantial intracerebral blood. In those selected cases, we use navigated computed tomographic angiography (CTA) for the microneurosurgical management. It is our objective to report our initial experiences. Prior to operation a conventional CTA with superficial skin fiducials placed on a patient's head was acquired for diagnostic and neuronavigation purposes. Image data were transferred to a neuronavigation device with integrated volume rendering capacities which allows a three-dimensional reconstruction of the vascular tree and the AVM to be created. In all patients the AVM was removed successfully after having been localized with CTA-based neuronavigation. Navigated CTA is helpful for the operative management of small AVMs with large hematomas. The technique allows feeding arteries to be distinguished from draining veins thereby allowing the nidus of the AVM to be identified despite the presence of substantial intracerebral blood. CTA can be easily implemented into commercial neuronavigation systems. (orig.)

  18. Advances in tomographic PIV

    NARCIS (Netherlands)

    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

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

    Science.gov (United States)

    Kurthukoti, Ameet J; Sharma, Pranjal; Swamy, Dinesh Francis; Shashidara, R; Swamy, Elaine Barretto

    2015-01-01

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

  20. Validation of Spherically Symmetric Inversion by Use of a Tomographically Reconstructed Three-Dimensional Electron Density of the Solar Corona

    Science.gov (United States)

    Wang, Tongjiang; Davila, Joseph M.

    2014-01-01

    Determining the coronal electron density by the inversion of white-light polarized brightness (pB) measurements by coronagraphs is a classic problem in solar physics. An inversion technique based on the spherically symmetric geometry (spherically symmetric inversion, SSI) was developed in the 1950s and has been widely applied to interpret various observations. However, to date there is no study of the uncertainty estimation of this method. We here present the detailed assessment of this method using a three-dimensional (3D) electron density in the corona from 1.5 to 4 solar radius as a model, which is reconstructed by a tomography method from STEREO/COR1 observations during the solar minimum in February 2008 (Carrington Rotation, CR 2066).We first show in theory and observation that the spherically symmetric polynomial approximation (SSPA) method and the Van de Hulst inversion technique are equivalent. Then we assess the SSPA method using synthesized pB images from the 3D density model, and find that the SSPA density values are close to the model inputs for the streamer core near the plane of the sky (POS) with differences generally smaller than about a factor of two; the former has the lower peak but extends more in both longitudinal and latitudinal directions than the latter. We estimate that the SSPA method may resolve the coronal density structure near the POS with angular resolution in longitude of about 50 deg. Our results confirm the suggestion that the SSI method is applicable to the solar minimum streamer (belt), as stated in some previous studies. In addition, we demonstrate that the SSPA method can be used to reconstruct the 3D coronal density, roughly in agreement with the reconstruction by tomography for a period of low solar activity (CR 2066). We suggest that the SSI method is complementary to the 3D tomographic technique in some cases, given that the development of the latter is still an ongoing research effort.

  1. The Role of Bone Subtraction Computed Tomographic Angiography in Determining Intracranial Aneurysms in Non-Traumatic Subarachnoid Hemorrhage

    International Nuclear Information System (INIS)

    Kayhan, Aysegul; Koc, Osman; Keskin, Suat; Keskin, Fatih

    2014-01-01

    The presence of blood in the subarachnoid space is an acute pathology with a serious risk of death and complications. The most common etiology (approximately 80%) is intracranial aneurysm. The aim of this study was to assess the role of bone subtracted computed tomographic angiography (BSCTA), a novel and noninvasive method for determining and characterizing intracranial aneurysms. Sixty consecutive patients with clinically suspected non-traumatic subarachnoid hemorrhage (SAH) were considered to enter the study. The subtraction quality was inadequate in ten patients; thus, they were excluded, leaving 50 patients (84.4%) in the study. Bone subtracted and non-subtracted 3D images were obtained from the BSCTA raw data sets. All images obtained by digital subtraction angiography (DSA), BSCTA, and computed tomographic angiography (CTA) were evaluated for the presence or absence of an aneurysm and the location, minimal sac diameter, and neck size ratio of the aneurysm. DSA was considered as the gold standard during the evaluation of the data. Of the 50 patients who participated in this study, 11 had no aneurysms as determined by both CTA and DSA. Examination of the remaining 39 patients revealed the presence of 51 aneurysms. While 3D-CTA could not detect six aneurysms that were located in the base of the skull, 3D-BSCTA easily detected them. Moreover, five aneurysms were only partially detected by 3D-CTA. According to this data, the sensitivity of 3D-BSCTA and 3D-CTA was calculated as 98% and 86.3%, respectively; the specificity was calculated as 100% and 90.9%, respectively, per aneurysm; and the sensitivity of 100% for 3D-BSCTA and 98% for 3D-CTA was achieved by using combined images with multi-planar reconstruction (MPR) and maximum intensity projection (MIP). BSCTA detected and characterized the aneurysms as well as DSA, and BSCTA and DSA gave concordant results in detecting aneurysms. BSCTA is easily accessible, less time consuming, and most importantly, a non

  2. The Role of Bone Subtraction Computed Tomographic Angiography in Determining Intracranial Aneurysms in Non-Traumatic Subarachnoid Hemorrhage

    Science.gov (United States)

    Kayhan, Aysegul; Koc, Osman; Keskin, Suat; Keskin, Fatih

    2014-01-01

    Background: The presence of blood in the subarachnoid space is an acute pathology with a serious risk of death and complications. The most common etiology (approximately 80%) is intracranial aneurysm. Objectives: The aim of this study was to assess the role of bone subtracted computed tomographic angiography (BSCTA), a novel and noninvasive method for determining and characterizing intracranial aneurysms. Patients and Methods: Sixty consecutive patients with clinically suspected non-traumatic subarachnoid hemorrhage (SAH) were considered to enter the study. The subtraction quality was inadequate in ten patients; thus, they were excluded, leaving 50 patients (84.4%) in the study. Bone subtracted and non-subtracted 3D images were obtained from the BSCTA raw data sets. All images obtained by digital subtraction angiography (DSA), BSCTA, and computed tomographic angiography (CTA) were evaluated for the presence or absence of an aneurysm and the location, minimal sac diameter, and neck size ratio of the aneurysm. DSA was considered as the gold standard during the evaluation of the data. Results: Of the 50 patients who participated in this study, 11 had no aneurysms as determined by both CTA and DSA. Examination of the remaining 39 patients revealed the presence of 51 aneurysms. While 3D-CTA could not detect six aneurysms that were located in the base of the skull, 3D-BSCTA easily detected them. Moreover, five aneurysms were only partially detected by 3D-CTA. According to this data, the sensitivity of 3D-BSCTA and 3D-CTA was calculated as 98% and 86.3%, respectively; the specificity was calculated as 100% and 90.9%, respectively, per aneurysm; and the sensitivity of 100% for 3D-BSCTA and 98% for 3D-CTA was achieved by using combined images with multi-planar reconstruction (MPR) and maximum intensity projection (MIP). BSCTA detected and characterized the aneurysms as well as DSA, and BSCTA and DSA gave concordant results in detecting aneurysms. Conclusions: BSCTA is

  3. Influence of using a single facial vein as outflow in full-face transplantation: A three-dimensional computed tomographic study.

    Science.gov (United States)

    Rodriguez-Lorenzo, Andres; Audolfsson, Thorir; Wong, Corrine; Cheng, Angela; Arbique, Gary; Nowinski, Daniel; Rozen, Shai

    2015-10-01

    The aim of this study was to evaluate the contribution of a single unilateral facial vein in the venous outflow of total-face allograft using three-dimensional computed tomographic imaging techniques to further elucidate the mechanisms of venous complications following total-face transplant. Full-face soft-tissue flaps were harvested from fresh adult human cadavers. A single facial vein was identified and injected distally to the submandibular gland with a radiopaque contrast (barium sulfate/gelatin mixture) in every specimen. Following vascular injections, three-dimensional computed tomographic venographies of the faces were performed. Images were viewed using TeraRecon Software (Teracon, Inc., San Mateo, CA, USA) allowing analysis of the venous anatomy and perfusion in different facial subunits by observing radiopaque filling venous patterns. Three-dimensional computed tomographic venographies demonstrated a venous network with different degrees of perfusion in subunits of the face in relation to the facial vein injection side: 100% of ipsilateral and contralateral forehead units, 100% of ipsilateral and 75% of contralateral periorbital units, 100% of ipsilateral and 25% of contralateral cheek units, 100% of ipsilateral and 75% of contralateral nose units, 100% of ipsilateral and 75% of contralateral upper lip units, 100% of ipsilateral and 25% of contralateral lower lip units, and 50% of ipsilateral and 25% of contralateral chin units. Venographies of the full-face grafts revealed better perfusion in the ipsilateral hemifaces from the facial vein in comparison with the contralateral hemifaces. Reduced perfusion was observed mostly in the contralateral cheek unit and contralateral lower face including the lower lip and chin units. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  4. Relaxed Simultaneous Tomographic Reconstruction and Segmentation with Class Priors for Poisson Noise

    DEFF Research Database (Denmark)

    Romanov, Mikhail; Dahl, Anders Bjorholm; Dong, Yiqiu

    : our new algorithm can handle Poisson noise in the data, and it can solve much larger problems since it does not store the matrix. We formulate this algorithm and test it on artificial test problems. Our results show that the algorithm performs well, and that we are able to produce reconstructions...

  5. A Convex Reconstruction Model for X-ray Tomographic Imaging with Uncertain Flat-fields

    DEFF Research Database (Denmark)

    Aggrawal, Hari Om; Andersen, Martin Skovgaard; Rose, Sean

    2018-01-01

    has a negligible effect on the reconstruction quality. However, in time- or dose-limited applications such as dynamic CT, this uncertainty may cause severe and systematic artifacts known as ring artifacts. By carefully modeling the measurement process and by taking uncertainties into account, we...

  6. THREE-DIMENSIONAL TOMOGRAPHIC RECONSTRUCTION OF FOUNDRY ARTICLES ON LIMITED MODEL AND EXPERIMENTAL DATA

    Directory of Open Access Journals (Sweden)

    V. L. Vengrinovich

    2009-01-01

    Full Text Available The ways of overcoming of lack of source information, The ways of overcoming of lack of source information, allowing to reduce energy of primary X-radiation, necessary  for radiography and to provide high quality of reconstruction, are offered.

  7. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    Details are given of a tomographic scanning apparatus, with particular reference to a multiplexer slip ring means for receiving output from the detectors and enabling interfeed to the image reconstruction station. (U.K.)

  8. Computed tomographic and cross-sectional anatomy of the normal pacu (Colossoma macroponum).

    Science.gov (United States)

    Carr, Alaina; Weber, E P Scott; Murphy, Chris J; Zwingenberger, Alison

    2014-03-01

    The purpose of this study was to compare and define the normal cross-sectional gross and computed tomographic (CT) anatomy for a species of boney fish to better gain insight into the use of advanced diagnostic imaging for future clinical cases. The pacu (Colossoma macropomum) was used because of its widespread presence in the aquarium trade, its relatively large body size, and its importance in the research and aquaculture settings. Transverse 0.6-mm CT images of three cadaver fish were obtained and compared to corresponding frozen cross sections of the fish. Relevant anatomic structures were identified and labeled at each level; the Hounsfield unit density of major organs was established. The images presented good anatomic detail and provide a reference for future research and clinical investigation.

  9. Comparison between computed tomographic and surgical findings in nine large-breed dogs with lumbosacral stenosis

    International Nuclear Information System (INIS)

    Jones, J.C.; Sorjonen, D.C.; Simpson, S.T.; Coates, J.R.; Lenz, S.D.; Hathcock, J.T.; Agee, M.W.; Bartels, J.E.

    1996-01-01

    In a three-year prospective study, computed tomographic (CT) and surgical findings were compared for nine large breed dogs with lumbosacral stenosis. Surgically-excised tissue was examined histologically in seven dogs and additional necropsy evaluation was performed in one dog. The CT abnormalities observed at sites of confirmed cauda equina compression were: loss of epidural fat, increased soft tissue opacity, bulging of the intervertebral disc margin, spondylosis, thecal sac displacement, narrowed intervertebral foramen, narrowed vertebral canal, thickened articular process, articular process subluxation, articular process osteophyte, and telescoped sacral lamina. The CT characteristics of lumbosacral degenerative disease and discospondylitis were similar to those described in humans. In three dogs, CT findings at the site of cauda equina compression were consistent with congenital or developmental spinal stenosis, but the method of surgical exposure precluded confirmation. Epidural fibrosis (eight dogs) and multi-level CT abnormalities (six dogs) were identified but the cause(s) and significance were unknown

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  11. Relationship of Hypertension to Coronary Atherosclerosis and Cardiac Events in Patients With Coronary Computed Tomographic Angiography.

    Science.gov (United States)

    Nakanishi, Rine; Baskaran, Lohendran; Gransar, Heidi; Budoff, Matthew J; Achenbach, Stephan; Al-Mallah, Mouaz; Cademartiri, Filippo; Callister, Tracy Q; Chang, Hyuk-Jae; Chinnaiyan, Kavitha; Chow, Benjamin J W; DeLago, Augustin; Hadamitzky, Martin; Hausleiter, Joerg; Cury, Ricardo; Feuchtner, Gudrun; Kim, Yong-Jin; Leipsic, Jonathon; Kaufmann, Philipp A; Maffei, Erica; Raff, Gilbert; Shaw, Leslee J; Villines, Todd C; Dunning, Allison; Marques, Hugo; Pontone, Gianluca; Andreini, Daniele; Rubinshtein, Ronen; Bax, Jeroen; Jones, Erica; Hindoyan, Niree; Gomez, Millie; Lin, Fay Y; Min, James K; Berman, Daniel S

    2017-08-01

    Hypertension is an atherosclerosis factor and is associated with cardiovascular risk. We investigated the relationship between hypertension and the presence, extent, and severity of coronary atherosclerosis in coronary computed tomographic angiography and cardiac events risk. Of 17 181 patients enrolled in the CONFIRM registry (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry) who underwent ≥64-detector row coronary computed tomographic angiography, we identified 14 803 patients without known coronary artery disease. Of these, 1434 hypertensive patients were matched to 1434 patients without hypertension. Major adverse cardiac events risk of hypertension and non-hypertensive patients was evaluated with Cox proportional hazards models. The prognostic associations between hypertension and no-hypertension with increasing degree of coronary stenosis severity (nonobstructive or obstructive ≥50%) and extent of coronary artery disease (segment involvement score of 1-5, >5) was also assessed. Hypertension patients less commonly had no coronary atherosclerosis and more commonly had nonobstructive and 1-, 2-, and 3-vessel disease than the no-hypertension group. During a mean follow-up of 5.2±1.2 years, 180 patients experienced cardiac events, with 104 (2.0%) occurring in the hypertension group and 76 (1.5%) occurring in the no-hypertension group (hazard ratios, 1.4; 95% confidence intervals, 1.0-1.9). Compared with no-hypertension patients without coronary atherosclerosis, hypertension patients with no coronary atherosclerosis and obstructive coronary disease tended to have higher risk of cardiac events. Similar trends were observed with respect to extent of coronary artery disease. Compared with no-hypertension patients, hypertensive patients have increased presence, extent, and severity of coronary atherosclerosis and tend to have an increase in major adverse cardiac events. © 2017 American Heart Association, Inc.

  12. Impact of Collateral Status Evaluated by Dynamic Computed Tomographic Angiography on Clinical Outcome in Patients With Ischemic Stroke

    NARCIS (Netherlands)

    van den Wijngaard, Ido R.; Boiten, Jelis; Holswilder, Ghislaine; Algra, Ale; Dippel, Diederik W J; Velthuis, Birgitta K.; Wermer, Marieke J H; van Walderveen, Marianne A A

    2015-01-01

    BACKGROUND AND PURPOSE—: Status of collateral circulation is a strong predictor of outcome after acute ischemic stroke. Our aim was to compare the predictive value of strategies for collateral blood flow assessment with dynamic computed tomographic angiography (CTA) and conventional single-phase CT

  13. Noncontrast computed tomographic Hounsfield unit evaluation of cerebral venous thrombosis: a quantitative evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Besachio, David A. [University of Utah, Department of Radiology, Salt Lake City (United States); United States Navy, Bethesda, MD (United States); Quigley, Edward P.; Shah, Lubdha M.; Salzman, Karen L. [University of Utah, Department of Radiology, Salt Lake City (United States)

    2013-08-15

    Our objective is to determine the utility of noncontrast Hounsfield unit values, Hounsfield unit values corrected for the patient's hematocrit, and venoarterial Hounsfield unit difference measurements in the identification of intracranial venous thrombosis on noncontrast head computed tomography. We retrospectively reviewed noncontrast head computed tomography exams performed in both normal patients and those with cerebral venous thrombosis, acquiring Hounsfield unit values in normal and thrombosed cerebral venous structures. Also, we acquired Hounsfield unit values in the internal carotid artery for comparison to thrombosed and nonthrombosed venous structures and compared the venous Hounsfield unit values to the patient's hematocrit. A significant difference is identified between Hounsfield unit values in thrombosed and nonthrombosed venous structures. Applying Hounsfield unit threshold values of greater than 65, a Hounsfield unit to hematocrit ratio of greater than 1.7, and venoarterial difference values greater than 15 alone and in combination, the majority of cases of venous thrombosis are identifiable on noncontrast head computed tomography. Absolute Hounsfield unit values, Hounsfield unit to hematocrit ratios, and venoarterial Hounsfield unit value differences are a useful adjunct in noncontrast head computed tomographic evaluation of cerebral venous thrombosis. (orig.)

  14. Noncontrast computed tomographic Hounsfield unit evaluation of cerebral venous thrombosis: a quantitative evaluation

    International Nuclear Information System (INIS)

    Besachio, David A.; Quigley, Edward P.; Shah, Lubdha M.; Salzman, Karen L.

    2013-01-01

    Our objective is to determine the utility of noncontrast Hounsfield unit values, Hounsfield unit values corrected for the patient's hematocrit, and venoarterial Hounsfield unit difference measurements in the identification of intracranial venous thrombosis on noncontrast head computed tomography. We retrospectively reviewed noncontrast head computed tomography exams performed in both normal patients and those with cerebral venous thrombosis, acquiring Hounsfield unit values in normal and thrombosed cerebral venous structures. Also, we acquired Hounsfield unit values in the internal carotid artery for comparison to thrombosed and nonthrombosed venous structures and compared the venous Hounsfield unit values to the patient's hematocrit. A significant difference is identified between Hounsfield unit values in thrombosed and nonthrombosed venous structures. Applying Hounsfield unit threshold values of greater than 65, a Hounsfield unit to hematocrit ratio of greater than 1.7, and venoarterial difference values greater than 15 alone and in combination, the majority of cases of venous thrombosis are identifiable on noncontrast head computed tomography. Absolute Hounsfield unit values, Hounsfield unit to hematocrit ratios, and venoarterial Hounsfield unit value differences are a useful adjunct in noncontrast head computed tomographic evaluation of cerebral venous thrombosis. (orig.)

  15. Statistical analysis of nonlinearly reconstructed near-infrared tomographic images: Part I--Theory and simulations.

    Science.gov (United States)

    Pogue, Brian W; Song, Xiaomei; Tosteson, Tor D; McBride, Troy O; Jiang, Shudong; Paulsen, Keith D

    2002-07-01

    Near-infrared (NIR) diffuse tomography is an emerging method for imaging the interior of tissues to quantify concentrations of hemoglobin and exogenous chromophores non-invasively in vivo. It often exploits an optical diffusion model-based image reconstruction algorithm to estimate spatial property values from measurements of the light flux at the surface of the tissue. In this study, mean-squared error (MSE) over the image is used to evaluate methods for regularizing the ill-posed inverse image reconstruction problem in NIR tomography. Estimates of image bias and image standard deviation were calculated based upon 100 repeated reconstructions of a test image with randomly distributed noise added to the light flux measurements. It was observed that the bias error dominates at high regularization parameter values while variance dominates as the algorithm is allowed to approach the optimal solution. This optimum does not necessarily correspond to the minimum projection error solution, but typically requires further iteration with a decreasing regularization parameter to reach the lowest image error. Increasing measurement noise causes a need to constrain the minimum regularization parameter to higher values in order to achieve a minimum in the overall image MSE.

  16. Computational diffraction tomographic microscopy with transport of intensity equation using a light-emitting diode array

    Science.gov (United States)

    Li, Jiaji; Chen, Qian; Zhang, Jialin; Zuo, Chao

    2017-10-01

    Optical diffraction tomography (ODT) is an effective label-free technique for quantitatively refractive index imaging, which enables long-term monitoring of the internal three-dimensional (3D) structures and molecular composition of biological cells with minimal perturbation. However, existing optical tomographic methods generally rely on interferometric configuration for phase measurement and sophisticated mechanical systems for sample rotation or beam scanning. Thereby, the measurement is suspect to phase error coming from the coherent speckle, environmental vibrations, and mechanical error during data acquisition process. To overcome these limitations, we present a new ODT technique based on non-interferometric phase retrieval and programmable illumination emitting from a light-emitting diode (LED) array. The experimental system is built based on a traditional bright field microscope, with the light source replaced by a programmable LED array, which provides angle-variable quasi-monochromatic illumination with an angular coverage of +/-37 degrees in both x and y directions (corresponding to an illumination numerical aperture of ˜ 0.6). Transport of intensity equation (TIE) is utilized to recover the phase at different illumination angles, and the refractive index distribution is reconstructed based on the ODT framework under first Rytov approximation. The missing-cone problem in ODT is addressed by using the iterative non-negative constraint algorithm, and the misalignment of the LED array is further numerically corrected to improve the accuracy of refractive index quantification. Experiments on polystyrene beads and thick biological specimens show that the proposed approach allows accurate refractive index reconstruction while greatly reduced the system complexity and environmental sensitivity compared to conventional interferometric ODT approaches.

  17. The use of transport and diffusion equations in the three-dimensional reconstruction of computerized tomographic images

    Energy Technology Data Exchange (ETDEWEB)

    Pires, Sandrerley Ramos, E-mail: sandrerley@eee.ufg.br [Escola de Engenharia Eletrica e de Computacao - EEEC, Universidade Federal de Goias - UFG, Goiania, GO (Brazil); Flores, Edna Lucia; Pires, Dulcineia Goncalves F.; Carrijo, Gilberto Arantes; Veiga, Antonio Claudio Paschoarelli [Faculdade de Engenharia Eletrica - FEELT, Universidade Federal de Uberlandia - UFU, Uberlandia, MG (Brazil); Barcelos, Celia Aparecida Z. [Faculdade de Matematica, Universidade Federal de Uberlandia - UFU, Uberlandia, MG (Brazil)

    2012-09-15

    The visualization of a computerized tomographic (TC) exam in 3D increases the quality of the medical diagnosis and, consequently, the success probability in the treatment. To obtain a high quality image it is necessary to obtain slices which are close to one another. Motivated towards the goal of reaching an improved balance between quantity of slices and visualization quality, this research work presents a digital inpainting technique of 3D interpolation for CT slices used in the visualization of human body structures. The inpainting is carried out via non-linear partial differential equations (PDE). The PDE's have been used, in the image-processing context to fill in the damaged regions in a digital 2D image. Inspired by this idea, this article proposes an interpolation method for the filling in of the empty regions between the CT slices. To do it, considering the high similarity between two consecutive real slice, the first step of the proposed method is to create the virtual slices. The virtual slices contain all similarity between the intercalated slices and, when there are not similarities between real slices, the virtual slices will contain indefinite portions. In the second step of the proposed method, the created virtual slices will be used together with the real slices images, in the reconstruction of the structure in three dimensions, mapped onto the exam. The proposed method is capable of reconstructing the curvatures of the patient's internal structures without using slices that are close to one another. The experiments carried out show the proposed method's efficiency. (author)

  18. Tomographic reconstruction of storm time RC ion distribution from ENA images on board multiple spacecraft

    Science.gov (United States)

    Ma, Shu-Ying; Yan, Wei-Nan; Xu, Liang

    2015-11-01

    A quantitative retrieval of 3-D distribution of energetic ions as energetic neutral atoms (ENA) sources is a challenging task. In this paper the voxel computerized tomography (CT) method is initially applied to reconstruct the 3-D distribution of energetic ions in the magnetospheric ring current (RC) region from ENA emission images on board multiple spacecraft. To weaken the influence of low-altitude emission (LAE) on the reconstruction, the LAE-associated ENA intensities are corrected by invoking the thick-target approximation. To overcome the divergence in iteration due to discordant instrument biases, a differential ENA voxel CT method is developed. The method is proved reliable and advantageous by numerical simulation for the case of constant bias independent of viewing angle. Then this method is implemented with ENA data measured by the Two Wide-angle Imaging Neutral-atom Spectrometers mission which performs stereoscopic ENA imaging. The 3-D spatial distributions and energy spectra of RC ion flux intensity are reconstructed for energies of 4-50 keV during the main phase of a major magnetic storm. The retrieved ion flux distributions seem to correspond to an asymmetric partial RC, located mainly around midnight favoring the postmidnight with L = 3.5-7.0 in the equatorial plane. The RC ion distributions with magnetic local time depend on energy, with major equatorial flux peak for lower energy located east of that for higher energy. In comparison with the ion energy spectra measured by Time History of Events and Macroscale Interactions during Substorms-D satellite flying in the RC region, the retrieved spectrum from remotely sensed ENA images are well matched with the in situ measurements.

  19. Development of tomographic reconstruction algorithms for the PIXE analysis of biological samples

    International Nuclear Information System (INIS)

    Nguyen, D.T.

    2008-05-01

    The development of 3-dimensional microscopy techniques offering a spatial resolution of 1 μm or less has opened a large field of investigation in Cell Biology. Amongst them, an interesting advantage of ion beam micro-tomography is its ability to give quantitative results in terms of local concentrations in a direct way, using Particle Induced X-ray Emission (PIXET) combined to Scanning Transmission Ion Microscopy (STIMT) Tomography. After a brief introduction of existing reconstruction techniques, we present the principle of the DISRA code, the most complete written so far, which is the basis of the present work. We have modified and extended the DISRA algorithm by considering the specific aspects of biologic specimens. Moreover, correction procedures were added in the code to reduce noise in the tomograms. For portability purpose, a Windows graphic interface was designed to easily enter and modify experimental parameters used in the reconstruction, and control the several steps of data reduction. Results of STIMT and PIXET experiments on reference specimens and on human cancer cells will be also presented. (author)

  20. Limited data tomographic image reconstruction via dual formulation of total variation minimization

    Science.gov (United States)

    Jang, Kwang Eun; Sung, Younghun; Lee, Kangeui; Lee, Jongha; Cho, Seungryong

    2011-03-01

    The X-ray mammography is the primary imaging modality for breast cancer screening. For the dense breast, however, the mammogram is usually difficult to read due to tissue overlap problem caused by the superposition of normal tissues. The digital breast tomosynthesis (DBT) that measures several low dose projections over a limited angle range may be an alternative modality for breast imaging, since it allows the visualization of the cross-sectional information of breast. The DBT, however, may suffer from the aliasing artifact and the severe noise corruption. To overcome these problems, a total variation (TV) regularized statistical reconstruction algorithm is presented. Inspired by the dual formulation of TV minimization in denoising and deblurring problems, we derived a gradient-type algorithm based on statistical model of X-ray tomography. The objective function is comprised of a data fidelity term derived from the statistical model and a TV regularization term. The gradient of the objective function can be easily calculated using simple operations in terms of auxiliary variables. After a descending step, the data fidelity term is renewed in each iteration. Since the proposed algorithm can be implemented without sophisticated operations such as matrix inverse, it provides an efficient way to include the TV regularization in the statistical reconstruction method, which results in a fast and robust estimation for low dose projections over the limited angle range. Initial tests with an experimental DBT system confirmed our finding.

  1. Analysis of computed tomographic manifestations of primary lung cancer by histologic types

    International Nuclear Information System (INIS)

    Kim, Kyo Yeoun; Choe, Kyu Ok

    1988-01-01

    It is well known that primary lung cancer is one of the most common malignancies in Korea. With respect to the histologic type, primary lung carcinoma manifests itself in a number of different ways. The authors analyzed the computed tomographic (C-T) findings of 183 cases of pathologically confirmed primary lung cancer from 1983 to Aug. 1987 without prior information of histologic types. The results are as follows. 1. The distribution of histologic types of primary lung cancer was as follows: epidermoid carcinoma, 96 cases (52.5%); adenocarcinoma, 43 cases (23.5%); undifferentiated large cell carcinoma, 17 cases (9.2%) and undifferentiated small cell carcinoma, 27 cases (14.8%). 2. The male to female ratio was 3.9:1, the highest ratio occurring in undifferentiated small cell carcinoma 12.5:1 and the lowest ratio in adenocarcinoma 1.1:1 where there was no significant difference in the male to female ratio. 3. Chest computed tomographic findings by histologic type were as follows: (a) Epidermoid carcinoma (96 cases): The central type was the most prevalent (52 cases) with an incidence of 54%. Major air way obstruction was most frequently encountered in this type and was complete in 60% of the cases and partial in 25%. The incidence of cavitating malignancy was 10%, more common than other histologica types. (b) Adenocarcinoma (43 cases): The peripheral type was the most prevalent (28 cases) with an incidence of 63%. Lung to lung metastasis was 23%, more common than other histologic types. (c) Undifferentiated large cell carcinoma (17 cases): The highest incidence occurred in the peripheral type, 9 cases (53%). Chest wall involvement was 12%, more common than other histologic types. (d) Undifferentiated small cell carcinoma (27 cases): The central type (19 cases) presented the highest incidence (70%). Major air way obstruction was noted less severe than epidermoid carcinoma: complete 33%, partial 63%. The incidence of pericardial effusion and/or thickening was 18

  2. Distributed MRI reconstruction using Gadgetron-based cloud computing.

    Science.gov (United States)

    Xue, Hui; Inati, Souheil; Sørensen, Thomas Sangild; Kellman, Peter; Hansen, Michael S

    2015-03-01

    To expand the open source Gadgetron reconstruction framework to support distributed computing and to demonstrate that a multinode version of the Gadgetron can be used to provide nonlinear reconstruction with clinically acceptable latency. The Gadgetron framework was extended with new software components that enable an arbitrary number of Gadgetron instances to collaborate on a reconstruction task. This cloud-enabled version of the Gadgetron was deployed on three different distributed computing platforms ranging from a heterogeneous collection of commodity computers to the commercial Amazon Elastic Compute Cloud. The Gadgetron cloud was used to provide nonlinear, compressed sensing reconstruction on a clinical scanner with low reconstruction latency (eg, cardiac and neuroimaging applications). The proposed setup was able to handle acquisition and 11 -SPIRiT reconstruction of nine high temporal resolution real-time, cardiac short axis cine acquisitions, covering the ventricles for functional evaluation, in under 1 min. A three-dimensional high-resolution brain acquisition with 1 mm(3) isotropic pixel size was acquired and reconstructed with nonlinear reconstruction in less than 5 min. A distributed computing enabled Gadgetron provides a scalable way to improve reconstruction performance using commodity cluster computing. Nonlinear, compressed sensing reconstruction can be deployed clinically with low image reconstruction latency. © 2014 Wiley Periodicals, Inc.

  3. The CDD system in computed tomographic diagnosis of diverticular disease; Das CDD-System in der computertomografischen Diagnostik der Divertikelkrankheit

    Energy Technology Data Exchange (ETDEWEB)

    Pustelnik, Daniel; Elsholtz, Fabian Henry Juergen; Hamm, Bernd; Niehues, Stefan Markus [Charite - Universitaetsmedizin, Berlin (Germany). Inst. of Radiology; Bojarski, Christian [Charite - Universitaetsmedizin, Berlin (Germany). Div. of Gastroenterology, Infectiology and Rheumatology

    2017-08-15

    Purpose cation in computed tomographic diagnosis and briefly recapitulates its targeted advantages over preliminary systems. Primarily, application of the CDD in computed tomography diagnostics is described. Differences with respect to the categories of the older systems are pointed out on the level of each CDD type using imaging examples. The presented images are derived from our institute according to the S2k criteria. Literature was researched on PubMed. Results The CDD constitutes an improvement compared to older systems for categorizing the stages of diverticular disease. It provides more discriminatory power on the descriptive-morphological level and defines as well as differentiates more courses of the disease. Furthermore, the categories translate more directly into state-of-the-art decision-making concerning hospitalization and therapy. The CDD should be applied routinely in the computed tomographic diagnosis of diverticular disease. Typical imaging patterns are presented.

  4. Clinical perspective of coronary computed tomographic angiography in diagnosis of coronary artery disease

    International Nuclear Information System (INIS)

    Chang, Hyuk-Jae; Chung, Namsik

    2011-01-01

    Since a 4-detector row coronary computed tomographic angiography (CCTA) was launched in 1998, CCTA has experienced rapid improvement of imaging qualities with the ongoing evolution of computed tomography (CT) technology. The diagnostic accuracy of CCTA to detect coronary artery stenosis is well established, whereas improvements are still needed to reduce the overestimation of coronary artery disease (CAD) and assess plaque composition. CCTA has been used to evaluate CAD in various clinical settings. For example, CCTA could be an efficient initial triage tool at emergency departments for patients with acute chest pain with low-to-intermediate risk because of its high negative predictive value. In patients with suspected CAD, CCTA could be a cost-effective alternative to myocardial perfusion imaging and exercise electrocardiogram for the initial coronary evaluation of patients with intermediate pre-test likelihood suspected CAD. However, in asymptomatic populations, there is a lack of studies that show an improved prognostic power of CCTA over other modalities. Therefore, the clinical use of CCTA to detect CAD for purposes of risk stratification in asymptomatic individuals should be discouraged. As CT technology evolves, CCTA will provide better quality coronary imaging and non-coronary information with lower radiation exposure. Future studies should cover these ongoing technical improvements and evaluate the prognostic power of CCTA in various clinical settings of CAD in large, well-designed, randomized trials. (author)

  5. [X-ray computed tomographic aspects of benign primary cerebral melanomas. Apropos of 4 cases].

    Science.gov (United States)

    Adam, P; Alberge, Y; Espagno, C; Bouzigues, J Y

    1986-02-01

    Benign primitive melanomas are rare tumours usually involving the leptomeninges. Four cranial localizations are reported: 2 tumours of the foramen magnum, 1 of the cerebellopontine angle and 1 supratentorial. The clinical symptomatology is variable according to the level. Slow medullary compression is frequent. One can emphasize the special and difficult problem of foramen magnum tumours that present with a very variable clinical status frequently simulating a non surgical disease of the central nervous system. The benign and primitive appearance of these tumours is evocated by the slow and favourable evolution and by the absence of extraneurologic melanotic tumour. Our purpose is essentially to emphasize the radiological and particularly the computed tomographic (CT) findings poorly described in the literature. Benign melanomas have resemblance with meningiomas: osseous or meningeal relationship, homogeneity and high density. On the other hand the angiography shows poor vascularization. One can think that a tumor simulating a meningioma by CT but not by angiography is perhaps a benign melanoma. The special problem of the radiological diagnosis of foramen magnum tumours is evocated: Computed myelography, tridimensional imaging by NMR.

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

    Science.gov (United States)

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

    2012-05-01

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

  7. Computed tomographic characteristics of collateral venous pathways in dogs with caudal vena cava obstruction.

    Science.gov (United States)

    Specchi, Swan; d'Anjou, Marc-André; Carmel, Eric Norman; Bertolini, Giovanna

    2014-01-01

    Collateral venous pathways develop in dogs with obstruction or increased blood flow resistance at any level of the caudal vena cava in order to maintain venous drainage to the right atrium. The purpose of this retrospective study was to describe the sites, causes of obstruction, and configurations of venous collateral pathways for a group of dogs with caudal vena cava obstruction. Computed tomography databases from two veterinary hospitals were searched for dogs with a diagnosis of caudal vena cava obstruction and multidetector row computed tomographic angiographic (CTA) scans that included the entire caudal vena cava. Images for each included dog were retrieved and collateral venous pathways were characterized using image postprocessing and a classification system previously reported for humans. A total of nine dogs met inclusion criteria and four major collateral venous pathways were identified: deep (n = 2), portal (n = 2), intermediate (n = 7), and superficial (n = 5). More than one collateral venous pathway was present in 5 dogs. An alternative pathway consisting of renal subcapsular collateral veins, arising mainly from the caudal pole of both kidneys, was found in three dogs. In conclusion, findings indicated that collateral venous pathway patterns similar to those described in humans are also present in dogs with caudal vena cava obstruction. These collateral pathways need to be distinguished from other vascular anomalies in dogs. Postprocessing of multidetector-row CTA images allowed delineation of the course of these complicated venous pathways and may be a helpful adjunct for treatment planning in future cases. © 2014 American College of Veterinary Radiology.

  8. Three-dimensional computed tomographic volumetry precisely predicts the postoperative pulmonary function.

    Science.gov (United States)

    Kobayashi, Keisuke; Saeki, Yusuke; Kitazawa, Shinsuke; Kobayashi, Naohiro; Kikuchi, Shinji; Goto, Yukinobu; Sakai, Mitsuaki; Sato, Yukio

    2017-11-01

    It is important to accurately predict the patient's postoperative pulmonary function. The aim of this study was to compare the accuracy of predictions of the postoperative residual pulmonary function obtained with three-dimensional computed tomographic (3D-CT) volumetry with that of predictions obtained with the conventional segment-counting method. Fifty-three patients scheduled to undergo lung cancer resection, pulmonary function tests, and computed tomography were enrolled in this study. The postoperative residual pulmonary function was predicted based on the segment-counting and 3D-CT volumetry methods. The predicted postoperative values were compared with the results of postoperative pulmonary function tests. Regarding the linear correlation coefficients between the predicted postoperative values and the measured values, those obtained using the 3D-CT volumetry method tended to be higher than those acquired using the segment-counting method. In addition, the variations between the predicted and measured values were smaller with the 3D-CT volumetry method than with the segment-counting method. These results were more obvious in COPD patients than in non-COPD patients. Our findings suggested that the 3D-CT volumetry was able to predict the residual pulmonary function more accurately than the segment-counting method, especially in patients with COPD. This method might lead to the selection of appropriate candidates for surgery among patients with a marginal pulmonary function.

  9. Development of a tomographic system adapted to 3D measurement of contaminated wounds based on the Cacao concept (Computer aided collimation Gamma Camera)

    International Nuclear Information System (INIS)

    Douiri, A.

    2002-03-01

    The computer aided collimation gamma camera (CACAO in French) is a gamma camera using a collimator with large holes, a supplementary linear scanning motion during the acquisition and a dedicated reconstruction program taking full account of the source depth. The CACAO system was introduced to improve both the sensitivity and the resolution in nuclear medicine. This thesis focuses on the design of a fast and robust reconstruction algorithm in the CACAO project. We start by an overview of tomographic imaging techniques in nuclear medicine. After modelling the physical CACAO system, we present the complete reconstruction program which involves three steps: 1) shift and sum 2) deconvolution and filtering 3) rotation and sum. The deconvolution is the critical step that decreases the signal to noise ratio of the reconstructed images. We propose a regularized multi-channel algorithm to solve the deconvolution problem. We also present a fast algorithm based on Splines functions and preserving the high quality of the reconstructed images for the shift and the rotation steps. Comparisons of simulated reconstructed images in 2D and 3D for the conventional system (CPHC) and CACAO demonstrate the ability of CACAO system to increase the quality of the SPECT images. Finally, this study concludes with an experimental approach with a pixellated detector conceived for a 3D measurement of contaminated wounds. This experimentation proves the possible advantages of coupling the CACAO project with pixellated detectors. Moreover, a variety of applications could fully benefit from the CACAO system, such as low activity imaging, the use of high-energy gamma isotopes and the visualization of deep organs. Moreover the combination of the CACAO system with a pixels detector may open up further possibilities for the future of nuclear medicine. (author)

  10. BPF-type region-of-interest reconstruction for parallel translational computed tomography.

    Science.gov (United States)

    Wu, Weiwen; Yu, Hengyong; Wang, Shaoyu; Liu, Fenglin

    2017-01-01

    The objective of this study is to present and test a new ultra-low-cost linear scan based tomography architecture. Similar to linear tomosynthesis, the source and detector are translated in opposite directions and the data acquisition system targets on a region-of-interest (ROI) to acquire data for image reconstruction. This kind of tomographic architecture was named parallel translational computed tomography (PTCT). In previous studies, filtered backprojection (FBP)-type algorithms were developed to reconstruct images from PTCT. However, the reconstructed ROI images from truncated projections have severe truncation artefact. In order to overcome this limitation, we in this study proposed two backprojection filtering (BPF)-type algorithms named MP-BPF and MZ-BPF to reconstruct ROI images from truncated PTCT data. A weight function is constructed to deal with data redundancy for multi-linear translations modes. Extensive numerical simulations are performed to evaluate the proposed MP-BPF and MZ-BPF algorithms for PTCT in fan-beam geometry. Qualitative and quantitative results demonstrate that the proposed BPF-type algorithms cannot only more accurately reconstruct ROI images from truncated projections but also generate high-quality images for the entire image support in some circumstances.

  11. Cophylogeny reconstruction via an approximate Bayesian computation.

    Science.gov (United States)

    Baudet, C; Donati, B; Sinaimeri, B; Crescenzi, P; Gautier, C; Matias, C; Sagot, M-F

    2015-05-01

    Despite an increasingly vast literature on cophylogenetic reconstructions for studying host-parasite associations, understanding the common evolutionary history of such systems remains a problem that is far from being solved. Most algorithms for host-parasite reconciliation use an event-based model, where the events include in general (a subset of) cospeciation, duplication, loss, and host switch. All known parsimonious event-based methods then assign a cost to each type of event in order to find a reconstruction of minimum cost. The main problem with this approach is that the cost of the events strongly influences the reconciliation obtained. Some earlier approaches attempt to avoid this problem by finding a Pareto set of solutions and hence by considering event costs under some minimization constraints. To deal with this problem, we developed an algorithm, called Coala, for estimating the frequency of the events based on an approximate Bayesian computation approach. The benefits of this method are 2-fold: (i) it provides more confidence in the set of costs to be used in a reconciliation, and (ii) it allows estimation of the frequency of the events in cases where the data set consists of trees with a large number of taxa. We evaluate our method on simulated and on biological data sets. We show that in both cases, for the same pair of host and parasite trees, different sets of frequencies for the events lead to equally probable solutions. Moreover, often these solutions differ greatly in terms of the number of inferred events. It appears crucial to take this into account before attempting any further biological interpretation of such reconciliations. More generally, we also show that the set of frequencies can vary widely depending on the input host and parasite trees. Indiscriminately applying a standard vector of costs may thus not be a good strategy. © The Author(s) 2014. Published by Oxford University Press, on behalf of the Society of Systematic Biologists.

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

    Science.gov (United States)

    Gao, Fei; Wang, Guo-Bao; Xiang, Zhan-Wang; Yang, Bin; Xue, Jing-Bing; Mo, Zhi-Qiang; Zhong, Zhi-Hui; Zhang, Tao; Zhang, Fu-Jun; Fan, Wei-Jun

    2016-05-03

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

  13. Correlation between presumed sinusitis-induced pain and paranasal sinus computed tomographic findings.

    Science.gov (United States)

    Mudgil, Shikha P; Wise, Scott W; Hopper, Kenneth D; Kasales, Claudia J; Mauger, David; Fornadley, John A

    2002-02-01

    The correlation between facial and/or head pain in patients clinically suspected of having sinusitis and actual localized findings on sinus computed tomographic (CT) imaging are poorly understood. To prospectively evaluate the relationship of paranasal sinus pain symptoms with CT imaging. Two hundred consecutive patients referred by otolaryngologists and internists for CT of the paranasal sinuses participated by completing a questionnaire immediately before undergoing CT. Three radiologists blinded to the patients' responses scored the degree of air/fluid level, mucosal thickening, bony reaction, and mucus retention cysts using a graded scale of severity (0 to 3 points). The osteomeatal complexes and nasolacrimal ducts were also evaluated for patency. Bivariate analysis was performed to evaluate the relationship between patients' localized symptoms and CT findings in the respective sinus. One hundred sixty-three patients (82%) reported having some form of facial pain or headache. The right temple/forehead was the most frequently reported region of maximal pain. On CT imaging the maxillary sinus was the most frequently involved sinus. Bivariate analysis failed to show any relationship between patient symptoms and findings on CT. Patients with a normal CT reported a mean 5.88 sites of facial or head pain versus 5.45 sites for patients with an abnormal CT. Patient-based responses of sinonasal pain symptoms fail to correlate with findings in the respective sinuses. CT should therefore be reserved for delineating the anatomy and degree of sinus disease before surgical intervention.

  14. Computed tomographic analysis of vegetable during far infrared radiation drying process

    International Nuclear Information System (INIS)

    Maneechot, P.; Tojo, S.; Watanabe, K.

    2006-01-01

    Far Infrared Radiation (FIR) technology is widely used in the automotive industry to cure painted finishes during manufacturing. FIR drying is used not only in manufacturing but also in agricultural processing such as rice drying. At the present time, FIR drying technology has rarely been used for fruits and vegetables except in research laboratories. In this study, FIR drying and hot air convection drying were compared with respect to energy consumption and time requirement. The internal changes of the agricultural product were also observed during the FIR drying process. A Computed Tomographic (CT) scanner was employed for the observation of the tested material, carrot, and was used to analyze the structural deformation and the internal moisture distribution of the test material. CT data and the hardness of the sample were recorded at regular intervals during the drying experiment. For 200, 400 and 600W FIR drying, the maximum drying rates were 173, 459 and 724%d.b./hr respectively, and the required drying times were 26, 12 and 4.5 hours, respectively. The structure of the carrot sample shrank in accordance with the reduction of moisture content in 200W FIR drying as well as in hot air drying, whereas in 400W and 600W FIR drying the sample was dried without so much deformation

  15. Diagnostic performance of 64-slice multidetector coronary computed tomographic angiography in women.

    Science.gov (United States)

    Jug, Borut; Gupta, Mohit; Papazian, Jenny; Li, Dong; Tsang, Janet; Bhatia, Harpreet; Karlsberg, Ronald; Budoff, Matthew

    2012-12-01

    Diagnostic approach to chest pain in women is challenging, but still under-investigated. The purpose of this study was to assess the diagnostic performance of 64-slice multidetector coronary computed tomographic angiography (CCTA) in women with chest pain. We included 606 patients--255 women and 351 men (mean age 61 ± 12 years for both)--who had been referred for a CCTA and an invasive coronary angiography (diagnostic standard) because of chest pain, either as part of clinical work-up in two urban medical centers or as part of the multicenter ACCURACY trial. On a patient-based model, the sensitivity, specificity, and positive predictive value (PPV) and negative predictive value to detect ≥50% and ≥70% stenosis were 98%, 84%, 87%, and 97% and 96%, 83%, 77%, and 97%, respectively, for women and 97%, 83%, 89%, and 95% and 94%, 91%, 90%, and 94%, respectively, for men. There were no statistically significant differences between men and women in diagnostic performance measures except for the PPV of detecting a ≥70% stenosis (P = .007). In women with chest pain, 64-slice multidetector CCTA is at least as sensitive and specific as in men. Our findings suggest that CCTA is a promising diagnostic tool for timely detection and/or exclusion of CAD in symptomatic intermediate-risk female populations.

  16. Computed tomographic colonography (CTC); colorectal cancer diagnosis with CTC in an Auckland population

    International Nuclear Information System (INIS)

    Moore, Helen; Dodd, Nicholas

    2013-01-01

    To determine the sensitivity of computed tomographic colonography (CTC) in the detection of colorectal cancer in our population and evaluate the reasons why these lesions may be missed on CTC. All patients who underwent CTC in the 65-month period from 1 January 2004 to 1 July 2009 were included in the analysis. Demographic data and CTC findings were recorded, according to the CT Colonography Reporting and Data System. Data were cross-matched with the National Cancer Registry results for colorectal cancer cases between 1 January 2004 and 1 October 2009, 3 months longer to include any delayed diagnoses. There were 2026 consecutive CTC patients, comprising 52.6% female, average age of 60 years; range 19–87. Approximately 84% were symptomatic. There were 45 confirmed colorectal cancers among this patient group in the National Cancer Registry during the relevant time period compared with 43 suspected cancers on CTC, giving a miss rate of 2 of 45, or 4.4%. The sensitivity of 95% for CTC in the detection of colorectal cancer compares favourably with the published national and international data.

  17. Computed Tomographic Findings and Mortality in Patients With Pneumomediastinum From Blunt Trauma.

    Science.gov (United States)

    Lee, Wayne S; Chong, Vincent E; Victorino, Gregory P

    2015-08-01

    The care of most patients with pneumomediastinum (PNM) due to trauma can be managed conservatively; however, owing to aerodigestive tract injury and other associated injuries, there is a subset of patients with PNM who are at higher risk of mortality but can be difficult to identify. To characterize computed tomographic (CT) findings associated with mortality in patients with PNM due to blunt trauma. A retrospective review of medical records from January 1, 2002, to December 31, 2011, was conducted at a university-based urban trauma center. The patients evaluated were those injured by blunt trauma and found to have PNM on initial chest CT scanning. Data analysis was performed July 2, 2013, to June 18, 2014. In-hospital mortality. During the study period, 3327 patients with blunt trauma underwent chest CT. Of these, 72 patients (2.2%) had PNM. Patients with PNM had higher Injury Severity Scores (P blunt trauma; however, CT findings of posterior PNM, air in all mediastinal compartments, and concurrent hemothorax are associated with increased mortality. These CT findings could be used as a triage tool to alert the trauma surgeon to a potentially lethal injury.

  18. Accuracy of computed tomographic intravenous cholangiography (CT-IVC) with iotroxate in the detection of choledocholithiasis

    International Nuclear Information System (INIS)

    Gibson, Robert N.; Vincent, Janette M.; Speer, Tony; Noack, Keith; Collier, Neil A.

    2005-01-01

    To determine the accuracy of computed tomographic intravenous cholangiography (CT-IVC) for detection of choledocholithiasis. Sixty-five patients undergoing endoscopic retrograde cholangiography (ERC) underwent CT-IVC prior to ERC, using a single detector helical CT following intravenous infusion of 100 ml iotroxate. Patients with bilirubin levels >3 times normal were excluded. ERC was indeterminate in three patients (4.7%) and CT-IVC in four (6.3%). Twenty-three patients had ductal calculi at ERC, and CT-IVC was positive in 22, with two false positives and one false negative: sensitivity 95.6%, specificity 94.3%. Stones were multiple in nine and solitary in 14. Of the 14 solitary stones, ten were ≤5 mm and eight were ≤4 mm. The bilirubin level in positive cases was within normal in 20. Maximum intensity projection (MIP) reformats showed stones in only 27% of cases and surface rendered (SR) reformats in none. CT-IVC is highly accurate for detection of ductal calculi, including single small calculi, with a normal or near normal serum bilirubin. Axial images should be used for interpretation rather than MIP or SR reformats. (orig.)

  19. [Computed tomographic semiotics of respiratory tuberculosis in HIV-infected patients].

    Science.gov (United States)

    Gavrilov, P V; Lazareva, A S; Malashenkov, E A

    2013-01-01

    to study the computed tomographic (CT) semiotics of respiratory tuberculosis in HIV-infected patients in relation to the degree of immunosuppression. The study enrolled 74 patients with verified respiratory tuberculosis in the presence of HIV infection. According to the degree of immunosuppression and the Centers for Disease Control (CDC) and Prevention classification (Atlanta, USA, 1993), the patients were divided into 3 groups: (1) CD4 > or = 500 cells/microl (n = 10); 2) CD4 200-499 cells/microl (n = 28); (3) CD4 <200 cells/microl (n = 36). With spiral CT, focal changes with a predominance of clear-cut foci are visualized at a high frequency in the patients with pulmonary tuberculosis in the presence of HIV infection. In progressive immunosuppression, the CT pattern displays atypical syndromes (frosted glass-type foci, interstitial infiltration, and thin-walled cavities) with the lower rate of alveolar infiltration with confluent foci, as well as lung tissue decay. Enlarged intrathoracic lymph nodes are characteristic of 70.0% of the patients with HIV infection and tuberculosis regardless of the level of CD4 cells. As immunosuppression progresses, the CT pattern of respiratory tuberculosis in the presence of HIV infection shows as atypical syndromes (unclearly defined frosted glass-type focal changes, interstitial infiltrations, and thin-walled cavernous masses). A marked polymorphism in changes and a high rate of lymph node involvement are characteristic.

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

    International Nuclear Information System (INIS)

    Takahashi, Ryosuke; Imai, Terukuni; Sadashima, Hiromichi; Matsumoto, Sadayuki; Yamamoto, Toru; Kusaka, Hirobumi; Yamasaki, Masahiro; Maya, Kiyomi; Tanabe, Masaya

    1989-01-01

    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)

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

    International Nuclear Information System (INIS)

    Yu Hui; Higa, Futoshi; Hibiya, Kenji; Furugen, Makoto; Sato, Yoko; Shinzato, Takashi; Haranaga, Shusaku; Yara, Satomi; Tateyama, Masao; Fujita, Jiro; Li, Huiping

    2010-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. X-rays computed tomographic scans of lower limb and trunk muscles in facioscapulohumeral muscular dystrophy

    Energy Technology Data Exchange (ETDEWEB)

    Horikawa, Hirosei; Mano, Yukio; Takayanagi, Tetsuya [Nara Medical Univ., Kashihara (Japan); Takahashi, Keiichi; Nishio, Hisahide

    1992-10-01

    X-rays computed tomographic (CT) scans of muscles of the lower limbs and the trunk in 14 patients with facioscapulohumeral muscular dystrophy (FSH) were studied. The CT scans showed that the affected muscles were decreased in density and size. The laterality of muscular involvement was sometimes observed. The muscular lesions in the lower limbs showed proximal distribution. In the thigh, the hamstrings were affected first, the adductor muscles second, and then the muscular involvement progressed to the quadriceps femoris muscle. In the lower leg, the gastrocnemius and soleus muscles were relatively spared as compared with the tibialis anterior muscle. In the lumbar girdle, the abdominal muscles were involved first, the gluteal muscles second, the back muscles third, and the psoas major muscle were relatively spared. The muscular weakness of this distribution exacerbated lumbar lordosis. The neck muscles were less affected than those of the lumbar girdle. The CT scans in FSH demonstrated the characteristic pattern of muscular involvement, which differed from the inherited muscular diseases such as Duchenne muscular dystrophy, myotonic dystrophy, and others. (author).

  4. X-rays computed tomographic scans of lower limb and trunk muscles in facioscapulohumeral muscular dystrophy

    International Nuclear Information System (INIS)

    Horikawa, Hirosei; Mano, Yukio; Takayanagi, Tetsuya; Takahashi, Keiichi; Nishio, Hisahide.

    1992-01-01

    X-rays computed tomographic (CT) scans of muscles of the lower limbs and the trunk in 14 patients with facioscapulohumeral muscular dystrophy (FSH) were studied. The CT scans showed that the affected muscles were decreased in density and size. The laterality of muscular involvement was sometimes observed. The muscular lesions in the lower limbs showed proximal distribution. In the thigh, the hamstrings were affected first, the adductor muscles second, and then the muscular involvement progressed to the quadriceps femoris muscle. In the lower leg, the gastrocnemius and soleus muscles were relatively spared as compared with the tibialis anterior muscle. In the lumbar girdle, the abdominal muscles were involved first, the gluteal muscles second, the back muscles third, and the psoas major muscle were relatively spared. The muscular weakness of this distribution exacerbated lumbar lordosis. The neck muscles were less affected than those of the lumbar girdle. The CT scans in FSH demonstrated the characteristic pattern of muscular involvement, which differed from the inherited muscular diseases such as Duchenne muscular dystrophy, myotonic dystrophy, and others. (author)

  5. Multislice coronary computed tomographic angiography in emergency department presentations of unsuspected acute myocardial infarction.

    Science.gov (United States)

    Hecht, Harvey S; Bhatti, Tandeep

    2009-01-01

    Coronary computed tomographic angiography (CCTA) is not indicated in the setting of acute myocardial infarction in the emergency department (ED). Nonetheless, acute coronary syndromes may have atypical presentations, and CCTA may be inadvertently performed in this setting. This study was designed to determine the frequency and characteristics of CCTA imaging of unsuspected acute myocardial infarction in the ED. All CCTAs performed in the ED at Lenox Hill Hospital were reviewed for clinical indications and subsequent course; patients with documented acute myocardial infarction were identified. Of the 500 CCTAs performed on ED patients in the Lenox Hill laboratory, 5 patients (1%) were imaged during the initial phase of an unsuspected acute myocardial infarction; in all cases the CCTAs were key to the diagnosis. The imaging characteristics were (1) total or subtotal occlusion and (2) transmural hypodensity in the infarct area. Although acute myocardial infarction on CCTA in ED patients is an infrequent event, proper and prompt recognition is critical for appropriate patient care, particularly as applications to the ED increase.

  6. Comparison of primary thyroid lymphoma with anaplastic thyroid carcinoma on computed tomographic imaging

    International Nuclear Information System (INIS)

    Ishikawa, Hitoshi; Mitsuhashi, Norio; Niibe, Hideo

    2002-01-01

    Primary non-Hodgkin's lymphoma (LY) and anaplastic carcinoma (AC) of the thyroid gland are rare malignant tumors, and the initial symptoms of these diseases are very similar. The aim of our study was to compare the characteristics of the two diseases using computed tomographic (CT) scans in order to make an accurate differential diagnosis. Ten patients with LY and 10 with AC were analyzed. Differences in the CT findings of the two diseases were evaluated before treatment and statistically tested with either Student's t-test or the chi-square test. In the analysis of characteristics of CT imaging, the existence of calcification and necrosis, and heterogeneous tumor were dominant findings in AC, and there was a statistically significant difference in frequency between the two diseases (p<0.01). Calcification detected in AC was usually multiple and/or gross (mean size: φ8.2 mm). All lymphadenopathies were delineated as having the same homogeneous attenuation as the tumors in the thyroid gland in LY, but were shown as irregular rim enhancement in AC. The CT features of the two diseases are characteristic in terms of calcification, necrosis, and tumor composition. Evaluation by means of CT imaging is useful in distinguishing between LY and AC. (author)

  7. Gastrointestinal stromal tumors: retrospective analysis of the computer-tomographic aspects.

    Science.gov (United States)

    Lupescu, Ioana G; Grasu, Mugur; Boros, Mirela; Gheorghe, Cristian; Ionescu, Mihnea; Popescu, Irinel; Herlea, Vlad; Georgescu, Serban A

    2007-06-01

    To describe the computer-tomographic (CT) aspects of gastrointestinal stromal tumors (GISTs) in correlation to their histology. The medical records of all patients at our hospital with a histologic diagnosis of GIST between January 2002 and June 2006, and investigated before surgery by CT, were reviewed. Two radiologists with knowledge of the diagnosis reviewed the CT findings. Amongst 15 cases of GISTs, 9 cases involved the stomach and 4 cases the small intestine. Location of the primary tumor could not be determined for 2 of 15 tumors, because of the presence of extensive peritoneal metastases. Most primary tumors were predominantly extraluminal (13 cases) while two were clearly endoluminal. The mean diameter of the primary tumor was 8 cm. The tumor margin was well defined in 12 patients and irregular in 3 cases. Central fluid attenuation was present in 11 tumors, while central gas was seen in two cases. Metastases were seen in 2 cases at presentation and in another 2 patients during follow-up. Spread was exclusive to the liver or peritoneum. Visceral obstruction was absent even in extensive peritoneal metastatic disease. Ascites was an unusual finding. CT plays an important role not only in the detection and the localization but also in the evaluation of the extension and follow-up of theses tumors. Using only CT aspects, we can only suspect the diagnosis to GISTs. Often other soft-tissue tumors with gastrointestinal involvement can mimic GISTs. In all cases histological diagnosis is essential.

  8. Evaluation of computed tomographic and radiographic myelography in normal miniature pigs

    International Nuclear Information System (INIS)

    Choi, M.H.; Lee, H.Y.; Kim, M.E.; Kim, J.Y.; Lee, N.S.; Chang, J.H.; Jung, J.H.; Choi, M.C.

    2010-01-01

    Evaluation of the myelography was studied in miniature pigs. Radiographs and computed tomographic (CT) images of the whole spine were obtained at clinically healthy twelve miniature pigs of 4 (8.7-10 kg) and 12 (26-31 kg) months. The assessments of the spinal cord were made in accordance with the Pavlov's method and compared area ratio [at spinal cord (SC), vertebral canal (VC) and vertebral body (VB)]. The Pavlov's ratio in the cervical spine was significant larger than that of thoracolumbar in radiographic myelography. On CT myelography, the area of the spinal cord had a significant difference between the cervical and thoracolumbar spine. Among the cervical spine, the ratios of spinal cord and vertebral body (SC : VB), vertebral canal and vertebral body (VC : VB) were minimum at the level of 4th cervical spine in both ages, while maximum at the level of 6th cervical spine in both months. In case of lumbar spine, the ratios of spinal cord and vertebral body (SC : VB) were the largest at the level of 4th lumbar spine in 4 months and at the level of 3rd lumbar spine in 12 months. In addition, the ratio of spinal cord and vertebral body (SC : VB) of the cervical spinal cord was significant lower at 4 months but the lumbar spinal cord showed lower pattern at 12 months old miniature pigs

  9. Morphologic analysis of Japanese adult sacroiliac joint using computed tomographic images

    International Nuclear Information System (INIS)

    Pan, Xuanchao; Takayama, Akinori; Shibata, Yasuaki; Ito, Hiromoto

    2003-01-01

    The purpose of this study was to study the relationship of angles in adult sacroiliac joints (SJ) with laterality, age, gender, degeneration, childbearing in different locations. The study was performed in 92 healthy Japanese adult volunteers (46 males and 46 females, aged 21∼86 years) who had no low back complaints. Axial computed tomographic (CT) images were obtained using an X-VIGOR apparatus (Toshiba Medical Inc. Japan). The angle measurements were taken directly using soft National Institutes of Health (NIH) Image 1.61 (Scion Inc. USA). We examined possible factors. Statistical evaluation was calculated using t-test by soft SPSS (SPSS Inc. Japan). Our findings indicated that SJ angles had no relationships with laterality, gender. But from upper part to lower part, the average of SJ angle was 7.61 deg±8.7 deg, 5.16 deg±7.3 deg, -0.85 deg±7.3 deg respectively in the left and 6.56 deg±9.4 deg, 4.10 deg±7.2 deg, -2.30 deg±7.0 deg in the right. The difference is significant between lower part and upper-middle part (P<0.05). Our results provided new anatomic and morphological data for better understandings of SJ in the clinic work. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    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).

  11. Results of computer-tomographic examination in different forms and course of schizophrenia

    International Nuclear Information System (INIS)

    Stojchev, R.

    1991-01-01

    Data are reported of a clinical and computer-tomographic study of 103 schizophrenic patients. Those with simple form of the disease had most pronounced evidence of dilated III and lateral ventricles (41.8% of the cases for the III ventricle and 72.4% for the lateral ventricles). All patients with circular, simple and catatonic form had signs of pathology of the cortical sulci. Regarding the ventricular system evidences of pathology prevailed in cases of impetus-progredient and constantly progredient course, whereas in respect to cortical pathology, the results were almost identical in all three types of psychosis - 95.2% of cases of constantly progredient and 95.6% - of impetus-progredient course. Attention was called to the 'surprising' data of organic brain injury in patients with paranoid and circular form of the disease, as well as in the most benign (from clinical point of view) impetus course. It is assumed that morphologic changes in the brain of schizophrenic patients are a natural phenomenon, but so far have not been a subject of comprehensive studies, maybe because of prejudice or lack of appropriate methods for examination of the brain during life's time. 6 figs., 15 refs

  12. Bone mineral density and computer tomographic measurements in correlation with failure strength of equine metacarpal bones

    Directory of Open Access Journals (Sweden)

    Péter Tóth

    2014-01-01

    Full Text Available Information regarding bone mineral density and fracture characteristics of the equine metacarpus are lacking. The aim of this study was to characterize the relationship between mechanical properties of the equine metacarpal bone and its biomechanical and morphometric properties. Third metacarpal bones were extracted from horses euthanized unrelated to musculoskeletal conditions. In total, bone specimens from 26 front limbs of 13 horses (7.8 ± 5.8 years old including Lipizzaner (n = 5, Hungarian Warmblood (n = 2, Holsteiner (n = 2, Thoroughbred (n = 1, Hungarian Sporthorse (n = 1, Friesian (n = 1, and Shagya Arabian (n = 1 were collected. The horses included 7 mares, 4 stallions and 2 geldings. Assessment of the bone mineral density of the whole bone across four specific regions of interest was performed using dual-energy X-ray absorptiometry. The bones were scanned using a computer tomographic scanner to measure cross-sectional morphometric properties such as bone mineral density and cross-sectional dimensions including cortical area and cortical width. Mechanical properties (breaking force, bending strength, elastic modulus were determined by a 3-point bending test. Significant positive linear correlations were found between the breaking force and bone mineral density of the entire third metacarpal bones (P P P in vivo investigations.

  13. Computed tomographic findings and treatment of a bull with pituitary gland abscess.

    Science.gov (United States)

    Braun, Ueli; Malbon, Alexandra; Kochan, Manon; Riond, Barbara; Janett, Fredi; Iten, Cornelia; Dennler, Matthias

    2017-01-13

    In cattle, the prognosis of brain abscess is unfavourable and treatment is therefore not recommended. To the knowledge of the authors, there has been no report of successful treatment of a brain abscess in cattle.This report describes the clinical, computed tomographic and postmortem findings in a Holstein-Friesian bull with a hypophyseal abscess. The main clinical findings were generalised ataxia, ptyalism, prolapse of the tongue, dropped jaw, dysphagia, head tilt and unilateral ptosis. Cerebrospinal fluid evaluation revealed 2437 leukocytes/µl and severe pleocytosis. CT examination of the head showed a cavitary lesion consistent with an abscess in the hypophysis. Treatment consisted of gentamicin and flunixin meglumine for 3 days and amoxicillin for 40 days. The neurological signs resolved within 8 days of the start of treatment. The bull was slaughtered 11 months later because of infertility, and a postmortem examination was carried out. Histologically, a mild chronic non suppurative meningoencephalitis restricted to the ventral diencephalon was diagnosed. In addition, there was mild to moderate multifocal chronic lymphoplasmacytic hypophysitis with mild multifocal fibrosis. This case report stresses the significance of CT in confirming the clinical and laboratory diagnosis of central nervous system disorders in cattle and for localising brain lesions. Treatment of the brain abscess resulted, with respect to the central nervous disorder, in a successful outcome and was encouraging considering that most cases have an unfavourable prognosis.

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

    Science.gov (United States)

    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.

  15. Computed tomographic (CT) study of watershed area supplied by the posterior inferior cerebellar artery (PICA)

    International Nuclear Information System (INIS)

    Nozaki, Junichi; Hirose, Satoshi; Hosotani, Kazuo; Kubota, Tetsuya; Kubota, Norihiko.

    1990-01-01

    Thirteen patients with clinical and computed tomographic (CT) evidence of cerebellar infarction were examined during 1987-1989. Six patients had onset of cerebellar infarction at ages ranging from 45 to 69, and seven patients had onset at ages over 70. In thirteen cases, we observed infarction in the inferior region of the cerebellum, and we studied these cases. CT demonstrated decreased density in 4 distinct anatomic areas. These areas are listed below, with estimation of the distribution of the hemispheric arteries of the posterior inferior cerebellar artery (PICA): Group 1 - posterior medial area, probably territory of the inferior vermian branch, tonsillar branch and/or medial artery of the hemispheric artery of the PICA; Group 2 - posterior intermediate area, probably territory of the intermediate artery of the hemispheric artery of the PICA; Group 3 - area including both areas of group 1 and group 3; Group 4 - lateral area, just posterior to pyramis, probably territory of the anterior inferior cerebellar artery and/or lateral artery of the hemispheric artery of PICA. The medial and intermedial cerebellar hemispheric segments were most commonly affected but the lateral segment was not. The PICA least frequently supplied the lateral segments. While the anterior inferior cerebellar artery usually anastomoses with the lateral artery of the hemispheric artery of the PICA. These vascular territories may provide good collateral circulation to this segment. And we also estimate the distribution of the PICA by the CT findings. (author)

  16. Anisakiasis presenting to the ED: clinical manifestations, time course, hematologic tests, computed tomographic findings, and treatment.

    Science.gov (United States)

    Takabayashi, Takeshi; Mochizuki, Toshiaki; Otani, Norio; Nishiyama, Kei; Ishimatsu, Shinichi

    2014-12-01

    The prevalence of anisakiasis is rare in the United States and Europe compared with that in Japan, with few reports of its presentation in the emergency department (ED). This study describes the clinical, hematologic, computed tomographic (CT) characteristics, and treatment in gastric and small intestinal anisakiasis patients in the ED. We retrospectively reviewed the data of 83 consecutive anisakiasis presentations in our ED between 2003 and 2012. Gastric anisakiasis was endoscopically diagnosed with the Anisakis polypide. Small intestinal anisakiasis was diagnosed based on both hematologic (Anisakis antibody) and CT findings. Of the 83 cases, 39 had gastric anisakiasis and 44 had small intestinal anisakiasis based on our diagnostic criteria. Although all patients had abdominal pain, the gastric anisakiasis group developed symptoms significantly earlier (peaking within 6 hours) than the small intestinal anisakiasis group (peaking within 48 hours), and fewer patients with gastric anisakiasis needed admission therapy (5% vs 57%, Pfindings revealed edematous wall thickening in all patients, and ascites and phlegmon of the mesenteric fat were more frequently observed in the small intestinal anisakiasis group. In the ED, early and accurate diagnosis of anisakiasis is important to treat and explain to the patient, and diagnosis can be facilitated by a history of raw seafood ingestion, evaluation of the time-to-symptom development, and classic CT findings. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Computed tomographic fluoroscopy-guided transthoracic needle biopsy for diagnosis of pulmonary nodules

    International Nuclear Information System (INIS)

    Hirose, Takashi; Mori, Kiyoshi; Machida, Suguru; Tominaga, Keigo; Yokoi, Kohei; Adachi, Mitsuru

    2000-01-01

    The purpose of this study was to evaluate the usefulness of computed tomographic (CT) fluoroscopy-guided transthoracic needle biopsy (TTNB) with an 18-gauge automatic biopsy gun for the diagnosis of pulmonary nodules. Between March 1996 and January 1998, 50 patients in whom pulmonary lesions could not be diagnosed cytopathologically with fiberoptic bronchoscopy or were not clearly visualized with fluoroscopy underwent CT fluoroscopy-guided TTNB. Final pathological diagnoses were 23 lung carcinomas, five pulmonary metastases and 22 benign lesions. Sufficient tissue for analysis was obtained from 48 of the 50 lesions (96%). The overall diagnostic yield of CT fluoroscopy-guided TTNB was 90%. The sensitivity, specificity and accuracy for malignancy were 89%, 100% and 94%, respectively. In 20 of the 22 cases (91%) of benign lesions, histological analysis yielded correct and specific diagnoses. Complications occurred in 22 of the 50 cases (44%). The most common complication was pneumothorax, which occurred in 21 of the 50 cases (42%). Chest tube insertion was required in 6 (12%). Although CT fluoroscopy could not decrease the complication rate, CT fluoroscopy-guided TTNB with an automatic biopsy gun appears to be a promising technique for diagnosing pulmonary lesions, particularly benign lesions. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. The great imitator: IgG4 periaortitis masquerading as an acute aortic syndrome on computed tomographic angiography

    OpenAIRE

    Moore, Drew W.; Hansen, Neil J.; DiMaio, Dominick J.; Harrison, William L.

    2016-01-01

    We present the case of a 52-year-old woman who presented to the emergency department with chest and neck pain. Initial cervical spine magnetic resonance imaging shows an abnormal flow void in the left vertebral artery, which prompted a computed tomographic angiogram. This demonstrated a hyperdense thickened ascending aortic wall, which extended into the great vessel origins. Clinically and radiographically interpreted as an acute aortic syndrome and/or intramural hematoma, the patient underwe...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-06-01

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

  1. Permeability Surface of Deep Middle Cerebral Artery Territory on Computed Tomographic Perfusion Predicts Hemorrhagic Transformation After Stroke.

    Science.gov (United States)

    Li, Qiao; Gao, Xinyi; Yao, Zhenwei; Feng, Xiaoyuan; He, Huijin; Xue, Jing; Gao, Peiyi; Yang, Lumeng; Cheng, Xin; Chen, Weijian; Yang, Yunjun

    2017-09-01

    Permeability surface (PS) on computed tomographic perfusion reflects blood-brain barrier permeability and is related to hemorrhagic transformation (HT). HT of deep middle cerebral artery (MCA) territory can occur after recanalization of proximal large-vessel occlusion. We aimed to determine the relationship between HT and PS of deep MCA territory. We retrospectively reviewed 70 consecutive acute ischemic stroke patients presenting with occlusion of the distal internal carotid artery or M1 segment of the MCA. All patients underwent computed tomographic perfusion within 6 hours after symptom onset. Computed tomographic perfusion data were postprocessed to generate maps of different perfusion parameters. Risk factors were identified for increased deep MCA territory PS. Receiver operating characteristic curve analysis was performed to calculate the optimal PS threshold to predict HT of deep MCA territory. Increased PS was associated with HT of deep MCA territory. After adjustments for age, sex, onset time to computed tomographic perfusion, and baseline National Institutes of Health Stroke Scale, poor collateral status (odds ratio, 7.8; 95% confidence interval, 1.67-37.14; P =0.009) and proximal MCA-M1 occlusion (odds ratio, 4.12; 95% confidence interval, 1.03-16.52; P =0.045) were independently associated with increased deep MCA territory PS. Relative PS most accurately predicted HT of deep MCA territory (area under curve, 0.94; optimal threshold, 2.89). Increased PS can predict HT of deep MCA territory after recanalization therapy for cerebral proximal large-vessel occlusion. Proximal MCA-M1 complete occlusion and distal internal carotid artery occlusion in conjunction with poor collaterals elevate deep MCA territory PS. © 2017 American Heart Association, Inc.

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  3. Projection computation based on pixel in simultaneous algebraic reconstruction technique

    International Nuclear Information System (INIS)

    Wang Xu; Chen Zhiqiang; Xiong Hua; Zhang Li

    2005-01-01

    SART is an important arithmetic of image reconstruction, in which the projection computation takes over half of the reconstruction time. An efficient way to compute projection coefficient matrix together with memory optimization is presented in this paper. Different from normal method, projection lines are located based on every pixel, and the following projection coefficient computation can make use of the results. Correlation of projection lines and pixels can be used to optimize the computation. (authors)

  4. Objective functions for tomographic reconstruction from randoms-precorrected PET scans

    International Nuclear Information System (INIS)

    Yavuz, M.; Fessler, J.A.

    1996-01-01

    In PET, usually the data are precorrected for accidental coincidence (AC) events by real-time subtraction of the delayed window coincidences. Randoms subtraction compensates in mean for AC events but destroys the Poisson statistics. Furthermore, for transmission tomography the weighted least-squares (WLS) method leads to systematic biases, especially at low count rates. We propose a new open-quotes shiftedclose quotes Poisson (SP) model for precorrected PET data, which properly matches the first and second order moments of the measurement statistics. Using simulations and analytic approximations, we show that estimators based on the open-quotes ordinaryclose quotes Poisson (OP) model for the precorrected data lead to higher standard deviations than the proposed method. Moreover, if one zero-thresholds the data before applying the maximization algorithm, the OP model results in systematic bias. It is shown that the proposed SP model leads to penalized-likelihood estimates free of systematic bias, even for zero-thresholded data. The proposed SP model does not increase the computation requirements compared to OP model and it is robust to errors in the estimates of the AC event rates

  5. Looking for the Signal: A guide to iterative noise and artefact removal in X-ray tomographic reconstructions of porous geomaterials

    Science.gov (United States)

    Bruns, S.; Stipp, S. L. S.; Sørensen, H. O.

    2017-07-01

    X-ray micro- and nanotomography has evolved into a quantitative analysis tool rather than a mere qualitative visualization technique for the study of porous natural materials. Tomographic reconstructions are subject to noise that has to be handled by image filters prior to quantitative analysis. Typically, denoising filters are designed to handle random noise, such as Gaussian or Poisson noise. In tomographic reconstructions, noise has been projected from Radon space to Euclidean space, i.e. post reconstruction noise cannot be expected to be random but to be correlated. Reconstruction artefacts, such as streak or ring artefacts, aggravate the filtering process so algorithms performing well with random noise are not guaranteed to provide satisfactory results for X-ray tomography reconstructions. With sufficient image resolution, the crystalline origin of most geomaterials results in tomography images of objects that are untextured. We developed a denoising framework for these kinds of samples that combines a noise level estimate with iterative nonlocal means denoising. This allows splitting the denoising task into several weak denoising subtasks where the later filtering steps provide a controlled level of texture removal. We describe a hands-on explanation for the use of this iterative denoising approach and the validity and quality of the image enhancement filter was evaluated in a benchmarking experiment with noise footprints of a varying level of correlation and residual artefacts. They were extracted from real tomography reconstructions. We found that our denoising solutions were superior to other denoising algorithms, over a broad range of contrast-to-noise ratios on artificial piecewise constant signals.

  6. Computer supported individual reconstruction of the mandible

    International Nuclear Information System (INIS)

    Zeilhofer, H.F.; Sader, R.; Horch, H.H.; Kirsten, R.; Wunderlich, A.P.; Lenz, M.

    1995-01-01

    3D visualization of CT sectional images in a video workstation with a medical imaging analysis system is very helpful to the surgeon in the selection of the optimal donor site for autogenous grafts. The sites of interest were represented on the monitor as free, interactively movable objects which could be observed three-dimensionally from all perspectives. By means of superimposition, turning and penetration of these objects the ideal donor site for the graft, in the examples parts from the left and right iliac crest, could be determined. An additional method for this determination is computer assisted generation of a graft pattern from the CT data set for cases where no graftable object in the volume of interest can be found. In a special procedure a graft from bio-compatible material can then be duplicated from this pattern. A reconstructive operation with 3D planning was performed on 12 patients with osseous defects in the area of the jaws and facial cranium. In the search for appropriate grafts from the patient's own body the iliac crest, with its specific volume, was selected for all patients

  7. Novel approach for tomographic reconstruction of gas concentration distributions in air: Use of smooth basis functions and simulated annealing

    Science.gov (United States)

    Drescher, A. C.; Gadgil, A. J.; Price, P. N.; Nazaroff, W. W.

    Optical remote sensing and iterative computed tomography (CT) can be applied to measure the spatial distribution of gaseous pollutant concentrations. We conducted chamber experiments to test this combination of techniques using an open path Fourier transform infrared spectrometer (OP-FTIR) and a standard algebraic reconstruction technique (ART). Although ART converged to solutions that showed excellent agreement with the measured ray-integral concentrations, the solutions were inconsistent with simultaneously gathered point-sample concentration measurements. A new CT method was developed that combines (1) the superposition of bivariate Gaussians to represent the concentration distribution and (2) a simulated annealing minimization routine to find the parameters of the Gaussian basis functions that result in the best fit to the ray-integral concentration data. This method, named smooth basis function minimization (SBFM), generated reconstructions that agreed well, both qualitatively and quantitatively, with the concentration profiles generated from point sampling. We present an analysis of two sets of experimental data that compares the performance of ART and SBFM. We conclude that SBFM is a superior CT reconstruction method for practical indoor and outdoor air monitoring applications.

  8. Simulation studies on the tomographic reconstruction of the equatorial and low-latitude ionosphere in the context of the Indian tomography experiment: CRABEX

    Directory of Open Access Journals (Sweden)

    S. V. Thampi

    2004-11-01

    Full Text Available Equatorial ionosphere poses a challenge to any algorithm that is used for tomographic reconstruction because of the phenomena like the Equatorial Ionization Anomaly (EIA and Equatorial Spread F (ESF. Any tomographic reconstruction of ionospheric density distributions in the equatorial region is not acceptable if it does not image these phenomena, which exhibit large spatial and temporal variability, to a reasonable accuracy. The accuracy of the reconstructed image generally depends on many factors, such as the satellite-receiver configuration, the ray path modelling, grid intersections and finally, the reconstruction algorithm. The present simulation study is performed to examine these in the context of the operational Coherent Radio Beacon Experiment (CRABEX network just commenced in India. The feasibility of using this network for the studies of the equatorial and low-latitude ionosphere over Indian longitudes has been investigated through simulations. The electron density distributions that are characteristic of EIA and ESF are fed into various simulations and the reconstructed tomograms are investigated in terms of their reproducing capabilities. It is seen that, with the present receiver chain existing from 8.5° N to 34° N, it would be possible to obtain accurate images of EIA and the plasma bubbles. The Singular Value Decomposition (SVD algorithm has been used for the inversion procedure in this study. As is known, by the very nature of ionospheric tomography experiments, the received data contain various kinds of errors, like the measurement and discretization errors. The sensitivity of the inversion algorithm, SVD in the present case, to these errors has also been investigated and quantified.

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

    International Nuclear Information System (INIS)

    Blondin, D.; Lanzman, R.; Schellhammer, F.; Oels, M.; Grotemeyer, D.; Baldus, S.E.; Rump, L.C.; Sandmann, W.; Voiculescu, A.

    2010-01-01

    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.

  10. Paraquat-poisoning in the rabbit lungs: high resolution computed tomographic findings and pathologic correlation

    International Nuclear Information System (INIS)

    Lee, Kyung Soo; Kim, Eui Han; Lee, Byoung Ho; Kim, Kun Sang

    1992-01-01

    The authors evaluated high resolution computed tomographic (HRCT) findings of the isolated rabbit lungs with paraquat poisoning, and the findings were correlated with pathologic specimens. The purposes of this study are 1) to obtain the HRCT findings of the normal rabbit lung. 2) to find out if pulmonary pathology can be induced in rabbits by paraquat, and 3) to correlate the HRCT findings to those of pathology. Thirty rabbits were divided into three groups: group I included four control rabbits; group II included 16 rabbits given paraquat intraperitoneally (IP group); and group III included 10 rabbits given paraquat intravenously (IV group). The rabbits were sacrificed seven, 10, and 14 days after injection of various amount of paraquat, and then the lungs were isolated for HRCT and pathologic studies. Gross and microscopic findings of the three groups of control and paraquat-injected rabbit lungs were correlated with HRCT findings. Pulmonary congestion, mild thickening of alveolar walls and septae, and multifocal micro-atelectasis were the man pathologic findings of the lungs in both groups of the rabbits. Pulmonary hemorrhage was noted in five (31%) of 16 rabbits of IP group and three (30%) of 10 IV group. Pulmonary edema was seen in one rabbits (6%) of IP and four (40%) of IV group. Typical pulmonary fibrosis was seen in one rabbit of IP (6%) and IV (10%) group, respectively. There was no correlation between the amount of paraquat and frequency of the pulmonary pathology. Pulmonary fibrosis was seen at least one week after the paraquat injection. On HRCT, pulmonary hemorrhage and edema appeared as diffuse air-space consolidation and pulmonary fibrosis as linear or band-like opacities. However, minimal changes such as mild congestion

  11. Computed Tomographic Virtual Colonoscopy to Screen for Colorectal Neoplasia in asymptomatic adults

    International Nuclear Information System (INIS)

    Pickhardt, Perry J.; Choi, J Richard; Hwang, Inku and others

    2004-01-01

    We evaluated the performance characteristics of computed tomographic (CT) virtual colonospy for the detection of colorectal neoplasia in an average-risk screening population. A total of 1233 symptomatic adults (mean age, 57.8 years) underwent same-day virtual and optical colonoscopy. Radiologists used the three-dimensional endoluminal display for the initial detection of polyps on CT virtual colonoscopy. For the initial examination of each colonic segment, the colonoscopists were unaware of the findings on virtual colonoscopy, which were revealed to them before any subsequent reexamination. The sensitivity and specificity of virtual colonoscopy and the sensitivity of optical colonoscopy were calculated with the use of the findings of the final, unblinded optical colonoscopy as the reference standard. The sensitivity of virtual colonoscopy for adenomatous polyps was 93.8 percent for polyps at least 10 mm in diameter, 93.9 percent for polyps at least 8 mm in diameter, and 88.7 percent for polyps at least 6 mm in diameter. The sensitivity of optical colonoscopy for adenomatous polyps was 87.5 percent, 91.5 percent, and 92.3 percent for the three sizes of polyps, respectively. The specificity of virtual colonoscopy for adenomatous polyps was 96.0 percent for polyps at least 10 mm in diameter, 92.2 percent for polyps at least 8 mm in diameter, and 79.6 percent for polyps at least 6 mm in diameter.Two polyps were malignant; both were detected on virtual colonoscopy, and one of them was missed on optical colonoscopy before the results on virtual colonoscopy were revealed. CT virtual colonoscopy with the use of a three-dimensional approach is an accurate screening method for the detection of colorectal neoplasia in symptomatic average-risk adults and compares favorably with optical colonoscopy in terms of the detection of clinically relevant lesions

  12. Detection of intra-cardiac thrombi and congestive heart failure in cats using computed tomographic angiography.

    Science.gov (United States)

    Vititoe, Kyle P; Fries, Ryan C; Joslyn, Stephen; Selmic, Laura E; Howes, Mark; Vitt, Jordan P; O'Brien, Robert T

    2018-04-16

    Arterial thromboembolism is a life-threatening condition in cats most commonly secondary to cardiac disease. Echocardiography is the reference standard to evaluate for presence of a thrombus. In humans, computed tomographic (CT) angiography is becoming widely used to detect left atrial thrombi precluding the use of sedation. The purpose of this prospective, controlled, methods comparison pilot study was threefold: (1) describe new CT angiography protocol used in awake cats with cardiac disease and congestive heart failure; (2) determine accuracy of continuous and dynamic acquisition CT angiography to identify and characterize cardiac thrombi from spontaneous echocardiographic contrast using transthoracic echocardiography as our reference standard; (3) identify known negative prognostic factors and comorbidities of the thorax that CT angiography may provide that complement or supersede echocardiographic examination. Fourteen cats with heart disease were recruited; 7 with thrombi and 7 with spontaneous echocardiographic contrast. Echocardiography and awake CT angiography were performed using a microdose of contrast. Six of 7 thrombi were identified on CT angiography as filling defects by at least one reviewer within the left auricle (n = 6) and right heart (n = 1). Highest sensitivity (71.4%) was in continuous phase and highest specificity (85.7%) was in dynamic studies with fair to moderate interobserver agreement (0.38 and 0.44). CT angiography identified prognostic cardiac information (left atrial enlargement, congestive heart failure, arterial thromboembolism) and comorbidities (suspected idiopathic pulmonary fibrosis, asthma). This study indicates CT angiography can readily identify cardiac thrombi, important prognostic information and comorbidities, and can be safely performed in cats with cardiac disease and congestive heart failure. © 2018 American College of Veterinary Radiology.

  13. Clinical observations of the brain abscesses, especially on the computed tomographic brain scan findings

    International Nuclear Information System (INIS)

    Kitano, Masahiko; Kuroda, Ryotaro; Yamada, Yasufumi; Yorimae, Akira; Akai, Fumiharu; Watanabe, Masaru; Nakatani, Jiro; Ioku, Masahiko

    1988-01-01

    Fifteen cases with pyogenic brain abscess were experienced in our clinic during the last 7 years. The records of these patients were examined to evaluate the clinical stage and the result of several treatments. In 12 operative cases, diagnosis was made by fluid aspirated from the abscess. Bacteria were cultured from the fluid in 5 among these cases. In 3 other non-operative patients, diagnosis was based on computed tomographic (CT) brain scans and laboratory studies. Each volume of the brain abscess and surrounding brain edema was measured on serial CT scans to evaluate the clinical stage and the abscess evolution. In symptoms and signs, it has been thought that one of the factors contributing to mortality was the level of consciousness. In this study, the disturbance of consciousness did not correlate with the size of abscess, but with that of edema. The cases reported here were divided into 3 groups according to the volume of abscess and of edema on initial CT scans. The cases of group A had small surrounding edema ( 50 ml) and small abscess ( 25 ml). The group A had slight change in the clinical status and the size of edema, but the others had severe change. Three phase changes in edema size were seen in the group B regardless of therapeutic modalities ; showing almost constant increase in first 2 weeks, great decrease in second 2 weeks and moderate decrease following these 4 weeks. In the group C, however, these phases were seen only in early operation cases. (J.P.N.)

  14. Computed tomographic colonography (CTC) performance: one-year clinical follow-up

    International Nuclear Information System (INIS)

    Duff, S.E.; Murray, D.; Rate, A.J.; Richards, D.M.; Kumar, N.A. Mahesh

    2006-01-01

    Aim: Computed tomographic colonography (CTC) represents a valuable advance in imaging technology for patients with colonic symptoms who are unfit for or fail to complete investigation with conventional techniques of colonoscopy or barium enema. The aim of this study was to examine whether CTC was sufficient to exclude colorectal cancer in such a population. As our patients were unfit for or unable to complete conventional investigations, we used 1 year clinical follow-up to exclude colonic malignancy. Materials and Methods: CTC examination was performed using multi-slice CT in patients fitting pre-determined criteria. All patients who had completed 12 months of follow-up after CTC were included. Data were extracted from patient records and lack of presentation within the 12 months following a negative CTC was assumed to equate to lack of colorectal cancer at initial investigation. Results: One hundred and twelve patients underwent CTC with a median age of 78 years (range 39-95) and median follow-up of 18 months (range 12-26). CTC detected 7 colorectal cancers, with 3 false positives and 1 false negative, giving a sensitivity of 87.5% and specificity of 97.1% for the detection of colorectal cancer. Conclusions: CTC is a good imaging tool for the exclusion of colorectal cancer in a population unfit for or unable to complete colonoscopy or barium enema, with reasonable sensitivity and specificity for detection of colorectal cancer. However, the optimum investigative strategy for fitter symptomatic individuals is still debated and should be clarified by the results of ongoing randomised controlled trials

  15. Cost-Effectiveness of Computed Tomographic Colonography: A Prospective Comparison with Colonoscopy

    International Nuclear Information System (INIS)

    Arnesen, R.B.; Ginnerup-Pedersen, B.; Poulsen, P.B.; Benzon, K. von; Adamsen, S.; Laurberg, S.; Hart-Hansen, O.

    2007-01-01

    Purpose: To estimate the cost-effectiveness of detecting colorectal polyps with computed tomographic colonography (CTC) and subsequent polypectomy with primary colonoscopy (CC), using CC as the alternative strategy. Material and Methods: A marginal analysis was performed regarding 103 patients who had had CTC prior to same-day CC at two hospitals, H-I (n 53) and H-II (n = 50). The patients were randomly chosen from surveillance and symptomatic study populations (148 at H-I and 231 at H-II). Populations, organizations, and procedures were compared. Cost data on time consumption, medication, and minor equipment were collected prospectively, while data on salaries and major equipment were collected retrospectively. The effect was the (previously published) sensitivities of CTC and CC for detection of colorectal polyps ≥6 mm (H-I, n = 148) or ≥5 mm (H-II, n = 231). Results: Thirteen patients at each center had at least one colorectal polyp ≥6 mm or ≥5 mm. CTC was the cost-effective alternative at H-I (Euro 187 vs. Euro 211), while CC was the cost-effective alternative at H-II (Euro 239 vs. Euro 192). The cost-effectiveness (costs per finding) mainly depended on the sensitivity of CTC and CC, but the depreciation of equipment and the staff's use of time were highly influential as well. Conclusion: Detection of colorectal polyps ≥6 mm or ≥5 mm with CTC, followed by polypectomy by CC, can be performed cost-effectively at some institutions with the appropriate hardware and organization keywords

  16. Availability, Indications, and Technical Performance of Computed Tomographic Colonography: A National Survey

    International Nuclear Information System (INIS)

    Fisichella, V.; Hellstroem, M.

    2006-01-01

    Purpose: To determine the availability, indications, and technique of computed tomographic colonography (CTC) in Sweden and to investigate opinions on its future role in colon imaging. Material and Methods: In May 2004, a questionnaire on CTC was mailed to all Departments of Radiology in Sweden, and one year later a telephone interview was conducted with the departments that intended to start a CTC service. Results: Ninety-nine departments (83%) answered the questionnaire, indicating that 23/99 (23.2%) offered a CTC service. Reasons for non-implementation of CTC were lack of CTC training in 34/73 (46.6%) and non-availability of multi-detector row CT scanners in 33/73 (45.2%), while 26% were awaiting further scientific documentation on CTC. Incomplete colonoscopy was the main indication for CTC in 21/23 (91.3%) departments performing CTC. Dual positioning, room air insufflation, and thin-slice collimation were used in all the responding departments. The number of CTC studies performed varied from 1-5 (26.1%) to more than 200 (17.4%). Intravenous contrast material was routinely administered by 9/23 (39.1%) departments. Out of 30 (39.5%) departments that in 2004 intended to start CTC, 9 (30%) had done so by June 2005. A total of 32/99 (32.3%) departments had therefore started CTC by June 2005. Half of the departments that replied believed that CTC would absolutely or probably replace barium enema in the future. Conclusion: The survey shows relatively limited diffusion of CTC practice in Sweden, with approximately one-third of radiology departments offering a CTC service, mostly on a small scale. A wider dissemination of CTC requires further scientific documentation of its capability, intensified educational efforts, and additional funding

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. Computed Tomographic Angiography of the Pancreas in Cats with Chronic Diabetes Mellitus Compared to Normal Cats.

    Science.gov (United States)

    Secrest, S; Sharma, A; Bugbee, A

    2018-03-02

    Diabetes mellitus (DM) is a common endocrinopathy in cats. No known diagnostic test or patient characteristic at the time of diagnosis can predict likely disease course, unlike in people in whom computed tomographic angiography (CTA) is used. No published data exist regarding the CTA appearance of the pancreas in cats with DM, and thus, it is unknown what if any CTA variables should be further assessed for associations with pancreatic endocrine function. A significant difference in pancreatic attenuation, volume, and size will be identified between normal cats and those with chronic DM on CTA. Ten healthy control cats and 15 cats with naturally occurring DM present for >12 months. Prospective cross-sectional study comparing pancreatic attenuation, enhancement pattern, size, volume, pancreatic volume-to-body weight ratio (V:BW), pancreatic arterial: portal phase ratio (A:P), time-to-arterial enhancement, and time-to-peak portal enhancement on CTA between sedated healthy control cats and those with chronic DM. The pancreas in cats with chronic DM was significantly larger, had higher volume, higher V:BW, and shorter time-to-peak portal enhancement on CTA when compared to normal cats. Peak portal enhancement time, pancreatic size, pancreatic volume, and V:BW can be used to differentiate normal sedated cats from those with chronic DM by CTA. These variables warrant further investigation to identify possible associations with endocrine function. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

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

    International Nuclear Information System (INIS)

    Gazzoni, Fernando Ferreira; Hochhegger, Bruno; Severo, Luiz Carlos; Marchiori, Edson; Pasqualotto, Alessandro; Sartori, Ana Paula Garcia; Schio, Sadi; Camargo, José

    2014-01-01

    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

  1. Image quality on dual-source computed-tomographic coronary angiography

    International Nuclear Information System (INIS)

    Rixe, Johannes; Rolf, Andreas; Conradi, Guido; Elsaesser, Albrecht; Moellmann, Helge; Nef, Holger M.; Hamm, Christian W.; Dill, Thorsten; Bachmann, Georg

    2008-01-01

    Multi-detector CT reliably permits visualization of coronary arteries, but due to the occurrence of motion artefacts at heart rates >65 bpm caused by a temporal resolution of 165 ms, its utilisation has so far been limited to patients with a preferably low heart rate. We investigated the assessment of image quality on computed tomography of coronary arteries in a large series of patients without additional heart rate control using dual-source computed tomography (DSCT). DSCT (Siemens Somatom Definition, 83-ms temporal resolution) was performed in 165 consecutive patients (mean age 64±11.4 years) after injection of 60-80 ml of contrast. Data sets were reconstructed in 5% intervals of the cardiac cycle and evaluated by two readers in consensus concerning evaluability of the coronary arteries and presence of motion and beam-hardening artefacts using the AHA 16-segment coronary model. Mean heart rate during CT was 65±10.5 bpm; visualisation without artefacts was possible in 98.7% of 2,541 coronary segments. Only two segments were considered unevaluable due to cardiac motion; 30 segments were unassessable due to poor signal-to-noise ratio or coronary calcifications (both n=15). Data reconstruction at 65-70% of the cardiac cycle provided for the best image quality. For heart rates >85 bpm, a systolic reconstruction at 45% revealed satisfactory results. Compared with earlier CT generations, DSCT provides for non-invasive coronary angiography with diagnostic image quality even at heart rates >65 bpm and thus may broaden the spectrum of patients that can be investigated non-invasively. (orig.)

  2. Multidetector computed tomographic pulmonary angiography in patients with a high clinical probability of pulmonary embolism.

    Science.gov (United States)

    Moores, L; Kline, J; Portillo, A K; Resano, S; Vicente, A; Arrieta, P; Corres, J; Tapson, V; Yusen, R D; Jiménez, D

    2016-01-01

    ESSENTIALS: When high probability of pulmonary embolism (PE), sensitivity of computed tomography (CT) is unclear. We investigated the sensitivity of multidetector CT among 134 patients with a high probability of PE. A normal CT alone may not safely exclude PE in patients with a high clinical pretest probability. In patients with no clear alternative diagnosis after CTPA, further testing should be strongly considered. Whether patients with a negative multidetector computed tomographic pulmonary angiography (CTPA) result and a high clinical pretest probability of pulmonary embolism (PE) should be further investigated is controversial. This was a prospective investigation of the sensitivity of multidetector CTPA among patients with a priori clinical assessment of a high probability of PE according to the Wells criteria. Among patients with a negative CTPA result, the diagnosis of PE required at least one of the following conditions: ventilation/perfusion lung scan showing a high probability of PE in a patient with no history of PE, abnormal findings on venous ultrasonography in a patient without previous deep vein thrombosis at that site, or the occurrence of venous thromboembolism (VTE) in a 3-month follow-up period after anticoagulation was withheld because of a negative multidetector CTPA result. We identified 498 patients with a priori clinical assessment of a high probability of PE and a completed CTPA study. CTPA excluded PE in 134 patients; in these patients, the pooled incidence of VTE was 5.2% (seven of 134 patients; 95% confidence interval [CI] 1.5-9.0). Five patients had VTEs that were confirmed by an additional imaging test despite a negative CTPA result (five of 48 patients; 10.4%; 95% CI 1.8-19.1), and two patients had objectively confirmed VTEs that occurred during clinical follow-up of at least 3 months (two of 86 patients; 2.3%; 95% CI 0-5.5). None of the patients had a fatal PE during follow-up. A normal multidetector CTPA result alone may not safely

  3. Effects of megavoltage computed tomographic scan methodology on setup verification and adaptive dose calculation in helical TomoTherapy.

    Science.gov (United States)

    Zhu, Jian; Bai, Tong; Gu, Jiabing; Sun, Ziwen; Wei, Yumei; Li, Baosheng; Yin, Yong

    2018-04-27

    To evaluate the effect of pretreatment megavoltage computed tomographic (MVCT) scan methodology on setup verification and adaptive dose calculation in helical TomoTherapy. Both anthropomorphic heterogeneous chest and pelvic phantoms were planned with virtual targets by TomoTherapy Physicist Station and were scanned with TomoTherapy megavoltage image-guided radiotherapy (IGRT) system consisted of six groups of options: three different acquisition pitches (APs) of 'fine', 'normal' and 'coarse' were implemented by multiplying 2 different corresponding reconstruction intervals (RIs). In order to mimic patient setup variations, each phantom was shifted 5 mm away manually in three orthogonal directions respectively. The effect of MVCT scan options was analyzed in image quality (CT number and noise), adaptive dose calculation deviations and positional correction variations. MVCT scanning time with pitch of 'fine' was approximately twice of 'normal' and 3 times more than 'coarse' setting, all which will not be affected by different RIs. MVCT with different APs delivered almost identical CT numbers and image noise inside 7 selected regions with various densities. DVH curves from adaptive dose calculation with serial MVCT images acquired by varied pitches overlapped together, where as there are no significant difference in all p values of intercept & slope of emulational spinal cord (p = 0.761 & 0.277), heart (p = 0.984 & 0.978), lungs (p = 0.992 & 0.980), soft tissue (p = 0.319 & 0.951) and bony structures (p = 0.960 & 0.929) between the most elaborated and the roughest serials of MVCT. Furthermore, gamma index analysis shown that, compared to the dose distribution calculated on MVCT of 'fine', only 0.2% or 1.1% of the points analyzed on MVCT of 'normal' or 'coarse' do not meet the defined gamma criterion. On chest phantom, all registration errors larger than 1 mm appeared at superior-inferior axis, which cannot be avoided with the smallest AP and RI

  4. Discrete tomographic reconstruction of 2D polycrystal orientation maps from X-ray diffraction projections using Gibbs priors

    DEFF Research Database (Denmark)

    Rodek, L.; Knudsen, E.; Poulsen, H.F.

    2005-01-01

    discrete tomographic algorithm, applying image-modelling Gibbs priors and a homogeneity condition. The optimization of the objective function is accomplished via the Gibbs Sampler in conjunction with simulated annealing. In order to express the structure of the orientation map, the similarity...

  5. Analysis of iterative region-of-interest image reconstruction for x-ray computed tomography

    Science.gov (United States)

    Sidky, Emil Y.; Kraemer, David N.; Roth, Erin G.; Ullberg, Christer; Reiser, Ingrid S.; Pan, Xiaochuan

    2014-01-01

    Abstract. One of the challenges for iterative image reconstruction (IIR) is that such algorithms solve an imaging model implicitly, requiring a complete representation of the scanned subject within the viewing domain of the scanner. This requirement can place a prohibitively high computational burden for IIR applied to x-ray computed tomography (CT), especially when high-resolution tomographic volumes are required. In this work, we aim to develop an IIR algorithm for direct region-of-interest (ROI) image reconstruction. The proposed class of IIR algorithms is based on an optimization problem that incorporates a data fidelity term, which compares a derivative of the estimated data with the available projection data. In order to characterize this optimization problem, we apply it to computer-simulated two-dimensional fan-beam CT data, using both ideal noiseless data and realistic data containing a level of noise comparable to that of the breast CT application. The proposed method is demonstrated for both complete field-of-view and ROI imaging. To demonstrate the potential utility of the proposed ROI imaging method, it is applied to actual CT scanner data. PMID:25685824

  6. Analysis of iterative region-of-interest image reconstruction for x-ray computed tomography.

    Science.gov (United States)

    Sidky, Emil Y; Kraemer, David N; Roth, Erin G; Ullberg, Christer; Reiser, Ingrid S; Pan, Xiaochuan

    2014-10-03

    One of the challenges for iterative image reconstruction (IIR) is that such algorithms solve an imaging model implicitly, requiring a complete representation of the scanned subject within the viewing domain of the scanner. This requirement can place a prohibitively high computational burden for IIR applied to x-ray computed tomography (CT), especially when high-resolution tomographic volumes are required. In this work, we aim to develop an IIR algorithm for direct region-of-interest (ROI) image reconstruction. The proposed class of IIR algorithms is based on an optimization problem that incorporates a data fidelity term, which compares a derivative of the estimated data with the available projection data. In order to characterize this optimization problem, we apply it to computer-simulated two-dimensional fan-beam CT data, using both ideal noiseless data and realistic data containing a level of noise comparable to that of the breast CT application. The proposed method is demonstrated for both complete field-of-view and ROI imaging. To demonstrate the potential utility of the proposed ROI imaging method, it is applied to actual CT scanner data.

  7. Computed tomographic analysis of temporal maxillary stability and pterygomaxillary generate formation following pediatric Le Fort III distraction advancement.

    Science.gov (United States)

    Hopper, Richard A; Sandercoe, Gavin; Woo, Albert; Watts, Robyn; Kelley, Patrick; Ettinger, Russell E; Saltzman, Babette

    2010-11-01

    Le Fort III distraction requires generation of bone in the pterygomaxillary region. The authors performed retrospective digital analysis on temporal fine-cut computed tomographic images to quantify both radiographic evidence of pterygomaxillary region bone formation and relative maxillary stability. Fifteen patients with syndromic midface hypoplasia were included in the study. The average age of the patients was 8.7 years; 11 had either Crouzon or Apert syndrome. The average displacement of the maxilla during distraction was 16.2 mm (range, 7 to 31 mm). Digital analysis was performed on fine-cut computed tomographic scans before surgery, at device removal, and at annual follow-up. Seven patients also had mid-consolidation computed tomographic scans. Relative maxillary stability and density of radiographic bone in the pterygomaxillary region were calculated between each scan. There was no evidence of clinically significant maxillary relapse, rotation, or growth between the end of consolidation and 1-year follow-up, other than a relatively small 2-mm subnasal maxillary vertical growth. There was an average radiographic ossification of 0.5 mm/mm advancement at the time of device removal, with a 25th percentile value of 0.3 mm/mm. The time during consolidation that each patient reached the 25th percentile of pterygomaxillary region bone density observed in this series of clinically stable advancements ranged from 1.3 to 9.8 weeks (average, 3.7 weeks). There was high variability in the amount of bone formed in the pterygomaxillary region associated with clinical stability of the advanced Le Fort III segment. These data suggest that a subsection of patients generate the minimal amount of pterygomaxillary region bone formation associated with advancement stability as early as 4 weeks into consolidation.

  8. Class of reconstructed discontinuous Galerkin methods in computational fluid dynamics

    International Nuclear Information System (INIS)

    Luo, Hong; Xia, Yidong; Nourgaliev, Robert

    2011-01-01

    A class of reconstructed discontinuous Galerkin (DG) methods is presented to solve compressible flow problems on arbitrary grids. The idea is to combine the efficiency of the reconstruction methods in finite volume methods and the accuracy of the DG methods to obtain a better numerical algorithm in computational fluid dynamics. The beauty of the resulting reconstructed discontinuous Galerkin (RDG) methods is that they provide a unified formulation for both finite volume and DG methods, and contain both classical finite volume and standard DG methods as two special cases of the RDG methods, and thus allow for a direct efficiency comparison. Both Green-Gauss and least-squares reconstruction methods and a least-squares recovery method are presented to obtain a quadratic polynomial representation of the underlying linear discontinuous Galerkin solution on each cell via a so-called in-cell reconstruction process. The devised in-cell reconstruction is aimed to augment the accuracy of the discontinuous Galerkin method by increasing the order of the underlying polynomial solution. These three reconstructed discontinuous Galerkin methods are used to compute a variety of compressible flow problems on arbitrary meshes to assess their accuracy. The numerical experiments demonstrate that all three reconstructed discontinuous Galerkin methods can significantly improve the accuracy of the underlying second-order DG method, although the least-squares reconstructed DG method provides the best performance in terms of both accuracy, efficiency, and robustness. (author)

  9. Iterative concurrent reconstruction algorithms for emission computed tomography

    International Nuclear Information System (INIS)

    Brown, J.K.; Hasegawa, B.H.; Lang, T.F.

    1994-01-01

    Direct reconstruction techniques, such as those based on filtered backprojection, are typically used for emission computed tomography (ECT), even though it has been argued that iterative reconstruction methods may produce better clinical images. The major disadvantage of iterative reconstruction algorithms, and a significant reason for their lack of clinical acceptance, is their computational burden. We outline a new class of ''concurrent'' iterative reconstruction techniques for ECT in which the reconstruction process is reorganized such that a significant fraction of the computational processing occurs concurrently with the acquisition of ECT projection data. These new algorithms use the 10-30 min required for acquisition of a typical SPECT scan to iteratively process the available projection data, significantly reducing the requirements for post-acquisition processing. These algorithms are tested on SPECT projection data from a Hoffman brain phantom acquired with a 2 x 10 5 counts in 64 views each having 64 projections. The SPECT images are reconstructed as 64 x 64 tomograms, starting with six angular views. Other angular views are added to the reconstruction process sequentially, in a manner that reflects their availability for a typical acquisition protocol. The results suggest that if T s of concurrent processing are used, the reconstruction processing time required after completion of the data acquisition can be reduced by at least 1/3 T s. (Author)

  10. Computed tomographic scanning in patients presenting with chief complaint of headache without focal neurological signs

    International Nuclear Information System (INIS)

    Halim, A.; Khalid, W.; Haq, A.U.

    2017-01-01

    To determine the frequency of positive computed tomographic (CT)scan findings in patients presenting at PNS Shifa Hospital Karachi with chief complaint of headache without focal neurological signs. Study Design: Cross sectional descriptive study. Place and Duration of Study: The study was conducted at the Radiology department, PNS Shifa Hospital Karachi from Dec 2011 to Jun 2012. Patients and Methods: This cross-sectional descriptive study included referred patients with complaint of headache of one month duration or more without focal neurological signs. No gender restriction was considered and patients of age more than 14 years were included. Patients with headache due to other known clinical disorders such as intracranial neoplasm and stroke were excluded. Patients with focal neurological signs such as hemiparesis, cerebellar signs and cranial nerve palsies were also excluded from the study. A total of 105 patients were included in the study through non probability consecutive sampling. Informed written consent was taken from the patients by explaining all the risks and benefits of the study and use of data for research and publication. Plain CT scan brain was done by trained CT technician and reporting of CT scan was done by consultant radiologist. CT scan was done on Toshiba Scanner Aquilion-64 CT Scan machine. The imaging protocol consisted of appropriately angled continuous 5mm thick axial slices for the posterior fossa and 10 mm thick slices for the rest of brain from the base of skull to the vertex. Data was collected through a specially structured proforma. Confidentiality of the patients record was maintained. Results: Majority of the patients were between 31-40 years of age i.e. 29.52 percent (n=31) and mean and SD was calculated as 34.24 +- 8.72 years, 54.29 percent (n=57) females and 45.71 percent (n=48) male patients, frequency of positive CT scan findings in patients with chief complaint of headache without focal neurological signs was recorded as

  11. Clear cell chondrosarcoma: radiographic, computed tomographic, and magnetic resonance findings in 34 patients with pathologic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Mark S.; Koyama, Takashi; Swee, Ronald G.; Inwards, Carrie Y. [Department of Radiology, Mayo Clinic, 200 First Street SW, MN 55905, Rochester (United States)

    2003-12-01

    To describe the radiographic features of clear cell chondrosarcoma (CCCS), including the computed tomographic (CT) and magnetic resonance (MR) findings, and to correlate them with the histopathologic findings. A retrospective review was carried out of 72 patients with histopathologically confirmed CCCS. Imaging studies were available for 34 patients: conventional radiographs (n=28), CT scans (n=14), and MR images (n=15). Radiographic studies were reviewed by three radiologists who rendered a consensus opinion; the studies were correlated with the histopathologic findings. Of the 34 patients with imaging studies, 30 were male and 4 were female (mean age 38.6 years; range 11-74 years). Twenty-two lesions were in long bones (15, proximal femur; 1, distal femur; 1, proximal tibia; 5, proximal humerus) and 11 were in flat bones (5, vertebra; 4, rib; 1, scapula; 1, innominate). One lesion occurred in the tarsal navicular bone. Typically, long bone lesions were located in the epimetaphysis (19/22) and were lucent with a well-defined sclerotic margin and no cortical destruction or periosteal new bone formation. More than one-third of the long bone lesions contained matrix mineralization with a characteristic chondroid appearance. Pathologic fractures were present in six long bone lesions (4, humerus; 2, femur). Lesions in the proximal humerus were more likely to have indistinct margins (4/5) and extend into the diaphysis. Flat bone lesions were typically lytic and expansile and occasionally demonstrated areas of cortical disruption. Typically, matrix mineralization, when present, was amorphous. MR imaging, when available, was superior to conventional radiographs for demonstrating the intramedullary extent of a lesion as well as soft tissue extension. CT images better delineated the presence of cortical destruction and the character of matrix mineralization patterns. CCCS lesions were typically low signal intensity on T1-weighted images and moderately or significantly

  12. Clear cell chondrosarcoma: radiographic, computed tomographic, and magnetic resonance findings in 34 patients with pathologic correlation

    International Nuclear Information System (INIS)

    Collins, Mark S.; Koyama, Takashi; Swee, Ronald G.; Inwards, Carrie Y.

    2003-01-01

    To describe the radiographic features of clear cell chondrosarcoma (CCCS), including the computed tomographic (CT) and magnetic resonance (MR) findings, and to correlate them with the histopathologic findings. A retrospective review was carried out of 72 patients with histopathologically confirmed CCCS. Imaging studies were available for 34 patients: conventional radiographs (n=28), CT scans (n=14), and MR images (n=15). Radiographic studies were reviewed by three radiologists who rendered a consensus opinion; the studies were correlated with the histopathologic findings. Of the 34 patients with imaging studies, 30 were male and 4 were female (mean age 38.6 years; range 11-74 years). Twenty-two lesions were in long bones (15, proximal femur; 1, distal femur; 1, proximal tibia; 5, proximal humerus) and 11 were in flat bones (5, vertebra; 4, rib; 1, scapula; 1, innominate). One lesion occurred in the tarsal navicular bone. Typically, long bone lesions were located in the epimetaphysis (19/22) and were lucent with a well-defined sclerotic margin and no cortical destruction or periosteal new bone formation. More than one-third of the long bone lesions contained matrix mineralization with a characteristic chondroid appearance. Pathologic fractures were present in six long bone lesions (4, humerus; 2, femur). Lesions in the proximal humerus were more likely to have indistinct margins (4/5) and extend into the diaphysis. Flat bone lesions were typically lytic and expansile and occasionally demonstrated areas of cortical disruption. Typically, matrix mineralization, when present, was amorphous. MR imaging, when available, was superior to conventional radiographs for demonstrating the intramedullary extent of a lesion as well as soft tissue extension. CT images better delineated the presence of cortical destruction and the character of matrix mineralization patterns. CCCS lesions were typically low signal intensity on T1-weighted images and moderately or significantly

  13. Computational acceleration for MR image reconstruction in partially parallel imaging.

    Science.gov (United States)

    Ye, Xiaojing; Chen, Yunmei; Huang, Feng

    2011-05-01

    In this paper, we present a fast numerical algorithm for solving total variation and l(1) (TVL1) based image reconstruction with application in partially parallel magnetic resonance imaging. Our algorithm uses variable splitting method to reduce computational cost. Moreover, the Barzilai-Borwein step size selection method is adopted in our algorithm for much faster convergence. Experimental results on clinical partially parallel imaging data demonstrate that the proposed algorithm requires much fewer iterations and/or less computational cost than recently developed operator splitting and Bregman operator splitting methods, which can deal with a general sensing matrix in reconstruction framework, to get similar or even better quality of reconstructed images.

  14. Level-set reconstruction algorithm for ultrafast limited-angle X-ray computed tomography of two-phase flows.

    Science.gov (United States)

    Bieberle, M; Hampel, U

    2015-06-13

    Tomographic image reconstruction is based on recovering an object distribution from its projections, which have been acquired from all angular views around the object. If the angular range is limited to less than 180° of parallel projections, typical reconstruction artefacts arise when using standard algorithms. To compensate for this, specialized algorithms using a priori information about the object need to be applied. The application behind this work is ultrafast limited-angle X-ray computed tomography of two-phase flows. Here, only a binary distribution of the two phases needs to be reconstructed, which reduces the complexity of the inverse problem. To solve it, a new reconstruction algorithm (LSR) based on the level-set method is proposed. It includes one force function term accounting for matching the projection data and one incorporating a curvature-dependent smoothing of the phase boundary. The algorithm has been validated using simulated as well as measured projections of known structures, and its performance has been compared to the algebraic reconstruction technique and a binary derivative of it. The validation as well as the application of the level-set reconstruction on a dynamic two-phase flow demonstrated its applicability and its advantages over other reconstruction algorithms. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  15. Using additive manufacturing in accuracy evaluation of reconstructions from computed tomography.

    Science.gov (United States)

    Smith, Erin J; Anstey, Joseph A; Venne, Gabriel; Ellis, Randy E

    2013-05-01

    Bone models derived from patient imaging and fabricated using additive manufacturing technology have many potential uses including surgical planning, training, and research. This study evaluated the accuracy of bone surface reconstruction of two diarthrodial joints, the hip and shoulder, from computed tomography. Image segmentation of the tomographic series was used to develop a three-dimensional virtual model, which was fabricated using fused deposition modelling. Laser scanning was used to compare cadaver bones, printed models, and intermediate segmentations. The overall bone reconstruction process had a reproducibility of 0.3 ± 0.4 mm. Production of the model had an accuracy of 0.1 ± 0.1 mm, while the segmentation had an accuracy of 0.3 ± 0.4 mm, indicating that segmentation accuracy was the key factor in reconstruction. Generally, the shape of the articular surfaces was reproduced accurately, with poorer accuracy near the periphery of the articular surfaces, particularly in regions with periosteum covering and where osteophytes were apparent.

  16. X-ray and gamma-ray transmission computed tomographic imaging of archaeological objects

    International Nuclear Information System (INIS)

    Jaafar Abdullah; Susan Maria Sipaun

    2004-01-01

    X-ray or gamma-ray transmission computed tomography (CT) is a powerful non-destructive evaluation (NDE) technique that produces two-dimensional cross-section images of an object without the need to physically section it. CT is also known by the acronym CAT, for computerised axial tomography or computed-aided tomography. The invention of CT techniques revolutionised the field of medical diagnostic imaging because it provided more detailed and useful information than any previous non-invasive imaging techniques. The method is increasingly being used in industry, aerospace, geosciences and archaeology. This paper presents a brief overview of X-ray or gamma-ray transmission tomography. It is not intended to be a technical treatise but is hoped that it would raise awareness and promote opportunities for further collaboration amongst the nuclear research community, including archaeologists and those in the conservation profession. The theoretical aspects of CT scanner, the system configurations and the adopted algorithm for image reconstruction are discussed. In addition, a few examples of CT images for archaeological objects are presented. The examples were purposely chosen to illustrate clearly and precisely the fundamental concepts of this sophisticated field. (Author)

  17. Sex Differences in Patients With CAM Deformities With Femoroacetabular Impingement: 3-Dimensional Computed Tomographic Quantification.

    Science.gov (United States)

    Yanke, Adam B; Khair, M Michael; Stanley, Robert; Walton, David; Lee, Simon; Bush-Joseph, Charles A; Espinoza Orías, Alejandro; Espinosa Orias, Alejandro A; Inoue, Nozomu; Nho, Shane J

    2015-12-01

    To determine if significant differences exist between male and female CAM deformities using quantitative 3-dimensional (3D) volume and location analysis. Retrospective analysis of preoperative computed tomographic (CT) scans for 138 femurs (69 from male patients and 69 from female patients) diagnosed with impingement from November 2009 to November 2011 was completed. Those patients who presented with hip complaints and had a history, physical examination (limited range of motion, positive impingement signs), plain radiographs (anteroposterior pelvis, 90° Dunn view, false profile view), and magnetic resonance images consistent with femoroacetabular impingement (FAI) and in whom a minimum of 6 months of conservative therapy (oral anti-inflammatory agents, physical therapy, and activity modification) had failed were indicated for arthroscopic surgery and had a preoperative CT scan. Scans were segmented, converted to point cloud data, and analyzed with a custom-written computer program. Analysis included mean CAM height and volume, head radius, and femoral version. Differences were analyzed using an unpaired t test with significance set at P position ± the 2:51 o'clock position to the 3:28 o'clock position ± the 1:59 o'clock position, with an average span from the 3:06 o'clock position ± the 1:29 o'clock position (male patients, the 11:23 o'clock position ± the 0:46 o'clock position to the 3:05 o'clock position ± the 1:20 o'clock position; female patients, the 11:33 o'clock position ± the 0:37 o'clock position to the 2:27 o'clock position ± the 0:45 o'clock position). There were no differences in the posterior (P = .60) or anterior (P = .14) extent of CAM deformities. However, the span on the clock face of the CAM deformities varied when comparing men with women (male patients, the 3:43 o'clock position ± the 1:29 o'clock position; female patients, the 2:54 o'clock position ± the 1:09 o'clock position; P = .02). Our data show that female CAM deformities

  18. Visual computed tomographic scoring of emphysema and its correlation with its diagnostic electrocardiographic sign: the frontal P vector.

    Science.gov (United States)

    Chhabra, Lovely; Sareen, Pooja; Gandagule, Amit; Spodick, David H

    2012-03-01

    Verticalization of the frontal P vector in patients older than 45 years is virtually diagnostic of pulmonary emphysema (sensitivity, 96%; specificity, 87%). We investigated the correlation of P vector and the computed tomographic visual score of emphysema (VSE) in patients with established diagnosis of chronic obstructive pulmonary disease/emphysema. High-resolution computed tomographic scans of 26 patients with emphysema (age, >45 years) were reviewed to assess the type and extent of emphysema using the subjective visual scoring. Electrocardiograms were independently reviewed to determine the frontal P vector. The P vector and VSE were compared for statistical correlation. Both P vector and VSE were also directly compared with the forced expiratory volume at 1 second. The VSE and the orientation of the P vector (ÂP) had an overall significant positive correlation (r = +0.68; P = .0001) in all patients, but the correlation was very strong in patients with predominant lower-lobe emphysema (r = +0.88; P = .0004). Forced expiratory volume at 1 second and ÂP had almost a linear inverse correlation in predominant lower-lobe emphysema (r = -0.92; P vertical ÂP and predominant lower-lobe emphysema reflects severe obstructive lung dysfunction. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Influence of Heat Treatment of Nickel-Titanium Rotary Endodontic Instruments on Apical Preparation: A Micro-Computed Tomographic Study.

    Science.gov (United States)

    de Almeida, Bernardo Corrêa; Ormiga, Fabíola; de Araújo, Marcos César Pimenta; Lopes, Ricardo Tadeu; Lima, Inayá Corrêa Barbosa; dos Santos, Bernardo Camargo; Gusman, Heloisa

    2015-12-01

    The aim of this study was to make a 3-dimensional comparison of the canal transportation and changes in apical geometry using micro-computed tomographic imaging after canal preparation with K3 (SybronEndo, Orange, CA) and K3XF (SybronEndo) file systems. Twenty-eight mandibular molars were randomly divided into 2 groups according to the rotary system used in instrumentation: K3 or K3XF. The specimens were scanned by micro-computed tomographic imaging before and after instrumentation. Images before and after instrumentation from each group were compared with regard to canal volume, surface area, and structure model index (SMI) (paired t test, P instrumentation, the canals from each group were compared regarding the changes in volume, surface area, SMI, and canal transportation in the last 4 apical mm (t test, P Instrumentation with the 2 rotary systems significantly changed the canal volume, surface area, and SMI (P instrument types concerning these parameters (P > .05). There were no significant differences between the 2 groups with regard to canal transportation in the last 4 apical mm (P > .05). Both rotary systems showed adequate canal preparations with reduced values of canal transportation. Heat treatment did not influence changes in root canal geometry in the apical region. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  20. The computed tomographic findings of bronchogenic carcinoma presenting as a solitary peripheral pulmonary mass

    International Nuclear Information System (INIS)

    Kim, Hong; Kim, Ok Bae; Woo, Seong Ku; Suh, Soo Jhi; Kim, Sung Soo

    1985-01-01

    It is difficult to distinguish benign from malignant, ulmonary nodule by conventional roentgenologic examination. But CT makes it easier to evaluate adjacent parenchymal invasion, pleural or mediastinal extension, or early metastasis to intra- or extrathoracic lymph node as well as distant organs, although only a solitary peripheral pulmonary nodule is seen on plain radiograph. Authors reviewed CT of 22 cases of histopathologically confirmed primary lung cancer seen as a solitary peripheral pulmonary mass from May 1980 to September 1984 at Dongsan Medical Center, Keimyung University. The results are as follows: 1. The incidence was most common in the 6th decade (36%). Male to female ratio was 10 : 1 and 2 females all had bronchioloalveolar cell carcinoma. 2. The distribution of histologic cell type were as follows: squamous cell carcinoma 40%, adenocarcinoma, small cell carcinoma, bronchioloalveolar cell carcinoma and unclassified carcinoma 14% in each cases, and adenoid cystic carcinoma 4%. 3. The computed tomographic findings were as follows: a) Superior and posterior basal segments of both lower lobes were most frequently involved (68%). b) The mean diameter of the mass was 48 mm, and most common in the range of 30-49 mm in the greatest dimension (46%). c) The mean CT attenuation value was 57 H.U., and most common in the group of 41-70 H. U. (64%). d) Lymph node metastasis was found in 13 (59%) of 22 cases, and the involved nodes were as follows: hilar nodes 10 cases, paratracheal nodes 8 cases, subcarinal nodes 7 cases and extrathoracic nodes 3 cases. In 2 of 3 cases with small cell carcinoma, diffuse multiple lymph nodes were involved. e) Distant metastasis was seen relatively early in 3 cases: cerebral metastasis in 1 cases of squamous cell carcinoma, right adrenal metastasis without intrathoracic lymph node metastasis or invasion of adjacent structure in 1 case of bronchioloalveolar cell carcinoma, and liver and bone metastasis in 1 case of unclassified

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. High spatial resolution CT image reconstruction using parallel computing

    International Nuclear Information System (INIS)

    Yin Yin; Liu Li; Sun Gongxing

    2003-01-01

    Using the PC cluster system with 16 dual CPU nodes, we accelerate the FBP and OR-OSEM reconstruction of high spatial resolution image (2048 x 2048). Based on the number of projections, we rewrite the reconstruction algorithms into parallel format and dispatch the tasks to each CPU. By parallel computing, the speedup factor is roughly equal to the number of CPUs, which can be up to about 25 times when 25 CPUs used. This technique is very suitable for real-time high spatial resolution CT image reconstruction. (authors)

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

    Science.gov (United States)

    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.

  4. Thanatophoric dysplasia: case report of an autopsy complemented by postmortem computed tomographic study

    Directory of Open Access Journals (Sweden)

    Éber Emanuel Mayoral

    2014-06-01

    Full Text Available Thanatophoric dysplasia (TD is one of the most common lethal skeletal dysplasias, which was first designated as thanatophoric dwarfism and described in 1967. The authors report a case of a Caucasian girl with TD, born to a 31-year-old woman without comorbidities. The newborn presented respiratory distress immediately after delivery, progressing to death in less than 2 hours. An autopsy was carried out after postmortem tomographic examination. The autopsy findings depicted extensive malformations of the skeletal system and the brain. The aim of this report is to discuss the pathogenesis and correlate the morphologic features of TD that were disclosed at the tomography and the autopsy.

  5. Incomplete projection reconstruction of computed tomography based on the modified discrete algebraic reconstruction technique

    Science.gov (United States)

    Yang, Fuqiang; Zhang, Dinghua; Huang, Kuidong; Gao, Zongzhao; Yang, YaFei

    2018-02-01

    Based on the discrete algebraic reconstruction technique (DART), this study aims to address and test a new improved algorithm applied to incomplete projection data to generate a high quality reconstruction image by reducing the artifacts and noise in computed tomography. For the incomplete projections, an augmented Lagrangian based on compressed sensing is first used in the initial reconstruction for segmentation of the DART to get higher contrast graphics for boundary and non-boundary pixels. Then, the block matching 3D filtering operator was used to suppress the noise and to improve the gray distribution of the reconstructed image. Finally, simulation studies on the polychromatic spectrum were performed to test the performance of the new algorithm. Study results show a significant improvement in the signal-to-noise ratios (SNRs) and average gradients (AGs) of the images reconstructed from incomplete data. The SNRs and AGs of the new images reconstructed by DART-ALBM were on average 30%-40% and 10% higher than the images reconstructed by DART algorithms. Since the improved DART-ALBM algorithm has a better robustness to limited-view reconstruction, which not only makes the edge of the image clear but also makes the gray distribution of non-boundary pixels better, it has the potential to improve image quality from incomplete projections or sparse projections.

  6. The early development of medial coronoid disease in growing Labrador retrivers: Radographic, computed tomographic, necropsy and micro-computed tomographic findings

    NARCIS (Netherlands)

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

    2013-01-01

    Abstract Medial coronoid disease (MCD) encompasses lesions of the entire medial coronoid process (MCP), both of the articular cartilage and the subchondral bone. To detect the earliest signs of MCD, radiography and computed tomography were used to monitor the development of MCD in 14 Labrador

  7. Utility of cervical spinal and abdominal computed tomography in diagnosing occult pneumothorax in patients with blunt trauma: Computed tomographic imaging protocol matters.

    Science.gov (United States)

    Akoglu, Haldun; Akoglu, Ebru Unal; Evman, Serdar; Akoglu, Tayfun; Denizbasi, Arzu; Guneysel, Ozlem; Onur, Ozge; Onur, Ender

    2012-10-01

    Small pneumothoraces (PXs), which are not initially recognized with a chest x-ray film and diagnosed by a thoracic computed tomography (CT), are described as occult PX (OCPX). The objective of this study was to evaluate cervival spine (C-spine) and abdominal CT (ACT) for diagnosing OCPX and overt PX (OVPX). All patients with blunt trauma who presented consecutively to the emergency department during a 26-months period were included. Among all the chest CTs (CCTs) (6,155 patients) conducted during that period, 254 scans were confirmed to have a true PX. The findings in their C-spine CT and ACT were compared with the findings in CCTs. Among these patients, 254 had a diagnosis of PX confirmed with CCT. OCPXs were identified on the chest computed tomographic scan of 128 patients (70.3%), whereas OVPXs were evident in 54 patients (29.7%). Computed tomographic imaging of the C-spine was performed in 74% of patients with OCPX and 66.7% of patients with OVPX trauma. Only 45 (35.2%) cases of OCPX and 42 (77.8%) cases of OVPX were detected by C-spine CT. ACT was performed in almost all patients, and 121 (95.3%) of 127 of these correctly identified an existing OCPX. Sensitivity of C-spine CT and ACT was 35.1% and 96.5%, respectively; specificity was 100% and 100%, respectively. Almost all OCPXs, regardless of intrathoracic location, could be detected by ACT or by combining C-spine and abdominal computed tomographic screening for patients. If the junction of the first and second vertebra is used as the caudad extent, C-spine CT does not have sufficient power to diagnose more than a third of the cases. Diagnostic study, level III.

  8. [Computer-assisted temporomandibular joint reconstruction.

    Science.gov (United States)

    Zwetyenga, N; Mommers, X-A; Cheynet, F

    2013-08-02

    Prosthetic replacement of TMJ is gradually becoming a common procedure because of good functional and aesthetic results and low morbidity. Prosthetic models available can be standard or custom-made. Custom-made prosthesis are usually reserved for complex cases, but we think that computer assistance for custom-made prosthesis should be indicated for each case because it gives a greater implant stability and fewer complications. Computer assistance will further enlarge TMJ prosthesis replacement indications. Copyright © 2013. Published by Elsevier Masson SAS.

  9. Suppression of intensity transition artifacts in statistical x-ray computer tomography reconstruction through Radon inversion initialization

    International Nuclear Information System (INIS)

    Zbijewski, Wojciech; Beekman, Freek J.

    2004-01-01

    Statistical reconstruction (SR) methods provide a general and flexible framework for obtaining tomographic images from projections. For several applications SR has been shown to outperform analytical algorithms in terms of resolution-noise trade-off achieved in the reconstructions. A disadvantage of SR is the long computational time required to obtain the reconstructions, in particular when large data sets characteristic for x-ray computer tomography (CT) are involved. As was shown recently, by combining statistical methods with block iterative acceleration schemes [e.g., like in the ordered subsets convex (OSC) algorithm], the reconstruction time for x-ray CT applications can be reduced by about two orders of magnitude. There are, however, some factors lengthening the reconstruction process that hamper both accelerated and standard statistical algorithms to similar degree. In this simulation study based on monoenergetic and scatter-free projection data, we demonstrate that one of these factors is the extremely high number of iterations needed to remove artifacts that can appear around high-contrast structures. We also show (using the OSC method) that these artifacts can be adequately suppressed if statistical reconstruction is initialized with images generated by means of Radon inversion algorithms like filtered back projection (FBP). This allows the reconstruction time to be shortened by even as much as one order of magnitude. Although the initialization of the statistical algorithm with FBP image introduces some additional noise into the first iteration of OSC reconstruction, the resolution-noise trade-off and the contrast-to-noise ratio of final images are not markedly compromised

  10. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Science.gov (United States)

    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

  12. Tomographic reconstruction of melanin structures of optical coherence tomography via the finite-difference time-domain simulation

    Science.gov (United States)

    Huang, Shi-Hao; Wang, Shiang-Jiu; Tseng, Snow H.

    2015-03-01

    Optical coherence tomography (OCT) provides high resolution, cross-sectional image of internal microstructure of biological tissue. We use the Finite-Difference Time-Domain method (FDTD) to analyze the data acquired by OCT, which can help us reconstruct the refractive index of the biological tissue. We calculate the refractive index tomography and try to match the simulation with the data acquired by OCT. Specifically, we try to reconstruct the structure of melanin, which has complex refractive indices and is the key component of human pigment system. The results indicate that better reconstruction can be achieved for homogenous sample, whereas the reconstruction is degraded for samples with fine structure or with complex interface. Simulation reconstruction shows structures of the Melanin that may be useful for biomedical optics applications.

  13. Design and performance of a new positron computed tomograph (P.C.T.) using the time-of-flight (T.O.F.) information

    International Nuclear Information System (INIS)

    Laval, M.; Allemand, R.; Bouvier, A.

    1982-09-01

    A new tomograph for positron imaging using the time of flight measurement is described. Fast CsF crystals are used in this first prototype. Compared to the classical reconstruction method, the results of adding this information is a substantial increase of sensitivity, a reduced random coincidence count rate, and slight decrease of a scatter contribution in the images. Further improvements in the T.O.F. accuracy can be expected in using faster crystals

  14. Tomographic PIV: principles and practice

    International Nuclear Information System (INIS)

    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. (topical review)

  15. Precision of quantum tomographic detection of radiation

    Energy Technology Data Exchange (ETDEWEB)

    D' Ariano, G.M. (Dipartimento di Fisica ' ' Alessandro Volta' ' , Via A. Bassi 6, I-27100, Pavia (Italy) Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Via A. Bassi 6, I-27100, Pavia (Italy)); Macchiavello, Chiara (Dipartimento di Fisica ' ' Alessandro Volta' ' , Via A. Bassi 6, I-27100, Pavia (Italy)); Paris, M.G.A. (Dipartimento di Fisica ' ' Alessandro Volta' ' , Via A. Bassi 6, I-27100, Pavia (Italy))

    1994-11-21

    Homodyne tomography provides an experimental technique for reconstructing the density matrix of the radiation field. Here we analyze the tomographic precision in recovering observables like the photon number, the quadrature, and the phase. We show that tomographic reconstruction, despite providing a complete characterization of the state of the field, is generally much less efficient than conventional detection techniques. ((orig.))

  16. Precision of quantum tomographic detection of radiation

    International Nuclear Information System (INIS)

    D'Ariano, G.M.; Macchiavello, Chiara; Paris, M.G.A.

    1994-01-01

    Homodyne tomography provides an experimental technique for reconstructing the density matrix of the radiation field. Here we analyze the tomographic precision in recovering observables like the photon number, the quadrature, and the phase. We show that tomographic reconstruction, despite providing a complete characterization of the state of the field, is generally much less efficient than conventional detection techniques. ((orig.))

  17. Computed tomographic simulation of craniospinal fields in pediatric patients: improved treatment accuracy and patient comfort.

    Science.gov (United States)

    Mah, K; Danjoux, C E; Manship, S; Makhani, N; Cardoso, M; Sixel, K E

    1998-07-15

    To reduce the time required for planning and simulating craniospinal fields through the use of a computed tomography (CT) simulator and virtual simulation, and to improve the accuracy of field and shielding placement. A CT simulation planning technique was developed. Localization of critical anatomic features such as the eyes, cribriform plate region, and caudal extent of the thecal sac are enhanced by this technique. Over a 2-month period, nine consecutive pediatric patients were simulated and planned for craniospinal irradiation. Four patients underwent both conventional simulation and CT simulation. Five were planned using CT simulation only. The accuracy of CT simulation was assessed by comparing digitally reconstructed radiographs (DRRs) to portal films for all patients and to conventional simulation films as well in the first four patients. Time spent by patients in the CT simulation suite was 20 min on average and 40 min maximally for those who were noncompliant. Image acquisition time was absence of the patient, virtual simulation of all fields took 20 min. The DRRs were in agreement with portal and/or simulation films to within 5 mm in five of the eight cases. Discrepancies of > or =5 mm in the positioning of the inferior border of the cranial fields in the first three patients were due to a systematic error in CT scan acquisition and marker contouring which was corrected by modifying the technique after the fourth patient. In one patient, the facial shield had to be moved 0.75 cm inferiorly owing to an error in shield construction. Our analysis showed that CT simulation of craniospinal fields was accurate. It resulted in a significant reduction in the time the patient must be immobilized during the planning process. This technique can improve accuracy in field placement and shielding by using three-dimensional CT-aided localization of critical and target structures. Overall, it has improved staff efficiency and resource utilization.

  18. Computed tomographic simulation of craniospinal fields in pediatric patients: improved treatment accuracy and patient comfort

    International Nuclear Information System (INIS)

    Mah, Katherine; Danjoux, Cyril E.; Manship, Sharan; Makhani, Nadiya; Cardoso, Marlene; Sixel, Katharina E.

    1998-01-01

    Purpose: To reduce the time required for planning and simulating craniospinal fields through the use of a computed tomography (CT) simulator and virtual simulation, and to improve the accuracy of field and shielding placement. Methods and Materials: A CT simulation planning technique was developed. Localization of critical anatomic features such as the eyes, cribriform plate region, and caudal extent of the thecal sac are enhanced by this technique. Over a 2-month period, nine consecutive pediatric patients were simulated and planned for craniospinal irradiation. Four patients underwent both conventional simulation and CT simulation. Five were planned using CT simulation only. The accuracy of CT simulation was assessed by comparing digitally reconstructed radiographs (DRRs) to portal films for all patients and to conventional simulation films as well in the first four patients. Results: Time spent by patients in the CT simulation suite was 20 min on average and 40 min maximally for those who were noncompliant. Image acquisition time was <10 min in all cases. In the absence of the patient, virtual simulation of all fields took 20 min. The DRRs were in agreement with portal and/or simulation films to within 5 mm in five of the eight cases. Discrepancies of ≥5 mm in the positioning of the inferior border of the cranial fields in the first three patients were due to a systematic error in CT scan acquisition and marker contouring which was corrected by modifying the technique after the fourth patient. In one patient, the facial shield had to be moved 0.75 cm inferiorly owing to an error in shield construction. Conclusions: Our analysis showed that CT simulation of craniospinal fields was accurate. It resulted in a significant reduction in the time the patient must be immobilized during the planning process. This technique can improve accuracy in field placement and shielding by using three-dimensional CT-aided localization of critical and target structures. Overall

  19. Coronary Computed Tomographic Angiography at Low Concentration of Contrast Agent and Low Tube Voltage in Patients with Obesity:: A Feasibility Study.

    Science.gov (United States)

    Pan, Yu-Ning; Li, Ai-Jing; Chen, Xiao-Min; Wang, Jian; Ren, Da-Wei; Huang, Qiu-Li

    2016-04-01

    Using lower tube voltage can reduce the exposure to radiation and the dose of contrast agent. However, lower tube voltage is often linked to more noise and poor image quality, which create a need for more effective technology to resolve this problem. To explore the feasibility of coronary computed tomographic angiography (CCTA) in patients with obesity at low tube voltage (100 kV) and low contrast agent concentration (270 mg/mL) using iterative reconstruction. A total of 48 patients with body mass index greater than 30 kg/m(2) were included and randomly divided into two groups. Group A received a traditional protocol (iopromide 370 mg/mL + 120 kV); group B received a protocol with low tube voltage (100 kV), low contrast agent concentration (270 mg/mL), and iterative reconstruction. The effective dose (ED), average attenuation values, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), the figure of merit (FOM), image quality scores, and the total iodine intake were compared. No significant differences in average CT attenuations, SNR, CNR, and subjective scores were noticed between the two groups (P > 0.05), whereas the FOM of group B was significantly higher than that of group A. Effective radiation dose, total iodine, and iodine injection rate in group B were lower than those of group A (P contrast agent with low iodine concentration and low-dose CCTA were feasible. Substantial reduction in radiation dose and the iodine intake could be achieved without compromising the image quality. Copyright © 2016 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  20. Applications of Computer Technology in Complex Craniofacial Reconstruction

    Directory of Open Access Journals (Sweden)

    Kristopher M. Day, MD

    2018-03-01

    Conclusion:. Modern 3D technology allows the surgeon to better analyze complex craniofacial deformities, precisely plan surgical correction with computer simulation of results, customize osteotomies, plan distractions, and print 3DPCI, as needed. The use of advanced 3D computer technology can be applied safely and potentially improve aesthetic and functional outcomes after complex craniofacial reconstruction. These techniques warrant further study and may be reproducible in various centers of care.

  1. Preexisting Dentinal Microcracks in Nonendodontically Treated Teeth: An Ex Vivo Micro-computed Tomographic Analysis.

    Science.gov (United States)

    PradeepKumar, Angambakkam Rajasekaran; Shemesh, Hagay; Chang, Jeffrey Wen-Wei; Bhowmik, Ahendita; Sibi, Swamy; Gopikrishna, Velayutham; Lakshmi-Narayanan, Lakshmikanthanbharathi; Kishen, Anil

    2017-06-01

    This study evaluated the prevalence, location, and pattern of preexisting dentinal microcracks in roots of extracted teeth without endodontic treatment in patients from 2 age groups using micro-computed tomographic imaging. Six hundred thirty-three nonendodontically treated teeth extracted using an atraumatic procedure because of reasons unrelated to this study were collected and divided based on the patient age. Teeth were scanned with micro-computed tomographic imaging (resolution of 26.7 μm) to examine the presence of preexisting dentinal microcracks in roots. The characteristic features of preexisting dentinal microcracks determined were location, extent, length, and coronoapical distribution. Chi-square bivariate analysis was performed to assess the association between various parameters. Forty-five of 633 nonendodontically treated teeth exhibited preexisting microcracks in roots with a prevalence of 7.1%. The prevalence of preexisting microcracks was found to be 8.3% in older patients (40-70 years) compared with 3.7% in younger patients (20-39 years) (P < .050). A significant association was found between the preexisting microcracks in mandibular teeth (10.3%) when compared with maxillary teeth (2.9%) (P < .001). All preexisting microcracks were located mesiodistally; 66% occurred in the cervical and middle thirds of root. Only 33% of the preexisting microcracks were complete in nature, showing canal involvement. Complete dentinal microcracks exhibited a mean length of 6.9 mm, whereas incomplete cracks had a mean length of 3.75 mm (P < .001). Preexisting dentinal microcracks in roots of nonendodontically treated teeth occurred more often in older patients (40-70 years) in the mesiodistal direction. They were predominantly found in the cervical and middle thirds of root and were more likely to be incomplete in nature. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. Computed tomographic features of apical infection of equine maxillary cheek teeth: a retrospective study of 49 horses.

    Science.gov (United States)

    Bühler, M; Fürst, A; Lewis, F I; Kummer, M; Ohlerth, S

    2014-07-01

    Computed tomographic (CT) studies evaluating the relevance of individual CT features of apical infection in maxillary cheek teeth are lacking. To study the prevalence and relationship of single CT features in horses with and without clinical evidence of apical infection in maxillary cheek teeth. Retrospective case-control study. Multislice CT scans of the head of 49 horses were evaluated retrospectively. Changes of the infundibulum, pulp, root, lamina dura, periodontal space and alveolar bone in maxillary cheek teeth were recorded. Single CT changes were much more prevalent in the 28 horses with clinical signs. However, infundibular changes and a nondetectable lamina dura were also common in the 21 horses without clinical evidence of apical infection. Computed tomographic abnormalities of the pulp, root, periapical bone and periodontal space and the presence of a tooth fracture were significantly related. Infundibular changes were not associated with other CT signs of apical infection. Although nondetectable lamina dura was the most frequent CT change in all teeth in both studied groups, it was most commonly a solitary feature in otherwise normal teeth. Apical infections, defined as ≥3 CT changes, occurred mainly in the 108/208, 109/209 and 110/210 (Triadan numbers) and were found only in horses with clinical evidence of apical infection, except in one horse without clinical signs that had one affected root. Combined CT changes of the pulp, root, lamina dura, periapical bone and periodontal space and the presence of a tooth fracture appear to be reliable features to diagnose apical infection in maxillary cheek teeth. As a solitary feature, a nondetectable lamina dura should be interpreted cautiously and may even be considered normal due to its minor thickness and/or too low resolution of the imaging modality. © 2013 EVJ Ltd.

  3. Transient ischemic attacks with and without a relevant infarct on computed tomographic scans cannot be distinguished clinically. Dutch Transient Ischemic Attack Study Group

    NARCIS (Netherlands)

    Koudstaal, P. J.; van Gijn, J.; Lodder, J.; Frenken, W. G.; Vermeulen, M.; Franke, C. L.; Hijdra, A.; Bulens, C.

    1991-01-01

    We prospectively studied clinical and computed tomographic (CT) scan findings in 79 patients with a transient ischemic attack (TIA) and a relevant cerebral infarction on CT, also known as cerebral infarction with transient signs (CITS). We compared the results with those of 527 concurrent patients

  4. Hepatic Rupture Caused by Hemolysis, Elevated Liver Enzyme, and Low Platelet Count Syndrome: A Case Report with Computed Tomographic and Conventional Angiographic Findings

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Algorithm for three dimension reconstruction of magnetic resonance tomographs and X-ray images based on Fast Fourier Transform

    International Nuclear Information System (INIS)

    Bueno, Josiane M.; Traina, Agma Juci M.; Cruvinel, Paulo E.

    1995-01-01

    This work presents an algorithm for three-dimensional digital image reconstruction. Such algorithms based on the combination of both a Fast Fourier Transform method with Hamming Window and the use of a tri-linear interpolation function. The algorithm allows not only the generation of three-dimensional spatial spin distribution maps for Magnetic Resonance Tomography data but also X and Y-rays linear attenuation coefficient maps for CT scanners. Results demonstrates the usefulness of the algorithm in three-dimensional image reconstruction by doing first two-dimensional reconstruction and rather after interpolation. The algorithm was developed in C++ language, and there are two available versions: one under the DOS environment, and the other under the UNIX/Sun environment. (author)

  6. Parallel computing for event reconstruction in high-energy physics

    International Nuclear Information System (INIS)

    Wolbers, S.

    1993-01-01

    Parallel computing has been recognized as a solution to large computing problems. In High Energy Physics offline event reconstruction of detector data is a very large computing problem that has been solved with parallel computing techniques. A review of the parallel programming package CPS (Cooperative Processes Software) developed and used at Fermilab for offline reconstruction of Terabytes of data requiring the delivery of hundreds of Vax-Years per experiment is given. The Fermilab UNIX farms, consisting of 180 Silicon Graphics workstations and 144 IBM RS6000 workstations, are used to provide the computing power for the experiments. Fermilab has had a long history of providing production parallel computing starting with the ACP (Advanced Computer Project) Farms in 1986. The Fermilab UNIX Farms have been in production for over 2 years with 24 hour/day service to experimental user groups. Additional tools for management, control and monitoring these large systems will be described. Possible future directions for parallel computing in High Energy Physics will be given

  7. Multiplanar reconstruction computed tomography for diagnosis of scaphoid waist fracture union: a prospective cohort analysis of accuracy and precision

    Energy Technology Data Exchange (ETDEWEB)

    Hannemann, P.F.W.; Brouwers, L.; Gottgens, K.W.A.; Poeze, M.; Brink, P.R.G. [Maastricht University Medical Centre, Department of Surgery and Traumasurgery, PO Box 5800, Maastricht (Netherlands); Zee, D. van der; Stadler, A.; Weijers, R. [Maastricht University Medical Centre, Department of radiology, PO Box 5800, Maastricht (Netherlands)

    2013-10-15

    To examine reliability and validity concerning union of scaphoid fractures determined by multiplanar reconstruction computed tomography randomized at 6, 12, and 24 weeks after injury. We used Fleiss' kappa to measure the opinions of three observers reviewing 44 sets of computed tomographic scans of 44 conservatively treated scaphoid waist fractures. We calculated kappa for the extent of consolidation (0-24 %, 25-49 %, 50-74 %, or 75-100 %) on the transverse, sagittal and coronal views. We also calculated kappa for no union, partial union, and union, and grouped the results for 6, 12, and 24 weeks after injury. As the reference standard for union, CT scans were performed at a minimum of 6 months after injury to determine validity. Overall inter-observer agreement was found to be moderate ({kappa} = 0.576). No union ({kappa} = 0.791), partial union ({kappa} = 0.502), and union ({kappa} = 0.683) showed substantial, moderate, and substantial agreement, respectively. The average sensitivity of multiplanar reconstruction CT for diagnosing union of scaphoid waist fractures was 73 %. The average specificity was 80 %. Our results suggest that multiplanar reconstruction computed tomography is a reliable and accurate method for diagnosing union or nonunion of scaphoid fractures. However, inter-observer agreement was lower with respect to partial union. (orig.)

  8. Multiplanar reconstruction computed tomography for diagnosis of scaphoid waist fracture union: a prospective cohort analysis of accuracy and precision

    International Nuclear Information System (INIS)

    Hannemann, P.F.W.; Brouwers, L.; Gottgens, K.W.A.; Poeze, M.; Brink, P.R.G.; Zee, D. van der; Stadler, A.; Weijers, R.

    2013-01-01

    To examine reliability and validity concerning union of scaphoid fractures determined by multiplanar reconstruction computed tomography randomized at 6, 12, and 24 weeks after injury. We used Fleiss' kappa to measure the opinions of three observers reviewing 44 sets of computed tomographic scans of 44 conservatively treated scaphoid waist fractures. We calculated kappa for the extent of consolidation (0-24 %, 25-49 %, 50-74 %, or 75-100 %) on the transverse, sagittal and coronal views. We also calculated kappa for no union, partial union, and union, and grouped the results for 6, 12, and 24 weeks after injury. As the reference standard for union, CT scans were performed at a minimum of 6 months after injury to determine validity. Overall inter-observer agreement was found to be moderate (κ = 0.576). No union (κ = 0.791), partial union (κ = 0.502), and union (κ = 0.683) showed substantial, moderate, and substantial agreement, respectively. The average sensitivity of multiplanar reconstruction CT for diagnosing union of scaphoid waist fractures was 73 %. The average specificity was 80 %. Our results suggest that multiplanar reconstruction computed tomography is a reliable and accurate method for diagnosing union or nonunion of scaphoid fractures. However, inter-observer agreement was lower with respect to partial union. (orig.)

  9. Real-time digital filtering, event triggering, and tomographic reconstruction of JET soft x-ray data (abstract)

    Science.gov (United States)

    Edwards, A. W.; Blackler, K.; Gill, R. D.; van der Goot, E.; Holm, J.

    1990-10-01

    Based upon the experience gained with the present soft x-ray data acquisition system, new techniques are being developed which make extensive use of digital signal processors (DSPs). Digital filters make 13 further frequencies available in real time from the input sampling frequency of 200 kHz. In parallel, various algorithms running on further DSPs generate triggers in response to a range of events in the plasma. The sawtooth crash can be detected, for example, with a delay of only 50 μs from the onset of the collapse. The trigger processor interacts with the digital filter boards to ensure data of the appropriate frequency is recorded throughout a plasma discharge. An independent link is used to pass 780 and 24 Hz filtered data to a network of transputers. A full tomographic inversion and display of the 24 Hz data is carried out in real time using this 15 transputer array. The 780 Hz data are stored for immediate detailed playback following the pulse. Such a system could considerably improve the quality of present plasma diagnostic data which is, in general, sampled at one fixed frequency throughout a discharge. Further, it should provide valuable information towards designing diagnostic data acquisition systems for future long pulse operation machines when a high degree of real-time processing will be required, while retaining the ability to detect, record, and analyze events of interest within such long plasma discharges.

  10. The modeling of quadratic B-splines surfaces for the tomographic reconstruction in the FCC- type-riser

    International Nuclear Information System (INIS)

    Vasconcelos, Geovane Vitor; Dantas, Carlos Costa; Melo, Silvio de Barros; Pires, Renan Ferraz

    2009-01-01

    The 3D tomography reconstruction has been a profitable alternative in the analysis of the FCC-type- riser (Fluid Catalytic Cracking), for appropriately keeping track of the sectional catalyst concentration distribution in the process of oil refining. The method of tomography reconstruction proposed by M. Azzi and colleagues (1991) uses a relatively small amount of trajectories (from 3 to 5) and projections (from 5 to 7) of gamma rays, a desirable feature in the industrial process tomography. Compared to more popular methods, such as the FBP (Filtered Back Projection), which demands a much higher amount of gamma rays projections, the method by Azzi et al. is more appropriate for the industrial process, where the physical limitations and the cost of the process require more economical arrangements. The use of few projections and trajectories facilitates the diagnosis in the flow dynamical process. This article proposes an improvement in the basis functions introduced by Azzi et al., through the use of quadratic B-splines functions. The use of B-splines functions makes possible a smoother surface reconstruction of the density distribution, since the functions are continuous and smooth. This work describes how the modeling can be done. (author)

  11. A fast multi-resolution approach to tomographic PIV

    Science.gov (United States)

    Discetti, Stefano; Astarita, Tommaso

    2012-03-01

    Tomographic particle image velocimetry (Tomo-PIV) is a recently developed three-component, three-dimensional anemometric non-intrusive measurement technique, based on an optical tomographic reconstruction applied to simultaneously recorded images of the distribution of light intensity scattered by seeding particles immersed into the flow. Nowadays, the reconstruction process is carried out mainly by iterative algebraic reconstruction techniques, well suited to handle the problem of limited number of views, but computationally intensive and memory demanding. The adoption of the multiplicative algebraic reconstruction technique (MART) has become more and more accepted. In the present work, a novel multi-resolution approach is proposed, relying on the adoption of a coarser grid in the first step of the reconstruction to obtain a fast estimation of a reliable and accurate first guess. A performance assessment, carried out on three-dimensional computer-generated distributions of particles, shows a substantial acceleration of the reconstruction process for all the tested seeding densities with respect to the standard method based on 5 MART iterations; a relevant reduction in the memory storage is also achieved. Furthermore, a slight accuracy improvement is noticed. A modified version, improved by a multiplicative line of sight estimation of the first guess on the compressed configuration, is also tested, exhibiting a further remarkable decrease in both memory storage and computational effort, mostly at the lowest tested seeding densities, while retaining the same performances in terms of accuracy.

  12. Detection of common bile duct stones: comparison between endoscopic ultrasonography, magnetic resonance cholangiography, and helical-computed-tomographic cholangiography

    International Nuclear Information System (INIS)

    Kondo, Shintaro; Isayama, Hiroyuki; Akahane, Masaaki; Toda, Nobuo; Sasahira, Naoki; Nakai, Yosuke; Yamamoto, Natsuyo; Hirano, Kenji; Komatsu, Yutaka; Tada, Minoru; Yoshida, Haruhiko; Kawabe, Takao; Ohtomo, Kuni; Omata, Masao

    2005-01-01

    Objectives: New modalities, namely, endoscopic ultrasonography (EUS), magnetic resonance cholangiopancreatography (MRCP), and helical computed-tomographic cholangiography (HCT-C), have been introduced recently for the detection of common bile duct (CBD) stones and shown improved detectability compared to conventional ultrasound or computed tomography. We conducted this study to compare the diagnostic ability of EUS, MRCP, and HCT-C in patients with suspected choledocholithiasis. Methods: Twenty-eight patients clinically suspected of having CBD stones were enrolled, excluding those with cholangitis or a definite history of choledocholithiasis. Each patient underwent EUS, MRCP, and HCT-C prior to endoscopic retrograde cholangio-pancreatography (ERCP), the result of which served as the diagnostic gold standard. Results: CBD stones were detected in 24 (86%) of 28 patients by ERCP/IDUS. The sensitivity of EUS, MRCP, and HCT-C was 100%, 88%, and 88%, respectively. False negative cases for MRCP and HCT-C had a CBD stone smaller than 5 mm in diameter. No serious complications occurred while one patient complained of itching in the eyelids after the infusion of contrast agent on HCT-C. Conclusions: When examination can be scheduled, MRCP or HCT-C will be the first choice because they were less invasive than EUS. MRCP and HCT-C had similar detectability but the former may be preferable considering the possibility of allergic reaction in the latter. When MRCP is negative, EUS is recommended to check for small CBD stones

  13. Development of computed tomography system and image reconstruction algorithm

    International Nuclear Information System (INIS)

    Khairiah Yazid; Mohd Ashhar Khalid; Azaman Ahmad; Khairul Anuar Mohd Salleh; Ab Razak Hamzah

    2006-01-01

    Computed tomography is one of the most advanced and powerful nondestructive inspection techniques, which is currently used in many different industries. In several CT systems, detection has been by combination of an X-ray image intensifier and charge -coupled device (CCD) camera or by using line array detector. The recent development of X-ray flat panel detector has made fast CT imaging feasible and practical. Therefore this paper explained the arrangement of a new detection system which is using the existing high resolution (127 μm pixel size) flat panel detector in MINT and the image reconstruction technique developed. The aim of the project is to develop a prototype flat panel detector based CT imaging system for NDE. The prototype consisted of an X-ray tube, a flat panel detector system, a rotation table and a computer system to control the sample motion and image acquisition. Hence this project is divided to two major tasks, firstly to develop image reconstruction algorithm and secondly to integrate X-ray imaging components into one CT system. The image reconstruction algorithm using filtered back-projection method is developed and compared to other techniques. The MATLAB program is the tools used for the simulations and computations for this project. (Author)

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

    Science.gov (United States)

    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.

  15. Computed tomographic pulmonary angiography in the assessment of severity of chronic thromboembolic pulmonary hypertension and right ventricular dysfunction

    International Nuclear Information System (INIS)

    Liu Min; Ma Zhanhong; Guo Xiaojuan; Zhang Hongxia; Yang Yuanhua; WangChen

    2011-01-01

    Purpose: The aim was to investigate the role of computed tomographic pulmonary angiography (CTPA) in the assessment of severity and right ventricular function in chronic thromboembolic pulmonary hypertension (CTEPH). Materials and methods: Clinical and radiological data of 56 patients with CTEPH January 2006–October 2009 were retrospectively reviewed in the present study. All patients received CTPA with a 64-row CT using the retrospective ECG-Gated mode before digital subtraction pulmonary angiography and right-heart catheterization. CTPA findings including Right Ventricular diameter (RVd) and left ventricular diameter (LVd) were measured at the end diastole. CT Pulmonary Artery Obstruction Indexes including Qanadli Index and Mastora Index were used in the assessment of severity of pulmonary arterial obstruction. Hemodynamic parameters and pulmonary hypertension classification were evaluated by right-heart catheterization in all patients. Right ventricular function was measured with echocardiography in 49 patients. Results: Qanadli Index and Mastora Index respectively were (37.93 ± 14.74)% and (30.92 ± 16.91)%, which showed a significant difference (Z = −5.983, P = 0.000) and a good correlation (r = 0.881, P = 0.000). Neither Qanadli nor Mastora Index correlated with pulmonary hypertension classification (r = −0.009, P = 0.920) or New York Heart Association heart function classification (r = −0.031, P = 0.756). Neither Qanadli nor Mastora Index correlated with any echocardiographic right ventricular parameters (P > 0.05), while RVd/LVd by CTPA correlated with echocardiographic right ventricular functional parameters (P 2 . CTPA findings correlated with hemodynamic variables. Backward linear regression analysis revealed that the RVd/LVd, Right Ventricular Anterior Wall Thickness (RVAWT), Main Pulmonary Artery trunk diameter (MPAd) were shown to be independently associated with mean Pulmonary Artery Pressure (mPAP) levels (model: r 2 = 0.351, P = 0.025; RVd

  16. Differential diagnosis of solitary pulmonary inflammatory lesions and peripheral lung cancers with contrast-enhanced computed tomograph

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Zhi-gang; Sheng, Bo; Liu, Meng-qi; Lv, Fa-jin; Li, Qi; Ouyang, Yu, E-mail: cyscitg@163.com [Hospital of Chongqing Medical University, Department of Radiology, Chongqing (China)

    2016-10-15

    Objectives: To clarify differences between solitary pulmonary inflammatory lesions and peripheral lung cancers with contrast-enhanced computed tomography. Methods: In total, 64 and 132 patients with solitary pulmonary inflammatory masses/nodules and peripheral lung cancers, respectively, were enrolled in this study. Their computed tomographic findings were summarized and compared retrospectively. Results: Compared with the peripheral lung cancers, the inflammatory lesions were located closer to the pleura (p<0.0001). The majority of the inflammatory lesions were patchy and oval-shaped (82.8%), whereas most of the tumors were lobulated (82.6%). Almost all the inflammatory cases were unclear (93.8%), whereas most of the tumors had speculated margins (72.7%). Computed tomography values were significantly higher for the inflammatory lesions than for the cancers (p<0.0001). More than half of the inflammatory lesions had defined necrosis (59.3%). Furthermore, 49.2% of the cancers enhanced inhomogeneously, but only 24.6% had ill-defined necrosis or cavities. The peripheral zones of 98.4% of the inflammatory lesions and 72.7% of the tumors were unclear, with peripheral scattered patches (92.2%) and beam-shaped opacity (66.7%) being the most common findings, respectively. Adjacent pleural thickening was more frequent for the inflammatory lesions than the cancers (95.3% vs. 21.1%, p<0.0001), whereas pleural indentation was found in 67.4% of the subjects with cancer. In addition, hilar (p=0.034) and mediastinal (p=0.003) lymphadenopathy were more commonly detected in the cancers than in the inflammatory cases. Conclusions: Contrast-enhanced computed tomography findings for pulmonary inflammatory lesions and peripheral lung cancers were significantly different in many aspects. Developing a comprehensive understanding of these differences is helpful for directing their management. (author)

  17. Higgs Reconstructed at CERN’s Computer Centre

    CERN Multimedia

    2012-01-01

    Thanks to the enormous computing capacity of the CERN Computer Centre, which hosts about 12,000 servers with 16,000 CPUs (i.e. 64,000 computing cores) and 64,000 hard-disks distributed over 1,100 racks and storing another 22 PB (PetaByte, i.e. 22 million billion bytes) of LHC data during 2011, CERN computing specialists have managed for the first time to reconstruct the “Higgs” (see photo below in which the newly installed racks are highlighted).   In fact, as clear physics evidence of the Higgs is still pending and expected to be established in 2012, the CERN Computer Centre operators have instead rearranged their computer racks in the Computer Centre (Building 513) to spell the word “Higgs”. Bruce Peppa, group leader of the IT/CC group who manages the Computer Centre, said “As many people have noticed, for a few months serious construction work has been going on in the annex to the CERN Computer Centre. With the installation of more servers ...

  18. Ultrasound and computed tomographic demonstration of portal vein thrombosis in hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Pauls, C H

    1981-07-15

    Two cases of multinodular hepatocellular carcinoma (HCC) in which ultrasound and computed tomography (CT) revealed portal vein thrombosis are presented. The diagnostic value of determining the presence of portal vein thrombosis in patients with suspected HCC is discussed.

  19. Computed tomographic demonstration of a spontaneous subcapsular hematoma due to a small renal cell carcinoma

    International Nuclear Information System (INIS)

    Hilton, S.; Bosniak, M.A.; Megibow, A.J.; Ambos, M.A.

    1981-01-01

    Computed tomography (CT) was able to demonstrate a small renal cell carcinoma as the cause of a spontaneous subcapsular hematoma. Angiographic and pathologic correlation were obtained. A review of the causes for nontraumatic renal subcapsular hematoma is included

  20. Cranium-brain trauma in computed tomographs - diagnosis and clinical correlation

    International Nuclear Information System (INIS)

    Wrasse, K.

    1982-01-01

    For the successful treatment of intracranial complications in the case of cranium-brain trauma a quick and exact diagnosis is necessary. The goal of this work was to test and evaluate the effectivity of computed tomography for neurotraumatology. Using 565 patients, who were acutely or at one time suffering from a cranium-brain trauma, the high validity of computed tomography for these injuries was proven. The following areas in question were studied with respect to the value of computed tomography in comparison to them: angiography, X-ray diagnostic, echoencephalography, brain scintigraphy, electroencephalography and neurological-psychopathological findings from cranium-brain trauma. Statement possibilities and difficulties of computed tomography are discussed in the cases of the following neurotraumatological diseases: extracranial hematomas; acute cranium-brain traumas; traumatic arachnoidal bleeding; diffuse brain edema; transtentorial herniation and brain contusions. At the end the diagnostic and therapeutic procedures in the case of cranium-brain trauma are presented. (orig.) [de

  1. Echocardiographic and non-gated computed tomographic findings of intrapericardial tumor and mediastinal tumor adjacent to the heart

    International Nuclear Information System (INIS)

    Ueda, Minoru; Yamada, Nobuyuki; Saito, Daiji; Haraoka, Shoichi; Tanetani, Setsuro.

    1981-01-01

    Echocardiographic and computed tomographic findings of a case of intrapericardial tumor are reported, and two other cases of mediastinal tumor are presented in a discussion of the differential diagnosis of intrapericardial from mediastinal tumors. Case report: A 7-year-old male complained of cough and dyspnea. Cardiomegaly had been pointed out at a mass X-ray examination about a month prior to the admission. Two-dimensional echocardiography revealed a massive anterior pericardial effusion and a fist-sized tumor with cystic structure. The tumor pushed the heart backward at the level of the aortic root. Non-gated computed tomography of the chest disclosed the size and location of the tumor, but failed to clarify the internal structure. The patient underwent successful removal of a tumor, 12 x 10 x 8 cm in size and 350 g in weight, originating from the left atrial wall. Histologically, the tumor was a fibrosarcomatous mesothelioma. Usually, an intrapericardial tumor is easily suspected by echocardiography by the presence of pericardial effusion, although there have been a few reports of intrapericardial tumors without pericardial effusion. Echocardiographic diagnosis of the intrapericardial tumor is difficult in such cases. Identification of the pericardium is necessary to diagnose whether a tumor is intra- or extrapericardial. This identification, however, is not always easy by echocardiography when the ultrasonic beams become tangent to the pericardium. The pericardium between the tumor and the heart could not be identified by echocardiography in our two cases of mediastinal tumor. Computed tomography is helpful in diagnosing the size and location of a mediastinal tumor. (author)

  2. Robust statistical reconstruction for charged particle tomography

    Science.gov (United States)

    Schultz, Larry Joe; Klimenko, Alexei Vasilievich; Fraser, Andrew Mcleod; Morris, Christopher; Orum, John Christopher; Borozdin, Konstantin N; Sossong, Michael James; Hengartner, Nicolas W

    2013-10-08

    Systems and methods for charged particle detection including statistical reconstruction of object volume scattering density profiles from charged particle tomographic data to determine the probability distribution of charged particle scattering using a statistical multiple scattering model and determine a substantially maximum likelihood estimate of object volume scattering density using expectation maximization (ML/EM) algorithm to reconstruct the object volume scattering density. The presence of and/or type of object occupying the volume of interest can be identified from the reconstructed volume scattering density profile. The charged particle tomographic data can be cosmic ray muon tomographic data from a muon tracker for scanning packages, containers, vehicles or cargo. The method can be implemented using a computer program which is executable on a computer.

  3. Computed tomographic criteria for differential diagnosis between exacerbation of focal chronic pancreatitis and carcinoma located in the head of the pancreas

    International Nuclear Information System (INIS)

    Ivanov, A.; Tonchev, Z.

    1995-01-01

    A group of 126 patients with CT-finding of tumor mass in the head of the pancreas is studied. Signs of acute exacerbation of focal chronic pancreatitis are found in 28 of them. Carcinoma of the head of pancreas is diagnosed in 98 patients. Surgical and histological verification is performed in 84 (86%) patients with carcinoma of the pancreas. In 77 (92%) cases the computed tomographic diagnosis coincides with the histological one, while in the remaining 7 (8%) it fails to coincide. The morphological and densitometric changes were analyzed with respect to their frequency. On account of the nonspecific character of the computed tomographic signs a symptom constellation is developed which facilitates the differential diagnosis of the acute exacerbation of focal pancreatitis and the carcinoma. The changes in density of lesions observed after application of contrast media were found to be of significant value. 16 refs., 6 figs. (author)

  4. Analysis of factors influencing the integrated bolus peak timing in contrast-enhanced brain computed tomographic angiography

    International Nuclear Information System (INIS)

    Son, Soon Yong; Choi, Kwan Woo; Jeong, Hoi Woun; Jang, Seo Goo; Jung, Jae Young; Yun, Jung Soo; Kim, Ki Won; Lee, Young Ah; Son, Jin Hyun; Min, Jung Whan

    2016-01-01

    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

  5. The use of intraosseous needles for injection of contrast media for computed tomographic angiography of the thoracic aorta.

    Science.gov (United States)

    Winkler, Michael; Talley, Cynthia; Woodward, Connor; Kingsbury, Alexander; Appiah, Frank; Elbelasi, Hossam; Landwher, Kevin; Li, Xingzhe; Fleischmann, Dominik

    The objective of this study is to evaluate the safety and quality of computed tomographic angiography of the thoracic aorta (CTA-TA) exams performed using intraosseous needle intravenous access (ION-IVA) for contrast media injection (CMI). All CTA-TA exams at the study institution performed between 1/1/2013 and 8/14/2015 were reviewed retrospectively to identify those exams which had been performed using ION-IVA (ION-exams). ION-exams were then analyzed to determine aortic attenuation and contrast-to-noise ratio (CNR). Linear regression was used to determine how injection rate and other variables affected image quality for ION-exams. Patient electronic medical records were reviewed to identify any adverse events related to CTA-TA or ION-IVA. 17 (∼0.2%) of 7401 exams were ION-exams. ION-exam CMI rates varied between 2.5 and 4 ml/s. Mean attenuation was 312 HU (SD 88 HU) and mean CNR was 25 (SD 9.9). A strong positive linear association between attenuation and injection rate was found. No immediate or delayed complications related to the ION-exams, or intraosseous needle use in general, occurred. For CTA-TA, ION-IVA appears to be a safe and effective route for CMI at rates up to 4 ml/s. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  6. Deviations of Mesial Root Canals of Mandibular First Molar Teeth at the Apical Third: A Micro-computed Tomographic Study.

    Science.gov (United States)

    Keles, Ali; Keskin, Cangül

    2018-04-19

    The present study aimed to quantitatively analyze apical foramen deviations of mesial root canals of mandibular first molar teeth by means of micro-computed tomographic (micro-CT) imaging. Micro-CT images of the mesial roots of 109 mandibular first molar teeth with independent mesiobuccal (MB) and mesiolingual (ML) root canals were analyzed. The deviations of the apical foramina of the MB, ML, and middle mesial root canals from the anatomic apex were measured. The vertical distance between the apical foramina of each mesial root canal in relation to each other was also calculated. The distances from the apical foramina of the MB, ML, and middle mesial root canals to the anatomic apex of the mesial root were up to 2.51 mm, 3.21 mm, and 5.67 mm, respectively. There was no significant difference between the deviations of MB and ML root canals from each other (P > .05). The middle mesial root canal showed the greatest deviation compared with the MB and ML canals (P < .05). The apical foramina of mesial root canals of mandibular first molar teeth showed greater variations from each other and anatomic apices than previously reported. Clinically, the use of electronic apex locators for the detection of minor apical foramen of each mesial root canal is of the utmost important. Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  7. Detectability of Middle Mesial Root Canal Orifices by Troughing Technique in Mandibular Molars: A Micro-computed Tomographic Study.

    Science.gov (United States)

    Keleş, Ali; Keskin, Cangül

    2017-08-01

    The objective of the present study was to measure the orifice depth of middle mesial canals (MMCs) and evaluate the detectability of orifices using troughing preparation. For this study, 85 mandibular molar teeth with MMCs were selected from the scanned micro-computed tomographic images. The MMCs were categorized, and the distances between the MMC orifices and the cementoenamel junctions (CEJ) were recorded as the depth of the orifice. Data were evaluated with frequency analysis and a chi-square test using SPSS (SPSS Inc, Chicago, IL), and the results indicated a 5% significance level. It was found that 77.41% of the MMC orifices were at the CEJ level, whereas 5.38% and 9.69% of the MMC orifices were detectable within 1-mm and 2-mm depths from the CEJ, respectively. Of the specimens, 7.52% had MMC orifices deeper than 2 mm from the CEJ. Confluent anatomy was the most frequent configuration. No significant relation was detected between the orifice depth and MMC configuration (P > .05). It was concluded that 77.41% of the specimens did not require troughing preparation, the remaining 15.07% would require troughing, and 7.52% could not be accessed even with the troughing preparation. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  8. Computed tomographic features of the bony canal of the cochlear nerve in pediatric patients with unilateral sensorineural hearing loss

    International Nuclear Information System (INIS)

    Kono, Tatsuo

    2008-01-01

    The aim of this study was to evaluate the diameters of the various bony canals of the inner ear in patients with sensorineural hearing loss (SNHL) and establish criteria for detecting hypoplasia of the bony canal of the cochlear nerve. Measurements obtained in 118 patients without inner ear malformations among 160 patients with unilateral SNHL were analyzed. The diameters of the internal auditory canal and the bony canals of the cochlear, vestibular, and facial nerves were measured on transverse or coronal computed tomographic images. Mean values (±standard deviation (SD)) were compared between the affected and unaffected ears, and statistical analysis was done. The diameter of the bony canal of the cochlear nerve was significantly smaller in affected ears than in unaffected ears (P<0.01). The affected ears could be divided into groups with (72 ears) and without (46 ears) bony canal stenosis. Most (60%) of the patients with unilateral SNHL showed a significant difference in the diameters of the bony canals of the cochlear nerve between the affected and unaffected sides; moreover, the mean value was significantly smaller in affected ears. The diameter of <1.7 mm on transverse images or <1.8 mm on coronal images suggests hypoplasia. (author)

  9. Impact of Cardiac Computed Tomographic Angiography Findings on Planning of Cancer Therapy in Patients with Concomitant Structural Heart Disease

    Directory of Open Access Journals (Sweden)

    Iyad N. Daher

    2011-01-01

    Full Text Available Background. Exclusion of underlying coronary artery disease (CAD is essential in the diagnosis of chemotherapy-induced cardiomyopathy. Presence and severity of CAD can also impact the choice of therapy in cancer patients. The value of cardiac computed tomographic angiography (CCTA in this setting has not been reported. Methods. We collected data on the clinical presentation and indications for CCTA performed from January to December 2008 at the University of Texas MD Anderson Cancer Center (MDACC. All examinations were performed using a 64-detector scanner. CCTA results and subsequent treatment decisions were examined. Results. A total of 80 patients underwent CCTA during the study period for the following indications (not mutually exclusive: cardiomyopathy of unknown etiology in 33 pts (41.3%, chest pain in 32 (40.0%, abnormal stress test in 16 (20.0%, abnormal cardiac markers in 8 (10.0%, suspected cardiac mass or thrombus in 7 (8.8%. Chemotherapy-induced cardiomyopathy was diagnosed in 18 pts (22.5%. Severe CAD was detected in 22 pts (27.5%; due to concomitant advanced cancer or patient refusal, only 12 underwent coronary angiogram. Of these, 4 pts (5% of total underwent coronary artery bypass grafting. A total of 41 pts (51.3% had their cancer management altered based on CCTA findings. Conclusion. CCTA is useful in evaluating cancer pts with structural heart disease and can have an impact on the management of cancer and cardiac disease.

  10. Is triple contrast computed tomographic scanning useful in the selective management of stab wounds to the back?

    Science.gov (United States)

    McAllister, E; Perez, M; Albrink, M H; Olsen, S M; Rosemurgy, A S

    1994-09-01

    We devised a protocol to prospectively manage stab wounds to the back with the hypothesis that the triple contrast computed tomographic (CT) scan is an effective means of detecting occult injury in these patients. All wounds to the back in hemodynamically stable adults were locally explored. All patients with muscular fascial penetration underwent triple contrast CT scanning utilizing oral, rectal, and IV contrast. Patients did not undergo surgical exploration if their CT scan was interpreted as negative or if the CT scan demonstrated injuries not requiring surgical intervention. Fifty-three patients were entered into the protocol. The time to complete the triple contrast CT scan ranged from 3 to 6 hours at a cost of $1050 for each scan. In 51 patients (96%), the CT scan either had negative findings (n = 31) or showed injuries not requiring exploration (n = 20). These patients did well with nonsurgical management. Two CT scans documented significant injury and led to surgical exploration and therapeutic celiotomies. Although triple contrast CT scanning was able to detect occult injury in patients with stab wounds to the back it did so at considerable cost and the results rarely altered clinical care. Therefore, its routine use in these patients is not recommended.

  11. Lung Ultrasonography in Patients With Idiopathic Pulmonary Fibrosis: Evaluation of a Simplified Protocol With High-Resolution Computed Tomographic Correlation.

    Science.gov (United States)

    Vassalou, Evangelia E; Raissaki, Maria; Magkanas, Eleftherios; Antoniou, Katerina M; Karantanas, Apostolos H

    2018-03-01

    To compare a simplified ultrasonographic (US) protocol in 2 patient positions with the same-positioned comprehensive US assessments and high-resolution computed tomographic (CT) findings in patients with idiopathic pulmonary fibrosis. Twenty-five consecutive patients with idiopathic pulmonary fibrosis were prospectively enrolled and examined in 2 sessions. During session 1, patients were examined with a US protocol including 56 lung intercostal spaces in supine/sitting (supine/sitting comprehensive protocol) and lateral decubitus (decubitus comprehensive protocol) positions. During session 2, patients were evaluated with a 16-intercostal space US protocol in sitting (sitting simplified protocol) and left/right decubitus (decubitus simplified protocol) positions. The 16 intercostal spaces were chosen according to the prevalence of idiopathic pulmonary fibrosis-related changes on high-resolution CT. The sum of B-lines counted in each intercostal space formed the US scores for all 4 US protocols: supine/sitting and decubitus comprehensive US scores and sitting and decubitus simplified US scores. High-resolution CT-related Warrick scores (J Rheumatol 1991; 18:1520-1528) were compared to US scores. The duration of each protocol was recorded. A significant correlation was found between all US scores and Warrick scores and between simplified and corresponding comprehensive scores (P idiopathic pulmonary fibrosis. The 16-intercostal space simplified protocol in the lateral decubitus position correlated better with high-resolution CT findings and was less time-consuming compared to the sitting position. © 2017 by the American Institute of Ultrasound in Medicine.

  12. Comparison of the Multidetector-row Computed Tomographic Angiography Axial and Coronal Planes' Usefulness for Detecting Thoracodorsal Artery Perforators

    Science.gov (United States)

    Kim, Jong Gyu

    2012-01-01

    Background During the planning of a thoracodorsal artery perforator (TDAP) free flap, preoperative multidetector-row computed tomographic (MDCT) angiography is valuable for predicting the locations of perforators. However, CT-based perforator mapping of the thoracodorsal artery is not easy because of its small diameter. Thus, we evaluated 1-mm-thick MDCT images in multiple planes to search for reliable perforators accurately. Methods Between July 2010 and October 2011, 19 consecutive patients (13 males, 6 females) who underwent MDCT prior to TDAP free flap operations were enrolled in this study. Patients ranged in age from 10 to 75 years (mean, 39.3 years). MDCT images were acquired at a thickness of 1 mm in the axial, coronal, and sagittal planes. Results The thoracodorsal artery perforators were detected in all 19 cases. The reliable perforators originating from the descending branch were found in 14 cases, of which 6 had transverse branches. The former were well identified in the coronal view, and the latter in the axial view. The location of the most reliable perforators on MDCT images corresponded well with the surgical findings. Conclusions Though MDCT has been widely used in performing the abdominal perforator free flap for detecting reliable perforating vessels, it is not popular in the TDAP free flap. The results of this study suggest that multiple planes of MDCT may increase the probability of detecting the most reliable perforators, along with decreasing the probability of missing available vessels. PMID:22872839

  13. Clinical and high-resolution computed tomographic findings in five patients with pulmonary tuberculosis who developed respiratory failure following chemotherapy

    International Nuclear Information System (INIS)

    Akira, Masanori; Sakatani, Mitsunori

    2001-01-01

    AIM: The purpose of this study was to describe the clinical and high-resolution computed tomographic (HRCT) findings in patients with pulmonary tuberculosis who developed respiratory failure after starting chemotherapy. MATERIALS AND METHODS: The clinical records, chest radiographs, and HRCT findings in five patients with non-miliary pulmonary tuberculosis who developed respiratory failure after starting chemotherapy were reviewed. RESULTS: Chest radiographs taken early in the course of acute respiratory failure showed progression of the original lesions with (n = 4) or without (n = 1) new areas of opacity away from the site of the original lesions. HRCT demonstrated widespread ground-glass attenuation with a reticular pattern as well as segmental or lobar consolidation with cavitation and nodules, consistent with active tuberculous foci in all five cases. Prominent interlobular septal thickening was seen in two cases. Four of the five patients had received corticosteroids. Of these five, two died and three recovered with continued corticosteroid therapy. Transbronchial biopsy in three cases showed evidence of acute alveolar damage. CONCLUSION: In selected patients with tuberculosis who develop respiratory failure following the initiation of antituberculous therapy, HRCT may be a helpful adjunct to clinical evaluation in differentiating hypersensitivity reactions (presumed to be due to the release of mycobacterial antigens) from other pulmonary complications. Akira, M. and Sakatani, M. (2001)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Verification of computed tomographic estimates of cochlear implant array position: a micro-CT and histologic analysis.

    Science.gov (United States)

    Teymouri, Jessica; Hullar, Timothy E; Holden, Timothy A; Chole, Richard A

    2011-08-01

    To determine the efficacy of clinical computed tomographic (CT) imaging to verify postoperative electrode array placement in cochlear implant (CI) patients. Nine fresh cadaver heads underwent clinical CT scanning, followed by bilateral CI insertion and postoperative clinical CT scanning. Temporal bones were removed, trimmed, and scanned using micro-CT. Specimens were then dehydrated, embedded in either methyl methacrylate or LR White resin, and sectioned with a diamond wafering saw. Histology sections were examined by 3 blinded observers to determine the position of individual electrodes relative to soft tissue structures within the cochlea. Electrodes were judged to be within the scala tympani, scala vestibuli, or in an intermediate position between scalae. The position of the array could be estimated accurately from clinical CT scans in all specimens using micro-CT and histology as a criterion standard. Verification using micro-CT yielded 97% agreement, and histologic analysis revealed 95% agreement with clinical CT results. A composite, 3-dimensional image derived from a patient's preoperative and postoperative CT images using a clinical scanner accurately estimates the position of the electrode array as determined by micro-CT imaging and histologic analyses. Information obtained using the CT method provides valuable insight into numerous variables of interest to patient performance such as surgical technique, array design, and processor programming and troubleshooting.

  16. Positional relationship between the maxillary sinus floor and the apex of the maxillary first molar using cone beam computed tomograph

    International Nuclear Information System (INIS)

    Kim, Kyung Hwa; Koh, Kwang Joon

    2008-01-01

    To assess the positional relationship between the maxillary sinus floor and the apex of the maxillary first molar using cone beam computed tomograph (CBCT). CBCTs from 127 subjects were analysed. A total of 134 maxillary first molars were classified according to their vertical and horizontal positional relationship to the maxillary sinus floor and measured according to the distance between the maxillary sinus floor and the maxillary first molar. Type III (The root projected laterally on the sinus cavity but its apex is outside the sinus boundaries) was dominated between 10 and 19 years and type I (The root apex was not in contact with the cortical borders of the sinus) was dominated (P<0.05) between 20 and 72 years on the vertical relationship between the maxillary sinus floor and the apex of the maxillary first molar. The maxillary sinus floor was located more at the apex (78.2%) than at the furcation (21.3%) for the palatal root. The distance from the root apex to the maxillary sinus floor confined to type I was increased according to the ages (P<0.05). Type M (The maxillary sinus floor was located between the buccal and the palatal root) was most common (72.4%) on the horizontal relationship between the maxillary sinus floor and the apex of the maxillary first molar. CBCT can provide highly qualified images for the maxillary sinus floor and the root apex of the maxillary first molar.

  17. Computer tomographic investigation of subcutaneous adipose tissue as an indicator of body composition

    DEFF Research Database (Denmark)

    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...... adipose tissue at a specific site measured by ultrasound, is used in the pig industry to assess adiposity and inform management decisions that have an impact on reproduction, food conversion performance and sow longevity. The measurement site, called "P2", is used throughout the industry. We propose...... 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...

  18. Whole body computed tomographic findings of each one case with primary aldosteronism and Cushing syndrome

    International Nuclear Information System (INIS)

    Kamata, Shuji; Kawamura, Koro; Nakamura, Motoyuki

    1980-01-01

    We here report each one case with primary aldosteronism (male, 28 years old) and Cushing syndrome (female, 37 years old). Both of the cases showed characteristic clinical signs of hypertension and typical laboratory findings of adreno-hormonal assays. In performance of whole body computed tomography, clear pictures of tumorous adenomas in both cases were taken and the sizes of adenomas in picture were completely same as the masses obtained by the lateral adrenectomies. As a result, the whole body computed tomography is very useful to diagnose the diseases of adrenal adenoma and hyperplasia. (author)

  19. Computed tomographic evaluation of comminuted middle phalangeal fractures in the horse

    International Nuclear Information System (INIS)

    Rose, P.L.; Seeherman, H.; O'Callaghan, M.

    1997-01-01

    Comminuted fractures of the middle phalanx have been well described in the horse. Choice of treatment, surgical planning and prognosis have traditionally been based upon evaluation of radiographs. However, the complex nature of comminuted fractures makes radiographic interpretation difficult. Computed tomography (CT) allows the production of cross-sectional images with spatial separation of structures which are superimposed on survey radiographs. This allows accurate assessment of the number and direction of fracture lines within the bone. In this paper we report the use of CT in the evaluation of 6 comminuted middle phalangeal fractures. Computed tomography is potentially useful in deciding the type of treatment, surgical planning and determining the prognosis

  20. Middle east respiratory syndrome-corona virus infection: A case report of sieral computed tomographic findings in a young male patient

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Central tarsal bone fractures in horses not used for racing: Computed tomographic configuration and long-term outcome of lag screw fixation

    OpenAIRE

    Gunst, S; Del Chicca, Francesca; Fürst, Anton; Kuemmerle, Jan M

    2016-01-01

    REASONS FOR PERFORMING STUDY: There are no reports on the configuration of equine central tarsal bone fractures based on cross-sectional imaging and clinical and radiographic long-term outcome after internal fixation. OBJECTIVES: To report clinical, radiographic and computed tomographic findings of equine central tarsal bone fractures and to evaluate the long-term outcome of internal fixation. STUDY DESIGN: Retrospective case series. METHODS: All horses diagnosed with a central tarsa...

  2. Iterative reconstruction with boundary detection for carbon ion computed tomography

    Science.gov (United States)

    Shrestha, Deepak; Qin, Nan; Zhang, You; Kalantari, Faraz; Niu, Shanzhou; Jia, Xun; Pompos, Arnold; Jiang, Steve; Wang, Jing

    2018-03-01

    In heavy ion radiation therapy, improving the accuracy in range prediction of the ions inside the patient’s body has become essential. Accurate localization of the Bragg peak provides greater conformity of the tumor while sparing healthy tissues. We investigated the use of carbon ions directly for computed tomography (carbon CT) to create the relative stopping power map of a patient’s body. The Geant4 toolkit was used to perform a Monte Carlo simulation of the carbon ion trajectories, to study their lateral and angular deflections and the most likely paths, using a water phantom. Geant4 was used to create carbonCT projections of a contrast and spatial resolution phantom, with a cone beam of 430 MeV/u carbon ions. The contrast phantom consisted of cranial bone, lung material, and PMMA inserts while the spatial resolution phantom contained bone and lung material inserts with line pair (lp) densities ranging from 1.67 lp cm-1 through 5 lp cm-1. First, the positions of each carbon ion on the rear and front trackers were used for an approximate reconstruction of the phantom. The phantom boundary was extracted from this approximate reconstruction, by using the position as well as angle information from the four tracking detectors, resulting in the entry and exit locations of the individual ions on the phantom surface. Subsequent reconstruction was performed by the iterative algebraic reconstruction technique coupled with total variation minimization (ART-TV) assuming straight line trajectories for the ions inside the phantom. The influence of number of projections was studied with reconstruction from five different sets of projections: 15, 30, 45, 60 and 90. Additionally, the effect of number of ions on the image quality was investigated by reducing the number of ions/projection while keeping the total number of projections at 60. An estimation of carbon ion range using the carbonCT image resulted in improved range prediction compared to the range calculated using a

  3. Computational methods for three-dimensional microscopy reconstruction

    CERN Document Server

    Frank, Joachim

    2014-01-01

    Approaches to the recovery of three-dimensional information on a biological object, which are often formulated or implemented initially in an intuitive way, are concisely described here based on physical models of the object and the image-formation process. Both three-dimensional electron microscopy and X-ray tomography can be captured in the same mathematical framework, leading to closely-related computational approaches, but the methodologies differ in detail and hence pose different challenges. The editors of this volume, Gabor T. Herman and Joachim Frank, are experts in the respective methodologies and present research at the forefront of biological imaging and structural biology.   Computational Methods for Three-Dimensional Microscopy Reconstruction will serve as a useful resource for scholars interested in the development of computational methods for structural biology and cell biology, particularly in the area of 3D imaging and modeling.

  4. Comparison of computer tomographic and patho-anatomic pathomorphology of the hypernephroid renal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Jaschke, W.; Moeller, P.; Palmtag, H.; Kaick, G. van

    1980-11-01

    Knowledge of the patho-anatomic variants of the hypernephroid renal carcinoma as well as of its computertomographic correlate facilitates diagnosis and prevents fatal diagnostic errors. Measurements of density by computer tomography, as well as on-target application of contrast medium, are of great importance for arriving at the correct diagnosis.

  5. Comparison of computer tomographic and patho-anatomic pathomorphology of the hypernephroid renal carcinoma

    International Nuclear Information System (INIS)

    Jaschke, W.; Moeller, P.; Palmtag, H.; Kaick, G. van; Heidelberg Univ.

    1980-01-01

    Knowledge of the patho-anatomic variants of the hypernephroid renal carcinoma as well as of its computertomographic correlate facilitates diagnosis and prevents fatal diagnostic errors. Measurements of density by computer tomography, as well as on-target application of contrast medium, are of great importance for arriving at the correct diagnosis. (orig.) [de

  6. Computed tomographic demonstration of rapid changes in fatty infiltration of the liver

    International Nuclear Information System (INIS)

    Bashist, B.; Hecht, H.L.; Harely, W.D.

    1982-01-01

    Two alcoholic patients in whom computed tomography (CT) demonstrated reversal of fatty infiltration of the liver are described. The rapid reversibility of fatty infiltration can be useful in monitoring alcoholics with fatty livers. Focal fatty infiltration can mimic focal hepatic lesions and repeat scans can be utilized to assess changes in CT attenuation values when this condition is suspected

  7. Four-dimensional computed tomographic analysis of esophageal mobility during normal respiration

    NARCIS (Netherlands)

    Dieleman, Edith M. T.; Senan, Suresh; Vincent, Andrew; Lagerwaard, Frank J.; Slotman, Ben J.; van Sörnsen de Koste, John R.

    2007-01-01

    BACKGROUND: Chemo-radiotherapy for thoracic tumors can result in high-grade radiation esophagitis. Treatment planning to reduce esophageal irradiation requires organ motion to be accounted for. In this study, esophageal mobility was assessed using four-dimensional computed tomography (4DCT). METHODS

  8. Computed tomographic aspects of primary brain tumors in dogs and cats

    International Nuclear Information System (INIS)

    Babicsak, Viviam Rocco; Zardo, Karen Maciel; Santos, Debora Rodrigues dos; Silva, Luciana Carandina da; Machado, Vania Maria de Vasconcelos; Vulcano, Luiz Carlos

    2011-01-01

    Over the years, the Veterinary Medicine has made great advances, enabling thus the diagnosis of many diseases. As a result of this new situation, there was an increased expectation of life of animals resulting in an increase in the number of clinical care of older animals. Thus, diseases considered unusual in the past, begin to be diagnosed more frequently, as is the case of brain damage. Recently, computed tomography has been widely used in Brazil as a tool to aid in the diagnosis of several diseases. This noninvasive imaging technique allows the identification and evaluation of lesions of central nervous tissue such as brain tumors. This provides information about the size, shape and location of the lesion, in addition to the magnitude of compression and invasion of adjacent structures by the tumor and its side effects (such as the peritumoral edema and hydrocephalus). The image obtained from computed tomography may suggest the presence of a certain type brain tumor, data of great importance for the prognosis and treatment of the animal. This review covers the computed tomography aspects of primary brain tumors such as meningiomas, astrocytomas, oligodendrogliomas, choroid plexus tumors and ependymomas. However, despite the computed tomography provide much information about the changes inside the skull; no way replace histopathological examination in determining the definitive diagnosis. (author)

  9. Sonographic and computed tomographic features of embryonal rhabdomyosarcoma of the biliary tract

    International Nuclear Information System (INIS)

    Friedburg, H.; Kauffmann, G.W.; Boehm, N.; Fiedler, L.; Jobke, A.

    1984-01-01

    3-year-old child presented with vague abdominal pain, fever, leucocytosis and elevation of alkaline phosphatase. Ultrasonography revealed a space occupying process within the extrahepatic bile ducts surrounded by fluid. Various densities (between 15-25 Hounsfield units) were measured in this intrabiliary tumor by computed tomography. (orig.)

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

    Science.gov (United States)

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

    2016-01-01

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

  11. Tomographic anthropomorphic models. Pt. 1

    International Nuclear Information System (INIS)

    Veit, R.; Zankl, M.; Petoussi, N.; Mannweiler, E.; Drexler, G.; Williams, G.

    1989-01-01

    The first generation of heterogenoeous anthropomorphic mathematical models to be used in dose calculations was the MIRD-5 adult phantom, followed