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Sample records for vessel size imaging

  1. Validation of the Gatortail method for accurate sizing of pulmonary vessels from 3D medical images.

    Science.gov (United States)

    O'Dell, Walter G; Gormaley, Anne K; Prida, David A

    2017-12-01

    Detailed characterization of changes in vessel size is crucial for the diagnosis and management of a variety of vascular diseases. Because clinical measurement of vessel size is typically dependent on the radiologist's subjective interpretation of the vessel borders, it is often prone to high inter- and intra-user variability. Automatic methods of vessel sizing have been developed for two-dimensional images but a fully three-dimensional (3D) method suitable for vessel sizing from volumetric X-ray computed tomography (CT) or magnetic resonance imaging has heretofore not been demonstrated and validated robustly. In this paper, we refined and objectively validated Gatortail, a method that creates a mathematical geometric 3D model of each branch in a vascular tree, simulates the appearance of the virtual vascular tree in a 3D CT image, and uses the similarity of the simulated image to a patient's CT scan to drive the optimization of the model parameters, including vessel size, to match that of the patient. The method was validated with a 2-dimensional virtual tree structure under deformation, and with a realistic 3D-printed vascular phantom in which the diameter of 64 branches were manually measured 3 times each. The phantom was then scanned on a conventional clinical CT imaging system and the images processed with the in-house software to automatically segment and mathematically model the vascular tree, label each branch, and perform the Gatortail optimization of branch size and trajectory. Previously proposed methods of vessel sizing using matched Gaussian filters and tubularity metrics were also tested. The Gatortail method was then demonstrated on the pulmonary arterial tree segmented from a human volunteer's CT scan. The standard deviation of the difference between the manually measured and Gatortail-based radii in the 3D physical phantom was 0.074 mm (0.087 in-plane pixel units for image voxels of dimension 0.85 × 0.85 × 1.0 mm) over the 64 branches

  2. Vessel size measurements in angiograms: A comparison of techniques

    International Nuclear Information System (INIS)

    Hoffmann, Kenneth R.; Nazareth, Daryl P.; Miskolczi, Laszlo; Gopal, Anant; Wang Zhou; Rudin, Stephen; Bednarek, Daniel R.

    2002-01-01

    As interventional procedures become more complicated, the need for accurate quantitative vascular information increases. In response to this need, many commercial vendors provide techniques for measurement of vessel sizes, usually based on derivative techniques. In this study, we investigate the accuracy of several techniques used in the measurement of vessel size. Simulated images of vessels having circular cross sections were generated and convolved with various focal spot distributions taking into account the magnification. These vessel images were then convolved with Gaussian image detector line spread functions (LSFs). Additionally, images of a phantom containing vessels with a range of diameters were acquired for the 4.5'', 6'', 9'', and 12'' modes of an image intensifier-TV (II-TV) system. Vessel sizes in the images were determined using a first-derivative technique, a second-derivative technique, a linear combination of these two measured sizes, a thresholding technique, a densitometric technique, and a model-based technique. For the same focal spot size, the shape of the focal spot distribution does not affect measured vessel sizes except at large magnifications. For vessels with diameters larger than the full-width-at-half-maximum (FWHM) of the LSF, accurate vessel sizes (errors ∼0.1 mm) could be obtained by using an average of sizes determined by the first and second derivatives. For vessels with diameters smaller than the FWHM of the LSF, the densitometric and model-based techniques can provide accurate vessel sizes when these techniques are properly calibrated

  3. Vessel size measurements in angiograms: Manual measurements

    International Nuclear Information System (INIS)

    Hoffmann, Kenneth R.; Dmochowski, Jacek; Nazareth, Daryl P.; Miskolczi, Laszlo; Nemes, Balazs; Gopal, Anant; Wang Zhou; Rudin, Stephen; Bednarek, Daniel R.

    2003-01-01

    Vessel size measurement is perhaps the most often performed quantitative analysis in diagnostic and interventional angiography. Although automated vessel sizing techniques are generally considered to have good accuracy and precision, we have observed that clinicians rarely use these techniques in standard clinical practice, choosing to indicate the edges of vessels and catheters to determine sizes and calibrate magnifications, i.e., manual measurements. Thus, we undertook an investigation of the accuracy and precision of vessel sizes calculated from manually indicated edges of vessels. Manual measurements were performed by three neuroradiologists and three physicists. Vessel sizes ranged from 0.1-3.0 mm in simulation studies and 0.3-6.4 mm in phantom studies. Simulation resolution functions had full-widths-at-half-maximum (FWHM) ranging from 0.0 to 0.5 mm. Phantom studies were performed with 4.5 in., 6 in., 9 in., and 12 in. image intensifier modes, magnification factor = 1, with and without zooming. The accuracy and reproducibility of the measurements ranged from 0.1 to 0.2 mm, depending on vessel size, resolution, and pixel size, and zoom. These results indicate that manual measurements may have accuracies comparable to automated techniques for vessels with sizes greater than 1 mm, but that automated techniques which take into account the resolution function should be used for vessels with sizes smaller than 1 mm

  4. Distribution of normal superficial ocular vessels in digital images.

    Science.gov (United States)

    Banaee, Touka; Ehsaei, Asieh; Pourreza, Hamidreza; Khajedaluee, Mohammad; Abrishami, Mojtaba; Basiri, Mohsen; Daneshvar Kakhki, Ramin; Pourreza, Reza

    2014-02-01

    To investigate the distribution of different-sized vessels in the digital images of the ocular surface, an endeavor which may provide useful information for future studies. This study included 295 healthy individuals. From each participant, four digital photographs of the superior and inferior conjunctivae of both eyes, with a fixed succession of photography (right upper, right lower, left upper, left lower), were taken with a slit lamp mounted camera. Photographs were then analyzed by a previously described algorithm for vessel detection in the digital images. The area (of the image) occupied by vessels (AOV) of different sizes was measured. Height, weight, fasting blood sugar (FBS) and hemoglobin levels were also measured and the relationship between these parameters and the AOV was investigated. These findings indicated a statistically significant difference in the distribution of the AOV among the four conjunctival areas. No significant correlations were noted between the AOV of each conjunctival area and the different demographic and biometric factors. Medium-sized vessels were the most abundant vessels in the photographs of the four investigated conjunctival areas. The AOV of the different sizes of vessels follows a normal distribution curve in the four areas of the conjunctiva. The distribution of the vessels in successive photographs changes in a specific manner, with the mean AOV becoming larger as the photos were taken from the right upper to the left lower area. The AOV of vessel sizes has a normal distribution curve and medium-sized vessels occupy the largest area of the photograph. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  5. Distribution of Different Sized Ocular Surface Vessels in Diabetics and Normal Individuals.

    Science.gov (United States)

    Banaee, Touka; Pourreza, Hamidreza; Doosti, Hassan; Abrishami, Mojtaba; Ehsaei, Asieh; Basiry, Mohsen; Pourreza, Reza

    2017-01-01

    To compare the distribution of different sized vessels using digital photographs of the ocular surface of diabetic and normal individuals. In this cross-sectional study, red-free conjunctival photographs of diabetic and normal individuals, aged 30-60 years, were taken under defined conditions and analyzed using a Radon transform-based algorithm for vascular segmentation. The image areas occupied by vessels (AOV) of different diameters were calculated. The main outcome measure was the distribution curve of mean AOV of different sized vessels. Secondary outcome measures included total AOV and standard deviation (SD) of AOV of different sized vessels. Two hundred and sixty-eight diabetic patients and 297 normal (control) individuals were included, differing in age (45.50 ± 5.19 vs. 40.38 ± 6.19 years, P distribution curves of mean AOV differed between patients and controls (smaller AOV for larger vessels in patients; P distribution curve of vessels compared to controls. Presence of diabetes mellitus is associated with contraction of larger vessels in the conjunctiva. Smaller vessels dilate with diabetic retinopathy. These findings may be useful in the photographic screening of diabetes mellitus and retinopathy.

  6. An automated vessel segmentation of retinal images using multiscale vesselness

    International Nuclear Information System (INIS)

    Ben Abdallah, M.; Malek, J.; Tourki, R.; Krissian, K.

    2011-01-01

    The ocular fundus image can provide information on pathological changes caused by local ocular diseases and early signs of certain systemic diseases, such as diabetes and hypertension. Automated analysis and interpretation of fundus images has become a necessary and important diagnostic procedure in ophthalmology. The extraction of blood vessels from retinal images is an important and challenging task in medical analysis and diagnosis. In this paper, we introduce an implementation of the anisotropic diffusion which allows reducing the noise and better preserving small structures like vessels in 2D images. A vessel detection filter, based on a multi-scale vesselness function, is then applied to enhance vascular structures.

  7. Cerebral vessels segmentation for light-sheet microscopy image using convolutional neural networks

    Science.gov (United States)

    Hu, Chaoen; Hui, Hui; Wang, Shuo; Dong, Di; Liu, Xia; Yang, Xin; Tian, Jie

    2017-03-01

    Cerebral vessel segmentation is an important step in image analysis for brain function and brain disease studies. To extract all the cerebrovascular patterns, including arteries and capillaries, some filter-based methods are used to segment vessels. However, the design of accurate and robust vessel segmentation algorithms is still challenging, due to the variety and complexity of images, especially in cerebral blood vessel segmentation. In this work, we addressed a problem of automatic and robust segmentation of cerebral micro-vessels structures in cerebrovascular images acquired by light-sheet microscope for mouse. To segment micro-vessels in large-scale image data, we proposed a convolutional neural networks (CNNs) architecture trained by 1.58 million pixels with manual label. Three convolutional layers and one fully connected layer were used in the CNNs model. We extracted a patch of size 32x32 pixels in each acquired brain vessel image as training data set to feed into CNNs for classification. This network was trained to output the probability that the center pixel of input patch belongs to vessel structures. To build the CNNs architecture, a series of mouse brain vascular images acquired from a commercial light sheet fluorescence microscopy (LSFM) system were used for training the model. The experimental results demonstrated that our approach is a promising method for effectively segmenting micro-vessels structures in cerebrovascular images with vessel-dense, nonuniform gray-level and long-scale contrast regions.

  8. Molecular imaging of tumor blood vessels in prostate cancer.

    Science.gov (United States)

    Tilki, Derya; Seitz, Michael; Singer, Bernhard B; Irmak, Ster; Stief, Christian G; Reich, Oliver; Ergün, Süleyman

    2009-05-01

    In the past three decades many efforts have been undertaken to understand the mechanisms of tumor angiogenesis. The introduction of anti-angiogenic drugs in tumor therapy during the last few years necessitates the establishment of new techniques enabling molecular imaging of tumor vascular remodelling. The determination of tumor size as commonly used is not appropriate since the extended necrosis under anti-angiogenic therapy does not necessarily result in the reduction of tumor diameter. The basis for the molecular imaging of tumor blood vessels is the remodelling of the tumor vessels under anti-angiogenic therapy which obviously occurs at an early stage and seems to be a convincing parameter. Beside the enormous progress in this field during the last few years the resolution is still not high enough to evaluate the remodelling of the micro tumor vessels. New imaging approaches combining specific molecular markers for tumor vessels with the different imaging techniques are needed to overcome this issue as exemplarily discussed for prostate cancer in this review. Molecular contrast agents targeting the vasculature will allow clinicians the visualization of vascular remodelling processes taking place under anti-angiogenic therapy and improve tumor diagnosis and follow-up.

  9. NEAR REAL-TIME AUTOMATIC MARINE VESSEL DETECTION ON OPTICAL SATELLITE IMAGES

    Directory of Open Access Journals (Sweden)

    G. Máttyus

    2013-05-01

    Full Text Available Vessel monitoring and surveillance is important for maritime safety and security, environment protection and border control. Ship monitoring systems based on Synthetic-aperture Radar (SAR satellite images are operational. On SAR images the ships made of metal with sharp edges appear as bright dots and edges, therefore they can be well distinguished from the water. Since the radar is independent from the sun light and can acquire images also by cloudy weather and rain, it provides a reliable service. Vessel detection from spaceborne optical images (VDSOI can extend the SAR based systems by providing more frequent revisit times and overcoming some drawbacks of the SAR images (e.g. lower spatial resolution, difficult human interpretation. Optical satellite images (OSI can have a higher spatial resolution thus enabling the detection of smaller vessels and enhancing the vessel type classification. The human interpretation of an optical image is also easier than as of SAR image. In this paper I present a rapid automatic vessel detection method which uses pattern recognition methods, originally developed in the computer vision field. In the first step I train a binary classifier from image samples of vessels and background. The classifier uses simple features which can be calculated very fast. For the detection the classifier is slided along the image in various directions and scales. The detector has a cascade structure which rejects most of the background in the early stages which leads to faster execution. The detections are grouped together to avoid multiple detections. Finally the position, size(i.e. length and width and heading of the vessels is extracted from the contours of the vessel. The presented method is parallelized, thus it runs fast (in minutes for 16000 × 16000 pixels image on a multicore computer, enabling near real-time applications, e.g. one hour from image acquisition to end user.

  10. Near Real-Time Automatic Marine Vessel Detection on Optical Satellite Images

    Science.gov (United States)

    Máttyus, G.

    2013-05-01

    Vessel monitoring and surveillance is important for maritime safety and security, environment protection and border control. Ship monitoring systems based on Synthetic-aperture Radar (SAR) satellite images are operational. On SAR images the ships made of metal with sharp edges appear as bright dots and edges, therefore they can be well distinguished from the water. Since the radar is independent from the sun light and can acquire images also by cloudy weather and rain, it provides a reliable service. Vessel detection from spaceborne optical images (VDSOI) can extend the SAR based systems by providing more frequent revisit times and overcoming some drawbacks of the SAR images (e.g. lower spatial resolution, difficult human interpretation). Optical satellite images (OSI) can have a higher spatial resolution thus enabling the detection of smaller vessels and enhancing the vessel type classification. The human interpretation of an optical image is also easier than as of SAR image. In this paper I present a rapid automatic vessel detection method which uses pattern recognition methods, originally developed in the computer vision field. In the first step I train a binary classifier from image samples of vessels and background. The classifier uses simple features which can be calculated very fast. For the detection the classifier is slided along the image in various directions and scales. The detector has a cascade structure which rejects most of the background in the early stages which leads to faster execution. The detections are grouped together to avoid multiple detections. Finally the position, size(i.e. length and width) and heading of the vessels is extracted from the contours of the vessel. The presented method is parallelized, thus it runs fast (in minutes for 16000 × 16000 pixels image) on a multicore computer, enabling near real-time applications, e.g. one hour from image acquisition to end user.

  11. New algorithm for detecting smaller retinal blood vessels in fundus images

    Science.gov (United States)

    LeAnder, Robert; Bidari, Praveen I.; Mohammed, Tauseef A.; Das, Moumita; Umbaugh, Scott E.

    2010-03-01

    About 4.1 million Americans suffer from diabetic retinopathy. To help automatically diagnose various stages of the disease, a new blood-vessel-segmentation algorithm based on spatial high-pass filtering was developed to automatically segment blood vessels, including the smaller ones, with low noise. Methods: Image database: Forty, 584 x 565-pixel images were collected from the DRIVE image database. Preprocessing: Green-band extraction was used to obtain better contrast, which facilitated better visualization of retinal blood vessels. A spatial highpass filter of mask-size 11 was applied. A histogram stretch was performed to enhance contrast. A median filter was applied to mitigate noise. At this point, the gray-scale image was converted to a binary image using a binary thresholding operation. Then, a NOT operation was performed by gray-level value inversion between 0 and 255. Postprocessing: The resulting image was AND-ed with its corresponding ring mask to remove the outer-ring (lens-edge) artifact. At this point, the above algorithm steps had extracted most of the major and minor vessels, with some intersections and bifurcations missing. Vessel segments were reintegrated using the Hough transform. Results: After applying the Hough transform, both the average peak SNR and the RMS error improved by 10%. Pratt's Figure of Merit (PFM) was decreased by 6%. Those averages were better than [1] by 10-30%. Conclusions: The new algorithm successfully preserved the details of smaller blood vessels and should prove successful as a segmentation step for automatically identifying diseases that affect retinal blood vessels.

  12. Automatic Vessel Segmentation on Retinal Images

    Institute of Scientific and Technical Information of China (English)

    Chun-Yuan Yu; Chia-Jen Chang; Yen-Ju Yao; Shyr-Shen Yu

    2014-01-01

    Several features of retinal vessels can be used to monitor the progression of diseases. Changes in vascular structures, for example, vessel caliber, branching angle, and tortuosity, are portents of many diseases such as diabetic retinopathy and arterial hyper-tension. This paper proposes an automatic retinal vessel segmentation method based on morphological closing and multi-scale line detection. First, an illumination correction is performed on the green band retinal image. Next, the morphological closing and subtraction processing are applied to obtain the crude retinal vessel image. Then, the multi-scale line detection is used to fine the vessel image. Finally, the binary vasculature is extracted by the Otsu algorithm. In this paper, for improving the drawbacks of multi-scale line detection, only the line detectors at 4 scales are used. The experimental results show that the accuracy is 0.939 for DRIVE (digital retinal images for vessel extraction) retinal database, which is much better than other methods.

  13. The clinical impact of mean vessel size and solidity in breast carcinoma patients.

    Directory of Open Access Journals (Sweden)

    Lars Tore Gyland Mikalsen

    Full Text Available Angiogenesis quantification, through vessel counting or area estimation in the most vascular part of the tumour, has been found to be of prognostic value across a range of carcinomas, breast cancer included. We have applied computer image analysis to quantify vascular properties pertaining to size, shape and spatial distributions in photographed fields of CD34 stained sections. Aided by a pilot (98 cases, seven parameters were selected and validated on a separate set from 293 breast cancer patients. Two new prognostic markers were identified through continuous cox regression with endpoints breast cancer specific survival and distant disease free survival: The average size of the vessels as measured by their perimeter (p = 0.003 and 0.004, respectively, and the average complexity of the vessel shapes measured by their solidity (p = 0.004 and 0.004. The Hazard ratios for the corresponding median-dichotomized markers were 2.28 (p = 0.005 and 1.89 (p = 0.016 for the mean perimeter and 1.80 (p = 0.041 and 1.55 (p = 0.095 for the shape complexity. The markers were associated with poor histologic type, high grade, necrosis, HR negativity, inflammation, and p53 expression (vessel size only. Both markers were found to strongly influence the prognostic properties of vascular invasion (VI and disseminated tumour cells in the bone marrow. The latter being prognostic only in cases with large vessels (p = 0.004 and 0.043 or low complexity (p = 0.018 and 0.024, but not in the small or complex vessel groups (p>0.47. VI was significant in all groups, but showed greater hazard ratios for small and low complexity vessels (6.54-11.2 versus large and high complexity vessels (2.64-3.06. We find that not only the overall amount of produced vasculature in angiogenic hot-spots is of prognostic significance, but also the morphological appearance of the generated vessels, i.e. the size and shape of vessels in the studied hot spots.

  14. Use of commercial vessels in survey augmentation: the size-frequency distribution

    Directory of Open Access Journals (Sweden)

    Eric N. Powell

    2006-09-01

    Full Text Available The trend towards use of commercial vessels to enhance survey data requires assessment of the advantages and limitations of various options for their use. One application is to augment information on size-frequency distributions obtained in multispecies trawl surveys where stratum boundaries and sampling density are not optimal for all species. Analysis focused on ten recreationally and commercially important species: bluefish, butterfish, Loligo squid, weakfish, summer flounder, winter flounder, silver hake (whiting, black sea bass, striped bass, and scup (porgy. The commercial vessel took 59 tows in the sampled domain south of Long Island, New York and the survey vessel 18. Black sea bass, Loligo squid, and summer flounder demonstrated an onshore-offshore gradient such that smaller fish were caught disproportionately inshore and larger fish offshore. Butterfish, silver hake, and weakfish were characterized by a southwest-northeast gradient such that larger fish were caught disproportionately northeast of the southwestern-most sector. All sizes of scup, striped bass, and bluefish were caught predominately inshore. Winter flounder were caught predominately offshore. The commercial vessel was characterized by an increased frequency of large catches for most species. Consequently, patchiness was assayed to be higher by the commercial vessel in nearly all cases. The size-frequency distribution obtained by the survey vessel for six of the ten species, bluefish, butterfish, Loligo squid, summer flounder, weakfish, and silver hake, could not be obtained by chance from the size-frequency distribution obtained by the commercial vessel. The difference in sample density did not significantly influence the size-frequency distribution. Of the six species characterized by significant differences in size-frequency distribution between boats, all but one was patchy at the population level and all had one or more size classes so characterized. Although the

  15. Motion correction for passive radiation imaging of small vessels in ship-to-ship inspections

    Energy Technology Data Exchange (ETDEWEB)

    Ziock, K.P., E-mail: ziockk@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Boehnen, C.B.; Ernst, J.M.; Fabris, L. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Hayward, J.P. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Department of Nuclear Engineering, University of Tennessee, Knoxville, TN (United States); Karnowski, T.P.; Paquit, V.C.; Patlolla, D.R. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Trombino, D.G. [Lawrence Livermore National Laboratory, Livermore, CA (United States)

    2016-01-01

    Passive radiation detection remains one of the most acceptable means of ascertaining the presence of illicit nuclear materials. In maritime applications it is most effective against small to moderately sized vessels, where attenuation in the target vessel is of less concern. Unfortunately, imaging methods that can remove source confusion, localize a source, and avoid other systematic detection issues cannot be easily applied in ship-to-ship inspections because relative motion of the vessels blurs the results over many pixels, significantly reducing system sensitivity. This is particularly true for the smaller watercraft, where passive inspections are most valuable. We have developed a combined gamma-ray, stereo visible-light imaging system that addresses this problem. Data from the stereo imager are used to track the relative location and orientation of the target vessel in the field of view of a coded-aperture gamma-ray imager. Using this information, short-exposure gamma-ray images are projected onto the target vessel using simple tomographic back-projection techniques, revealing the location of any sources within the target. The complex autonomous tracking and image reconstruction system runs in real time on a 48-core workstation that deploys with the system.

  16. NMR blood vessel imaging method and apparatus

    International Nuclear Information System (INIS)

    Riederer, S.J.

    1988-01-01

    A high speed method of forming computed images of blood vessels based on measurements of characteristics of a body is described comprising the steps of: subjecting a predetermined body area containing blood vessels of interest to, successively, applications of a short repetition time (TR) NMR pulse sequence during the period of high blood velocity and then to corresponding applications during the period of low blood velocity for successive heart beat cycles; weighting the collected imaging data from each application of the NMR pulse sequence according to whether the data was acquired during the period of high blood velocity or a period of low blood velocity of the corresponding heart beat cycle; accumulating weighted imaging data from a plurality of NMR pulse sequences corresponding to high blood velocity periods and from a plurality of NMR pulse sequences corresponding to low blood velocity periods; subtracting the weighted imaging data corresponding to each specific phase encoding acquired during the high blood velocity periods from the weighted imaging data for the same phase encoding corresponding to low blood velocity periods in order to compute blood vessel imaging data; and forming an image of the blood vessels of interest from the blood vessel imaging data

  17. Coronary magnetic resonance imaging: visualization of the vessel lumen and the vessel wall and molecular imaging of arteriothrombosis

    International Nuclear Information System (INIS)

    Spuentrup, Elmar; Botnar, Rene M.

    2006-01-01

    Coronary magnetic resonance (MR) imaging has dramatically emerged over the last decade. Technical improvements have enabled reliable visualization of the proximal and midportion of the coronary artery tree for exclusion of significant coronary artery disease. However, current technical developments focus also on direct visualization of the diseased coronary vessel wall and imaging of coronary plaque because plaques without stenoses are typically more vulnerable with higher risk of plaque rupture. Plaque rupture with subsequent thrombosis and vessel occlusion is the main cause of myocardial infarction. Very recently, the first success of molecular imaging in the coronary arteries has been demonstrated using a fibrin-specific contrast agent for selective visualization of coronary thrombosis. This demonstrates in general the high potential of molecular MR imaging in the field of coronary artery disease. In this review, we will address recent technical advances in coronary MR imaging, including visualization of the lumen and the vessel wall and molecular imaging of coronary arteriothrombosis. First results of these new approaches will be discussed. (orig.)

  18. Neuroradiologic Characteristics of Primary Angiitis of the Central Nervous System According to the Affected Vessel Size.

    Science.gov (United States)

    Thaler, Christian; Kaufmann-Bühler, Ann-Katrin; Gansukh, Tserenchunt; Gansukh, Amarjargal; Schuster, Simon; Bachmann, Henrike; Thomalla, Götz; Magnus, Tim; Matschke, Jakob; Fiehler, Jens; Siemonsen, Susanne

    2017-09-05

    Magnetic resonance imaging (MRI) has an important impact in diagnosing primary angiitis of the central nervous system (PACNS). However, neuroradiologic findings may vary immensely, making an easy and definite diagnosis challenging. In this retrospective, single center study, we analyzed neuroradiologic findings of patients with PACNS diagnosed at our hospital between 2009 and 2014. Furthermore, we classified patients according to the affected vessel size and compared imaging characteristics between the subgroups. Thirty-three patients were included (mean age 43 [±15.3] years, 17 females) in this study. Patients with positive angiographic findings were classified as either medium or large vessel PACNS and presented more ischemic lesions (p effect. Twenty-five patients underwent brain biopsy. Patients with medium or large vessel PACNS were less likely to have positive biopsy results. It is essential to differentiate between small and medium/large vessel PACNS since results in MRI, digital subtraction angiography and brain biopsy may differ immensely. Since image quality of MR scanners improves gradually and brain biopsy may often be nonspecific or negative, our results emphasize the importance of MRI/MRA in the diagnosis process of PACNS.

  19. Roi Detection and Vessel Segmentation in Retinal Image

    Science.gov (United States)

    Sabaz, F.; Atila, U.

    2017-11-01

    Diabetes disrupts work by affecting the structure of the eye and afterwards leads to loss of vision. Depending on the stage of disease that called diabetic retinopathy, there are sudden loss of vision and blurred vision problems. Automated detection of vessels in retinal images is a useful study to diagnose eye diseases, disease classification and other clinical trials. The shape and structure of the vessels give information about the severity of the disease and the stage of the disease. Automatic and fast detection of vessels allows for a quick diagnosis of the disease and the treatment process to start shortly. ROI detection and vessel extraction methods for retinal image are mentioned in this study. It is shown that the Frangi filter used in image processing can be successfully used in detection and extraction of vessels.

  20. ROI DETECTION AND VESSEL SEGMENTATION IN RETINAL IMAGE

    Directory of Open Access Journals (Sweden)

    F. Sabaz

    2017-11-01

    Full Text Available Diabetes disrupts work by affecting the structure of the eye and afterwards leads to loss of vision. Depending on the stage of disease that called diabetic retinopathy, there are sudden loss of vision and blurred vision problems. Automated detection of vessels in retinal images is a useful study to diagnose eye diseases, disease classification and other clinical trials. The shape and structure of the vessels give information about the severity of the disease and the stage of the disease. Automatic and fast detection of vessels allows for a quick diagnosis of the disease and the treatment process to start shortly. ROI detection and vessel extraction methods for retinal image are mentioned in this study. It is shown that the Frangi filter used in image processing can be successfully used in detection and extraction of vessels.

  1. RAPID COMMUNICATION: Magnetic resonance imaging inside metallic vessels

    Science.gov (United States)

    Han, Hui; Balcom, Bruce J.

    2010-10-01

    We introduce magnetic resonance imaging (MRI) measurements inside metallic vessels. Until now, MRI has been unusable inside metallic vessels because of eddy currents in the walls. We have solved the problem and generated high quality images by employing a magnetic field gradient monitoring method. The ability to image within metal enclosures and structures means many new samples and systems are now amenable to MRI. Most importantly this study will form the basis of new MRI-compatible metallic pressure vessels, which will permit MRI of macroscopic systems at high pressure.

  2. MR angiography of the cerebral vessels with inflow-increased visualization by overcontiguous imaging and advanced processing

    International Nuclear Information System (INIS)

    McLachian, S.; Simon, H.E.; de Graaf, R.; Ho, A.M.; Ruccio, W.J.; Steidley, J.W.; Pradhan, R.B.

    1989-01-01

    The purpose of this study was to increase the visualization of cerebral vessels with MR angiography by using an inflow technique from transverse sections. Difficulties with visualization include the tortuous nature of the vessels and slow blood flow. The MR method is a transverse two-dimensional multiple single-section sequence with a velocity-compensated gradient echo and presaturation. A S15 imager with 10-mTm gradients and a prototype angiographic package is used. Overcontiguous acquisition yields smaller effective center-to-center sections. Interpolation is used to generate interleaved plane projections. A combination of image parameter swill reduce the level of the stationary tissue relative to the flowing blood. For vessels that are not perpendicular to the section, overlapping the sections by 25%--33% is shown to reduce the staircase appearance without affecting the apparent size of the vessels. Interpolation of the MR images will further reduce this artifact, giving the vessels a smooth structure. MR angiography of the brain performed with an inflow technique allows the visualization of vessels in the brain even if the vessels follow tortuous paths. Presaturation and user-defined regions of interest can be used for ease of interpretation

  3. Imaging of pediatric great vessel stents : Computed tomography or magnetic resonance imaging?

    NARCIS (Netherlands)

    den Harder, A M; Suchá, D; van Hamersvelt, R W; Budde, R P J; de Jong, P A; Schilham, A M R; Bos, C; Breur, J M P J; Leiner, T

    2017-01-01

    BACKGROUND: Complications might occur after great vessel stent implantation in children. Therefore follow-up using imaging is warranted. PURPOSE: To determine the optimal imaging modality for the assessment of stents used to treat great vessel obstructions in children. MATERIAL AND METHODS: Five

  4. Adaptable three-dimensional Monte Carlo modeling of imaged blood vessels in skin

    Science.gov (United States)

    Pfefer, T. Joshua; Barton, Jennifer K.; Chan, Eric K.; Ducros, Mathieu G.; Sorg, Brian S.; Milner, Thomas E.; Nelson, J. Stuart; Welch, Ashley J.

    1997-06-01

    In order to reach a higher level of accuracy in simulation of port wine stain treatment, we propose to discard the typical layered geometry and cylindrical blood vessel assumptions made in optical models and use imaging techniques to define actual tissue geometry. Two main additions to the typical 3D, weighted photon, variable step size Monte Carlo routine were necessary to achieve this goal. First, optical low coherence reflectometry (OLCR) images of rat skin were used to specify a 3D material array, with each entry assigned a label to represent the type of tissue in that particular voxel. Second, the Monte Carlo algorithm was altered so that when a photon crosses into a new voxel, the remaining path length is recalculated using the new optical properties, as specified by the material array. The model has shown good agreement with data from the literature. Monte Carlo simulations using OLCR images of asymmetrically curved blood vessels show various effects such as shading, scattering-induced peaks at vessel surfaces, and directionality-induced gradients in energy deposition. In conclusion, this augmentation of the Monte Carlo method can accurately simulate light transport for a wide variety of nonhomogeneous tissue geometries.

  5. Standard heart and vessel size on plain films of normal children

    International Nuclear Information System (INIS)

    Stoever, B.

    1986-01-01

    Standards of heart size, i.e. heart diameters and heart volume of normal children aged 4-15 years were obtained. In all cases requiring exact heart size determination, heart volume calculation is mandatory in children as well as in adults. Statistical work to date has provided precise calculation of heart volume plain films in the upright position. Additional plain films in prone position are unnecessary because no evident orthostatic influence on heart volume in children can be found. Percentiles of normal heart volume related to body weight representing the best correlation to the individual data are given as well as percentiles related to age. Furthermore ratios of normal vessel size to the height of the 8sup(th) thoracic vertebral body, measured on the same plain film, are given. In addition the ratio of upper to lower lung vessel size is calculated. These ratios are useful criteria in estimating normal vessel size and also in cases with increased pulmonary venous pressure. (orig.) [de

  6. Intracranial vessel wall imaging at 7.0 tesla MRI

    NARCIS (Netherlands)

    van der Kolk, A.G.

    2014-01-01

    Intracranial atherosclerosis is one of the main causes of ischemic stroke. Current conventional imaging techniques assessing intracranial arterial disease in vivo only visualize the vessel wall lumen instead of the pathological vessel wall itself. Therefore, not much is known about the imaging

  7. Vessel Sampling and Blood Flow Velocity Distribution With Vessel Diameter for Characterizing the Human Bulbar Conjunctival Microvasculature.

    Science.gov (United States)

    Wang, Liang; Yuan, Jin; Jiang, Hong; Yan, Wentao; Cintrón-Colón, Hector R; Perez, Victor L; DeBuc, Delia C; Feuer, William J; Wang, Jianhua

    2016-03-01

    This study determined (1) how many vessels (i.e., the vessel sampling) are needed to reliably characterize the bulbar conjunctival microvasculature and (2) if characteristic information can be obtained from the distribution histogram of the blood flow velocity and vessel diameter. Functional slitlamp biomicroscope was used to image hundreds of venules per subject. The bulbar conjunctiva in five healthy human subjects was imaged on six different locations in the temporal bulbar conjunctiva. The histograms of the diameter and velocity were plotted to examine whether the distribution was normal. Standard errors were calculated from the standard deviation and vessel sample size. The ratio of the standard error of the mean over the population mean was used to determine the sample size cutoff. The velocity was plotted as a function of the vessel diameter to display the distribution of the diameter and velocity. The results showed that the sampling size was approximately 15 vessels, which generated a standard error equivalent to 15% of the population mean from the total vessel population. The distributions of the diameter and velocity were not only unimodal, but also somewhat positively skewed and not normal. The blood flow velocity was related to the vessel diameter (r=0.23, Psampling size of the vessels and the distribution histogram of the blood flow velocity and vessel diameter, which may lead to a better understanding of the human microvascular system of the bulbar conjunctiva.

  8. Large vessel imaging using cosmic-ray muons

    International Nuclear Information System (INIS)

    Jenneson, P.M.

    2004-01-01

    Cosmic-ray muons are assessed for their practical use in the tomographic imaging of the internal composition of large vessels over 2 m in diameter. The technique is based on the attenuation and scattering of cosmic-ray muons passing through a vessel and has advantages over photon-based methods of tomography that it is extendable to object containing high-density materials over many tens of metres. The main disadvantage is the length of time required to produce images of sufficient resolution and hence cosmic ray muon tomography will be most suited to the imaging of large structures whose internal composition is effectively static for the duration of the imaging period. Simulation and theoretical results are presented here which demonstrate the feasibility of cosmic ray muon tomography

  9. Proximal Occlusion of Medium-Sized Vessels with the Penumbra Occlusion Device: A Study of Safety and Efficacy

    Energy Technology Data Exchange (ETDEWEB)

    Jambon, E.; Petitpierre, F. [Pellegrin Hospital, Department of Radiology (France); Brizzi, V.; Dubuisson, V. [Pellegrin Hospital, Department of Surgery (France); Bras, Y. Le; Grenier, N.; Cornelis, F., E-mail: cornelisfrancois@gmail.com [Pellegrin Hospital, Department of Radiology (France)

    2017-02-15

    PurposeTo retrospectively investigate the safety and efficacy of hybrid proximal coiling of various medium-sized vessels (4 to 8 mm) using the Penumbra Occlusion Device (POD).Materials and MethodsFrom October 2014 to February 2016, 37 proximal embolizations were performed with PODs in 36 patients (mean age: 50.8, range: 10–86; 29 male, 7 female). Vessel occlusions were achieved under fluoroscopic guidance using a 2.7 French microcatheter. Among the 36 vessels targeted, 16 were splenic arteries, 11 renal arteries, 4 mesenteric arteries, 3 arteriovenous fistulae, 1 iliac artery, and 1 gonadal vein. Intermittent follow-up angiography was performed to assess the flow for final occlusion. Outcomes and complications were assessed by clinical and/or imaging follow-up.ResultsTo produce proximal occlusion of the intended vessels, the POD was used alone in 19 embolizations (51.4 %). In 12 procedures (32.4 %), POD was used as a coil constrainer to secure the coil construct. In 6 procedures (16.2 %), additional embolic devices were used to achieve vessel occlusion after initial POD deployment. After a mean follow-up of 3.2 months, no POD migration was observed but two complications occurred (5.4 %): one post embolic syndrome and one extensive infarction with splenic abscess.ConclusionThe POD system allows safe and effective proximal embolization of medium-sized vessels in a variety of clinical settings.

  10. Automatic segmentation of blood vessels from retinal fundus images ...

    Indian Academy of Sciences (India)

    The retinal blood vessels were segmented through color space conversion and color channel .... Retinal blood vessel segmentation was also attempted through multi-scale operators. A few works in this ... fundus camera at 35 degrees field of view. The image ... vessel segmentation is available from two human observers.

  11. Visual tritium imaging of In-Vessel surfaces

    International Nuclear Information System (INIS)

    Gentile, C. A.; Zweben, S. J.; Skinner, C. H.; Young, K. M.; Langish, S. W.; Nishi, M. F.; Shu, W. M.; Parker, J.; Isobe, K.

    2000-01-01

    A imaging detector has been developed for the purpose of providing a non-destructive, real time method of determining tritium concentrations on the surface of internal TFTR vacuum vessel components. The detector employs a green phosphor screen (P31, zinc sulfide: copper) with a wave length peak of 530 nm, a charge-coupled device (CCD) camera linked to a computer, and a detection chamber for inserting components recovered from the vacuum vessel. This detector is capable of determining tritium concentrations on the surfaces. The detector provides a method of imaging tritium deposition on the surfaces in a fairly rapid fashion

  12. Visual tritium imaging of in-vessel surfaces

    International Nuclear Information System (INIS)

    Gentile, C.A.; Zweben, S.J.; Skinner, C.H.; Young, K.M.; Langish, S.W.; Nishi, M.F.; Shu, W.M.; Parker, J.; Isobe, K.

    2000-01-01

    An imaging detector has been developed for the purpose of providing a non-destructive, real time method of determining tritium concentrations on the surface of internal TFTR vacuum vessel components. The detector employs a green phosphor screen (P31, zinc sulfide: copper) with a wave length peak of 530 nm, a charge-coupled device (CCD) camera linked to a computer, and a detection chamber for inserting components recovered from the vacuum vessel. This detector is capable of determining tritium concentrations on the surfaces. The detector provides a method of imaging tritium deposition on the surfaces in a fairly rapid fashion

  13. Fracture capacity of HFIR vessel with random crack size and toughness

    International Nuclear Information System (INIS)

    Chang, S.J.

    1994-01-01

    The probability of fracture versus a range of applied hoop stresses along the High Flux Isotope Reactor vessel is obtained as an estimate of its fracture capacity. Both the crack size and the fracture toughness are assumed to be random variables and subject to assumed distribution functions. Possible hoop stress is based on the numerical solution of the vessel response by applying a point pressure-pulse at the center of the fluid volume within the vessel. Both the fluid-structure interaction and radiation embrittlement are taken into consideration. Elastic fracture mechanics is used throughout the analysis. The probability function of fracture for a single crack due to either a variable crack depth or a variable toughness is derived. Both the variable crack size and the variable toughness are assumed to follow known distributions. The probability of vessel fracture with multiple number of cracks is then obtained as a function of the applied hoop stress. The probability of fracture function is, then, extended to include different levels of confidence and variability. It, therefore, enables one to estimate the high confidence and low probability fracture capacity of the reactor vessel under a range of accident loading conditions

  14. Pulmonary artery pulsatility and effect on vessel diameter assessment in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Shariat, Masoud; Schantz, Daryl; Yoo, Shi-Joon; Wintersperger, Bernd J.; Seed, Mike; Alnafisi, Bahiyah; Chu, Leysia; MacGowan, Christopher K.; Amerom, Joshua van; Grosse-Wortmann, Lars

    2014-01-01

    Background: Information about thoracic vascular sizes can crucially affect clinical decision-making in cardiovascular disease. A variety of imaging techniques such as catheter angiography, contrast enhanced computed tomography (CT) and cardiac magnetic resonance imaging (CMR) are routinely used to measure vascular diameters. Traditionally, CMR black blood sequences were the main anatomical tool for visualization of vascular anatomy and still are in many centers. More recently, the vessel diameters are measured on multiplanar reconstructions derived from static magnetic resonance angiography (MRA). This study was performed to investigate the variation of vessel diameter measurements on different CMR techniques with respect to their data acquisition scheme. Methods: We recruited two groups of patients for this prospective study. One group included patients with repaired tetralogy of Fallot (TOF), with at least moderate pulmonary insufficiency and another group of patients who underwent CMR as part of a diagnostic work-up for arrhythmogenic right ventricular cardiomyopathy (ARVC). Additional images of the right pulmonary artery (RPA) were acquired in the double inversion recovery (DIR) black blood, cine steady state free precession (SSFP) and MRA. All images were reviewed by two CMR trained readers using the electronic caliper provided within the picture archiving and communication system package. The maximum diameter of each artery was recorded in millimeters with up to one decimal point. Paired t-tests and Bland–Altman plots were used for comparison of measurements between different sequences. Results: A total of 52 patients were recruited for this study, 26 patients in the TOF group (15 males, age 12.55 ± 2.9) and 26 patients in the ARVC group (15 males, age 15.6 ± 2.3). In both groups, the RPA sizes were not significantly different between the DIR images and diastolic cine SSFP (p > 0.05). Measurements on DIR were significantly smaller than those made on

  15. Pulmonary artery pulsatility and effect on vessel diameter assessment in magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Shariat, Masoud, E-mail: masoudshariat@gmail.com [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Schantz, Daryl, E-mail: daryl.schantz@gmail.com [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Yoo, Shi-Joon, E-mail: shi-joon.yoo@sickkids.ca [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Wintersperger, Bernd J., E-mail: bernd.wintersperger@uhn.ca [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Seed, Mike, E-mail: mike.seed@sickkids.ca [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Department of Cardiology, Hospital for Sick Children, Toronto, Ontario (Canada); Alnafisi, Bahiyah, E-mail: bahiyah.alnafisi@uhn.ca [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Chu, Leysia, E-mail: leysia_99@yahoo.com [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); MacGowan, Christopher K., E-mail: christopher.macgowan@sickkids.ca [Department of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Ontario (Canada); Amerom, Joshua van, E-mail: Joshu.vanamerom@sickkids.ca [Department of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Ontario (Canada); Grosse-Wortmann, Lars, E-mail: lars.grosse-wortmann@sickkids.ca [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Department of Cardiology, Hospital for Sick Children, Toronto, Ontario (Canada)

    2014-02-15

    Background: Information about thoracic vascular sizes can crucially affect clinical decision-making in cardiovascular disease. A variety of imaging techniques such as catheter angiography, contrast enhanced computed tomography (CT) and cardiac magnetic resonance imaging (CMR) are routinely used to measure vascular diameters. Traditionally, CMR black blood sequences were the main anatomical tool for visualization of vascular anatomy and still are in many centers. More recently, the vessel diameters are measured on multiplanar reconstructions derived from static magnetic resonance angiography (MRA). This study was performed to investigate the variation of vessel diameter measurements on different CMR techniques with respect to their data acquisition scheme. Methods: We recruited two groups of patients for this prospective study. One group included patients with repaired tetralogy of Fallot (TOF), with at least moderate pulmonary insufficiency and another group of patients who underwent CMR as part of a diagnostic work-up for arrhythmogenic right ventricular cardiomyopathy (ARVC). Additional images of the right pulmonary artery (RPA) were acquired in the double inversion recovery (DIR) black blood, cine steady state free precession (SSFP) and MRA. All images were reviewed by two CMR trained readers using the electronic caliper provided within the picture archiving and communication system package. The maximum diameter of each artery was recorded in millimeters with up to one decimal point. Paired t-tests and Bland–Altman plots were used for comparison of measurements between different sequences. Results: A total of 52 patients were recruited for this study, 26 patients in the TOF group (15 males, age 12.55 ± 2.9) and 26 patients in the ARVC group (15 males, age 15.6 ± 2.3). In both groups, the RPA sizes were not significantly different between the DIR images and diastolic cine SSFP (p > 0.05). Measurements on DIR were significantly smaller than those made on

  16. IMPROVING THE QUALITY OF NEAR-INFRARED IMAGING OF IN VIVOBLOOD VESSELS USING IMAGE FUSION METHODS

    DEFF Research Database (Denmark)

    Jensen, Andreas Kryger; Savarimuthu, Thiusius Rajeeth; Sørensen, Anders Stengaard

    2009-01-01

    We investigate methods for improving the visual quality of in vivo images of blood vessels in the human forearm. Using a near-infrared light source and a dual CCD chip camera system capable of capturing images at visual and nearinfrared spectra, we evaluate three fusion methods in terms...... of their capability of enhancing the blood vessels while preserving the spectral signature of the original color image. Furthermore, we investigate a possibility of removing hair in the images using a fusion rule based on the "a trous" stationary wavelet decomposition. The method with the best overall performance...... with both speed and quality in mind is the Intensity Injection method. Using the developed system and the methods presented in this article, it is possible to create images of high visual quality with highly emphasized blood vessels....

  17. Detection of Blood Vessels in Color Fundus Images using a Local Radon Transform

    Directory of Open Access Journals (Sweden)

    Reza Pourreza

    2010-09-01

    Full Text Available Introduction: This paper addresses a method for automatic detection of blood vessels in color fundus images which utilizes two main tools: image partitioning and local Radon transform. Material and Methods: The input images are firstly divided into overlapping windows and then the Radon transform is applied to each. The maximum of the Radon transform in each window corresponds to the probable available sub-vessel. To verify the detected sub-vessel, the maximum is compared with a predefined threshold. The verified sub-vessels are reconstructed using the Radon transform information. All detected and reconstructed sub-vessels are finally combined to make the final vessel tree. Results: The algorithm’s performance was evaluated numerically by applying it to 40 images of DRIVE database, a standard retinal image database. The vessels were extracted manually by two physicians. This database was used to test and compare the available and proposed algorithms for vessel detection in color fundus images. By comparing the output of the algorithm with the manual results, the two parameters TPR and FPR were calculated for each image and the average of TPRs and FPRs were used to plot the ROC curve. Discussion and Conclusion: Comparison of the ROC curve of this algorithm with other algorithms demonstrated the high achieved accuracy. Beside the high accuracy, the Radon transform which is integral-based makes the algorithm robust against noise.

  18. Study on external reactor vessel cooling capacity for advanced large size PWR

    International Nuclear Information System (INIS)

    Jin Di; Liu Xiaojing; Cheng Xu; Li Fei

    2014-01-01

    External reactor vessel cooling (ERVC) is widely adopted as a part of in- vessel retention (IVR) in severe accident management strategies. In this paper, some flow parameters and boundary conditions, eg., inlet and outlet area, water inlet temperature, heating power of the lower head, the annular gap size at the position of the lower head and flooding water level, were considered to qualitatively study the effect of them on natural circulation capacity of the external reactor vessel cooling for an advanced large size PWR by using RELAP5 code. And the calculation results provide some basis of analysis for the structure design and the following transient response behavior of the system. (authors)

  19. Quantification of common carotid artery and descending aorta vessel wall thickness from MR vessel wall imaging using a fully automated processing pipeline.

    Science.gov (United States)

    Gao, Shan; van 't Klooster, Ronald; Brandts, Anne; Roes, Stijntje D; Alizadeh Dehnavi, Reza; de Roos, Albert; Westenberg, Jos J M; van der Geest, Rob J

    2017-01-01

    To develop and evaluate a method that can fully automatically identify the vessel wall boundaries and quantify the wall thickness for both common carotid artery (CCA) and descending aorta (DAO) from axial magnetic resonance (MR) images. 3T MRI data acquired with T 1 -weighted gradient-echo black-blood imaging sequence from carotid (39 subjects) and aorta (39 subjects) were used to develop and test the algorithm. The vessel wall segmentation was achieved by respectively fitting a 3D cylindrical B-spline surface to the boundaries of lumen and outer wall. The tube-fitting was based on the edge detection performed on the signal intensity (SI) profile along the surface normal. To achieve a fully automated process, Hough Transform (HT) was developed to estimate the lumen centerline and radii for the target vessel. Using the outputs of HT, a tube model for lumen segmentation was initialized and deformed to fit the image data. Finally, lumen segmentation was dilated to initiate the adaptation procedure of outer wall tube. The algorithm was validated by determining: 1) its performance against manual tracing; 2) its interscan reproducibility in quantifying vessel wall thickness (VWT); 3) its capability of detecting VWT difference in hypertensive patients compared with healthy controls. Statistical analysis including Bland-Altman analysis, t-test, and sample size calculation were performed for the purpose of algorithm evaluation. The mean distance between the manual and automatically detected lumen/outer wall contours was 0.00 ± 0.23/0.09 ± 0.21 mm for CCA and 0.12 ± 0.24/0.14 ± 0.35 mm for DAO. No significant difference was observed between the interscan VWT assessment using automated segmentation for both CCA (P = 0.19) and DAO (P = 0.94). Both manual and automated segmentation detected significantly higher carotid (P = 0.016 and P = 0.005) and aortic (P < 0.001 and P = 0.021) wall thickness in the hypertensive patients. A reliable and reproducible pipeline for fully

  20. Detecting culprit vessel of coronary artery disease with SPECT 99Tcm-MIBI myocardial imaging

    International Nuclear Information System (INIS)

    Luan Zhaosheng; Zhou Wen; Peng Yong; Su Yuwen; Tian Jianhe; Gai lue; Sun Zhijun

    2002-01-01

    Objective: To assess the value of detecting culprit vessel of coronary artery disease (CAD) with SPECT 99 Tc m -MIBI myocardial imaging. Methods: Forty-six patients with CAD were studied. Every patients had multiple-vessel lesion showed by coronary arteriography and was treated by revascularization as percutaneous transluminal angioplasty (PTCA), coronary artery bypass graft (CABG) or laser holing. Exercise (EX), rest (RE) and intravenous infusion of nitroglycerine (NTG) SPECT 99 Tc m -MIBI myocardial imagings were performed before revascularization. Exercise and rest images revealed the myocardial ischemia. NTG images revealed myocardial viability. Culprit vessels were detected according to the defects showed by above mentioned images. The veracity of detected culprit vessels was tested with the outcome of the reperfusion therapy. Results: In this group, the coronary arteriography revealed 107 lesioned coronary arteries. Myocardial imaging detected 46 culprit vessels including 23 left anterior descending (LAD), 19 left circumflex coronary artery (LCX) and 4 right coronary artery (RCA). All 46 culprit vessels underwent revascularization and had nice outcome. The veracity of 99 Tc m -MIBI myocardial imaging detected culprit vessels was high according to patients' outcome. Conclusion: Exercise, rest and NTG 99 Tc m -MIBI myocardial imaging is a great method for detecting culprit vessels in multivessel coronary disease

  1. Fibre optic confocal imaging (FOCI) of keratinocytes, blood vessels and nerves in hairless mouse skin in vivo

    Science.gov (United States)

    BUSSAU, L. J.; VO, L. T.; DELANEY, P. M.; PAPWORTH, G. D.; BARKLA, D. H.; KING, R. G.

    1998-01-01

    Fibre optic confocal imaging (FOCI) enabled subsurface fluorescence microscopy of the skin of hairless mice in vivo. Application of acridine orange enabled imaging of the layers of the epidermis. The corneocytes of the stratum corneum, the keratinocytes in the basal layers and redundant hair follicles were visualised at depths greater than 100 μm. Cellular and nuclear membranes of keratinocytes of the skin were visualised by the use of acridine orange and DIOC5(3). Imaging of the skin after injection of FITC-dextran revealed an extensive network of blood vessels with a size range up to 20 μm. Blood cells could be seen moving through dermal vessels and the blood circulation through the dermal vascular bed was video-taped. The fluorescent dye 4-di-2-ASP showed the presence of nerves fibres around the hair follicles and subsurface blood vessels. Comparison was made between images obtained in vivo using FOCI and in vitro scanning electron microscopy and conventional histology. FOCI offers the potential to study dynamic events in vivo, such as blood flow, skin growth, nerve regeneration and many pathological processes, in ways which have not previously been possible. PMID:9643419

  2. Vessel Enhancement and Segmentation of 4D CT Lung Image Using Stick Tensor Voting

    Science.gov (United States)

    Cong, Tan; Hao, Yang; Jingli, Shi; Xuan, Yang

    2016-12-01

    Vessel enhancement and segmentation plays a significant role in medical image analysis. This paper proposes a novel vessel enhancement and segmentation method for 4D CT lung image using stick tensor voting algorithm, which focuses on addressing the vessel distortion issue of vessel enhancement diffusion (VED) method. Furthermore, the enhanced results are easily segmented using level-set segmentation. In our method, firstly, vessels are filtered using Frangi's filter to reduce intrapulmonary noises and extract rough blood vessels. Secondly, stick tensor voting algorithm is employed to estimate the correct direction along the vessel. Then the estimated direction along the vessel is used as the anisotropic diffusion direction of vessel in VED algorithm, which makes the intensity diffusion of points locating at the vessel wall be consistent with the directions of vessels and enhance the tubular features of vessels. Finally, vessels can be extracted from the enhanced image by applying level-set segmentation method. A number of experiments results show that our method outperforms traditional VED method in vessel enhancement and results in satisfied segmented vessels.

  3. The value of ultrasonographic examination in the evaluation of liver size and intrahepatic vessels

    International Nuclear Information System (INIS)

    Narojek, T.

    1995-01-01

    The objective of the investigations was to comparatively evaluate the size and shape of the liver on the basis of x-ray and ultrasonographic examinations and to estimate the liver parenchyma and intrahepatic vessels on the basis of ultrasonographic examinations. The studies were done on 64 dogs and 13 cats of different breed and sex, aged from 1 day to 18 years. The ultrasonographic examinations were done with the use of Bruel and Kjaer apparatus type 1849 and Concept 2000 by Dynamic Imaging. In 64 animals the ultrasonographic image of the liver was normal. In 7 cases an enlargement of the liver without any changes in the liver parenchyma was noted. An enlargement of intrahepatic veins was found in 8 cases (4 with circulatory insufficiency, 2 with ascites). The assessment of the size and shape of the liver done on that basis of ultrasound examinations agreed with that based on x-ray examinations. The ultrasonic examinations also allowed the evaluation of the liver parenchyma and intrahepatic veins. (author). 9 refs, figs, 3 tabs

  4. Estimation of center line and diameter of brain blood vessel using three-dimensional blood vessel matching method with head three-dimensional CTA image

    International Nuclear Information System (INIS)

    Maekawa, Masashi; Shinohara, Toshihiro; Nakayama, Masato; Nakasako, Noboru

    2010-01-01

    To support and automate the brain blood vessel disease diagnosis, a novel method to obtain the center line and the diameter of a blood vessel is proposed with a three-dimensional head computed tomographic angiography (CTA) image. Although the line thinning processing with distance transform or gray information is generally used to obtain the blood vessel center line, this method is not essentially one to obtain the center line and tends to yield extra lines depending on CTA images. In this study, the center line of the blood vessel is obtained by tracing the vessel. The blood vessel is traced by sequentially estimating the center point and direction of the blood vessel. The center point and direction of the blood vessel are estimated by taking the correlation between the blood vessel and a solid model of the blood vessel that is designed by considering noise influence. In addition, the vessel diameter is also estimated by correlating the blood vessel and the blood vessel model of which the diameter is variable. The validity of the proposed method is confirmed by experimentally applied the proposed method to an actual three-dimensional head CTA image. (author)

  5. Synthesis and characterization of Gadolinium-Lectin conjugates as selective blood-vessel contrast agents for magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Pashkunova-Martic, I.

    2004-11-01

    Molecular imaging without use of ionizing radiation has recently been developed for both magnetic resonance and ultrasound imaging (MRI, US) and is expected to play a major future role in diagnosis and monitoring of tumours. In MRI, targeted nanoparticle contrast media (CM) with high relaxivities are required in order to obtain adequate signal-to-noise ratios, due to the low number of target sites. The size, charge and chemical constitution of the targeted nanoparticle CM are expected to influence nanoparticle interactions with cells and tissue elements significantly, and hence the targeting, the accumulation and dwell time at the targeted site, and the type and rate of clearance of the nanoparticles. The work reported here aims to characterise and optimise these parameters in mouse and human models, using nanoparticles targeted to a major carbohydrate determinant of the endothelial cell surface which is present in all blood vessels. Specific binding to the endothelium was demonstrated in both living and chemically fixed human vessels and in mice. Long-standing spin-echo and FLASH-3D images were obtained in the vasculature of living mice, in strong contrast to the rapid renal clearance of gadolinium-DTPA chelates which are widely used in the clinic. Nanoparticle size was found to be a major determinant of the biological response, and our data indicate that an optimal nanoparticle size lies between 50-100 nm diameter. We expect that hyperpermeable vessels present in tumours will permit targeting of optimised nanoparticles to the tumour cells, permitting MRI monitoring of the tumour. (author)

  6. Blood vessel classification into arteries and veins in retinal images

    Science.gov (United States)

    Kondermann, Claudia; Kondermann, Daniel; Yan, Michelle

    2007-03-01

    The prevalence of diabetes is expected to increase dramatically in coming years; already today it accounts for a major proportion of the health care budget in many countries. Diabetic Retinopathy (DR), a micro vascular complication very often seen in diabetes patients, is the most common cause of visual loss in working age population of developed countries today. Since the possibility of slowing or even stopping the progress of this disease depends on the early detection of DR, an automatic analysis of fundus images would be of great help to the ophthalmologist due to the small size of the symptoms and the large number of patients. An important symptom for DR are abnormally wide veins leading to an unusually low ratio of the average diameter of arteries to veins (AVR). There are also other diseases like high blood pressure or diseases of the pancreas with one symptom being an abnormal AVR value. To determine it, a classification of vessels as arteries or veins is indispensable. As to our knowledge despite the importance there have only been two approaches to vessel classification yet. Therefore we propose an improved method. We compare two feature extraction methods and two classification methods based on support vector machines and neural networks. Given a hand-segmentation of vessels our approach achieves 95.32% correctly classified vessel pixels. This value decreases by 10% on average, if the result of a segmentation algorithm is used as basis for the classification.

  7. The Multiscale Bowler-Hat Transform for Vessel Enhancement in 3D Biomedical Images

    OpenAIRE

    Sazak, Cigdem; Nelson, Carl J.; Obara, Boguslaw

    2018-01-01

    Enhancement and detection of 3D vessel-like structures has long been an open problem as most existing image processing methods fail in many aspects, including a lack of uniform enhancement between vessels of different radii and a lack of enhancement at the junctions. Here, we propose a method based on mathematical morphology to enhance 3D vessel-like structures in biomedical images. The proposed method, 3D bowler-hat transform, combines sphere and line structuring elements to enhance vessel-l...

  8. A thresholding based technique to extract retinal blood vessels from fundus images

    Directory of Open Access Journals (Sweden)

    Jyotiprava Dash

    2017-12-01

    Full Text Available Retinal imaging has become the significant tool among all the medical imaging technology, due to its capability to extract many data which is linked to various eye diseases. So, the accurate extraction of blood vessel is necessary that helps the eye care specialists and ophthalmologist to identify the diseases at the early stages. In this paper, we have proposed a computerized technique for extraction of blood vessels from fundus images. The process is conducted in three phases: (i pre-processing where the image is enhanced using contrast limited adaptive histogram equalization and median filter, (ii segmentation using mean-C thresholding to extract retinal blood vessels, (iii post-processing where morphological cleaning operation is used to remove isolated pixels. The performance of the proposed method is tested on and experimental results show that our method achieve an accuracies of 0.955 and 0.954 on Digital retinal images for vessel extraction (DRIVE and Child heart and health study in England (CHASE_DB1 databases respectively.

  9. Electroerosion cutting of low-sized templets from WWER-1000 type reactor vessel

    International Nuclear Information System (INIS)

    Neklyudov, I.M.; Ozhigov, L.S.; Gozhenko, S.V.

    2012-01-01

    The article presents the results of developed method of electroerosion cutting of low-sized templets for the reactor vessel metal composition and structure control in laboratory environment. The article describes the equipment for the remote electroerosive cutting of templets from WWER-1000 type reactor vessel by rigid electrode. The testing results are also shown.

  10. Automated retinal vessel type classification in color fundus images

    Science.gov (United States)

    Yu, H.; Barriga, S.; Agurto, C.; Nemeth, S.; Bauman, W.; Soliz, P.

    2013-02-01

    Automated retinal vessel type classification is an essential first step toward machine-based quantitative measurement of various vessel topological parameters and identifying vessel abnormalities and alternations in cardiovascular disease risk analysis. This paper presents a new and accurate automatic artery and vein classification method developed for arteriolar-to-venular width ratio (AVR) and artery and vein tortuosity measurements in regions of interest (ROI) of 1.5 and 2.5 optic disc diameters from the disc center, respectively. This method includes illumination normalization, automatic optic disc detection and retinal vessel segmentation, feature extraction, and a partial least squares (PLS) classification. Normalized multi-color information, color variation, and multi-scale morphological features are extracted on each vessel segment. We trained the algorithm on a set of 51 color fundus images using manually marked arteries and veins. We tested the proposed method in a previously unseen test data set consisting of 42 images. We obtained an area under the ROC curve (AUC) of 93.7% in the ROI of AVR measurement and 91.5% of AUC in the ROI of tortuosity measurement. The proposed AV classification method has the potential to assist automatic cardiovascular disease early detection and risk analysis.

  11. Imaging of pediatric great vessel stents: Computed tomography or magnetic resonance imaging?

    Directory of Open Access Journals (Sweden)

    A M den Harder

    Full Text Available Complications might occur after great vessel stent implantation in children. Therefore follow-up using imaging is warranted.To determine the optimal imaging modality for the assessment of stents used to treat great vessel obstructions in children.Five different large vessel stents were evaluated in an in-vitro setting. All stents were expanded to the maximal vendor recommended diameter (20mm; n = 4 or 10mm; n = 1, placed in an anthropomorphic chest phantom and imaged with a 256-slice CT-scanner. MRI images were acquired at 1.5T using a multi-slice T2-weighted turbo spin echo, an RF-spoiled three-dimensional T1-weighted Fast Field Echo and a balanced turbo field echo 3D sequence. Two blinded observers assessed stent lumen visibility (measured diameter/true diameter *100% in the center and at the outlets of the stent. Reproducibility of diameter measurements was evaluated using the intraclass correlation coefficient for reliability and 95% limits of agreement for agreement analysis.Median stent lumen visibility was 88 (IQR 86-90% with CT for all stents at both the center and outlets. With MRI, the T2-weighted turbo spin echo sequence was preferred which resulted in 82 (78-84% stent lumen visibility. Interobserver reliability and agreement was good for both CT (ICC 0.997, mean difference -0.51 [-1.07-0.05] mm and MRI measurements (ICC 0.951, mean difference -0.05 [-2.52 --2.41] mm.Good in-stent lumen visibility was achievable in this in-vitro study with both CT and MRI in different great vessel stents. Overall reliability was good with clinical acceptable limits of agreement for both CT and MRI. However, common conditions such as in-stent stenosis and associated aneurysms were not tested in this in-vitro study, limiting the value of the in-vitro study.

  12. Imaging of pediatric great vessel stents: Computed tomography or magnetic resonance imaging?

    Science.gov (United States)

    den Harder, A M; Suchá, D; van Hamersvelt, R W; Budde, R P J; de Jong, P A; Schilham, A M R; Bos, C; Breur, J M P J; Leiner, T

    2017-01-01

    Complications might occur after great vessel stent implantation in children. Therefore follow-up using imaging is warranted. To determine the optimal imaging modality for the assessment of stents used to treat great vessel obstructions in children. Five different large vessel stents were evaluated in an in-vitro setting. All stents were expanded to the maximal vendor recommended diameter (20mm; n = 4 or 10mm; n = 1), placed in an anthropomorphic chest phantom and imaged with a 256-slice CT-scanner. MRI images were acquired at 1.5T using a multi-slice T2-weighted turbo spin echo, an RF-spoiled three-dimensional T1-weighted Fast Field Echo and a balanced turbo field echo 3D sequence. Two blinded observers assessed stent lumen visibility (measured diameter/true diameter *100%) in the center and at the outlets of the stent. Reproducibility of diameter measurements was evaluated using the intraclass correlation coefficient for reliability and 95% limits of agreement for agreement analysis. Median stent lumen visibility was 88 (IQR 86-90)% with CT for all stents at both the center and outlets. With MRI, the T2-weighted turbo spin echo sequence was preferred which resulted in 82 (78-84%) stent lumen visibility. Interobserver reliability and agreement was good for both CT (ICC 0.997, mean difference -0.51 [-1.07-0.05] mm) and MRI measurements (ICC 0.951, mean difference -0.05 [-2.52 --2.41] mm). Good in-stent lumen visibility was achievable in this in-vitro study with both CT and MRI in different great vessel stents. Overall reliability was good with clinical acceptable limits of agreement for both CT and MRI. However, common conditions such as in-stent stenosis and associated aneurysms were not tested in this in-vitro study, limiting the value of the in-vitro study.

  13. Automatic segmentation of blood vessels from retinal fundus images ...

    Indian Academy of Sciences (India)

    The retinal blood vessels were segmented through color space conversion and color channel extraction, image pre-processing, Gabor filtering, image postprocessing, feature construction through application of principal component analysis, k-means clustering and first level classification using Naïve–Bayes classification ...

  14. Automated classification and quantitative analysis of arterial and venous vessels in fundus images

    Science.gov (United States)

    Alam, Minhaj; Son, Taeyoon; Toslak, Devrim; Lim, Jennifer I.; Yao, Xincheng

    2018-02-01

    It is known that retinopathies may affect arteries and veins differently. Therefore, reliable differentiation of arteries and veins is essential for computer-aided analysis of fundus images. The purpose of this study is to validate one automated method for robust classification of arteries and veins (A-V) in digital fundus images. We combine optical density ratio (ODR) analysis and blood vessel tracking algorithm to classify arteries and veins. A matched filtering method is used to enhance retinal blood vessels. Bottom hat filtering and global thresholding are used to segment the vessel and skeleton individual blood vessels. The vessel tracking algorithm is used to locate the optic disk and to identify source nodes of blood vessels in optic disk area. Each node can be identified as vein or artery using ODR information. Using the source nodes as starting point, the whole vessel trace is then tracked and classified as vein or artery using vessel curvature and angle information. 50 color fundus images from diabetic retinopathy patients were used to test the algorithm. Sensitivity, specificity, and accuracy metrics were measured to assess the validity of the proposed classification method compared to ground truths created by two independent observers. The algorithm demonstrated 97.52% accuracy in identifying blood vessels as vein or artery. A quantitative analysis upon A-V classification showed that average A-V ratio of width for NPDR subjects with hypertension decreased significantly (43.13%).

  15. Automated vessel shadow segmentation of fovea-centered spectral-domain images from multiple OCT devices

    Science.gov (United States)

    Wu, Jing; Gerendas, Bianca S.; Waldstein, Sebastian M.; Simader, Christian; Schmidt-Erfurth, Ursula

    2014-03-01

    Spectral-domain Optical Coherence Tomography (SD-OCT) is a non-invasive modality for acquiring high reso- lution, three-dimensional (3D) cross sectional volumetric images of the retina and the subretinal layers. SD-OCT also allows the detailed imaging of retinal pathology, aiding clinicians in the diagnosis of sight degrading diseases such as age-related macular degeneration (AMD) and glaucoma.1 Disease diagnosis, assessment, and treatment requires a patient to undergo multiple OCT scans, possibly using different scanning devices, to accurately and precisely gauge disease activity, progression and treatment success. However, the use of OCT imaging devices from different vendors, combined with patient movement may result in poor scan spatial correlation, potentially leading to incorrect patient diagnosis or treatment analysis. Image registration can be used to precisely compare disease states by registering differing 3D scans to one another. In order to align 3D scans from different time- points and vendors using registration, landmarks are required, the most obvious being the retinal vasculature. Presented here is a fully automated cross-vendor method to acquire retina vessel locations for OCT registration from fovea centred 3D SD-OCT scans based on vessel shadows. Noise filtered OCT scans are flattened based on vendor retinal layer segmentation, to extract the retinal pigment epithelium (RPE) layer of the retina. Voxel based layer profile analysis and k-means clustering is used to extract candidate vessel shadow regions from the RPE layer. In conjunction, the extracted RPE layers are combined to generate a projection image featuring all candidate vessel shadows. Image processing methods for vessel segmentation of the OCT constructed projection image are then applied to optimize the accuracy of OCT vessel shadow segmentation through the removal of false positive shadow regions such as those caused by exudates and cysts. Validation of segmented vessel shadows uses

  16. Molecular magnetic resonance imaging of atherosclerotic vessel wall disease

    Energy Technology Data Exchange (ETDEWEB)

    Noerenberg, Dominik [Charite - University Medicine Berlin, Department of Radiology, Berlin (Germany); University of Munich - Grosshadern, Department of Clinical Radiology, Munich (Germany); Ebersberger, Hans U. [Heart Center Munich-Bogenhausen, Department of Cardiology and Intensive Care Medicine, Munich (Germany); Diederichs, Gerd; Hamm, Bernd [Charite - University Medicine Berlin, Department of Radiology, Berlin (Germany); Botnar, Rene M. [King' s College London, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom); Makowski, Marcus R. [Charite - University Medicine Berlin, Department of Radiology, Berlin (Germany); King' s College London, Division of Imaging Sciences and Biomedical Engineering, London (United Kingdom)

    2016-03-15

    Molecular imaging aims to improve the identification and characterization of pathological processes in vivo by visualizing the underlying biological mechanisms. Molecular imaging techniques are increasingly used to assess vascular inflammation, remodeling, cell migration, angioneogenesis and apoptosis. In cardiovascular diseases, molecular magnetic resonance imaging (MRI) offers new insights into the in vivo biology of pathological vessel wall processes of the coronary and carotid arteries and the aorta. This includes detection of early vascular changes preceding plaque development, visualization of unstable plaques and assessment of response to therapy. The current review focuses on recent developments in the field of molecular MRI to characterise different stages of atherosclerotic vessel wall disease. A variety of molecular MR-probes have been developed to improve the non-invasive detection and characterization of atherosclerotic plaques. Specifically targeted molecular probes allow for the visualization of key biological steps in the cascade leading to the development of arterial vessel wall lesions. Early detection of processes which lead to the development of atherosclerosis and the identification of vulnerable atherosclerotic plaques may enable the early assessment of response to therapy, improve therapy planning, foster the prevention of cardiovascular events and may open the door for the development of patient-specific treatment strategies. (orig.)

  17. Molecular magnetic resonance imaging of atherosclerotic vessel wall disease

    International Nuclear Information System (INIS)

    Noerenberg, Dominik; Ebersberger, Hans U.; Diederichs, Gerd; Hamm, Bernd; Botnar, Rene M.; Makowski, Marcus R.

    2016-01-01

    Molecular imaging aims to improve the identification and characterization of pathological processes in vivo by visualizing the underlying biological mechanisms. Molecular imaging techniques are increasingly used to assess vascular inflammation, remodeling, cell migration, angioneogenesis and apoptosis. In cardiovascular diseases, molecular magnetic resonance imaging (MRI) offers new insights into the in vivo biology of pathological vessel wall processes of the coronary and carotid arteries and the aorta. This includes detection of early vascular changes preceding plaque development, visualization of unstable plaques and assessment of response to therapy. The current review focuses on recent developments in the field of molecular MRI to characterise different stages of atherosclerotic vessel wall disease. A variety of molecular MR-probes have been developed to improve the non-invasive detection and characterization of atherosclerotic plaques. Specifically targeted molecular probes allow for the visualization of key biological steps in the cascade leading to the development of arterial vessel wall lesions. Early detection of processes which lead to the development of atherosclerosis and the identification of vulnerable atherosclerotic plaques may enable the early assessment of response to therapy, improve therapy planning, foster the prevention of cardiovascular events and may open the door for the development of patient-specific treatment strategies. (orig.)

  18. Reproducibility and variability of quantitative magnetic resonance imaging markers in cerebral small vessel disease

    NARCIS (Netherlands)

    De Guio, F. (François); Jouvent, E. (Eric); G.J. Biessels (Geert Jan); S.E. Black (Sandra); C. Brayne (Carol); C. Chen (Christopher); C. Cordonnier (Charlotte); H.F. de Leeuw (Frank); C. Kubisch (Christian); Doubal, F. (Fergus); Duering, M. (Marco); C. Dufouil (Carole); Duzel, E. (Emrah); F. Fazekas (Franz); V. Hachinski (Vladimir); M.K. Ikram (Kamran); J. Linn (Jennifer); P.M. Matthews (P.); B. Mazoyer (Bernard); Mok, V. (Vincent); B. Norrving (Bo); O'Brien, J.T. (John T.); Pantoni, L. (Leonardo); S. Ropele (Stefan); P.S. Sachdev (Perminder); R. Schmidt (Reinhold); S. Seshadri (Sudha); E.E. Smith (Eric); L.A. Sposato (Luciano A); B.C.M. Stephan; Swartz, R.H. (Richard H.); C. Tzourio (Christophe); M.A. van Buchem (Mark); A. van der Lugt (Aad); R.J. van Oostenbrugge (Robert); M.W. Vernooij (Meike); Viswanathan, A. (Anand); D.J. Werring (David); Wollenweber, F. (Frank); J.M. Wardlaw (J.); Chabriat, H. (Hugues)

    2016-01-01

    textabstractBrain imaging is essential for the diagnosis and characterization of cerebral small vessel disease. Several magnetic resonance imaging markers have therefore emerged, providing new information on the diagnosis, progression, and mechanisms of small vessel disease. Yet, the reproducibility

  19. Comparative analysis of methods for extracting vessel network on breast MRI images

    Science.gov (United States)

    Gaizer, Bence T.; Vassiou, Katerina G.; Lavdas, Eleftherios; Arvanitis, Dimitrios L.; Fezoulidis, Ioannis V.; Glotsos, Dimitris T.

    2017-11-01

    Digital processing of MRI images aims to provide an automatized diagnostic evaluation of regular health screenings. Cancerous lesions are proven to cause an alteration in the vessel structure of the diseased organ. Currently there are several methods used for extraction of the vessel network in order to quantify its properties. In this work MRI images (Signa HDx 3.0T, GE Healthcare, courtesy of University Hospital of Larissa) of 30 female breasts were subjected to three different vessel extraction algorithms to determine the location of their vascular network. The first method is an experiment to build a graph over known points of the vessel network; the second algorithm aims to determine the direction and diameter of vessels at these points; the third approach is a seed growing algorithm, spreading selection to neighbors of the known vessel pixels. The possibilities shown by the different methods were analyzed, and quantitative measurements were performed. The data provided by these measurements showed no clear correlation with the presence or malignancy of tumors, based on the radiological diagnosis of skilled physicians.

  20. On the Adequacy of API 521 Relief-Valve Sizing Method for Gas-Filled Pressure Vessels Exposed to Fire

    DEFF Research Database (Denmark)

    Andreasen, Anders; Nieto, Marcos Zan; Borroni, Filippo

    2018-01-01

    sense of security. Often the vessel wall will be weakened by high temperatures, before the PRV relieving pressure is reached. In this article, a multiparameter study has been performed taking into consideration various vessel sizes, design pressures (implicitly vessel wall thickness), vessel operating...

  1. Reproducibility and variability of quantitative magnetic resonance imaging markers in cerebral small vessel disease

    NARCIS (Netherlands)

    Guio, F. De; Jouvent, E.; Biessels, G.J.; Black, S.E.; Brayne, C.; Chen, C.; Cordonnier, C.; Leeuw, F.E. de; Dichgans, M.; Doubal, F.; Duering, M.; Dufouil, C.; Duzel, E.; Fazekas, F.; Hachinski, V.; Ikram, M.A.; Linn, J.; Matthews, P.M.; Mazoyer, B.; Mok, V.; Norrving, B.; O'Brien, J.T.; Pantoni, L.; Ropele, S.; Sachdev, P.; Schmidt, R.; Seshadri, S.; Smith, E.E.; Sposato, L.A.; Stephan, B.; Swartz, R.H.; Tzourio, C.; Buchem, M. van; Lugt, A. van der; Oostenbrugge, R.; Vernooij, M.W.; Viswanathan, A.; Werring, D.; Wollenweber, F.; Wardlaw, J.M.; Chabriat, H.

    2016-01-01

    Brain imaging is essential for the diagnosis and characterization of cerebral small vessel disease. Several magnetic resonance imaging markers have therefore emerged, providing new information on the diagnosis, progression, and mechanisms of small vessel disease. Yet, the reproducibility of these

  2. Development and validation of a custom made indocyanine green fluorescence lymphatic vessel imager

    Science.gov (United States)

    Pallotta, Olivia J.; van Zanten, Malou; McEwen, Mark; Burrow, Lynne; Beesley, Jack; Piller, Neil

    2015-06-01

    Lymphoedema is a chronic progressive condition often producing significant morbidity. An in-depth understanding of an individual's lymphatic architecture is valuable both in the understanding of underlying pathology and for targeting and tailoring treatment. Severe lower limb injuries resulting in extensive loss of soft tissue require transposition of a flap consisting of muscle and/or soft tissue to close the defect. These patients are at risk of lymphoedema and little is known about lymphatic regeneration within the flap. Indocyanine green (ICG), a water-soluble dye, has proven useful for the imaging of lymphatic vessels. When injected into superficial tissues it binds to plasma proteins in lymph. By exposing the dye to specific wavelengths of light, ICG fluoresces with near-infrared light. Skin is relatively transparent to ICG fluorescence, enabling the visualization and characterization of superficial lymphatic vessels. An ICG fluorescence lymphatic vessel imager was manufactured to excite ICG and visualize real-time fluorescence as it travels through the lymphatic vessels. Animal studies showed successful ICG excitation and detection using this imager. Clinically, the imager has assisted researchers to visualize otherwise hidden superficial lymphatic pathways in patients postflap surgery. Preliminary results suggest superficial lymphatic vessels do not redevelop in muscle flaps.

  3. Vessel size effect on the characteristic frequency of the free surface fluctuations

    International Nuclear Information System (INIS)

    Nam, Ho Yun; Kim, Min Joon; Kim, Jong Man; Choi, Byoung Hae

    2004-01-01

    Studies of the free surface fluctuations is one of the important topics in a liquid metal nuclear reactor using sodium as the coolant that has a free surface in the upper plenum of the reactor vessel. The main reasons for the study on the free surface fluctuations can be summarized as: 1. to secure the structural integrity of a reactor vessel by considering the thermal stress on the vessel wall induced by the fluctuations of the free surface between the hot sodium and cold cover gas, 2. to prevent the cover gas entrainment at the free surface of the sodium because the entrained gas causes a change in the reactivity and also reduces the heat removal capability in the core. Some experimental studies on the free surface fluctuations have been reported. However, most of them focus on the gas entrainment phenomena and only a few works concern the basic characteristics of the free surface fluctuations. Since the thermal stress on the wall is strongly dependent on the amplitude and frequency of the free surface fluctuations, studies on the amplitudes and frequencies should receive more attention. In Nam, empirical formulae on the amplitudes and frequencies with respect to the geometric and hydraulic parameters were introduced. It is an interesting result, but the experiment was performed within the parameter range near the onset point of the fluctuations. In the real reactor condition, larger sized fluctuations may exist and the formula needs to be modified. In this study, we performed experiments on the free surface fluctuations, especially on larger sized fluctuations and made an analysis of the amplitudes and frequencies. The main focus of this paper is the effect of the vessel size on the characteristic frequencies. It is thought to be helpful for finding the scaling laws, for example, designing a scale-down experiment

  4. Fast vessel segmentation in retinal images using multi-scale enhancement and second-order local entropy

    Science.gov (United States)

    Yu, H.; Barriga, S.; Agurto, C.; Zamora, G.; Bauman, W.; Soliz, P.

    2012-03-01

    Retinal vasculature is one of the most important anatomical structures in digital retinal photographs. Accurate segmentation of retinal blood vessels is an essential task in automated analysis of retinopathy. This paper presents a new and effective vessel segmentation algorithm that features computational simplicity and fast implementation. This method uses morphological pre-processing to decrease the disturbance of bright structures and lesions before vessel extraction. Next, a vessel probability map is generated by computing the eigenvalues of the second derivatives of Gaussian filtered image at multiple scales. Then, the second order local entropy thresholding is applied to segment the vessel map. Lastly, a rule-based decision step, which measures the geometric shape difference between vessels and lesions is applied to reduce false positives. The algorithm is evaluated on the low-resolution DRIVE and STARE databases and the publicly available high-resolution image database from Friedrich-Alexander University Erlangen-Nuremberg, Germany). The proposed method achieved comparable performance to state of the art unsupervised vessel segmentation methods with a competitive faster speed on the DRIVE and STARE databases. For the high resolution fundus image database, the proposed algorithm outperforms an existing approach both on performance and speed. The efficiency and robustness make the blood vessel segmentation method described here suitable for broad application in automated analysis of retinal images.

  5. Automated image segmentation and registration of vessel wall MRI for quantitative assessment of carotid artery vessel wall dimensions and plaque composition

    NARCIS (Netherlands)

    Klooster, Ronald van 't

    2014-01-01

    The main goal of this thesis was to develop methods for automated segmentation, registration and classification of the carotid artery vessel wall and plaque components using multi-sequence MR vessel wall images to assess atherosclerosis. First, a general introduction into atherosclerosis and

  6. On the Adequacy of API 521 Relief-Valve Sizing Method for Gas-Filled Pressure Vessels Exposed to Fire

    Directory of Open Access Journals (Sweden)

    Anders Andreasen

    2018-03-01

    Full Text Available In this paper, the adequacy of the legacy API 521 guidance on pressure relief valve (PRV sizing for gas-filled vessels subjected to external fire is investigated. Multiple studies show that in many cases, the installation of a PRV offers little or no protection—therefore provides an unfounded sense of security. Often the vessel wall will be weakened by high temperatures, before the PRV relieving pressure is reached. In this article, a multiparameter study has been performed taking into consideration various vessel sizes, design pressures (implicitly vessel wall thickness, vessel operating pressure, fire type (pool fire or jet fire by applying the methodology presented in the Scandpower guideline. A transient thermomechanical response analysis has been carried out to accurately determine vessel rupture times. It is demonstrated that only vessels with relatively thick walls, as a result of high design pressures, benefit from the presence of a PRV, while for most cases no appreciable increase in the vessel survival time beyond the onset of relief is observed. For most of the cases studied, vessel rupture will occur before the relieving pressure of the PRV is reached.

  7. Finding an optimal method for imaging lymphatic vessels of the upper limb

    International Nuclear Information System (INIS)

    O'Mahony, Susan; Purushotham, Arnie D.; Rose, Sarah L.; Chilvers, Alison J.; Ballinger, James R.; Solanki, Chandra K.; Barber, Robert W.; Peters, A. Michael; Mortimer, Peter S.

    2004-01-01

    Lymphoscintigraphy involves interstitial injection of radiolabelled particulate materials or radioproteins. Although several variations in the technique have been described, their place in clinical practice remains controversial. Traditional diagnostic criteria are based primarily on lymph node appearances but in situations such as breast cancer, where lymph nodes may have been excised, these criteria are of limited use. In these circumstances, lymphatic vessel morphology takes on greater importance as a clinical endpoint, so a method that gives good definition of lymphatic vessels would be useful. In patients with breast cancer, for example, such a method, used before and after lymph node resection, may assist in predicting the development of breast cancer-related lymphoedema. The aim of this study was to optimise a method for the visualisation of lymphatic vessels. Subcutaneous (sc) and intradermal (id) injection sites were compared, and technetium-99m nanocolloid, a particulate material, was compared with 99m Tc-human immunoglobulin (HIG), which is a soluble macromolecule. Twelve normal volunteers were each studied on two occasions. In three subjects, id 99m Tc-HIG was compared with sc 99m Tc-HIG, in three id 99m Tc-nanocolloid was compared with sc 99m Tc-nanocolloid, in three id 99m Tc-HIG was compared with id 99m Tc-nanocolloid and in three sc 99m Tc-HIG was compared with sc 99m Tc-nanocolloid. Endpoints were quality of lymphatic vessel definition, the time after injection at which vessels were most clearly visualised, the rate constant of depot disappearance (k) and the systemic blood accumulation rate as measured by gamma camera imaging over the liver or cardiac blood pool. Excellent definition of lymphatic vessels was obtained following id injection of either radiopharmaceutical, an injection route that was clearly superior to sc. Differences between radiopharmaceuticals were less clear, although after id injection, 99m Tc-HIG gave images that were

  8. Size ratio performance in detecting cerebral aneurysm rupture status is insensitive to small vessel removal.

    Science.gov (United States)

    Lauric, Alexandra; Baharoglu, Merih I; Malek, Adel M

    2013-04-01

    The variable definition of size ratio (SR) for sidewall (SW) vs bifurcation (BIF) aneurysms raises confusion for lesions harboring small branches, such as carotid ophthalmic or posterior communicating locations. These aneurysms are considered SW by many clinicians, but SR methodology classifies them as BIF. To evaluate the effect of ignoring small vessels and SW vs stringent BIF labeling on SR ruptured aneurysm detection performance in borderline aneurysms with small branches, and to reconcile SR-based labeling with clinical SW/BIF classification. Catheter rotational angiographic datasets of 134 consecutive aneurysms (60 ruptured) were automatically measured in 3-dimensional. Stringent BIF labeling was applied to clinically labeled aneurysms, with 21 aneurysms switching label from SW to BIF. Parent vessel size was evaluated both taking into account, and ignoring, small vessels. SR was defined accordingly as the ratio between aneurysm and parent vessel sizes. Univariate and multivariate statistics identified significant features. The square of the correlation coefficient (R(2)) was reported for bivariate analysis of alternative SR calculations. Regardless of SW/BIF labeling method, SR was equally significant in discriminating aneurysm ruptured status (P analysis of alternative SR had a high correlation of R(2) = 0.94 on the whole dataset, and R = 0.98 on the 21 borderline aneurysms. Ignoring small branches from SR calculation maintains rupture status detection performance, while reducing postprocessing complexity and removing labeling ambiguity. Aneurysms adjacent to these vessels can be considered SW for morphometric analysis. It is reasonable to use the clinical SW/BIF labeling when using SR for rupture risk evaluation.

  9. Vessel Segmentation in Retinal Images Using Multi-scale Line Operator and K-Means Clustering.

    Science.gov (United States)

    Saffarzadeh, Vahid Mohammadi; Osareh, Alireza; Shadgar, Bita

    2014-04-01

    Detecting blood vessels is a vital task in retinal image analysis. The task is more challenging with the presence of bright and dark lesions in retinal images. Here, a method is proposed to detect vessels in both normal and abnormal retinal fundus images based on their linear features. First, the negative impact of bright lesions is reduced by using K-means segmentation in a perceptive space. Then, a multi-scale line operator is utilized to detect vessels while ignoring some of the dark lesions, which have intensity structures different from the line-shaped vessels in the retina. The proposed algorithm is tested on two publicly available STARE and DRIVE databases. The performance of the method is measured by calculating the area under the receiver operating characteristic curve and the segmentation accuracy. The proposed method achieves 0.9483 and 0.9387 localization accuracy against STARE and DRIVE respectively.

  10. Evaluation of carotid vessel wall enhancement with image subtraction after gadobenate dimeglumine-enhanced MR angiography

    International Nuclear Information System (INIS)

    Sardanelli, Francesco; Di Leo, Giovanni; Aliprandi, Alberto; Flor, Nicola; Papini, Giacomo D.E.; Roccatagliata, Luca; Cotticelli, Biagio; Nano, Giovanni; Cornalba, Gianpaolo

    2009-01-01

    Objectives: This study was aimed at testing the value of image subtraction for evaluating carotid vessel wall enhancement in contrast-enhanced MR angiography (MRA). Materials and methods: IRB approval was obtained. The scans of 81 consecutive patients who underwent carotid MRA with 0.1 mmol/kg of gadobenate dimeglumine were reviewed. Axial carotid 3D T1-weighted fast low-angle shot sequence before and 3 min after contrast injection were acquired and subtracted (enhanced minus unenhanced). Vessel wall enhancement was assigned a four-point score using native or subtracted images from 0 (no enhancement) to 3 (strong enhancement). Stenosis degree was graded according to NASCET. Results: With native images, vessel wall enhancement was detected in 20/81 patients (25%) and in 20/161 carotids (12%), and scored 2.0 ± 0.6 (mean ± standard deviation); with subtracted images, in 21/81 (26%) and 22/161 (14%), and scored 2.5 ± 0.6, respectively (P < 0.001, Sign test). The overall stenosis degree distribution was: mild, 41/161 (25%); moderate, 77/161 (48%); severe, 43/161 (27%). Carotids with moderate stenosis showed vessel wall enhancement with a frequency (17/77, 22%) significantly higher than that observed in carotids with mild stenosis (1/41, 2%) (P = 0.005, Fisher exact test) and higher, even though with borderline significance (P = 0.078, Fisher exact test), than that observed in carotids with severe stenosis (4/43, 9%). Conclusion: Roughly a quarter of patients undergoing carotid MRA showed vessel wall enhancement. Image subtraction improved vessel wall enhancement conspicuity. Vessel wall enhancement seems to be an event relatively independent from the degree of stenosis. Further studies are warranted to define the relation between vessel wall enhancement and histopathology, inflammatory status, and instability.

  11. Supervised retinal vessel segmentation from color fundus images based on matched filtering and AdaBoost classifier.

    Directory of Open Access Journals (Sweden)

    Nogol Memari

    Full Text Available The structure and appearance of the blood vessel network in retinal fundus images is an essential part of diagnosing various problems associated with the eyes, such as diabetes and hypertension. In this paper, an automatic retinal vessel segmentation method utilizing matched filter techniques coupled with an AdaBoost classifier is proposed. The fundus image is enhanced using morphological operations, the contrast is increased using contrast limited adaptive histogram equalization (CLAHE method and the inhomogeneity is corrected using Retinex approach. Then, the blood vessels are enhanced using a combination of B-COSFIRE and Frangi matched filters. From this preprocessed image, different statistical features are computed on a pixel-wise basis and used in an AdaBoost classifier to extract the blood vessel network inside the image. Finally, the segmented images are postprocessed to remove the misclassified pixels and regions. The proposed method was validated using publicly accessible Digital Retinal Images for Vessel Extraction (DRIVE, Structured Analysis of the Retina (STARE and Child Heart and Health Study in England (CHASE_DB1 datasets commonly used for determining the accuracy of retinal vessel segmentation methods. The accuracy of the proposed segmentation method was comparable to other state of the art methods while being very close to the manual segmentation provided by the second human observer with an average accuracy of 0.972, 0.951 and 0.948 in DRIVE, STARE and CHASE_DB1 datasets, respectively.

  12. Fracture fragility of HFIR vessel caused by random crack size or random toughness

    International Nuclear Information System (INIS)

    Chang, Shih-Jung; Proctor, L.D.

    1993-01-01

    This report discuses the probability of fracture (fracture fragility) versus a range of applied hoop stresses along the HFIR vessel which is obtained as an estimate of its fracture capacity. Both the crack size and the fracture toughness are assumed to be random variables that follow given distribution functions. Possible hoop stress is based on the numerical solution of the vessel response by applying a point pressure-pulse it the center of the fluid volume within the vessel. Both the fluid-structure interaction and radiation embrittlement are taken into consideration. Elastic fracture mechanics is used throughout the analysis. The probability of vessel fracture for a single crack caused by either a variable crack depth or a variable toughness is first derived. Then the probability of fracture with multiple number of cracks is obtained. The probability of fracture is further extended to include different levels of confidence and variability. It, therefore, enables one to estimate the high confidence and low probability capacity accident load

  13. Classification of Vessels in Single-Pol COSMO-SkyMed Images Based on Statistical and Structural Features

    Directory of Open Access Journals (Sweden)

    Fan Wu

    2015-05-01

    Full Text Available Vessel monitoring is one of the most important maritime applications of Synthetic Aperture Radar (SAR data. Because of the dihedral reflections between the vessel hull and sea surface and the trihedral reflections among superstructures, vessels usually have strong backscattering in SAR images. Furthermore, in high-resolution SAR images, detailed information on vessel structures can be observed, allowing for vessel classification in high-resolution SAR images. This paper focuses on the feature analysis of merchant vessels, including bulk carriers, container ships and oil tankers, in 3 m resolution COSMO-SkyMed stripmap HIMAGE mode images and proposes a method for vessel classification. After preprocessing, a feature vector is estimated by calculating the average value of the kernel density estimation, three structural features and the mean backscattering coefficient. Support vector machine (SVM classifier is used for the vessel classification, and the results are compared with traditional methods, such as the K-nearest neighbor algorithm (K-NN and minimum distance classifier (MDC. In situ investigations are conducted during the SAR data acquisition. Corresponding Automatic Identification System (AIS reports are also obtained as ground truth to evaluate the effectiveness of the classifier. The preliminary results show that the combination of the average value of the kernel density estimation and mean backscattering coefficient has good ability for classifying the three types of vessels. When adding the three structural features, the results slightly improve. The result of the SVM classifier is better than that of K-NN and MDC. However, the SVM requires more time, when the parameters of the kernel are estimated.

  14. Probabilistic retinal vessel segmentation

    Science.gov (United States)

    Wu, Chang-Hua; Agam, Gady

    2007-03-01

    Optic fundus assessment is widely used for diagnosing vascular and non-vascular pathology. Inspection of the retinal vasculature may reveal hypertension, diabetes, arteriosclerosis, cardiovascular disease and stroke. Due to various imaging conditions retinal images may be degraded. Consequently, the enhancement of such images and vessels in them is an important task with direct clinical applications. We propose a novel technique for vessel enhancement in retinal images that is capable of enhancing vessel junctions in addition to linear vessel segments. This is an extension of vessel filters we have previously developed for vessel enhancement in thoracic CT scans. The proposed approach is based on probabilistic models which can discern vessels and junctions. Evaluation shows the proposed filter is better than several known techniques and is comparable to the state of the art when evaluated on a standard dataset. A ridge-based vessel tracking process is applied on the enhanced image to demonstrate the effectiveness of the enhancement filter.

  15. Extrinsic ureteropelvic junction obstruction from a crossing renal vessel: demography and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Rooks, V.J.; Lebowitz, R.L. [Children' s Hospital and Harvard Medical School, Dept. of Radiology, Boston, MA (United States)

    2001-02-01

    Background. The increase in the use of prenatal ultrasound has revolutionized the detection of hydronephrosis and has had an unanticipated consequence. Objective. To describe the new demographics of symptomatic ureteropelvic junction (UPJ) obstruction and the characteristic imaging findings, when the obstruction is extrinsic, from a crossing renal vessel. Materials and methods. From a uroradiology database (1994 through 1999) we identified children with surgically corrected UPJ obstruction from intrinsic and extrinsic causes. Results. One hundred children had symptomatic UPJ obstruction treated by surgery. In 51 (49 %), obstruction was due to a crossing vessel. One hundred and one had UPJ obstruction detected by prenatal sonography. Only 11 (11 %) were due to a vessel. Two clinical and imaging findings were strongly suggestive of obstruction from a vessel: (1) in 5 of the 100 children the symptoms (pain, nausea, and vomiting) were intermittent. Only when symptoms were present were there hydronephrosis and obstruction; (2) in 51 of the 100 children a short segment of ureter, just below the UPJ, was filled with contrast or urine (on renal sonography, intravenous urography, or retrograde/antegrade ureterography). Conclusions. Extrinsic UPJ obstruction caused by a vessel is an uncommon cause of obstruction when all patients are considered. However, in symptomatic older patients whose hydronephrosis was not first identified on prenatal sonography, a vessel was the cause of obstruction in one-half. (orig.)

  16. Imaging findings in the right aortic arch with mirror image branching of arch vessels: An unusual cause of dysphagia

    Directory of Open Access Journals (Sweden)

    Guneet Singh

    2015-01-01

    Full Text Available We report a case of a 72-year-old female with a right aortic arch with mirror-image branching of arch vessels presenting with dysphagia, and characteristic images on barium esophagogram, contrast-enhanced computed tomography scan, and magnetic resonance aortography. Right-sided thoracic aortic arch with mirror-image branching of the brachiocephalic vessels causing dysphagia without associated congenital cardiac anomalies is extremely uncommon. Right-sided aortic arch is a rare congenital abnormality with incidence of 0.05-0.1% in the normal population. Anomalies of great vessels are usually incidental findings, because they are asymptomatic. Right aortic arch infrequently presents with a vascular ring that can cause complete or partial obstruction of the trachea and/or esophagus. The understanding of this arch anomaly is based on Edward′s hypothesis about the double arch system during embryonic developmental.

  17. Three-dimensional imaging of the aortic vessel wall using an elastin-specific magnetic resonance contrast agent.

    Science.gov (United States)

    Makowski, Marcus R; Preissel, Anne; von Bary, Christian; Warley, Alice; Schachoff, Sylvia; Keithan, Alexandra; Cesati, Richard R; Onthank, David C; Schwaiger, Markus; Robinson, Simon P; Botnar, René M

    2012-07-01

    The aim of this study was to demonstrate the feasibility of high-resolution 3-dimensional aortic vessel wall imaging using a novel elastin-specific magnetic resonance contrast agent (ESMA) in a large animal model. The thoracic aortic vessel wall of 6 Landrace pigs was imaged using a novel ESMA and a nonspecific control agent. On day 1, imaging was performed before and after the administration of a nonspecific control agent, gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA; Bayer Schering AG, Berlin, Germany). On day 3, identical scans were repeated before and after the administration of a novel ESMA (Lantheus Medical Imaging, North Billerica, Massachusetts). Three-dimensional inversion recovery gradient echo delayed-enhancement imaging and magnetic resonance (MR) angiography of the thoracic aortic vessel wall were performed on a 1.5-T MR scanner (Achieva; Philips Medical Systems, the Netherlands). The signal-to-noise ratio and the contrast-to-noise ratio of arterial wall enhancement, including the time course of enhancement, were assessed for ESMA and Gd-DTPA. After the completion of imaging sessions, histology, electron microscopy, and inductively coupled plasma mass spectroscopy were performed to localize and quantify the gadolinium bound to the arterial vessel wall. Administration of ESMA resulted in a strong enhancement of the aortic vessel wall on delayed-enhancement imaging, whereas no significant enhancement could be measured with Gd-DTPA. Ninety to 100 minutes after the administration of ESMA, significantly higher signal-to-noise ratio and contrast-to-noise ratio could be measured compared with the administration of Gd-DTPA (45.7 ± 9.6 vs 13.2 ± 3.5, P wall imaging using a novel ESMA in a large animal model under conditions resembling a clinical setting. Such an approach could be useful for the fast 3-dimensional assessment of the arterial vessel wall in the context of atherosclerosis, aortic aneurysms, and hypertension.

  18. Role of 3.0 T MR vessel wall imaging for identifying the activity of takayasu arteritis

    International Nuclear Information System (INIS)

    Liu Xiaosheng; Xu Jianrong; Zhao Huilin; Cheng Fang; Lu Qing; Yao Qiuying

    2010-01-01

    Objective: To analyze and explore the value of 3 T high resolution magnetic resonance vessel wall imaging for identifying the activity of Takayasu arteritis. Methods: Twenty-six consecutive patients with Takayasu arteritis underwent 3.0 T high resolution MR vessel wall imaging on supraortic vessels (according to the classification of Lupi-Herrea, type I and III were included). Sixteen patients were in active phase and 10 in inactive phase based on the Kerr criteria. The MR vessel wall imaging appearances of Takayasu arteritis were compared between the active phase and inactive phase cases. Results: Wall thickening was demonstrated in all involved arteries. There were statistically significant differences between active phase and inactive phase cases in MR appearances including multi-ring thickening of vessel wall (75/80 and 18/50), arterial inner wail enhancement (50/80 and 19/50), obscurity of perivascular fat (55/80 and 18/50, X 2 =50.39, 7.41, 13.40, P<0.01). There was also a statistically significant difference in the thickness of carotid artery wall between the two groups [ (3.8 ± 0.2) mm vs (2.5 ± 0.8) mm]. Conclusion: 3 T high resolution MR vessel wall imaging is valuable for identifying the activity of Takayasu arteritis. (authors)

  19. A wide angle view imaging diagnostic with all reflective, in-vessel optics at JET

    Energy Technology Data Exchange (ETDEWEB)

    Clever, M. [Institute of Energy and Climate Research – Plasma Physics, Forschungszentrum Jülich GmbH, Association EURATOM-FZJ, 52425 Jülich (Germany); Arnoux, G.; Balshaw, N. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Garcia-Sanchez, P. [Laboratorio Nacional de Fusion, Asociacion EURATOM-CIEMAT, Madrid (Spain); Patel, K. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Sergienko, G. [Institute of Energy and Climate Research – Plasma Physics, Forschungszentrum Jülich GmbH, Association EURATOM-FZJ, 52425 Jülich (Germany); Soler, D. [Winlight System, 135 rue Benjamin Franklin, ZA Saint Martin, F-84120 Pertuis (France); Stamp, M.F.; Williams, J.; Zastrow, K.-D. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2013-10-15

    Highlights: ► A new wide angle view camera system has been installed at JET. ► The system helps to protect the ITER-like wall plasma facing components from damage. ► The coverage of the vessel by camera observation systems was increased. ► The system comprises an in-vessel part with parabolic and flat mirrors. ► The required image quality for plasma monitoring and wall protection was delivered. -- Abstract: A new wide angle view camera system has been installed at JET in preparation for the ITER-like wall campaigns. It considerably increases the coverage of the vessel by camera observation systems and thereby helps to protect the – compared to carbon – more fragile plasma facing components from damage. The system comprises an in-vessel part with parabolic and flat mirrors and an ex-vessel part with beam splitters, lenses and cameras. The system delivered the image quality required for plasma monitoring and wall protection.

  20. Hybrid Segmentation of Vessels and Automated Flow Measures in In-Vivo Ultrasound Imaging

    DEFF Research Database (Denmark)

    Moshavegh, Ramin; Martins, Bo; Hansen, Kristoffer Lindskov

    2016-01-01

    Vector Flow Imaging (VFI) has received an increasing attention in the scientific field of ultrasound, as it enables angle independent visualization of blood flow. VFI can be used in volume flow estimation, but a vessel segmentation is needed to make it fully automatic. A novel vessel segmentation...

  1. Image processing algorithm for robot tracking in reactor vessel

    International Nuclear Information System (INIS)

    Kim, Tae Won; Choi, Young Soo; Lee, Sung Uk; Jeong, Kyung Min; Kim, Nam Kyun

    2011-01-01

    In this paper, we proposed an image processing algorithm to find the position of an underwater robot in the reactor vessel. Proposed algorithm is composed of Modified SURF(Speeded Up Robust Feature) based on Mean-Shift and CAMSHIFT(Continuously Adaptive Mean Shift Algorithm) based on color tracking algorithm. Noise filtering using luminosity blend method and color clipping are preprocessed. Initial tracking area for the CAMSHIFT is determined by using modified SURF. And then extracting the contour and corner points in the area of target tracked by CAMSHIFT method. Experiments are performed at the reactor vessel mockup and verified to use in the control of robot by visual tracking

  2. Feasibility evaluation of 3D photoacoustic imaging of blood vessel structure using multiple wavelengths with a handheld probe

    Science.gov (United States)

    Uchimoto, Yo; Namita, Takeshi; Kondo, Kengo; Yamakawa, Makoto; Shiina, Tsuyoshi

    2018-02-01

    Photoacoustic imaging is anticipated for use in portraying blood vessel structures (e.g. neovascularization in inflamed regions). To reduce invasiveness and enhance ease handling, we developed a handheld photoacoustic imaging system using multiple wavelengths. The usefulness of the proposed system was investigated in phantom experiments and in vivo measurements. A silicon tube was embedded into chicken breast meat to simulate the blood vessel. The tube was filled with ovine blood. Then laser light was guided to the phantom surface by an optical fiber bundle close to the linear ultrasound probe. Photoacoustic images were obtained at 750-950 nm wavelengths. Strong photoacoustic signals from the boundary between blood and silicon tube are observed in these images. The shape of photoacoustic spectrum at the boundary resembles that of the HbO2 absorption spectrum at 750-920 nm. In photoacoustic images, similarity between photoacoustic spectrum and HbO2 absorption spectrum was evaluated by calculating the normalized correlation coefficient. Results show high correlation in regions of strong photoacoustic signals in photoacoustic images. These analyses demonstrate the feasibility of portraying blood vessel structures under practical conditions. To evaluate the feasibility of three-dimensional vascular imaging, in vivo experiments were conducted using three wavelengths. A right hand and ultrasound probe were set in degassed water. By scanning a probe, cross-sectional ultrasound and photoacoustic images were obtained at each location. Then, all ultrasound or photoacoustic images were piled up respectively. Then three-dimensional images were constructed. Resultant images portrayed blood vessel-like structures three-dimensionally. Furthermore, to distinguish blood vessels from other tissues (e.g. skin), distinguishing images of them were constructed by comparing photoacoustic signal intensity among three wavelengths. The resultant image portrayed blood vessels as

  3. Mock-up test of remote controlled dismantling apparatus for large-sized vessels (contract research)

    Energy Technology Data Exchange (ETDEWEB)

    Myodo, Masato; Miyajima, Kazutoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Okane, Shogo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

    2001-03-01

    The Remote dismantling apparatus, which is equipped with multi-units for functioning of washing, cutting, collection of cut pieces and so on, has been constructed to dismantle the large-sized vessels in the JAERI's Reprocessing Test Facility (JRTF). The apparatus has five-axis movement capability and its operation is performed remotely. The mock-up tests were performed to evaluate the applicability of the apparatus to actual dismantling activities by using the mock-ups of LV-3 and LV-5 in the facility. It was confirmed that each unit was satisfactory functioned by remote operation. Efficient procedures for dismantling the large-sized vessel was studied and various date was obtained in the mock-up tests. This apparatus was found to be applicable for the actual dismantling activity in JRTF. (author)

  4. Mock-up test of remote controlled dismantling apparatus for large-sized vessels (contract research)

    International Nuclear Information System (INIS)

    Myodo, Masato; Miyajima, Kazutoshi; Okane, Shogo

    2001-03-01

    The Remote dismantling apparatus, which is equipped with multi-units for functioning of washing, cutting, collection of cut pieces and so on, has been constructed to dismantle the large-sized vessels in the JAERI's Reprocessing Test Facility (JRTF). The apparatus has five-axis movement capability and its operation is performed remotely. The mock-up tests were performed to evaluate the applicability of the apparatus to actual dismantling activities by using the mock-ups of LV-3 and LV-5 in the facility. It was confirmed that each unit was satisfactory functioned by remote operation. Efficient procedures for dismantling the large-sized vessel was studied and various date was obtained in the mock-up tests. This apparatus was found to be applicable for the actual dismantling activity in JRTF. (author)

  5. Fully automatic algorithm for the analysis of vessels in the angiographic image of the eye fundus

    Directory of Open Access Journals (Sweden)

    Koprowski Robert

    2012-06-01

    Full Text Available Abstract Background The available scientific literature contains descriptions of manual, semi-automated and automated methods for analysing angiographic images. The presented algorithms segment vessels calculating their tortuosity or number in a given area. We describe a statistical analysis of the inclination of the vessels in the fundus as related to their distance from the center of the optic disc. Methods The paper presents an automated method for analysing vessels which are found in angiographic images of the eye using a Matlab implemented algorithm. It performs filtration and convolution operations with suggested masks. The result is an image containing information on the location of vessels and their inclination angle in relation to the center of the optic disc. This is a new approach to the analysis of vessels whose usefulness has been confirmed in the diagnosis of hypertension. Results The proposed algorithm analyzed and processed the images of the eye fundus using a classifier in the form of decision trees. It enabled the proper classification of healthy patients and those with hypertension. The result is a very good separation of healthy subjects from the hypertensive ones: sensitivity - 83%, specificity - 100%, accuracy - 96%. This confirms a practical usefulness of the proposed method. Conclusions This paper presents an algorithm for the automatic analysis of morphological parameters of the fundus vessels. Such an analysis is performed during fluorescein angiography of the eye. The presented algorithm automatically calculates the global statistical features connected with both tortuosity of vessels and their total area or their number.

  6. Measurement of flow velocity fields in small vessel-mimic phantoms and vessels of small animals using micro ultrasonic particle image velocimetry (micro-EPIV).

    Science.gov (United States)

    Qian, Ming; Niu, Lili; Wang, Yanping; Jiang, Bo; Jin, Qiaofeng; Jiang, Chunxiang; Zheng, Hairong

    2010-10-21

    Determining a multidimensional velocity field within microscale opaque fluid flows is needed in areas such as microfluidic devices, biofluid mechanics and hemodynamics research in animal studies. The ultrasonic particle image velocimetry (EchoPIV) technique is appropriate for measuring opaque flows by taking advantage of PIV and B-mode ultrasound contrast imaging. However, the use of clinical ultrasound systems for imaging flows in small structures or animals has limitations associated with spatial resolution. This paper reports on the development of a high-resolution EchoPIV technique (termed as micro-EPIV) and its application in measuring flows in small vessel-mimic phantoms and vessels of small animals. Phantom experiments demonstrate the validity of the technique, providing velocity estimates within 4.1% of the analytically derived values with regard to the flows in a small straight vessel-mimic phantom, and velocity estimates within 5.9% of the computationally simulated values with regard to the flows in a small stenotic vessel-mimic phantom. Animal studies concerning arterial and venous flows of living rats and rabbits show that the micro-EPIV-measured peak velocities within several cardiac cycles are about 25% below the values measured by the ultrasonic spectral Doppler technique. The micro-EPIV technique is able to effectively measure the flow fields within microscale opaque fluid flows.

  7. Measurement of flow velocity fields in small vessel-mimic phantoms and vessels of small animals using micro ultrasonic particle image velocimetry (micro-EPIV)

    International Nuclear Information System (INIS)

    Qian Ming; Niu Lili; Jiang Bo; Jin Qiaofeng; Jiang Chunxiang; Zheng Hairong; Wang Yanping

    2010-01-01

    Determining a multidimensional velocity field within microscale opaque fluid flows is needed in areas such as microfluidic devices, biofluid mechanics and hemodynamics research in animal studies. The ultrasonic particle image velocimetry (EchoPIV) technique is appropriate for measuring opaque flows by taking advantage of PIV and B-mode ultrasound contrast imaging. However, the use of clinical ultrasound systems for imaging flows in small structures or animals has limitations associated with spatial resolution. This paper reports on the development of a high-resolution EchoPIV technique (termed as micro-EPIV) and its application in measuring flows in small vessel-mimic phantoms and vessels of small animals. Phantom experiments demonstrate the validity of the technique, providing velocity estimates within 4.1% of the analytically derived values with regard to the flows in a small straight vessel-mimic phantom, and velocity estimates within 5.9% of the computationally simulated values with regard to the flows in a small stenotic vessel-mimic phantom. Animal studies concerning arterial and venous flows of living rats and rabbits show that the micro-EPIV-measured peak velocities within several cardiac cycles are about 25% below the values measured by the ultrasonic spectral Doppler technique. The micro-EPIV technique is able to effectively measure the flow fields within microscale opaque fluid flows.

  8. Machine Learning for Quantification of Small Vessel Disease Imaging Biomarkers

    NARCIS (Netherlands)

    Ghafoorian, M.

    2018-01-01

    This thesis is devoted to developing fully automated methods for quantification of small vessel disease imaging bio-markers, namely WMHs and lacunes, using vari- ous machine learning/deep learning and computer vision techniques. The rest of the thesis is organized as follows: Chapter 2 describes

  9. Combination probe for optically assisted ultrasonic velocity-change imaging aimed at detecting unstable blood vessel plaque

    Science.gov (United States)

    Tanigawa, Shohei; Mano, Kazune; Wada, Kenji; Matsunaka, Toshiyuki; Horinaka, Hiromichi

    2016-04-01

    Blood vessel plaque with a large lipid core is at risk of becoming thrombus and is likely to induce acute heart disease. To prevent this, it is necessary to determine not only the plaque's size but also its chemical composition. We, therefore, made the prototype of a combination probe to diagnose carotid artery plaque. It is used to differentiate propagation characteristics between light spectra and ultrasonic images. By propagating light and ultrasound along a common direction, it is possible to effectively warm the diagnosis domain. Moreover, the probe is thought to be compact and be easy to use for diagnosing human carotid artery plaque. We applied the combination probe to a carotid artery phantom with a lipid area and obtained an image of the ultrasonic velocity change in the fatty area.

  10. Vessel bifurcation localization based on intraoperative three-dimensional ultrasound and catheter path for image-guided catheter intervention of oral cancers.

    Science.gov (United States)

    Luan, Kuan; Ohya, Takashi; Liao, Hongen; Kobayashi, Etsuko; Sakuma, Ichiro

    2013-03-01

    We present a method to localize intraoperative target vessel bifurcations under bones for ultrasound (US) image-guided catheter interventions. A catheter path is recorded to acquire skeletons for the target vessel bifurcations that cannot be imaged by intraoperative US. The catheter path is combined with the centerlines of the three-dimensional (3D) US image to construct a preliminary skeleton. Based on the preliminary skeleton, the orientations of target vessels are determined by registration with the preoperative image and the bifurcations were localized by computing the vessel length. An accurate intraoperative vessel skeleton is obtained for correcting the preoperative image to compensate for vessel deformation. A reality check of the proposed method was performed in a phantom experiment. Reasonable results were obtained. The in vivo experiment verified the clinical workflow of the proposed method in an in vivo environment. The accuracy of the centerline length of the vessel for localizing the target artery bifurcation was 2.4mm. These results suggest that the proposed method can allow the catheter tip to stop at the target artery bifurcations and enter into the target arteries. This method can be applied for virtual reality-enhanced image-guided catheter intervention of oral cancers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Automated method for identification and artery-venous classification of vessel trees in retinal vessel networks.

    Science.gov (United States)

    Joshi, Vinayak S; Reinhardt, Joseph M; Garvin, Mona K; Abramoff, Michael D

    2014-01-01

    The separation of the retinal vessel network into distinct arterial and venous vessel trees is of high interest. We propose an automated method for identification and separation of retinal vessel trees in a retinal color image by converting a vessel segmentation image into a vessel segment map and identifying the individual vessel trees by graph search. Orientation, width, and intensity of each vessel segment are utilized to find the optimal graph of vessel segments. The separated vessel trees are labeled as primary vessel or branches. We utilize the separated vessel trees for arterial-venous (AV) classification, based on the color properties of the vessels in each tree graph. We applied our approach to a dataset of 50 fundus images from 50 subjects. The proposed method resulted in an accuracy of 91.44% correctly classified vessel pixels as either artery or vein. The accuracy of correctly classified major vessel segments was 96.42%.

  12. Gadolinium Enhanced MR Coronary Vessel Wall Imaging at 3.0 Tesla

    Directory of Open Access Journals (Sweden)

    Sebastian Kelle

    2010-01-01

    Full Text Available Purpose. We evaluated the influence of the time between low-dose gadolinium (Gd contrast administration and coronary vessel wall enhancement (LGE detected by 3T magnetic resonance imaging (MRI in healthy subjects and patients with coronary artery disease (CAD. Materials and Methods. Four healthy subjects (4 men, mean age 29  ±  3 years and eleven CAD patients (6 women, mean age 61±10 years were studied on a commercial 3.0 Tesla (T whole-body MR imaging system (Achieva 3.0 T; Philips, Best, The Netherlands. T1-weighted inversion-recovery coronary magnetic resonance imaging (MRI was repeated up to 75 minutes after administration of low-dose Gadolinium (Gd (0.1 mmol/kg Gd-DTPA. Results. LGE was seen in none of the healthy subjects, however in all of the CAD patients. In CAD patients, fifty-six of 62 (90.3% segments showed LGE of the coronary artery vessel wall at time-interval 1 after contrast. At time-interval 2, 34 of 42 (81.0% and at time-interval 3, 29 of 39 evaluable segments (74.4% were enhanced. Conclusion. In this work, we demonstrate LGE of the coronary artery vessel wall using 3.0 T MRI after a single, low-dose Gd contrast injection in CAD patients but not in healthy subjects. In the majority of the evaluated coronary segments in CAD patients, LGE of the coronary vessel wall was already detectable 30–45 minutes after administration of the contrast agent.

  13. The impact of vessel size on vulnerability curves: data and models for within-species variability in saplings of aspen, Populus tremuloides Michx.

    Science.gov (United States)

    Cai, Jing; Tyree, Melvin T

    2010-07-01

    The objective of this study was to quantify the relationship between vulnerability to cavitation and vessel diameter within a species. We measured vulnerability curves (VCs: percentage loss hydraulic conductivity versus tension) in aspen stems and measured vessel-size distributions. Measurements were done on seed-grown, 4-month-old aspen (Populus tremuloides Michx) grown in a greenhouse. VCs of stem segments were measured using a centrifuge technique and by a staining technique that allowed a VC to be constructed based on vessel diameter size-classes (D). Vessel-based VCs were also fitted to Weibull cumulative distribution functions (CDF), which provided best-fit values of Weibull CDF constants (c and b) and P(50) = the tension causing 50% loss of hydraulic conductivity. We show that P(50) = 6.166D(-0.3134) (R(2) = 0.995) and that b and 1/c are both linear functions of D with R(2) > 0.95. The results are discussed in terms of models of VCs based on vessel D size-classes and in terms of concepts such as the 'pit area hypothesis' and vessel pathway redundancy.

  14. Magnetic resonance imaging of water ascent in embolized xylem vessels of grapevine stem segments

    Science.gov (United States)

    Mingtao Wang; Melvin T. Tyree; Roderick E. Wasylishen

    2013-01-01

    Temporal and spatial information about water refilling of embolized xylem vessels and the rate of water ascent in these vessels is critical for understanding embolism repair in intact living vascular plants. High-resolution 1H magnetic resonance imaging (MRI) experiments have been performed on embolized grapevine stem segments while they were...

  15. Magnetic resonance imaging of the heart and great vessels

    International Nuclear Information System (INIS)

    Naitoh, Hiroaki; Nishimura, Tsunehiko; Takamiya, Makoto; Kozuka, Takahiro.

    1985-01-01

    About sixty subjects with normal heart or various cardiovascular diseases were examined with 0.35 or 1.5 T superconductive magnetic resonance imaging (MRI) system, and ECG-gated spin-echo multislice technique was used to evaluate cardiovascular anatomy. MRI accurately demonstrated ventricular wall thinning caused by myocardial infarction and asymmetric ventricular hypertrophy owing to cardiomyopathy. Rheumatic valvular thickening, congenital cardiac malformations, aortic aneurysm and dissection were also clearly demonstrated by gated MRI without the use of any contrast media. MRI was shown to be an excellent non-invasive imaging modality for evaluation of pathoanatomy of the heart and great vessels. (author)

  16. Autonomous radiation monitoring of small vessels

    International Nuclear Information System (INIS)

    Ziock, K.P.; Cheriyadat, A.; Fabris, L.; Goddard, J.; Hornback, D.; Karnowski, T.; Kerekes, R.; Newby, J.

    2011-01-01

    Small private vessels are one avenue by which nuclear materials may be smuggled across international borders. While one can contemplate using the land-based approach of radiation portal monitors on the navigable waterways that lead to many ports, these systems are ill-suited to the problem. In contrast to roadways, where lanes segregate vehicles, and motion is well controlled by inspection booths; channels, inlets, and rivers present chaotic traffic patterns populated by vessels of all sizes. A unique solution to this problem is based on a portal-less portal monitor designed to handle free-flowing traffic on roadways with up to five-traffic lanes. The instrument uses a combination of visible-light and gamma-ray imaging to acquire and link radiation images to individual vehicles. This paper presents the results of a recent test of the system in a maritime setting.

  17. A multi-scale tensor voting approach for small retinal vessel segmentation in high resolution fundus images.

    Science.gov (United States)

    Christodoulidis, Argyrios; Hurtut, Thomas; Tahar, Houssem Ben; Cheriet, Farida

    2016-09-01

    Segmenting the retinal vessels from fundus images is a prerequisite for many CAD systems for the automatic detection of diabetic retinopathy lesions. So far, research efforts have concentrated mainly on the accurate localization of the large to medium diameter vessels. However, failure to detect the smallest vessels at the segmentation step can lead to false positive lesion detection counts in a subsequent lesion analysis stage. In this study, a new hybrid method for the segmentation of the smallest vessels is proposed. Line detection and perceptual organization techniques are combined in a multi-scale scheme. Small vessels are reconstructed from the perceptual-based approach via tracking and pixel painting. The segmentation was validated in a high resolution fundus image database including healthy and diabetic subjects using pixel-based as well as perceptual-based measures. The proposed method achieves 85.06% sensitivity rate, while the original multi-scale line detection method achieves 81.06% sensitivity rate for the corresponding images (p<0.05). The improvement in the sensitivity rate for the database is 6.47% when only the smallest vessels are considered (p<0.05). For the perceptual-based measure, the proposed method improves the detection of the vasculature by 7.8% against the original multi-scale line detection method (p<0.05). Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Application of electron beam welding to large size pressure vessels made of thick low alloy steel

    International Nuclear Information System (INIS)

    Kuri, S.; Yamamoto, M.; Aoki, S.; Kimura, M.; Nayama, M.; Takano, G.

    1993-01-01

    The authors describe the results of studies for application of the electron beam welding to the large size pressure vessels made of thick low alloy steel (ASME A533 Gr.B cl.2 and A533 Gr.A cl.1). Two major problems for applying the EBW, the poor toughness of weld metal and the equipment to weld huge pressure vessels are focused on. For the first problem, the effects of Ni content of weld metal, welding conditions and post weld heat treatment are investigated. For the second problem, an applicability of the local vacuum EBW to a large size pressure vessel made of thick plate is qualified by the construction of a 120 mm thick, 2350 mm outside diameter cylindrical model. The model was electron beam welded using local vacuum chamber and the performance of the weld joint is investigated. Based on these results, the electron beam welding has been applied to the production of a steam generator for a PWR. (author). 3 refs., 10 figs., 4 tabs

  19. Autonomous Radiation Monitoring of Small Vessels

    International Nuclear Information System (INIS)

    Fabris, Lorenzo; Hornback, Donald Eric

    2010-01-01

    Small private vessels are one avenue by which nuclear materials may be smuggled across international borders. While one can contemplate using the terrestrial approach of radiation portal monitors on the navigable waterways that lead to many ports, these systems are ill-suited to the problem. They require vehicles to pass at slow speeds between two closely-spaced radiation sensors, relying on the uniformity of vehicle sizes to space the detectors, and on proximity to link an individual vehicle to its radiation signature. In contrast to roadways where lanes segregate vehicles, and motion is well controlled by inspection booths; channels, inlets, and rivers present chaotic traffic patterns populated by vessels of all sizes. We have developed a unique solution to this problem based on our portal-less portal monitor instrument that is designed to handle free-flowing traffic on roadways with up to five-traffic lanes. The instrument uses a combination of visible-light and gamma-ray imaging to acquire and link radiation images to individual vehicles. It was recently tested in a maritime setting. In this paper we present the instrument, how it functions, and the results of the recent tests.

  20. Calibration-free device sizing using an inverse geometry x-ray system

    International Nuclear Information System (INIS)

    Tomkowiak, Michael T.; Speidel, Michael A.; Raval, Amish N.; Van Lysel, Michael S.

    2011-01-01

    Purpose: Quantitative coronary angiography (QCA) can be used to support device size selection for cardiovascular interventions. The accuracy of QCA measurements using conventional x-ray fluoroscopy depends on proper calibration using a reference object and avoiding vessel foreshortening. The authors have developed a novel interventional device sizing method using the inverse geometry scanning-beam digital x-ray (SBDX) fluoroscopy system. The proposed method can measure the diameter and length of vessel segments without imaging a reference object and when vessels appear foreshortened. Methods: SBDX creates multiple tomosynthetic x-ray images corresponding to planes through the patient volume. The structures that lie in the plane are in focus and the features above and below the plane are blurred. Three-dimensional localization of the vessel edges was performed by examining the degree of blurring at each image plane. A 3D vessel centerline was created and used to determine vessel magnification and angulation relative to the image planes. Diameter measurements were performed using a model-based method and length measurements were calculated from the 3D centerline. Phantom validation was performed by measuring the diameter and length of vessel segments with nominal diameters ranging from 0.5 to 2.8 mm and nominal lengths of 42 mm. The phantoms were imaged at a range of positions between the source and the detector (±16 cm relative to isocenter) and with a range of foreshortening angles (0 deg. - 75 deg.). Results: Changes in vessel phantom position created magnifications ranging from 87% to 118% relative to isocenter magnification. Average diameter errors were less than 0.15 mm. Average length measurements were within 1% (0.3 mm) of the true length. No trends were observed between measurement accuracy and magnification. Changes in vessel phantom orientation resulted in decreased apparent length down to 28% of the original nonforeshortened length. Average diameter

  1. Children's accuracy of portion size estimation using digital food images: effects of interface design and size of image on computer screen.

    Science.gov (United States)

    Baranowski, Tom; Baranowski, Janice C; Watson, Kathleen B; Martin, Shelby; Beltran, Alicia; Islam, Noemi; Dadabhoy, Hafza; Adame, Su-heyla; Cullen, Karen; Thompson, Debbe; Buday, Richard; Subar, Amy

    2011-03-01

    To test the effect of image size and presence of size cues on the accuracy of portion size estimation by children. Children were randomly assigned to seeing images with or without food size cues (utensils and checked tablecloth) and were presented with sixteen food models (foods commonly eaten by children) in varying portion sizes, one at a time. They estimated each food model's portion size by selecting a digital food image. The same food images were presented in two ways: (i) as small, graduated portion size images all on one screen or (ii) by scrolling across large, graduated portion size images, one per sequential screen. Laboratory-based with computer and food models. Volunteer multi-ethnic sample of 120 children, equally distributed by gender and ages (8 to 13 years) in 2008-2009. Average percentage of correctly classified foods was 60·3 %. There were no differences in accuracy by any design factor or demographic characteristic. Multiple small pictures on the screen at once took half the time to estimate portion size compared with scrolling through large pictures. Larger pictures had more overestimation of size. Multiple images of successively larger portion sizes of a food on one computer screen facilitated quicker portion size responses with no decrease in accuracy. This is the method of choice for portion size estimation on a computer.

  2. Comparison of vessel contrast measured with a scanning-beam digital x-ray system and an image intensifier/television system

    International Nuclear Information System (INIS)

    Speidel, Michael A.; Wilfley, Brian P.; Heanue, Joseph A.; Betts, Timothy D.; Van Lysel, Michael S.

    2001-01-01

    Vessel contrast was measured in the fluoroscopic images produced by a scanning-beam digital x-ray (SBDX) system and an image intensifier/television (II/TV) based system. The SBDX system electronically scans a series of pencil x-ray beams across the patient, each of which is directed at a distant small-area detector array. The reduction in detected scatter achieved with this geometry was expected to provide an increase in image contrast. Vessel contrast was evaluated from images of a phantom containing iodinated tubes. The vessels were inserted into an acrylic stack to provide a patient-mimicking scattering medium. Vessel diameter ranged from 0.3 to 3.1 mm. Images were acquired at 100 kVp with the SBDX and II/TV systems and averaged to reduce x-ray noise. The II/TV system was operated in the 6-in. image intensifier mode with an anti-scatter grid. The increase in contrast in the SBDX images, expressed as a ratio of the measured SBDX and II/TV contrasts, ranged from 1.63 to 1.79 for individual vessels. This agreed well with a prediction of the contrast improvement ratio for this experiment, based on measurements of the scatter fraction, object-plane line spread functions, and consideration of the source spectrum and detector absorption properties. The predicted contrast improvement ratio for SBDX relative to II/TV images was 1.62 to 1.77

  3. Tumor Vessel Compression Hinders Perfusion of Ultrasonographic Contrast Agents

    Directory of Open Access Journals (Sweden)

    Mirco Galiè

    2005-05-01

    Full Text Available Contrast-enhanced ultrasound (CEUS is an advanced approach to in vivo assessment of tumor vascularity and is being increasingly adopted in clinical oncology. It is based on 1- to 10 μm-sized gas microbubbles, which can cross the capillary beds of the lungs and are effective echo enhancers. It is known that high cell density, high transendothelial fluid exchange, and poorly functioning lymphatic circulation all provoke solid stress, which compresses vessels and drastically reduces tumor blood flow. Given their size, we supposed that the perfusion of microbubbles is affected by anatomic features of tumor vessels more than are contrast agents traditionally used in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI. Here, we compared dynamic information obtained from CEUS and DCE-MRI on two experimental tumor models exhibiting notable differences in vessel anatomy. We found that tumors with small, flattened vessels show a much higher resistance to microbubble perfusion than to MRI contrast agents, and appear scarcely vascularized at CEUS examination, despite vessel volume adequate for normal function. Thus, whereas CEUS alone could induce incorrect diagnosis when tumors have small or collapsed vessels, integrated analysis using CEUS and DCE-MRI allows in vivo identification of tumors with a vascular profile frequently associated with malignant phenotypes.

  4. Smooth muscle cell recruitment to lymphatic vessels requires PDGFB and impacts vessel size but not identity.

    Science.gov (United States)

    Wang, Yixin; Jin, Yi; Mäe, Maarja Andaloussi; Zhang, Yang; Ortsäter, Henrik; Betsholtz, Christer; Mäkinen, Taija; Jakobsson, Lars

    2017-10-01

    Tissue fluid drains through blind-ended lymphatic capillaries, via smooth muscle cell (SMC)-covered collecting vessels into venous circulation. Both defective SMC recruitment to collecting vessels and ectopic recruitment to lymphatic capillaries are thought to contribute to vessel failure, leading to lymphedema. However, mechanisms controlling lymphatic SMC recruitment and its role in vessel maturation are unknown. Here, we demonstrate that platelet-derived growth factor B (PDGFB) regulates lymphatic SMC recruitment in multiple vascular beds. PDGFB is selectively expressed by lymphatic endothelial cells (LECs) of collecting vessels. LEC-specific deletion of Pdgfb prevented SMC recruitment causing dilation and failure of pulsatile contraction of collecting vessels. However, vessel remodelling and identity were unaffected. Unexpectedly, Pdgfb overexpression in LECs did not induce SMC recruitment to capillaries. This was explained by the demonstrated requirement of PDGFB extracellular matrix (ECM) retention for lymphatic SMC recruitment, and the low presence of PDGFB-binding ECM components around lymphatic capillaries. These results demonstrate the requirement of LEC-autonomous PDGFB expression and retention for SMC recruitment to lymphatic vessels, and suggest an ECM-controlled checkpoint that prevents SMC investment of capillaries, which is a common feature in lymphedematous skin. © 2017. Published by The Company of Biologists Ltd.

  5. Effect of Matrix Size on the Image Quality of Ultra-high-resolution CT of the Lung: Comparison of 512 × 512, 1024 × 1024, and 2048 × 2048.

    Science.gov (United States)

    Hata, Akinori; Yanagawa, Masahiro; Honda, Osamu; Kikuchi, Noriko; Miyata, Tomo; Tsukagoshi, Shinsuke; Uranishi, Ayumi; Tomiyama, Noriyuki

    2018-01-16

    This study aimed to assess the effect of matrix size on the spatial resolution and image quality of ultra-high-resolution computed tomography (U-HRCT). Slit phantoms and 11 cadaveric lungs were scanned on U-HRCT. Slit phantom scans were reconstructed using a 20-mm field of view (FOV) with 1024 matrix size and a 320-mm FOV with 512, 1024, and 2048 matrix sizes. Cadaveric lung scans were reconstructed using 512, 1024, and 2048 matrix sizes. Three observers subjectively scored the images on a three-point scale (1 = worst, 3 = best), in terms of overall image quality, noise, streak artifact, vessel, bronchi, and image findings. The median score of the three observers was evaluated by Wilcoxon signed-rank test with Bonferroni correction. Noise was measured quantitatively and evaluated with the Tukey test. A P value of matrix had the highest resolution and was significantly better than the 1024 matrix in terms of overall quality, solid nodule, ground-glass opacity, emphysema, intralobular reticulation, honeycombing, and clarity of vessels (P matrix (P matrix size maintained the spatial resolution and improved the image quality and assessment of lung diseases, despite an increase in image noise, when compared to a 512 matrix size. Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  6. Unique identification code for medical fundus images using blood vessel pattern for tele-ophthalmology applications.

    Science.gov (United States)

    Singh, Anushikha; Dutta, Malay Kishore; Sharma, Dilip Kumar

    2016-10-01

    Identification of fundus images during transmission and storage in database for tele-ophthalmology applications is an important issue in modern era. The proposed work presents a novel accurate method for generation of unique identification code for identification of fundus images for tele-ophthalmology applications and storage in databases. Unlike existing methods of steganography and watermarking, this method does not tamper the medical image as nothing is embedded in this approach and there is no loss of medical information. Strategic combination of unique blood vessel pattern and patient ID is considered for generation of unique identification code for the digital fundus images. Segmented blood vessel pattern near the optic disc is strategically combined with patient ID for generation of a unique identification code for the image. The proposed method of medical image identification is tested on the publically available DRIVE and MESSIDOR database of fundus image and results are encouraging. Experimental results indicate the uniqueness of identification code and lossless recovery of patient identity from unique identification code for integrity verification of fundus images. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  7. Direct bolus imaging of cervical blood vessels by means of MRI

    International Nuclear Information System (INIS)

    Satoh, Toshihiko; Fujioka, Mutsuhisa; Watari, Tsutomu; Nishimura, Gen; Matsumoto, Toshihiko; Washiya, Sumio; Inoue, Kiyoshi; Horita, Masatoshi; Shimizu, Kohji.

    1991-01-01

    Direct bolus imaging (DBI) is one of the non-invasive method for flow measurements which is based on the bolus tracking technique. DBI permits the direct visualization of flow velocity profiles and vessel band width. We performed screening for cervical vessel disease in patients with vertigo by means of DBI. MR system used here was 0.5 T superconducting imager-SMT-50A (Shimazu Co. Ltd). Pulse sequence parameters were TR= 60 ms, TE= 50 ms, NEX= 1, acquisition matrix; 128 x 256, slice thickness= 5 mm, with cardiac gating. Pulse sequence employed a slice selective RF pulse at the level of C5 vertebral body to tag a disk of fluid perpendicular to the direction of flow, followed by a gradient reforcussed echo. We evaluated each peak high and band width of the common-carotid arteries and the vertebral arteries. Seventy nine of 83 cases had optimal examinations. Abnormal findings of DBI were seen in 15 of 79 cases, (including 2 of subclavian steal syndrome, 1 of carotid obstruction, 5 of vertebral obstruction, 1 of basilar artery obstruction, and 6 of hypoplasia of vertebral artery). The abnormal findings of DBI were well correlated with those of angiographic examinations. We concluded that DBI was suitable to the screening for cervical vessel diseases in patients with vertigo, and should be added to the routine MR studies. (author)

  8. Assessment of the significance of coronary collateral vessel by using thallium-201 myocardial imaging

    International Nuclear Information System (INIS)

    Kanoh, Yasushi; Shiotani, Hideyuki; Fukuzaki, Hisashi; Maeda, Kazumi.

    1988-01-01

    For functional assessment of coronary collateral vessels, twenty-three patients with effort angina pectoris who had total coronary obstruction were studied. The patients were divided depending on the degree of development of collateral vessels into two groups, i.e. good collateral group I (n = 13) and poor collateral group II (n = 10). Thallium-201 scan was performed immediately (Ex-1 image), 20 minutes (Ex-2 image) after exercise and after nitroglycerin administration (NTG image) respectively. In all images, the relative percent activity of thallium-201 in the collateral-dependent ischemic area to the normal myocardium were calculated and were compaired between two groups. Relative percent activities in group I and II were as follows : Ex-1 image ; 75.8 ± 3.5 % vs. 77.2 ± 2.9 % (NS), Ex-2 images ; 85.3 ± 4.5 % vs. 79.3 ± 3.9 % (p < 0.005), NTG image ; 97.3 ± 3.1 % vs. 96.4 ± 5.2 % (NS). From these results, it was elucidated that good collateral induced early partial redistribution in its perfusion area, suggesting that good collateral circulation may provide rapid recovery from myocardial ischemia. (author)

  9. The Effect of Pulsatile Flow on bMSC-Derived Endothelial-Like Cells in a Small-Sized Artificial Vessel Made by 3-Dimensional Bioprinting

    Directory of Open Access Journals (Sweden)

    Kang Woog Lee

    2018-01-01

    Full Text Available Replacement of small-sized vessels is still challenging. This study is aimed at investigating the possibility of small-sized artificial vessels made by 3-dimensional bioprinting and the effect of pulsatile flow on bMSC-derived endothelial-like cells. Cells were harvested from rabbit bone marrow and primary cultured with or without growth factors. Endothelial differentiation was confirmed by the Matrigel tube formation assay, Western blot, and qRT-PCR. In addition, embedment of endothelial-like cells in an artificial vessel was made by 3-dimensional bioprinting, and the pulsatile flow was performed. For pumped and nonpumped groups, qRT-PCR was performed on CD31 and VE-cadherin gene expression. Endothelial-like cells showed increased gene expression of CD31 and VE-cadherin, and tube formation is observed at each week. Endothelial-like cells grow well in a small-sized artificial vessel made by 3-dimensional bioprinting and even express higher endothelial cell markers when they undergo pulsatile flow condition. Moreover, the pulsatile flow condition gives a positive effect for cell observation not only on the sodium alginate hydrogel layer but also on the luminal surface of the artificial vessel wall. We have developed an artificial vessel, which is a mixture of cells and carriers using a 3-dimensional bioprinting method, and applied pulsatile flow using a peristaltic pump, and we also demonstrated cell growth and differentiation into endothelial cells. This study suggests guidelines regarding a small-sized artificial vessel in the field of tissue engineering.

  10. MR imaging of the cranial nerves and the intracranial vessels using 3D-SPGR

    International Nuclear Information System (INIS)

    Hosoya, Takaaki; Sato, Nami; Yamaguchi, Koichi; Sugai, Yukio; Ogushi, Masatoshi; Kubota, Hisashi

    1992-01-01

    MR angiography (MRA) has developed rapidly, but it is still insufficient to demonstrate the detail of the intracranial vascular anatomy. We found that original images of MRA render more information than MRA images about not only intracranial vessels but also cranial nerves. We have tried to demonstrate cranial nerves and intracranial vessels on 26 patients and evaluated using real time reformation of original images of MRA. MR images were obtained by SPGR (3DFT) after injection of Gd-DTPA. The optic nerve, the oculomotor nerve, the trigeminal nerve, the facial nerve and the vestibulocochlear nerve were visualized clearly on almost patients and detectabilities of these nerves were 100%, 98%, 100%, 94% and 100%, respectively. The abducent nerve was also detectable in 76%. The trochlear nerve, which could not be observed by any modality, was detected at prepontine cistern in 10%. Arteries around brain stem such as the superior cerebellar artery (SCA), the anterior inferior cerebellar artery (AICA), the posterior inferior cerebellar artery (PICA) and the posterior communicating artery (PcomA) were clearly visible, and branching of these arteries and anatomical detail were completely coincide with angiogram on 12 patients. The basal vein of Rosenthal and the petrosal vein were confirmed in 100% and their anastomose were demonstrated obviously. We concluded that this method was extremely useful to observe cranial nerves and intracranial small vessels. (author)

  11. Imaging transient blood vessel fusion events in zebrafish by correlative volume electron microscopy.

    Directory of Open Access Journals (Sweden)

    Hannah E J Armer

    Full Text Available The study of biological processes has become increasingly reliant on obtaining high-resolution spatial and temporal data through imaging techniques. As researchers demand molecular resolution of cellular events in the context of whole organisms, correlation of non-invasive live-organism imaging with electron microscopy in complex three-dimensional samples becomes critical. The developing blood vessels of vertebrates form a highly complex network which cannot be imaged at high resolution using traditional methods. Here we show that the point of fusion between growing blood vessels of transgenic zebrafish, identified in live confocal microscopy, can subsequently be traced through the structure of the organism using Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM and Serial Block Face/Scanning Electron Microscopy (SBF/SEM. The resulting data give unprecedented microanatomical detail of the zebrafish and, for the first time, allow visualization of the ultrastructure of a time-limited biological event within the context of a whole organism.

  12. Tumor Vessel Compression Hinders Perfusion of Ultrasonographic Contrast Agents1

    Science.gov (United States)

    Galiè, Mirco; D'Onofrio, Mirko; Montani, Maura; Amici, Augusto; Calderan, Laura; Marzola, Pasquina; Benati, Donatella; Merigo, Flavia; Marchini, Cristina; Sbarbati, Andrea

    2005-01-01

    Abstract Contrast-enhanced ultrasound (CEUS) is an advanced approach to in vivo assessment of tumor vascularity and is being increasingly adopted in clinical oncology. It is based on 1- to 10 µm-sized gas microbubbles, which can cross the capillary beds of the lungs and are effective echo enhancers. It is known that high cell density, high transendothelial fluid exchange, and poorly functioning lymphatic circulation all provoke solid stress, which compresses vessels and drastically reduces tumor blood flow. Given their size, we supposed that the perfusion of microbubbles is affected by anatomic features of tumor vessels more than are contrast agents traditionally used in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Here, we compared dynamic information obtained from CEUS and DCE-MRI on two experimental tumor models exhibiting notable differences in vessel anatomy. We found that tumors with small, flattened vessels show a much higher resistance to microbubble perfusion than to MRI contrast agents, and appear scarcely vascularized at CEUS examination, despite vessel volume adequate for normal function. Thus, whereas CEUS alone could induce incorrect diagnosis when tumors have small or collapsed vessels, integrated analysis using CEUS and DCE-MRI allows in vivo identification of tumors with a vascular profile frequently associated with malignant phenotypes. PMID:15967105

  13. Microparticle image velocimetry approach to flow measurements in isolated contracting lymphatic vessels.

    Science.gov (United States)

    Margaris, Konstantinos N; Nepiyushchikh, Zhanna; Zawieja, David C; Moore, James; Black, Richard A

    2016-02-01

    We describe the development of an optical flow visualization method for resolving the flow velocity vector field in lymphatic vessels in vitro. The aim is to develop an experimental protocol for accurately estimating flow parameters, such as flow rate and shear stresses, with high spatial and temporal resolution. Previous studies in situ have relied on lymphocytes as tracers, but their low density resulted in a reduced spatial resolution whereas the assumption that the flow was fully developed in order to determine the flow parameters of interest may not be valid, especially in the vicinity of the valves, where the flow is undoubtedly more complex. To overcome these issues, we have applied the time-resolved microparticle image velocimetry (μ -PIV) technique, a well-established method that can provide increased spatial and temporal resolution that this transient flow demands. To that end, we have developed a custom light source, utilizing high-power light-emitting diodes, and associated control and image processing software. This paper reports the performance of the system and the results of a series of preliminary experiments performed on vessels isolated from rat mesenteries, demonstrating, for the first time, the successful application of the μ -PIV technique in these vessels.

  14. Size measurement of radioactive aerosol particles in intense radiation fields using wire screens and imaging plates

    Energy Technology Data Exchange (ETDEWEB)

    Oki, Yuichi; Tanaka, Toru; Takamiya, Koichi; Ishi, Yoshihiro; UesugI, Tomonori; Kuriyama, Yasutoshi; Sakamoto, Masaaki; Ohtsuki, Tsutomu [Kyoto University Research Reactor Institute, Osaka (Japan); Nitta, Shinnosuke [Graduate School of Engineering, Kyoto University, Kyoto (Japan); Osada, Naoyuki [Advanced Science Research Center, Okayama University, Okayama (Japan)

    2016-09-15

    Very fine radiation-induced aerosol particles are produced in intense radiation fields, such as high-intensity accelerator rooms and containment vessels such as those in the Fukushima Daiichi nuclear power plant (FDNPP). Size measurement of the aerosol particles is very important for understanding the behavior of radioactive aerosols released in the FDNPP accident and radiation safety in high-energy accelerators. A combined technique using wire screens and imaging plates was developed for size measurement of fine radioactive aerosol particles smaller than 100 nm in diameter. This technique was applied to the radiation field of a proton accelerator room, in which radioactive atoms produced in air during machine operation are incorporated into radiation-induced aerosol particles. The size of 11C-bearing aerosol particles was analyzed using the wire screen technique in distinction from other positron emitters in combination with a radioactive decay analysis. The size distribution for 11C-bearing aerosol particles was found to be ca. 70 μm in geometric mean diameter. The size was similar to that for 7Be-bearing particles obtained by a Ge detector measurement, and was slightly larger than the number-based size distribution measured with a scanning mobility particle sizer. The particle size measuring method using wire screens and imaging plates was successfully applied to the fine aerosol particles produced in an intense radiation field of a proton accelerator. This technique is applicable to size measurement of radioactive aerosol particles produced in the intense radiation fields of radiation facilities.

  15. Automated detection of kinks from blood vessels for optic cup segmentation in retinal images

    Science.gov (United States)

    Wong, D. W. K.; Liu, J.; Lim, J. H.; Li, H.; Wong, T. Y.

    2009-02-01

    The accurate localization of the optic cup in retinal images is important to assess the cup to disc ratio (CDR) for glaucoma screening and management. Glaucoma is physiologically assessed by the increased excavation of the optic cup within the optic nerve head, also known as the optic disc. The CDR is thus an important indicator of risk and severity of glaucoma. In this paper, we propose a method of determining the cup boundary using non-stereographic retinal images by the automatic detection of a morphological feature within the optic disc known as kinks. Kinks are defined as the bendings of small vessels as they traverse from the disc to the cup, providing physiological validation for the cup boundary. To detect kinks, localized patches are first generated from a preliminary cup boundary obtained via level set. Features obtained using edge detection and wavelet transform are combined using a statistical approach rule to identify likely vessel edges. The kinks are then obtained automatically by analyzing the detected vessel edges for angular changes, and these kinks are subsequently used to obtain the cup boundary. A set of retinal images from the Singapore Eye Research Institute was obtained to assess the performance of the method, with each image being clinically graded for the CDR. From experiments, when kinks were used, the error on the CDR was reduced to less than 0.1 CDR units relative to the clinical CDR, which is within the intra-observer variability of 0.2 CDR units.

  16. Image Size Variation Influence on Corrupted and Non-viewable BMP Image

    Science.gov (United States)

    Azmi, Tengku Norsuhaila T.; Azma Abdullah, Nurul; Rahman, Nurul Hidayah Ab; Hamid, Isredza Rahmi A.; Chai Wen, Chuah

    2017-08-01

    Image is one of the evidence component seek in digital forensics. Joint Photographic Experts Group (JPEG) format is most popular used in the Internet because JPEG files are very lossy and easy to compress that can speed up Internet transmitting processes. However, corrupted JPEG images are hard to recover due to the complexities of determining corruption point. Nowadays Bitmap (BMP) images are preferred in image processing compared to another formats because BMP image contain all the image information in a simple format. Therefore, in order to investigate the corruption point in JPEG, the file is required to be converted into BMP format. Nevertheless, there are many things that can influence the corrupting of BMP image such as the changes of image size that make the file non-viewable. In this paper, the experiment indicates that the size of BMP file influences the changes in the image itself through three conditions, deleting, replacing and insertion. From the experiment, we learnt by correcting the file size, it can able to produce a viewable file though partially. Then, it can be investigated further to identify the corruption point.

  17. Estimation of vessel diameter and blood flow dynamics from laser speckle images

    DEFF Research Database (Denmark)

    Postnov, Dmitry D.; Tuchin, Valery V.; Sosnovtseva, Olga

    2016-01-01

    Laser speckle imaging is a rapidly developing method to study changes of blood velocity in the vascular networks. However, to assess blood flow and vascular responses it is crucial to measure vessel diameter in addition to blood velocity dynamics. We suggest an algorithm that allows for dynamical...

  18. Comparison of vessel enhancement algorithms applied to time-of-flight MRA images for cerebrovascular segmentation.

    Science.gov (United States)

    Phellan, Renzo; Forkert, Nils D

    2017-11-01

    Vessel enhancement algorithms are often used as a preprocessing step for vessel segmentation in medical images to improve the overall segmentation accuracy. Each algorithm uses different characteristics to enhance vessels, such that the most suitable algorithm may vary for different applications. This paper presents a comparative analysis of the accuracy gains in vessel segmentation generated by the use of nine vessel enhancement algorithms: Multiscale vesselness using the formulas described by Erdt (MSE), Frangi (MSF), and Sato (MSS), optimally oriented flux (OOF), ranking orientations responses path operator (RORPO), the regularized Perona-Malik approach (RPM), vessel enhanced diffusion (VED), hybrid diffusion with continuous switch (HDCS), and the white top hat algorithm (WTH). The filters were evaluated and compared based on time-of-flight MRA datasets and corresponding manual segmentations from 5 healthy subjects and 10 patients with an arteriovenous malformation. Additionally, five synthetic angiographic datasets with corresponding ground truth segmentation were generated with three different noise levels (low, medium, and high) and also used for comparison. The parameters for each algorithm and subsequent segmentation were optimized using leave-one-out cross evaluation. The Dice coefficient, Matthews correlation coefficient, area under the ROC curve, number of connected components, and true positives were used for comparison. The results of this study suggest that vessel enhancement algorithms do not always lead to more accurate segmentation results compared to segmenting nonenhanced images directly. Multiscale vesselness algorithms, such as MSE, MSF, and MSS proved to be robust to noise, while diffusion-based filters, such as RPM, VED, and HDCS ranked in the top of the list in scenarios with medium or no noise. Filters that assume tubular-shapes, such as MSE, MSF, MSS, OOF, RORPO, and VED show a decrease in accuracy when considering patients with an AVM

  19. Ultrasonographic Examination of Some Vessels in Dogs and the Characteristics of Blood Flow in These Vessels

    Directory of Open Access Journals (Sweden)

    Figurová M.

    2017-12-01

    Full Text Available The examination by Doppler ultrasonography provides haemodynamic information about blood flow velocity in a respective vessel. It specifies high- and lowresistance flow patterns. The aim of our study was to record the flow in a. carotis communis, a. femoralis and aa. renales in 16 adult clinically healthy dogs of small and medium size; characterize the types of vessels and also determine the pulsatility index (PI and the resistive index (RI of these vessels. The a. femoralis is a high-resistance vessel with a pronounced three-peak waveform. The aa. renales gives a typical picture of a low-resistance flow pattern. The characteristics of a. carotis communis involves different images of its branches a. carotis interna and a. carotis externa. In the investigated groups we observed a medium degree of pulsatility (atypical highresistance flow pattern with an absence of reverse flow. The mean measured values of indices for a. carotis communis were: left side PI 1.824 and RI 0.742; right side PI 1.891 and RI 0.746, and for aa. renales: PI 1.366 ± 0.04 and RI 0.684 ± 0.05.

  20. High-resolution MRI vessel wall imaging: spatial and temporal patterns of reversible cerebral vasoconstriction syndrome and central nervous system vasculitis.

    Science.gov (United States)

    Obusez, E C; Hui, F; Hajj-Ali, R A; Cerejo, R; Calabrese, L H; Hammad, T; Jones, S E

    2014-08-01

    High-resolution MR imaging is an emerging tool for evaluating intracranial artery disease. It has an advantage of defining vessel wall characteristics of intracranial vascular diseases. We investigated high-resolution MR imaging arterial wall characteristics of CNS vasculitis and reversible cerebral vasoconstriction syndrome to determine wall pattern changes during a follow-up period. We retrospectively reviewed 3T-high-resolution MR imaging vessel wall studies performed on 26 patients with a confirmed diagnosis of CNS vasculitis and reversible cerebral vasoconstriction syndrome during a follow-up period. Vessel wall imaging protocol included black-blood contrast-enhanced T1-weighted sequences with fat suppression and a saturation band, and time-of-flight MRA of the circle of Willis. Vessel wall characteristics including enhancement, wall thickening, and lumen narrowing were collected. Thirteen patients with CNS vasculitis and 13 patients with reversible cerebral vasoconstriction syndrome were included. In the CNS vasculitis group, 9 patients showed smooth, concentric wall enhancement and thickening; 3 patients had smooth, eccentric wall enhancement and thickening; and 1 patient was without wall enhancement and thickening. Six of 13 patients had follow-up imaging; 4 patients showed stable smooth, concentric enhancement and thickening; and 2 patients had resoluton of initial imaging findings. In the reversible cerebral vasoconstriction syndrome group, 10 patients showed diffuse, uniform wall thickening with negligible-to-mild enhancement. Nine patients had follow-up imaging, with 8 patients showing complete resolution of the initial findings. Postgadolinium 3T-high-resolution MR imaging appears to be a feasible tool in differentiating vessel wall patterns of CNS vasculitis and reversible cerebral vasoconstriction syndrome changes during a follow-up period. © 2014 by American Journal of Neuroradiology.

  1. Automated vessel segmentation using cross-correlation and pooled covariance matrix analysis.

    Science.gov (United States)

    Du, Jiang; Karimi, Afshin; Wu, Yijing; Korosec, Frank R; Grist, Thomas M; Mistretta, Charles A

    2011-04-01

    Time-resolved contrast-enhanced magnetic resonance angiography (CE-MRA) provides contrast dynamics in the vasculature and allows vessel segmentation based on temporal correlation analysis. Here we present an automated vessel segmentation algorithm including automated generation of regions of interest (ROIs), cross-correlation and pooled sample covariance matrix analysis. The dynamic images are divided into multiple equal-sized regions. In each region, ROIs for artery, vein and background are generated using an iterative thresholding algorithm based on the contrast arrival time map and contrast enhancement map. Region-specific multi-feature cross-correlation analysis and pooled covariance matrix analysis are performed to calculate the Mahalanobis distances (MDs), which are used to automatically separate arteries from veins. This segmentation algorithm is applied to a dual-phase dynamic imaging acquisition scheme where low-resolution time-resolved images are acquired during the dynamic phase followed by high-frequency data acquisition at the steady-state phase. The segmented low-resolution arterial and venous images are then combined with the high-frequency data in k-space and inverse Fourier transformed to form the final segmented arterial and venous images. Results from volunteer and patient studies demonstrate the advantages of this automated vessel segmentation and dual phase data acquisition technique. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Automated Measurement Of The Density Of Vessels On Whole Slide Images Of Paediatric Brain Tumours

    Directory of Open Access Journals (Sweden)

    Christophe Deroulers

    2016-06-01

    Only a few parameters have to be chosen, once and for all samples (e.g., the minimal acceptable size of a blood vessel fragment, which makes the method more robust than assessment by a (panel of human expert(s. The automatic calibration steps enable one to deal with a heterogeneous set of slides (e.g., slight differences in background colour and staining. The method uses only open-source software. It is easy to extend or improve and not tight to a single immunomarker. We applied the method to 129 paediatric brain tumours of 8 different types and 3 locations (posterior fossa, thalamus, hemispheres — 185 samples in total. For each patient, the density of microvessels in the sample is compared to the cerebral blood flow as assessed by preoperative perfusion-weighted-imaging using arterial-spin-labeling. We find a good correlation between microvascular density, MRI data and tumour grading. The microvascular density is broadly distributed among the samples. Visualisation in a web browser is slightly more fluid when images are uploaded in the DeepZoom format rather than as pyramidal TIFF images, but the former consumes roughly 20 times more disk space and needs the transfer of a very large number of files after each modification, which is less tractable.

  3. Non-gated vessel wall imaging of the internal carotid artery using radial scanning and fast spin echo sequence. Evaluation of vessel signal intensity by flow rate at 3.0 tesla

    International Nuclear Information System (INIS)

    Nakamura, Manami; Makabe, Takeshi; Ichikawa, Masaki; Hatakeyama, Ryohei; Sugimori, Hiroyuki; Sakata, Motomichi

    2013-01-01

    Vessel wall imaging using radial scanning does not use a blood flow suppression pulse with gated acquisition. It has been proposed that there may not be a flow void effect if the flow rate is slow; however, this has yet to be empirically tested. To clarify the relationship between the signal intensity of the vessel lumen and the blood flow rate in a flow phantom, we investigated the usefulness of vessel wall imaging at 3.0 tesla (T). We measured the signal intensity while changing the flow rate in the flow phantom. Radial scanning at 1.5 T showed sufficient flow voids at above medium flow rates. There was no significant difference in lumen signal intensity at the carotid artery flow rate. The signal intensity of the vessel lumen decreased sufficiently using the radial scan method at 3.0 T. We thus obtained sufficient flow void effects at the carotid artery flow rate. We conclude this technique to be useful for evaluating plaque if high contrast can be maintained for fixed tissue (such as plaque) and the vessel lumen. (author)

  4. Automated registration of multispectral MR vessel wall images of the carotid artery

    Energy Technology Data Exchange (ETDEWEB)

    Klooster, R. van ' t; Staring, M.; Reiber, J. H. C.; Lelieveldt, B. P. F.; Geest, R. J. van der, E-mail: rvdgeest@lumc.nl [Department of Radiology, Division of Image Processing, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Klein, S. [Department of Radiology and Department of Medical Informatics, Biomedical Imaging Group Rotterdam, Erasmus MC, Rotterdam 3015 GE (Netherlands); Kwee, R. M.; Kooi, M. E. [Department of Radiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht 6202 AZ (Netherlands)

    2013-12-15

    Purpose: Atherosclerosis is the primary cause of heart disease and stroke. The detailed assessment of atherosclerosis of the carotid artery requires high resolution imaging of the vessel wall using multiple MR sequences with different contrast weightings. These images allow manual or automated classification of plaque components inside the vessel wall. Automated classification requires all sequences to be in alignment, which is hampered by patient motion. In clinical practice, correction of this motion is performed manually. Previous studies applied automated image registration to correct for motion using only nondeformable transformation models and did not perform a detailed quantitative validation. The purpose of this study is to develop an automated accurate 3D registration method, and to extensively validate this method on a large set of patient data. In addition, the authors quantified patient motion during scanning to investigate the need for correction. Methods: MR imaging studies (1.5T, dedicated carotid surface coil, Philips) from 55 TIA/stroke patients with ipsilateral <70% carotid artery stenosis were randomly selected from a larger cohort. Five MR pulse sequences were acquired around the carotid bifurcation, each containing nine transverse slices: T1-weighted turbo field echo, time of flight, T2-weighted turbo spin-echo, and pre- and postcontrast T1-weighted turbo spin-echo images (T1W TSE). The images were manually segmented by delineating the lumen contour in each vessel wall sequence and were manually aligned by applying throughplane and inplane translations to the images. To find the optimal automatic image registration method, different masks, choice of the fixed image, different types of the mutual information image similarity metric, and transformation models including 3D deformable transformation models, were evaluated. Evaluation of the automatic registration results was performed by comparing the lumen segmentations of the fixed image and

  5. Automated registration of multispectral MR vessel wall images of the carotid artery

    International Nuclear Information System (INIS)

    Klooster, R. van 't; Staring, M.; Reiber, J. H. C.; Lelieveldt, B. P. F.; Geest, R. J. van der; Klein, S.; Kwee, R. M.; Kooi, M. E.

    2013-01-01

    Purpose: Atherosclerosis is the primary cause of heart disease and stroke. The detailed assessment of atherosclerosis of the carotid artery requires high resolution imaging of the vessel wall using multiple MR sequences with different contrast weightings. These images allow manual or automated classification of plaque components inside the vessel wall. Automated classification requires all sequences to be in alignment, which is hampered by patient motion. In clinical practice, correction of this motion is performed manually. Previous studies applied automated image registration to correct for motion using only nondeformable transformation models and did not perform a detailed quantitative validation. The purpose of this study is to develop an automated accurate 3D registration method, and to extensively validate this method on a large set of patient data. In addition, the authors quantified patient motion during scanning to investigate the need for correction. Methods: MR imaging studies (1.5T, dedicated carotid surface coil, Philips) from 55 TIA/stroke patients with ipsilateral <70% carotid artery stenosis were randomly selected from a larger cohort. Five MR pulse sequences were acquired around the carotid bifurcation, each containing nine transverse slices: T1-weighted turbo field echo, time of flight, T2-weighted turbo spin-echo, and pre- and postcontrast T1-weighted turbo spin-echo images (T1W TSE). The images were manually segmented by delineating the lumen contour in each vessel wall sequence and were manually aligned by applying throughplane and inplane translations to the images. To find the optimal automatic image registration method, different masks, choice of the fixed image, different types of the mutual information image similarity metric, and transformation models including 3D deformable transformation models, were evaluated. Evaluation of the automatic registration results was performed by comparing the lumen segmentations of the fixed image and

  6. Comparison of exercise electrocardiography and quantitative thallium imaging for one-vessel coronary artery disease

    International Nuclear Information System (INIS)

    Kaul, S.; Kiess, M.; Liu, P.; Guiney, T.E.; Pohost, G.M.; Okada, R.D.; Boucher, C.A.

    1985-01-01

    The relative value of exercise electrocardiography and computer analyzed thallium-201 imaging was compared in 124 patients with 1-vessel coronary artery disease (CAD). Of these, 78 had left anterior descending (LAD), 32 right and 14 left circumflex (LC) CAD. In patients with no previous myocardial infarction (MI), thallium imaging was more sensitive than the electrocardiogram (78% vs 64%, p less than 0.01), but in patients with previous MI, sensitivity was similar. Further, thallium imaging was more sensitive only in LAD and LC disease. Redistribution was compared with ST-segment depression as a marker of ischemia. Only in patients with prior MI (76% vs 44%, p less than 0.01) and only in LC and right CAD did redistribution occur more often than ST depression. Thallium imaging was more accurate in localizing stenoses than the electrocardiogram (p less than 0.001), but did not always correctly predict coronary anatomy. Septal thallium defects were associated with LAD disease in 84%, inferior defects with right CAD in 40% and posterolateral lesion defects with LC CAD in 22%. The results indicate the overall superiority of thallium imaging in 1-vessel CAD compared with exercise electrocardiography; however, there is a wide spectrum of extent and location of perfusion defects associated with each coronary artery. Thallium imaging complements coronary angiography by demonstrating the functional impact of CAD on myocardial perfusion

  7. Occupational Safety and Health Conditions Aboard Small- and Medium-Size Fishing Vessels: Differences among Age Groups.

    Science.gov (United States)

    Zytoon, Mohamed A; Basahel, Abdulrahman M

    2017-02-24

    Although marine fishing is one of the most hazardous occupations, research on the occupational safety and health (OSH) conditions aboard marine fishing vessels is scarce. For instance, little is known about the working conditions of vulnerable groups such as young and aging fishermen. The objective of the current paper is to study the OSH conditions of young and aging fishermen compared to middle-aged fishermen in the small- and medium-size (SM) marine fishing sector. A cross-sectional study was designed, and 686 fishermen working aboard SM fishing vessels were interviewed to collect information about their safety and health. The associations of physical and psychosocial work conditions with safety and health outcomes, e.g., injuries, illnesses and job satisfaction, are presented. The results of the current study can be utilized in the design of effective accident prevention and OSH training programs for the three age groups and in the regulation of working conditions aboard fishing vessels.

  8. WE-E-18A-10: Comparison of Patient Dose and Vessel Visibility Between Antiscatter Grid Removal and Lower Angiographic Radiation Dose Settings for Pediatric Imaging: A Preclinical Investigation

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, K; Nachabe, R; Racadio, J [Children' s Hospital Medical Center, Cincinnati, OH (United States)

    2014-06-15

    Purpose: To define an alternative to antiscatter grid (ASG) removal in angiographic systems which achieves similar patient dose reduction as ASG removal without degrading image quality during pediatric imaging. Methods: This study was approved by the local institution animal care and use committee (IACUC). Six different digital subtraction angiography settings were evaluated that altered the mAs, (100, 70, 50, 35, 25, 17.5% of reference mAs) with and without ASG. Three pigs of 5, 15, and 20 kg (9, 15, and 17 cm abdominal thickness; smaller than a newborn, average 3 yr old, and average 10 year old human abdomen respectively) were imaged using the six dose settings with and without ASG. Image quality was defined as the order of vessel branch that is visible relative to the injected vessel. Five interventional radiologists evaluated all images. Image quality and patient dose were statistically compared using analysis of variance and receiver operating curve (ROC) analysis to define the preferred dose level and use of ASG for a minimum visibility of 2nd or 3rd order branches of vessel visibility. Results: ASG grid removal reduces dose by 26% with reduced image quality. Only with the ASG present can 3rd order branches be visualized; 100% mAs is required for 9 cm pig while 70% mAs is adequate for the larger pigs. 2nd order branches can be visualized with ASG at 17.5% mAs for all three pig sizes. Without the ASG, 50%, 35% and 35% mAs is required for smallest to largest pig. Conclusion: Removing ASG reduces patient dose and image quality. Image quality can be improved with the ASG present while further reducing patient dose if an optimized radiographic technique is used. Rami Nachabe is an employee of Philips Health Care; Keith Strauss is a paid consultant of Philips Health Care.

  9. Influence of the weighing bar position in vessel on measurement of cement’s particle size distribution by using the buoyancy weighing-bar method

    Science.gov (United States)

    Tambun, R.; Sihombing, R. O.; Simanjuntak, A.; Hanum, F.

    2018-02-01

    The buoyancy weighing-bar method is a new simple and cost-effective method to determine the particle size distribution both settling and floating particle. In this method, the density change in a suspension due to particle migration is measured by weighing buoyancy against a weighing-bar hung in the suspension, and then the particle size distribution is calculated using the length of the bar and the time-course change in the mass of the bar. The apparatus of this method consists of a weighing-bar and an analytical balance with a hook for under-floor weighing. The weighing bar is used to detect the density change in suspension. In this study we investigate the influences of position of weighing bar in vessel on settling particle size distribution measurements of cement by using the buoyancy weighing-bar method. The vessel used in this experiment is graduated cylinder with the diameter of 65 mm and the position of weighing bar is in center and off center of vessel. The diameter of weighing bar in this experiment is 10 mm, and the kerosene is used as a dispersion liquids. The results obtained show that the positions of weighing bar in vessel have no significant effect on determination the cement’s particle size distribution by using buoyancy weighing-bar method, and the results obtained are comparable to those measured by using settling balance method.

  10. Unsupervised Retinal Vessel Segmentation Using Combined Filters.

    Directory of Open Access Journals (Sweden)

    Wendeson S Oliveira

    Full Text Available Image segmentation of retinal blood vessels is a process that can help to predict and diagnose cardiovascular related diseases, such as hypertension and diabetes, which are known to affect the retinal blood vessels' appearance. This work proposes an unsupervised method for the segmentation of retinal vessels images using a combined matched filter, Frangi's filter and Gabor Wavelet filter to enhance the images. The combination of these three filters in order to improve the segmentation is the main motivation of this work. We investigate two approaches to perform the filter combination: weighted mean and median ranking. Segmentation methods are tested after the vessel enhancement. Enhanced images with median ranking are segmented using a simple threshold criterion. Two segmentation procedures are applied when considering enhanced retinal images using the weighted mean approach. The first method is based on deformable models and the second uses fuzzy C-means for the image segmentation. The procedure is evaluated using two public image databases, Drive and Stare. The experimental results demonstrate that the proposed methods perform well for vessel segmentation in comparison with state-of-the-art methods.

  11. Personal identification based on blood vessels of retinal fundus images

    Science.gov (United States)

    Fukuta, Keisuke; Nakagawa, Toshiaki; Hayashi, Yoshinori; Hatanaka, Yuji; Hara, Takeshi; Fujita, Hiroshi

    2008-03-01

    Biometric technique has been implemented instead of conventional identification methods such as password in computer, automatic teller machine (ATM), and entrance and exit management system. We propose a personal identification (PI) system using color retinal fundus images which are unique to each individual. The proposed procedure for identification is based on comparison of an input fundus image with reference fundus images in the database. In the first step, registration between the input image and the reference image is performed. The step includes translational and rotational movement. The PI is based on the measure of similarity between blood vessel images generated from the input and reference images. The similarity measure is defined as the cross-correlation coefficient calculated from the pixel values. When the similarity is greater than a predetermined threshold, the input image is identified. This means both the input and the reference images are associated to the same person. Four hundred sixty-two fundus images including forty-one same-person's image pairs were used for the estimation of the proposed technique. The false rejection rate and the false acceptance rate were 9.9×10 -5% and 4.3×10 -5%, respectively. The results indicate that the proposed method has a higher performance than other biometrics except for DNA. To be used for practical application in the public, the device which can take retinal fundus images easily is needed. The proposed method is applied to not only the PI but also the system which warns about misfiling of fundus images in medical facilities.

  12. Small-target leak detection for a closed vessel via infrared image sequences

    Science.gov (United States)

    Zhao, Ling; Yang, Hongjiu

    2017-03-01

    This paper focus on a leak diagnosis and localization method based on infrared image sequences. Some problems on high probability of false warning and negative affect for marginal information are solved by leak detection. An experimental model is established for leak diagnosis and localization on infrared image sequences. The differential background prediction is presented to eliminate the negative affect of marginal information on test vessel based on a kernel regression method. A pipeline filter based on layering voting is designed to reduce probability of leak point false warning. A synthesize leak diagnosis and localization algorithm is proposed based on infrared image sequences. The effectiveness and potential are shown for developed techniques through experimental results.

  13. Study on closed pressure vessel test. Effect of heat rate, sample weight and vessel size on pressure rise due to thermal decomposition; Mippeigata atsuryoku yoki shiken ni kansuru kenkyu. Atsuryoku hassei kyodo ni oyobosu kanetsusokudo, shiryoryo oyobi youki saizu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Kenji.; Akutsu, Yoshiaki.; Arai, Mitsuru.; Tamura, Masamitsu. [The University of Tokyo, Tokyo (Japan). School of Engineering

    1999-02-28

    We have attempted to devise a new closed pressure vessel test apparatus in order to evaluate the violence of thermal decomposition of self-reactive materials and have examined some influencing factors, such as heat rate, sample weight, filling factor (sample weight/vessel size) and vessel size on Pmax (maximum pressure rise) and dP/dt (rate of pressure rise) due to their thermal decomposition. As a result, the following decreasing orders of Pmax and dP/dt were shown. Pmax: ADCA>BPZ>AIBN>TCP dP/dt: AIBN>BPZ>ADCA>TCP Moreover, Pmax was not almost influenced by heat rate, while dP/dt increased with an increase in heat rate in the case of BPZ. Pmax and dP/dt increased with an increase in sample weight and the degree of increase depended on the kinds of materials. In addition, it was shown that Pmax and dP/dt increased with an increase in vessel size at a constant filling factor. (author)

  14. An Automatic Cognitive Graph-Based Segmentation for Detection of Blood Vessels in Retinal Images

    Directory of Open Access Journals (Sweden)

    Rasha Al Shehhi

    2016-01-01

    Full Text Available This paper presents a hierarchical graph-based segmentation for blood vessel detection in digital retinal images. This segmentation employs some of perceptual Gestalt principles: similarity, closure, continuity, and proximity to merge segments into coherent connected vessel-like patterns. The integration of Gestalt principles is based on object-based features (e.g., color and black top-hat (BTH morphology and context and graph-analysis algorithms (e.g., Dijkstra path. The segmentation framework consists of two main steps: preprocessing and multiscale graph-based segmentation. Preprocessing is to enhance lighting condition, due to low illumination contrast, and to construct necessary features to enhance vessel structure due to sensitivity of vessel patterns to multiscale/multiorientation structure. Graph-based segmentation is to decrease computational processing required for region of interest into most semantic objects. The segmentation was evaluated on three publicly available datasets. Experimental results show that preprocessing stage achieves better results compared to state-of-the-art enhancement methods. The performance of the proposed graph-based segmentation is found to be consistent and comparable to other existing methods, with improved capability of detecting small/thin vessels.

  15. Feature-Based Retinal Image Registration Using D-Saddle Feature

    Directory of Open Access Journals (Sweden)

    Roziana Ramli

    2017-01-01

    Full Text Available Retinal image registration is important to assist diagnosis and monitor retinal diseases, such as diabetic retinopathy and glaucoma. However, registering retinal images for various registration applications requires the detection and distribution of feature points on the low-quality region that consists of vessels of varying contrast and sizes. A recent feature detector known as Saddle detects feature points on vessels that are poorly distributed and densely positioned on strong contrast vessels. Therefore, we propose a multiresolution difference of Gaussian pyramid with Saddle detector (D-Saddle to detect feature points on the low-quality region that consists of vessels with varying contrast and sizes. D-Saddle is tested on Fundus Image Registration (FIRE Dataset that consists of 134 retinal image pairs. Experimental results show that D-Saddle successfully registered 43% of retinal image pairs with average registration accuracy of 2.329 pixels while a lower success rate is observed in other four state-of-the-art retinal image registration methods GDB-ICP (28%, Harris-PIIFD (4%, H-M (16%, and Saddle (16%. Furthermore, the registration accuracy of D-Saddle has the weakest correlation (Spearman with the intensity uniformity metric among all methods. Finally, the paired t-test shows that D-Saddle significantly improved the overall registration accuracy of the original Saddle.

  16. An objective method to optimize the MR sequence set for plaque classification in carotid vessel wall images using automated image segmentation.

    Directory of Open Access Journals (Sweden)

    Ronald van 't Klooster

    Full Text Available A typical MR imaging protocol to study the status of atherosclerosis in the carotid artery consists of the application of multiple MR sequences. Since scanner time is limited, a balance has to be reached between the duration of the applied MR protocol and the quantity and quality of the resulting images which are needed to assess the disease. In this study an objective method to optimize the MR sequence set for classification of soft plaque in vessel wall images of the carotid artery using automated image segmentation was developed. The automated method employs statistical pattern recognition techniques and was developed based on an extensive set of MR contrast weightings and corresponding manual segmentations of the vessel wall and soft plaque components, which were validated by histological sections. Evaluation of the results from nine contrast weightings showed the tradeoff between scan duration and automated image segmentation performance. For our dataset the best segmentation performance was achieved by selecting five contrast weightings. Similar performance was achieved with a set of three contrast weightings, which resulted in a reduction of scan time by more than 60%. The presented approach can help others to optimize MR imaging protocols by investigating the tradeoff between scan duration and automated image segmentation performance possibly leading to shorter scanning times and better image interpretation. This approach can potentially also be applied to other research fields focusing on different diseases and anatomical regions.

  17. Elliptical local vessel density: a fast and robust quality metric for retinal images

    OpenAIRE

    Giancardo, L.; Abramoff, M.D.; Chaum, E.; Karnowski, T.P.; Meriaudeau, F.; Tobin, K.W.

    2008-01-01

    A great effort of the research community is geared towards the creation of an automatic screening system able to promptly detect diabetic retinopathy with the use of fundus cameras. In addition, there are some documented approaches for automatically judging the image quality. We propose a new set of features independent of field of view or resolution to describe the morphology of the patient's vessels. Our initial results suggest that these features can be used to estimate the image quality i...

  18. Fully integrated high-speed intravascular optical coherence tomography/near-infrared fluorescence structural/molecular imaging in vivo using a clinically available near-infrared fluorescence-emitting indocyanine green to detect inflamed lipid-rich atheromata in coronary-sized vessels.

    Science.gov (United States)

    Lee, Sunki; Lee, Min Woo; Cho, Han Saem; Song, Joon Woo; Nam, Hyeong Soo; Oh, Dong Joo; Park, Kyeongsoon; Oh, Wang-Yuhl; Yoo, Hongki; Kim, Jin Won

    2014-08-01

    Lipid-rich inflamed coronary plaques are prone to rupture. The purpose of this study was to assess lipid-rich inflamed plaques in vivo using fully integrated high-speed optical coherence tomography (OCT)/near-infrared fluorescence (NIRF) molecular imaging with a Food and Drug Administration-approved indocyanine green (ICG). An integrated high-speed intravascular OCT/NIRF imaging catheter and a dual-modal OCT/NIRF system were constructed based on a clinical OCT platform. For imaging lipid-rich inflamed plaques, the Food and Drug Administration-approved NIRF-emitting ICG (2.25 mg/kg) or saline was injected intravenously into rabbit models with experimental atheromata induced by balloon injury and 12- to 14-week high-cholesterol diets. Twenty minutes after injection, in vivo OCT/NIRF imaging of the infrarenal aorta and iliac arteries was acquired only under contrast flushing through catheter (pullback speed up to ≤20 mm/s). NIRF signals were strongly detected in the OCT-visualized atheromata of the ICG-injected rabbits. The in vivo NIRF target-to-background ratio was significantly larger in the ICG-injected rabbits than in the saline-injected controls (Pfluorescence reflectance imaging, which correlated well with the in vivo target-to-background ratios (Pfluorescence microscopy, and histopathology also corroborated the in vivo imaging findings. Integrated OCT/NIRF structural/molecular imaging with a Food and Drug Administration -approved ICG accurately identified lipid-rich inflamed atheromata in coronary-sized vessels. This highly translatable dual-modal imaging approach could enhance our capabilities to detect high-risk coronary plaques. © 2014 American Heart Association, Inc.

  19. Infrared tomography for diagnostic imaging of port wine stain blood vessels

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, D. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    The objective of this work is the development of Infrared Tomography (IRT) for detecting and characterizing subsurface chromophores in human skin. Characterization of cutaneous chromophores is crucial for advances in the laser treatment of pigmented lesions (e.g., port wine stain birthmarks and tatoos). Infrared tomography (IRT) uses a fast infrared focal plane array (IR-FPA) to detect temperature rises in a substrate induced by pulsed radiation. A pulsed laser is used to produce transient heating of an object. The temperature rise, due to the optical absorption of the pulsed laser light, creates an increase in infrared emission which is measured by the IR-FPA. Although the application of IRT to image subsurface cracks due to metal fatigue is a topic of great interest in the aircraft industry, the application to image subsurface chromophores in biological materials is novel. We present an image recovery method based on a constrained conjugate gradient algorithm that has obtained the first ever high quality images of port wine blood vessels.

  20. Whole-brain intracranial vessel wall imaging at 3 Tesla using cerebrospinal fluid-attenuated T1-weighted 3D turbo spin echo.

    Science.gov (United States)

    Fan, Zhaoyang; Yang, Qi; Deng, Zixin; Li, Yuxia; Bi, Xiaoming; Song, Shlee; Li, Debiao

    2017-03-01

    Although three-dimensional (3D) turbo spin echo (TSE) with variable flip angles has proven to be useful for intracranial vessel wall imaging, it is associated with inadequate suppression of cerebrospinal fluid (CSF) signals and limited spatial coverage at 3 Tesla (T). This work aimed to modify the sequence and develop a protocol to achieve whole-brain, CSF-attenuated T 1 -weighted vessel wall imaging. Nonselective excitation and a flip-down radiofrequency pulse module were incorporated into a commercial 3D TSE sequence. A protocol based on the sequence was designed to achieve T 1 -weighted vessel wall imaging with whole-brain spatial coverage, enhanced CSF-signal suppression, and isotropic 0.5-mm resolution. Human volunteer and pilot patient studies were performed to qualitatively and quantitatively demonstrate the advantages of the sequence. Compared with the original sequence, the modified sequence significantly improved the T 1 -weighted image contrast score (2.07 ± 0.19 versus 3.00 ± 0.00, P = 0.011), vessel wall-to-CSF contrast ratio (0.14 ± 0.16 versus 0.52 ± 0.30, P = 0.007) and contrast-to-noise ratio (1.69 ± 2.18 versus 4.26 ± 2.30, P = 0.022). Significant improvement in vessel wall outer boundary sharpness was observed in several major arterial segments. The new 3D TSE sequence allows for high-quality T 1 -weighted intracranial vessel wall imaging at 3 T. It may potentially aid in depicting small arteries and revealing T 1 -mediated high-signal wall abnormalities. Magn Reson Med 77:1142-1150, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  1. Cerebral Small Vessel Disease: Cognition, Mood, Daily Functioning, and Imaging Findings from a Small Pilot Sample

    Directory of Open Access Journals (Sweden)

    John G. Baker

    2012-04-01

    Full Text Available Cerebral small vessel disease, a leading cause of cognitive decline, is considered a relatively homogeneous disease process, and it can co-occur with Alzheimer’s disease. Clinical reports of magnetic resonance imaging (MRI/computed tomography and single photon emission computed tomography (SPECT imaging and neuropsychology testing for a small pilot sample of 14 patients are presented to illustrate disease characteristics through findings from structural and functional imaging and cognitive assessment. Participants showed some decreases in executive functioning, attention, processing speed, and memory retrieval, consistent with previous literature. An older subgroup showed lower age-corrected scores at a single time point compared to younger participants. Performance on a computer-administered cognitive measure showed a slight overall decline over a period of 8–28 months. For a case study with mild neuropsychology findings, the MRI report was normal while the SPECT report identified perfusion abnormalities. Future research can test whether advances in imaging analysis allow for identification of cerebral small vessel disease before changes are detected in cognition.

  2. Intracranial Vascular Disease Evaluation With Combined Vessel Wall Imaging And Patient Specific Hemodynamics

    Science.gov (United States)

    Samson, Kurt; Mossa-Basha, Mahmud; Yuan, Chun; Canton, Maria De Gador; Aliseda, Alberto

    2017-11-01

    Intracranial vascular pathologies are evaluated with angiography, conventional digital subtraction angiography or non-invasive (MRI, CT). Current techniques present limitations on the resolution with which the vessel wall characteristics can be measured, presenting a major challenge to differential diagnostic of cerebral vasculopathies. A new combined approach is presented that incorporates patient-specific image-based CFD models with intracranial vessel-wall MRI (VWMRI). Comparisons of the VWMRI measurements, evaluated for the presence of wall enhancement and thin-walled regions, against CFD metrics such as wall shear stress (WSS), and oscillatory shear index (OSI) are used to understand how the new imaging technique developed can predict the influence of hemodynamics on the deterioration of the aneurysmal wall, leading to rupture. Additionally, histology of each resected aneurysm, evaluated for inflammatory infiltration and wall thickness features, is used to validate the analysis from VWMRI and CFD. This data presents a solid foundation on which to build a new framework for combined VWMRI-CFD to predict unstable wall changes in unruptured intracranial aneurysms, and support clinical monitoring and intervention decisions.

  3. Tumor Blood Vessel Dynamics

    Science.gov (United States)

    Munn, Lance

    2009-11-01

    ``Normalization'' of tumor blood vessels has shown promise to improve the efficacy of chemotherapeutics. In theory, anti-angiogenic drugs targeting endothelial VEGF signaling can improve vessel network structure and function, enhancing the transport of subsequent cytotoxic drugs to cancer cells. In practice, the effects are unpredictable, with varying levels of success. The predominant effects of anti-VEGF therapies are decreased vessel leakiness (hydraulic conductivity), decreased vessel diameters and pruning of the immature vessel network. It is thought that each of these can influence perfusion of the vessel network, inducing flow in regions that were previously sluggish or stagnant. Unfortunately, when anti-VEGF therapies affect vessel structure and function, the changes are dynamic and overlapping in time, and it has been difficult to identify a consistent and predictable normalization ``window'' during which perfusion and subsequent drug delivery is optimal. This is largely due to the non-linearity in the system, and the inability to distinguish the effects of decreased vessel leakiness from those due to network structural changes in clinical trials or animal studies. We have developed a mathematical model to calculate blood flow in complex tumor networks imaged by two-photon microscopy. The model incorporates the necessary and sufficient components for addressing the problem of normalization of tumor vasculature: i) lattice-Boltzmann calculations of the full flow field within the vasculature and within the tissue, ii) diffusion and convection of soluble species such as oxygen or drugs within vessels and the tissue domain, iii) distinct and spatially-resolved vessel hydraulic conductivities and permeabilities for each species, iv) erythrocyte particles advecting in the flow and delivering oxygen with real oxygen release kinetics, v) shear stress-mediated vascular remodeling. This model, guided by multi-parameter intravital imaging of tumor vessel structure

  4. Elliptical Local Vessel Density: a Fast and Robust Quality Metric for Fundus Images

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Chaum, Edward [ORNL; Karnowski, Thomas Paul [ORNL; Meriaudeau, Fabrice [ORNL; Tobin Jr, Kenneth William [ORNL; Abramoff, M.D. [University of Iowa

    2008-01-01

    A great effort of the research community is geared towards the creation of an automatic screening system able to promptly detect diabetic retinopathy with the use of fundus cameras. In addition, there are some documented approaches to the problem of automatically judging the image quality. We propose a new set of features independent of Field of View or resolution to describe the morphology of the patient's vessels. Our initial results suggest that they can be used to estimate the image quality in a time one order of magnitude shorter respect to previous techniques.

  5. Lung vessel segmentation in CT images using graph-cuts

    Science.gov (United States)

    Zhai, Zhiwei; Staring, Marius; Stoel, Berend C.

    2016-03-01

    Accurate lung vessel segmentation is an important operation for lung CT analysis. Filters that are based on analyzing the eigenvalues of the Hessian matrix are popular for pulmonary vessel enhancement. However, due to their low response at vessel bifurcations and vessel boundaries, extracting lung vessels by thresholding the vesselness is not sufficiently accurate. Some methods turn to graph-cuts for more accurate segmentation, as it incorporates neighbourhood information. In this work, we propose a new graph-cuts cost function combining appearance and shape, where CT intensity represents appearance and vesselness from a Hessian-based filter represents shape. Due to the amount of voxels in high resolution CT scans, the memory requirement and time consumption for building a graph structure is very high. In order to make the graph representation computationally tractable, those voxels that are considered clearly background are removed from the graph nodes, using a threshold on the vesselness map. The graph structure is then established based on the remaining voxel nodes, source/sink nodes and the neighbourhood relationship of the remaining voxels. Vessels are segmented by minimizing the energy cost function with the graph-cuts optimization framework. We optimized the parameters used in the graph-cuts cost function and evaluated the proposed method with two manually labeled sub-volumes. For independent evaluation, we used 20 CT scans of the VESSEL12 challenge. The evaluation results of the sub-volume data show that the proposed method produced a more accurate vessel segmentation compared to the previous methods, with F1 score 0.76 and 0.69. In the VESSEL12 data-set, our method obtained a competitive performance with an area under the ROC curve of 0.975, especially among the binary submissions.

  6. Imaging of large vessel vasculitis with 18FDG PET: illusion or reality? A critical review of the literature data

    International Nuclear Information System (INIS)

    Belhocine, Tarik; Vandevivere, Johan; Blockmans, Daniel; Hustinx, Roland; Mortelmans, Luc

    2003-01-01

    Fluorine-18 fluorodeoxyglucose positron emission tomography ( 18 FDG PET) plays a major role in the management of oncology patients. Owing to the singular properties of the glucose tracer, many patients suffering from non-malignant diseases such as inflammatory or infectious diseases may also derive clinical benefit from the appropriate use of metabolic imaging. Large vessel vasculitides such as giant cell arteritis and Takayasu arteritis are other examples that may potentially extend the field of 18 FDG PET indications. The purpose of the present article is to assess the feasibility of metabolic imaging in vasculitis on the basis of the current literature data. In particular, the clinical context and the 18 FDG imaging patterns seen in patients with large vessel vasculitis are analysed in order to identify potential indications for metabolic imaging. (orig.)

  7. Investigation of vessel visibility of iterative reconstruction method in coronary computed tomography angiography using simulated vessel phantom

    International Nuclear Information System (INIS)

    Inoue, Takeshi; Uto, Fumiaki; Ichikawa, Katsuhiro; Hara, Takanori; Urikura, Atsushi; Hoshino, Takashi; Miura, Youhei; Terakawa, Syouichi

    2012-01-01

    Iterative reconstruction methods can reduce the noise of computed tomography (CT) images, which are expected to contribute to the reduction of patient dose CT examinations. The purpose of this study was to investigate impact of an iterative reconstruction method (iDose 4 , Philips Healthcare) on vessel visibility in coronary CT angiography (CTA) by using phantom studies. A simulated phantom was scanned by a CT system (iCT, Philips Healthcare), and the axial images were reconstructed by filtered back projection (FBP) and given a level of 1 to 7 (L1-L7) of the iterative reconstruction (IR). The vessel visibility was evaluated by a quantitative analysis using profiles across a 1.5-mm diameter simulated vessel as well as visual evaluation for multi planar reformation (MPR) images and volume rendering (VR) images in terms of the normalized-rank method with analysis of variance. The peak CT value of the profiles decreased with IR level and full width at half maximum of the profile also decreased with the IR level. For normalized-rank method, there was no statistical difference between FBP and L1 (20% dose reduction) for both MPR and VR images. The IR levels higher than L1 sacrificed the spatial resolution for the 1.5-mm simulated vessel, and their visual vessel visibilities were significantly inferior to that of the FBP. (author)

  8. The diagnostic value of cine-MR imaging in diseases of great vessels

    International Nuclear Information System (INIS)

    Sasaki, Shigeyuki; Yoshida, Hideaki; Matsui, Yoshiro; Sakuma, Makoto; Yasuda, Keihide; Tanabe, Tatsuzo; Chouji, H.

    1990-01-01

    The diagnostic value of cine magnetic resonance imaging (cine-MRI) was evaluated in 10 patients with diseases of great vessels. The parameters necessary to decide the appropriate treatment, such as presence and extension of intimal flap, DeBakey type classification, identification of the entry, differentiation between true and false lumen, and between thrombosis and slow flow were demonstrated in all patients with dissecting aortic aneurysm. However, abdominal aortic branches could not be demonstrated enough by cine-MRI, therefore conventional AOG was necessary to choose the operative procedure in these cases. In patients with thoracic aortic aneurysm (TAA), cine-MRI was valuable in demonstrating both blood flow and thrombus in the lumen of aneurysm, and AOG was thought to be unnecessary in most cases. Cine-MRI is a promising new technique for the evaluation of diseases of great vessels. (author)

  9. Freezing resistance in Patagonian woody shrubs: the role of cell wall elasticity and stem vessel size.

    Science.gov (United States)

    Zhang, Yong-Jiang; Bucci, Sandra J; Arias, Nadia S; Scholz, Fabian G; Hao, Guang-You; Cao, Kun-Fang; Goldstein, Guillermo

    2016-08-01

    Freezing resistance through avoidance or tolerance of extracellular ice nucleation is important for plant survival in habitats with frequent subzero temperatures. However, the role of cell walls in leaf freezing resistance and the coordination between leaf and stem physiological processes under subzero temperatures are not well understood. We studied leaf and stem responses to freezing temperatures, leaf and stem supercooling, leaf bulk elastic modulus and stem xylem vessel size of six Patagonian shrub species from two sites (plateau and low elevation sites) with different elevation and minimum temperatures. Ice seeding was initiated in the stem and quickly spread to leaves, but two species from the plateau site had barriers against rapid spread of ice. Shrubs with xylem vessels smaller in diameter had greater stem supercooling capacity, i.e., ice nucleated at lower subzero temperatures. Only one species with the lowest ice nucleation temperature among all species studied exhibited freezing avoidance by substantial supercooling, while the rest were able to tolerate extracellular freezing from -11.3 to -20 °C. Leaves of species with more rigid cell walls (higher bulk elastic modulus) could survive freezing to lower subzero temperatures, suggesting that rigid cell walls potentially reduce the degree of physical injury to cell membranes during the extracellular freezing and/or thaw processes. In conclusion, our results reveal the temporal-spatial ice spreading pattern (from stem to leaves) in Patagonian shrubs, and indicate the role of xylem vessel size in determining supercooling capacity and the role of cell wall elasticity in determining leaf tolerance of extracellular ice formation. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Photoacoustic imaging of blood vessels with a double-ring sensor featuring a narrow angular aperture

    NARCIS (Netherlands)

    Kolkman, R.G.M.; Hondebrink, Erwin; Steenbergen, Wiendelt; van Leeuwen, Ton; de Mul, F.F.M.

    2004-01-01

    A photoacoustic double-ring sensor, featuring a narrow angular aperture, is developed for laser-induced photoacoustic imaging of blood vessels. An integrated optical fiber enables reflection-mode detection of ultrasonic waves. By using the cross-correlation between the signals detected by the two

  11. JPEG and wavelet compression of ophthalmic images

    Science.gov (United States)

    Eikelboom, Robert H.; Yogesan, Kanagasingam; Constable, Ian J.; Barry, Christopher J.

    1999-05-01

    This study was designed to determine the degree and methods of digital image compression to produce ophthalmic imags of sufficient quality for transmission and diagnosis. The photographs of 15 subjects, which inclined eyes with normal, subtle and distinct pathologies, were digitized to produce 1.54MB images and compressed to five different methods: (i) objectively by calculating the RMS error between the uncompressed and compressed images, (ii) semi-subjectively by assessing the visibility of blood vessels, and (iii) subjectively by asking a number of experienced observers to assess the images for quality and clinical interpretation. Results showed that as a function of compressed image size, wavelet compressed images produced less RMS error than JPEG compressed images. Blood vessel branching could be observed to a greater extent after Wavelet compression compared to JPEG compression produced better images then a JPEG compression for a given image size. Overall, it was shown that images had to be compressed to below 2.5 percent for JPEG and 1.7 percent for Wavelet compression before fine detail was lost, or when image quality was too poor to make a reliable diagnosis.

  12. The value of ultrasonographic examination in the evaluation of liver size and intrahepatic vessels; Wartosc badania ultrasonograficznego w ocenie wielkosci watroby i naczyn wewnatrzwatrobowych u psa i kotow

    Energy Technology Data Exchange (ETDEWEB)

    Narojek, T. [Szkola Glowna Gospodarstwa Wiejskiego, Warsaw (Poland)

    1995-12-31

    The objective of the investigations was to comparatively evaluate the size and shape of the liver on the basis of x-ray and ultrasonographic examinations and to estimate the liver parenchyma and intrahepatic vessels on the basis of ultrasonographic examinations. The studies were done on 64 dogs and 13 cats of different breed and sex, aged from 1 day to 18 years. The ultrasonographic examinations were done with the use of Bruel and Kjaer apparatus type 1849 and Concept 2000 by Dynamic Imaging. In 64 animals the ultrasonographic image of the liver was normal. In 7 cases an enlargement of the liver without any changes in the liver parenchyma was noted. An enlargement of intrahepatic veins was found in 8 cases (4 with circulatory insufficiency, 2 with ascites). The assessment of the size and shape of the liver done on that basis of ultrasound examinations agreed with that based on x-ray examinations. The ultrasonic examinations also allowed the evaluation of the liver parenchyma and intrahepatic veins. (author). 9 refs, figs, 3 tabs.

  13. Detection of compression vessels in trigeminal neuralgia by surface-rendering three-dimensional reconstruction of 1.5- and 3.0-T magnetic resonance imaging.

    Science.gov (United States)

    Shimizu, Masahiro; Imai, Hideaki; Kagoshima, Kaiei; Umezawa, Eriko; Shimizu, Tsuneo; Yoshimoto, Yuhei

    2013-01-01

    Surface-rendered three-dimensional (3D) 1.5-T magnetic resonance (MR) imaging is useful for presurgical simulation of microvascular decompression. This study compared the sensitivity and specificity of 1.5- and 3.0-T surface-rendered 3D MR imaging for preoperative identification of the compression vessels of trigeminal neuralgia. One hundred consecutive patients underwent microvascular decompression for trigeminal neuralgia. Forty and 60 patients were evaluated by 1.5- and 3.0-T MR imaging, respectively. Three-dimensional MR images were constructed on the basis of MR imaging, angiography, and venography data and evaluated to determine the compression vessel before surgery. MR imaging findings were compared with the microsurgical findings to compare the sensitivity and specificity of 1.5- and 3.0-T MR imaging. The agreement between MR imaging and surgical findings depended on the compression vessels. For superior cerebellar artery, 1.5- and 3.0-T MR imaging had 84.4% and 82.7% sensitivity and 100% and 100% specificity, respectively. For anterior inferior cerebellar artery, 1.5- and 3.0-T MR imaging had 33.3% and 50% sensitivity and 92.9% and 95% specificity, respectively. For the petrosal vein, 1.5- and 3.0-T MR imaging had 75% and 64.3% sensitivity and 79.2% and 78.1% specificity, respectively. Complete pain relief was obtained in 36 of 40 and 55 of 60 patients undergoing 1.5- and 3.0-T MR imaging, respectively. The present study showed that both 1.5- and 3.0-T MR imaging provided high sensitivity and specificity for preoperative assessment of the compression vessels of trigeminal neuralgia. Preoperative 3D imaging provided very high quality presurgical simulation, resulting in excellent clinical outcomes. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Value of CT angiography in anterior circulation large vessel occlusive stroke: Imaging findings, pearls, and pitfalls

    Energy Technology Data Exchange (ETDEWEB)

    Power, Sarah, E-mail: drsarahpower@gmail.com [Department of Neuroradiology, Beaumont Hospital, P.O. Box 1297, Beaumont Rd, Dublin 9 (Ireland); McEvoy, Sinead H., E-mail: sineadmcevoy@beaumont.ie [Department of Neuroradiology, Beaumont Hospital, P.O. Box 1297, Beaumont Rd, Dublin 9 (Ireland); Cunningham, Jane, E-mail: janecunningham0708@gmail.com [Department of Radiology, Beaumont Hospital, P.O. Box 1297, Beaumont Rd, Dublin 9 (Ireland); Ti, Joanna P., E-mail: joannapearlyti@gmail.com [Department of Neuroradiology, Beaumont Hospital, P.O. Box 1297, Beaumont Rd, Dublin 9 (Ireland); Looby, Seamus, E-mail: seamuslooby@beaumont.ie [Department of Neuroradiology, Beaumont Hospital, P.O. Box 1297, Beaumont Rd, Dublin 9 (Ireland); O' Hare, Alan, E-mail: alanohare@beaumont.ie [Department of Neuroradiology, Beaumont Hospital, P.O. Box 1297, Beaumont Rd, Dublin 9 (Ireland); Williams, David, E-mail: davidwilliams@rcsi.ie [Department of Geriatrics and Stroke Medicine, Royal College of Surgeons in Ireland (RCSI) and Beaumont Hospital, P.O. Box 1297, Beaumont Rd, Dublin 9 (Ireland); Brennan, Paul, E-mail: paulbrennan@beaumont.ie [Department of Neuroradiology, Beaumont Hospital, P.O. Box 1297, Beaumont Rd, Dublin 9 (Ireland); Thornton, John, E-mail: johnthornton@beaumont.ie [Department of Neuroradiology, Beaumont Hospital, P.O. Box 1297, Beaumont Rd, Dublin 9 (Ireland)

    2015-07-15

    Highlights: • Site of occlusion determines potential collateralization routes and impacts outcome. • Multifocality of arterial occlusion is common, seen in approximately 20% of cases. • ICA false occlusion sign can be seen in setting of ICA stenosis or carotid T occlusion. • False patency sign: hyperdense thrombus/calcified occlusive plaque misinterpreted as patent vessel. • Additional abnormalities on CTA may infer stroke mechanism or alter decision making. - Abstract: Hyperacute stroke imaging is playing an increasingly important role in determining management decisions in acute stroke patients, particularly patients with large vessel occlusive stroke who may benefit from endovascular intervention. CT angiography (CTA) is an important tool in the work-up of the acute stroke patient. It reliably detects large occlusive thrombi in proximal cerebral arteries and is a quick and highly accurate method in identifying candidates for endovascular stroke treatment. In this article we review the imaging findings on CTA in acute large vessel occlusive stroke using a pictorial case based approach. We retrospectively reviewed CTA studies in 48 patients presenting with acute anterior circulation large vessel occlusive stroke who were brought for intra-arterial acute stroke intervention. We discuss and illustrate patterns of proximal intracranial arterial occlusion, collateralization to the occluded territory, as well as reviewing some important pearls, pitfalls and teaching points in CTA assessment of the acute stroke patient. Performed from the level of the aortic arch CTA also gives valuable information regarding the state of other vessels in the acute stroke patient, identifying additional significant vascular stenoses or occlusions, and as we illustrate, can demonstrate other clinically significant findings which may impact on patient management and outcome.

  15. Value of CT angiography in anterior circulation large vessel occlusive stroke: Imaging findings, pearls, and pitfalls

    International Nuclear Information System (INIS)

    Power, Sarah; McEvoy, Sinead H.; Cunningham, Jane; Ti, Joanna P.; Looby, Seamus; O'Hare, Alan; Williams, David; Brennan, Paul; Thornton, John

    2015-01-01

    Highlights: • Site of occlusion determines potential collateralization routes and impacts outcome. • Multifocality of arterial occlusion is common, seen in approximately 20% of cases. • ICA false occlusion sign can be seen in setting of ICA stenosis or carotid T occlusion. • False patency sign: hyperdense thrombus/calcified occlusive plaque misinterpreted as patent vessel. • Additional abnormalities on CTA may infer stroke mechanism or alter decision making. - Abstract: Hyperacute stroke imaging is playing an increasingly important role in determining management decisions in acute stroke patients, particularly patients with large vessel occlusive stroke who may benefit from endovascular intervention. CT angiography (CTA) is an important tool in the work-up of the acute stroke patient. It reliably detects large occlusive thrombi in proximal cerebral arteries and is a quick and highly accurate method in identifying candidates for endovascular stroke treatment. In this article we review the imaging findings on CTA in acute large vessel occlusive stroke using a pictorial case based approach. We retrospectively reviewed CTA studies in 48 patients presenting with acute anterior circulation large vessel occlusive stroke who were brought for intra-arterial acute stroke intervention. We discuss and illustrate patterns of proximal intracranial arterial occlusion, collateralization to the occluded territory, as well as reviewing some important pearls, pitfalls and teaching points in CTA assessment of the acute stroke patient. Performed from the level of the aortic arch CTA also gives valuable information regarding the state of other vessels in the acute stroke patient, identifying additional significant vascular stenoses or occlusions, and as we illustrate, can demonstrate other clinically significant findings which may impact on patient management and outcome

  16. Imaging features of primary Sarcomas of the great vessels in CT, MRI and PET/CT: a single-center experience

    International Nuclear Information System (INIS)

    Falck, Christian von; Meyer, Bernhard; Fegbeutel, Christine; Länger, Florian; Bengel, Frank; Wacker, Frank; Rodt, Thomas

    2013-01-01

    To investigate the imaging features of primary sarcomas of the great vessels in CT, MRI and 18 F-FDG PET/CT. Thirteen patients with a primary sarcoma of the great vessels were retrospectively evaluated. All available images studies including F-18 FDG PET(/CT) (n = 4), MDCT (n = 12) and MRI (n = 6) were evaluated and indicative image features of this rare tumor entity were identified. The median interval between the first imaging study and the final diagnosis was 11 weeks (0–12 weeks). The most frequently observed imaging findings suggestive of malignant disease in patients with sarcomas of the pulmonary arteries were a large filling defect with vascular distension, unilaterality and a lack of improvement despite effective anticoagulation. In patients with aortic sarcomas we most frequently observed a pedunculated appearance and an atypical location of the filling defect. The F-18 FDG PET(/CT) examinations demonstrated an unequivocal hypermetabolism of the lesion in all cases (4/4). MRI proved lesion vascularization in 5/6 cases. Intravascular unilateral or atypically located filling defects of the great vessels with vascular distension, a pedunculated shape and lack of improvement despite effective anticoagulation are suspicious for primary sarcoma on MDCT or MRI. MR perfusion techniques can add information on the nature of the lesion but the findings may be subtle and equivocal. F-18 FDG PET/CT may have a potential role in these patients and may be considered as part of the imaging workup

  17. In vivo imaging of stepwise vessel occlusion in cerebral photothrombosis of mice by 19F MRI.

    Directory of Open Access Journals (Sweden)

    Gesa Weise

    Full Text Available (19F magnetic resonance imaging (MRI was recently introduced as a promising technique for in vivo cell tracking. In the present study we compared (19F MRI with iron-enhanced MRI in mice with photothrombosis (PT at 7 Tesla. PT represents a model of focal cerebral ischemia exhibiting acute vessel occlusion and delayed neuroinflammation.Perfluorocarbons (PFC or superparamagnetic iron oxide particles (SPIO were injected intravenously at different time points after photothrombotic infarction. While administration of PFC directly after PT induction led to a strong (19F signal throughout the entire lesion, two hours delayed application resulted in a rim-like (19F signal at the outer edge of the lesion. These findings closely resembled the distribution of signal loss on T2-weighted MRI seen after SPIO injection reflecting intravascular accumulation of iron particles trapped in vessel thrombi as confirmed histologically. By sequential administration of two chemically shifted PFC compounds 0 and 2 hours after illumination the different spatial distribution of the (19F markers (infarct core/rim could be visualized in the same animal. When PFC were applied at day 6 the fluorine marker was only detected after long acquisition times ex vivo. SPIO-enhanced MRI showed slight signal loss in vivo which was much more prominent ex vivo indicative for neuroinflammation at this late lesion stage.Our study shows that vessel occlusion can be followed in vivo by (19F and SPIO-enhanced high-field MRI while in vivo imaging of neuroinflammation remains challenging. The timing of contrast agent application was the major determinant of the underlying processes depicted by both imaging techniques. Importantly, sequential application of different PFC compounds allowed depiction of ongoing vessel occlusion from the core to the margin of the ischemic lesions in a single MRI measurement.

  18. Non-invasive assessment of vessel morphology and function in tumors by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Kiessling, Fabian; Jugold, Manfred; Woenne, Eva C.; Brix, Gunnar

    2007-01-01

    The switch to an angiogenic phenotype is an important precondition for tumor growth, invasion and spread. Since newly formed vessels are characterized by structural, functional and molecular abnormalities, they offer promising targets for tumor diagnosis and therapy. Previous studies indicate that MRI is valuable to assess vessel morphology and function. It can be used to distinguish between benign and malignant lesions and to improve delineation of proliferating areas within heterogeneous tumors. In addition, tracer kinetic analysis of contrast-enhanced image series allows the estimation of well-defined physiological parameters such as blood volume, blood flow and vessel permeability. Frequently, changes of these parameters during cytostatic, anti-angiogenic and radiation therapy precede tumor volume reduction. Moreover, target-specific MRI techniques can be used to elucidate the expression of angiogenic markers at the molecular level. This review summarizes strategies for non-invasive characterization of tumor vascularization by functional and molecular MRI, hereby introducing representative preclinical and clinical applications. (orig.)

  19. CT angiography of intracranial arterial vessels: impact of tube voltage and contrast media concentration on image quality

    International Nuclear Information System (INIS)

    Ramgren, Birgitta; Holtaas, Stig; Siemund, Roger; Dept. of Radiology, Lund Univ., Lund

    2012-01-01

    Background Computed tomography angiography (CTA) of intracranial arteries has high demands on image quality. Important parameters influencing vessel enhancement are injection rate, concentration of contrast media and tube voltage. Purpose To evaluate the impact of an increase of contrast media concentration from 300 to 400 mg iodine/mL (mgI/mL) and the effect of a decrease of tube voltage from 120 to 90 kVp on vessel attenuation and image quality in CT angiography of intracranial arteries. Material and Methods Sixty-three patients were included into three protocol groups: Group I, 300 mgI/mL 120 kVp; Group II, 400 mgI/mL 120 kVp; Group III, 400 mgI/mL 90 kVp. Hounsfield units (HU) were measured in the internal carotid artery (ICA) and the M1 and M2 segments of the middle cerebral artery. Image quality grading was performed regarding M1 and M2 segments, volume rendering and general image impression. Results The difference in mean HU in ICA concerning the effect of contrast media concentration was statistically significant (P = 0.03) in favor of higher concentration. The difference in ICA enhancement due to the effect of tube voltage was statistically significant (P < 0.01) in favor of lower tube voltage. The increase of contrast medium concentration raised the mean enhancement in ICA with 18% and the decrease of tube voltage raised the mean enhancement with 37%. Image quality grading showed a trend towards improved grading for higher contrast concentration and lower tube voltage. Statistically significant better grading was found for the combined effect of both measures except for general impression (P 0.01-0.05). Conclusion The uses of highly concentrated contrast media and low tube voltage are easily performed measures to improve image quality in CTA of intracranial vessel

  20. Automatic detection and segmentation of vascular structures in dermoscopy images using a novel vesselness measure based on pixel redness and tubularness

    Science.gov (United States)

    Kharazmi, Pegah; Lui, Harvey; Stoecker, William V.; Lee, Tim

    2015-03-01

    Vascular structures are one of the most important features in the diagnosis and assessment of skin disorders. The presence and clinical appearance of vascular structures in skin lesions is a discriminating factor among different skin diseases. In this paper, we address the problem of segmentation of vascular patterns in dermoscopy images. Our proposed method is composed of three parts. First, based on biological properties of human skin, we decompose the skin to melanin and hemoglobin component using independent component analysis of skin color images. The relative quantities and pure color densities of each component were then estimated. Subsequently, we obtain three reference vectors of the mean RGB values for normal skin, pigmented skin and blood vessels from the hemoglobin component by averaging over 100000 pixels of each group outlined by an expert. Based on the Euclidean distance thresholding, we generate a mask image that extracts the red regions of the skin. Finally, Frangi measure was applied to the extracted red areas to segment the tubular structures. Finally, Otsu's thresholding was applied to segment the vascular structures and get a binary vessel mask image. The algorithm was implemented on a set of 50 dermoscopy images. In order to evaluate the performance of our method, we have artificially extended some of the existing vessels in our dermoscopy data set and evaluated the performance of the algorithm to segment the newly added vessel pixels. A sensitivity of 95% and specificity of 87% were achieved.

  1. Retinal Vessels Segmentation Techniques and Algorithms: A Survey

    Directory of Open Access Journals (Sweden)

    Jasem Almotiri

    2018-01-01

    Full Text Available Retinal vessels identification and localization aim to separate the different retinal vasculature structure tissues, either wide or narrow ones, from the fundus image background and other retinal anatomical structures such as optic disc, macula, and abnormal lesions. Retinal vessels identification studies are attracting more and more attention in recent years due to non-invasive fundus imaging and the crucial information contained in vasculature structure which is helpful for the detection and diagnosis of a variety of retinal pathologies included but not limited to: Diabetic Retinopathy (DR, glaucoma, hypertension, and Age-related Macular Degeneration (AMD. With the development of almost two decades, the innovative approaches applying computer-aided techniques for segmenting retinal vessels are becoming more and more crucial and coming closer to routine clinical applications. The purpose of this paper is to provide a comprehensive overview for retinal vessels segmentation techniques. Firstly, a brief introduction to retinal fundus photography and imaging modalities of retinal images is given. Then, the preprocessing operations and the state of the art methods of retinal vessels identification are introduced. Moreover, the evaluation and validation of the results of retinal vessels segmentation are discussed. Finally, an objective assessment is presented and future developments and trends are addressed for retinal vessels identification techniques.

  2. 3D reconstruction of microvascular flow phantoms with hybrid imaging modalities

    Science.gov (United States)

    Lin, Jingying; Hsiung, Kevin; Ritenour, Russell; Golzarian, Jafar

    2011-03-01

    Microvascular flow phantoms were built to aid the development of a hemodynamic simulation model for treating hepatocelluar carcinoma. The goal is to predict the blood flow routing for embolotherapy planning. Embolization is to deliver agents (e.g. microspheres) to the vicinity of the tumor to obstruct blood supply and nutrients to the tumor, targeting into 30 - 40 μm arterioles. Due to the size of the catheter, it has to release microspheres at an upper stream location, which may not localize the blocking effect. Accurate anatomical descriptions of microvasculature will help to conduct a reliable simulation and prepare a successful embolization strategy. Modern imaging devices can generate 3D reconstructions with ease. However, with a fixed detector size, larger field of view yields lower resolution. Clinical CT images can't be used to measure micro vessel dimensions, while micro-CT requires more acquisitions to reconstruct larger vessels. A multi-tiered, montage 3D reconstruction method with hybrid-modality imagery is devised to minimize the reconstruction effort. Regular CT is used for larger vessels and micro-CT is used for micro vessels. The montage approach aims to stitch up images with different resolutions and orientations. A resolution-adaptable 3D image registration is developed to assemble the images. We have created vessel phantoms that consist of several tiers of bifurcating polymer tubes in reducing diameters, down to 25 μm. No previous work of physical flow phantom has ventured into this small scale. Overlapping phantom images acquired from clinical CT and micro-CT are used to verify the image registration fidelity.

  3. Computed tomography depiction of small pediatric vessels with model-based iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Koc, Gonca; Courtier, Jesse L.; Phelps, Andrew; Marcovici, Peter A.; MacKenzie, John D. [UCSF Benioff Children' s Hospital, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States)

    2014-07-15

    Computed tomography (CT) is extremely important in characterizing blood vessel anatomy and vascular lesions in children. Recent advances in CT reconstruction technology hold promise for improved image quality and also reductions in radiation dose. This report evaluates potential improvements in image quality for the depiction of small pediatric vessels with model-based iterative reconstruction (Veo trademark), a technique developed to improve image quality and reduce noise. To evaluate Veo trademark as an improved method when compared to adaptive statistical iterative reconstruction (ASIR trademark) for the depiction of small vessels on pediatric CT. Seventeen patients (mean age: 3.4 years, range: 2 days to 10.0 years; 6 girls, 11 boys) underwent contrast-enhanced CT examinations of the chest and abdomen in this HIPAA compliant and institutional review board approved study. Raw data were reconstructed into separate image datasets using Veo trademark and ASIR trademark algorithms (GE Medical Systems, Milwaukee, WI). Four blinded radiologists subjectively evaluated image quality. The pulmonary, hepatic, splenic and renal arteries were evaluated for the length and number of branches depicted. Datasets were compared with parametric and non-parametric statistical tests. Readers stated a preference for Veo trademark over ASIR trademark images when subjectively evaluating image quality criteria for vessel definition, image noise and resolution of small anatomical structures. The mean image noise in the aorta and fat was significantly less for Veo trademark vs. ASIR trademark reconstructed images. Quantitative measurements of mean vessel lengths and number of branches vessels delineated were significantly different for Veo trademark and ASIR trademark images. Veo trademark consistently showed more of the vessel anatomy: longer vessel length and more branching vessels. When compared to the more established adaptive statistical iterative reconstruction algorithm, model

  4. Computed tomography depiction of small pediatric vessels with model-based iterative reconstruction

    International Nuclear Information System (INIS)

    Koc, Gonca; Courtier, Jesse L.; Phelps, Andrew; Marcovici, Peter A.; MacKenzie, John D.

    2014-01-01

    Computed tomography (CT) is extremely important in characterizing blood vessel anatomy and vascular lesions in children. Recent advances in CT reconstruction technology hold promise for improved image quality and also reductions in radiation dose. This report evaluates potential improvements in image quality for the depiction of small pediatric vessels with model-based iterative reconstruction (Veo trademark), a technique developed to improve image quality and reduce noise. To evaluate Veo trademark as an improved method when compared to adaptive statistical iterative reconstruction (ASIR trademark) for the depiction of small vessels on pediatric CT. Seventeen patients (mean age: 3.4 years, range: 2 days to 10.0 years; 6 girls, 11 boys) underwent contrast-enhanced CT examinations of the chest and abdomen in this HIPAA compliant and institutional review board approved study. Raw data were reconstructed into separate image datasets using Veo trademark and ASIR trademark algorithms (GE Medical Systems, Milwaukee, WI). Four blinded radiologists subjectively evaluated image quality. The pulmonary, hepatic, splenic and renal arteries were evaluated for the length and number of branches depicted. Datasets were compared with parametric and non-parametric statistical tests. Readers stated a preference for Veo trademark over ASIR trademark images when subjectively evaluating image quality criteria for vessel definition, image noise and resolution of small anatomical structures. The mean image noise in the aorta and fat was significantly less for Veo trademark vs. ASIR trademark reconstructed images. Quantitative measurements of mean vessel lengths and number of branches vessels delineated were significantly different for Veo trademark and ASIR trademark images. Veo trademark consistently showed more of the vessel anatomy: longer vessel length and more branching vessels. When compared to the more established adaptive statistical iterative reconstruction algorithm, model

  5. The probable types, sizes, positions and orientations of the defects which may appear in connection with manufacture of reactor vessels

    International Nuclear Information System (INIS)

    Bergh, S.

    1980-02-01

    An review of welding technology in manufacture of reactor vessels is made. An inventory of principal defects appearing in connection with manual ARC-welding and coated electrodes is presented. Some important welded joints of BWR reactor vessels are scrutinized. Reheating cracks may appear during stress relief annealing beneath the cladding, and this problem is discussed in the third part. The interest is focussed towards the defects which depend on the conditions during the welding. Slag and incomplete fusion might be found. The review can serve for the guidance of nondestructive testing. The defects are estimated to have the size of a few MM with a maximum to approx. 10 MM right across the weld, possibly with exception for the electroslag welds of the OKG-1 reactor vessel. (GBn)

  6. FFTF and CRBRP reactor vessels

    International Nuclear Information System (INIS)

    Morgan, R.E.

    1977-01-01

    The Fast Flux Test Facility (FFTF) reactor vessel and the Clinch River Breeder Reactor Plant (CRBRP) reactor vessel each serve to enclose a fast spectrum reactor core, contain the sodium coolant, and provide support and positioning for the closure head and internal structure. Each vessel is located in its reactor cavity and is protected by a guard vessel which would ensure continued decay heat removal capability should a major system leak develop. Although the two plants have significantly different thermal power ratings, 400 megawatts for FFTF and 975 megawatts for CRBRP, the two reactor vessels are comparable in size, the CRBRP vessel being approximately 28% longer than the FFTF vessel. The FFTF vessel diameter was controlled by the space required for the three individual In-Vessel Handling Machines and Instrument Trees. Utilization of the triple rotating plug scheme for CRBRP refueling enables packaging of the larger CRBRP core in a vessel the same diameter as the FFTF vessel

  7. Imaging of large vessel vasculitis with {sup 18}FDG PET: illusion or reality? A critical review of the literature data

    Energy Technology Data Exchange (ETDEWEB)

    Belhocine, Tarik; Vandevivere, Johan [Department of Nuclear Medicine, A.Z. Middelheim Hospital, 2020, Antwerp (Belgium); Blockmans, Daniel [Department of Internal Medicine, Gasthuisberg University Hospital, Leuven (Belgium); Hustinx, Roland [Department of Nuclear Medicine, University Hospital of Liege, Liege (Belgium); Mortelmans, Luc [Department of Nuclear Medicine, Gasthuisberg University Hospital, Leuven (Belgium)

    2003-09-01

    Fluorine-18 fluorodeoxyglucose positron emission tomography ({sup 18}FDG PET) plays a major role in the management of oncology patients. Owing to the singular properties of the glucose tracer, many patients suffering from non-malignant diseases such as inflammatory or infectious diseases may also derive clinical benefit from the appropriate use of metabolic imaging. Large vessel vasculitides such as giant cell arteritis and Takayasu arteritis are other examples that may potentially extend the field of {sup 18}FDG PET indications. The purpose of the present article is to assess the feasibility of metabolic imaging in vasculitis on the basis of the current literature data. In particular, the clinical context and the {sup 18}FDG imaging patterns seen in patients with large vessel vasculitis are analysed in order to identify potential indications for metabolic imaging. (orig.)

  8. Detection of vessel wall calcifications in vertebral arteries using susceptibility weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Lisa C.; Boeker, Sarah M.; Bender, Yvonne Y.; Fallenberg, Eva M.; Wagner, Moritz; Hamm, Bernd; Makowski, Marcus R. [Department of Radiology, Charite, Berlin (Germany); Liebig, Thomas [Department of Neuroradiology, Charite, Berlin (Germany)

    2017-09-15

    Calcification of the brain supplying arteries has been linked to an increased risk for cerebrovascular disease. The purpose of this study was to test the potential of susceptibility weighted MR imaging (SWMR) for the detection of vertebral artery calcifications, based on CT as a reference standard. Four hundred seventy-four patients, who had received head CT and 1.5 T MR scans with SWMR, including the distal vertebral artery, between January 2014 and December 2016, were retrospectively evaluated and 389 patients were included. Sensitivity and specificity for the detection of focal calcifications and intra- and interobserver agreement were calculated for SWMR and standard MRI, using CT as a standard of reference. The diameter of vertebral artery calcifications was used to assess correlations between imaging modalities. Furthermore, the degree of vessel stenosis was determined in 30 patients, who had received an additional angiography. On CT scans, 40 patients showed a total of 52 vertebral artery calcifications. While SWMR reached a sensitivity of 94% (95% CI 84-99%) and a specificity of 97% (95% CI 94-98%), standard MRI yielded a sensitivity of 33% (95% CI 20-46%), and a specificity of 93% (95% CI 90-96%). Linear regression analysis of size measurements confirmed a close correlation between SWMR and CT measurements (R {sup 2} = 0.74, p < 0.001). Compared to standard MRI (ICC = 0.52; CI 0.45-0.59), SWMR showed a higher interobserver agreement for calcification measurements (ICC = 0.84; CI 0.81-0.87). For detection of distal vertebral artery calcifications, SWMR demonstrates a performance comparable to CT and considerably higher than conventional MRI. (orig.)

  9. Segmentation of vessels cluttered with cells using a physics based model.

    Science.gov (United States)

    Schmugge, Stephen J; Keller, Steve; Nguyen, Nhat; Souvenir, Richard; Huynh, Toan; Clemens, Mark; Shin, Min C

    2008-01-01

    Segmentation of vessels in biomedical images is important as it can provide insight into analysis of vascular morphology, topology and is required for kinetic analysis of flow velocity and vessel permeability. Intravital microscopy is a powerful tool as it enables in vivo imaging of both vasculature and circulating cells. However, the analysis of vasculature in those images is difficult due to the presence of cells and their image gradient. In this paper, we provide a novel method of segmenting vessels with a high level of cell related clutter. A set of virtual point pairs ("vessel probes") are moved reacting to forces including Vessel Vector Flow (VVF) and Vessel Boundary Vector Flow (VBVF) forces. Incorporating the cell detection, the VVF force attracts the probes toward the vessel, while the VBVF force attracts the virtual points of the probes to localize the vessel boundary without being distracted by the image features of the cells. The vessel probes are moved according to Newtonian Physics reacting to the net of forces applied on them. We demonstrate the results on a set of five real in vivo images of liver vasculature cluttered by white blood cells. When compared against the ground truth prepared by the technician, the Root Mean Squared Error (RMSE) of segmentation with VVF and VBVF was 55% lower than the method without VVF and VBVF.

  10. Improved vessel morphology measurements in contrast-enhanced multi-detector computed tomography coronary angiography with non-linear post-processing

    International Nuclear Information System (INIS)

    Ferencik, Maros; Lisauskas, Jennifer B.; Cury, Ricardo C.; Hoffmann, Udo; Abbara, Suhny; Achenbach, Stephan; Karl, W. Clem; Brady, Thomas J.; Chan, Raymond C.

    2006-01-01

    Multi-detector computed tomography (MDCT) permits detection of coronary plaque. However, noise and blurring impair accuracy and precision of plaque measurements. The aim of the study was to evaluate MDCT post-processing based on non-linear image deblurring and edge-preserving noise suppression for measurements of plaque size. Contrast-enhanced MDCT coronary angiography was performed in four subjects (mean age 55 ± 5 years, mean heart rate 54 ± 5 bpm) using a 16-slice scanner (Siemens Sensation 16, collimation 16 x 0.75 mm, gantry rotation 420 ms, tube voltage 120 kV, tube current 550 mAs, 80 mL of contrast). Intravascular ultrasound (IVUS; 40 MHz probe) was performed in one vessel in each patient and served as a reference standard. MDCT vessel cross-sectional images (1 mm thickness) were created perpendicular to centerline and aligned with corresponding IVUS images. MDCT images were processed using a deblurring and edge-preserving noise suppression algorithm. Then, three independent blinded observers segmented lumen and outer vessel boundaries in each modality to obtain vessel cross-sectional area and wall area in the unprocessed MDCT cross-sections, post-processed MDCT cross-sections and corresponding IVUS. The wall area measurement difference for unprocessed and post-processed MDCT images relative to IVUS was 0.4 ± 3.8 mm 2 and -0.2 ± 2.2 mm 2 (p 2 , respectively. In conclusion, MDCT permitted accurate in vivo measurement of wall area and vessel cross-sectional area as compared to IVUS. Post-processing to reduce blurring and noise reduced variability of wall area measurements and reduced measurement bias for both wall area and vessel cross-sectional area

  11. Contrast-enhanced time-resolved 4D MRA of congenital heart and vessel anomalies: image quality and diagnostic value compared with 3D MRA

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, Florian M.; Hunold, Peter; Barkhausen, Joerg [University Hospital Schleswig-Holstein, Clinic for Radiology and Nuclear Medicine, Luebeck (Germany); Theysohn, Jens M.; Kinner, Sonja [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Michna, Dariusz [Elisabeth Hospital, Department of Neonatology, Essen (Germany); Neudorf, Ulrich [University Hospital Essen, Clinic for Pediatrics III, Essen (Germany); Quick, Harald H. [University of Erlangen-Nuernberg, Institute of Medical Physics, Erlangen (Germany)

    2013-09-15

    To evaluate time-resolved interleaved stochastic trajectories (TWIST) contrast-enhanced 4D magnetic resonance angiography (MRA) and compare it with 3D FLASH MRA in patients with congenital heart and vessel anomalies. Twenty-six patients with congenital heart and vessel anomalies underwent contrast-enhanced MRA with both 3D FLASH and 4D TWIST MRA. Images were subjectively evaluated regarding total image quality, artefacts, diagnostic value and added diagnostic value of 4D dynamic imaging. Quantitative comparison included signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and vessel sharpness measurements. Three-dimensional FLASH MRA was judged to be significantly better in terms of image quality (4.0 {+-} 0.6 vs 3.4 {+-} 0.6, P < 0.05) and artefacts (3.8 {+-} 0.4 vs 3.3 {+-} 0.5, P < 0.05); no difference in diagnostic value was found (4.2 {+-} 0.4 vs 4.0 {+-} 0.4); important additional functional information was found in 21/26 patients. SNR and CNR were higher in the pulmonary trunk in 4D TWIST, but slightly higher in the systemic arteries in 3D FLASH. No difference in vessel sharpness delineation was found. Although image quality was inferior compared with 3D FLASH MRA, 4D TWIST MRA yields robust images and added diagnostic value through dynamic acquisition was found. Thus, 4D TWIST MRA is an attractive alternative to 3D FLASH MRA. (orig.)

  12. Blood Vessel Extraction in Color Retinal Fundus Images with Enhancement Filtering and Unsupervised Classification

    Directory of Open Access Journals (Sweden)

    Zafer Yavuz

    2017-01-01

    Full Text Available Retinal blood vessels have a significant role in the diagnosis and treatment of various retinal diseases such as diabetic retinopathy, glaucoma, arteriosclerosis, and hypertension. For this reason, retinal vasculature extraction is important in order to help specialists for the diagnosis and treatment of systematic diseases. In this paper, a novel approach is developed to extract retinal blood vessel network. Our method comprises four stages: (1 preprocessing stage in order to prepare dataset for segmentation; (2 an enhancement procedure including Gabor, Frangi, and Gauss filters obtained separately before a top-hat transform; (3 a hard and soft clustering stage which includes K-means and Fuzzy C-means (FCM in order to get binary vessel map; and (4 a postprocessing step which removes falsely segmented isolated regions. The method is tested on color retinal images obtained from STARE and DRIVE databases which are available online. As a result, Gabor filter followed by K-means clustering method achieves 95.94% and 95.71% of accuracy for STARE and DRIVE databases, respectively, which are acceptable for diagnosis systems.

  13. Clinical Spectrum of Medium-Sized Vessel Vasculitis.

    Science.gov (United States)

    Alibaz-Oner, Fatma; Koster, Matthew J; Crowson, Cynthia S; Makol, Ashima; Ytterberg, Steven R; Salvarani, Carlo; Matteson, Eric L; Warrington, Kenneth J

    2017-06-01

    Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis of medium-sized visceral vessels. However, cutaneous arteritis (CA) and gastrointestinal (GI) vasculitis are forms of single-organ vasculitis having indistinguishable histopathologic findings from PAN. The aim of this study was to evaluate and compare the clinical characteristics, treatment, and outcomes of patients with systemic PAN, CA, and GI vasculitis. Retrospective cohorts were assembled, consisting of patients with PAN, CA, and GI vasculitis between 1980 and 2014. The demographics, clinical characteristics, treatment, and outcomes of patients were abstracted from medical records. We included 48 patients with PAN, 41 patients with CA, and 19 patients with GI vasculitis. The disease of 1 patient evolved from CA to systemic PAN during the disease course. At diagnosis, 94% of patients with PAN, 93% of patients with CA, and 67% of patients with GI vasculitis were treated with glucocorticoids. Additional immunosuppressive agents were used in 67% of PAN, 37% of GI vasculitis, and 32% of CA cases. The 5-year cumulative relapse rate was 45.2% in CA, and only 9.6% in PAN during a followup of approximately 6 years. No deaths were observed in the CA group. The survival rate at 10 years was 66% in the PAN group and 61% in the GI vasculitis group. Systemic PAN, CA, and GI vasculitis take different clinical courses and therefore may be different diseases, rather than existing on a spectrum of the same disease. Progression of CA to systemic PAN is very rare. Relapse risk is low during followup in PAN. Patients with CA have a higher relapse rate than those with systemic PAN, possibly due to less use of immunosuppressive therapy in CA. © 2016, American College of Rheumatology.

  14. Processing of MRI images weighted in TOF for blood vessels analysis: 3-D reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez D, J.; Cordova F, T. [Universidad de Guanajuato, Campus Leon, Departamento de Ingenieria Fisica, Loma del Bosque No. 103, Lomas del Campestre, 37150 Leon, Guanajuato (Mexico); Cruz A, I., E-mail: hernandezdj.gto@gmail.com [CONACYT, Centro de Investigacion en Matematicas, A. C., Jalisco s/n, Col. Valenciana, 36000 Guanajuato, Gto. (Mexico)

    2015-10-15

    This paper presents a novel presents an approach based on differences of intensities for the identification of vascular structures in medical images from MRI studies of type time of flight method (TOF). The plating method hypothesis gave high intensities belonging to the vascular system image type TOF can be segmented by thresholding of the histogram. The enhanced vascular structures is performed using the filter Vesselness, upon completion of a decision based on fuzzy thresholding minimizes error in the selection of vascular structures. It will give a brief introduction to the vascular system problems and how the images have helped diagnosis, is summarized the physical history of the different imaging modalities and the evolution of digital images with computers. Segmentation and 3-D reconstruction became image type time of flight; these images are typically used in medical diagnosis of cerebrovascular diseases. The proposed method has less error in segmentation and reconstruction of volumes related to the vascular system, clear images and less noise compared with edge detection methods. (Author)

  15. Processing of MRI images weighted in TOF for blood vessels analysis: 3-D reconstruction

    International Nuclear Information System (INIS)

    Hernandez D, J.; Cordova F, T.; Cruz A, I.

    2015-10-01

    This paper presents a novel presents an approach based on differences of intensities for the identification of vascular structures in medical images from MRI studies of type time of flight method (TOF). The plating method hypothesis gave high intensities belonging to the vascular system image type TOF can be segmented by thresholding of the histogram. The enhanced vascular structures is performed using the filter Vesselness, upon completion of a decision based on fuzzy thresholding minimizes error in the selection of vascular structures. It will give a brief introduction to the vascular system problems and how the images have helped diagnosis, is summarized the physical history of the different imaging modalities and the evolution of digital images with computers. Segmentation and 3-D reconstruction became image type time of flight; these images are typically used in medical diagnosis of cerebrovascular diseases. The proposed method has less error in segmentation and reconstruction of volumes related to the vascular system, clear images and less noise compared with edge detection methods. (Author)

  16. Selecting suitable coherent processing time window lengths for ground-based ISAR imaging of cooperative sea vessels

    CSIR Research Space (South Africa)

    Abdul Gaffar, MY

    2009-09-01

    Full Text Available CPTWLs are needed for larger vessels in order to obtain ISAR images with the desired cross-range resolution. The effectiveness of the CPTWLs, suggested by the MACS algorithm, is shown using measured radar data. The suggested CPTWLs may also be used...

  17. Flaw distribution development from vessel ISI data

    International Nuclear Information System (INIS)

    Foulds, J.R.; Kennedy, E.L.; Basin, S.L.; Rosinski, S.T.

    1991-01-01

    Previous attempts to develop flaw distributions for use in the structural integrity evaluation of pressurized water reactor (PWR) vessels have aimed at the estimation of a ''generic'' distribution applicable to all vessels. In contrast, this paper describes the analysis of vessel-specific in-service inspection (ISI) data for the development of a flaw distribution reliably representative of the condition of the particular vessel inspected. The application of the methodology may be extended to other vessels, but has been primarily developed for PWR reactor vessels. For this study, the flaw data analyzed included data obtained from three recently performed PWR vessel ISIs and from laboratory inspection of selected weldment sections of the Midland reactor vessel. The variability in both the character of the reviewed data (size range of flaws, number of flaws) and the UT (ultrasonic test) inspection system performance identified a need for analyzing the inspection results on a vessel-, or data set-specific basis. For this purpose, traditional histogram-based methods were inadequate, and a new methodology that can accept a very small number of flaws (typical of vessel-specific ISI results) and that includes consideration of inspection system flaw detection reliability, flaw sizing accuracy and flaw detection threshold, was developed. Results of the application of the methodology to each of the four PWR reactor vessel cases studied are presented and discussed

  18. Nuclear reactor pressure vessel-specific flaw distribution development

    International Nuclear Information System (INIS)

    Rosinski, S.T.

    1992-01-01

    Vessel integrity predictions performed through fracture mechanics analysis of a pressurized thermal shock event have been shown to be significantly sensitive to the overall flaw distribution input. It has also been shown that modem vessel in-service inspection (ISI) results can be used for development of vessel flaw distribution(s) that are more representative of US vessels. This paper describes the development and application of a methodology to analyze ISI data for the purpose of flaw distribution determination. The resultant methodology considers detection reliability, flaw sizing accuracy, and flaw detection threshold in its application. Application of the methodology was then demonstrated using four recently acquired US PWR vessel inspection data sets. Throughout the program, new insight was obtained into several key inspection performance and vessel integrity prediction practice issues that will impact future vessel integrity evaluation. For example, the potential application of a vessel-specific flaw distribution now provides at least one method by which a vessel-specific reference flaw size applicable to pressure-temperature limit curves determination can be estimated. This paper will discuss the development and application of the methodology and the impact to future vessel integrity analyses

  19. Vessel Wall Inflammation of Takayasu Arteritis Detected by Contrast-Enhanced Magnetic Resonance Imaging: Association with Disease Distribution and Activity.

    Directory of Open Access Journals (Sweden)

    Yoko Kato

    Full Text Available The assessment of the distribution and activity of vessel wall inflammation is clinically important in patients with Takayasu arteritis. Magnetic resonance imaging (MRI is a useful tool, but the clinical utility of late gadolinium enhancement (LGE in Takayasu arteritis has yet to be determined. The aim of the present study was to evaluate the utility of LGE in assessing vessel wall inflammation and disease activity in Takayasu arteritis.We enrolled 49 patients with Takayasu arteritis who had undergone 1.5 T MRI. Patients were divided into Active (n = 19 and Inactive disease (n = 30 groups. The distribution of vessel wall inflammation using angiography and LGE was assessed by qualitative analysis. In 79% and 63% of patients in Active and Inactive groups, respectively, greater distribution of vessel wall inflammation was observed with LGE than with conventional angiography. MRI values of pre- and post-contrast signal-to-noise ratios (SNR, SNR increment (post-SNR minus pre-SNR, pre- and post-contrast contrast-to-noise ratios (CNR, and CNR increment (post-CNR minus pre-CNR were evaluated at arterial wall sites with the highest signal intensity using quantitative analysis of post-contrast LGE images. No statistically significant differences in MRI parameters were observed between Active and Inactive groups. Contrast-enhanced MRI was unable to accurately detect active disease.Contrast-enhanced MRI has utility in detecting the distribution of vessel wall inflammation but has less utility in assessing disease activity in Takayasu arteritis.

  20. LANL Robotic Vessel Scanning

    Energy Technology Data Exchange (ETDEWEB)

    Webber, Nels W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-25

    Los Alamos National Laboratory in J-1 DARHT Operations Group uses 6ft spherical vessels to contain hazardous materials produced in a hydrodynamic experiment. These contaminated vessels must be analyzed by means of a worker entering the vessel to locate, measure, and document every penetration mark on the vessel. If the worker can be replaced by a highly automated robotic system with a high precision scanner, it will eliminate the risks to the worker and provide management with an accurate 3D model of the vessel presenting the existing damage with the flexibility to manipulate the model for better and more in-depth assessment.The project was successful in meeting the primary goal of installing an automated system which scanned a 6ft vessel with an elapsed time of 45 minutes. This robotic system reduces the total time for the original scope of work by 75 minutes and results in excellent data accumulation and transmission to the 3D model imaging program.

  1. Fine-grained visual marine vessel classification for coastal surveillance and defense applications

    Science.gov (United States)

    Solmaz, Berkan; Gundogdu, Erhan; Karaman, Kaan; Yücesoy, Veysel; Koç, Aykut

    2017-10-01

    The need for capabilities of automated visual content analysis has substantially increased due to presence of large number of images captured by surveillance cameras. With a focus on development of practical methods for extracting effective visual data representations, deep neural network based representations have received great attention due to their success in visual categorization of generic images. For fine-grained image categorization, a closely related yet a more challenging research problem compared to generic image categorization due to high visual similarities within subgroups, diverse applications were developed such as classifying images of vehicles, birds, food and plants. Here, we propose the use of deep neural network based representations for categorizing and identifying marine vessels for defense and security applications. First, we gather a large number of marine vessel images via online sources grouping them into four coarse categories; naval, civil, commercial and service vessels. Next, we subgroup naval vessels into fine categories such as corvettes, frigates and submarines. For distinguishing images, we extract state-of-the-art deep visual representations and train support-vector-machines. Furthermore, we fine tune deep representations for marine vessel images. Experiments address two scenarios, classification and verification of naval marine vessels. Classification experiment aims coarse categorization, as well as learning models of fine categories. Verification experiment embroils identification of specific naval vessels by revealing if a pair of images belongs to identical marine vessels by the help of learnt deep representations. Obtaining promising performance, we believe these presented capabilities would be essential components of future coastal and on-board surveillance systems.

  2. Distribution of different sized ocular surface vessels in diabetics and normal individuals

    Directory of Open Access Journals (Sweden)

    Touka Banaee

    2017-01-01

    Conclusion: Presence of diabetes mellitus is associated with contraction of larger vessels in the conjunctiva. Smaller vessels dilate with diabetic retinopathy. These findings may be useful in the photographic screening of diabetes mellitus and retinopathy.

  3. Automatic segmentation and 3D reconstruction of intravascular ultrasound images for a fast preliminar evaluation of vessel pathologies.

    Science.gov (United States)

    Sanz-Requena, Roberto; Moratal, David; García-Sánchez, Diego Ramón; Bodí, Vicente; Rieta, José Joaquín; Sanchis, Juan Manuel

    2007-03-01

    Intravascular ultrasound (IVUS) imaging is used along with X-ray coronary angiography to detect vessel pathologies. Manual analysis of IVUS images is slow and time-consuming and it is not feasible for clinical purposes. A semi-automated method is proposed to generate 3D reconstructions from IVUS video sequences, so that a fast diagnose can be easily done, quantifying plaque length and severity as well as plaque volume of the vessels under study. The methodology described in this work has four steps: a pre-processing of IVUS images, a segmentation of media-adventitia contour, a detection of intima and plaque and a 3D reconstruction of the vessel. Preprocessing is intended to remove noise from the images without blurring the edges. Segmentation of media-adventitia contour is achieved using active contours (snakes). In particular, we use the gradient vector flow (GVF) as external force for the snakes. The detection of lumen border is obtained taking into account gray-level information of the inner part of the previously detected contours. A knowledge-based approach is used to determine which level of gray corresponds statistically to the different regions of interest: intima, plaque and lumen. The catheter region is automatically discarded. An estimate of plaque type is also given. Finally, 3D reconstruction of all detected regions is made. The suitability of this methodology has been verified for the analysis and visualization of plaque length, stenosis severity, automatic detection of the most problematic regions, calculus of plaque volumes and a preliminary estimation of plaque type obtaining for automatic measures of lumen and vessel area an average error smaller than 1mm(2) (equivalent aproximately to 10% of the average measure), for calculus of plaque and lumen volume errors smaller than 0.5mm(3) (equivalent approximately to 20% of the average measure) and for plaque type estimates a mismatch of less than 8% in the analysed frames.

  4. Quantification of Tumor Vessels in Glioblastoma Patients Using Time-of-Flight Angiography at 7 Tesla: A Feasibility Study

    Science.gov (United States)

    Radbruch, Alexander; Eidel, Oliver; Wiestler, Benedikt; Paech, Daniel; Burth, Sina; Kickingereder, Philipp; Nowosielski, Martha; Bäumer, Philipp; Wick, Wolfgang; Schlemmer, Heinz-Peter; Bendszus, Martin; Ladd, Mark; Nagel, Armin Michael; Heiland, Sabine

    2014-01-01

    Purpose To analyze if tumor vessels can be visualized, segmented and quantified in glioblastoma patients with time of flight (ToF) angiography at 7 Tesla and multiscale vessel enhancement filtering. Materials and Methods Twelve patients with newly diagnosed glioblastoma were examined with ToF angiography (TR = 15 ms, TE = 4.8 ms, flip angle = 15°, FOV = 160×210 mm2, voxel size: 0.31×0.31×0.40 mm3) on a whole-body 7 T MR system. A volume of interest (VOI) was placed within the border of the contrast enhancing part on T1-weighted images of the glioblastoma and a reference VOI was placed in the non-affected contralateral white matter. Automated segmentation and quantification of vessels within the two VOIs was achieved using multiscale vessel enhancement filtering in ImageJ. Results Tumor vessels were clearly visible in all patients. When comparing tumor and the reference VOI, total vessel surface (45.3±13.9 mm2 vs. 29.0±21.0 mm2 (pTesla MRI enables characterization and quantification of the internal vascular morphology of glioblastoma and may be used for the evaluation of therapy response within future studies. PMID:25415327

  5. Feed particle size evaluation: conventional approach versus digital holography based image analysis

    Directory of Open Access Journals (Sweden)

    Vittorio Dell’Orto

    2010-01-01

    Full Text Available The aim of this study was to evaluate the application of image analysis approach based on digital holography in defining particle size in comparison with the sieve shaker method (sieving method as reference method. For this purpose ground corn meal was analyzed by a sieve shaker Retsch VS 1000 and by image analysis approach based on digital holography. Particle size from digital holography were compared with results obtained by screen (sieving analysis for each of size classes by a cumulative distribution plot. Comparison between particle size values obtained by sieving method and image analysis indicated that values were comparable in term of particle size information, introducing a potential application for digital holography and image analysis in feed industry.

  6. Application of morphological bit planes in retinal blood vessel extraction.

    Science.gov (United States)

    Fraz, M M; Basit, A; Barman, S A

    2013-04-01

    The appearance of the retinal blood vessels is an important diagnostic indicator of various clinical disorders of the eye and the body. Retinal blood vessels have been shown to provide evidence in terms of change in diameter, branching angles, or tortuosity, as a result of ophthalmic disease. This paper reports the development for an automated method for segmentation of blood vessels in retinal images. A unique combination of methods for retinal blood vessel skeleton detection and multidirectional morphological bit plane slicing is presented to extract the blood vessels from the color retinal images. The skeleton of main vessels is extracted by the application of directional differential operators and then evaluation of combination of derivative signs and average derivative values. Mathematical morphology has been materialized as a proficient technique for quantifying the retinal vasculature in ocular fundus images. A multidirectional top-hat operator with rotating structuring elements is used to emphasize the vessels in a particular direction, and information is extracted using bit plane slicing. An iterative region growing method is applied to integrate the main skeleton and the images resulting from bit plane slicing of vessel direction-dependent morphological filters. The approach is tested on two publicly available databases DRIVE and STARE. Average accuracy achieved by the proposed method is 0.9423 for both the databases with significant values of sensitivity and specificity also; the algorithm outperforms the second human observer in terms of precision of segmented vessel tree.

  7. An integrated 3-D image of cerebral blood vessels and CT view of tumor

    International Nuclear Information System (INIS)

    Suetens, P.; Baert, A.L.; Gybels, J.; Haegemans, S.; Jansen, P.; Oosterlinck, A.; Wilms, G.

    1984-01-01

    The authors developed a method that yields an integrated three-dimensional image of cerebral blood vessels and CT view of tumor. This method allows the neurosurgeon to choose any electrode trajectory that looks convenient to him, without imminent danger of causing a hemorrhage. Besides offering more safety to stereotactic interventions, this integrated 3-D image also has other applications. First, it gives a better characterization of most focal mass lesions seen by CT. Second, it allows high dose focal irradiation to be effected in such a way as to avoid arteries and veins. Third, it provides useful information for planning the strategy of open surgery

  8. X-ray image processing software for computing object size and object location coordinates from acquired optical and x-ray images

    International Nuclear Information System (INIS)

    Tiwari, Akash; Tiwari, Shyam Sunder; Tiwari, Railesha; Panday, Lokesh; Panday, Jeet; Suri, Nitin

    2004-01-01

    X-ray and Visible image data processing software has been developed in Visual Basic for real time online and offline image information processing for NDT and Medical Applications. Software computes two dimension image size parameters from its sharp boundary lines by raster scanning the image contrast data. Code accepts bit map image data and hunts for multiple tumors of different sizes that may be present in the image definition and then computes size of each tumor and locates its approximate center for registering its location coordinates. Presence of foreign metal and glass balls industrial product such as chocolate and other food items imaged out using x-ray imaging technique are detected by the software and their size and position co-ordinates are computed by the software. Paper discusses ways and means to compute size and coordinated of air bubble like objects present in the x-ray and optical images and their multiple existences in image of interest. (author)

  9. Why choroid vessels appear dark in clinical OCT images

    Science.gov (United States)

    Kirby, Mitchell A.; Li, Chenxi; Choi, Woo June; Gregori, Giovanni; Rosenfeld, Philip; Wang, Ruikang

    2018-02-01

    With the onset of clinically available spectral domain (SD-OCT) and swept source (SS-OCT) systems, clinicians are now easily able to recognize sub retinal microstructure and vascularization in the choroidal and scleral regions. As the bloodrich choroid supplies nutrients to the upper retinal layers, the ability to monitor choroid function accurately is of vital importance for clinical assessment of retinal health. However, the physical appearance of the choroid blood vessels (darker under a healthy Retinal Pigmented Epithelium (RPE) compared to regions displaying an RPE atrophic lesion) has led to confusion within the OCT ophthalmic community. The differences in appearance between each region in the OCT image may be interpreted as different vascular patterns when the vascular networks are in fact very similar. To explain this circumstance, we simulate light scattering phenomena in the RPE and Choroid complexes using the finite difference time domain (FDTD) method. The simulation results are then used to describe and validate imaging features in a controlled multi-layered tissue phantom designed to replicate human RPE, choroid, and whole blood microstructure. Essentially, the results indicate that the strength of the OCT signal from choroidal vasculature is dependent on the health and function of the RPE, and may not necessarily directly reflect the health and function of the choroidal vasculature.

  10. Imaging Blood Vessel Morphology in Skin

    DEFF Research Database (Denmark)

    Schuh, Sandra; Holmes, Jon; Ulrich, Martina

    2017-01-01

    Conventional optical coherence tomography (OCT) enables the visualization of morphological changes of skin cancer. The use of OCT in the diagnostic investigation and in the therapy decision of non-melanoma skin cancer and other skin changes is already established, and has found its way into routine...... practice. With the development of speckle-variance OCT, also named dynamic OCT (D-OCT), the vascular architecture and the blood flow of the skin can be displayed in vivo and in 3D. This novel angiographic variant of OCT offers the ability to visualize and measure vessel morphology providing a new insight...... into healthy, inflammatory and neoplastic skin lesions such as malignant melanoma. This review focuses on the possibilities of using D-OCT on healthy and diseased skin. We suggest and illustrate key diagnostic characteristics by analyzing the initial publications and preliminary unpublished data on vessel...

  11. Anatomy-based automatic detection and segmentation of major vessels in thoracic CTA images

    International Nuclear Information System (INIS)

    Zou Xiaotao; Liang Jianming; Wolf, M.; Salganicoff, M.; Krishnan, A.; Nadich, D.P.

    2007-01-01

    Existing approaches for automated computerized detection of pulmonary embolism (PE) using computed tomography angiography (CTA) usually focus on segmental and sub-segmental emboli. The goal of our current research is to extend our existing approach to automated detection of central PE. In order to detect central emboli, the major vessels must be first identified and segmented automatically. This submission presents an anatomy-based method for automatic computerized detection and segmentation of aortas and main pulmonary arteries in CTA images. (orig.)

  12. Analysis of toroidal vacuum vessels for use in demonstration sized tokamak reactors

    International Nuclear Information System (INIS)

    Culbert, M.E.

    1978-07-01

    The vacuum vessel component of the tokamak fusion reactor is the subject of this study. The main objective of this paper was to provide guidance for the structural design of a thin wall externally pressurized toroidal vacuum vessel. The analyses are based on the available state-of-the-art analytical methods. The shortcomings of these analytical methods necessitated approximations and assumptions to be made throughout the study. A principal result of the study has been the identification of a viable vacuum vessel design for the Demonstration Tokamak Hybrid Reactor (DTHR) and The Next Step (TNS) Reactor

  13. Three-dimensional surface reconstruction imaging for evaluation of congenital heart disease from ECG-triggered MR images

    International Nuclear Information System (INIS)

    Vannier, M.W.; Laschinger, J.; Knapp, R.H.; Gutierrez, F.R.; Gronnemeyer, S.A.

    1987-01-01

    Three-dimensional surface reconstruction images of the heart and great vessels were produced from contiguous sequences of electrocardiographically triggered MR images in 25 patients with congenital heart disease and in three healthy subjects. The imaging data were semiautomatically processed to separate the epicardial and endocardial surfaces and to define the outline of the enclosed blood volumes on a section by section basis. Images were obtained at 5-mm intervals in patients aged 3 months to 30 years with anomalies of the great vessels, tetralogy of Fallot, septal defects, pulmonary atresia, and other congenital heart malformations. The results were used to facilitate the surgical treatment of these patients and were compared with echocardiographic and cineradiographic studies, and with surgical findings or pathologic specimens. These surface reconstruction images were useful for communicating the results of diagnostic examinations to cardiac surgeons, for sizing and location of intracardiac defects, for imaging the pulmonary venous drainage, and for assessing regional and global function

  14. Confocal pore size measurement based on super-resolution image restoration.

    Science.gov (United States)

    Liu, Dali; Wang, Yun; Qiu, Lirong; Mao, Xinyue; Zhao, Weiqian

    2014-09-01

    A confocal pore size measurement based on super-resolution image restoration is proposed to obtain a fast and accurate measurement for submicrometer pore size of nuclear track-etched membranes (NTEMs). This method facilitates the online inspection of the pore size evolution during etching. Combining confocal microscopy with super-resolution image restoration significantly improves the lateral resolution of the NTEM image, yields a reasonable circle edge-setting criterion of 0.2408, and achieves precise pore edge detection. Theoretical analysis shows that the minimum measuring diameter can reach 0.19 μm, and the root mean square of the residuals is only 1.4 nm. Edge response simulation and experiment reveal that the edge response of the proposed method is better than 80 nm. The NTEM pore size measurement results obtained by the proposed method agree well with that obtained by scanning electron microscopy.

  15. Transformation of Image Positions, Rotations, and Sizes into Shift Parameters

    DEFF Research Database (Denmark)

    Skov Jensen, A.; Lindvold, L.; Rasmussen, E.

    1987-01-01

    An optical image processing system is described that converts orientation and size to shift properties and simultaneously preserves the positional information as a shift. The system is described analytically and experimentally. The transformed image can be processed further with a classical...... correlator working with a rotational and size-invariant. multiplexed match filter. An optical robot vision system designed on this concept would be able to look at several objects simultaneously and determine their shape, size, orientation, and position with two measurements on the input scene at different...

  16. Measurement of tumour size with mammography, sonography and magnetic resonance imaging as compared to histological tumour size in primary breast cancer

    International Nuclear Information System (INIS)

    Gruber, Ines V; Rueckert, Miriam; Kagan, Karl O; Staebler, Annette; Siegmann, Katja C; Hartkopf, Andreas; Wallwiener, Diethelm; Hahn, Markus

    2013-01-01

    Tumour size in breast cancer influences therapeutic decisions. The purpose of this study was to evaluate sizing of primary breast cancer using mammography, sonography and magnetic resonance imaging (MRI) and thereby establish which imaging method most accurately corresponds with the size of the histological result. Data from 121 patients with primary breast cancer were analysed in a retrospective study. The results were divided into the groups “ductal carcinoma in situ (DCIS)”, invasive ductal carcinoma (IDC) + ductal carcinoma in situ (DCIS)”, “invasive ductal carcinoma (IDC)”, “invasive lobular carcinoma (ILC)” and “other tumours” (tubular, medullary, mucinous and papillary breast cancer). The largest tumour diameter was chosen as the sizing reference in each case. Bland-Altman analysis was used to determine to what extent the imaging tumour size correlated with the histopathological tumour sizes. Tumour size was found to be significantly underestimated with sonography, especially for the tumour groups IDC + DCIS, IDC and ILC. The greatest difference between sonographic sizing and actual histological tumour size was found with invasive lobular breast cancer. There was no significant difference between mammographic and histological sizing. MRI overestimated non-significantly the tumour size and is superior to the other imaging techniques in sizing of IDC + DCIS and ILC. The histological subtype should be included in imaging interpretation for planning surgery in order to estimate the histological tumour size as accurately as possible

  17. Distribution of the In-Vessel Diagnostics in ITER Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    González, Jorge, E-mail: Jorge.Gonzalez@iter.org [Rüecker Lypsa, Carretera del Prat, 65, Cornellá de Llobregat (Spain); Clough, Matthew; Martin, Alex; Woods, Nick; Suarez, Alejandro [ITER Organization, Route de Vinon sur Verdon-CS 90 046 13067 Saint Paul Lez Durance (France); Martinez, Gonzalo [Technical University Of Catalonia (UPC), Barcelona-Tech, Barcelona (Spain); Stefan, Gicquel; Yunxing, Ma [ITER Organization, Route de Vinon sur Verdon-CS 90 046 13067 Saint Paul Lez Durance (France)

    2017-01-15

    The ITER In-Vessel Diagnostics have been distributed around the In-Vessel shell to understand burning plasma physics and assist in machine operation. Each diagnostics component has its own requirements, constraints, and even exclusion among them for the highly complex In-Vessel environment. The size of the plasma, the requirement to be able to align the blanket system to the magnetic centre of the machine, the cooling requirements of the blanket system and the size of the pressure vessel itself all add to the difficulties of integrating these systems into the remaining space available. The available space for the cables inside the special trays (in-Vessel looms) is another constraint to allocate In-Vessel electrical sensors. Besides this, there are issues with the Assembly sequences and surface & volumetric neutron heating considerations that have imposed several additional restrictions.

  18. Sum of top-hat transform based algorithm for vessel enhancement in MRA images

    Science.gov (United States)

    Ouazaa, Hibet-Allah; Jlassi, Hajer; Hamrouni, Kamel

    2018-04-01

    The Magnetic Resonance Angiography (MRA) is rich with information's. But, they suffer from poor contrast, illumination and noise. Thus, it is required to enhance the images. But, these significant information can be lost if improper techniques are applied. Therefore, in this paper, we propose a new method of enhancement. We applied firstly the CLAHE method to increase the contrast of the image. Then, we applied the sum of Top-Hat Transform to increase the brightness of vessels. It is performed with the structuring element oriented in different angles. The methodology is tested and evaluated on the publicly available database BRAINIX. And, we used the measurement methods MSE (Mean Square Error), PSNR (Peak Signal to Noise Ratio) and SNR (Signal to Noise Ratio) for the evaluation. The results demonstrate that the proposed method could efficiently enhance the image details and is comparable with state of the art algorithms. Hence, the proposed method could be broadly used in various applications.

  19. A contrast enhancement and scanning techniques for CT angiography of head and neck. One phase injection method for simultaneous imaging of vessels and tumor

    International Nuclear Information System (INIS)

    Morita, Yasuhiko; Indo, Hiroko; Noikura, Takenori

    1999-01-01

    We report on a method of CT-Angiography useful for examining lesion of the head and neck using three-dimensional images and measured CT value. This study focused on some of the important blood vessels in the head and neck. The aim of this method was to obtain high-contrast enhancement for both vessels and tumors at same time. A total amount of 100 ml nonionic contrast media (Omnipaque 240, 240 mg iodine per milliliter, Daiichi seiyaku, Tokyo, Japan) was injected intravenously with a flow of 1.5 ml/sec. Spiral scans, 24 rotations with 24 seconds, were started at a time when remaining amount of contrast media had become 30 to 20 ml. All CT scans were performed using double speed spiral scan technique with a slice thickness of 2 to 3 mm and table speeds from 3 to 5 mm/rotation. The patients populations consisted of 9 men and 6 women who ranged in age from 37 to 85 years. Sixteen CT-angiography were performed according to this method. Mean CT values of major blood vessels were measured in order to find out threshold at the level of submandibular gland in 13 examinations for 12 subjects. Important vessels like the common, internal, and the external artery, internal and external jugular vein were clearly visible in all subjects. Three dimensional images of these vessels could also be reconstructed for 15 of the subjects. Mean CT values were 211 Hounsfield units (HU) and 209 HU for the right and left internal carotid artery, respectively, and 204 HU and 206 HU for the right and left external carotid artery, respectively. Mean CT values for right and left internal jugular vein were 195 HU and 194 HU respectively. Measured CT values at each important blood vessels showed this method could yields acceptable enhancements. Good enhancement effect of tumor and blood vessels in the same scan seems to be mutually incompatible. One very important trade-off is the early enhancement effect at blood vessels versus the late enhancement effect at tumors. The other important trade

  20. An automated and robust image processing algorithm for glaucoma diagnosis from fundus images using novel blood vessel tracking and bend point detection.

    Science.gov (United States)

    M, Soorya; Issac, Ashish; Dutta, Malay Kishore

    2018-02-01

    Glaucoma is an ocular disease which can cause irreversible blindness. The disease is currently identified using specialized equipment operated by optometrists manually. The proposed work aims to provide an efficient imaging solution which can help in automating the process of Glaucoma diagnosis using computer vision techniques from digital fundus images. The proposed method segments the optic disc using a geometrical feature based strategic framework which improves the detection accuracy and makes the algorithm invariant to illumination and noise. Corner thresholding and point contour joining based novel methods are proposed to construct smooth contours of Optic Disc. Based on a clinical approach as used by ophthalmologist, the proposed algorithm tracks blood vessels inside the disc region and identifies the points at which first vessel bend from the optic disc boundary and connects them to obtain the contours of Optic Cup. The proposed method has been compared with the ground truth marked by the medical experts and the similarity parameters, used to determine the performance of the proposed method, have yield a high similarity of segmentation. The proposed method has achieved a macro-averaged f-score of 0.9485 and accuracy of 97.01% in correctly classifying fundus images. The proposed method is clinically significant and can be used for Glaucoma screening over a large population which will work in a real time. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Novel algorithm by low complexity filter on retinal vessel segmentation

    Science.gov (United States)

    Rostampour, Samad

    2011-10-01

    This article shows a new method to detect blood vessels in the retina by digital images. Retinal vessel segmentation is important for detection of side effect of diabetic disease, because diabetes can form new capillaries which are very brittle. The research has been done in two phases: preprocessing and processing. Preprocessing phase consists to apply a new filter that produces a suitable output. It shows vessels in dark color on white background and make a good difference between vessels and background. The complexity is very low and extra images are eliminated. The second phase is processing and used the method is called Bayesian. It is a built-in in supervision classification method. This method uses of mean and variance of intensity of pixels for calculate of probability. Finally Pixels of image are divided into two classes: vessels and background. Used images are related to the DRIVE database. After performing this operation, the calculation gives 95 percent of efficiency average. The method also was performed from an external sample DRIVE database which has retinopathy, and perfect result was obtained

  2. Optimization of the size and shape of the set-in nozzle for a PWR reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Murtaza, Usman Tariq, E-mail: maniiut@yahoo.com; Javed Hyder, M., E-mail: hyder@pieas.edu.pk

    2015-04-01

    Highlights: • The size and shape of the set-in nozzle of the RPV have been optimized. • The optimized nozzle ensure the reduction of the mass around 198 kg per nozzle. • The mass of the RPV should be minimized for better fracture toughness. - Abstract: The objective of this research work is to optimize the size and shape of the set-in nozzle for a typical reactor pressure vessel (RPV) of a 300 MW pressurized water reactor. The analysis was performed by optimizing the four design variables which control the size and shape of the nozzle. These variables are inner radius of the nozzle, thickness of the nozzle, taper angle at the nozzle-cylinder intersection, and the point where taper of the nozzle starts from. It is concluded that the optimum design of the nozzle is the one that minimizes the two conflicting state variables, i.e., the stress intensity (Tresca yield criterion) and the mass of the RPV.

  3. Robust shape regression for supervised vessel segmentation and its application to coronary segmentation in CTA

    DEFF Research Database (Denmark)

    Schaap, Michiel; van Walsum, Theo; Neefjes, Lisan

    2011-01-01

    This paper presents a vessel segmentation method which learns the geometry and appearance of vessels in medical images from annotated data and uses this knowledge to segment vessels in unseen images. Vessels are segmented in a coarse-to-fine fashion. First, the vessel boundaries are estimated...

  4. Automatic Segmentation of Vessels in In-Vivo Ultrasound Scans

    DEFF Research Database (Denmark)

    Tamimi-Sarnikowski, Philip; Brink-Kjær, Andreas; Moshavegh, Ramin

    2017-01-01

    presents a fully automatic segmentation algorithm, for robustly segmenting the vessel lumen in longitudinal B-mode ultrasound images. The automatic segmentation is performed using a combination of B-mode and power Doppler images. The proposed algorithm includes a series of preprocessing steps, and performs......Ultrasound has become highly popular to monitor atherosclerosis, by scanning the carotid artery. The screening involves measuring the thickness of the vessel wall and diameter of the lumen. An automatic segmentation of the vessel lumen, can enable the determination of lumen diameter. This paper...... a vessel segmentation by use of the marker-controlled watershed transform. The ultrasound images used in the study were acquired using the bk3000 ultrasound scanner (BK Ultrasound, Herlev, Denmark) with two transducers ”8L2 Linear” and ”10L2w Wide Linear” (BK Ultrasound, Herlev, Denmark). The algorithm...

  5. Efficacy of 'fine' focal spot imaging in CT abdominal angiography

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Lawrence Chia Wei; Devapalasundaram, Ashwini; Ardley, Nicholas [Monash Health, Department of Diagnostic Imaging, Clayton, Victoria (Australia); Lau, Kenneth K. [Monash Health, Department of Diagnostic Imaging, Clayton, Victoria (Australia); Monash University, Department of Medicine, Faculty of Medicine, Nursing, and Health Sciences, Victoria (Australia); Buchan, Kevin [Phillips Healthcare, Clinical Science, PO Box 312, Mont Albert, Victoria (Australia); Huynh, Minh [RMIT University, School of Mathematical and Geospatial Sciences, Victoria (Australia)

    2014-12-15

    To assess the efficacy of fine focal spot imaging in calcification beam-hardening artefact reduction and vessel clarity on CT abdominal angiography (CTAA). Adult patients of any age and gender who presented for CTAA were included. Thirty-nine patients were examined with a standard focal spot size (SFSS) of 1 x 1 mm in the first 3 months while 31 consecutive patients were examined with a fine focal spot size (FFSS) of 1 x 0.5 mm in the following 3 months. Vessel clarity and calcification beam-hardening artefacts of the abdominal aorta, celiac axis, superior mesenteric artery, inferior mesenteric artery, renal arteries, and iliac arteries were assessed using a 5-point grading scale by two blinded radiologists randomly. Cohen's Kappa test indicated that on average, there was substantial agreement among reviewers for vessel wall clarity and calcification artefact grading. Mann-Whitney test showed that there was a significant difference between the two groups, with FFSS performing significantly better for vessel clarity (U, 6481.50; p < 0.001; r, 0.73) and calcification artefact reduction (U, 1916; p < 0.001; r, 0.77). Fine focus CT angiography produces images with better vessel wall clarity and less vessel calcification beam-hardening artefact. (orig.)

  6. Customizable engineered blood vessels using 3D printed inserts.

    Science.gov (United States)

    Pinnock, Cameron B; Meier, Elizabeth M; Joshi, Neeraj N; Wu, Bin; Lam, Mai T

    2016-04-15

    Current techniques for tissue engineering blood vessels are not customizable for vascular size variation and vessel wall thickness. These critical parameters vary widely between the different arteries in the human body, and the ability to engineer vessels of varying sizes could increase capabilities for disease modeling and treatment options. We present an innovative method for producing customizable, tissue engineered, self-organizing vascular constructs by replicating a major structural component of blood vessels - the smooth muscle layer, or tunica media. We utilize a unique system combining 3D printed plate inserts to control construct size and shape, and cell sheets supported by a temporary fibrin hydrogel to encourage cellular self-organization into a tubular form resembling a natural artery. To form the vascular construct, 3D printed inserts are adhered to tissue culture plates, fibrin hydrogel is deposited around the inserts, and human aortic smooth muscle cells are then seeded atop the fibrin hydrogel. The gel, aided by the innate contractile properties of the smooth muscle cells, aggregates towards the center post insert, creating a tissue ring of smooth muscle cells. These rings are then stacked into the final tubular construct. Our methodology is robust, easily repeatable and allows for customization of cellular composition, vessel wall thickness, and length of the vessel construct merely by varying the size of the 3D printed inserts. This platform has potential for facilitating more accurate modeling of vascular pathology, serving as a drug discovery tool, or for vessel repair in disease treatment. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. The impact of image-size manipulation and sugar content on children's cereal consumption.

    Science.gov (United States)

    Neyens, E; Aerts, G; Smits, T

    2015-12-01

    Previous studies have demonstrated that portion sizes and food energy-density influence children's eating behavior. However, the potential effects of front-of-pack image-sizes of serving suggestions and sugar content have not been tested. Using a mixed experimental design among young children, this study examines the effects of image-size manipulation and sugar content on cereal and milk consumption. Children poured and consumed significantly more cereal and drank significantly more milk when exposed to a larger sized image of serving suggestion as compared to a smaller image-size. Sugar content showed no main effects. Nevertheless, cereal consumption only differed significantly between small and large image-sizes when sugar content was low. An advantage of this study was the mundane setting in which the data were collected: a school's dining room instead of an artificial lab. Future studies should include a control condition, with children eating by themselves to reflect an even more natural context. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Retinal blood vessel extraction using tunable bandpass filter and fuzzy conditional entropy.

    Science.gov (United States)

    Sil Kar, Sudeshna; Maity, Santi P

    2016-09-01

    Extraction of blood vessels on retinal images plays a significant role for screening of different opthalmologic diseases. However, accurate extraction of the entire and individual type of vessel silhouette from the noisy images with poorly illuminated background is a complicated task. To this aim, an integrated system design platform is suggested in this work for vessel extraction using a sequential bandpass filter followed by fuzzy conditional entropy maximization on matched filter response. At first noise is eliminated from the image under consideration through curvelet based denoising. To include the fine details and the relatively less thick vessel structures, the image is passed through a bank of sequential bandpass filter structure optimized for contrast enhancement. Fuzzy conditional entropy on matched filter response is then maximized to find the set of multiple optimal thresholds to extract the different types of vessel silhouettes from the background. Differential Evolution algorithm is used to determine the optimal gain in bandpass filter and the combination of the fuzzy parameters. Using the multiple thresholds, retinal image is classified as the thick, the medium and the thin vessels including neovascularization. Performance evaluated on different publicly available retinal image databases shows that the proposed method is very efficient in identifying the diverse types of vessels. Proposed method is also efficient in extracting the abnormal and the thin blood vessels in pathological retinal images. The average values of true positive rate, false positive rate and accuracy offered by the method is 76.32%, 1.99% and 96.28%, respectively for the DRIVE database and 72.82%, 2.6% and 96.16%, respectively for the STARE database. Simulation results demonstrate that the proposed method outperforms the existing methods in detecting the various types of vessels and the neovascularization structures. The combination of curvelet transform and tunable bandpass

  9. Macular Choroidal Small-Vessel Layer, Sattler's Layer and Haller's Layer Thicknesses: The Beijing Eye Study.

    Science.gov (United States)

    Zhao, Jing; Wang, Ya Xing; Zhang, Qi; Wei, Wen Bin; Xu, Liang; Jonas, Jost B

    2018-03-13

    To study macular choroidal layer thickness, 3187 study participants from the population-based Beijing Eye Study underwent spectral-domain optical coherence tomography with enhanced depth imaging for thickness measurements of the macular small-vessel layer, including the choriocapillaris, medium-sized choroidal vessel layer (Sattler's layer) and large choroidal vessel layer (Haller's layer). In multivariate analysis, greater thickness of all three choroidal layers was associated (all P  0.05) associated with the prevalence of open-angle glaucoma or diabetic retinopathy. There was a tendency (0.07 > P > 0.02) toward thinner choroidal layers in chronic angle-closure glaucoma. The ratio of small-vessel layer thickness to total choroidal thickness increased (P layer and Haller's layer thickness to total choroidal thickness decreased. A higher ratio of small-vessel layer thickness to total choroidal thickness was significantly associated with a lower prevalence of AMD (early type, intermediate type, late geographic type). Axial elongation-associated and aging-associated choroidal thinning affected Haller's and Sattler's layers more markedly than the small-vessel layer. Non-exudative and exudative AMD, except for geographic atrophy, was associated with slightly increased choroidal thickness.

  10. Size ratio correlates with intracranial aneurysm rupture status: a prospective study.

    Science.gov (United States)

    Rahman, Maryam; Smietana, Janel; Hauck, Erik; Hoh, Brian; Hopkins, Nick; Siddiqui, Adnan; Levy, Elad I; Meng, Hui; Mocco, J

    2010-05-01

    The prediction of intracranial aneurysm (IA) rupture risk has generated significant controversy. The findings of the International Study of Unruptured Intracranial Aneurysms (ISUIA) that small anterior circulation aneurysms (IAs are small. These discrepancies have led to the search for better aneurysm parameters to predict rupture. We previously reported that size ratio (SR), IA size divided by parent vessel diameter, correlated strongly with IA rupture status (ruptured versus unruptured). These data were all collected retrospectively off 3-dimensional angiographic images. Therefore, we performed a blinded prospective collection and evaluation of SR data from 2-dimensional angiographic images for a consecutive series of patients with ruptured and unruptured IAs. We prospectively enrolled 40 consecutive patients presenting to a single institution with either ruptured IA or for first-time evaluation of an incidental IA. Blinded technologists acquired all measurements from 2-dimensional angiographic images. Aneurysm rupture status, location, IA maximum size, and parent vessel diameter were documented. The SR was calculated by dividing the aneurysm size (mm) by the average parent vessel size (mm). A 2-tailed Mann-Whitney test was performed to assess statistical significance between ruptured and unruptured groups. Fisher exact test was used to compare medical comorbidities between the ruptured and unruptured groups. Significant differences between the 2 groups were subsequently tested with logistic regression. SE and probability values are reported. Forty consecutive patients with 24 unruptured and 16 ruptured aneurysms met the inclusion criteria. No significant differences were found in age, gender, smoking status, or medical comorbidities between ruptured and unruptured groups. The average maximum size of the unruptured IAs (6.18 + or - 0.60 mm) was significantly smaller compared with the ruptured IAs (7.91 + or - 0.47 mm; P=0.03), and the unruptured group had

  11. Size effects on failure behaviour of reactor pressure vessel steel and their dependence on deformation inhomogeneity

    International Nuclear Information System (INIS)

    Aktaa, J.; Klotz, M.; Schmitt, R.

    2003-01-01

    The investigation of the size dependence of the material behaviour and particularly of the failure strain is the main objective of the European research project LISSAC (Limit Strains for Severe Accident Conditions). Within our activities in LISSAC, tensile test series with specimens of similar geometry and different sizes are performed. The specimens, cut from the wall of a real reactor vessel, are flat with a central hole, flat with a double edge notch as well as round with a circumferential notch in order to obtain inhomogeneous deformation with high strain gradients, which will be higher in the smaller specimens and might be responsible for size effects. An additional variation of the strain gradient is obtained by varying the central hole radius of the flat specimens, with three different hole geometries being considered: round hole, increased round hole and slot. During the tests optical methods are used for measuring local deformations and partly local strain gradients. The results obtained show a size effect neither on the global nor on the local deformation behaviour, whereas the damage and failure behaviour is influenced significantly by the size of the specimen. On the basis of the surface deformation measurements, finite element calculations are performed to estimate the local failure strains as well as the corresponding strain gradients. A clear dependence of local failure strains on strain gradients is obtained. (author)

  12. Integral image rendering procedure for aberration correction and size measurement.

    Science.gov (United States)

    Sommer, Holger; Ihrig, Andreas; Ebenau, Melanie; Flühs, Dirk; Spaan, Bernhard; Eichmann, Marion

    2014-05-20

    The challenge in rendering integral images is to use as much information preserved by the light field as possible to reconstruct a captured scene in a three-dimensional way. We propose a rendering algorithm based on the projection of rays through a detailed simulation of the optical path, considering all the physical properties and locations of the optical elements. The rendered images contain information about the correct size of imaged objects without the need to calibrate the imaging device. Additionally, aberrations of the optical system may be corrected, depending on the setup of the integral imaging device. We show simulation data that illustrates the aberration correction ability and experimental data from our plenoptic camera, which illustrates the capability of our proposed algorithm to measure size and distance. We believe this rendering procedure will be useful in the future for three-dimensional ophthalmic imaging of the human retina.

  13. Determination of User Distribution Image Size and Position of Each Observation Area of Meteorological Imager in COMS

    Directory of Open Access Journals (Sweden)

    Jeong-Soo Seo

    2006-12-01

    Full Text Available In this paper, requirements of Meteorological Administration about Meteorological Imager (MI of Communications, Ocean and Meteorological Satellite (COMS is analyzed for the design of COMS ground station and according to the analysis results, the distribution image size of each observation area suitable for satellite Field Of View (FOV stated at the requirements of meteorological administration is determined and the precise satellite FOV and the size of distribution image is calculated on the basis of the image size of the determined observation area. The results in this paper were applied to the detailed design for COMS ground station and also are expected to be used for the future observation scheduling and the scheduling of distribution of user data.

  14. PWR vessel inspection performance improvements

    International Nuclear Information System (INIS)

    Blair Fairbrother, D.; Bodson, Francis

    1998-01-01

    A compact robot for ultrasonic inspection of reactor vessels has been developed that reduces setup logistics and schedule time for mandatory code inspections. Rather than installing a large structure to access the entire weld inspection area from its flange attachment, the compact robot examines welds in overlapping patches from a suction cup anchor to the shell wall. The compact robot size allows two robots to be operated in the vessel simultaneously. This significantly reduces the time required to complete the inspection. Experience to date indicates that time for vessel examinations can be reduced to fewer than four days. (author)

  15. Contrast-enhanced three-dimensional MR angiography of neck vessels: does dephasing effect alter diagnostic accuracy?

    International Nuclear Information System (INIS)

    Cosottini, M.; Calabrese, R.; Murri, L.; Puglioli, M.; Zampa, V.; Michelassi, M.C.; Ortori, S.; Bartolozzi, C.

    2003-01-01

    The aim of this study was to evaluate diagnostic accuracy of contrast-enhanced MRA (CEMRA) compared with digital subtraction angiography (DSA) in studying neck vessels of 48 patients. In three groups of patients, we used three MRA protocols differing for voxel size to assess if intravoxel dephasing effects could modify accuracy of CEMRA. Accuracy and correlation with DSA results were calculated in all patients and separately in the three groups. A qualitative analysis of the likeness between morphology of the stenosis in CEMRA and DSA images was also assessed. In all patients accuracy and agreement with DSA were 96% and k=0.85 in subclavian arteries, 96% and k=0.84 in vertebral artery, 97% and k=0.88 in common carotid arteries, and 94% and k=0.86 in internal carotid arteries. In the three groups accuracy and agreement with DSA did not show any significant difference. Qualitative analysis of CEMRA and DSA images revealed a better agreement in depicting the morphology of stenosis using a smaller voxel size. The CEMRA represents a powerful tool for the non-invasive evaluation of neck vessels. Overestimation trend of CEMRA is confirmed and the reduction of voxel size, decreasing the dephasing intravoxel effect, allows to have a better overlapping of stenosis morphology on CEMRA compared with DSA, but it does not yield diagnostic gain in the stenosis grading. (orig.)

  16. Vessel discoloration detection in malarial retinopathy

    Science.gov (United States)

    Agurto, C.; Nemeth, S.; Barriga, S.; Soliz, P.; MacCormick, I.; Taylor, T.; Harding, S.; Lewallen, S.; Joshi, V.

    2016-03-01

    Cerebral malaria (CM) is a life-threatening clinical syndrome associated with malarial infection. It affects approximately 200 million people, mostly sub-Saharan African children under five years of age. Malarial retinopathy (MR) is a condition in which lesions such as whitening and vessel discoloration that are highly specific to CM appear in the retina. Other unrelated diseases can present with symptoms similar to CM, therefore the exact nature of the clinical symptoms must be ascertained in order to avoid misdiagnosis, which can lead to inappropriate treatment and, potentially, death. In this paper we outline the first system to detect the presence of discolored vessels associated with MR as a means to improve the CM diagnosis. We modified and improved our previous vessel segmentation algorithm by incorporating the `a' channel of the CIELab color space and noise reduction. We then divided the segmented vasculature into vessel segments and extracted features at the wall and in the centerline of the segment. Finally, we used a regression classifier to sort the segments into discolored and not-discolored vessel classes. By counting the abnormal vessel segments in each image, we were able to divide the analyzed images into two groups: normal and presence of vessel discoloration due to MR. We achieved an accuracy of 85% with sensitivity of 94% and specificity of 67%. In clinical practice, this algorithm would be combined with other MR retinal pathology detection algorithms. Therefore, a high specificity can be achieved. By choosing a different operating point in the ROC curve, our system achieved sensitivity of 67% with specificity of 100%.

  17. A robust technique based on VLM and Frangi filter for retinal vessel extraction and denoising.

    Directory of Open Access Journals (Sweden)

    Khan Bahadar Khan

    Full Text Available The exploration of retinal vessel structure is colossally important on account of numerous diseases including stroke, Diabetic Retinopathy (DR and coronary heart diseases, which can damage the retinal vessel structure. The retinal vascular network is very hard to be extracted due to its spreading and diminishing geometry and contrast variation in an image. The proposed technique consists of unique parallel processes for denoising and extraction of blood vessels in retinal images. In the preprocessing section, an adaptive histogram equalization enhances dissimilarity between the vessels and the background and morphological top-hat filters are employed to eliminate macula and optic disc, etc. To remove local noise, the difference of images is computed from the top-hat filtered image and the high-boost filtered image. Frangi filter is applied at multi scale for the enhancement of vessels possessing diverse widths. Segmentation is performed by using improved Otsu thresholding on the high-boost filtered image and Frangi's enhanced image, separately. In the postprocessing steps, a Vessel Location Map (VLM is extracted by using raster to vector transformation. Postprocessing steps are employed in a novel way to reject misclassified vessel pixels. The final segmented image is obtained by using pixel-by-pixel AND operation between VLM and Frangi output image. The method has been rigorously analyzed on the STARE, DRIVE and HRF datasets.

  18. Carotid Intraplaque Hemorrhage Imaging with Quantitative Vessel Wall T1 Mapping: Technical Development and Initial Experience.

    Science.gov (United States)

    Qi, Haikun; Sun, Jie; Qiao, Huiyu; Chen, Shuo; Zhou, Zechen; Pan, Xinlei; Wang, Yishi; Zhao, Xihai; Li, Rui; Yuan, Chun; Chen, Huijun

    2018-04-01

    Purpose To develop a three-dimensional (3D) high-spatial-resolution time-efficient sequence for use in quantitative vessel wall T1 mapping. Materials and Methods A previously described sequence, simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) imaging, was extended by introducing 3D golden angle radial k-space sampling (GOAL-SNAP). Sliding window reconstruction was adopted to reconstruct images at different inversion delay times (different T1 contrasts) for voxelwise T1 fitting. Phantom studies were performed to test the accuracy of T1 mapping with GOAL-SNAP against a two-dimensional inversion recovery (IR) spin-echo (SE) sequence. In vivo studies were performed in six healthy volunteers (mean age, 27.8 years ± 3.0 [standard deviation]; age range, 24-32 years; five male) and five patients with atherosclerosis (mean age, 66.4 years ± 5.5; range, 60-73 years; five male) to compare T1 measurements between vessel wall sections (five per artery) with and without intraplaque hemorrhage (IPH). Statistical analyses included Pearson correlation coefficient, Bland-Altman analysis, and Wilcoxon rank-sum test with data permutation by subject. Results Phantom T1 measurements with GOAL-SNAP and IR SE sequences showed excellent correlation (R 2 = 0.99), with a mean bias of -25.8 msec ± 43.6 and a mean percentage error of 4.3% ± 2.5. Minimum T1 was significantly different between sections with IPH and those without it (mean, 371 msec ± 93 vs 944 msec ± 120; P = .01). Estimated T1 of normal vessel wall and muscle were 1195 msec ± 136 and 1117 msec ± 153, respectively. Conclusion High-spatial-resolution (0.8 mm isotropic) time-efficient (5 minutes) vessel wall T1 mapping is achieved by using the GOAL-SNAP sequence. This sequence may yield more quantitative reproducible biomarkers with which to characterize IPH and monitor its progression. © RSNA, 2017.

  19. Depiction of blood vessels by x-ray phase contrast

    Energy Technology Data Exchange (ETDEWEB)

    Momose, Atsushi [School of Engineering, University of Tokyo, Tokyo (Japan); Takeda, Tohoru; Itai, Yuji [Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Ibaraki (Japan)

    2001-04-01

    Blood vessels in livers of a mouse and a rat were depicted by phase-contrast x-ray imaging with an x-ray interferometer without using contrast agents. X-ray interference patterns were converted to image mapping x-ray phase shift caused by the livers using the technique of phase-shifting x-ray interferometry. The arteries and veins to and from the livers were tied before excision in order to prevent blood from flowing out of the liver. The x-ray phase shift caused by blood was substantially different from that caused by other soft sues, and consequently trees of blood vessels were revealed in the images. Vessels of diameter smaller than 0.1 mm were detected. This result suggests new possibilities for investigating vascular systems. (author)

  20. A universal approximation to grain size from images of non-cohesive sediment

    Science.gov (United States)

    Buscombe, D.; Rubin, D.M.; Warrick, J.A.

    2010-01-01

    The two-dimensional spectral decomposition of an image of sediment provides a direct statistical estimate, grid-by-number style, of the mean of all intermediate axes of all single particles within the image. We develop and test this new method which, unlike existing techniques, requires neither image processing algorithms for detection and measurement of individual grains, nor calibration. The only information required of the operator is the spatial resolution of the image. The method is tested with images of bed sediment from nine different sedimentary environments (five beaches, three rivers, and one continental shelf), across the range 0.1 mm to 150 mm, taken in air and underwater. Each population was photographed using a different camera and lighting conditions. We term it a “universal approximation” because it has produced accurate estimates for all populations we have tested it with, without calibration. We use three approaches (theory, computational experiments, and physical experiments) to both understand and explore the sensitivities and limits of this new method. Based on 443 samples, the root-mean-squared (RMS) error between size estimates from the new method and known mean grain size (obtained from point counts on the image) was found to be ±≈16%, with a 95% probability of estimates within ±31% of the true mean grain size (measured in a linear scale). The RMS error reduces to ≈11%, with a 95% probability of estimates within ±20% of the true mean grain size if point counts from a few images are used to correct bias for a specific population of sediment images. It thus appears it is transferable between sedimentary populations with different grain size, but factors such as particle shape and packing may introduce bias which may need to be calibrated for. For the first time, an attempt has been made to mathematically relate the spatial distribution of pixel intensity within the image of sediment to the grain size.

  1. Phase contrast MR imaging measurements of blood flow in healthy human cerebral vessel segments

    International Nuclear Information System (INIS)

    MacDonald, Matthew Ethan; Frayne, Richard

    2015-01-01

    Phase contrast (PC) magnetic resonance imaging was used to obtain velocity measurements in 30 healthy subjects to provide an assessment of hemodynamic parameters in cerebral vessels. We expect a lower coefficient-of-variation (COV) of the volume flow rate (VFR) compared to peak velocity (v_p_e_a_k) measurements and the COV to increase in smaller caliber arteries compared to large arteries.PC velocity maps were processed to calculate v_p_e_a_k and VFR in 26 vessel segments. The mean, standard deviation and COV, of v_p_e_a_k and VFR in each segment were calculated. A bootstrap-style analysis was used to determine the minimum number of subjects required to accurately represent the population. Significance of v_p_e_a_k and VFR asymmetry was assessed in 10 vessel pairs.The bootstrap analysis suggested that averaging more than 20 subjects would give consistent results. When averaged over the subjects, v_p_e_a_k and VFR ranged from 5.2 ± 7.1 cm s"−"1, 0.41 ± 0.58 ml s"−"1 (in the anterior communicating artery; mean ± standard deviation) to 73 ± 23 cm s"−"1, 7.6 ± 1.7 ml s"−"1 (in the left internal carotid artery), respectively. A tendency for VFR to be higher in the left hemisphere was observed in 88.8% of artery pairs, while the VFR in the right transverse sinus was larger. The VFR COV was larger than v_p_e_a_k COV in 57.7% of segments, while smaller vessels had higher COV.Significance and potential impact: VFR COV was not generally higher than v_p_e_a_k COV. COV was higher in smaller vessels as expected. These summarized values provide a base against which v_p_e_a_k and VFR in various disease states can be compared. (paper)

  2. Remote non-invasive stereoscopic imaging of blood vessels: first in-vivo results of a new multispectral contrast enhancement technology

    NARCIS (Netherlands)

    Wieringa, F.P.; Mastik, F.; Cate, F.J. ten; Neumann, H.A.M.; Steen, A.F.W. van der

    2006-01-01

    We describe a contactless optical technique selectively enhancing superficial blood vessels below variously pigmented intact human skin by combining images in different spectral bands. Two CMOS-cameras, with apochromatic lenses and dual-band LED-arrays, simultaneously streamed Left (L) and Right (R)

  3. Computational scalability of large size image dissemination

    Science.gov (United States)

    Kooper, Rob; Bajcsy, Peter

    2011-01-01

    We have investigated the computational scalability of image pyramid building needed for dissemination of very large image data. The sources of large images include high resolution microscopes and telescopes, remote sensing and airborne imaging, and high resolution scanners. The term 'large' is understood from a user perspective which means either larger than a display size or larger than a memory/disk to hold the image data. The application drivers for our work are digitization projects such as the Lincoln Papers project (each image scan is about 100-150MB or about 5000x8000 pixels with the total number to be around 200,000) and the UIUC library scanning project for historical maps from 17th and 18th century (smaller number but larger images). The goal of our work is understand computational scalability of the web-based dissemination using image pyramids for these large image scans, as well as the preservation aspects of the data. We report our computational benchmarks for (a) building image pyramids to be disseminated using the Microsoft Seadragon library, (b) a computation execution approach using hyper-threading to generate image pyramids and to utilize the underlying hardware, and (c) an image pyramid preservation approach using various hard drive configurations of Redundant Array of Independent Disks (RAID) drives for input/output operations. The benchmarks are obtained with a map (334.61 MB, JPEG format, 17591x15014 pixels). The discussion combines the speed and preservation objectives.

  4. Normal Indian pituitary gland size on MR imaging

    International Nuclear Information System (INIS)

    Gupta, A.K.; Jena, A.N.; Gulati, P.K.; Marwah, R.K.; Tripathi, R.P.; Sharma, R.K.; Khanna, C.M.

    1994-01-01

    The size of the pituitary gland was measured in 294 subjects, who had no known pituitary or hypothalamic disorders. Mid sagittal TIW images showing maximum dimensions of the pituitary gland, were used for measurement of the height in each age and sex group. The mean pituitary height of all the subjects in men was 5.3 mm (SD=0.9 mm), whereas in women, the mean height was 5.9 mm (SD = 1.2 mm). Beyond 10 years of age, the pituitary height measured was greater in women than in men. The gland height showed a gradual decrease with increasing age after the age of 30 years in both men and women except in the age group of 51-60 years, which showed paradoxical increase in size. The minimum gland height found in this study was 2.5 mm and the maximum, 8.8 mm. The study presents a demographic profile of pituitary gland size in north Indian subjects as measured on MR images. (author). 6 refs., 2 tabs., 1 fig

  5. Quantification of tumor vessels in glioblastoma patients using time-of-flight angiography at 7 Tesla: a feasibility study.

    Directory of Open Access Journals (Sweden)

    Alexander Radbruch

    Full Text Available PURPOSE: To analyze if tumor vessels can be visualized, segmented and quantified in glioblastoma patients with time of flight (ToF angiography at 7 Tesla and multiscale vessel enhancement filtering. MATERIALS AND METHODS: Twelve patients with newly diagnosed glioblastoma were examined with ToF angiography (TR = 15 ms, TE = 4.8 ms, flip angle = 15°, FOV = 160 × 210 mm(2, voxel size: 0.31 × 0.31 × 0.40 mm(3 on a whole-body 7 T MR system. A volume of interest (VOI was placed within the border of the contrast enhancing part on T1-weighted images of the glioblastoma and a reference VOI was placed in the non-affected contralateral white matter. Automated segmentation and quantification of vessels within the two VOIs was achieved using multiscale vessel enhancement filtering in ImageJ. RESULTS: Tumor vessels were clearly visible in all patients. When comparing tumor and the reference VOI, total vessel surface (45.3 ± 13.9 mm(2 vs. 29.0 ± 21.0 mm(2 (p<0.035 and number of branches (3.5 ± 1.8 vs. 1.0 ± 0.6 (p<0.001 per cubic centimeter were significantly higher, while mean vessel branch length was significantly lower (3.8 ± 1.5 mm vs 7.2 ± 2.8 mm (p<0.001 in the tumor. DISCUSSION: ToF angiography at 7-Tesla MRI enables characterization and quantification of the internal vascular morphology of glioblastoma and may be used for the evaluation of therapy response within future studies.

  6. Increase of cyclic durability of pressure vessels

    International Nuclear Information System (INIS)

    Vorona, V.A.; Zvezdin, Yu.I.

    1980-01-01

    The durability of multilayer pressure vessels under cyclic loading is compared with single-layer vessels. The relative conditional durability is calculated taking into account the assumption on the consequent destruction of layers and viewing a vessel wall as an indefinite plate. It is established that the durability is mainly determined by the number of layers and to a lesser degree depends on the relative size of the defect for the given layer thickness. The advantage of the multilayer vessels is the possibility of selecting layer materials so that to exclude the effect of agressive corrosion media on the strength [ru

  7. A low-cost, high-magnification imaging system for particle sizing applications

    International Nuclear Information System (INIS)

    Tipnis, Tanmay J; Lawson, Nicholas J; Tatam, Ralph P

    2014-01-01

    A low-cost imaging system for high magnification and high resolution was developed as an alternative to long-working-distance microscope-based systems, primarily for particle sizing applications. The imaging optics, comprising an inverted fixed focus lens coupled to a microscope objective, were able to provide a working distance of approximately 50 mm. The system magnification could be changed by using an appropriate microscope objective. Particle sizing was achieved using shadow-based techniques with the backlight illumination provided by a pulsed light-emitting diode light source. The images were analysed using commercial sizing software which gave the particle sizes and their distribution. A range of particles, from 6 to 8 µm to over 100 µm, was successfully measured with a minimum spatial resolution of approximately 2.5 µm. This system allowed measurement of a wide range of particles at a lower cost and improved operator safety without disturbing the flow. (technical design note)

  8. Size matters: Exploring the importance of vessel characteristics to inform estimates of shipping emissions

    International Nuclear Information System (INIS)

    Walsh, Conor; Bows, Alice

    2012-01-01

    Highlights: ► Ship emission baselines can be used to inform studies but require prior knowledge. ► Region specific conditions alter average shipping emission factors. ► Region specific conditions are clearer when individual callings are examined. ► Relationship between ship size and emissions frustrates estimating mean emissions. -- Abstract: The decarbonisation agenda is placing increasing pressure on retailers to directly and indirectly influence greenhouse gas emissions associated with full supply chains. Transportation by sea is an important and significant element of these supply chains, yet the emissions associated with shipping, particularly international shipping, are often poorly accounted for. The magnitude of emissions embodied in a product is directly related to the distances involved in globalised product chains, where shipping can represent the most emission intensive stage per tonne of goods transported. Specifically, limited choice of ship type and size within assessment tools negates a fair estimate of product chain emissions. To address this, the correlation between ship emissions and size is quantified for a sample of United Kingdom (UK) port callings to estimate typical UK emission factors by ship type and size and to determine how well existing global data and available databases represent UK shipping activity. The results highlight that although ship type is a crucial determinant of emissions, vessel size is also important, particularly for smaller ships where the variance in emission factors is greatest. Existing, globally averaged data correlating ship size with emissions agree well with the UK data. However, the relatively higher proportion of smaller ships satisfying a UK demand for short sea shipping results in a skew towards higher typical emission factors, principally within the general cargo, product and chemical tanker categories. This bias is most visible when emissions per individual ship calling are estimated. Incorporating

  9. Semi-automated retinal vessel analysis in nonmydriatic fundus photography.

    Science.gov (United States)

    Schuster, Alexander Karl-Georg; Fischer, Joachim Ernst; Vossmerbaeumer, Urs

    2014-02-01

    Funduscopic assessment of the retinal vessels may be used to assess the health status of microcirculation and as a component in the evaluation of cardiovascular risk factors. Typically, the evaluation is restricted to morphological appreciation without strict quantification. Our purpose was to develop and validate a software tool for semi-automated quantitative analysis of retinal vasculature in nonmydriatic fundus photography. matlab software was used to develop a semi-automated image recognition and analysis tool for the determination of the arterial-venous (A/V) ratio in the central vessel equivalent on 45° digital fundus photographs. Validity and reproducibility of the results were ascertained using nonmydriatic photographs of 50 eyes from 25 subjects recorded from a 3DOCT device (Topcon Corp.). Two hundred and thirty-three eyes of 121 healthy subjects were evaluated to define normative values. A software tool was developed using image thresholds for vessel recognition and vessel width calculation in a semi-automated three-step procedure: vessel recognition on the photograph and artery/vein designation, width measurement and calculation of central retinal vessel equivalents. Mean vessel recognition rate was 78%, vessel class designation rate 75% and reproducibility between 0.78 and 0.91. Mean A/V ratio was 0.84. Application on a healthy norm cohort showed high congruence with prior published manual methods. Processing time per image was one minute. Quantitative geometrical assessment of the retinal vasculature may be performed in a semi-automated manner using dedicated software tools. Yielding reproducible numerical data within a short time leap, this may contribute additional value to mere morphological estimates in the clinical evaluation of fundus photographs. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  10. X-ray tube focal spot sizes: comprehensive studies of their measurement and effect of measured size in angiography

    International Nuclear Information System (INIS)

    Doi, K.; Loo, L.N.; Chan, H.P.

    1982-01-01

    Thirty-two focal spot sizes of four x-ray tubes were measured by the pinhole, star pattern, slit, and root-mean-square (RMS) methods under various exposure conditions. The modulation transfer functions (MTFs) and line spread functions (LSFs) were also determined. The star pattern focal spot sizes agreed with the effective sizes calculated from the frequencies at the first minimum of the MTF within 0.04 mm for large focal spots and within 0.01 mm for small focal spots. The focal spot size determined by the slit method was approximately equal to the width of the LSF at the cutoff level of 0.15 +/- 0.06 of the peak value. The RMS method provided the best correlation between the measured focal spot sizes and the corresponding image distributions of blood vessels. The pinhole and slit methods tended to overestimate the focal spot size, but the star pattern method tended to underestimate it. For approximately 90% of the focal spots, the average of the star and slit (or pinhole) focal spot sizes agreed with the RMS focal spot size within +/- 0.1 mm

  11. Waif goodbye! Average-size female models promote positive body image and appeal to consumers.

    Science.gov (United States)

    Diedrichs, Phillippa C; Lee, Christina

    2011-10-01

    Despite consensus that exposure to media images of thin fashion models is associated with poor body image and disordered eating behaviours, few attempts have been made to enact change in the media. This study sought to investigate an effective alternative to current media imagery, by exploring the advertising effectiveness of average-size female fashion models, and their impact on the body image of both women and men. A sample of 171 women and 120 men were assigned to one of three advertisement conditions: no models, thin models and average-size models. Women and men rated average-size models as equally effective in advertisements as thin and no models. For women with average and high levels of internalisation of cultural beauty ideals, exposure to average-size female models was associated with a significantly more positive body image state in comparison to exposure to thin models and no models. For men reporting high levels of internalisation, exposure to average-size models was also associated with a more positive body image state in comparison to viewing thin models. These findings suggest that average-size female models can promote positive body image and appeal to consumers.

  12. Quantitative phase imaging characterization of tumor-associated blood vessel formation on a chip

    Science.gov (United States)

    Guo, Peng; Huang, Jing; Moses, Marsha A.

    2018-02-01

    Angiogenesis, the formation of new blood vessels from existing ones, is a biological process that has an essential role in solid tumor growth, development, and progression. Recent advances in Lab-on-a-Chip technology has created an opportunity for scientists to observe endothelial cell (EC) behaviors during the dynamic process of angiogenesis using a simple and economical in vitro platform that recapitulates in vivo blood vessel formation. Here, we use quantitative phase imaging (QPI) microscopy to continuously and non-invasively characterize the dynamic process of tumor cell-induced angiogenic sprout formation on a microfluidic chip. The live tumor cell-induced angiogenic sprouts are generated by multicellular endothelial sprouting into 3 dimensional (3D) Matrigel using human umbilical vein endothelial cells (HUVECs). By using QPI, we quantitatively measure a panel of cellular morphological and behavioral parameters of each individual EC participating in this sprouting. In this proof-of-principle study, we demonstrate that QPI is a powerful tool that can provide real-time quantitative analysis of biological processes in in vitro 3D biomimetic devices, which, in turn, can improve our understanding of the biology underlying functional tissue engineering.

  13. Effects of JPEG data compression on magnetic resonance imaging evaluation of small vessels ischemic lesions of the brain

    International Nuclear Information System (INIS)

    Kuriki, Paulo Eduardo de Aguiar; Abdala, Nitamar; Nogueira, Roberto Gomes; Carrete Junior, Henrique; Szejnfeld, Jacob

    2006-01-01

    Objective: to establish the maximum achievable JPEG compression ratio without affecting quantitative and qualitative magnetic resonance imaging analysis of ischemic lesion in small vessels of the brain. Material and method: fifteen DICOM images were converted to JPEG with a compression ratio of 1:10 to 1:60 and were assessed together with the original images by three neuro radiologists. The number, morphology and signal intensity of the lesions were analyzed. Results: lesions were properly identified up to a 1:30 ratio. More lesions were identified with a 1:10 ratio then in the original images. Morphology and edges were properly evaluated up toa 1:40 ratio. Compression did not affect signal. Conclusion: small lesions were identified ( < 2 mm ) and in all compression ratios the JPEG algorithm generated image noise that misled observers to identify more lesions in JPEG images then in DICOM images, thus generating false-positive results.(author)

  14. Proton density differences in signal characteristics of multiple sclerosis plaques versus white matter lesions of small vessel disease and vasculitis on high-field strength MR images

    International Nuclear Information System (INIS)

    Peyster, R.G.; Siegal, T.L.

    1990-01-01

    This paper determines if variations in signal intensity characteristics on multi-spin-echo images obtained with a high-field-strength magnet can be useful in differentiating demyelinating plaques of multiple sclerosis from other pathologic white matter processes due to small vessel disease and vasculities. Using the first of two multi-spin-echo images obtained with a General Electric 1.5-T magnet, the investigators compared signal intensity characteristics in 30 patients with a firm clinical diagnosis of multiple sclerosis versus a control group of 30 patients with a known clinical history of small-vessel disease and vasculitis are isodense to gray matter on proton-density images

  15. PWR vessel flaw distribution development

    International Nuclear Information System (INIS)

    Rosinski, S.T.; Kennedy, E.L.; Foulds, J.R.; Kinsman, K.M.

    1990-01-01

    This paper reports on PWR pressure vessels which operate under NRC rules and regulatory guides intended to prevent failure of the vessels. Plants failing to meet the operating criteria specified under these rules and regulations are required to analytically demonstrate fitness for service in order to continue operation. The initial flaw size or distribution of initial vessel flaws is a key input to the required vessel integrity analyses. However, the flaw distribution assumed in the development of the NRC Regulations and recommended for the plant specific analyses is potentially over-conservative. This is because the distribution is based on the limited amount of vessel inspection data available at the time the criteria were being developed and does not take full advantage of the more recent and reliable domestic vessel inspection results. The U.S. Department of Energy is funding an effort through Sandia National Laboratories to investigate the possibility of developing a new flaw distribution based on the increased amount and improved reliability of domestic vessel inspection data. Results of Phase I of the program indicate that state-of-the-art NDE systems' capabilities are sufficient for development of a new flaw distribution that could ultimately provide life extension benefits over the presently required operating practice

  16. Prosopomorphic vessels from Moesia Superior

    Directory of Open Access Journals (Sweden)

    Nikolić Snežana

    2008-01-01

    Full Text Available The prosopomorphic vessels from Moesia Superior had the form of beakers varying in outline but similar in size. They were wheel-thrown, mould-made or manufactured by using a combination of wheel-throwing and mould-made appliqués. Given that face vessels are considerably scarcer than other kinds of pottery, more than fifty finds from Moesia Superior make an enviable collection. In this and other provinces face vessels have been recovered from military camps, civilian settlements and necropolises, which suggests that they served more than one purpose. It is generally accepted that the faces-masks gave a protective role to the vessels, be it to protect the deceased or the family, their house and possessions. More than forty of all known finds from Moesia Superior come from Viminacium, a half of that number from necropolises. Although tangible evidence is lacking, there must have been several local workshops producing face vessels. The number and technological characteristics of the discovered vessels suggest that one of the workshops is likely to have been at Viminacium, an important pottery-making centre in the second and third centuries.

  17. Nuclear reactor pressure vessel flaw distribution development

    International Nuclear Information System (INIS)

    Kennedy, E.L.; Foulds, J.R.; Basin, S.L.

    1991-12-01

    Previous attempts to develop flaw distributions for probabilistic fracture mechanics analyses of pressurized water reactor (PWR) vessels have aimed at the estimation of a ''generic'' distribution applicable to all PWR vessels. In contrast, this report describes (1) a new flaw distribution development analytic methodology that can be applied to the analysis of vessel-specific inservice inspection (ISI) data, and (2) results of the application of the methodology to the analysis of flaw data for each vessel case (ISI data on three PWR vessels and laboratory inspection data on sections of the Midland reactor vessel). Results of this study show significant variation among the flaw distributions derived from the various data sets analyzed, strongly suggesting than a vessel-specific flaw distribution (for vessel integrity prediction under pressurized thermal shock) is preferred over a ''generic'' distribution. In addition, quantitative inspection system flaw sizing accuracy requirements have been identified for developing a flaw distribution from vessel ISI data. The new flaw data analysis methodology also permits quantifying the reliability of the flaw distribution estimate. Included in the report are identified needs for further development of several aspects of ISI data acquisition and vessel integrity prediction practice

  18. Erratum to: Ungersma SE, Pacheco G, Ho C, Yee SF, Ross J, van Bruggen N, Peale FV Jr, Ross S, Carano RA. Vessel imaging with viable tumor analysis for quantification of tumor angiogenesis. Magn Reson Med 2010;63:1637–1647.

    Science.gov (United States)

    Ungersma, Sharon E; Pacheco, Glenn; Ho, Calvin; Yee, Sharon Fong; Ross, Jed; van Bruggen, Nicholas; Peale, Franklin V; Ross, Sarajane; Carano, Richard A D

    2011-03-01

    Imaging of tumor microvasculature has become an important tool for studying angiogenesis and monitoring antiangiogenic therapies. Ultrasmall paramagnetic iron oxide contrast agents for indirect imaging of vasculature offer a method for quantitative measurements of vascular biomarkers such as vessel size index, blood volume, and vessel density (Q). Here, this technique is validated with direct comparisons to ex vivo micro-computed tomography angiography and histologic vessel measurements, showing significant correlations between in vivo vascular MRI measurements and ex vivo structural vessel measurements. The sensitivity of the MRI vascular parameters is also demonstrated, in combination with a multispectral analysis technique for segmenting tumor tissue to restrict the analysis to viable tumor tissue and exclude regions of necrosis. It is shown that this viable tumor segmentation increases sensitivity for detection of significant effects on blood volume and Q by two antiangiogenic therapeutics [anti-vascular endothelial growth factor (anti-VEGF) and anti-neuropilin-1] on an HM7 colorectal tumor model. Anti-vascular endothelial growth factor reduced blood volume by 36±3% (p<0.0001) and Q by 52±3% (p<0.0001) at 48 h post-treatment; the effects of anti-neuropilin-1 were roughly half as strong with a reduction in blood volume of 18±6% (p<0.05) and a reduction in Q of 33±5% (p<0.05) at 48 h post-treatment.

  19. Assessment of jeopardized myocardium in patients with one-vessel disease

    International Nuclear Information System (INIS)

    Iskandrian, A.S.; Lichtenberg, R.; Segal, B.L.; Mintz, G.S.; Mundth, E.D.; Hakki, A.-H.; Kimbiris, D.; Bemis, C.E.; Croll, M.N.; Kane, S.A.

    1982-01-01

    The size of the perfusion defect was assessed from a quantitative analysis of exercise thallium-201 images. Quantitative analysis was determined by measuring the area and the perimeter of the perfusion defect and expressing it as a percentage of the total left ventricular area or perimeter in three projections. Using this technique, we studied 50 patients with one-vessel disease of 50% or greater diameter narrowing. The planimetric and the perimetric methods correlated well (p<0.001, r=0.97). Of the 11 patients with less than 70% diameter narrowing, only one patient had abnormal exercise thallium-201 images. Of the remaining 39 patients with 70% or greater diameter narrowing, 35 had abnormal exercise images. The defects were larger in patients with left anterior descending coronary artery disease (33 +/- 10%; mean +/- SD by perimetry) than in patients with left circumflex coronary artery disease (19 +/- 14%, p<0.01) or right coronary artery disease (17 +/- 11%, p<0.01). There was also significant variation in the sizes of the defects in the three projections in patients with left circumflex and right coronary artery disease, but not in patients with left anterior descending coronary artery disease. Patients with left anterior descending coronary artery disease with collaterals had smaller defects than their counterparts without collaterals

  20. Optics based signal processing methods for intraoperative blood vessel detection and quantification in real time (Conference Presentation)

    Science.gov (United States)

    Chaturvedi, Amal; Shukair, Shetha A.; Le Rolland, Paul; Vijayvergia, Mayank; Subramanian, Hariharan; Gunn, Jonathan W.

    2016-03-01

    Minimally invasive operations require surgeons to make difficult cuts to blood vessels and other tissues with impaired tactile and visual feedback. This leads to inadvertent cuts to blood vessels hidden beneath tissue, causing serious health risks to patients and a non-reimbursable financial burden to hospitals. Intraoperative imaging technologies have been developed, but these expensive systems can be cumbersome and provide only a high-level view of blood vessel networks. In this research, we propose a lean reflectance-based system, comprised of a dual wavelength LED, photodiode, and novel signal processing algorithms for rapid vessel characterization. Since this system takes advantage of the inherent pulsatile light absorption characteristics of blood vessels, no contrast agent is required for its ability to detect the presence of a blood vessel buried deep inside any tissue type (up to a cm) in real time. Once a vessel is detected, the system is able to estimate the distance of the vessel from the probe and the diameter size of the vessel (with a resolution of ~2mm), as well as delineate the type of tissue surrounding the vessel. The system is low-cost, functions in real-time, and could be mounted on already existing surgical tools, such as Kittner dissectors or laparoscopic suction irrigation cannulae. Having been successfully validated ex vivo, this technology will next be tested in a live porcine study and eventually in clinical trials.

  1. Reducing catheter-related thrombosis using a risk reduction tool centered on catheter to vessel ratio.

    Science.gov (United States)

    Spencer, Timothy R; Mahoney, Keegan J

    2017-11-01

    In vascular access practices, the internal vessel size is considered important, and a catheter to vessel ratio (CVR) is recommended to assist clinicians in selecting the most appropriate-sized device for the vessel. In 2016, new practice recommendations stated that the CVR can increase from 33 to 45% of the vessels diameter. There has been evidence on larger diameter catheters and increased thrombosis risk in recent literature, while insufficient information established on what relationship to vessel size is appropriate for any intra-vascular device. Earlier references to clinical standards and guidelines did not clearly address vessel size in relation to the area consumed or external catheter diameter. The aim of this manuscript is to present catheter-related thrombosis evidence and develop a standardized process of ultrasound-guided vessel assessment, integrating CVR, Virchow's triad phenomenon and vessel health and preservation strategies, empowering an evidence-based approach to device placement. Through review, calculation and assessment on the areas of the 33 and 45% rule, a preliminary clinical tool was developed to assist clinicians make cognizant decisions when placing intravascular devices relating to target vessel size, focusing on potential reduction in catheter-related thrombosis. Increasing the understanding and utilization of CVRs will lead to a safer, more consistent approach to device placement, with potential thrombosis reduction strategies. The future of evidence-based data relies on the clinician to capture accurate vessel measurements and device-related outcomes. This will lead to a more dependable data pool, driving the relationship of catheter-related thrombosis and vascular assessment.

  2. Pressure vessel inspection criteria based on fitness-for-purpose assessment

    International Nuclear Information System (INIS)

    Grover, J.L.; Cipolla, R.C.

    1985-01-01

    The paper on pressure vessel inspection investigates the methodology required to establish an inspection strategy consistent with fracture mechanics analysis, i.e. to define allowable flaw sizes based on location within the vessel. The methodology is demonstrated using a sample problem for a typical pressurised water reactor pressure vessel, and shows the impact of certain assumptions on the inspection strategy. The results indicate that the flaw size varies with the shape of the assumed residual stress field and the through-thickness location. Also in general, the fracture mechanics evaluation allows flaws much larger than are allowed by the inspection acceptance criteria. (UK)

  3. Determining wood chip size: image analysis and clustering methods

    Directory of Open Access Journals (Sweden)

    Paolo Febbi

    2013-09-01

    Full Text Available One of the standard methods for the determination of the size distribution of wood chips is the oscillating screen method (EN 15149- 1:2010. Recent literature demonstrated how image analysis could return highly accurate measure of the dimensions defined for each individual particle, and could promote a new method depending on the geometrical shape to determine the chip size in a more accurate way. A sample of wood chips (8 litres was sieved through horizontally oscillating sieves, using five different screen hole diameters (3.15, 8, 16, 45, 63 mm; the wood chips were sorted in decreasing size classes and the mass of all fractions was used to determine the size distribution of the particles. Since the chip shape and size influence the sieving results, Wang’s theory, which concerns the geometric forms, was considered. A cluster analysis on the shape descriptors (Fourier descriptors and size descriptors (area, perimeter, Feret diameters, eccentricity was applied to observe the chips distribution. The UPGMA algorithm was applied on Euclidean distance. The obtained dendrogram shows a group separation according with the original three sieving fractions. A comparison has been made between the traditional sieve and clustering results. This preliminary result shows how the image analysis-based method has a high potential for the characterization of wood chip size distribution and could be further investigated. Moreover, this method could be implemented in an online detection machine for chips size characterization. An improvement of the results is expected by using supervised multivariate methods that utilize known class memberships. The main objective of the future activities will be to shift the analysis from a 2-dimensional method to a 3- dimensional acquisition process.

  4. Image-Based Computational Fluid Dynamics in Blood Vessel Models: Toward Developing a Prognostic Tool to Assess Cardiovascular Function Changes in Prolonged Space Flights

    Science.gov (United States)

    Chatzimavroudis, George P.; Spirka, Thomas A.; Setser, Randolph M.; Myers, Jerry G.

    2004-01-01

    One of NASA's objectives is to be able to perform a complete, pre-flight, evaluation of cardiovascular changes in astronauts scheduled for prolonged space missions. Computational fluid dynamics (CFD) has shown promise as a method for estimating cardiovascular function during reduced gravity conditions. For this purpose, MRI can provide geometrical information, to reconstruct vessel geometries, and measure all spatial velocity components, providing location specific boundary conditions. The objective of this study was to investigate the reliability of MRI-based model reconstruction and measured boundary conditions for CFD simulations. An aortic arch model and a carotid bifurcation model were scanned in a 1.5T Siemens MRI scanner. Axial MRI acquisitions provided images for geometry reconstruction (slice thickness 3 and 5 mm; pixel size 1x1 and 0.5x0.5 square millimeters). Velocity acquisitions provided measured inlet boundary conditions and localized three-directional steady-flow velocity data (0.7-3.0 L/min). The vessel walls were isolated using NIH provided software (ImageJ) and lofted to form the geometric surface. Constructed and idealized geometries were imported into a commercial CFD code for meshing and simulation. Contour and vector plots of the velocity showed identical features between the MRI velocity data, the MRI-based CFD data, and the idealized-geometry CFD data, with less than 10% differences in the local velocity values. CFD results on models reconstructed from different MRI resolution settings showed insignificant differences (less than 5%). This study illustrated, quantitatively, that reliable CFD simulations can be performed with MRI reconstructed models and gives evidence that a future, subject-specific, computational evaluation of the cardiovascular system alteration during space travel is feasible.

  5. Rose Bengal Photothrombosis by Confocal Optical Imaging In Vivo: A Model of Single Vessel Stroke.

    Science.gov (United States)

    Talley Watts, Lora; Zheng, Wei; Garling, R Justin; Frohlich, Victoria C; Lechleiter, James Donald

    2015-06-23

    In vivo imaging techniques have increased in utilization due to recent advances in imaging dyes and optical technologies, allowing for the ability to image cellular events in an intact animal. Additionally, the ability to induce physiological disease states such as stroke in vivo increases its utility. The technique described herein allows for physiological assessment of cellular responses within the CNS following a stroke and can be adapted for other pathological conditions being studied. The technique presented uses laser excitation of the photosensitive dye Rose Bengal in vivo to induce a focal ischemic event in a single blood vessel. The video protocol demonstrates the preparation of a thin-skulled cranial window over the somatosensory cortex in a mouse for the induction of a Rose Bengal photothrombotic event keeping injury to the underlying dura matter and brain at a minimum. Surgical preparation is initially performed under a dissecting microscope with a custom-made surgical/imaging platform, which is then transferred to a confocal microscope equipped with an inverted objective adaptor. Representative images acquired utilizing this protocol are presented as well as time-lapse sequences of stroke induction. This technique is powerful in that the same area can be imaged repeatedly on subsequent days facilitating longitudinal in vivo studies of pathological processes following stroke.

  6. Pediatric ureteropelvic junction obstruction: can magnetic resonance urography identify crossing vessels?

    Energy Technology Data Exchange (ETDEWEB)

    Parikh, Kushal R.; Kraft, Kate H.; Ivancic, Vesna; Smith, Ethan A.; Dillman, Jonathan R. [Section of Pediatric Radiology, Mott Children' s Hospital, Department of Radiology, University of Michigan Health System, Ann Arbor, MI (United States); Hammer, Matthew R. [University of Texas Southwestern, Department of Radiology, Dallas, TX (United States)

    2015-11-15

    MR Urography (MRU) is an increasingly used imaging modality for the evaluation of pediatric genitourinary obstruction. To determine whether pediatric MR urography (MRU) reliably detects crossing vessels in the setting of suspected ureteropelvic junction (UPJ) obstruction. The clinical significance of these vessels was also evaluated. We identified pediatric patients diagnosed with UPJ obstruction by MRU between May 2009 and June 2014. MRU studies were evaluated by two pediatric radiologists for the presence or absence of crossing vessels. Ancillary imaging findings such as laterality, parenchymal thinning/scarring, trapped fluid in the proximal ureter, and presence of renal parenchymal edema were also evaluated. Imaging findings were compared to surgical findings. We used the Mann-Whitney U test to compare continuous data and the Fisher exact test to compare proportions. Twenty-four of 25 (96%) UPJ obstructions identified by MRU were surgically confirmed. MRU identified crossing vessels in 10 of these cases, with 9 cases confirmed intraoperatively (κ = 0.92 [95% CI: 0.75, 1.0]). Crossing vessels were determined to be the primary cause of UPJ obstruction in 7/9 children intraoperatively, while in two children the vessels were deemed incidental and noncontributory to the urinary tract obstruction. There was no significant difference in age or the proportions of ancillary findings when comparing children without and with obstructing vessels. MRU allows detection of crossing vessels in pediatric UPJ obstruction. Although these vessels are the primary cause of obstruction in some children, they are incidental and non-contributory in others. Our study failed to convincingly identify any significant predictors (e.g., age or presence of renal parenchymal edema) that indicate when a crossing vessel is the primary cause of obstruction. (orig.)

  7. Accuracy and initial clinical experience with measurement software (advanced vessel analysis) in three-dimensional imaging

    International Nuclear Information System (INIS)

    Abe, Toshi; Hirohata, Masaru; Tanigawa, Hitoshi

    2002-01-01

    Recently, the clinical benefits of three dimensional (3D) imaging, such as 3D-CTA and 3D-DSA, in cerebro-vascular disease have been widely recognized. Software for quantitative analysis of vascular structure in 3D imaging (advanced vessel analysis: AVA) has been developed. We evaluated AVA with both phantom studies and a few clinical cases. In spiral and curvy aluminum tube phantom studies, the accuracy of diameter measurements was good in 3D images produced from data set generated by multi-detector row CT or rotational angiography. The measurement error was less than 0.03 mm on aluminum tube phantoms that were 3 mm and 5 mm in diameter. In the clinical studies, the differences of carotid artery diameter measurements between 2D-DSA and 3D-DSA was less than 0.3 mm in. The measurement of length, diameter and angle by AVA should provide useful information for planning surgical and endovascular treatments of cerebro-vascular disease. (author)

  8. Optimizing CT radiation dose based on patient size and image quality: the size-specific dose estimate method

    Energy Technology Data Exchange (ETDEWEB)

    Larson, David B. [Stanford University School of Medicine, Department of Radiology, Stanford, CA (United States)

    2014-10-15

    The principle of ALARA (dose as low as reasonably achievable) calls for dose optimization rather than dose reduction, per se. Optimization of CT radiation dose is accomplished by producing images of acceptable diagnostic image quality using the lowest dose method available. Because it is image quality that constrains the dose, CT dose optimization is primarily a problem of image quality rather than radiation dose. Therefore, the primary focus in CT radiation dose optimization should be on image quality. However, no reliable direct measure of image quality has been developed for routine clinical practice. Until such measures become available, size-specific dose estimates (SSDE) can be used as a reasonable image-quality estimate. The SSDE method of radiation dose optimization for CT abdomen and pelvis consists of plotting SSDE for a sample of examinations as a function of patient size, establishing an SSDE threshold curve based on radiologists' assessment of image quality, and modifying protocols to consistently produce doses that are slightly above the threshold SSDE curve. Challenges in operationalizing CT radiation dose optimization include data gathering and monitoring, managing the complexities of the numerous protocols, scanners and operators, and understanding the relationship of the automated tube current modulation (ATCM) parameters to image quality. Because CT manufacturers currently maintain their ATCM algorithms as secret for proprietary reasons, prospective modeling of SSDE for patient populations is not possible without reverse engineering the ATCM algorithm and, hence, optimization by this method requires a trial-and-error approach. (orig.)

  9. Photometric imaging in particle size measurement and surface visualization.

    Science.gov (United States)

    Sandler, Niklas

    2011-09-30

    The aim of this paper is to give an insight into photometric particle sizing approaches, which differ from the typical particle size measurement of dispersed particles. These approaches can often be advantageous especially for samples that are moist or cohesive, when dispersion of particles is difficult or sometimes impossible. The main focus of this paper is in the use of photometric stereo imaging. The technique allows the reconstruction of three-dimensional images of objects using multiple light sources in illumination. The use of photometric techniques is demonstrated in at-line measurement of granules and on-line measurement during granulation and dry milling. Also, surface visualization and roughness measurements are briefly discussed. Copyright © 2010 Elsevier B.V. All rights reserved.

  10. Investigation of flow stabilization in a compact reactor vessel of a FBR. Flow visualization in a reactor vessel

    International Nuclear Information System (INIS)

    Sato, Hiroyuki; Igarashi, Minoru; Kimura, Nobuyuki; Kamide, Hideki

    2002-01-01

    In the feasibility studies of Commercialized Fast Breeder Reactor Cycle System, a compact reactor vessel is considered from economical improvement point of a sodium cooled loop type fast reactor. The flow field was visualized by water experiment for a reactor vessel with 'a column type UIS (Upper Internal Structure)', which has a slit for fuel handling mechanism and is useful for a compact fast reactor. In this research, the 1/20 scale test equipment using water was made to understand coolant flow through a slit of a column type UIS' and fundamental behavior of reactor upper plenum flow. In the flow visualization tests, tracer particles were added in the water, and illuminated by the slit-shaped pulse laser. The flow visualization image was taken with a CCD camera. We obtained fluid velocity vectors from the visualization image using the Particle Imaging Velocimetry (PIV). The results are as follows. 1. Most of coolant flow through a slit of 'column type UIS' arrived the dip plate directly. In the opposite side of a slit, most of coolant flowed toward reactor vessel wall before it arrived the dip plate. 2. The PIV was useful to measure the flow field in the reactor vessel. The obtained velocity field was consistent with the flow visualization result. 3. The jet through the UIS slit was dependent on the UIS geometry. There is a possibility to control the jet by the UIS geometry. (author)

  11. 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.

  12. Imaging of systemic vasculitis in childhood

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, Magdy [The Hospital for Sick Children, Department of Medical Imaging, Toronto, ON (Canada); Cairo University, Department of Medical Imaging, Cairo (Egypt); Laxer, Ronald; Yeung, Rae [The Hospital for Sick Children, Department of Rheumatology, Toronto, ON (Canada); Manson, David; Doria, Andrea S. [The Hospital for Sick Children, Department of Medical Imaging, Toronto, ON (Canada)

    2015-08-15

    The term ''systemic vasculitis'' encompasses a diverse set of diseases linked by the presence of blood-vessel inflammation that are often associated with critical complications. These diseases are uncommon in childhood and are frequently subjected to a delayed diagnosis. Although the diagnosis and treatment may be similar for adult and childhood systemic vasculitides, the prevalence and classification vary according to the age group under investigation. For example, Kawasaki disease affects children while it is rarely encountered in adults. In 2006, the European League Against Rheumatism (EULAR) and the Pediatric Rheumatology European Society (PReS) proposed a classification system for childhood vasculitis adopting the system devised in the Chapel Hill Consensus Conference in 1993, which categorizes vasculitides according to the predominant size of the involved blood vessels into small, medium and large vessel diseases. Currently, medical imaging has a pivotal role in the diagnosis of vasculitis given recent developments in the imaging of blood vessels. For example, early diagnosis of coronary artery aneurysms, a serious complication of Kawasaki disease, is now possible by magnetic resonance imaging (MRI) of the heart and multidetector computed tomography (MDCT); positron emission tomography/CT (PET/CT) helps to assess active vascular inflammation in Takayasu arteritis. Our review offers a unique approach using the integration of the proposed classification criteria for common systemic childhood vasculitides with their most frequent imaging findings, along with differential diagnoses and an algorithm for diagnosis based on common findings. It should help radiologists and clinicians reach an early diagnosis, therefore facilitating the ultimate goal of proper management of affected children. (orig.)

  13. Imaging of systemic vasculitis in childhood

    International Nuclear Information System (INIS)

    Soliman, Magdy; Laxer, Ronald; Yeung, Rae; Manson, David; Doria, Andrea S.

    2015-01-01

    The term ''systemic vasculitis'' encompasses a diverse set of diseases linked by the presence of blood-vessel inflammation that are often associated with critical complications. These diseases are uncommon in childhood and are frequently subjected to a delayed diagnosis. Although the diagnosis and treatment may be similar for adult and childhood systemic vasculitides, the prevalence and classification vary according to the age group under investigation. For example, Kawasaki disease affects children while it is rarely encountered in adults. In 2006, the European League Against Rheumatism (EULAR) and the Pediatric Rheumatology European Society (PReS) proposed a classification system for childhood vasculitis adopting the system devised in the Chapel Hill Consensus Conference in 1993, which categorizes vasculitides according to the predominant size of the involved blood vessels into small, medium and large vessel diseases. Currently, medical imaging has a pivotal role in the diagnosis of vasculitis given recent developments in the imaging of blood vessels. For example, early diagnosis of coronary artery aneurysms, a serious complication of Kawasaki disease, is now possible by magnetic resonance imaging (MRI) of the heart and multidetector computed tomography (MDCT); positron emission tomography/CT (PET/CT) helps to assess active vascular inflammation in Takayasu arteritis. Our review offers a unique approach using the integration of the proposed classification criteria for common systemic childhood vasculitides with their most frequent imaging findings, along with differential diagnoses and an algorithm for diagnosis based on common findings. It should help radiologists and clinicians reach an early diagnosis, therefore facilitating the ultimate goal of proper management of affected children. (orig.)

  14. Effect of a novel motion correction algorithm (SSF) on the image quality of coronary CTA with intermediate heart rates: Segment-based and vessel-based analyses

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qianwen, E-mail: qianwen18@126.com; Li, Pengyu, E-mail: lipyu818@gmail.com; Su, Zhuangzhi, E-mail: suzhuangzhi@xwh.ccmu.edu.cn; Yao, Xinyu, E-mail: 314985151@qq.com; Wang, Yan, E-mail: wy19851121@126.com; Wang, Chen, E-mail: fskwangchen@gmail.com; Du, Xiangying, E-mail: duxying_xw@163.com; Li, Kuncheng, E-mail: kuncheng.li@gmail.com

    2014-11-15

    Highlights: • SSF provided better image quality than single-sector and bi-sector reconstruction among the intermediate heart rates (65–75 bpm). • Evidence for the application of prospective ECG-triggered coronary CTA with SSF onto an expanded heart rate range. • Information about the inconsistent effectiveness of SSF among the segments of coronary artery. - Abstract: Purpose: To evaluate the effect of SnapShot Freeze (SSF) reconstruction at an intermediate heart-rate (HR) range (65–75 bpm) and compare this method with single-sector reconstruction and bi-sector reconstruction on segmental and vessel bases in retrospective coronary computed tomography angiography (CCTA). Materials and methods: Retrospective electrocardiogram-gated CCTA was performed on 37 consecutive patients with HR between 65 and 75 bpm using a 64-row CT scanner. Retrospective single-sector reconstruction, bi-sector reconstruction, and SSF were performed for each patient. Multi-phase single-sector reconstruction was performed to select the optimal phase. SSF and bi-sector images were also reconstructed at the optimal phase. The images were interpreted in an intent-to-diagnose fashion by two experienced readers using a 5-point scale, with 3 points as diagnostically acceptable. Image quality among the three reconstruction groups were compared on per-patient, per-vessel, and per-segment bases. Results: The average HR of the enrolled patients was 69.4 ± 2.7 bpm. A total of 111 vessels and 481 coronary segments were assessed. SSF provided significantly higher interpretability of the coronary segments than bi-sector reconstructions. The qualified and excellent rates of SSF (97.9% and 82.3%) were significantly higher than those of single-sector (92.9% and 66.3%) and bi-sector (90.9% and 64.7%) reconstructions. The image quality score (IQS) using SSF was also significantly higher than those of single-sector and bi-sector reconstructions both on per-patient and per-vessel bases. On per

  15. Cerebral MR imaging in vasculitis

    International Nuclear Information System (INIS)

    Ott, D.; Geissler, A.; Peter, H.H.

    1990-01-01

    This paper evaluates the diagnostic sensitivity and specificity of MR imaging for the detection of cerebral involvement in vasculitis. Seventy-six patient with proved systematic vasculitis and two with isolated cerebral vasculitis were examined. Half of them had central nervous system symptoms. T2-weighted sequences were performed at 2 T in most cases. All but two symptomatic and one-third of the asymptomatic patients showed pathologic changes in the white matter. The distribution and shape of lesions depend on the caliber of the involved vessel. In small-vessel vasculitis, the distribution was mostly subcortical, the average size was 0.5--10 mm, and lesions were predominantly round

  16. What is cerebral small vessel disease?

    International Nuclear Information System (INIS)

    Onodera, Osamu

    2011-01-01

    An accumulating amount of evidence suggests that the white matter hyperintensities on T 2 weighted brain magnetic resonance imaging predict an increased risk of dementia and gait disturbance. This state has been proposed as cerebral small vessel disease, including leukoaraiosis, Binswanger's disease, lacunar stroke and cerebral microbleeds. However, the concept of cerebral small vessel disease is still obscure. To understand the cerebral small vessel disease, the precise structure and function of cerebral small vessels must be clarified. Cerebral small vessels include several different arteries which have different anatomical structures and functions. Important functions of the cerebral small vessels are blood-brain barrier and perivasucular drainage of interstitial fluid from the brain parenchyma. Cerebral capillaries and glial endfeet, take an important role for these functions. However, the previous pathological investigations on cerebral small vessels have focused on larger arteries than capillaries. Therefore little is known about the pathology of capillaries in small vessel disease. The recent discoveries of genes which cause the cerebral small vessel disease indicate that the cerebral small vessel diseases are caused by a distinct molecular mechanism. One of the pathological findings in hereditary cerebral small vessel disease is the loss of smooth muscle cells, which is an also well-recognized finding in sporadic cerebral small vessel disease. Since pericytes have similar character with the smooth muscle cells, the pericytes should be investigated in these disorders. In addition, the loss of smooth muscle cells may result in dysfunction of drainage of interstitial fluid from capillaries. The precise correlation between the loss of smooth muscle cells and white matter disease is still unknown. However, the function that is specific to cerebral small vessel may be associated with the pathogenesis of cerebral small vessel disease. (author)

  17. Angiographic optical coherence tomography imaging of hemangiomas and port wine birthmarks.

    Science.gov (United States)

    Waibel, Jill S; Holmes, Jon; Rudnick, Ashley; Woods, Daniel; Kelly, Kristen M

    2018-03-22

    A current therapeutic challenge of vascular lesions is that they do not always respond effectively to laser treatment. Information on targeted vessels could potentially be used to guide laser treatments. Optical coherence tomography (OCT) is a useful tool for the non-invasive imaging of tissues, including skin hemangiomas and port wine birthmarks. Dynamic OCT is able to rapidly characterize cutaneous blood vessels. The primary goal of this study was to demonstrate the ability of bedside OCT to image (i) overall vessel pattern; (ii) individual vessel morphology, diameter and depth; and (iii) total vessel density as a function of depth in infantile hemangiomas and port wine birthmarks (PWB). This IRB approved, observational clinical trial was performed among healthy volunteers ages 3 months-73 years old. All patients presented for laser treatment of either infantile hemangiomas or PWB with skin types ranging from Fitzpatrick I-V. OCT imaging of 49 hemangioma and PWB scans were performed pre- and post-treatment. The diameter and depth of the blood vessels making up the vascular lesions were measured. In addition, normal skin was scanned for comparison. Five datasets for infantile hemangiomas and five for PWB that were without motion artifacts were analyzed. Scanned lesions exhibited variable and highly heterogeneous blood vessel patterns with vessel diameters ranging from 20 to 160 μm, suggesting that the laser treatment with single pulse durations may not be optimal. The largest blood vessel diameter observed (160 μm) may not be adequately treated by commonly used pulsed dye laser pulse durations. OCT allowed rapid, non-invasive characterization of the diameter and depth of blood vessels in individual vascular lesions. Imaged lesions consisted of a heterogeneous population of vessel sizes, morphologies, and depth. Future studies could utilize this information to assist development of individualized treatment protocols in an effort to improve vascular birthmark

  18. Analysis of size effect applicable to evaluation of fracture toughness of base metal for PWR vessel

    International Nuclear Information System (INIS)

    Benhamou, C.; Joly, P.; Andrieu, A.; Parrot, A.; Vidard, S.

    2015-01-01

    The objective of the present paper is to review the specimen size effect (also called crack front length effect) on Fracture Toughness of PWR Reactor Pressure Vessel Steel base metal. The analysis of the reality and amplitude of this effect is conducted in a first step on a database (the so-called GKSS database) including fracture toughness test results on a single representative material using specimens of different thicknesses, tested in the same temperature range. A realistic analytical form for describing the size effect observed in this data set is thus derived from statistical analyses and proposed for engineering application. In a second step, this size effect formulation is then applied to a large number of fracture toughness data, obtained in Irradiation Surveillance Programs, and also to the numerous data used for the definition of the ASME (and RCC-M) fracture toughness reference curves. This analysis allows normalizing all the available fracture toughness data with a single specimen width of 100 mm and defining the fracture toughness reference curve as the lower bound of this normalized set of data points. It is thus demonstrated that the fracture toughness reference curve is associated with a reference crack length of 100 mm, and can be used in RPV integrity analyses for other crack front length in association with the crack front length correction formula defined in the first step. (authors)

  19. Variations in the size of focal nodular hyperplasia on magnetic resonance imaging.

    Science.gov (United States)

    Ramírez-Fuentes, C; Martí-Bonmatí, L; Torregrosa, A; Del Val, A; Martínez, C

    2013-01-01

    To evaluate the changes in the size of focal nodular hyperplasia (FNH) during long-term magnetic resonance imaging (MRI) follow-up. We reviewed 44 FNHs in 30 patients studied with MRI with at least two MRI studies at least 12 months apart. We measured the largest diameter of the lesion (inmm) in contrast-enhanced axial images and calculated the percentage of variation as the difference between the maximum diameter in the follow-up and the maximum diameter in the initial study. We defined significant variation in size as variation greater than 20%. We also analyzed predisposing hormonal factors. The mean interval between the two imaging studies was 35±2 months (range: 12-94). Most lesions (80%) remained stable during follow-up. Only 9 of the 44 lesions (20%) showed a significant variation in diameter: 7 (16%) decreased in size and 2 (4%) increased, with variations that reached the double of the initial size. The change in size was not related to pregnancy, menopause, or the use of birth control pills or corticoids. Changes in the size of FNHs during follow-up are relatively common and should not lead to a change in the diagnosis. These variations in size seem to be independent of hormonal factors that are considered to predispose. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.

  20. Inner and outer coronary vessel wall segmentation from CCTA using an active contour model with machine learning-based 3D voxel context-aware image force

    Science.gov (United States)

    Sivalingam, Udhayaraj; Wels, Michael; Rempfler, Markus; Grosskopf, Stefan; Suehling, Michael; Menze, Bjoern H.

    2016-03-01

    In this paper, we present a fully automated approach to coronary vessel segmentation, which involves calcification or soft plaque delineation in addition to accurate lumen delineation, from 3D Cardiac Computed Tomography Angiography data. Adequately virtualizing the coronary lumen plays a crucial role for simulating blood ow by means of fluid dynamics while additionally identifying the outer vessel wall in the case of arteriosclerosis is a prerequisite for further plaque compartment analysis. Our method is a hybrid approach complementing Active Contour Model-based segmentation with an external image force that relies on a Random Forest Regression model generated off-line. The regression model provides a strong estimate of the distance to the true vessel surface for every surface candidate point taking into account 3D wavelet-encoded contextual image features, which are aligned with the current surface hypothesis. The associated external image force is integrated in the objective function of the active contour model, such that the overall segmentation approach benefits from the advantages associated with snakes and from the ones associated with machine learning-based regression alike. This yields an integrated approach achieving competitive results on a publicly available benchmark data collection (Rotterdam segmentation challenge).

  1. Evaluation of the embolic effect of polyvinyl alcohol foam particles according to particle size on the cerebral artery of a cat, focusing on T2 weighted MR images and pathologic study after 24 hours

    International Nuclear Information System (INIS)

    Park, Man Soo; Woo, Don Hee; Chung, Haingsub R.; Kang Gil Hyun; Lee, Sang Youl; Ryu, Dae Sik; Lee, Yong Chul

    2000-01-01

    This study was designed to determine the embolic effect of PVA particles of various sizes on the cerebral artery of a cat and to determine the appropriate particle size for embolization. A total of 21 cats were divided into three groups according to the PVA particle size injected: group I (n=3D7), embolized with 45-150μm PVA; group II (n=3D7), with 150-250μm PVA; and group III (n=3D7), with 350-500μm PVA. PVA particles were slowly injected into the left common carotid artery of each cat, and T2-weighted coronal MR images were obtained 24 hours after injection. During histologic examination of brain sections we analyzed the size, number of occluded vessels, and the ischemic changes caused by the particles. On T2 weighted images, areas of high signal intensity (infarction) were observed in four of the seven cats (57%) in group I and in two of the seven (29%) II. High signal intensity was not found in group III. The mean percentage of areas of high signal intensity was 11.86 ± 1.37% in group I and 5.18 ± 1.77% in group II (P less than 0.05). During histologic examination, occlusion of the distal branches of the anterior cerebral (ACA) and/or the middle cerebral arteries (MCA) by PVA particles was observed in all seven cats (100%) in group I, and in four of the seven cats (57%) in group II, No group III cat showed occlusion of the distal branches of the ACA and/or MCA. The mean caliber of occluded vessels was 175μm in Group I and 258μm in Group II. The mean number of occluded vessels seen on all slide sections was 14 in Group I and 5 in Group II. Small PVA particles has a greater cerebral embolic effect than did those which were medium or large. For the induction of embolic infarction in cat brain, PVA particles 45-150μm in size are appropriate. (author)

  2. LumenRECON Guidewire: Pilot Study of a Novel, Nonimaging Technology for Accurate Vessel Sizing and Delivery of Therapy in Femoropopliteal Disease.

    Science.gov (United States)

    Nair, Pradeep K; Carr, Jeffrey G; Bigelow, Brian; Bhatt, Deepak L; Berwick, Zachary C; Adams, George

    2018-01-01

    Proper vessel sizing during endovascular interventions is crucial to avoid adverse procedural and clinical outcomes. LumenRECON (LR) is a novel, nonimaging, 0.035-inch wire-based technology that uses the physics-based principle of Ohm's law to provide a simple, real-time luminal size while also providing a platform for therapy delivery. This study evaluated the accuracy, reliability, and safety of the LR system in patients presenting for a femoropopliteal artery intervention. This multicenter, prospective pilot study of 24 patients presenting for peripheral intervention compared LR measurements of femoropopliteal artery size to angiographic visual estimation, duplex ultrasound, quantitative angiography, and intravascular ultrasound. The primary effectiveness and safety end point was comparison against core laboratory adjudicated intravascular ultrasound values and major adverse events, respectively. Additional preclinical studies were also performed in vitro and in vivo in swine to determine the accuracy of the LR guidewire system. No intra- or postprocedure device-related adverse events occurred. A balloon or stent was successfully delivered in 12 patients (50%) over the LR wire. Differences in repeatability between successive LR measurements was 2.5±0.40% ( R 2 =0.96) with no significant bias. Differences in measurements of LR to other modalities were 0.5±1.7%, 5.0±1.8%, -1.5±2.0%, and 6.8±3.4% for intravascular ultrasound core laboratory, quantitative angiography, angiographic, and duplex ultrasound, respectively. This study demonstrates that through a physics-based principle, LR provides a real-time, safe, reproducible, and accurate vessel size of the femoropopliteal artery during intervention and can additionally serve as a conduit for therapy delivery over its wire-based platform. © 2018 American Heart Association, Inc.

  3. Civacuve analysis software for mis machine examination of pressurized water reactor vessels

    International Nuclear Information System (INIS)

    Dubois, Ph.; Gagnor, A.

    2001-01-01

    The product software CIVACUVE is used by INTERCONTROLE for the analysis of UT examinations, for detection, performed by the In-Service Inspection Machine (MIS) of the vessels of nuclear power plants. This software is based on an adaptation of an algorithm of SEGMENTATION (CEA CEREM), which is applied prior to any analysis. It is equipped with tools adapted to industrial use. It allows to: - perform image analysis thanks to advanced graphic tools (Zooms, True Bscan, 'contour' selection...), - backup of all data in a database (complete and transparent backup of all informations used and obtained during the different analysis operations), - connect PC to the Database (export of Reports and even of segmented points), - issue Examination Reports, Operating Condition Sheets, Sizing curves... - and last, perform a graphic and numerical comparison between different inspections of the same vessel. Used in Belgium and France on different kind of reactor vessels, CIVACUVE has allowed to show that the principle of SEGMENTATION can be adapted to detection exams. The use of CIVACUVE generates a important time gain as well as the betterment of quality in analysis. Wide data opening toward PC's allows a real flexibility with regard to client's requirements and preoccupations

  4. Problems in Pressure Vessel Design and Manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Hellstroem, O [Uddeholms AB, Degerfors (Sweden); Nilson, Ragnar [AB Atomenergi, Nykoeping (Sweden)

    1963-05-15

    The general desire by the power reactor process makers to increase power rating and their efforts to involve more advanced thermal behaviour and fuel handling facilities within the reactor vessels are accompanied by an increase in both pressure vessel dimensions and various difficulties in giving practical solutions of design materials and fabrication problems. In any section of this report it is emphasized that difficulties and problems already met with will meet again in the future vessels but then in modified forms and in many cases more pertinent than before. As for the increase in geometrical size it can be postulated that with use of better materials and adjusted fabrication methods the size problems can be taken proper care of. It seems likely that vessels of sufficient large diameter and height for the largest power output, which is judged as interesting in the next ten year period, can be built without developing totally new site fabrication technique. It is, however, supposed that such a fabrication technique will be feasible though at higher specific costs for the same quality requirements as obtained in shop fabrication. By the postulated use of more efficient vessel material with principally the same good features of easy fabrication in different stages such as preparation, welding, heat treatment etc as ordinary or slightly modified carbon steels the increase in wall thickness might be kept low. There exists, however, a development work to be done for low-alloy steels to prove their justified use in large reactor pressure vessels.

  5. Problems in Pressure Vessel Design and Manufacture

    International Nuclear Information System (INIS)

    Hellstroem, O.; Nilson, Ragnar

    1963-05-01

    The general desire by the power reactor process makers to increase power rating and their efforts to involve more advanced thermal behaviour and fuel handling facilities within the reactor vessels are accompanied by an increase in both pressure vessel dimensions and various difficulties in giving practical solutions of design materials and fabrication problems. In any section of this report it is emphasized that difficulties and problems already met with will meet again in the future vessels but then in modified forms and in many cases more pertinent than before. As for the increase in geometrical size it can be postulated that with use of better materials and adjusted fabrication methods the size problems can be taken proper care of. It seems likely that vessels of sufficient large diameter and height for the largest power output, which is judged as interesting in the next ten year period, can be built without developing totally new site fabrication technique. It is, however, supposed that such a fabrication technique will be feasible though at higher specific costs for the same quality requirements as obtained in shop fabrication. By the postulated use of more efficient vessel material with principally the same good features of easy fabrication in different stages such as preparation, welding, heat treatment etc as ordinary or slightly modified carbon steels the increase in wall thickness might be kept low. There exists, however, a development work to be done for low-alloy steels to prove their justified use in large reactor pressure vessels

  6. [Imaging anatomy of cranial nerves].

    Science.gov (United States)

    Hermier, M; Leal, P R L; Salaris, S F; Froment, J-C; Sindou, M

    2009-04-01

    Knowledge of the anatomy of the cranial nerves is mandatory for optimal radiological exploration and interpretation of the images in normal and pathological conditions. CT is the method of choice for the study of the skull base and its foramina. MRI explores the cranial nerves and their vascular relationships precisely. Because of their small size, it is essential to obtain images with high spatial resolution. The MRI sequences optimize contrast between nerves and surrounding structures (cerebrospinal fluid, fat, bone structures and vessels). This chapter discusses the radiological anatomy of the cranial nerves.

  7. Role of radiation embrittlement in reactor vessel integrity assessment

    International Nuclear Information System (INIS)

    Marston, T.U.; Chexal, V.K.; Wyckoff, M.

    1982-01-01

    Reactor vessel integrity calculations are complex. The effect of radiation embrittlement on vessel material properties is a very important aspect of any vessel integrity evaluation. The importance of realistic (based on surveillance capsule results) rather than conservative estimates of the material properties (based on regulatory curves) cannot be overestimated. It is also important to make realistic thermal hydraulic and system operations assumptions. In addition, use of actual flaw sizes from in-service inspections (versus hypothetical flaw size selection) will promote realism. Important research results exist that need to be incorporated into the regulatory process. The authors believe results from current research and development efforts will demonstrate that, with reasonable assumptions and best estimate calculations, the safety of even the older reactor vessels with high copper content welds can be assured over their design lifetimes without the need for major fixes. The utilities, through EPRI and the vendors, have dedicated a significant effort to solving the pressurized thermal shock problem

  8. Radiation embrittlement of PWR vessel supports

    International Nuclear Information System (INIS)

    Cheverton, R.D.; Robinson, G.C.; Pennell, W.E.; Nanstad, R.K.

    1989-01-01

    Several studies pertaining to radiation damage of PWR vessel supports were conducted between 1978 and 1987. During this period, apparently there was no reason to believe that low-temperature (<100 degree C) MTR embrittlement data were not appropriate for evaluating embrittlement of PWR vessel supports. However, late in 1986, data from the High Flux Isotope Reactor (HFIR) vessel surveillance program indicated that the embrittlement rates of the several HFIR vessel materials (A212-B, A350-LF3, A105-II) were substantially greater than anticipated on the basis of MTR data. Further evaluation of the HFIR data suggested that a fluence-rate effect was responsible for the apparent discrepancy, and shortly thereafter it became apparent that this rate effect was applicable to the evaluation of LWR vessel supports. As a result, the Nuclear Regulatory Commission (NRC) requested that the Oak Ridge National Laboratory (ORNL) evaluate the impact of the apparent embrittlement rate effect on the integrity of light-water-reactor (LWR) vessel supports. The purpose of the study was to provide an indication of whether the integrity of reactor vessel supports is likely to be challenged by radiation-induced embrittlement. The scope of the evaluation included correlation of the HFIR data for application to the evaluation of LWR vessel supports; a survey and cursory evaluation of all US LWR vessel support designs, selection of two plants for specific-plant evaluation, and a specific-plant evaluation of both plants to determine critical flaw sizes for their vessel supports. 19 refs., 8 figs., 2 tabs

  9. An Approach for Selection of Flow Regime and Models for Conservative Evaluation of a Vessel Integrity Monitoring System for Water-Cooled Vacuum Vessels

    International Nuclear Information System (INIS)

    Pointer, W. David; Ruggles, Arthur E.

    2003-01-01

    Thin-walled vacuum containment vessels cooled by circulating water jackets are often utilized in research and industrial applications where isolation of equipment or experiments from the influences of the surrounding environment is desirable. The development of leaks in these vessels can result in costly downtime for the facility. A Vessel Integrity Monitoring System (VIMS) is developed to detect leak formation and estimate the size of the leak to allow evaluation of the risk associated with continued operation. A wide range of leak configurations and fluid flow phenomena are considered in the evaluation of the rate at which a tracer gas dissolved in the cooling jacket water is transported into the vacuum vessel. A methodology is presented that uses basic fluid flow models and careful evaluation of their ranges of applicability to provide a conservative estimate of the transport rates for the tracer gas and hence the time required for the VIMS to detect a leak of a given size

  10. Improvement of retinal blood vessel detection by spur removal and Gaussian matched filtering compensation

    Science.gov (United States)

    Xiao, Di; Vignarajan, Janardhan; An, Dong; Tay-Kearney, Mei-Ling; Kanagasingam, Yogi

    2016-03-01

    Retinal photography is a non-invasive and well-accepted clinical diagnosis of ocular diseases. Qualitative and quantitative assessment of retinal images is crucial in ocular diseases related clinical application. In this paper, we proposed approaches for improving the quality of blood vessel detection based on our initial blood vessel detection methods. A blood vessel spur pruning method has been developed for removing the blood vessel spurs both on vessel medial lines and binary vessel masks, which are caused by artifacts and side-effect of Gaussian matched vessel enhancement. A Gaussian matched filtering compensation method has been developed for removing incorrect vessel branches in the areas of low illumination. The proposed approaches were applied and tested on the color fundus images from one publicly available database and our diabetic retinopathy screening dataset. A preliminary result has demonstrated the robustness and good performance of the proposed approaches and their potential application for improving retinal blood vessel detection.

  11. A Morphological Hessian Based Approach for Retinal Blood Vessels Segmentation and Denoising Using Region Based Otsu Thresholding.

    Directory of Open Access Journals (Sweden)

    Khan BahadarKhan

    Full Text Available Diabetic Retinopathy (DR harm retinal blood vessels in the eye causing visual deficiency. The appearance and structure of blood vessels in retinal images play an essential part in the diagnoses of an eye sicknesses. We proposed a less computational unsupervised automated technique with promising results for detection of retinal vasculature by using morphological hessian based approach and region based Otsu thresholding. Contrast Limited Adaptive Histogram Equalization (CLAHE and morphological filters have been used for enhancement and to remove low frequency noise or geometrical objects, respectively. The hessian matrix and eigenvalues approach used has been in a modified form at two different scales to extract wide and thin vessel enhanced images separately. Otsu thresholding has been further applied in a novel way to classify vessel and non-vessel pixels from both enhanced images. Finally, postprocessing steps has been used to eliminate the unwanted region/segment, non-vessel pixels, disease abnormalities and noise, to obtain a final segmented image. The proposed technique has been analyzed on the openly accessible DRIVE (Digital Retinal Images for Vessel Extraction and STARE (STructured Analysis of the REtina databases along with the ground truth data that has been precisely marked by the experts.

  12. Human dental pulp stem cells and gingival fibroblasts seeded into silk fibroin scaffolds have the same ability in attracting vessels

    Directory of Open Access Journals (Sweden)

    Anna eWoloszyk

    2016-04-01

    Full Text Available Neovascularization is one of the most important processes during tissue repair and regeneration. Current healing approaches based on the use of biomaterials combined with stem cells in critical-size bone defects fail due to the insufficient implant vascularization and integration into the host tissues. Therefore, here we studied the attraction, ingrowth, and distribution of blood vessels from the chicken embryo chorioallantoic membrane into implanted silk fibroin scaffolds seeded with either human dental pulp stem cells or human gingival fibroblasts. Perfusion capacity was evaluated by non-invasive in vivo Magnetic Resonance Imaging while the number and density of blood vessels were measured by histomorphometry. Our results demonstrate that human dental pulp stem cells and gingival fibroblasts possess equal abilities in attracting vessels within silk fibroin scaffolds. Additionally, the prolonged in vitro pre-incubation period of these two cell populations favors the homogeneous distribution of vessels within silk fibroin scaffolds, which further improves implant survival and guarantees successful healing and regeneration.

  13. Autonomous bed-sediment imaging-systems for revealing temporal variability of grain size

    Science.gov (United States)

    Buscombe, Daniel; Rubin, David M.; Lacy, Jessica R.; Storlazzi, Curt D.; Hatcher, Gerald; Chezar, Henry; Wyland, Robert; Sherwood, Christopher R.

    2014-01-01

    We describe a remotely operated video microscope system, designed to provide high-resolution images of seabed sediments. Two versions were developed, which differ in how they raise the camera from the seabed. The first used hydraulics and the second used the energy associated with wave orbital motion. Images were analyzed using automated frequency-domain methods, which following a rigorous partially supervised quality control procedure, yielded estimates to within 20% of the true size as determined by on-screen manual measurements of grains. Long-term grain-size variability at a sandy inner shelf site offshore of Santa Cruz, California, USA, was investigated using the hydraulic system. Eighteen months of high frequency (min to h), high-resolution (μm) images were collected, and grain size distributions compiled. The data constitutes the longest known high-frequency record of seabed-grain size at this sample frequency, at any location. Short-term grain-size variability of sand in an energetic surf zone at Praa Sands, Cornwall, UK was investigated using the ‘wave-powered’ system. The data are the first high-frequency record of grain size at a single location of a highly mobile and evolving bed in a natural surf zone. Using this technology, it is now possible to measure bed-sediment-grain size at a time-scale comparable with flow conditions. Results suggest models of sediment transport at sandy, wave-dominated, nearshore locations should allow for substantial changes in grain-size distribution over time-scales as short as a few hours.

  14. Automatic determination of the size of elliptical nanoparticles from AFM images

    International Nuclear Information System (INIS)

    Sedlář, Jiří; Zitová, Barbara; Kopeček, Jaromír; Flusser, Jan; Todorciuc, Tatiana; Kratochvílová, Irena

    2013-01-01

    The objective of this work was to develop an accurate method for automatic determination of the size of elliptical nanoparticles from atomic force microscopy (AFM) images that would yield results consistent with results of manual measurements by experts. The proposed method was applied on phenylpyridyldiketopyrrolopyrrole (PPDP), a granular organic material with a wide scale of application and highly sensitive particle-size properties. A PPDP layer consists of similarly sized elliptical particles (c. 100 nm × 50 nm) and its properties can be estimated from the average length and width of the particles. The developed method is based on segmentation of salient particles by the watershed transform and approximation of their shapes by ellipses computed by image moments; it estimates the lengths and widths of the particles by the major and minor axes, respectively, of the corresponding ellipses. Its results proved to be consistent with results of manual measurements by a trained expert. The comparison showed that the developed method could be used in practice for precise automatic measurement of PPDP particles in AFM images

  15. A simple algorithm for measuring particle size distributions on an uneven background from TEM images

    DEFF Research Database (Denmark)

    Gontard, Lionel Cervera; Ozkaya, Dogan; Dunin-Borkowski, Rafal E.

    2011-01-01

    Nanoparticles have a wide range of applications in science and technology. Their sizes are often measured using transmission electron microscopy (TEM) or X-ray diffraction. Here, we describe a simple computer algorithm for measuring particle size distributions from TEM images in the presence of a...... application to images of heterogeneous catalysts is presented.......Nanoparticles have a wide range of applications in science and technology. Their sizes are often measured using transmission electron microscopy (TEM) or X-ray diffraction. Here, we describe a simple computer algorithm for measuring particle size distributions from TEM images in the presence...

  16. U.S. and French approaches to reactor pressure vessel integrity

    International Nuclear Information System (INIS)

    Griesbach, T.J.; Buchalet, C.; Server, W.L.

    1990-01-01

    The effects of radiation embrittlement on the reactor pressure vessel must be considered for continued safe operation of nuclear power plants. The consequences of radiation embrittlement require detailed assessments of the margins of safety against brittle fracture of the vessel. The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code and U.S. Regulations often use conservative approaches for these assessments which can eventually lead to severe operational hardships for some plants. Taking a look at alternative integrity approaches, such as those demonstrated in France, could ultimately result in improved ASME Code and Regulatory limits. The French studies have shown the significance of performing proper in- service inspections to reliably show that no defects larger than a predetermined size (or class) exist in the inspected region of a vessel. The predetermined size is based upon previous studies on the types of manufacturing defects which can potentially exist in French vessels. Enhanced linear elastic and elastic-plastic fracture mechanics methodologies can be applied to evaluate such defects to assure that brittle fracture will not occur

  17. An approach to localize the retinal blood vessels using bit planes and centerline detection.

    Science.gov (United States)

    Fraz, M M; Barman, S A; Remagnino, P; Hoppe, A; Basit, A; Uyyanonvara, B; Rudnicka, A R; Owen, C G

    2012-11-01

    The change in morphology, diameter, branching pattern or tortuosity of retinal blood vessels is an important indicator of various clinical disorders of the eye and the body. This paper reports an automated method for segmentation of blood vessels in retinal images. A unique combination of techniques for vessel centerlines detection and morphological bit plane slicing is presented to extract the blood vessel tree from the retinal images. The centerlines are extracted by using the first order derivative of a Gaussian filter in four orientations and then evaluation of derivative signs and average derivative values is performed. Mathematical morphology has emerged as a proficient technique for quantifying the blood vessels in the retina. The shape and orientation map of blood vessels is obtained by applying a multidirectional morphological top-hat operator with a linear structuring element followed by bit plane slicing of the vessel enhanced grayscale image. The centerlines are combined with these maps to obtain the segmented vessel tree. The methodology is tested on three publicly available databases DRIVE, STARE and MESSIDOR. The results demonstrate that the performance of the proposed algorithm is comparable with state of the art techniques in terms of accuracy, sensitivity and specificity. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  18. Pressure vessel integrity and weld inspection procedure

    International Nuclear Information System (INIS)

    Solomon, K.A.; Okrent, D.; Kastenberg, W.E.

    1975-01-01

    The primary objective of this paper is to develop a simple methodology which, when coupled with existing observations on pressure vessel behavior, provides an inter-relation between pressure vessel integrity, and the parameters of the in-service inspection program, including inspection sample size, frequency and efficiency. A modified Markov process is employed and a computer code was written to obtain numerical results. The Markov process mathematically describes the following physical events. In a nuclear reactor pressure vessel weld, some defects may exist prior to the zeroth inspection (i.e., prior to vessel operation). During the zeroth inspection and repair processes, some of these defects are removed. During the first cycle of vessel operation, the existing defects may grow and some new defects may be generated. Those defects that are found at the first (and succeeding) inspection interval and warrant repair, are repaired. The above process continues through several operating cycles to the end of vessel life. During any inspection, only a portion of the welds may be inspected, and with less than perfect efficiency

  19. In-vessel maintenance remote manipulator system

    International Nuclear Information System (INIS)

    Jimenez, E.

    1978-01-01

    The radiation environment within the Tokamak Fusion Test Reactor (TFTR) vacuum vessel necessitates the development of a Remote Manipulator System (RMS) to perform required periodic inspection and maintenance tasks. The RMS must be able to perform dexterous operations and handle loads that exceed human capabilities. The limited size of the access ports on the TFTR vacuum vessel and the performance profile, defined by the various handling requirements, present unique design constraints. The design approach and formulation of a RMS configuration which satisfies TFTR requirements is presented herein

  20. Improvement of retinal blood vessel detection using morphological component analysis.

    Science.gov (United States)

    Imani, Elaheh; Javidi, Malihe; Pourreza, Hamid-Reza

    2015-03-01

    Detection and quantitative measurement of variations in the retinal blood vessels can help diagnose several diseases including diabetic retinopathy. Intrinsic characteristics of abnormal retinal images make blood vessel detection difficult. The major problem with traditional vessel segmentation algorithms is producing false positive vessels in the presence of diabetic retinopathy lesions. To overcome this problem, a novel scheme for extracting retinal blood vessels based on morphological component analysis (MCA) algorithm is presented in this paper. MCA was developed based on sparse representation of signals. This algorithm assumes that each signal is a linear combination of several morphologically distinct components. In the proposed method, the MCA algorithm with appropriate transforms is adopted to separate vessels and lesions from each other. Afterwards, the Morlet Wavelet Transform is applied to enhance the retinal vessels. The final vessel map is obtained by adaptive thresholding. The performance of the proposed method is measured on the publicly available DRIVE and STARE datasets and compared with several state-of-the-art methods. An accuracy of 0.9523 and 0.9590 has been respectively achieved on the DRIVE and STARE datasets, which are not only greater than most methods, but are also superior to the second human observer's performance. The results show that the proposed method can achieve improved detection in abnormal retinal images and decrease false positive vessels in pathological regions compared to other methods. Also, the robustness of the method in the presence of noise is shown via experimental result. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  1. The effect of nanoparticle size on theranostic systems: the optimal particle size for imaging is not necessarily optimal for drug delivery

    Science.gov (United States)

    Dreifuss, Tamar; Betzer, Oshra; Barnoy, Eran; Motiei, Menachem; Popovtzer, Rachela

    2018-02-01

    Theranostics is an emerging field, defined as combination of therapeutic and diagnostic capabilities in the same material. Nanoparticles are considered as an efficient platform for theranostics, particularly in cancer treatment, as they offer substantial advantages over both common imaging contrast agents and chemotherapeutic drugs. However, the development of theranostic nanoplatforms raises an important question: Is the optimal particle for imaging also optimal for therapy? Are the specific parameters required for maximal drug delivery, similar to those required for imaging applications? Herein, we examined this issue by investigating the effect of nanoparticle size on tumor uptake and imaging. Anti-epidermal growth factor receptor (EGFR)-conjugated gold nanoparticles (GNPs) in different sizes (diameter range: 20-120 nm) were injected to tumor bearing mice and their uptake by tumors was measured, as well as their tumor visualization capabilities as tumor-targeted CT contrast agent. Interestingly, the results showed that different particles led to highest tumor uptake or highest contrast enhancement, meaning that the optimal particle size for drug delivery is not necessarily optimal for tumor imaging. These results have important implications on the design of theranostic nanoplatforms.

  2. High spatial resolution whole-body MR angiography featuring parallel imaging: initial experience

    International Nuclear Information System (INIS)

    Quick, H.H.; Vogt, F.M.; Madewald, S.; Herborn, C.U.; Bosk, S.; Goehde, S.; Debatin, J.F.; Ladd, M.E.

    2004-01-01

    Materials and methods: whole-body multi-station MRA was performed with a rolling table platform (AngioSURF) on 5 volunteers in two imaging series: 1) standard imaging protocol, 2) modified high-resolution protocol employing PAT using the generalized autocalibrating partially parallel acquisitions (GRAPPA) algorithm with an acceleration factor of 3. For an intra-individual comparison of the two MR examinations, the arterial vasculature was divided into 30 segments. Signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were calculated for all 30 arterial segments of each subject. Vessel segment depiction was qualitatively assessed applying a 5-point scale to each of the segments. Image reconstruction times were recorded for the standard as well as the PAT protocol. Results: compared to the standard protocol, PAT allowed for increased spatial resolution through a 3-fold reduction in mean voxel size for each of the 5 stations. Mean SNR and CNR values over all specified vessel segments decreased by a factor of 1.58 and 1.56, respectively. Despite the reduced SNR and CNR, the depiction of all specified vessel segments increased in PAT images, reflecting the increased spatial resolution. Qualitative comparison of standard and PAT images showed an increase in vessel segment conspicuity with more detailed depiction of intramuscular arterial branches in all volunteers. The time for image data reconstruction of all 5 stations was significantly increased from about 10 minutes to 40 minutes when using the PAT acquisition. (orig.) [de

  3. A modified Seeded Region Growing algorithm for vessel segmentation in breast MRI images for investigating the nature of potential lesions

    Science.gov (United States)

    Glotsos, D.; Vassiou, K.; Kostopoulos, S.; Lavdas, El; Kalatzis, I.; Asvestas, P.; Arvanitis, D. L.; Fezoulidis, I. V.; Cavouras, D.

    2014-03-01

    The role of Magnetic Resonance Imaging (MRI) as an alternative protocol for screening of breast cancer has been intensively investigated during the past decade. Preliminary research results have indicated that gadolinium-agent administrative MRI scans may reveal the nature of breast lesions by analyzing the contrast-agent's uptake time. In this study, we attempt to deduce the same conclusion, however, from a different perspective by investigating, using image processing, the vascular network of the breast at two different time intervals following the administration of gadolinium. Twenty cases obtained from a 3.0-T MRI system (SIGNA HDx; GE Healthcare) were included in the study. A new modification of the Seeded Region Growing (SRG) algorithm was used to segment vessels from surrounding background. Delineated vessels were investigated by means of their topology, morphology and texture. Results have shown that it is possible to estimate the nature of the lesions with approximately 94.4% accuracy, thus, it may be claimed that the breast vascular network does encodes useful, patterned, information, which can be used for characterizing breast lesions.

  4. Interferometric laser imaging for in-flight cloud droplet sizing

    International Nuclear Information System (INIS)

    Dunker, Christina; Roloff, Christoph; Grassmann, Arne

    2016-01-01

    A non-intrusive particle sizing method with a high spatial distribution is used to estimate cloud droplet spectra during flight test campaigns. The interferometric laser imaging for droplet sizing (ILIDS) method derives particle diameters of transparent spheres by evaluating the out-of-focus image patterns. This sizing approach requires a polarized monochromatic light source, a camera including an objective lens with a slit aperture, a synchronization unit and a processing tool for data evaluation. These components are adapted to a flight test environment to enable the microphysical investigation of different cloud genera. The present work addresses the design and specifications of ILIDS system, flight test preparation and selected results obtained in the lower and middle troposphere. The research platform was a Dornier Do228-101 commuter aircraft at the DLR Flight Operation Center in Braunschweig. It was equipped with the required instrumentation including a high-energy laser as the light source. A comprehensive data set of around 71 800 ILIDS images was acquired over the course of five flights. The data evaluation of the characteristic ILIDS fringe patterns relies, among other things, on a relationship between the fringe spacing and the diameter of the particle. The simplest way to extract this information from a pattern is by fringe counting, which is not viable for such an extensive number of data. A brief contrasting comparison of evaluation methods based on frequency analysis by means of fast Fourier transform and on correlation methods such as minimum quadratic difference is used to encompass the limits and accuracy of the ILIDS method for such applications. (paper)

  5. IMPACTS OF PATCH SIZE AND LANDSCAPE HETEROGENEITY ON THEMATIC IMAGE CLASSIFICATION ACCURACY

    Science.gov (United States)

    Impacts of Patch Size and Landscape Heterogeneity on Thematic Image Classification Accuracy. Currently, most thematic accuracy assessments of classified remotely sensed images oily account for errors between the various classes employed, at particular pixels of interest, thu...

  6. Automatic detection of micro-aneurysms in retinal images based on curvelet transform and morphological operations

    Science.gov (United States)

    Mohammad Alipour, Shirin Hajeb; Rabbani, Hossein

    2013-09-01

    Diabetic retinopathy (DR) is one of the major complications of diabetes that changes the blood vessels of the retina and distorts patient vision that finally in high stages can lead to blindness. Micro-aneurysms (MAs) are one of the first pathologies associated with DR. The number and the location of MAs are very important in grading of DR. Early diagnosis of micro-aneurysms (MAs) can reduce the incidence of blindness. As MAs are tiny area of blood protruding from vessels in the retina and their size is about 25 to 100 microns, automatic detection of these tiny lesions is still challenging. MAs occurring in the macula can lead to visual loss. Also the position of a lesion such as MAs relative to the macula is a useful feature for analysis and classification of different stages of DR. Because MAs are more distinguishable in fundus fluorescin angiography (FFA) compared to color fundus images, we introduce a new method based on curvelet transform and morphological operations for MAs detection in FFA images. As vessels and MAs are the bright parts of FFA image, firstly extracted vessels by curvelet transform are removed from image. Then morphological operations are applied on resulted image for detecting MAs.

  7. NOVEL PRERETINAL HAIR PIN-LIKE VESSEL IN RETINAL ASTROCYTIC HAMARTOMA WITH VITREOUS HEMORRHAGE.

    Science.gov (United States)

    Soeta, Megumi; Arai, Yusuke; Takahashi, Hidenori; Fujino, Yujiro; Tanabe, Tatsuro; Inoue, Yuji; Kawashima, Hidetoshi

    2018-01-01

    To report a case of retinal astrocytic hamartoma with vitreous hemorrhage and a hair pin-like vessel adhering to a posterior vitreous membrane. A 33-year-old man with a retinal astrocytic hamartoma presented with vitreous hemorrhage 5 times. Multimodal imaging, including fundus photography, fluorescein angiography, optical coherence tomography, and B-mode ultrasonography. Multimodal imaging demonstrated a novel hair pin-like vessel that adhered to the posterior vitreous membrane. Some cases of retinal astrocytic hamartoma with vitreous hemorrhage may be related to structure abnormalities of tumor vessels.

  8. Low temperature radiation embrittlement for reactor vessel steels

    International Nuclear Information System (INIS)

    Ginding, I.A.; Chirkina, L.A.

    1978-01-01

    General conceptions of cold brittleness of bcc metals are in a review. Considered are experimental data and theoretical representations about the effect of irradiation conditions, chemical composition, phase and structural constitutions, grain size, mechanical and thermomechanical treatments on low-temperature irradiation embrittlement of reactor vessel steels. Presented are the methods for increasing radiation stability of metals (carbon and Cr-Mo steels) used in manufacturing reactor vessels

  9. Novel Computerized Method for Measurement of Retinal Vessel Diameters

    Directory of Open Access Journals (Sweden)

    Hichem Guedri

    2017-03-01

    Full Text Available Several clinical studies reveal the relationship between alterations in the topologies of the human retinal blood vessel, the outcrop and the disease evolution, such as diabetic retinopathy, hypertensive retinopathy, and macular degeneration. Indeed, the detection of these vascular changes always has gaps. In addition, the manual steps are slow, which may be subjected to a bias of the perceiver. However, we can overcome these troubles using computer algorithms that are quicker and more accurate. This paper presents and investigates a novel method for measuring the blood vessel diameter in the retinal image. The proposed method is based on a thresholding segmentation and thinning step, followed by the characteristic point determination step by the Douglas-Peucker algorithm. Thereafter, it uses the active contours to detect vessel contour. Finally, Heron’s Formula is applied to assure the calculation of vessel diameter. The obtained results for six sample images showed that the proposed method generated less errors compared to other techniques, which confirms the high performance of the proposed method.

  10. Correcting for particle size effects on plasma actuator particle image velocimetry measurements

    Science.gov (United States)

    Masati, A.; Sedwick, R. J.

    2018-01-01

    Particle image velocimetry (PIV) is often used to characterize plasma actuator flow, but particle charging effects are rarely taken into account. A parametric study was conducted to determine the effects of particle size on the velocity results of plasma actuator PIV experiments. Results showed that smaller particles more closely match air flow velocities than larger particles. The measurement uncertainty was quantified by deconvolving the particle image diameter from the correlation diameter. The true air velocity was calculated by linearly extrapolating to the zero-size particle diameter.

  11. Impact of focal spot size on radiologic image quality: A visual grading analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gorham, Sinead [Diagnostic Imaging, Biological Imaging Research, UCD School of Medicine and Medical Science, Health Science, Belfield, UCD, Dublin 4 (Ireland); Brennan, Patrick C., E-mail: patrick.brennan@ucd.i [Diagnostic Imaging, Biological Imaging Research, UCD School of Medicine and Medical Science, Health Science, Belfield, UCD, Dublin 4 (Ireland)

    2010-11-15

    Fine and broad focal spot sizes are available on general X-ray tubes. Excessive use of fine focus can impact on tube life and whilst it is established that fine focal spot size reduces geometric unsharpness, the extent of this benefit on clinical image quality is unclear. The current cadaver-based work compares images produced with effective focal sizes of 0.8 mm and 1.8 mm. Four projection types were included, lateral ankle, antero-posterior (AP) knee, AP thoracic spine and horizontal beam lateral (HBL) lumbar spine, and a visual grading analysis was used to assess visibility of anatomical criteria. Five clinicians scored each image using a 1-4 scoring scale, a reference image was employed for standardization and a Mann-Whitney U statistical test compared results derived from each focus. Radiation doses were monitored using a dose area product (DAP) meter. Statistical analyses demonstrated no significant differences between images produced at each focus, although a relationship between body part thickness and number of criteria with a higher (non-significant) score for the fine focus compared with the broad focal spot size was demonstrated. Choice of focus had no radiation dose implications. Fine foci X-ray sources are used predominantly for extremity imaging to enhance visualization of fine detail such as trabecular patterns, yet there is no evidence to support this practice. The argument for regular employment of fine foci, particularly for the type of acquisition and display devices used in this study, needs to be revisited.

  12. Alterations of the cerebral cortex in sporadic small vessel disease: A systematic review of in vivo MRI data.

    Science.gov (United States)

    Peres, Roxane; De Guio, François; Chabriat, Hugues; Jouvent, Eric

    2016-04-01

    Cerebral small vessel diseases of the brain are a major determinant of cognitive impairment in the elderly. In small vessel diseases, the most easily identifiable lesions, both at post-mortem evaluation and magnetic resonance imaging, lie in subcortical areas. However, recent results obtained post-mortem, particularly in severe cases, have highlighted the burden of cortex lesions such as microinfarcts and diffuse neuronal loss. The recent development of image post-processing methods allows now assessing in vivo multiple aspects of the cerebral cortex. This systematic review aimed to analyze in vivo magnetic resonance imaging studies evaluating cortex alterations at different stages of small vessel diseases. Studies assessing the relationships between small vessel disease magnetic resonance imaging markers obtained at the subcortical level and cortex estimates were reviewed both in community-dwelling elderly and in patients with symptomatic small vessel diseases. Thereafter, studies analyzing cortex estimates in small vessel disease patients compared with healthy subjects were evaluated. The results support that important cortex alterations develop along the course of small vessel diseases independently of concomitant neurodegenerative processes. Easy detection and quantification of cortex changes in small vessel diseases as well as understanding their underlying mechanisms are challenging tasks for better understanding cognitive decline in small vessel diseases. © The Author(s) 2016.

  13. Superficial vessel reconstruction with a multiview camera system

    Science.gov (United States)

    Marreiros, Filipe M. M.; Rossitti, Sandro; Karlsson, Per M.; Wang, Chunliang; Gustafsson, Torbjörn; Carleberg, Per; Smedby, Örjan

    2016-01-01

    Abstract. We aim at reconstructing superficial vessels of the brain. Ultimately, they will serve to guide the deformation methods to compensate for the brain shift. A pipeline for three-dimensional (3-D) vessel reconstruction using three mono-complementary metal-oxide semiconductor cameras has been developed. Vessel centerlines are manually selected in the images. Using the properties of the Hessian matrix, the centerline points are assigned direction information. For correspondence matching, a combination of methods was used. The process starts with epipolar and spatial coherence constraints (geometrical constraints), followed by relaxation labeling and an iterative filtering where the 3-D points are compared to surfaces obtained using the thin-plate spline with decreasing relaxation parameter. Finally, the points are shifted to their local centroid position. Evaluation in virtual, phantom, and experimental images, including intraoperative data from patient experiments, shows that, with appropriate camera positions, the error estimates (root-mean square error and mean error) are ∼1  mm. PMID:26759814

  14. Automatic detection of blood vessels in retinal images for diabetic retinopathy diagnosis.

    Science.gov (United States)

    Raja, D Siva Sundhara; Vasuki, S

    2015-01-01

    Diabetic retinopathy (DR) is a leading cause of vision loss in diabetic patients. DR is mainly caused due to the damage of retinal blood vessels in the diabetic patients. It is essential to detect and segment the retinal blood vessels for DR detection and diagnosis, which prevents earlier vision loss in diabetic patients. The computer aided automatic detection and segmentation of blood vessels through the elimination of optic disc (OD) region in retina are proposed in this paper. The OD region is segmented using anisotropic diffusion filter and subsequentially the retinal blood vessels are detected using mathematical binary morphological operations. The proposed methodology is tested on two different publicly available datasets and achieved 93.99% sensitivity, 98.37% specificity, 98.08% accuracy in DRIVE dataset and 93.6% sensitivity, 98.96% specificity, and 95.94% accuracy in STARE dataset, respectively.

  15. Effect of a new specimen size on fatigue crack growth behavior in thick-walled pressure vessels

    International Nuclear Information System (INIS)

    Shariati, Mahmoud; Mohammadi, Ehsan; Masoudi Nejad, Reza

    2017-01-01

    Fatigue crack growth in thick-walled pressure vessels is an important factor affecting their fracture. Predicting the path of fatigue crack growth in a pressure vessel is the main issue discussed in fracture mechanics. The objective of this paper is to design a new geometrical specimen in fatigue to define the behavior of semi-elliptical crack growth in thick-walled pressure vessels. In the present work, the importance of the behavior of fatigue crack in test specimen and real conditions in thick-walled pressure vessels is investigated. The results of fatigue loading on the new specimen are compared with the results of fatigue loading in a cylindrical pressure vessel and a standard specimen. Numerical and experimental methods are used to investigate the behavior of fatigue crack growth in the new specimen. For this purpose, a three-dimensional boundary element method is used for fatigue crack growth under stress field. The modified Paris model is used to estimate fatigue crack growth rates. In order to verify the numerical results, fatigue test is carried out on a couple of specimens with a new geometry made of ck45. A comparison between experimental and numerical results has shown good agreement. - Highlights: • This paper provides a new specimen to define the behavior of fatigue crack growth. • We estimate the behavior of fatigue crack growth in specimen and pressure vessel. • A 3D finite element model has been applied to estimate the fatigue life. • We compare the results of fatigue loading for cylindrical vessel and specimens. • Comparison between experimental and numerical results has shown a good agreement.

  16. A scaling law for the local CHF on the external bottom side of a fully submerged reactor vessel

    International Nuclear Information System (INIS)

    Cheung, F.B.; Haddad, K.H.; Liu, Y.C.

    1997-01-01

    A scaling law for estimating the local critical heat flux on the outer surface of a heated hemispherical vessel that is fully submerged in water has been developed from the results of an advanced hydrodynamic CHF model for pool boiling on a downward facing curved heating surface. The scaling law accounts for the effects of the size of the vessel, the level of liquid subcooling, the intrinsic properties of the fluid, and the spatial variation of the local critical heat flux along the heating surface. It is found that for vessels with diameters considerably larger than the characteristic size of the vapor masses, the size effect on the local critical heat flux is limited almost entirely to the effect of subcooling associated with the local liquid head. When the subcooling effect is accounted for separately, the local CHF limit is nearly independent of the vessel size. Based upon the scaling law developed in this work, it is possible to merge, within the experimental uncertainties, all the available local CHF data obtained for various vessel sizes under both saturated and subcooled boiling conditions into a single curve. Applications of the scaling law to commercial-size vessels have been made for various system pressures and water levels above the heated vessel. Over the range of conditions explored in this study, the local CHF limit is found to increase by a factor of two or more from the bottom center to the upper edge of the vessel. Meanwhile, the critical heat flux at a given angular position of the heated vessel is also found to increase appreciably with the system pressure and the water level

  17. Fast retinal vessel detection and measurement using wavelets and edge location refinement.

    Directory of Open Access Journals (Sweden)

    Peter Bankhead

    Full Text Available The relationship between changes in retinal vessel morphology and the onset and progression of diseases such as diabetes, hypertension and retinopathy of prematurity (ROP has been the subject of several large scale clinical studies. However, the difficulty of quantifying changes in retinal vessels in a sufficiently fast, accurate and repeatable manner has restricted the application of the insights gleaned from these studies to clinical practice. This paper presents a novel algorithm for the efficient detection and measurement of retinal vessels, which is general enough that it can be applied to both low and high resolution fundus photographs and fluorescein angiograms upon the adjustment of only a few intuitive parameters. Firstly, we describe the simple vessel segmentation strategy, formulated in the language of wavelets, that is used for fast vessel detection. When validated using a publicly available database of retinal images, this segmentation achieves a true positive rate of 70.27%, false positive rate of 2.83%, and accuracy score of 0.9371. Vessel edges are then more precisely localised using image profiles computed perpendicularly across a spline fit of each detected vessel centreline, so that both local and global changes in vessel diameter can be readily quantified. Using a second image database, we show that the diameters output by our algorithm display good agreement with the manual measurements made by three independent observers. We conclude that the improved speed and generality offered by our algorithm are achieved without sacrificing accuracy. The algorithm is implemented in MATLAB along with a graphical user interface, and we have made the source code freely available.

  18. Fuzzy-Based Segmentation for Variable Font-Sized Text Extraction from Images/Videos

    Directory of Open Access Journals (Sweden)

    Samabia Tehsin

    2014-01-01

    Full Text Available Textual information embedded in multimedia can provide a vital tool for indexing and retrieval. A lot of work is done in the field of text localization and detection because of its very fundamental importance. One of the biggest challenges of text detection is to deal with variation in font sizes and image resolution. This problem gets elevated due to the undersegmentation or oversegmentation of the regions in an image. The paper addresses this problem by proposing a solution using novel fuzzy-based method. This paper advocates postprocessing segmentation method that can solve the problem of variation in text sizes and image resolution. The methodology is tested on ICDAR 2011 Robust Reading Challenge dataset which amply proves the strength of the recommended method.

  19. Rotation invariant eigenvessels and auto-context for retinal vessel detection

    Science.gov (United States)

    Montuoro, Alessio; Simader, Christian; Langs, Georg; Schmidt-Erfurth, Ursula

    2015-03-01

    Retinal vessels are one of the few anatomical landmarks that are clearly visible in various imaging modalities of the eye. As they are also relatively invariant to disease progression, retinal vessel segmentation allows cross-modal and temporal registration enabling exact diagnosing for various eye diseases like diabetic retinopathy, hypertensive retinopathy or age-related macular degeneration (AMD). Due to the clinical significance of retinal vessels many different approaches for segmentation have been published in the literature. In contrast to other segmentation approaches our method is not specifically tailored to the task of retinal vessel segmentation. Instead we utilize a more general image classification approach and show that this can achieve comparable results. In the proposed method we utilize the concepts of eigenfaces and auto-context. Eigenfaces have been described quite extensively in the literature and their performance is well known. They are however quite sensitive to translation and rotation. The former was addressed by computing the eigenvessels in local image windows of different scales, the latter by estimating and correcting the local orientation. Auto-context aims to incorporate automatically generated context information into the training phase of classification approaches. It has been shown to improve the performance of spinal cord segmentation4 and 3D brain image segmentation. The proposed method achieves an area under the receiver operating characteristic (ROC) curve of Az = 0.941 on the DRIVE data set, being comparable to current state-of-the-art approaches.

  20. Three-Dimensional Digital Image Correlation of a Composite Overwrapped Pressure Vessel During Hydrostatic Pressure Tests

    Science.gov (United States)

    Revilock, Duane M., Jr.; Thesken, John C.; Schmidt, Timothy E.

    2007-01-01

    Ambient temperature hydrostatic pressurization tests were conducted on a composite overwrapped pressure vessel (COPV) to understand the fiber stresses in COPV components. Two three-dimensional digital image correlation systems with high speed cameras were used in the evaluation to provide full field displacement and strain data for each pressurization test. A few of the key findings will be discussed including how the principal strains provided better insight into system behavior than traditional gauges, a high localized strain that was measured where gages were not present and the challenges of measuring curved surfaces with the use of a 1.25 in. thick layered polycarbonate panel that protected the cameras.

  1. Localization and proliferation of lymphatic vessels in the tympanic membrane in normal state and regeneration

    International Nuclear Information System (INIS)

    Miyashita, Takenori; Burford, James L.; Hong, Young-Kwon; Gevorgyan, Haykanush; Lam, Lisa; Mori, Nozomu; Peti-Peterdi, Janos

    2013-01-01

    Highlights: •We newly developed the whole-mount imaging method of the tympanic membrane. •Lymphatic vessel loops were localized around the malleus handle and annulus tympanicus. •In regeneration, abundant lymphatic vessels were observed in the pars tensa. •Site-specific lymphatic vessels may play an important role in the tympanic membrane. -- Abstract: We clarified the localization of lymphatic vessels in the tympanic membrane and proliferation of lymphatic vessels during regeneration after perforation of the tympanic membrane by using whole-mount imaging of the tympanic membrane of Prox1 GFP mice. In the pars tensa, lymphatic vessel loops surrounded the malleus handle and annulus tympanicus. Apart from these locations, lymphatic vessel loops were not observed in the pars tensa in the normal tympanic membrane. Lymphatic vessel loops surrounding the malleus handle were connected to the lymphatic vessel loops in the pars flaccida and around the tensor tympani muscle. Many lymphatic vessel loops were detected in the pars flaccida. After perforation of the tympanic membrane, abundant lymphatic regeneration was observed in the pars tensa, and these regenerated lymphatic vessels extended from the lymphatic vessels surrounding the malleus at day 7. These results suggest that site-specific lymphatic vessels play an important role in the tympanic membrane

  2. Vessel encoded arterial spin labeling with cerebral perfusion: preliminary study

    International Nuclear Information System (INIS)

    Wu Bing; Xiao Jiangxi; Xie Cheng; Wang Xiaoying; Jiang Xuexiang; Wong, E.C.; Wang Jing; Guo Jia; Zhang Beiru; Zhang Jue; Fang Jing

    2008-01-01

    Objective: To evaluate a noninvasive vessel encoded imaging for selective mapping of the flow territories of the left and fight internal carotid arteries and vertebral-basilar arteries. Methods: Seven volunteers [(33.5 ± 4.1) years; 3 men, 4 women] and 6 patients [(55.2 ± 3.2) years; 2 men, 4 women] were given written informed consent approved by the institutional review board before participating in the study. A pseudo-continuous tagging pulse train is modified to encode all vessels of interest. The selectivity of this method was demonstrated. Regional perfusion imaging was developed on the same arterial spin labeling sequence. Perfusion-weighted images of the selectively labeled cerebral arteries were obtained by subtraction of the labeled from control images. The CBF values of hemisphere, white matter, and gray matter of volunteers were calculated. The vessel territories on patients were compared with DSA. The low perfusion areas were compared with high signal areas on T 2 -FLAIR. Results: High SNR maps of left carotid, right carotid, and basilar territories were generated in 8 minutes of scan time. Cerebral blood flow values measured with regional perfusion imaging in the complete hemisphere (32.6 ± 4.3) ml·min -1 · 100 g -1 , white matter (10.8 ± 0.9) ml·min -1 ·100 g -1 , and gray matter (55.6±2.9) ml·min -1 · 100 g -1 were in agreement with data in the literature. Vessel encoded imaging in patients had a good agreement with DSA. The low perfusion areas were larger than high signal areas on T 2 -FLAIR. Conclusion: We present a new method capable of evaluating both quantitatively and qualitatively the individual brain- feeding arteries in vivo. (authors)

  3. High frequency transducer for vessel imaging based on lead-free Mn-doped (K0.44Na0.56)NbO3 single crystal

    Science.gov (United States)

    Ma, Jinpeng; Xue, Saidong; Zhao, Xiangyong; Wang, Feifei; Tang, Yanxue; Duan, Zhihua; Wang, Tao; Shi, Wangzhou; Yue, Qingwen; Zhou, Huifang; Luo, Haosu; Fang, Bijun

    2017-08-01

    We report a high frequency ultrasonic transducer up to 50 MHz for vessel imaging based on a lead-free (K0.44Na0.56)NbO3-0.5 mol. % Mn (Mn-KNN) single crystal, which has a high electromechanical coupling coefficient kt of 0.64 and a large thickness frequency constant Nt of 3210 kHz . mm. The Krimholtz, Leedom, and Mattaei (KLM) equivalent circuit model was utilized to simulate and optimize the pulse-echo response combined with PiezoCAD software. Theoretically, a high -6 dB bandwidth of 74.94% was obtained at a center frequency of 50.47 MHz and optimized matching conditions. The experimental results showed a center frequency of 51.8 MHz with a -6 dB bandwidth of 70.2%. The excellent global performance makes this lead-free single-crystal transducer quite potential in an environmentally friendly vessel imaging transducer.

  4. MEMS-based handheld fourier domain Doppler optical coherence tomography for intraoperative microvascular anastomosis imaging.

    Directory of Open Access Journals (Sweden)

    Yong Huang

    Full Text Available To demonstrate the feasibility of a miniature handheld optical coherence tomography (OCT imager for real time intraoperative vascular patency evaluation in the setting of super-microsurgical vessel anastomosis.A novel handheld imager Fourier domain Doppler optical coherence tomography based on a 1.3-µm central wavelength swept source for extravascular imaging was developed. The imager was minimized through the adoption of a 2.4-mm diameter microelectromechanical systems (MEMS scanning mirror, additionally a 12.7-mm diameter lens system was designed and combined with the MEMS mirror to achieve a small form factor that optimize functionality as a handheld extravascular OCT imager. To evaluate in-vivo applicability, super-microsurgical vessel anastomosis was performed in a mouse femoral vessel cut and repair model employing conventional interrupted suture technique as well as a novel non-suture cuff technique. Vascular anastomosis patency after clinically successful repair was evaluated using the novel handheld OCT imager.With an adjustable lateral image field of view up to 1.5 mm by 1.5 mm, high-resolution simultaneous structural and flow imaging of the blood vessels were successfully acquired for BALB/C mouse after orthotopic hind limb transplantation using a non-suture cuff technique and BALB/C mouse after femoral artery anastomosis using a suture technique. We experimentally quantify the axial and lateral resolution of the OCT to be 12.6 µm in air and 17.5 µm respectively. The OCT has a sensitivity of 84 dB and sensitivity roll-off of 5.7 dB/mm over an imaging range of 5 mm. Imaging with a frame rate of 36 Hz for an image size of 1000(lateral×512(axial pixels using a 50,000 A-lines per second swept source was achieved. Quantitative vessel lumen patency, lumen narrowing and thrombosis analysis were performed based on acquired structure and Doppler images.A miniature handheld OCT imager that can be used for intraoperative evaluation of

  5. Crack propagation on spherical pressure vessels

    International Nuclear Information System (INIS)

    Lebey, J.; Roche, R.

    1975-01-01

    The risk presented by a crack on a pressure vessel built with a ductile steel cannot be well evaluated by simple application of the rules of Linear Elastic Fracture Mechanics, which only apply to brittle materials. Tests were carried out on spherical vessels of three different scales built with the same steel. Cracks of different length were machined through the vessel wall. From the results obtained, crack initiation stress (beginning of stable propagation) and instable propagation stress may be plotted against the lengths of these cracks. For small and medium size, subject to ductile fracture, the resulting curves are identical, and may be used for ductile fracture prediction. Brittle rupture was observed on larger vessels and crack propagation occurred at lower stress level. Preceedings curves are not usable for fracture analysis. Ultimate pressure can be computed with a good accuracy by using equivalent energy toughness, Ksub(1cd), characteristic of the metal plates. Satisfactory measurements have been obtained on thin samples. The risks of brittle fracture may then judged by comparing Ksub(1cd) with the calculated K 1 value, in which corrections for vessel shape are taken into account. It is thus possible to establish the bursting pressure of cracked spherical vessels, with the help of two rules, one for brittle fracture, the other for ductile instability. A practical method is proposed on the basis of the work reported here

  6. Probabilistic atlas based labeling of the cerebral vessel tree

    Science.gov (United States)

    Van de Giessen, Martijn; Janssen, Jasper P.; Brouwer, Patrick A.; Reiber, Johan H. C.; Lelieveldt, Boudewijn P. F.; Dijkstra, Jouke

    2015-03-01

    Preoperative imaging of the cerebral vessel tree is essential for planning therapy on intracranial stenoses and aneurysms. Usually, a magnetic resonance angiography (MRA) or computed tomography angiography (CTA) is acquired from which the cerebral vessel tree is segmented. Accurate analysis is helped by the labeling of the cerebral vessels, but labeling is non-trivial due to anatomical topological variability and missing branches due to acquisition issues. In recent literature, labeling the cerebral vasculature around the Circle of Willis has mainly been approached as a graph-based problem. The most successful method, however, requires the definition of all possible permutations of missing vessels, which limits application to subsets of the tree and ignores spatial information about the vessel locations. This research aims to perform labeling using probabilistic atlases that model spatial vessel and label likelihoods. A cerebral vessel tree is aligned to a probabilistic atlas and subsequently each vessel is labeled by computing the maximum label likelihood per segment from label-specific atlases. The proposed method was validated on 25 segmented cerebral vessel trees. Labeling accuracies were close to 100% for large vessels, but dropped to 50-60% for small vessels that were only present in less than 50% of the set. With this work we showed that using solely spatial information of the vessel labels, vessel segments from stable vessels (>50% presence) were reliably classified. This spatial information will form the basis for a future labeling strategy with a very loose topological model.

  7. Imaging and size measurement of nanoparticles in aqueous medium by use of atomic force microscopy.

    Science.gov (United States)

    Takechi-Haraya, Yuki; Goda, Yukihiro; Sakai-Kato, Kumiko

    2018-02-01

    Size control of nanoparticles in nanotechnology-based drug products is crucial for their successful development, since the in vivo pharmacokinetics of nanoparticles are size-dependent. In this study, we evaluated the use of atomic force microscopy (AFM) for imaging and size measurement of nanoparticles in aqueous medium. The height sizes of rigid polystyrene nanoparticles and soft liposomes were measured by AFM and were compared with the hydrodynamic sizes measured by dynamic light scattering (DLS). The lipid compositions of the studied liposomes were similar to those of commercial products. AFM proved to be a viable method for obtaining images of both polystyrene nanoparticles and liposomes in aqueous medium. For the polystyrene nanoparticles, the average height size observed by AFM was similar to the average number-weighted diameter obtained by DLS, indicating the usefulness of AFM for measuring the sizes of nanoparticles in aqueous medium. For the liposomes, the height sizes obtained by AFM differed depending upon the procedures of immobilizing the liposomes onto a solid substrate. In addition, the resultant average height sizes of the liposomes were smaller than those obtained by DLS. This knowledge will help the correct use of AFM as a powerful tool for imaging and size measurement of nanotechnology-based drug products for clinical use.

  8. The Effect of the Degree of Luminal Contrast-Enhancement on CT Measurement of Plaque Size: A Comparison with T1-weighted Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Choi, Byoung Wook; Hur, Jin; Lee, Hye Jeong; Kim, Young Jin; Choe, Kyu Ok; Kim, Tae Hoon

    2010-01-01

    We studied early and delayed contrast-enhanced CT to determine the effects of the degree of luminal enhancement on the measurement of plaque size compared to T1-weighted MRI. T1-weighted MRI and a two-phase contrast-enhanced CT was performed in 5 New Zealand white rabbits with atherosclerosis. Early-phase images were acquired during an expected peak enhancement period of the lumen; delayed-phase images were acquired 240 sec after administration of the contrast media. Anteroposterior and lateral luminal diameters (APD, LD), luminal area (LA), total vessel area (TVA), and plaque area (PA) of the aorta were measured on MRI and CT, respectively and compared to each other. A total of 78 slices of the aorta were analyzed. PA, measured on T1-weighted MR images, was significantly greater than PA for both early-phase and delayed-phase CT (p 2 (p 2 (p 2 (p = 0.159) for MRI vs. early-phase CT, MRI vs. delayed-phase CT, and early-phase CT vs. delayed-phase CT, respectively. Different luminal densities by contrast enhancement do not affect the CT measurement of plaque area for the detection of obstructive coronary artery disease

  9. The IBAS image analyser and its use in particle size measurement

    International Nuclear Information System (INIS)

    Snelling, K.W.

    1984-10-01

    The Kontron image analyser (IBAS) is used at Winfrith primarily for size analysis of aerosol particles. The system incorporates two computers, IBAS 1 for system communication and control, and IBAS 2 containing the main image memories. The first is accessed via a keyboard or digitiser tablet, and output can be displayed on a monitor or in printed form. The contents of the image memories are displayed on a colour monitor. Automatic image analysis is described, with typical applications, including the measurement of monodisperse particles, sodium fire aerosols, reactor crud particles and cadmium-silver aerosol particles. (U.K.)

  10. Heavy-Section Steel Technology Program intermediate-scale pressure vessel tests

    International Nuclear Information System (INIS)

    Bryan, R.H.; Merkle, J.G.; Smith, G.C.; Whitman, G.D.

    1977-01-01

    The tests of intermediate-size vessels with sharp flaws permitted the comparison of experimentally observed behavior with analytical predictions of the behavior of flawed pressure vessels. Fracture strains estimated by linear elastic fracture mechanics (LEFM) were accurate in the cases in which the flaws resided in regions of high transverse restraint and the fracture toughness was sufficiently low for unstable fracture to occur prior to yielding through the vessel wall. When both of these conditions were not present, unstable fracture did occur, always preceded by stable crack growth; and the cylinders with flaws initially less than halfway through the wall attained gross yield prior to burst. Predictions of failure pressure of the vessels with flawed nozzles, based upon LEFM estimates of failure strain, were very conservative. LEFM calculations of critical load were based upon small-specimen fracture toughness test data. Whenever gross yielding preceded failure, the actual strains achieved were considerably greater than the estimated strains at failure based on LEFM. In such cases the strength of the vessel may be no longer dependent upon plane-strain fracture toughness but upon the capacity of the cracked section to carry the imposed load stably in the plastic range. Stable crack growth, which has not been predictable quantitatively, is an important factor in elastic-plastic analysis of strength. The ability of the flawed vessels to attain gross yield in unflawed sections has important qualitative implications on pressure vessel safety margins. The gross yield condition occurs in light-water-reactor pressure vessels at about 2 x design pressure. The intermediate vessel tests that demonstrated a capacity for exceeding this load confirm that the presumed margin of safety is not diminished by the presence of flaws of substantial size, provided that material properties are adequate

  11. Three-dimensional image reconstruction from stereo DSA

    International Nuclear Information System (INIS)

    Sakamoto, Kiyoshi; Kotoura, Noriko; Umehara, Takayoshi; Yamada, Eiji; Inaba, Tomohiro; Itou, Hiroshi

    1999-01-01

    The technique of interventional radiology has spread rapidly in recent years, and three-dimensional information from blood vessel images is being sought to enhance examinations. Stereo digital subtraction angiography (DSA) and rotational DSA were developed for that purpose. However, it is difficult with stereo DSA to observe the image pair during examination and to obtain positional information on blood vessels. Further, the exposure dose is increased in rotational DSA when many mask images need to be collected, and the patient is required to hold his or her breath for a long duration. We therefore devised a technique to construct three-dimensional blood vessel images by employing geometrical information extracted from stereo DSA images using the right and left images. We used a judgment method based on the correlation coefficient, although we had to extract an equal blood vessel from the right and left images to determine the three-dimensional coordinates of the blood vessel. The reconstructed three-dimensional blood vessels were projected from various angles, again by using a virtual focus, and new images were created. These image groups were displayed as rotational images by the animation display function incorporated in the DSA device. This system can observe blood vessel images of the same phase at a free angle, although the image quality is inferior to that of rotational DSA. In addition, because collection of the mask images is reduced, exposure dose can be decreased. Further, the system offers enhanced safety because no mechanical movement of the imaging system is involved. (author)

  12. Ultrasonically enhanced fractionation of milk fat in a litre-scale prototype vessel.

    Science.gov (United States)

    Leong, Thomas; Johansson, Linda; Mawson, Raymond; McArthur, Sally L; Manasseh, Richard; Juliano, Pablo

    2016-01-01

    The ultrasonic fractionation of milk fat in whole milk to fractions with distinct particle size distributions was demonstrated using a stage-based ultrasound-enhanced gravity separation protocol. Firstly, a single stage ultrasound gravity separation was characterised after various sonication durations (5-20 min) with a mass balance, where defined volume partitions were removed across the height of the separation vessel to determine the fat content and size distribution of fat droplets. Subsequent trials using ultrasound-enhanced gravity separation were carried out in three consecutive stages. Each stage consisted of 5 min sonication, with single and dual transducer configurations at 1 MHz and 2 MHz, followed by aliquot collection for particle size characterisation of the formed layers located at the bottom and top of the vessel. After each sonication stage, gentle removal of the separated fat layer located at the top was performed. Results indicated that ultrasound promoted the formation of a gradient of vertically increasing fat concentration and particle size across the height of the separation vessel, which became more pronounced with extended sonication time. Ultrasound-enhanced fractionation provided fat enriched fractions located at the top of the vessel of up to 13 ± 1% (w/v) with larger globules present in the particle size distributions. In contrast, semi-skim milk fractions located at the bottom of the vessel as low as 1.2 ± 0.01% (w/v) could be produced, containing proportionally smaller sized fat globules. Particle size differentiation was enhanced at higher ultrasound energy input (up to 347 W/L). In particular, dual transducer after three-stage operation at maximum energy input provided highest mean particle size differentiation with up to 0.9 μm reduction in the semi-skim fractions. Higher frequency ultrasound at 2 MHz was more effective in manipulating smaller sized fat globules retained in the later stages of skimming than 1 MHz. While 2 MHz

  13. High-resolution ultrasound imaging and noninvasive optoacoustic monitoring of blood variables in peripheral blood vessels

    Science.gov (United States)

    Petrov, Irene Y.; Petrov, Yuriy; Prough, Donald S.; Esenaliev, Rinat O.

    2011-03-01

    Ultrasound imaging is being widely used in clinics to obtain diagnostic information non-invasively and in real time. A high-resolution ultrasound imaging platform, Vevo (VisualSonics, Inc.) provides in vivo, real-time images with exceptional resolution (up to 30 microns) using high-frequency transducers (up to 80 MHz). Recently, we built optoacoustic systems for probing radial artery and peripheral veins that can be used for noninvasive monitoring of total hemoglobin concentration, oxyhemoglobin saturation, and concentration of important endogenous and exogenous chromophores (such as ICG). In this work we used the high-resolution ultrasound imaging system Vevo 770 for visualization of the radial artery and peripheral veins and acquired corresponding optoacoustic signals from them using the optoacoustic systems. Analysis of the optoacoustic data with a specially developed algorithm allowed for measurement of blood oxygenation in the blood vessels as well as for continuous, real-time monitoring of arterial and venous blood oxygenation. Our results indicate that: 1) the optoacoustic technique (unlike pure optical approaches and other noninvasive techniques) is capable of accurate peripheral venous oxygenation measurement; and 2) peripheral venous oxygenation is dependent on skin temperature and local hemodynamics. Moreover, we performed for the first time (to the best of our knowledge) a comparative study of optoacoustic arterial oximetry and a standard pulse oximeter in humans and demonstrated superior performance of the optoacoustic arterial oximeter, in particular at low blood flow.

  14. AN EFFICIENT TECHNIQUE FOR RETINAL VESSEL SEGMENTATION AND DENOISING USING MODIFIED ISODATA AND CLAHE

    Directory of Open Access Journals (Sweden)

    Khan Bahadar Khan

    2016-11-01

    Full Text Available Retinal damage caused due to complications of diabetes is known as Diabetic Retinopathy (DR. In this case, the vision is obscured due to the damage of retinal tinny blood vessels of the retina. These tinny blood vessels may cause leakage which affect the vision and can lead to complete blindness. Identification of these new retinal vessels and their structure is essential for analysis of DR. Automatic blood vessels segmentation plays a significant role to assist subsequent automatic methodologies that aid to such analysis. In literature most of the people have used computationally hungry a strong preprocessing steps followed by a simple thresholding and post processing, But in our proposed technique we utilize an arrangement of  light pre-processing which consists of Contrast Limited Adaptive Histogram Equalization (CLAHE for contrast enhancement, a difference image of green channel from its Gaussian blur filtered image to remove local noise or geometrical object, Modified Iterative Self Organizing Data Analysis Technique (MISODATA for segmentation of vessel and non-vessel pixels based on global and local thresholding, and a strong  post processing using region properties (area, eccentricity to eliminate the unwanted region/segment, non-vessel pixels and noise that never been used to reject misclassified foreground pixels. The strategy is tested on the publically accessible DRIVE (Digital Retinal Images for Vessel Extraction and STARE (STructured Analysis of the REtina databases. The performance of proposed technique is assessed comprehensively and the acquired accuracy, robustness, low complexity and high efficiency and very less computational time that make the method an efficient tool for automatic retinal image analysis. Proposed technique perform well as compared to the existing strategies on the online available databases in term of accuracy, sensitivity, specificity, false positive rate, true positive rate and area under receiver

  15. Multi-atlas pancreas segmentation: Atlas selection based on vessel structure.

    Science.gov (United States)

    Karasawa, Ken'ichi; Oda, Masahiro; Kitasaka, Takayuki; Misawa, Kazunari; Fujiwara, Michitaka; Chu, Chengwen; Zheng, Guoyan; Rueckert, Daniel; Mori, Kensaku

    2017-07-01

    Automated organ segmentation from medical images is an indispensable component for clinical applications such as computer-aided diagnosis (CAD) and computer-assisted surgery (CAS). We utilize a multi-atlas segmentation scheme, which has recently been used in different approaches in the literature to achieve more accurate and robust segmentation of anatomical structures in computed tomography (CT) volume data. Among abdominal organs, the pancreas has large inter-patient variability in its position, size and shape. Moreover, the CT intensity of the pancreas closely resembles adjacent tissues, rendering its segmentation a challenging task. Due to this, conventional intensity-based atlas selection for pancreas segmentation often fails to select atlases that are similar in pancreas position and shape to those of the unlabeled target volume. In this paper, we propose a new atlas selection strategy based on vessel structure around the pancreatic tissue and demonstrate its application to a multi-atlas pancreas segmentation. Our method utilizes vessel structure around the pancreas to select atlases with high pancreatic resemblance to the unlabeled volume. Also, we investigate two types of applications of the vessel structure information to the atlas selection. Our segmentations were evaluated on 150 abdominal contrast-enhanced CT volumes. The experimental results showed that our approach can segment the pancreas with an average Jaccard index of 66.3% and an average Dice overlap coefficient of 78.5%. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Efficient Vessel Tracking  with Accuracy Guarantees

    DEFF Research Database (Denmark)

    Redoutey, Martin; Scotti, Eric; Jensen, Christian Søndergaard

    2008-01-01

    Safety and security are top concerns in maritime navigation, particularly as maritime traffic continues to grow and as crew sizes are reduced. The Automatic Identification System (AIS) plays a key role in regard to these concerns. This system, whose objective is in part to identify and locate ves...... accuracies at lower communication costs. The techniques employ movement predictions that are shared between vessels and the VTS. Empirical studies with a prototype implementation and real vessel data demonstrate that the techniques are capable of significantly improving the AIS....

  17. Registration of angiographic image on real-time fluoroscopic image for image-guided percutaneous coronary intervention.

    Science.gov (United States)

    Kim, Dongkue; Park, Sangsoo; Jeong, Myung Ho; Ryu, Jeha

    2018-02-01

    In percutaneous coronary intervention (PCI), cardiologists must study two different X-ray image sources: a fluoroscopic image and an angiogram. Manipulating a guidewire while alternately monitoring the two separate images on separate screens requires a deep understanding of the anatomy of coronary vessels and substantial training. We propose 2D/2D spatiotemporal image registration of the two images in a single image in order to provide cardiologists with enhanced visual guidance in PCI. The proposed 2D/2D spatiotemporal registration method uses a cross-correlation of two ECG series in each image to temporally synchronize two separate images and register an angiographic image onto the fluoroscopic image. A guidewire centerline is then extracted from the fluoroscopic image in real time, and the alignment of the centerline with vessel outlines of the chosen angiographic image is optimized using the iterative closest point algorithm for spatial registration. A proof-of-concept evaluation with a phantom coronary vessel model with engineering students showed an error reduction rate greater than 74% on wrong insertion to nontarget branches compared to the non-registration method and more than 47% reduction in the task completion time in performing guidewire manipulation for very difficult tasks. Evaluation with a small number of experienced doctors shows a potentially significant reduction in both task completion time and error rate for difficult tasks. The total registration time with real procedure X-ray (angiographic and fluoroscopic) images takes [Formula: see text] 60 ms, which is within the fluoroscopic image acquisition rate of 15 Hz. By providing cardiologists with better visual guidance in PCI, the proposed spatiotemporal image registration method is shown to be useful in advancing the guidewire to the coronary vessel branches, especially those difficult to insert into.

  18. Lymphatic vessel density and function in experimental bladder cancer

    International Nuclear Information System (INIS)

    Saban, Marcia R; Wu, Xue-Ru; Saban, Ricardo; Towner, Rheal; Smith, Nataliya; Abbott, Andrew; Neeman, Michal; Davis, Carole A; Simpson, Cindy; Maier, Julie; Mémet, Sylvie

    2007-01-01

    The lymphatics form a second circulatory system that drains the extracellular fluid and proteins from the tumor microenvironment, and provides an exclusive environment in which immune cells interact and respond to foreign antigen. Both cancer and inflammation are known to induce lymphangiogenesis. However, little is known about bladder lymphatic vessels and their involvement in cancer formation and progression. A double transgenic mouse model was generated by crossing a bladder cancer-induced transgenic, in which SV40 large T antigen was under the control of uroplakin II promoter, with another transgenic mouse harboring a lacZ reporter gene under the control of an NF-κB-responsive promoter (κB-lacZ) exhibiting constitutive activity of β-galactosidase in lymphatic endothelial cells. In this new mouse model (SV40-lacZ), we examined the lymphatic vessel density (LVD) and function (LVF) during bladder cancer progression. LVD was performed in bladder whole mounts and cross-sections by fluorescent immunohistochemistry (IHC) using LYVE-1 antibody. LVF was assessed by real-time in vivo imaging techniques using a contrast agent (biotin-BSA-Gd-DTPA-Cy5.5; Gd-Cy5.5) suitable for both magnetic resonance imaging (MRI) and near infrared fluorescence (NIRF). In addition, IHC of Cy5.5 was used for time-course analysis of co-localization of Gd-Cy5.5 with LYVE-1-positive lymphatics and CD31-positive blood vessels. SV40-lacZ mice develop bladder cancer and permitted visualization of lymphatics. A significant increase in LVD was found concomitantly with bladder cancer progression. Double labeling of the bladder cross-sections with LYVE-1 and Ki-67 antibodies indicated cancer-induced lymphangiogenesis. MRI detected mouse bladder cancer, as early as 4 months, and permitted to follow tumor sizes during cancer progression. Using Gd-Cy5.5 as a contrast agent for MRI-guided lymphangiography, we determined a possible reduction of lymphatic flow within the tumoral area. In addition, NIRF

  19. Variability of mechanical properties of nuclear pressure vessel steels

    International Nuclear Information System (INIS)

    Petrequin, P.; Soulat, P.

    1980-01-01

    Causes of variability of mechanical properties nuclear pressure vessel steels are reviewed and discussed. The effects of product shape and size, processing history and heat treatment are investigated. Some quantitative informations are given on the scatter of mechanical properties of typical pressure vessel components. The necessity of using recommended or standardized properties for comparing mechanical properties before and after irradiation in pin pointed. (orig.) [de

  20. An automated computerized methodology for the segmentation of in vivo acquired DSA images: application in the New Zealand hindlimb ischemia model

    International Nuclear Information System (INIS)

    Kagadis, G C; Daskalakis, A; Spyridonos, P; Nikiforidis, G C; Diamantopoulos, A; Samaras, N; Katsanos, K; Karnabatidis, D; Siablis, D; Sourgiadaki, E; Cavouras, D

    2009-01-01

    In-vivo dynamic visualization and accurate quantification of vascular networks is a prerequisite of crucial importance in both therapeutic angiogenesis and tumor anti-angiogenesis studies. A user independent computerized tool was developed, for the automated segmentation and quantitative assessment of in-vivo acquired DSA images. Automatic vessel assessment was performed employing the concept of image structural tensor. Initially, vasculature was estimated according to the largest eigenvalue of the structural tensor. The resulted eigenvalue matrix was treated as gray-matrix from which the vessels were gradually segmented and then categorized in three main sub-groups; large, medium and small-size vessels. The histogram percentiles, corresponding to 85%, 65% and 47% of prime eigenvalue gray-matrix were optimally found to give the thresholds T1, T2 and T3 respectively, for extracting vessels of different size. The proposed methodology was tested on a series of DSA images in both normal rabbits (group A) and in rabbits with experimental induced chronic hindlimb ischemia (group B). As a result an automated computerized tool was developed to process images without any user intervention in either experimental or clinical studies. Specifically, a higher total vascular area and length were calculated in group B compared to group A (p=0.0242 and p=0.0322 respectively), which is in accordance to the fact that significantly more collateral arteries are developed during the physiological response to the stimuli of ischemia.

  1. Platform image processing to study the structural properties of retinal vessel

    Directory of Open Access Journals (Sweden)

    Miguel Ángel MERCHÁN

    2013-05-01

    Full Text Available This paper presents a technological platform specialized in assessing retinal vessel caliber and describing the relationship of the results obtained to cardiovascular risk. Retinal circulation is an area of active research by numerous groups, and there is general experimental agreement on the analysis of the patterns of the retinal blood vessels in the normal human retina. The development of automated tools designed to improve performance and decrease interobserver variability, therefore, appears necessary. 

  2. Device of supporting a vacuum plasma vessel

    International Nuclear Information System (INIS)

    Kanoi, Minoru; Hori, Yasuro.

    1980-01-01

    Purpose: To improve the earthquake-resistance of a vacuum plasma vessel by equalizing the natural vibrations of a vibrating system formed by supporting mechanisms of the respective sectors of the vessel. Constitution: The vacuum plasma vessel is constructed of bellows interposed among a plurality of thick sector-like rings and the rings, which are respectively supported by supporting mechanisms. Thus, the vibrating systems are divided into the rings interposed with the bellows, arms as the supporting mechanisms, and posts. The natural vibrations of these vibrating systems are equalized to each other by suitably adjusting the configurations and the sized of the arms and the posts or the weight or the like of the rings. Therefore, the respective rings become vibrated at the natural vibrations equal to each other so as to largely reduce the stresses produced at both ends of the bellows. Accordingly, it can remarkably improve the earthquake-resistance of the entire plasma vessel. (Sekiya, K.)

  3. Optical Coherence Tomography Angiography Vessel Density in Healthy, Glaucoma Suspect, and Glaucoma Eyes

    Science.gov (United States)

    Yarmohammadi, Adeleh; Zangwill, Linda M.; Diniz-Filho, Alberto; Suh, Min Hee; Manalastas, Patricia Isabel; Fatehee, Naeem; Yousefi, Siamak; Belghith, Akram; Saunders, Luke J.; Medeiros, Felipe A.; Huang, David; Weinreb, Robert N.

    2016-01-01

    Purpose The purpose of this study was to compare retinal nerve fiber layer (RNFL) thickness and optical coherence tomography angiography (OCT-A) retinal vasculature measurements in healthy, glaucoma suspect, and glaucoma patients. Methods Two hundred sixty-one eyes of 164 healthy, glaucoma suspect, and open-angle glaucoma (OAG) participants from the Diagnostic Innovations in Glaucoma Study with good quality OCT-A images were included. Retinal vasculature information was summarized as a vessel density map and as vessel density (%), which is the proportion of flowing vessel area over the total area evaluated. Two vessel density measurements extracted from the RNFL were analyzed: (1) circumpapillary vessel density (cpVD) measured in a 750-μm-wide elliptical annulus around the disc and (2) whole image vessel density (wiVD) measured over the entire image. Areas under the receiver operating characteristic curves (AUROC) were used to evaluate diagnostic accuracy. Results Age-adjusted mean vessel density was significantly lower in OAG eyes compared with glaucoma suspects and healthy eyes. (cpVD: 55.1 ± 7%, 60.3 ± 5%, and 64.2 ± 3%, respectively; P glaucoma and healthy eyes, the age-adjusted AUROC was highest for wiVD (0.94), followed by RNFL thickness (0.92) and cpVD (0.83). The AUROCs for differentiating between healthy and glaucoma suspect eyes were highest for wiVD (0.70), followed by cpVD (0.65) and RNFL thickness (0.65). Conclusions Optical coherence tomography angiography vessel density had similar diagnostic accuracy to RNFL thickness measurements for differentiating between healthy and glaucoma eyes. These results suggest that OCT-A measurements reflect damage to tissues relevant to the pathophysiology of OAG. PMID:27409505

  4. Thermal-hydraulic analyses of pressurized-thermal-shock-induced vessel ruptures

    International Nuclear Information System (INIS)

    Dobranich, D.

    1982-05-01

    A severe overcooling transient was postulated to produce vessel wall temperatures below the nil-ductility transition temperature which in conjunction with system repressurization, led to vessel rupture at the core midplane. Such transients are referred to as pressurized-thermal-shock transients. A wide range of vessel rupture sizes were investigated to assess the emergency system's ability to cool the fuel rods. Ruptures greater than approximately 0.015 m 2 produced flows greater than those of the emergency system and resulted in core uncovery and subsequent core damage

  5. Long-term safety and feasibility of three-vessel multimodality intravascular imaging in patients with ST-elevation myocardial infarction

    DEFF Research Database (Denmark)

    Taniwaki, Masanori; Radu, Maria D; Garcia-Garcia, Hector M

    2015-01-01

    We assessed the feasibility and the procedural and long-term safety of intracoronary (i.c) imaging for documentary purposes with optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in patients with acute ST-elevation myocardial infarction (STEMI) undergoing primary PCI in the s......We assessed the feasibility and the procedural and long-term safety of intracoronary (i.c) imaging for documentary purposes with optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in patients with acute ST-elevation myocardial infarction (STEMI) undergoing primary PCI...... in the setting of IBIS-4 study. IBIS4 (NCT00962416) is a prospective cohort study conducted at five European centers including 103 STEMI patients who underwent serial three-vessel coronary imaging during primary PCI and at 13 months. The feasibility parameter was successful imaging, defined as the number...... of pullbacks suitable for analysis. Safety parameters included the frequency of peri-procedural complications, and major adverse cardiac events (MACE), a composite of cardiac death, myocardial infarction (MI) and any clinically-indicated revascularization at 2 years. Clinical outcomes were compared...

  6. Absorbed dose calculations to blood and blood vessels for internally deposited radionuclides

    International Nuclear Information System (INIS)

    Akabani, G.; Poston, J.W. Sr.

    1992-01-01

    At present, absorbed dose calculations for radionuclides in the human circulatory system use relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, Monte Carlo calculations were performed using the code Electron Gamma Shower (EGS4). Absorbed doses were calculated for the blood and the blood vessel wall (lumen) for different blood vessel sizes. The radionuclides chosen for this study were those commonly used in nuclear medicine. No diffusion of the radionuclide into the blood vessel was or cross fire between blood vessels was assumed. Results are useful in assessing the doses to blood and blood vessel walls for different nuclear medicine procedures

  7. Absorbed dose calculations to blood and blood vessels for internally deposited radionuclides

    International Nuclear Information System (INIS)

    Akabani, G.; Poston, J.W.

    1991-05-01

    At present, absorbed dose calculations for radionuclides in the human circulatory system used relatively simple models and are restricted in their applications. To determine absorbed doses to the blood and to the surface of the blood vessel wall, EGS4 Monte Carlo calculations were performed. Absorbed doses were calculated for the blood and the blood vessel wall (lumen) for different blood vessels sizes. The radionuclides chosen for this study were those commonly used in nuclear medicine. No diffusion of the radionuclide into the blood vessel was assumed nor cross fire between vessel was assumed. Results are useful in assessing the dose in blood and blood vessel walls for different nuclear medicine procedures. 6 refs., 6 figs., 5 tabs

  8. Defect sizing of post-irradiated nuclear fuels using grayscale thresholding in their radiographic images

    International Nuclear Information System (INIS)

    Chaudhary, Usman Khurshid; Iqbal, Masood; Ahmad, Munir

    2010-01-01

    Quantification of different types of material defects in a number of reference standard post-irradiated nuclear fuel image samples have been carried out by virtue of developing a computer program that takes radiographic images of the fuel as input. The program is based on user adjustable grayscale thresholding in the regime of image segmentation whereby it selects and counts the pixels having graylevel values less than or equal to the computed threshold. It can size the defects due to chipping in nuclear fuel, cracks, voids, melting, deformation, inclusion of foreign materials, heavy isotope accumulation, non-uniformity, etc. The classes of fuel range from those of research and power reactors to fast breeders and from pellets to annular and vibro-compacted fuel. The program has been validated against ground truth realities of some locally fabricated metallic plates having drilled holes of known sizes simulated as defects in them in which the results indicate that it either correctly selects and quantifies at least 94% of the actual required regions of interest in a given image or it gives less than 8.1% false alarm rate. Also, the developed program is independent of image size.

  9. Defect sizing of post-irradiated nuclear fuels using grayscale thresholding in their radiographic images

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhary, Usman Khurshid, E-mail: ukhurshid@hotmail.co [Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences, P.O. Nilore, Islamabad 45650 (Pakistan); Iqbal, Masood, E-mail: masiqbal@hotmail.co [Nuclear Engineering Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad 45650 (Pakistan); Ahmad, Munir [Nondestructive Testing Group, Directorate of Technology, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad 45650 (Pakistan)

    2010-10-15

    Quantification of different types of material defects in a number of reference standard post-irradiated nuclear fuel image samples have been carried out by virtue of developing a computer program that takes radiographic images of the fuel as input. The program is based on user adjustable grayscale thresholding in the regime of image segmentation whereby it selects and counts the pixels having graylevel values less than or equal to the computed threshold. It can size the defects due to chipping in nuclear fuel, cracks, voids, melting, deformation, inclusion of foreign materials, heavy isotope accumulation, non-uniformity, etc. The classes of fuel range from those of research and power reactors to fast breeders and from pellets to annular and vibro-compacted fuel. The program has been validated against ground truth realities of some locally fabricated metallic plates having drilled holes of known sizes simulated as defects in them in which the results indicate that it either correctly selects and quantifies at least 94% of the actual required regions of interest in a given image or it gives less than 8.1% false alarm rate. Also, the developed program is independent of image size.

  10. Usefulness of virtual endoscopy for evaluating the relationship between the neck of intracranial aneurysm and surrounding vessels

    International Nuclear Information System (INIS)

    Ikeda, Jota; Horie, Hitoshi; Ishikura, Reiichi; Ando, Kumiko; Morikawa, Tsutomu; Tominaga, Satoru; Nakao, Norio

    2000-01-01

    Application of three-dimensional CT virtual endoscopy for evaluation of the neck and surrounding vessels of intracranial aneurysms. 3D-CT virtual endoscopy (VE) is a reconstructed image using computer processing of 3D-CT images. We evaluated the usefulness of a virtual endoscopy to analyze the relationship between the neck of an intracranial aneurysm and the surrounding vessels. Eight cases with intracranial aneurysms underwent digital subtraction angiography (DSA) and enhanced CT with transarterial infusion of contrast media. 3D-CT angiogram (3D-CTA) and virtual endoscopic images were obtained from the CT image data sets using surface rendering method. The relationship between the neck of an intracranial aneurysm and the surrounding vessels was confirmed by operation or IVR. VE clearly visualized the neck and surrounding vessels in all cases. Operation/IVR findings agreed with the virtual endoscopic findings in all cases, but not with the DSA or 3D-CTA findings in 4 and 2 cases, respectively. 3D-CTA and virtual endoscopy clearly visualizes the relationship between cerebral aneurysms and surrounding vessels, which is useful for determining IVR procedures. (author)

  11. Novel Volumetric Size and Velocity Measurement of Particles Using Interferometric Laser Imaging

    Science.gov (United States)

    Gunawardana, R.; Zarzecki, M.; Diez, F. J.

    2008-11-01

    Global Sizing Velocimetry (GSV) is a recently developed technique for characterizing the particle size distribution and flow velocity in a plane and in this research we extend this measurement to a volume through a laser scanning system. In GSV, a LASER sheet is used to illuminate translucent particles in a spray or flow field and the camera image is de-focused a known distance to create interference patterns. The diameters of the particles in the flow field are calculated by measuring the inter-fringe spacing in the resulting interferogram. Particle Imaging Velocimetry (PIV) techniques are used to compute velocity by measuring the particle displacement over a known short time interval. Researchers have recently begun applying GSV techniques to characterize sprays in a plane as it offers a larger area of investigation than other well known techniques such as Phase Doppler Anemometry (PDA). In this paper we extend GSA techniques from the current planar measurements to a volumetric measurement. The approach uses a high speed camera to acquire GSA images by scanning multiple planes in a volume of the flow field within a short period of time and obtain particle size distribution and velocity measurements in the entire volume.

  12. Rupture tests with reactor pressure vessel head models

    International Nuclear Information System (INIS)

    Talja, H.; Keinaenen, H.; Hosio, E.; Pankakoski, P.H.; Rahka, K.

    2003-01-01

    In the LISSAC project (LImit Strains in Severe ACcidents), partly funded by the EC Nuclear Fission and Safety Programme within the 5th Framework programme, an extensive experimental and computational research programme is conducted to study the stress state and size dependence of ultimate failure strains. The results are aimed especially to make the assessment of severe accident cases more realistic. For the experiments in the LISSAC project a block of material of the German Biblis C reactor pressure vessel was available. As part of the project, eight reactor pressure vessel head models from this material (22 NiMoCr 3 7) were tested up to rupture at VTT. The specimens were provided by Forschungszentrum Karlsruhe (FzK). These tests were performed under quasistatic pressure load at room temperature. Two specimens sizes were tested and in half of the tests the specimens contain holes describing the control rod penetrations of an actual reactor pressure vessel head. These specimens were equipped with an aluminium liner. All six tests with the smaller specimen size were conducted successfully. In the test with the large specimen with holes, the behaviour of the aluminium liner material proved to differ from those of the smaller ones. As a consequence the experiment ended at the failure of the liner. The specimen without holes yielded results that were in very good agreement with those from the small specimens. (author)

  13. Comparative Study of Retinal Vessel Segmentation Based on Global Thresholding Techniques

    Directory of Open Access Journals (Sweden)

    Temitope Mapayi

    2015-01-01

    Full Text Available Due to noise from uneven contrast and illumination during acquisition process of retinal fundus images, the use of efficient preprocessing techniques is highly desirable to produce good retinal vessel segmentation results. This paper develops and compares the performance of different vessel segmentation techniques based on global thresholding using phase congruency and contrast limited adaptive histogram equalization (CLAHE for the preprocessing of the retinal images. The results obtained show that the combination of preprocessing technique, global thresholding, and postprocessing techniques must be carefully chosen to achieve a good segmentation performance.

  14. In-vivo imaging of blood flow in human retinal vessels using color Doppler optical coherence tomography

    Science.gov (United States)

    Yazdanfar, Siavash; Rollins, Andrew M.; Izatt, Joseph A.

    1999-04-01

    Quantification of retinal blood flow may lead to a better understanding of the progression and treatment of several ocular disorders, including diabetic retinopathy, age- related macular degeneration, and glaucoma. Current techniques, such as fluorescein angiography and laser Doppler velocimetry are limited, failing to provide sufficient information to the clinician. Color Doppler optical coherence tomography (CDOCT) is a novel technique using coherent heterodyne detection for simultaneous cross- sectional imaging of tissue microstructure and blood flow. This technique is capable of high spatial and velocity resolution imaging in highly scattering media. We implemented CDOCT for retinal blood flow mapping in human subjects. No dilation of the pupil was necessary. CDOCT is demonstrated for determining bidirectional flow in sub- 100micrometers diameter vessels in the retina. Additionally, we calculated Doppler broadening using the variance of depth- resolved spectra to identify regions with large velocity gradients within the Xenopus heart. This technique may be useful in quantifying local tissue perfusion in highly vascular retinal tissue.

  15. Cardiac magnetic resonance imaging in children

    International Nuclear Information System (INIS)

    Helbing, Willem A.; Ouhlous, Mohamed

    2015-01-01

    MRI is an important additional tool in the diagnostic work-up of children with congenital heart disease. This review aims to summarise the role MRI has in this patient population. Echocardiography remains the main diagnostic tool in congenital heart disease. In specific situations, MRI is used for anatomical imaging of congenital heart disease. This includes detailed assessment of intracardiac anatomy with 2-D and 3-D sequences. MRI is particularly useful for assessment of retrosternal structures in the heart and for imaging large vessel anatomy. Functional assessment includes assessment of ventricular function using 2-D cine techniques. Of particular interest in congenital heart disease is assessment of right and single ventricular function. Two-dimensional and newer 3-D techniques to quantify flow in these patients are or will soon become an integral part of quantification of shunt size, valve function and complex flow patterns in large vessels. More advanced uses of MRI include imaging of cardiovascular function during stress and tissue characterisation of the myocardium. Techniques used for this purpose need further validation before they can become part of the daily routine of MRI assessment of congenital heart disease. (orig.)

  16. A new approach of recognition of ellipsoidal micro- and nanoparticles on AFM images and determination of their sizes

    International Nuclear Information System (INIS)

    Akhmadeev, Albert A; Kh Salakhov, Myakzyum

    2016-01-01

    In this work we develop an approach of automatic recognition of ellipsoidal particles on the atomic force microscopy (AFM) image and determination of their size, which is based on image segmentation and the surface approximation by ellipsoids. In addition to the comparative simplicity and rapidity of processing, this method allows us to determine the size of particles, the surface of which is not completely visible on the image. The proposed method showed good results on simulated images including noisy ones. Using this algorithm the size distributions of silica particles on experimental AFM images have been determined. (paper)

  17. VISA-2, Reactor Vessel Failure Probability Under Thermal Shock

    International Nuclear Information System (INIS)

    Simonen, F.; Johnson, K.

    1992-01-01

    1 - Description of program or function: VISA2 (Vessel Integrity Simulation Analysis) was developed to estimate the failure probability of nuclear reactor pressure vessels under pressurized thermal shock conditions. The deterministic portion of the code performs heat transfer, stress, and fracture mechanics calculations for a vessel subjected to a user-specified temperature and pressure transient. The probabilistic analysis performs a Monte Carlo simulation to estimate the probability of vessel failure. Parameters such as initial crack size and position, copper and nickel content, fluence, and the fracture toughness values for crack initiation and arrest are treated as random variables. Linear elastic fracture mechanics methods are used to model crack initiation and growth. This includes cladding effects in the heat transfer, stress, and fracture mechanics calculations. The simulation procedure treats an entire vessel and recognizes that more than one flaw can exist in a given vessel. The flaw model allows random positioning of the flaw within the vessel wall thickness, and the user can specify either flaw length or length-to-depth aspect ratio for crack initiation and arrest predictions. The flaw size distribution can be adjust on the basis of different inservice inspection techniques and inspection conditions. The toughness simulation model includes a menu of alternative equations for predicting the shift in the reference temperature of the nil-ductility transition. 2 - Method of solution: The solution method uses closed form equations for temperatures, stresses, and stress intensity factors. A polynomial fitting procedure approximates the specified pressure and temperature transient. Failure probabilities are calculated by a Monte Carlo simulation. 3 - Restrictions on the complexity of the problem: Maxima of 30 welds. VISA2 models only the belt-line (cylindrical) region of a reactor vessel. The stresses are a function of the radial (through-wall) coordinate only

  18. Histomorphological changes of vessel structure in head and neck vessels following preoperative or postoperative radiotherapy

    International Nuclear Information System (INIS)

    Schultze-Mosgau, S.; Wehrhan, F.; Wiltfang, J.; Grabenbauer, G.G.; Sauer, R.; Roedel, F.; Radespiel-Troeger, M.

    2002-01-01

    Patients and Methods: In 348 patients (October 1995-March 2002) receiving primarly or secondarily 356 microvascular hard- and soft tissue reconstruction, a total of 209 vessels were obtained from neck recipient vessels and transplant vessels during anastomosis. Three groups were analysed: group 1 (27 patients) treated with no radiotherapy or chemotherapy; group 2 (29 patients) treated with preoperative irradiation (40-50 Gy) and chemotherapy (800 mg/m 2 /day 5-FU and 20 mg/m 2 /day cisplatin) 1.5 months prior to surgery; group 3 (20 patients) treated with radiotherapy (60-70 Gy) (median interval 78.7 months; IQR: 31.3 months) prior to surgery. From each of the 209 vessel specimens, 3 sections were investigated histomorphometrically, qualitatively and quantitatively (ratio media area/total vessel area) by NIH-Image-digitized measurements. To evaluate these changes as a function of age, radiation dose and chemotherapy, a statistical analysis was performed using an analysis of covariance and χ 2 tests (p > 0.05, SPSS V10). Results: In group 3, qualitative changes (intima dehiscence, hyalinosis) were found in recipient arteries significantly more frequently than in groups 1 and 2. For group 3 recipient arteries, histomorphometry revealed a significant decrease in the ratio media area/total vessel area (median 0.51, IQR 0.10) in comparison with groups 1 (p = 0.02) (median 0.61, IQR 0.29) and 2 (p = 0.046) (median 0.58, IQR 0.19). No significant difference was found between the vessels of groups 1 and 2 (p = 0.48). There were no significant differences in transplant arteries and recipient or transplant veins between the groups. Age and chemotherapy did not appear to have a significant influence on vessel changes in this study (p > 0.05). Conclusions: Following irradiation with 60-70 Gy, significant qualitative and quantitative histological changes to the recipient arteries, but not to the recipient veins, could be observed. In contrast, irradiation at a dose of 40-50 Gy

  19. Comparison of known food weights with image-based portion-size automated estimation and adolescents' self-reported portion size.

    Science.gov (United States)

    Lee, Christina D; Chae, Junghoon; Schap, TusaRebecca E; Kerr, Deborah A; Delp, Edward J; Ebert, David S; Boushey, Carol J

    2012-03-01

    Diet is a critical element of diabetes self-management. An emerging area of research is the use of images for dietary records using mobile telephones with embedded cameras. These tools are being designed to reduce user burden and to improve accuracy of portion-size estimation through automation. The objectives of this study were to (1) assess the error of automatically determined portion weights compared to known portion weights of foods and (2) to compare the error between automation and human. Adolescents (n = 15) captured images of their eating occasions over a 24 h period. All foods and beverages served were weighed. Adolescents self-reported portion sizes for one meal. Image analysis was used to estimate portion weights. Data analysis compared known weights, automated weights, and self-reported portions. For the 19 foods, the mean ratio of automated weight estimate to known weight ranged from 0.89 to 4.61, and 9 foods were within 0.80 to 1.20. The largest error was for lettuce and the most accurate was strawberry jam. The children were fairly accurate with portion estimates for two foods (sausage links, toast) using one type of estimation aid and two foods (sausage links, scrambled eggs) using another aid. The automated method was fairly accurate for two foods (sausage links, jam); however, the 95% confidence intervals for the automated estimates were consistently narrower than human estimates. The ability of humans to estimate portion sizes of foods remains a problem and a perceived burden. Errors in automated portion-size estimation can be systematically addressed while minimizing the burden on people. Future applications that take over the burden of these processes may translate to better diabetes self-management. © 2012 Diabetes Technology Society.

  20. Measuring Restriction Sizes Using Diffusion Weighted Magnetic Resonance Imaging: A Review

    Directory of Open Access Journals (Sweden)

    Melanie Martin

    2013-01-01

    Full Text Available This article reviews a new concept in magnetic resonance as applied to cellular and biological systems. Diffusion weighted magnetic resonance imaging can be used to infer information about restriction sizes of samples being measured. The measurements rely on the apparent diffusion coefficient changing with diffusion times as measurements move from restricted to free diffusion regimes. Pulsed gradient spin echo (PGSE measurements are limited in the ability to shorten diffusion times and thus are limited in restriction sizes which can be probed. Oscillating gradient spin echo (OGSE measurements could provide shorter diffusion times so smaller restriction sizes could be probed.

  1. Fuel-coolant interaction visualization test for in-vessel corium retention external reactor vessel cooling (IVR-ERVC) condition

    Energy Technology Data Exchange (ETDEWEB)

    Na, Young Su; Hong, Seong Ho; Song, Jin Ho; Hong, Seong Wan [Severe Accident and PHWR Safety Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-12-15

    A visualization test of the fuel-coolant interaction in the Test for Real cOrium Interaction with water (TROI) test facility was carried out. To experimentally simulate the In-Vessel corium Retention (IVR)- External Reactor Vessel Cooling (ERVC) conditions, prototypic corium was released directly into the coolant water without a free fall in a gas phase before making contact with the coolant. Corium (34.39 kg) consisting of uranium oxide and zirconium oxide with a weight ratio of 8:2 was superheated, and 22.54 kg of the 34.39 kg corium was passed through water contained in a transparent interaction vessel. An image of the corium jet behavior in the coolant was taken by a high-speed camera every millisecond. Thermocouple junctions installed in the vertical direction of the coolant were cut sequentially by the falling corium jet. It was clearly observed that the visualization image of the corium jet taken during the fuel-coolant interaction corresponded with the temperature variations in the direction of the falling melt. The corium penetrated through the coolant, and the jet leading edge velocity was 2.0 m/s. Debris smaller than 1 mm was 15% of the total weight of the debris collected after a fuel-coolant interaction test, and the mass median diameter was 2.9 mm.

  2. Practical Application Limits of Fuel Cells and Batteries for Zero Emission Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Minnehan, John J. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Energy Innovation Dept.; Pratt, Joseph William [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Energy Innovation Dept.

    2017-11-01

    Batteries and hydrogen fuel cells provide zero emission power at the point of use. They are studied as an alternative powerplant for maritime vessels by considering 14 case studies of various ship sizes and routes varying from small passenger vessels to the largest cargo ships. The method used was to compare the mass and volume of the required zero emission solution to the available mass and volume on an existing vessel considering its current engine and fuel storage systems. The results show that it is practically feasible to consider these zero emission technologies for most vessels in the world's fleet. Hydrogen fuel cells proved to be the most capable while battery systems showed an advantage for high power, short duration missions. The results provide a guide to ship designers to determine the most suitable types of zero emission powerplants to fit a ship based on its size and energy requirements.

  3. Improvements in the Quantitative Assessment of Cerebral Blood Volume and Flow with the Removal of Vessel Voxels from MR Perfusion Images

    Directory of Open Access Journals (Sweden)

    Michael Mu Huo Teng

    2013-01-01

    Full Text Available Objective. To improve the quantitative assessment of cerebral blood volume (CBV and flow (CBF in the brain voxels from MR perfusion images. Materials and Methods. Normal brain parenchyma was automatically segmented with the time-to-peak criteria after cerebrospinal fluid removal and preliminary vessel voxel removal. Two scaling factors were calculated by comparing the relative CBV and CBF of the segmented normal brain parenchyma with the absolute values in the literature. Using the scaling factors, the relative values were converted to the absolute CBV and CBF. Voxels with either CBV > 8 mL/100 g or CBF > 100 mL/100 g/min were characterized as vessel voxels and were excluded from the quantitative measurements. Results. The segmented brain parenchyma with normal perfusion was consistent with the angiographic findings for each patient. We confirmed the necessity of dual thresholds including CBF and CBV for proper removal of vessel voxels. The scaling factors were 0.208 ± 0.041 for CBV, and 0.168 ± 0.037, 0.172 ± 0.037 for CBF calculated using standard and circulant singular value decomposition techniques, respectively. Conclusion. The automatic scaling and vessel removal techniques provide an alternative method for obtaining improved quantitative assessment of CBV and CBF in patients with thromboembolic cerebral arterial disease.

  4. [Key vessels assessment and operation highlights in laparoscopic extended right hemicolectomy].

    Science.gov (United States)

    Wang, Hao; Zhao, Quanquan

    2018-03-25

    Laparoscopic radical colectomies have been more widely used gradually, among which laparoscopic extended right hemicolectomy is considered as the most difficult procedure. The difficulty of extended right hemicolectomy lies in the need to dissect lymph nodes along the superior mesenteric vein (SMV) and disconnect numerous and possible aberrant vessels. To address this problem, we emphasize two points in key vessel assessment: getting familiar with the anatomy along the medial-to-lateral approach and having a good understanding about the preoperative imaging presentations. An accurately preoperative imaging assessment by abdominal enhanced CT can help the surgeon understand the relative position of the key vessels to be dealt with during operation and the situation of the possible aberrant vessels so as to guide the procedure more effectively and facilitate the prevention and management of the intraoperative complications. During operation, the operator should pay special attention to the management of the vessels in the ileocolic vessel region, Henle's trunk and middle colon vessels. The operation highlights of the key vessels are as follows: (1) The ileocolic vessels: identifying the Toldt's gap correctly and opening the vascular sheath of the SMV securely; making sure that the duodenum is well protected. (2) Henle's trunk: dissecting along the surface of the Henle's trunk; preserving the anterior superior pancreaticoduodenal vein (ASPDV) and main trunk of the Henle's trunk; disconnecting the roots of the right colic vein (RCV) and right gastroepiploic vein (RGEV), and then dissecting lymph nodes along the surface of the pancreas. (3) The middle colon vessels: identifying the root of the middle colon vessel along the lower edge of the pancreas; avoiding entering behind the pancreas; mobilizing the transverse mesocolon sufficiently along the surface of the pancreas. Finally, we discuss and analyze the disputes currently existing in laparoscopic extended right

  5. Offshore wind transport and installation vessel

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The initial objective of the project was to complete a feasibility study to determine the viability of an innovative transportation vessel to be deployed in the installation of offshore wind farms. This included the feasibility of providing a stable-working platform that can be used in harsh offshore environments. A study of current installation contractors and their installation equipment was used to provide a preliminary specification for the installation vessel. A typical barge was selected and a number of hydrodynamic analyses were carried out in order to establish it's on course and operational stability. The analysis proved the stability of the vessel during operation was critical and that in order to utilise the crane's full potential a stabilisation system must be employed. The main aim of the work to date was to establish whether it was feasible to use a stabilisation system on the installation vessel. The spud leg FEED study established that it was feasible to use spud legs to stabilise the vessel. In order to achieve the degree of stability required it is necessary to lift the vessel completely out of the water. This was not the original aim of the study but due to the external loads on the hull it was the only viable option. Lifting the vessel out of the water results in the legs and leg casings becoming very large. This has a number of consequences for the final design. Due to large loads on the legs spud cans must be used to avoid bottom penetration, the spud cans increase the draft of the vessel by 2m. The large loads require larger winches and more reeving to be used, this results in larger pumps and motors, all of which have to be housed. The stabilisation system has been proved to be feasible for a large installation vessel, the cost and physical size are however more excessive than first anticipated. (Author)

  6. Fouling in your own nest: vessel noise increases biofouling.

    Science.gov (United States)

    Stanley, Jenni A; Wilkens, Serena L; Jeffs, Andrew G

    2014-01-01

    Globally billions of dollars are spent each year on attempting to reduce marine biofouling on commercial vessels, largely because it results in higher fuel costs due to increased hydrodynamic drag. Biofouling has been long assumed to be primarily due to the availability of vacant space on the surface of the hull. Here, it is shown that the addition of the noise emitted through a vessel's hull in port increases the settlement and growth of biofouling organisms within four weeks of clean surfaces being placed in the sea. More than twice as many bryozoans, oysters, calcareous tube worms and barnacles settled and established on surfaces with vessel noise compared to those without. Likewise, individuals from three species grew significantly larger in size in the presence of vessel noise. The results demonstrate that vessel noise in port is promoting biofouling on hulls and that underwater sound plays a much wider ecological role in the marine environment than was previously considered possible.

  7. Detection of hypertensive retinopathy using vessel measurements and textural features.

    Science.gov (United States)

    Agurto, Carla; Joshi, Vinayak; Nemeth, Sheila; Soliz, Peter; Barriga, Simon

    2014-01-01

    Features that indicate hypertensive retinopathy have been well described in the medical literature. This paper presents a new system to automatically classify subjects with hypertensive retinopathy (HR) using digital color fundus images. Our method consists of the following steps: 1) normalization and enhancement of the image; 2) determination of regions of interest based on automatic location of the optic disc; 3) segmentation of the retinal vasculature and measurement of vessel width and tortuosity; 4) extraction of color features; 5) classification of vessel segments as arteries or veins; 6) calculation of artery-vein ratios using the six widest (major) vessels for each category; 7) calculation of mean red intensity and saturation values for all arteries; 8) calculation of amplitude-modulation frequency-modulation (AM-FM) features for entire image; and 9) classification of features into HR and non-HR using linear regression. This approach was tested on 74 digital color fundus photographs taken with TOPCON and CANON retinal cameras using leave-one out cross validation. An area under the ROC curve (AUC) of 0.84 was achieved with sensitivity and specificity of 90% and 67%, respectively.

  8. Radiation-Force Assisted Targeting Facilitates Ultrasonic Molecular Imaging

    Directory of Open Access Journals (Sweden)

    Shukui Zhao

    2004-07-01

    Full Text Available Ultrasonic molecular imaging employs contrast agents, such as microbubbles, nanoparticles, or liposomes, coated with ligands specific for receptors expressed on cells at sites of angiogenesis, inflammation, or thrombus. Concentration of these highly echogenic contrast agents at a target site enhances the ultrasound signal received from that site, promoting ultrasonic detection and analysis of disease states. In this article, we show that acoustic radiation force can be used to displace targeted contrast agents to a vessel wall, greatly increasing the number of agents binding to available surface receptors. We provide a theoretical evaluation of the magnitude of acoustic radiation force and show that it is possible to displace micron-sized agents physiologically relevant distances. Following this, we show in a series of experiments that acoustic radiation force can enhance the binding of targeted agents: The number of biotinylated microbubbles adherent to a synthetic vessel coated with avidin increases as much as 20-fold when acoustic radiation force is applied; the adhesion of contrast agents targeted to αvβ3 expressed on human umbilical vein endothelial cells increases 27-fold within a mimetic vessel when radiation force is applied; and finally, the image signal-to-noise ratio in a phantom vessel increases up to 25 dB using a combination of radiation force and a targeted contrast agent, over use of a targeted contrast agent alone.

  9. Automated identification of retinal vessels using a multiscale directional contrast quantification (MDCQ) strategy

    Energy Technology Data Exchange (ETDEWEB)

    Zhen, Yi; Zhang, Xinyuan; Wang, Ningli, E-mail: wningli@vip.163.com, E-mail: puj@upmc.edu [National Engineering Research Center for Ophthalmic Equipments, Beijing, 100730 (China); Gu, Suicheng; Meng, Xin [Imaging Research Center, Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213 (United States); Zheng, Bin [School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019 (United States); Pu, Jiantao, E-mail: wningli@vip.163.com, E-mail: puj@upmc.edu [Imaging Research Center, Departments of Radiology and Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213 (United States)

    2014-09-15

    Purpose: A novel algorithm is presented to automatically identify the retinal vessels depicted in color fundus photographs. Methods: The proposed algorithm quantifies the contrast of each pixel in retinal images at multiple scales and fuses the resulting consequent contrast images in a progressive manner by leveraging their spatial difference and continuity. The multiscale strategy is to deal with the variety of retinal vessels in width, intensity, resolution, and orientation; and the progressive fusion is to combine consequent images and meanwhile avoid a sudden fusion of image noise and/or artifacts in space. To quantitatively assess the performance of the algorithm, we tested it on three publicly available databases, namely, DRIVE, STARE, and HRF. The agreement between the computer results and the manual delineation in these databases were quantified by computing their overlapping in both area and length (centerline). The measures include sensitivity, specificity, and accuracy. Results: For the DRIVE database, the sensitivities in identifying vessels in area and length were around 90% and 70%, respectively, the accuracy in pixel classification was around 99%, and the precisions in terms of both area and length were around 94%. For the STARE database, the sensitivities in identifying vessels were around 90% in area and 70% in length, and the accuracy in pixel classification was around 97%. For the HRF database, the sensitivities in identifying vessels were around 92% in area and 83% in length for the healthy subgroup, around 92% in area and 75% in length for the glaucomatous subgroup, around 91% in area and 73% in length for the diabetic retinopathy subgroup. For all three subgroups, the accuracy was around 98%. Conclusions: The experimental results demonstrate that the developed algorithm is capable of identifying retinal vessels depicted in color fundus photographs in a relatively reliable manner.

  10. Application of blood-pool agents in visualization of peripheral vessels

    International Nuclear Information System (INIS)

    Giovagnoni, A.; Catalano, C.

    2007-01-01

    Effective arterial imaging is essential in patients with peripheral arterial disease (PAD) in whom a revascularization procedure is planned. Digital subtraction angiography (DSA) has traditionally been regarded as the gold standard for imaging in peripheral arterial disease, but this technique is subject to certain limitations, such as the risks of adverse reactions associated with arterial catheterization and iodinated contrast agents. Contrast-enhanced magnetic resonance angiography is now recommended as an effective and useful imaging technique in peripheral arterial disease, since it offers high enhanced contrast between blood and stationary tissue and fast acquisition times. However, extracellular gadolinium contrast agents rapidly diffuse into the interstitial spaces, and thus are suitable only for first-pass imaging. This limitation can be overcome by the use of blood-pool (intravascular) contrast agents, such as gadofosveset trisodium (Vasovist, Bayer Schering Pharma AG, Berlin, Germany), which are retained within the blood vessels and hence facilitate both first-pass and steady-state imaging with high spatial resolution. Blood-pool agents, therefore, offer improved imaging, particularly of distal vessels, compared with extracellular contrast agents. Examples of first-pass and steady-state imaging with gadofosveset are presented. (orig.)

  11. Safety of nuclear pressure vessels and its regulatory aspects in France

    Energy Technology Data Exchange (ETDEWEB)

    de Torquat, G; Queniart, D; Barrachin, B; Roche, R

    1979-01-01

    Having outlined the basic French regulations governing the safety of both pressure vessels and also of nuclear installations in general the particular safety regulations covering prestressed concrete vessels for nuclear reactors are considered. The regulations now being prepared to cover heat transfer systems of water reactors are detailed under sections headed; general provisions, sizing, and construction.

  12. Combining endoscopes with PIV and digital holography for the study of vessel model mechanics

    International Nuclear Information System (INIS)

    Arévalo, Laura; Palero, Virginia; Andrés, Nieves; Arroyo, M P; Lobera, Julia

    2015-01-01

    In this work traditional fluid and solid mechanics measurement techniques have been combined with endoscopes for the study of blood vessel models’ mechanical properties. Endoscopes have been used as the imaging part of a high-speed PIV system to obtain the velocity field in a vessel model immersed in a container with a refractive index-matching liquid. In this way, we take advantage of the fact that the endoscope tip can be immersed in liquid. Endoscopes have also been used as the imaging and illuminating part of a digital holographic set-up for wall deformation measurement. The novelty of this work is that only one endoscope was used for illuminating and observing the vessel model, using the endoscope’s own illuminating system as the illumination source. The performance of endoscopes in different vessel models has been tested. The results of flow velocity and wall deformation in the different blood vessel models are presented. (paper)

  13. Enhancement of optic cup detection through an improved vessel kink detection framework

    Science.gov (United States)

    Wong, Damon W. K.; Liu, Jiang; Tan, Ngan Meng; Zhang, Zhuo; Lu, Shijian; Lim, Joo Hwee; Li, Huiqi; Wong, Tien Yin

    2010-03-01

    Glaucoma is a leading cause of blindness. The presence and extent of progression of glaucoma can be determined if the optic cup can be accurately segmented from retinal images. In this paper, we present a framework which improves the detection of the optic cup. First, a region of interest is obtained from the retinal fundus image, and a pallor-based preliminary cup contour estimate is determined. Patches are then extracted from the ROI along this contour. To improve the usability of the patches, adaptive methods are introduced to ensure the patches are within the optic disc and to minimize redundant information. The patches are then analyzed for vessels by an edge transform which generates pixel segments of likely vessel candidates. Wavelet, color and gradient information are used as input features for a SVM model to classify the candidates as vessel or non-vessel. Subsequently, a rigourous non-parametric method is adopted in which a bi-stage multi-resolution approach is used to probe and localize the location of kinks along the vessels. Finally, contenxtual information is used to fuse pallor and kink information to obtain an enhanced optic cup segmentation. Using a batch of 21 images obtained from the Singapore Eye Research Institute, the new method results in a 12.64% reduction in the average overlap error against a pallor only cup, indicating viable improvements in the segmentation and supporting the use of kinks for optic cup detection.

  14. New aspects of MRI for diagnostics of large vessel vasculitis and primary angiitis of the central nervous system

    International Nuclear Information System (INIS)

    Saam, T.; Habs, M.; Cyran, C.C.; Grimm, J.; Reiser, M.F.; Nikolaou, K.; Pfefferkorn, T.; Schueller, U.

    2010-01-01

    Vasculitis is a rare disease and clinical symptoms are often unspecific. Accurate and early diagnosis is mandatory in order to prevent complications, such as loss of vision or stroke. Imaging techniques can contribute to establishing a definite diagnosis and to evaluate disease activity and the extent of the disease in various vascular regions. Conventional imaging methods, such as computed tomography (CT) and magnetic resonance (MR) angiography, as well as digital subtraction angiography allow the vessel lumen but not the vessel wall to be depicted. However, vasculitis is a disease which primarily affects the vessel wall, therefore conventional imaging modalities often fail to make a definite diagnosis. Recently black-blood high resolution MR in vivo imaging has been used to visualize cervical and intracranial vasculitis. This review article presents imaging protocols for intracranial and cervical black-blood MR imaging and clinical cases with large vessel vasculitis and vasculitis of the central nervous system. Furthermore the current literature, examples of the most common differential diagnoses of cervical and cranial arteriopathy and the potential of other imaging modalities, such as PET/CT and ultrasound will be discussed. (orig.) [de

  15. Free radical scavenger, edaravone, reduces the lesion size of lacunar infarction in human brain ischemic stroke

    Science.gov (United States)

    2011-01-01

    Background Although free radicals have been reported to play a role in the expansion of ischemic brain lesions, the effect of free radical scavengers is still under debate. In this study, the temporal profile of ischemic stroke lesion sizes was assessed for more than one year to evaluate the effect of edaravone which might reduce ischemic damage. Methods We sequentially enrolled acute ischemic stroke patients, who admitted between April 2003 and March 2004, into the edaravone(-) group (n = 83) and, who admitted between April 2004 and March 2005, into the edaravone(+) group (n = 93). Because, edaravone has been used as the standard treatment after April 2004 in our hospital. To assess the temporal profile of the stroke lesion size, the ratio of the area [T2-weighted magnetic resonance images (T2WI)/iffusion-weighted magnetic resonance images (DWI)] were calculated. Observations on T2WI were continued beyond one year, and observational times were classified into subacute (1-2 months after the onset), early chronic (3-6 month), late chronic (7-12 months) and old (≥13 months) stages. Neurological deficits were assessed by the National Institutes of Health Stroke Scale upon admission and at discharge and by the modified Rankin Scale at 1 year following stroke onset. Results Stroke lesion size was significantly attenuated in the edaravone(+) group compared with the edaravone(-) group in the period of early and late chronic observational stages. However, this reduction in lesion size was significant within a year and only for the small-vessel occlusion stroke patients treated with edaravone. Moreover, patients with small-vessel occlusion strokes that were treated with edaravone showed significant neurological improvement during their hospital stay, although there were no significant differences in outcome one year after the stroke. Conclusion Edaravone treatment reduced the volume of the infarct and improved neurological deficits during the subacute period, especially

  16. Free radical scavenger, edaravone, reduces the lesion size of lacunar infarction in human brain ischemic stroke

    Directory of Open Access Journals (Sweden)

    Suzuki Akifumi

    2011-03-01

    Full Text Available Abstract Background Although free radicals have been reported to play a role in the expansion of ischemic brain lesions, the effect of free radical scavengers is still under debate. In this study, the temporal profile of ischemic stroke lesion sizes was assessed for more than one year to evaluate the effect of edaravone which might reduce ischemic damage. Methods We sequentially enrolled acute ischemic stroke patients, who admitted between April 2003 and March 2004, into the edaravone(- group (n = 83 and, who admitted between April 2004 and March 2005, into the edaravone(+ group (n = 93. Because, edaravone has been used as the standard treatment after April 2004 in our hospital. To assess the temporal profile of the stroke lesion size, the ratio of the area [T2-weighted magnetic resonance images (T2WI/iffusion-weighted magnetic resonance images (DWI] were calculated. Observations on T2WI were continued beyond one year, and observational times were classified into subacute (1-2 months after the onset, early chronic (3-6 month, late chronic (7-12 months and old (≥13 months stages. Neurological deficits were assessed by the National Institutes of Health Stroke Scale upon admission and at discharge and by the modified Rankin Scale at 1 year following stroke onset. Results Stroke lesion size was significantly attenuated in the edaravone(+ group compared with the edaravone(- group in the period of early and late chronic observational stages. However, this reduction in lesion size was significant within a year and only for the small-vessel occlusion stroke patients treated with edaravone. Moreover, patients with small-vessel occlusion strokes that were treated with edaravone showed significant neurological improvement during their hospital stay, although there were no significant differences in outcome one year after the stroke. Conclusion Edaravone treatment reduced the volume of the infarct and improved neurological deficits during the subacute

  17. Detection and sizing of inside-surface cracks in reactor pressure vessels

    International Nuclear Information System (INIS)

    Kamata, Hiroshi; Kanazawa, Katsuo; Satoh, Kunio; Honma, Takashi

    1984-01-01

    According to the past operational experience of LWRs, most of the defects arising in reactor pressure vessels accompanying operation are cracks occurring in the build up welding of austenitic stainless steel on the internal surfaces. The detection of these cracks has been carried out by ultrasonic flaw detection from outside in BWRs and from inside in PWRs as in-service inspection. However, there are difficulties such as ultrasonic echoes often occur though defects do not exist, and the quantitative evaluation of detected cracks is difficult by this method because of its accuracy. One of the means to reduce the first difficulty is to use eddy current method together to help the judgement, and for overcoming the second, the ultrasonic method catching end peak echo, that catching diffracted waves, eddy current method and electric resistance method were tried and compared. It is desirable to detect cracks in early stage before they reach parent material. The techniques to detect cracks on the internal surfaces of pressure vessels from the inside and to measure the depth are reported in this paper. The methods of flaw detection examined and the instruments used, the experimental method and the results are reported. It was concluded that eddy current method can be used as the backup for ultrasonic remote flaw detection, and the accuracy of depth measurement was the highest in ultrasonic diffraction wave method. (Kako, I.)

  18. Development and application of an LWR reactor pressure vessel-specific flaw distribution

    International Nuclear Information System (INIS)

    Rosinski, S.T.; Kennedy, E.L.; Foulds, J.R.

    1991-01-01

    Previous efforts by the US Department of Energy have shown that the PWR reactor vessel integrity predictions performed through probabilistic fracture mechanics analysis for a pressurized thermal shock event are significantly sensitive to the overall flaw distribution input. It has also been shown that modern vessel in-service inspection (ISI) results can be used for development of vessel flaw distribution(s) that are more representative of US vessels. This paper describes the development and application of a methodology to analyze ISI data for the purpose of flaw distribution determination. The resultant methodology considers detection reliability, flaw sizing accuracy, and flaw detection threshold in its application. Application of the methodology was then demonstrated using four recently acquired US PWR vessel inspection data sets. The methodology helped provide original insight into several key inspection performance and vessel integrity prediction practice issues that will impact future vessel integrity evaluation. This paper briefly discusses the development and application of the methodology and the impact to future vessel integrity analyses

  19. An experimental system for the study of ultrasound exposure of isolated blood vessels

    NARCIS (Netherlands)

    Tokarczyk, Anna; Rivens, Ian; van Bavel, E.; Symonds-Tayler, Richard; ter Haar, Gail

    2013-01-01

    An experimental system designed for the study of the effects of diagnostic or therapeutic ultrasound exposure on isolated blood vessels in the presence or absence of intraluminal contrast agent is described. The system comprised several components. A microscope was used to monitor vessel size (and

  20. Diffusion-weighted imaging and dynamic contrast-enhanced MRI of experimental breast cancer bone metastases – A correlation study with histology

    Energy Technology Data Exchange (ETDEWEB)

    Merz, Maximilian [Department of Medical Physics in Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Department of Hematology, Oncology and Rheumatology, Heidelberg University Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg (Germany); Seyler, Lisa; Bretschi, Maren; Semmler, Wolfhard [Department of Medical Physics in Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Bäuerle, Tobias, E-mail: tobias.baeuerle@uk-erlangen.de [Department of Medical Physics in Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Institute of Radiology, University Medical Center Erlangen, Palmsanlage 5, 90154 Erlangen (Germany)

    2015-04-15

    Purpose: To validate imaging parameters from diffusion-weighted imaging and dynamic contrast-enhanced MRI with immunohistology and to non-invasively assess microstructure of experimental breast cancer bone metastases. Materials and methods: Animals bearing breast cancer bone metastases were imaged in a clinical 1.5 T MRI scanner. HASTE sequences were performed to calculate apparent diffusion coefficients. Saturation recovery turbo FLASH sequences were conducted while infusing 0.1 mmol/l Gd–DTPA for dynamic contrast-enhanced MRI to quantify parameters amplitude A and exchange rate constant k{sub ep}. After imaging, bone metastases were analyzed immunohistologically. Results: We found correlations of the apparent diffusion coefficients from diffusion-weighted imaging with tumor cellularity as assessed with cell nuclei staining. Histological vessel maturity was correlated negatively with parameters A and k{sub ep} from dynamic contrast-enhanced MRI. Tumor size correlated inversely with cell density and vessel permeability as well as positively with mean vessel calibers. Parameters from the rim of bone metastases differed significantly from values of the center. Conclusion: In vivo diffusion-weighted imaging and dynamic contrast-enhanced MRI in experimental bone metastases provide information about tumor cellularity and vascularity and correlate well with immunohistology.

  1. Summary of Reported Whale-Vessel Collisions in Alaskan Waters

    Directory of Open Access Journals (Sweden)

    Janet L. Neilson

    2012-01-01

    Full Text Available Here we summarize 108 reported whale-vessel collisions in Alaska from 1978–2011, of which 25 are known to have resulted in the whale's death. We found 89 definite and 19 possible/probable strikes based on standard criteria we created for this study. Most strikes involved humpback whales (86% with six other species documented. Small vessel strikes were most common (<15 m, 60%, but medium (15–79 m, 27% and large (≥80 m, 13% vessels also struck whales. Among the 25 mortalities, vessel length was known in seven cases (190–294 m and vessel speed was known in three cases (12–19 kn. In 36 cases, human injury or property damage resulted from the collision, and at least 15 people were thrown into the water. In 15 cases humpback whales struck anchored or drifting vessels, suggesting the whales did not detect the vessels. Documenting collisions in Alaska will remain challenging due to remoteness and resource limitations. For a better understanding of the factors contributing to lethal collisions, we recommend (1 systematic documentation of collisions, including vessel size and speed; (2 greater efforts to necropsy stranded whales; (3 using experienced teams focused on determining cause of death; (4 using standard criteria for validating collision reports, such as those presented in this paper.

  2. Diffusion weighted MR imaging of transient ischemic attacks

    International Nuclear Information System (INIS)

    Chung, Jin Il; Kim, Dong Ik; Lee, Seung Ik; Yoon, Pyung Ho; Heo, Ji Hoe; Lee, Byung In

    2000-01-01

    To investigate the findings of diffusion-weighted MR imaging in patients with transient ischemic attacks (TIA). Between August 1996 and June 1999, 41 TIA patients (M:F =3D 28:13, mean age 57 (range, 27-75) years) with neurologic symptoms lasting less than 24 hours underwent diffusion-weighted MR imaging. The time interval between the onset of symptoms and MR examination was less than one week in 29 patients, from one week to one month in eight, and undetermined in four. Conventional MR and DWI were compared in terms of location of infarction and lesion size (less than 1 cm, 1-3 cm, greater than 3 cm), and we also determined the anatomical vascular territory of acute stroke lesions and possible etiologic mechanisms. The findings of DWI were normal in 24/41 patients (58.5%), while 15 (36.6%) showed acute ischemic lesions. The other two showed old lacunar infarcts. All acute and old DWI lesions were revealed by conventional MR imaging. Among the 15 acute stroke patients, seven had small vessel lacunar disease. In three patients, the infarction was less than 1 cm in size. Six patients showed large vessel infarction in the territory of the MCA, PCA, and PICA; the size of this was less than 1 cm in three patients, 1-3 cm in two, and more than 3 cm in one. In two patients, embolic infarction of cardiac origin in the territory of the MCA and AICA was diagnosed. The possible mechanism of TIA is still undetermined, but acute lesions revealed by DWI in TIA patients tend, in any case, to be small and multiple. (author)

  3. Integral reactor vessel related to power reactor safety

    International Nuclear Information System (INIS)

    Widart, J.; Scailteur, A.

    1978-01-01

    Integral design applied to PWR pressure vessels allows to reach a high level of safety because: 1) it presents a better balance of the material in the geometry, resulting in an improved stress level (mainly faulted condition loadings); 2) location and geometry of the welds are designed in order to get a very sound pressure boundary of the upper part of the vessel; 3) the new location and geometry of the welds allow an easy ISI in such a way that ambiguity surrounding defect size or locaton is practically suppressed. (author)

  4. Automated tracking and quantification of angiogenic vessel formation in 3D microfluidic devices.

    Science.gov (United States)

    Wang, Mengmeng; Ong, Lee-Ling Sharon; Dauwels, Justin; Asada, H Harry

    2017-01-01

    Angiogenesis, the growth of new blood vessels from pre-existing vessels, is a critical step in cancer invasion. Better understanding of the angiogenic mechanisms is required to develop effective antiangiogenic therapies for cancer treatment. We culture angiogenic vessels in 3D microfluidic devices under different Sphingosin-1-phosphate (S1P) conditions and develop an automated vessel formation tracking system (AVFTS) to track the angiogenic vessel formation and extract quantitative vessel information from the experimental time-lapse phase contrast images. The proposed AVFTS first preprocesses the experimental images, then applies a distance transform and an augmented fast marching method in skeletonization, and finally implements the Hungarian method in branch tracking. When applying the AVFTS to our experimental data, we achieve 97.3% precision and 93.9% recall by comparing with the ground truth obtained from manual tracking by visual inspection. This system enables biologists to quantitatively compare the influence of different growth factors. Specifically, we conclude that the positive S1P gradient increases cell migration and vessel elongation, leading to a higher probability for branching to occur. The AVFTS is also applicable to distinguish tip and stalk cells by considering the relative cell locations in a branch. Moreover, we generate a novel type of cell lineage plot, which not only provides cell migration and proliferation histories but also demonstrates cell phenotypic changes and branch information.

  5. Feature-size dependent selective edge enhancement of x-ray images

    International Nuclear Information System (INIS)

    Herman, S.

    1988-01-01

    Morphological filters are nonlinear signal transformations that operate on a picture directly in the space domain. Such filters are based on the theory of mathematical morphology previously formulated. The filt4er being presented here features a ''mask'' operator (called a ''structuring element'' in some of the literature) which is a function of the two spatial coordinates x and y. The two basic mathematical operations are called ''masked erosion'' and ''masked dilation''. In the case of masked erosion the mask is passed over the input image in a raster pattern. At each position of the mask, the pixel values under the mask are multiplied by the mask pixel values. Then the output pixel value, located at the center position of the mask,is set equal to the minimum of the product of the mask and input values. Similarity, for masked dilation, the output pixel value is the maximum of the product of the input and the mask pixel values. The two basic processes of dilation and erosion can be used to construct the next level of operations the ''positive sieve'' (also called ''opening'') and the ''negative sieve'' (''closing''). The positive sieve modifies the peaks in the image whereas the negative sieve works on image valleys. The positive sieve is implemented by passing the output of the masked erosion step through the masked dilation function. The negative sieve reverses this procedure, using a dilation followed by an erosion. Each such sifting operator is characterized by a ''hole size''. It will be shown that the choice of hole size will select the range of pixel detail sizes which are to be enhanced. The shape of the mask will govern the shape of the enhancement. Finally positive sifting is used to enhance positive-going (peak) features, whereas negative enhances the negative-going (valley) landmarks

  6. Association between different phases of menstrual cycle and body image measures of perceived size, ideal size, and body dissatisfaction.

    Science.gov (United States)

    Teixeira, André Luiz S; Dias, Marcelo Ricardo C; Damasceno, Vinícius O; Lamounier, Joel A; Gardner, Rick M

    2013-12-01

    The association between phases of the menstrual cycle and body image was investigated. 44 university women (M age = 23.3 yr., SD = 4.7) judged their perceived and ideal body size, and body dissatisfaction was calculated at each phase of the menstrual cycle, including premenstrual, menstrual, and intermenstrual. Participants selected one of nine figural drawings ranging from very thin to obese that represented their perceived size and ideal size. Body dissatisfaction was measured as the absolute difference between scores on perceived and ideal figural drawings. During each menstrual phase, anthropometric measures of weight, height, body mass index, circumference of waist and abdomen, and body composition were taken. There were no significant differences in any anthropometric measures between the three menstrual cycle phases. Perceived body size and body dissatisfaction were significantly different between menstrual phases, with the largest perceived body size and highest body dissatisfaction occurring during the menstrual phase. Ideal body size did not differ between menstrual phases, although participants desired a significantly smaller ideal size as compared to the perceived size.

  7. Reliability of fish size estimates obtained from multibeam imaging sonar

    Science.gov (United States)

    Hightower, Joseph E.; Magowan, Kevin J.; Brown, Lori M.; Fox, Dewayne A.

    2013-01-01

    Multibeam imaging sonars have considerable potential for use in fisheries surveys because the video-like images are easy to interpret, and they contain information about fish size, shape, and swimming behavior, as well as characteristics of occupied habitats. We examined images obtained using a dual-frequency identification sonar (DIDSON) multibeam sonar for Atlantic sturgeon Acipenser oxyrinchus oxyrinchus, striped bass Morone saxatilis, white perch M. americana, and channel catfish Ictalurus punctatus of known size (20–141 cm) to determine the reliability of length estimates. For ranges up to 11 m, percent measurement error (sonar estimate – total length)/total length × 100 varied by species but was not related to the fish's range or aspect angle (orientation relative to the sonar beam). Least-square mean percent error was significantly different from 0.0 for Atlantic sturgeon (x̄  =  −8.34, SE  =  2.39) and white perch (x̄  = 14.48, SE  =  3.99) but not striped bass (x̄  =  3.71, SE  =  2.58) or channel catfish (x̄  = 3.97, SE  =  5.16). Underestimating lengths of Atlantic sturgeon may be due to difficulty in detecting the snout or the longer dorsal lobe of the heterocercal tail. White perch was the smallest species tested, and it had the largest percent measurement errors (both positive and negative) and the lowest percentage of images classified as good or acceptable. Automated length estimates for the four species using Echoview software varied with position in the view-field. Estimates tended to be low at more extreme azimuthal angles (fish's angle off-axis within the view-field), but mean and maximum estimates were highly correlated with total length. Software estimates also were biased by fish images partially outside the view-field and when acoustic crosstalk occurred (when a fish perpendicular to the sonar and at relatively close range is detected in the side lobes of adjacent beams). These sources of

  8. Deformable 4DCT lung registration with vessel bifurcations

    International Nuclear Information System (INIS)

    Hilsmann, A.; Vik, T.; Kaus, M.; Franks, K.; Bissonette, J.P.; Purdie, T.; Beziak, A.; Aach, T.

    2007-01-01

    In radiotherapy planning of lung cancer, breathing motion causes uncertainty in the determination of the target volume. Image registration makes it possible to get information about the deformation of the lung and the tumor movement in the respiratory cycle from a few images. A dedicated, automatic, landmark-based technique was developed that finds corresponding vessel bifurcations. Hereby, we developed criteria to characterize pronounced bifurcations for which correspondence finding was more stable and accurate. The bifurcations were extracted from automatically segmented vessel trees in maximum inhale and maximum exhale CT thorax data sets. To find corresponding bifurcations in both data sets we used the shape context approach of Belongie et al. Finally, a volumetric lung deformation was obtained using thin-plate spline interpolation and affine registration. The method is evaluated on 10 4D-CT data sets of patients with lung cancer. (orig.)

  9. A Review of Algorithms for Retinal Vessel Segmentation

    Directory of Open Access Journals (Sweden)

    Monserrate Intriago Pazmiño

    2014-10-01

    Full Text Available This paper presents a review of algorithms for extracting blood vessels network from retinal images. Since retina is a complex and delicate ocular structure, a huge effort in computer vision is devoted to study blood vessels network for helping the diagnosis of pathologies like diabetic retinopathy, hypertension retinopathy, retinopathy of prematurity or glaucoma. To carry out this process many works for normal and abnormal images have been proposed recently. These methods include combinations of algorithms like Gaussian and Gabor filters, histogram equalization, clustering, binarization, motion contrast, matched filters, combined corner/edge detectors, multi-scale line operators, neural networks, ants, genetic algorithms, morphological operators. To apply these algorithms pre-processing tasks are needed. Most of these algorithms have been tested on publicly retinal databases. We have include a table summarizing algorithms and results of their assessment.

  10. A 481-year chronology of oak earlywood vessels as an age-independent climatic proxy in NW Iberia

    Science.gov (United States)

    Souto-Herrero, Manuel; Rozas, Vicente; García-González, Ignacio

    2017-08-01

    The earlywood vessels of ring-porous trees can be analyzed dendrochronologically and used as a proxy for environmental information. However, most works deal with the analysis of contemporary climate-growth relationships and do not evaluate their long-term variation. We obtained a 481-year chronology of earlywood vessel size of oak (Quercus robur L.) in the northwestern Iberian Peninsula, investigated its behavior through time, and compared it to a chronology of younger trees developed at the same site. We expressed earlywood vessel size as the hydraulically-weighted diameter (DH) and discriminated between vessels in the first row (r1) and the rest of the vessels (nr1); radial increment was assessed from latewood width (LW). Climate-growth relationships were strong and nearly identical for both age classes. Spring temperature positively affected vessel size, but only for the first row, probably mediating the onset of cambial activity. The chronology of old trees showed an almost flat age trend, except for the first decades, and series were not affected by stand dynamics. In contrast, LW had a weak response to climate, probably because of the high impact of abrupt growth changes. There was a high negative correlation between DH and the winter North Atlantic Oscillation Index (NAO), which was unstable during the 20th century. To our knowledge, this is the longest chronology of earlywood vessel size obtained to date, and offers promising results, as this proxy is shown to be independent of age and forest disturbances, and was strongly correlated to climate across long time spans.

  11. ROSA-V/LSTF vessel top head LOCA tests SB-PV-07 and SB-PV-08 with break sizes of 1.0 and 0.1% and operator recovery actions for core cooling

    International Nuclear Information System (INIS)

    Suzuki, Mitsuhiro; Takeda, Takeshi; Nakamura, Hideo

    2010-02-01

    A series of break size parameter tests (SB-PV-07 and SB-PV-08) were conducted at the Large Scale Test Facility (LSTF) of ROSA-V Program by simulating a vessel top small break loss-of-coolant accident (SBLOCA) at a pressurized water reactor (PWR). Typical phenomena to the vessel top break LOCA and effectiveness of operator recovery actions on core cooling were studied under an assumption of total failure of high pressure injection (HPI) system. The LSTF simulates a 4-loop 3423 MWt PWR by a full-height, full-pressure and 1/48 volume scaling two-loop system. Typical phenomena of vessel top break LOCA are clarified for the cases with break sizes of 1.0 and 0.1% cold leg break equivalent. The results from a 0.5% top break LOCA test (SB-PV-02) in the early ROSA-IV Program was referred during discussion. Operator actions of HPI recovery in the 1.0% top break test and steam generator (SG) depressurization in the 0.1% top break test were initiated when temperature at core exit thermocouple (CET) reached 623 K during core boil-off. Both operator actions resulted in immediate recovery of core cooling. Based on the obtained data, several thermal-hydraulic phenomena were discussed further such as relations between vessel top head water level and steam discharge at the break, and between coolant mass inventory transient and core heat-up and quench behavior, and CET performances to detect core heat-up under influences of three-dimensional (3D) steam flows in the core and core exit. (author)

  12. Open vessel microwave digestion of food matrices (T6)

    International Nuclear Information System (INIS)

    Rhodes, L.; LeBlanc, G.

    2002-01-01

    Full text: Advancements in the field of open vessel microwave digestion continue to provide solutions for industries requiring acid digestion of large sample sizes. Those interesting in digesting food matrices are particularly interested in working with large amounts of sample and then diluting small final volumes. This paper will show the advantages of instantaneous regent addition and post-digestion evaporation when performing an open vessel digestion and evaporation methods for various food matrices will be presented along with analyte recovery data. (author)

  13. A Fovea Localization Scheme Using Vessel Origin-Based Parabolic Model

    Directory of Open Access Journals (Sweden)

    Chun-Yuan Yu

    2014-09-01

    Full Text Available At the center of the macula, fovea plays an important role in computer-aided diagnosis. To locate the fovea, this paper proposes a vessel origin (VO-based parabolic model, which takes the VO as the vertex of the parabola-like vasculature. Image processing steps are applied to accurately locate the fovea on retinal images. Firstly, morphological gradient and the circular Hough transform are used to find the optic disc. The structure of the vessel is then segmented with the line detector. Based on the characteristics of the VO, four features of VO are extracted, following the Bayesian classification procedure. Once the VO is identified, the VO-based parabolic model will locate the fovea. To find the fittest parabola and the symmetry axis of the retinal vessel, an Shift and Rotation (SR-Hough transform that combines the Hough transform with the shift and rotation of coordinates is presented. Two public databases of retinal images, DRIVE and STARE, are used to evaluate the proposed method. The experiment results show that the average Euclidean distances between the located fovea and the fovea marked by experts in two databases are 9.8 pixels and 30.7 pixels, respectively. The results are stronger than other methods and thus provide a better macular detection for further disease discovery.

  14. My 'Fat Girl Complex': a preliminary investigation of sexual health and body image in women of size.

    Science.gov (United States)

    Satinsky, Sonya; Dennis, Barbara; Reece, Michael; Sanders, Stephanie; Bardzell, Shaowen

    2013-01-01

    Women of size who inhabit non-normative bodies may have different experiences with body image and sexual health than women of average body size. In this exploratory study, we interviewed four women of size recruited from a larger mixed-methodological study of body image and sexuality. Each woman was interviewed twice on topics of body image, sexuality and sexual health. Reconstructive Horizon Analysis was used to analyse the content of the interviews. Women who expressed that their bodies had inherent personal and social value regardless of size did not articulate connections between body size and their sexual health. However, those women who looked externally for validation of their attractiveness struggled with acceptance of their sexuality and bodies and spoke of ways in which their body size and appearance hindered them from having the sexually healthy lives that they wanted. Findings highlight two important components of women's sexual health as participants related them to body image: the right to pleasure and the right to engage only in wanted sexual activity. Participants described how negative body attitudes affected both of these aspects of their sexual health. Interventions targeting weight-based stigma may offer a means of indirectly promoting sexual health and autonomy in women.

  15. Primo vessel inside a lymph vessel emerging from a cancer tissue.

    Science.gov (United States)

    Lee, Sungwoo; Ryu, Yeonhee; Cha, Jinmyung; Lee, Jin-Kyu; Soh, Kwang-Sup; Kim, Sungchul; Lim, Jaekwan

    2012-10-01

    Primo vessels were observed inside the lymph vessels near the caudal vena cava of a rabbit and a rat and in the thoracic lymph duct of a mouse. In the current work we found a primo vessel inside the lymph vessel that came out from the tumor tissue of a mouse. A cancer model of a nude mouse was made with human lung cancer cell line NCI-H460. We injected fluorescent nanoparticles into the xenografted tumor tissue and studied their flow in blood, lymph, and primo vessels. Fluorescent nanoparticles flowed through the blood vessels quickly in few minutes, and but slowly in the lymph vessels. The bright fluorescent signals of nanoparticles disappeared within one hour in the blood vessels but remained much longer up to several hours in the case of lymph vessels. We found an exceptional case of lymph vessels that remained bright with fluorescence up to 24 hours. After detailed examination we found that the bright fluorescence was due to a putative primo vessel inside the lymph vessel. This rare observation is consistent with Bong-Han Kim's claim on the presence of a primo vascular system in lymph vessels. It provides a significant suggestion on the cancer metastasis through primo vessels and lymph vessels. Copyright © 2012. Published by Elsevier B.V.

  16. The best of a BAD situation: Optimising an algorithm to match course resolution SAR vessel detections to sparse AIS data

    CSIR Research Space (South Africa)

    Meyer, Rory GV

    2017-07-01

    Full Text Available The detection and classification of SAR imaged vessels at sea is a valuable ability for organisations interested in the marine environment or marine vessels. Matching the SAR detected vessels to their AIS messages allows vessels to be identified...

  17. SIZE OF BOEHMITE NANOPARTICLES BY TEM IMAGES ANALYSIS

    Directory of Open Access Journals (Sweden)

    Maxime Moreaud

    2011-05-01

    Full Text Available Transition aluminas, and especially the gamma type, are largely used as catalyst supports in refining and petrochemicals. Most studies focus on properties resulting from material texture and casting (specific surface, porous volume, pore shape and diameter. However, surface properties of alumina should be considered as well, as the catalytic activity is tightly related to the structure of exposed crystalline faces. As γ alumina results from controlled thermal treatment of boehmite γ-AlOOH by a topotactic transformation, the nature of exposed crystalline planes is related to the starting material. Therefore, the synthesis of the oxihydroxide γ-AlOOH, and especially size and shape of these particles, is critical in determining the relevant surface properties. Unlike often aggregated alumina, boehmite nanoparticles can be observed by TEM. Analysis of these TEM images can be performed to estimate the size of the boehmite nanoparticles. Information about morphology of the nanoparticles is obtained by the analysis of the covariance, modeling micrographs by a dilution model.

  18. Collateral vessels in moyamoya disease : comparison of MR and MRA with conventional angiography

    International Nuclear Information System (INIS)

    Shim, Joo Eun; Yoon, Dae Young; Yi, Jeong Geun; Kim, Ho Chul; Choi, Chul Sun; Bae, Sang Hoon

    1998-01-01

    To determine the value of magnetic resonance imaging (MR) and magnetic resonance angiography (MRA) in assessing collateral vessels of moyamoya disease. Twenty-four patients with moyamoya disease who underwent MR, 3D TOF MRA, and conventional angiography participated in this study. Two radiologists working independently and with no knowledge of the angiographic findings, interpreted the MR and MRA images. To determine the presence of parenchymal and leptomeningeal collaterals (48 hemispheres) and transdural collaterals (38 hemispheres in 19 patients were depicted by angiography of the external carotid), the findings were compared with those of angiography. Parenchymal, leptomeningeal, and transdural collaterals were depicted by conventional angiography in 34 (71%), 32 (67%), and 11 (29%) hemispheres respectively. The sensitivity and specificity of MR/MRA for collateral vessels were 79.1/88.1 % for parenchymal collaterals, 72.1/88.1 % for leptomeningeal collaterals, and 0.1/18.1 % for transdural collaterals, respectively. Respective sensitivity and specificity of MR/MRA were 88.94/94.1% for leptomeningeal collaterals, and 18.93/55.1 % for transdural collaterals, when the prominent posterior cerebral and external carotid artery were regarded as secondary signs of leptomeningeal and transdural collateral vessels. In moyamoya disease, MR and MRA are useful imaging modalities for the assessment of collateral vessels. The prominent posterior cerebral artery and external carotid artery can be useful secondary signs of leptomeningeal and transdural collateral vessels. (author). 18 refs., 2 figs

  19. Reconstruction of vessel structures from serial whole slide sections of murine liver samples

    Science.gov (United States)

    Schwier, Michael; Hahn, Horst K.; Dahmen, Uta; Dirsch, Olaf

    2013-03-01

    Image-based analysis of the vascular structures of murine liver samples is an important tool for scientists to understand liver physiology and morphology. Typical assessment methods are MicroCT, which allows for acquiring images of the whole organ while lacking resolution for fine details, and confocal laser scanning microscopy, which allows detailed insights into fine structures while lacking the broader context. Imaging of histological serial whole slide sections is a recent technology able to fill this gap, since it provides a fine resolution up to the cellular level, but on a whole organ scale. However, whole slide imaging is a modality providing only 2D images. Therefore the challenge is to use stacks of serial sections from which to reconstruct the 3D vessel structures. In this paper we present a semi-automatic procedure to achieve this goal. We employ an automatic method that detects vessel structures based on continuity and shape characteristics. Furthermore it supports the user to perform manual corrections where required. With our methods we were able to successfully extract and reconstruct vessel structures from a stack of 100 and a stack of 397 serial sections of a mouse liver lobe, thus proving the potential of our approach.

  20. Studying time of flight imaging through scattering media across multiple size scales (Conference Presentation)

    Science.gov (United States)

    Velten, Andreas

    2017-05-01

    Light scattering is a primary obstacle to optical imaging in a variety of different environments and across many size and time scales. Scattering complicates imaging on large scales when imaging through the atmosphere when imaging from airborne or space borne platforms, through marine fog, or through fog and dust in vehicle navigation, for example in self driving cars. On smaller scales, scattering is the major obstacle when imaging through human tissue in biomedical applications. Despite the large variety of participating materials and size scales, light transport in all these environments is usually described with very similar scattering models that are defined by the same small set of parameters, including scattering and absorption length and phase function. We attempt a study of scattering and methods of imaging through scattering across different scales and media, particularly with respect to the use of time of flight information. We can show that using time of flight, in addition to spatial information, provides distinct advantages in scattering environments. By performing a comparative study of scattering across scales and media, we are able to suggest scale models for scattering environments to aid lab research. We also can transfer knowledge and methodology between different fields.

  1. Cerebral arteriovenous malformations. the relationship between clinical related events and rCBF SPECT imaging

    International Nuclear Information System (INIS)

    Sun Bo; Shi Xiangen

    1996-01-01

    To evaluate the relationship between clinical related events and rCBF SPECT imaging in patients with arteriovenous malformations (AVMs), the radioactive counting difference between normal and lesion site was divided by regional pixel considered as ischemic index (II). II was measured in 20 AVM cases and compared with patients' age, sex,neurological history and the size of lesions. The degree of rCBF reduction correlated with clinical neurological manifestation and showed no significant relationship with the age, sex and size of malformed vessels. II in patients with seizures was higher than that in patients with hemorrhage. The rCBF SPECT imaging may be useful for evaluation of the hemodynamics in AVMs

  2. Development of Ultrasonic Visual Inspection Program for In-Vessel Structures of SFR

    International Nuclear Information System (INIS)

    Joo, Y. S.; Park, C. G.; Lee, J. H.

    2009-02-01

    As the liquid sodium of a sodium-cooled fast reactor (SFR) is opaque to light, a conventional visual inspection is unavailable for the evaluation of the in-vessel structures under a sodium level. ASME Section XI Division 3 provides rules and guidelines for an in-service inspection (ISI) and testing of the components of SFR. For the ISI of in-vessel structures, the ASME code specifies visual examinations. An ultrasonic wave should be applied for an under-sodium visual inspection of the in-vessel structures. The plate-type waveguide sensor has been developed and the feasibility of the waveguide sensor technique has been successfully demonstrated for an ultrasonic visual inspection of the in-vessel structures of SFR. In this study, the C-scan image mapping program (Under-Sodium MultiView) is developed to apply this waveguide sensor technology to an under-sodium visual inspection of in-vessel structures in SFR by using a LabVIEW graphical programming language. The Under-Sodium MultiVIEW program has the functions of a double rotating scanner motion control, a high power pulser receiver control, a image mapping and a signal processing. The performance of Under-Sodium MultiVIEW program was verified by a C-scanning test

  3. Novel method for edge detection of retinal vessels based on the model of the retinal vascular network and mathematical morphology

    Science.gov (United States)

    Xu, Lei; Zheng, Xiaoxiang; Zhang, Hengyi; Yu, Yajun

    1998-09-01

    Accurate edge detection of retinal vessels is a prerequisite for quantitative analysis of subtle morphological changes of retinal vessels under different pathological conditions. A novel method for edge detection of retinal vessels is presented in this paper. Methods: (1) Wavelet-based image preprocessing. (2) The signed edge detection algorithm and mathematical morphological operation are applied to get the approximate regions that contain retinal vessels. (3) By convolving the preprocessed image with a LoG operator only on the detected approximate regions of retinal vessels, followed by edges refining, clear edge maps of the retinal vessels are fast obtained. Results: A detailed performance evaluation together with the existing techniques is given to demonstrate the strong features of our method. Conclusions: True edge locations of retinal vessels can be fast detected with continuous structures of retinal vessels, less non- vessel segments left and insensitivity to noise. The method is also suitable for other application fields such as road edge detection.

  4. Structural design and manufacturing of TPE-RX vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Sago, H.; Orita, J.; Kaguchi, H.; Ishigami, Y. [Mitsubishi Heavy Ind. Ltd., Kobe (Japan); Urata, K.; Kudough, F. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan); Hasegawa, M.; Oyabu, I. [Mitsubishi Electric Co., Tokyo (Japan); Yagi, Y.; Sekine, S.; Shimada, T.; Hirano, Y.; Sakakita, H.; Koguchi, H. [Electrotechnical Laboratory, Tsukuba (Japan)

    1999-10-01

    TPE-RX is a newly constructed, large-sized reversed field pinch (RFP) machine installed at the Electrotechnical Laboratory of the Ministry of International Trade and Industry in Japan. This is the third largest RFP in the world. Major and minor radii of the plasma are 1.72 and 0.45 m, respectively. TPE-RX aims to optimize plasma confinement up to 1 MA. RFP plasma configuration was successfully obtained in March 1998. This paper reports the structural design and manufacturing of the vacuum vessel of TPE-RX. The supporting system on the bellows sections of the vessel was designed based on a detailed finite element method. The integrity of the vacuum vessel against a plasma disruption has been confirmed using dynamic inelastic analyses. (orig.)

  5. Structural design and manufacturing of TPE-RX vacuum vessel

    International Nuclear Information System (INIS)

    Sago, H.; Orita, J.; Kaguchi, H.; Ishigami, Y.; Urata, K.; Kudough, F.; Hasegawa, M.; Oyabu, I.; Yagi, Y.; Sekine, S.; Shimada, T.; Hirano, Y.; Sakakita, H.; Koguchi, H.

    1999-01-01

    TPE-RX is a newly constructed, large-sized reversed field pinch (RFP) machine installed at the Electrotechnical Laboratory of the Ministry of International Trade and Industry in Japan. This is the third largest RFP in the world. Major and minor radii of the plasma are 1.72 and 0.45 m, respectively. TPE-RX aims to optimize plasma confinement up to 1 MA. RFP plasma configuration was successfully obtained in March 1998. This paper reports the structural design and manufacturing of the vacuum vessel of TPE-RX. The supporting system on the bellows sections of the vessel was designed based on a detailed finite element method. The integrity of the vacuum vessel against a plasma disruption has been confirmed using dynamic inelastic analyses. (orig.)

  6. Modified ITER In-Vessel Viewing System

    International Nuclear Information System (INIS)

    Ahola, H.; Heikkinen, V.; Keraenen, K.; Suomela, J.

    2001-01-01

    The original ITER In-Vessel Viewing System (IVVS) prototype (Proc. of the 20th SOFT, vol. 2 (1998) 1051), which demonstrates the feasibility of linear fibre arrays for ITER in-vessel viewing, has been modified. In order to reduce the viewing time and to improve the image quality the beam dispersing mirrors was replaced by a diffractive optics element (DOE), which enhanced the laser illumination considerably. The performance of the system was tested using various target surfaces: the results obtained clearly indicate its adequacy for in-vessel viewing. Mechanical damage on smooth metal surfaces (scratches etc.) can be easily distinguished and the viewing resolution at a distance of 2 m is better than 1 mm. The IVVS has been re-designed to be compatible with the new ITER-FEAT. A conceptual study which covers all the functions and subsystems required for viewing has been completed. These results will be used to further modify the prototype: items to be tested include horizontal probe operation and laser illumination with an optical fibre

  7. Analytical modeling of the effect of crack depth, specimen size, and biaxial stress on the fracture toughness of reactor vessel steels

    International Nuclear Information System (INIS)

    Chao, Yuh-Jin

    1995-01-01

    Fracture, toughness values for A533-B reactor pressure vessel (RPV) steel obtained from test programs at Oak Ridge National Laboratory (ORNL) and University of Kansas (KU) are interpreted using the J-A 2 analytical model. The analytical model is based on the critical stress concept and takes into consideration the constraint effect using the second parameter A 2 in addition to the generally accepted first parameter J which represents the loading level. It is demonstrated that with the constraint level included in the model effects of crack depth (shallow vs deep), specimen size (small vs. large), and loading type (uniaxial vs biaxial) on the fracture toughness from the test programs can be interpreted and predicted

  8. Design and implementation of visual inspection system handed in tokamak flexible in-vessel robot

    International Nuclear Information System (INIS)

    Wang, Hesheng; Xu, Lifei; Chen, Weidong

    2016-01-01

    In-vessel viewing system (IVVS) is a fundamental tool among the remote handling systems for ITER, which is used to providing information on the status of the in-vessel components. The basic functional requirement of in-vessel visual inspection system is to perform a fast intervention with adequate optical resolution. In this paper, we present the software and hardware solution, which is designed and implemented for tokamak in-vessel viewing system that installed on end-effector of flexible in-vessel robot working under vacuum and high temperature. The characteristic of our in-vessel viewing system consists of two parts: binocular heterogeneous vision inspection tool and first wall scene emersion based augment virtuality. The former protected with water-cooled shield is designed to satisfy the basic functional requirement of visual inspection system, which has the capacity of large field of view and high-resolution for detection precision. The latter, achieved by overlaying first wall tiles images onto virtual first wall scene model in 3D virtual reality simulation system, is designed for convenient, intuitive and realistic-looking visual inspection instead of viewing the status of first wall only by real-time monitoring or off-line images sequences. We present the modular division of system, each of them in smaller detail, and go through some of the design choices according to requirements of in-vessel visual inspection task.

  9. Design and implementation of visual inspection system handed in tokamak flexible in-vessel robot

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hesheng; Xu, Lifei [Department of Automation, Shanghai Jiao Tong University, Shanghai 200240 (China); Key Laboratory of System Control and Information Processing, Ministry of Education of China (China); Chen, Weidong, E-mail: wdchen@sjtu.edu.cn [Department of Automation, Shanghai Jiao Tong University, Shanghai 200240 (China); Key Laboratory of System Control and Information Processing, Ministry of Education of China (China)

    2016-05-15

    In-vessel viewing system (IVVS) is a fundamental tool among the remote handling systems for ITER, which is used to providing information on the status of the in-vessel components. The basic functional requirement of in-vessel visual inspection system is to perform a fast intervention with adequate optical resolution. In this paper, we present the software and hardware solution, which is designed and implemented for tokamak in-vessel viewing system that installed on end-effector of flexible in-vessel robot working under vacuum and high temperature. The characteristic of our in-vessel viewing system consists of two parts: binocular heterogeneous vision inspection tool and first wall scene emersion based augment virtuality. The former protected with water-cooled shield is designed to satisfy the basic functional requirement of visual inspection system, which has the capacity of large field of view and high-resolution for detection precision. The latter, achieved by overlaying first wall tiles images onto virtual first wall scene model in 3D virtual reality simulation system, is designed for convenient, intuitive and realistic-looking visual inspection instead of viewing the status of first wall only by real-time monitoring or off-line images sequences. We present the modular division of system, each of them in smaller detail, and go through some of the design choices according to requirements of in-vessel visual inspection task.

  10. Arctic research vessel design would expand science prospects

    Science.gov (United States)

    Elsner, Robert; Kristensen, Dirk

    The U.S. polar marine science community has long declared the need for an arctic research vessel dedicated to advancing the study of northern ice-dominated seas. Planning for such a vessel began 2 decades ago, but competition for funding has prevented construction. A new design program is underway, and it shows promise of opening up exciting possibilities for new research initiatives in arctic marine science.With its latest design, the Arctic Research Vessel (ARV) has grown to a size and capability that will make it the first U.S. academic research vessel able to provide access to the Arctic Ocean. This ship would open a vast arena for new studies in the least known of the world's seas. These studies promise to rank high in national priority because of the importance of the Arctic Ocean as a source of data relating to global climate change. Other issues that demand attention in the Arctic include its contributions to the world's heat budget, the climate history buried in its sediments, pollution monitoring, and the influence of arctic conditions on marine renewable resources.

  11. [Small vessel cerebrovascular disease].

    Science.gov (United States)

    Cardona Portela, P; Escrig Avellaneda, A

    2018-05-09

    Small vessel vascular disease is a spectrum of different conditions that includes lacunar infarction, alteration of deep white matter, or microbleeds. Hypertension is the main risk factor, although the atherothrombotic lesion may be present, particularly in large-sized lacunar infarctions along with other vascular risk factors. MRI findings are characteristic and the lesions authentic biomarkers that allow differentiating the value of risk factors and defining their prognostic value. Copyright © 2018 SEH-LELHA. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. Clinical, angiographic, hemodynamic, perfusional and functional changes after one-vessel left anterior descending coronary angioplasty

    International Nuclear Information System (INIS)

    Okada, R.D.; Lim, Y.L.; Boucher, C.A.; Pohost, G.M.; Chesler, D.A.; Block, P.C.

    1985-01-01

    Percutaneous transluminal coronary angioplasty (PTCA) was successfully performed in 20 patients with 1-vessel left anterior descending (LAD) coronary artery disease. Exercise capacity in terms of peak workload, heart rate and systolic blood pressure all increased significantly 1 week after PTCA. All patients had some decrease in stenosis size and gradient. All patients except 1 had an improvement in functional class. Eight of 12 patients with abnormal exercise electrocardiograms before PTCA had normal electrocardiograms after the procedure. Exercise thallium-201 (TI-201) myocardial perfusion images obtained in all 20 patients before and 1 week after PTCA were analyzed using a new computer method designed to quantitate regional myocardial TI-201 distribution, redistribution and clearance rate. Significant improvement in TI-201 activity was present in the anterior and septal segments of the left ventricle 1 week after PTCA. This increase in TI-201 uptake was associated with a significant reduction in the amount of TI-201 redistribution between initial and delayed postexercise images in the same regions. TI-201 clearance rate in the segments supplied by the dilated vessel also improved significantly. Abnormal TI-201 lung uptake was seen in 17 patients before and in 4 patients after PTCA. Exercise ejection fraction response and septal wall motion also improved after PTCA of the LAD stenosis in all 17 patients who had exercise radionuclide ventriculography

  13. Statistical analysis of support thickness and particle size effects in HRTEM imaging of metal nanoparticles

    International Nuclear Information System (INIS)

    House, Stephen D.; Bonifacio, Cecile S.; Grieshaber, Ross V.; Li, Long; Zhang, Zhongfan; Ciston, Jim; Stach, Eric A.; Yang, Judith C.

    2016-01-01

    High-resolution transmission electron microscopy (HRTEM) examination of nanoparticles requires their placement on some manner of support – either TEM grid membranes or part of the material itself, as in many heterogeneous catalyst systems – but a systematic quantification of the practical imaging limits of this approach has been lacking. Here we address this issue through a statistical evaluation of how nanoparticle size and substrate thickness affects the ability to resolve structural features of interest in HRTEM images of metallic nanoparticles on common support membranes. The visibility of lattice fringes from crystalline Au nanoparticles on amorphous carbon and silicon supports of varying thickness was investigated with both conventional and aberration-corrected TEM. Over the 1–4 nm nanoparticle size range examined, the probability of successfully resolving lattice fringes differed significantly as a function both of nanoparticle size and support thickness. Statistical analysis was used to formulate guidelines for the selection of supports and to quantify the impact a given support would have on HRTEM imaging of crystalline structure. For nanoparticles ≥1 nm, aberration-correction was found to provide limited benefit for the purpose of visualizing lattice fringes; electron dose is more predictive of lattice fringe visibility than aberration correction. These results confirm that the ability to visualize lattice fringes is ultimately dependent on the signal-to-noise ratio of the HRTEM images, rather than the point-to-point resolving power of the microscope. This study provides a benchmark for HRTEM imaging of crystalline supported metal nanoparticles and is extensible to a wide variety of supports and nanostructures. - Highlights: • The impact of supports on imaging nanoparticle lattice structure is quantified. • Visualization probabilities given particle size and support thickness are estimated. • Aberration-correction provided limited benefit

  14. Statistical analysis of support thickness and particle size effects in HRTEM imaging of metal nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    House, Stephen D., E-mail: sdh46@pitt.edu [Chemical and Petroleum Engineering, and Physics, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Bonifacio, Cecile S.; Grieshaber, Ross V.; Li, Long; Zhang, Zhongfan [Chemical and Petroleum Engineering, and Physics, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Ciston, Jim [National Center of Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Stach, Eric A. [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973 (United States); Yang, Judith C. [Chemical and Petroleum Engineering, and Physics, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

    2016-10-15

    High-resolution transmission electron microscopy (HRTEM) examination of nanoparticles requires their placement on some manner of support – either TEM grid membranes or part of the material itself, as in many heterogeneous catalyst systems – but a systematic quantification of the practical imaging limits of this approach has been lacking. Here we address this issue through a statistical evaluation of how nanoparticle size and substrate thickness affects the ability to resolve structural features of interest in HRTEM images of metallic nanoparticles on common support membranes. The visibility of lattice fringes from crystalline Au nanoparticles on amorphous carbon and silicon supports of varying thickness was investigated with both conventional and aberration-corrected TEM. Over the 1–4 nm nanoparticle size range examined, the probability of successfully resolving lattice fringes differed significantly as a function both of nanoparticle size and support thickness. Statistical analysis was used to formulate guidelines for the selection of supports and to quantify the impact a given support would have on HRTEM imaging of crystalline structure. For nanoparticles ≥1 nm, aberration-correction was found to provide limited benefit for the purpose of visualizing lattice fringes; electron dose is more predictive of lattice fringe visibility than aberration correction. These results confirm that the ability to visualize lattice fringes is ultimately dependent on the signal-to-noise ratio of the HRTEM images, rather than the point-to-point resolving power of the microscope. This study provides a benchmark for HRTEM imaging of crystalline supported metal nanoparticles and is extensible to a wide variety of supports and nanostructures. - Highlights: • The impact of supports on imaging nanoparticle lattice structure is quantified. • Visualization probabilities given particle size and support thickness are estimated. • Aberration-correction provided limited benefit

  15. Captopril improves tumor nanomedicine delivery by increasing tumor blood perfusion and enlarging endothelial gaps in tumor blood vessels.

    Science.gov (United States)

    Zhang, Bo; Jiang, Ting; Tuo, Yanyan; Jin, Kai; Luo, Zimiao; Shi, Wei; Mei, Heng; Hu, Yu; Pang, Zhiqing; Jiang, Xinguo

    2017-12-01

    Poor tumor perfusion and unfavorable vessel permeability compromise nanomedicine drug delivery to tumors. Captopril dilates blood vessels, reducing blood pressure clinically and bradykinin, as the downstream signaling moiety of captopril, is capable of dilating blood vessels and effectively increasing vessel permeability. The hypothesis behind this study was that captopril can dilate tumor blood vessels, improving tumor perfusion and simultaneously enlarge the endothelial gaps of tumor vessels, therefore enhancing nanomedicine drug delivery for tumor therapy. Using the U87 tumor xenograft with abundant blood vessels as the tumor model, tumor perfusion experiments were carried out using laser Doppler imaging and lectin-labeling experiments. A single treatment of captopril at a dose of 100 mg/kg significantly increased the percentage of functional vessels in tumor tissues and improved tumor blood perfusion. Scanning electron microscopy of tumor vessels also indicated that the endothelial gaps of tumor vessels were enlarged after captopril treatment. Immunofluorescence-staining of tumor slices demonstrated that captopril significantly increased bradykinin expression, possibly explaining tumor perfusion improvements and endothelial gap enlargement. Additionally, imaging in vivo, imaging ex vivo and nanoparticle distribution in tumor slices indicated that after a single treatment with captopril, the accumulation of 115-nm nanoparticles in tumors had increased 2.81-fold with a more homogeneous distribution pattern in comparison to non-captopril treated controls. Finally, pharmacodynamics experiments demonstrated that captopril combined with paclitaxel-loaded nanoparticles resulted in the greatest tumor shrinkage and the most extensive necrosis in tumor tissues among all treatment groups. Taken together, the data from the present study suggest a novel strategy for improving tumor perfusion and enlarging blood vessel permeability simultaneously in order to improve

  16. Testing of VVER reactor pressure vessels by TOFD method

    International Nuclear Information System (INIS)

    Skala, Z.; Vit, J.

    2002-01-01

    The Time of Flight Diffraction Method (TOFD) - one of the new testing methods capable to obtain the real dimensions of flaws - is presented in the paper.The laboratory experiments on samples with artificial flaws and samples with artificially prepared cracks confirmed the high accuracy of flaw through wall extent sizing by TOFD. This accuracy was confirmed by qualification of methods and systems used by Skoda JS for the in-service inspections of WWER 440 vessel circumferential weld. The qualification also confirmed the ability of TOFD to detect reliably flaws, which can are not reliably detected by standard pulse echo testing. Based on the result of experiments and qualification, the TOFD method shall be used routinely by Skoda JS for the inspection of vessel circumferential welds root area and for sizing of flaws exceeding the acceptance level

  17. Dynamic stroma reorganization drives blood vessel dysmorphia during glioma growth.

    Science.gov (United States)

    Mathivet, Thomas; Bouleti, Claire; Van Woensel, Matthias; Stanchi, Fabio; Verschuere, Tina; Phng, Li-Kun; Dejaegher, Joost; Balcer, Marly; Matsumoto, Ken; Georgieva, Petya B; Belmans, Jochen; Sciot, Raf; Stockmann, Christian; Mazzone, Massimiliano; De Vleeschouwer, Steven; Gerhardt, Holger

    2017-12-01

    Glioma growth and progression are characterized by abundant development of blood vessels that are highly aberrant and poorly functional, with detrimental consequences for drug delivery efficacy. The mechanisms driving this vessel dysmorphia during tumor progression are poorly understood. Using longitudinal intravital imaging in a mouse glioma model, we identify that dynamic sprouting and functional morphogenesis of a highly branched vessel network characterize the initial tumor growth, dramatically changing to vessel expansion, leakage, and loss of branching complexity in the later stages. This vascular phenotype transition was accompanied by recruitment of predominantly pro-inflammatory M1-like macrophages in the early stages, followed by in situ repolarization to M2-like macrophages, which produced VEGF-A and relocate to perivascular areas. A similar enrichment and perivascular accumulation of M2 versus M1 macrophages correlated with vessel dilation and malignancy in human glioma samples of different WHO malignancy grade. Targeting macrophages using anti-CSF1 treatment restored normal blood vessel patterning and function. Combination treatment with chemotherapy showed survival benefit, suggesting that targeting macrophages as the key driver of blood vessel dysmorphia in glioma progression presents opportunities to improve efficacy of chemotherapeutic agents. We propose that vessel dysfunction is not simply a general feature of tumor vessel formation, but rather an emergent property resulting from a dynamic and functional reorganization of the tumor stroma and its angiogenic influences. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

  18. A preclinical Talbot-Lau prototype for x-ray dark-field imaging of human-sized objects.

    Science.gov (United States)

    Hauke, C; Bartl, P; Leghissa, M; Ritschl, L; Sutter, S M; Weber, T; Zeidler, J; Freudenberger, J; Mertelmeier, T; Radicke, M; Michel, T; Anton, G; Meinel, F G; Baehr, A; Auweter, S; Bondesson, D; Gaass, T; Dinkel, J; Reiser, M; Hellbach, K

    2018-03-26

    Talbot-Lau x-ray interferometry provides information about the scattering and refractive properties of an object - in addition to the object's attenuation features. Until recently, this method was ineligible for imaging human-sized objects as it is challenging to adapt Talbot-Lau interferometers (TLIs) to the relevant x-ray energy ranges. In this work, we present a preclinical Talbot-Lau prototype capable of imaging human-sized objects with proper image quality at clinically acceptable dose levels. The TLI is designed to match a setup of clinical relevance as closely as possible. The system provides a scan range of 120 × 30 cm 2 by using a scanning beam geometry. Its ultimate load is 100 kg. High aspect ratios and fine grid periods of the gratings ensure a reasonable setup length and clinically relevant image quality. The system is installed in a university hospital and is, therefore, exposed to the external influences of a clinical environment. To demonstrate the system's capabilities, a full-body scan of a euthanized pig was performed. In addition, freshly excised porcine lungs with an extrinsically provoked pneumothorax were mounted into a human thorax phantom and examined with the prototype. Both examination sequences resulted in clinically relevant image quality - even in the case of a skin entrance air kerma of only 0.3 mGy which is in the range of human thoracic imaging. The presented case of a pneumothorax and a reader study showed that the prototype's dark-field images provide added value for pulmonary diagnosis. We demonstrated that a dedicated design of a Talbot-Lau interferometer can be applied to medical imaging by constructing a preclinical Talbot-Lau prototype. We experienced that the system is feasible for imaging human-sized objects and the phase-stepping approach is suitable for clinical practice. Hence, we conclude that Talbot-Lau x-ray imaging has potential for clinical use and enhances the diagnostic power of medical x-ray imaging.

  19. Utility of Vascular Enhancement Technique (ClarifyTM) in Ultrasonographic Evaluation of Abdominal Vessels

    International Nuclear Information System (INIS)

    Oh, Jong Young; Cho, Jin Han; Choi, Jong Cheol; Shin, Tae Beom; Lee, Jin Hwa; Yoon, Seong Kuk; Nam, Kyung Jin

    2006-01-01

    Vascular enhancement (VE) technology(ClarifyTM) is a new technique in vascular, B-mode imaging. The purpose of this study was to evaluate the value of VE technology in ultrasonographic diagnosis of abdominal vasculature. Seventy-one adult patients (39 men and 32 women: age range, 25-89 years: mean age, 56 years) who had undergone abdominal ultrasonography were included in this study. The imaging was performed with a 1.8-4.0 MHz convex array transducer (SONOLINE, Antares, Siemens Medical Solutions, WA) by an abdominal radiologist. The radiologist obtained images of the same vascular area with each of conventional ultrasonography imaging (CUS), tissue harmonic imaging (THI), CUS plus VE technique and THI plus VE technique. Images were divided into normal (56) and abnormal (15) groups. The vessel visibility, conspicuity of the vascular wall and contrast resolution with adjacent structures were evaluated in the normal group, and the lesion conspicuity and border sharpness were evaluated in the abnormal group. On the PACS monitor, the images were graded into four grades by two radiologists in consensus. Statistical analysis was performed using Wilcoxon signed rank test. In the normal group, all parameters of the ultrasonographic imaging which applied the VE technique were superior to those of the imaging without VE technique (p < 0.05). In the abnormal group, combined use of VE technique with CUS or THI provided better results than CUS or THI alone in terms of lesion conspicuity and border sharpness (p < 0.05). THI combined with VE technique provided the best image quality among the 4 ultrasonographic methods examined in this study for the evaluation of both normal and abnormal abdominal vessels (p < 0.05). VE technology was a helpful technique to evaluate the abdominal vasculature. Furthermore, VE technique combined with THI provided better image quality than other ultrasonographic methods in the evaluation of abdominal vessels

  20. Longitudinal microvascularity in achilles tendinopathy (power doppler ultrasound, magnetic resonance imaging time-intensity curves and the Victorian Institute of Sport Assessment-Achilles questionnaire): a pilot study

    International Nuclear Information System (INIS)

    Richards, Paula J.; McCall, Iain W.; Day, Christopher; Belcher, John; Maffulli, Nicola

    2010-01-01

    To evaluate the imaging of the natural history of Achilles tendinopathy microvascularisation in comparison with symptoms, using a validated disease-specific questionnaire [the Victorian Institute of Sport Assessment-Achilles (VISA-A)]. A longitudinal prospective pilot study of nine patients with post-contrast magnetic resonance imaging (MRI), time-intensity curve (TIC) enhancement, ultrasound (US) and power Doppler (PD) evaluation of tendinopathy of the mid-Achilles tendon undergoing conservative management (eccentric exercise) over 1 year. There were five men and four women [mean age 47 (range 30-62) years]. Six asymptomatic tendons with normal US and MRI appearance showed less enhancement than the tibial metaphysis did and showed a flat, constant, but very low rate of enhancement in the bone and Achilles tendon (9-73 arbitrary TIC units). These normal Achilles tendons on imaging showed a constant size throughout the year (mean 4.9 mm). At baseline the TIC enhancement in those with tendinopathy ranged from 90 arbitrary units to 509 arbitrary units. Over time, 11 abnormal Achilles tendons, whose symptoms settled, were associated with a reduction in MRI enhancement mirrored by a reduction in the number of vessels on power Doppler (8.0 to 2.7), with an improvement in morphology and a reduction in tendon size (mean 15-10.6 mm). One tendon did not change its abnormal imaging features, despite improving symptoms. Two patients developed contralateral symptoms and tendinopathy, and one had more abnormal vascularity on power Doppler and higher MRI TIC peaks in the asymptomatic side. In patient with conservatively managed tendinopathy of the mid-Achilles tendon over 1 year there was a reduction of MRI enhancement and number of vessels on power Doppler, followed by morphological improvements and a reduction in size. Vessels per se related to the abnormal morphology and size of the tendon rather than symptoms. Symptoms improve before the Achilles size reduces and the

  1. An online detection system for aggregate sizes and shapes based on digital image processing

    Science.gov (United States)

    Yang, Jianhong; Chen, Sijia

    2017-02-01

    Traditional aggregate size measuring methods are time-consuming, taxing, and do not deliver online measurements. A new online detection system for determining aggregate size and shape based on a digital camera with a charge-coupled device, and subsequent digital image processing, have been developed to overcome these problems. The system captures images of aggregates while falling and flat lying. Using these data, the particle size and shape distribution can be obtained in real time. Here, we calibrate this method using standard globules. Our experiments show that the maximum particle size distribution error was only 3 wt%, while the maximum particle shape distribution error was only 2 wt% for data derived from falling aggregates, having good dispersion. In contrast, the data for flat-lying aggregates had a maximum particle size distribution error of 12 wt%, and a maximum particle shape distribution error of 10 wt%; their accuracy was clearly lower than for falling aggregates. However, they performed well for single-graded aggregates, and did not require a dispersion device. Our system is low-cost and easy to install. It can successfully achieve online detection of aggregate size and shape with good reliability, and it has great potential for aggregate quality assurance.

  2. Imaging in the diagnosis of juvenile nasopharyngeal angiofibroma

    Directory of Open Access Journals (Sweden)

    Satyaranjan Mishra

    2013-01-01

    Full Text Available Juvenile nasopharyngeal angiofibroma (JNA is a rare, benign, highly vascular, and locally aggressive tumor that predominantly occurs in adolescent males. Usually, the presenting symptom is a painless nasal obstruction or epistaxis; however, other symptoms may develop depending on the size and extent of the tumor mass. Owing to the vascularity of the tumor, incisional biopsy is not attempted. The diagnosis is dependent on multiplanar imaging modalities like Computed Tomography (CT, Magnetic Resonance Imaging (MRI, and Angiography. These imaging modalities help in assessing the tumor mass, pre-operative embolization of the feeder vessel, and treatment planning. Usually, patients with JNA are diagnosed by otorhinolaryngologists, but here, we present a rare case of JNA reporting to the dental hospital due to a tender palatal swelling.

  3. Calibration of Binocular Vision Sensors Based on Unknown-Sized Elliptical Stripe Images

    Directory of Open Access Journals (Sweden)

    Zhen Liu

    2017-12-01

    Full Text Available Most of the existing calibration methods for binocular stereo vision sensor (BSVS depend on a high-accuracy target with feature points that are difficult and costly to manufacture and. In complex light conditions, optical filters are used for BSVS, but they affect imaging quality. Hence, the use of a high-accuracy target with certain-sized feature points for calibration is not feasible under such complex conditions. To solve these problems, a calibration method based on unknown-sized elliptical stripe images is proposed. With known intrinsic parameters, the proposed method adopts the elliptical stripes located on the parallel planes as a medium to calibrate BSVS online. In comparison with the common calibration methods, the proposed method avoids utilizing high-accuracy target with certain-sized feature points. Therefore, the proposed method is not only easy to implement but is a realistic method for the calibration of BSVS with optical filter. Changing the size of elliptical curves projected on the target solves the difficulty of applying the proposed method in different fields of view and distances. Simulative and physical experiments are conducted to validate the efficiency of the proposed method. When the field of view is approximately 400 mm × 300 mm, the proposed method can reach a calibration accuracy of 0.03 mm, which is comparable with that of Zhang’s method.

  4. Semiautomated segmentation of blood vessels using ellipse-overlap criteria: Method and comparison to manual editing

    International Nuclear Information System (INIS)

    Shiffman, Smadar; Rubin, Geoffrey D.; Schraedley-Desmond, Pamela; Napel, Sandy

    2003-01-01

    Two-dimensional intensity-based methods for the segmentation of blood vessels from computed-tomography-angiography data often result in spurious segments that originate from other objects whose intensity distributions overlap with those of the vessels. When segmented images include spurious segments, additional methods are required to select segments that belong to the target vessels. We describe a method that allows experts to select vessel segments from sequences of segmented images with little effort. Our method uses ellipse-overlap criteria to differentiate between segments that belong to different objects and are separated in plane but are connected in the through-plane direction. To validate our method, we used it to extract vessel regions from volumes that were segmented via analysis of isolabel-contour maps, and showed that the difference between the results of our method and manually-edited results was within inter-expert variability. Although the total editing duration for our method, which included user-interaction and computer processing, exceeded that of manual editing, the extent of user interaction required for our method was about a fifth of that required for manual editing

  5. A quantitative study of ramped radio frequency, magnetization transfer, and slab thickness in three-dimensional time-of-flight magnetic resonance angiography in a patient population.

    Science.gov (United States)

    Goodrich, K C; Blatter, D D; Parker, D L; Du, Y P; Meyer, K J; Bernstein, M A

    1996-06-01

    The authors compare the effectiveness of various magnetic resonance (MR) angiography acquisition strategies in enhancing the visibility of small intracranial vessels. Blood vessel contrast-to-noise ratio (CNR) in time-of-flight MR angiography was studied as a function of vessel size and several selectable imaging parameters. Contrast-to-noise measurements were made on 257 vessel segments ranging in size from 0.3 mm to 4.2 mm in patients who recently had undergone intraarterial cerebral angiography. Imaging parameters studied included magnetization transfer, spatially variable radio frequency (RF) pulse profile (ramped RF), and imaging slab thickness. The combination of thin slabs (16 slices/slab), ramped RF, and magnetization transfer resulted in the highest CNR for all but the smallest vessel sizes. The smallest vessels (slab (64 slices/slab) with ramped RF and magnetization transfer. Magnetization transfer always improved vessel CNR, but the improvement diminished as the slab thickness was reduced. The CNR increased with a decrease in slab thickness for all but the smallest vessel sizes. Overall, the results provide a quantitative demonstration that inflow enhancement of blood is reduced for small vessels. Thus, whereas magnetization transfer is important at all vessel sizes, it becomes the primary factor in improving the visibility of the smallest vessels.

  6. An experimental system for the study of ultrasound exposure of isolated blood vessels

    International Nuclear Information System (INIS)

    Tokarczyk, Anna; Rivens, Ian; Symonds-Tayler, Richard; Ter Haar, Gail; Van Bavel, E

    2013-01-01

    An experimental system designed for the study of the effects of diagnostic or therapeutic ultrasound exposure on isolated blood vessels in the presence or absence of intraluminal contrast agent is described. The system comprised several components. A microscope was used to monitor vessel size (and thus vessel functionality), and potential leakage of intraluminal 70 kDa FITC-dextran fluorescence marker. A vessel chamber allowed the mounting of an isolated vessel whilst maintaining its viability, with pressure regulation for the control of intraluminal pressure and induction of flow for the infusion of contrast microbubbles. A fibre-optic hydrophone sensor mounted on the vessel chamber using a micromanipulator allowed pre-exposure targeting of the vessel to within 150 µm, and monitoring of acoustic cavitation emissions during exposures. Acoustic cavitation was also detected using changes in the ultrasound drive voltage and by detection of audible emissions using a submerged microphone. The suitability of this system for studying effects in the isolated vessel model has been demonstrated using a pilot study of 6 sham exposed and 18 high intensity focused ultrasound exposed vessels, with or without intraluminal contrast agent (SonoVue) within the vessels. (paper)

  7. A 2D driven 3D vessel segmentation algorithm for 3D digital subtraction angiography data

    International Nuclear Information System (INIS)

    Spiegel, M; Hornegger, J; Redel, T; Struffert, T; Doerfler, A

    2011-01-01

    Cerebrovascular disease is among the leading causes of death in western industrial nations. 3D rotational angiography delivers indispensable information on vessel morphology and pathology. Physicians make use of this to analyze vessel geometry in detail, i.e. vessel diameters, location and size of aneurysms, to come up with a clinical decision. 3D segmentation is a crucial step in this pipeline. Although a lot of different methods are available nowadays, all of them lack a method to validate the results for the individual patient. Therefore, we propose a novel 2D digital subtraction angiography (DSA)-driven 3D vessel segmentation and validation framework. 2D DSA projections are clinically considered as gold standard when it comes to measurements of vessel diameter or the neck size of aneurysms. An ellipsoid vessel model is applied to deliver the initial 3D segmentation. To assess the accuracy of the 3D vessel segmentation, its forward projections are iteratively overlaid with the corresponding 2D DSA projections. Local vessel discrepancies are modeled by a global 2D/3D optimization function to adjust the 3D vessel segmentation toward the 2D vessel contours. Our framework has been evaluated on phantom data as well as on ten patient datasets. Three 2D DSA projections from varying viewing angles have been used for each dataset. The novel 2D driven 3D vessel segmentation approach shows superior results against state-of-the-art segmentations like region growing, i.e. an improvement of 7.2% points in precision and 5.8% points for the Dice coefficient. This method opens up future clinical applications requiring the greatest vessel accuracy, e.g. computational fluid dynamic modeling.

  8. Effects of irradiation on renal vessels of rabbits

    International Nuclear Information System (INIS)

    Hanayama, Hirotaka

    1982-01-01

    The male rabbits weighing approximately 3 kg were divided into two groups: one group received irradiation to the left kidney through 6 x 4 cm field size with doses of 5 Gy, while the other group was irradiated with 50 Gy. The vessel casts were observed using the injection replica scanning electron microscopic method. In 50 Gy irradiated group, the surface of blood vessel's lumen became irregular with a decrease in the number of glomeruli at 5 days. Partial narrowing was also seen in the cortex and glomerular vessels. The number of glomeruli decreased by 48% one week later and 90% 4 weeks later. The cortex vessels progressively narrowed, and irregularity of the net-like structure was also observed. Similarly, a decrease in the number of glomeruli and partial narrowing of the blood vessels were seen at 5 days on the nonirradiated side, but the damage was considerably less than that on the irradiated side. In the 5 Gy irradiated group, a decrease in the number of glomeruli was seen 5 days later and it became 71% 5 days later and 81% one week later. It returned to 95% 4 weeks later. No changes whatsoever were seen in the non-irradiated side after 4 weeks and changes in the number of glomeruli were not observed. The vasculation of medulla showed no changes in the 50 Gy or the 5 Gy irradiated group. There were seen no significant changes in the blood vessel diameter. (J.P.N.)

  9. Contrast-enhanced ultrasonography depicts small tumor vessels for the evaluation of pancreatic tumors

    International Nuclear Information System (INIS)

    Okamoto, Yuko; Kawamoto, Hirofumi; Takaki, Akinobu; Ishida, Etsuji; Ogawa, Tsuneyoshi; Kuwaki, Kenji; Kobayashi, Yoshiyuki; Sakaguchi, Kohsaku; Shiratori, Yasushi

    2007-01-01

    Objective: The aim of this study is to evaluate the efficacy of contrast-enhanced ultrasonography for the diagnosis of pancreatic tumors. Materials and methods: Contrast-enhanced ultrasonography with Levovist was performed on 62 consecutive patients (53 with pancreatic cancer, 4 with islet cell tumor, 3 with inflammatory pancreatic tumor, and 2 with metastatic tumor). The vascular and perfusion image phases of the tumors were evaluated and compared with the findings of contrast-enhanced computed tomography. Results: Contrast-enhanced ultrasonography showed tumor vessels around and/or in the tumor at the vascular image phase in 79% of pancreatic cancer patients (42/53). At the perfusion image phase, 96% of pancreatic cancers (51/53) were classified as hypo-enhancement type. However, tiny spotty or irregular heterogeneous enhanced lesions were found in 84% of hypo-enhanced pancreatic cancer patients (43/51). The presence of small vessels at the vascular image phase was closely correlated with the presence of these intratumor regional enhanced lesions at the perfusion image phase (κ coefficient = 0.42). The sensitivity of contrast-enhanced ultrasonography (100%) for pancreatic cancer was superior to that of contrast-enhanced computed tomography (91%), but no significant difference was observed between the two (McNemar test: p = 0.063). Conclusion: Contrast-enhanced ultrasonography with Levovist successfully visualizes fine vessels and enhancement in pancreatic tumors, and is useful for evaluating pancreatic tumors

  10. Heavy wall pressure vessels for energy systems

    International Nuclear Information System (INIS)

    Canonico, D.A.

    Modifications of steels currently accepted in the Code appear to provide improved mechanical properties. These steels may permit the fabrication of larger diameter vessels with thinner section sizes and improved reliability and integrity. Adapting current specifications should expedite Code approval. Finally the challenge of improving welding procedures and adapting processes for field applications will result in higher quality weldments

  11. Normal anatomy of the lymphatic system in the CT-image

    International Nuclear Information System (INIS)

    Steinbrich, W.; Peters, P.E.

    1982-01-01

    To evaluate a pathologic process of a lymphatic node, detailed knowledge is required of the normal anatomy of the lumphatic system in an axial CT image. The anatomy is demonstrated in a comparative study before and after lymphography with CT-scans of patients with normal lymphadenographs. Hereby it appears that with the high-resolution scanning method and favourable imaging conditions even small lymphatic nodes can be differentiated without a lymphographic contrast technique. However, nerves and vessels cannot be differentiated. The extreme variability in the size of normal lymphatic nodes makes the differentiation of pathologic processes very difficult. (orig.) [de

  12. Ultrasound imaging with a micromotor; Micromotor ni yoru choonpa imaging

    Energy Technology Data Exchange (ETDEWEB)

    Oshiro, O.; Salimuzzaman, M.; Matani, A.; Chihara, K. [Nara Institute of Science and Technology, Nara (Japan); Asao, M. [Osaka National Hospital, Osaka (Japan)

    1998-03-01

    This paper describes a new ultrasound intravascular imaging system. In this system, an ultrasound probe consists of a micromotor, an ultrasound reflecting mirror attached with the micromotor and an ultrasound transducer. Ultrasound is scanned radially by a micromotor instead of a rotation transmitting wire and the rotation of the micromotor is performed and controlled by an external magnetic field. This ultrasound imaging system with a micromotor was applied to observe the inside of blood vessels through in vitro experiments. The preliminary results suggest that this system has the sufficient ability to define the blood vessel morphology and that the simple image processing enhances signal-to-noise ratio of the reconstructed image. 12 refs., 5 figs.

  13. Iter in vessel viewing system design and assessment activities

    Energy Technology Data Exchange (ETDEWEB)

    Neri, C., E-mail: carlo.neri@enea.it [Associazione EURATOM-ENEA sulla Fusione, Via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Costa, P.; Ferri De Collibus, M.; Florean, M.; Mugnaini, G.; Pillon, M.; Pollastrone, F.; Rossi, P. [Associazione EURATOM-ENEA sulla Fusione, Via Enrico Fermi 45, 00044 Frascati, Rome (Italy)

    2011-10-15

    The In Vessel Viewing System (IVVS) is fundamental remote handling equipment, which will be used to make a survey of the status of the blanket first wall and divertor plasma facing components. A prototype of a laser In Vessel Viewing and ranging System was developed and tested at ENEA laboratories in Frascati under EFDA task agreements, it is able to perform sub-millimetric bi-dimensional and three-dimensional images inside ITER during maintenance procedure allowing the evaluation of the state and damages of the in-vessel surface. The present prototype has been designed to operate under room conditions and starting from springtime 2009 a Grant with F4E is in progress for the design and the assessment of the IVVS system for ITER, keeping in account all the environmental conditions and constraints.

  14. Triple –E Vessels: Tonnage Measurement and Suez Canal Dues Assessment

    Directory of Open Access Journals (Sweden)

    Elsayed Hussein Galall

    2015-08-01

    Full Text Available Container is growing faster than GDP, Shipping lines always attempt to augment efficiencyby reducing cost and by attracting larger volumes of containers. As a result rising containerfreight rates the lines have been driven to increase economic of scale, by building mega shipsand fewer mere efficient port calls. In 2011 Maersk line ordered up to 20 new “Triple- E “Class of container vessels deliversbetween 2013- 2015. These class of mega container vessels have its way through Suez Canal,other companies CMA, CGM also ordered this type of mega container vessels, in order toreach higher profits due to the achieved economics of scale It is believed that 20000 TEUcould be the next target size. Present mega container fleet and any future feasible potential vessel capacity expansionmore than 18000 TEU put Suez Canal route in strong competitive position. MeanwhilePanama Canal will not be able to handle vessels larger than 12600 TEU even after itsexpansion in 2015.

  15. Strength-toughness requirements for thick walled high pressure vessels

    International Nuclear Information System (INIS)

    Kapp, J.A.

    1990-01-01

    The strength and toughness requirements of materials for use in high pressure vessels has been the subject of some discussion in the meetings of the Materials Task Group of the Special Working Group High Pressure Vessels. A fracture mechanics analysis has been performed to theoretically establish the required toughness for a high pressure vessel. This paper reports that the analysis performed is based on the validity requirement for plane strain fracture of fracture toughness test specimens. This is that at the fracture event, the crack length, uncracked ligament, and vessel length must each be greater than fifty times the crack tip plastic zone size for brittle fracture to occur. For high pressure piping applications, the limiting physical dimension is the uncracked ligament, as it can be assumed that the other dimensions are always greater than fifty times the crack tip plastic zone. To perform the fracture mechanics analysis several parameters must be known: these include vessel dimensions, material strength, degree of autofrettage, and design pressure. Results of the analysis show, remarkably, that the effects of radius ratio, pressure and degree of autofrettage can be ignored when establishing strength and toughness requirements for code purposes. The only parameters that enter into the calculation are yield strength, toughness and vessel thickness. The final results can easily be represented as a graph of yield strength against toughness on which several curves, one for each vessel thickness, are plotted

  16. Estimation of the flow resistances exerted in coronary arteries using a vessel length-based method.

    Science.gov (United States)

    Lee, Kyung Eun; Kwon, Soon-Sung; Ji, Yoon Cheol; Shin, Eun-Seok; Choi, Jin-Ho; Kim, Sung Joon; Shim, Eun Bo

    2016-08-01

    Flow resistances exerted in the coronary arteries are the key parameters for the image-based computer simulation of coronary hemodynamics. The resistances depend on the anatomical characteristics of the coronary system. A simple and reliable estimation of the resistances is a compulsory procedure to compute the fractional flow reserve (FFR) of stenosed coronary arteries, an important clinical index of coronary artery disease. The cardiac muscle volume reconstructed from computed tomography (CT) images has been used to assess the resistance of the feeding coronary artery (muscle volume-based method). In this study, we estimate the flow resistances exerted in coronary arteries by using a novel method. Based on a physiological observation that longer coronary arteries have more daughter branches feeding a larger mass of cardiac muscle, the method measures the vessel lengths from coronary angiogram or CT images (vessel length-based method) and predicts the coronary flow resistances. The underlying equations are derived from the physiological relation among flow rate, resistance, and vessel length. To validate the present estimation method, we calculate the coronary flow division over coronary major arteries for 50 patients using the vessel length-based method as well as the muscle volume-based one. These results are compared with the direct measurements in a clinical study. Further proving the usefulness of the present method, we compute the coronary FFR from the images of optical coherence tomography.

  17. Cholinergic innervation of human mesenteric lymphatic vessels.

    Science.gov (United States)

    D'Andrea, V; Bianchi, E; Taurone, S; Mignini, F; Cavallotti, C; Artico, M

    2013-11-01

    The cholinergic neurotransmission within the human mesenteric lymphatic vessels has been poorly studied. Therefore, our aim is to analyse the cholinergic nerve fibres of lymphatic vessels using the traditional enzymatic techniques of staining, plus the biochemical modifications of acetylcholinesterase (AChE) activity. Specimens obtained from human mesenteric lymphatic vessels were subjected to the following experimental procedures: 1) drawing, cutting and staining of tissues; 2) staining of total nerve fibres; 3) enzymatic staining of cholinergic nerve fibres; 4) homogenisation of tissues; 5) biochemical amount of proteins; 6) biochemical amount of AChE activity; 6) quantitative analysis of images; 7) statistical analysis of data. The mesenteric lymphatic vessels show many AChE positive nerve fibres around their wall with an almost plexiform distribution. The incubation time was performed at 1 h (partial activity) and 6 h (total activity). Moreover, biochemical dosage of the same enzymatic activity confirms the results obtained with morphological methods. The homogenates of the studied tissues contain strong AChE activity. In our study, the lymphatic vessels appeared to contain few cholinergic nerve fibres. Therefore, it is expected that perivascular nerve stimulation stimulates cholinergic nerves innervating the mesenteric arteries to release the neurotransmitter AChE, which activates muscarinic or nicotinic receptors to modulate adrenergic neurotransmission. These results strongly suggest, that perivascular cholinergic nerves have little or no effect on the adrenergic nerve function in mesenteric arteries. The cholinergic nerves innervating mesenteric arteries do not mediate direct vascular responses.

  18. Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography.

    Science.gov (United States)

    Sampson, Danuta M; Gong, Peijun; An, Di; Menghini, Moreno; Hansen, Alex; Mackey, David A; Sampson, David D; Chen, Fred K

    2017-06-01

    To evaluate the impact of image magnification correction on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurements using optical coherence tomography angiography (OCTA). Participants with healthy retinas were recruited for ocular biometry, refraction, and RTVue XR Avanti OCTA imaging with the 3 × 3-mm protocol. The foveal and parafoveal SRVD and FAZA were quantified with custom software before and after correction for magnification error using the Littman and the modified Bennett formulae. Relative changes between corrected and uncorrected SRVD and FAZA were calculated. Forty subjects were enrolled and the median (range) age of the participants was 30 (18-74) years. The mean (range) spherical equivalent refractive error was -1.65 (-8.00 to +4.88) diopters and mean (range) axial length was 24.42 mm (21.27-28.85). Images from 13 eyes were excluded due to poor image quality leaving 67 for analysis. Relative changes in foveal and parafoveal SRVD and FAZA after correction ranged from -20% to +10%, -3% to +2%, and -20% to +51%, respectively. Image size correction in measurements of foveal SRVD and FAZA was greater than 5% in 51% and 74% of eyes, respectively. In contrast, 100% of eyes had less than 5% correction in measurements of parafoveal SRVD. Ocular biometry should be performed with OCTA to correct image magnification error induced by axial length variation. We advise caution when interpreting interocular and interindividual comparisons of SRVD and FAZA derived from OCTA without image size correction.

  19. Elimination of the risk of brittle fracture in thick welded pressure vessels

    International Nuclear Information System (INIS)

    Leymonie, C.; Genevray, R.

    1975-01-01

    The builder of welded pressure vessels faces the risk of brittle fracture throughout fabrication. He is forced to observe many precautions, in selecting the following: materials possessing good impact strength in the service conditions of the vessels; filler materials preventing transverse cracking of the welds: welding parameters preventing cold cracking. Fracture mechanics establish the relationships between material characteristics and critical defect size for a given set of service conditions. These principles must be expanded to increase the safety of thick pressure vessels. However, in order to derive maximum benefit, a major effort must be applied to increasing the effectiveness of nondestructive testing [fr

  20. Segmentation of retinal blood vessels for detection of diabetic retinopathy: A review

    Directory of Open Access Journals (Sweden)

    Rezty Amalia Aras

    2016-05-01

    Full Text Available Diabetic detinopathy (DR is effect of diabetes mellitus to the human vision that is the major cause of blindness. Early diagnosis of DR is an important requirement in diabetes treatment. Retinal fundus image is commonly used to observe the diabetic retinopathy symptoms. It can present retinal features such as blood vessel and also capture the pathologies which may lead to DR. Blood vessel is one of retinal features which can show the retina pathologies. It can be extracted from retinal image by image processing with following stages: pre-processing, segmentation, and post-processing. This paper contains a review of public retinal image dataset and several methods from various conducted researches. All discussed methods are applicable to each researcher cases. There is no further analysis to conclude the best method which can be used for general cases. However, we suggest morphological and multiscale method that gives the best accuracy in segmentation.

  1. Evaluation for In-Vessel Retention Capabilities with In-Vessel Injection and External Reactor Vessel Cooling

    International Nuclear Information System (INIS)

    Lee, Jeong Seong; Ryu, In Chul; Moon, Young Tae

    2016-01-01

    If the accident has not progressed to the point of substantial changes in the core geometry, establishing adequate cooling is as straightforward as re-establishing flow through the reactor core. However, if the accident has progressed to the point where the core geometry is substantially altered as a result of material melting and relocation, as was the case in the TMI-2 accident, the means of cooling the debris are not as straightforward. From this time on, the reactor core was either completely or nearly covered by water, with high pressure injection flow initiated shortly after three hours into the accident. However, the core debris was not coolable in this configuration and a substantial quantity of molten core material drained into the bypass region, with approximately twenty metric tons of molten debris draining into the reactor pressure vessel (RPV) lower head. Hence, the core configuration developed at approximately three hours into the accident was not coolable, even submerged in water. The purpose of this paper is to evaluate in-vessel retention capabilities with in-vessel injection (IVI) and external reactor vessel cooling (ERVC) available in a reactor application by using the integrated severe accident analysis code. The MAAP5 models were improved to facilitate evaluation of the in-vessel retention capability of APR1400. In-vessel retention capabilities have been analyzed for the APR1400 using the MAAP5.03 code. The results show that in-vessel retention is feasible when in-vessel injection is initiated within a relatively short time frame under the simulation condition used in the present study

  2. Evaluation for In-Vessel Retention Capabilities with In-Vessel Injection and External Reactor Vessel Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Seong; Ryu, In Chul; Moon, Young Tae [KEPCO Engineering and Construction Co. Ltd., Deajeon (Korea, Republic of)

    2016-10-15

    If the accident has not progressed to the point of substantial changes in the core geometry, establishing adequate cooling is as straightforward as re-establishing flow through the reactor core. However, if the accident has progressed to the point where the core geometry is substantially altered as a result of material melting and relocation, as was the case in the TMI-2 accident, the means of cooling the debris are not as straightforward. From this time on, the reactor core was either completely or nearly covered by water, with high pressure injection flow initiated shortly after three hours into the accident. However, the core debris was not coolable in this configuration and a substantial quantity of molten core material drained into the bypass region, with approximately twenty metric tons of molten debris draining into the reactor pressure vessel (RPV) lower head. Hence, the core configuration developed at approximately three hours into the accident was not coolable, even submerged in water. The purpose of this paper is to evaluate in-vessel retention capabilities with in-vessel injection (IVI) and external reactor vessel cooling (ERVC) available in a reactor application by using the integrated severe accident analysis code. The MAAP5 models were improved to facilitate evaluation of the in-vessel retention capability of APR1400. In-vessel retention capabilities have been analyzed for the APR1400 using the MAAP5.03 code. The results show that in-vessel retention is feasible when in-vessel injection is initiated within a relatively short time frame under the simulation condition used in the present study.

  3. Concrete containment vessels (CCV) for nuclear power plants, (1)

    International Nuclear Information System (INIS)

    Ibe, Yukimi; Kitajima, Masatake

    1977-01-01

    Containment vessels (CV) and the construction of concrete containment vessels (CCV) for nuclear power plants are described generally, and their use and techniques in foreign countries are illustrated, in connection with the introduction of CCV to Japanese nuclear power plants. The introduction deals with the construction plan of Japanese nuclear power plants, and with the difficulties in the steel CV for large scale construction. The investigations, tests and researches are not yet sufficient. The prompt establishment of safety supported by technical criteria, analytical methods and experiments is desired. The second part deals with the consideration for aseismatic design, construction, function and characteristics of CCV. The classification and currently employed CCV, which is mainly reinforced concrete containment vessels (RCCV), are described, and the typical CCV employed for BWR is illustrated. Further, the typical arrangement of reinforcing steels at the cylindrical portion and the dome portion of RCCV is illustrated. The third part deals with the present state of CCV abroad. A prestressed concrete containment vessel (PCCV) of Turkey Point power plant is illustrated as a typical example of CCV. The tests reported in the international meeting for the design, construction and operation of concrete pressure vessels and concrete containment vessels at York University in England in 1975 are reviewed. Typical examples of the design conditions, the size and form, and the construction procedure for PCCV and RCCV abroad are reviewed. (Iwakiri, K.)

  4. Differentiating gold nanorod samples using particle size and shape distributions from transmission electron microscope images

    Science.gov (United States)

    Grulke, Eric A.; Wu, Xiaochun; Ji, Yinglu; Buhr, Egbert; Yamamoto, Kazuhiro; Song, Nam Woong; Stefaniak, Aleksandr B.; Schwegler-Berry, Diane; Burchett, Woodrow W.; Lambert, Joshua; Stromberg, Arnold J.

    2018-04-01

    Size and shape distributions of gold nanorod samples are critical to their physico-chemical properties, especially their longitudinal surface plasmon resonance. This interlaboratory comparison study developed methods for measuring and evaluating size and shape distributions for gold nanorod samples using transmission electron microscopy (TEM) images. The objective was to determine whether two different samples, which had different performance attributes in their application, were different with respect to their size and/or shape descriptor distributions. Touching particles in the captured images were identified using a ruggedness shape descriptor. Nanorods could be distinguished from nanocubes using an elongational shape descriptor. A non-parametric statistical test showed that cumulative distributions of an elongational shape descriptor, that is, the aspect ratio, were statistically different between the two samples for all laboratories. While the scale parameters of size and shape distributions were similar for both samples, the width parameters of size and shape distributions were statistically different. This protocol fulfills an important need for a standardized approach to measure gold nanorod size and shape distributions for applications in which quantitative measurements and comparisons are important. Furthermore, the validated protocol workflow can be automated, thus providing consistent and rapid measurements of nanorod size and shape distributions for researchers, regulatory agencies, and industry.

  5. Effect of blood vessels on light distribution in optogenetic stimulation of cortex.

    Science.gov (United States)

    Azimipour, Mehdi; Atry, Farid; Pashaie, Ramin

    2015-05-15

    In this Letter, the impact of blood vessels on light distribution during photostimulation of cortical tissue in small rodents is investigated. Brain optical properties were extracted using a double-integrating sphere setup, and optical coherence tomography was used to image cortical vessels and capillaries to generate a three-dimensional angiogram of the cortex. By combining these two datasets, a complete volumetric structure of the cortical tissue was developed and linked to a Monte Carlo code which simulates light propagation in this inhomogeneous structure and illustrates the effect of blood vessels on the penetration depth and pattern preservation in optogenetic stimulation.

  6. A three-temperature model of selective photothermolysis for laser treatment of port wine stain containing large malformed blood vessels

    International Nuclear Information System (INIS)

    Li, D.; Wang, G.X.; He, Y.L.; Wu, W.J.; Chen, B.

    2014-01-01

    As congenital vascular malformations, port wine stain (PWS) is composed of ectatic venular capillary blood vessels buried within healthy dermis. In clinic, pulsed dye laser (PDL) in visible band (e.g. 585 nm) together with cryogen spray cooling (CSC) have become the golden standard for treatment of PWS. However, due to the limited energy deposition of the PDL in blood, large blood vessels are likely to survive from the laser irradiation. As a result, complete clearance of the lesions is rarely achieved. Assuming the local thermal non-equilibrium in skin tissue during the laser surgery, a three-temperature model is proposed to treat the PWS tissue as a porous media composed of a non-absorbing dermal matrix buried with the blood as well as the large malformed blood vessels. Three energy equations are constructed and solved coupling for the temperature of the blood in average-sized PWS vessels, non-absorbing dermal tissues and large malformed blood vessels, respectively. Subsequently, the thermal responses of human skin to visible (585 nm) and near-infrared (1064 nm) laser irradiations with various pulse durations in conjunction with cryogen spray cooling are investigated by the new model, and Arrhenius integral is used to analyze the thermal damage. The simulations show that the short pulse duration of 1.5 ms results in a higher selective heating of blood over epidermis, which will lead to a desired clinic outcome than the longer pulse duration. Due to a much deeper light penetration depth, laser irradiation with 1064 nm in wavelength is superior to that with 585 nm in treating patients with cutaneous hyper-vascular malformation. Complete coagulations are predicted in large-sized and deeply extending blood vessels by 1064 nm laser. - Highlights: •A three-temperature model is proposed for the laser treatment of port wine stain (PWS). •Average sized and large malformed blood vessels in porous medium (tissue) are considered. •Thermal responses of PWS to

  7. Digital vascular imaging

    International Nuclear Information System (INIS)

    Ludwig, J.W.; Engels, B.C.H.

    1981-01-01

    Digitalizing videosignals from an image intensifying TV-chain, followed by subtraction, contrast intensifying, and reformation to analogous signal deliver angiography pictures of high quality after intravenous injection of the contrast medium. As the examination is only little invasive it can be carried out on outdoor patients or in the polyclinics. The possibilities of the digital vessel imagination (DVI) are shown at vessel images of different parts of the body; a 36 cm image intensifyer which can be switched to 3 different sorts of operation and has a plumbicon-TV recording tube is used as receiver. (orig.) [de

  8. MR imaging of carotid webs

    International Nuclear Information System (INIS)

    Boesen, Mari E.; Eswaradass, Prasanna Venkatesan; Singh, Dilip; Mitha, Alim P.; Menon, Bijoy K.; Goyal, Mayank; Frayne, Richard

    2017-01-01

    We propose a magnetic resonance (MR) imaging protocol for the characterization of carotid web morphology, composition, and vessel wall dynamics. The purpose of this case series was to determine the feasibility of imaging carotid webs with MR imaging. Five patients diagnosed with carotid web on CT angiography were recruited to undergo a 30-min MR imaging session. MR angiography (MRA) images of the carotid artery bifurcation were acquired. Multi-contrast fast spin echo (FSE) images were acquired axially about the level of the carotid web. Two types of cardiac phase resolved sequences (cineFSE and cine phase contrast) were acquired to visualize the elasticity of the vessel wall affected by the web. Carotid webs were identified on MRA in 5/5 (100%) patients. Multi-contrast FSE revealed vessel wall thickening and cineFSE demonstrated regional changes in distensibility surrounding the webs in these patients. Our MR imaging protocol enables an in-depth evaluation of patients with carotid webs: morphology (by MRA), composition (by multi-contrast FSE), and wall dynamics (by cineFSE). (orig.)

  9. MR imaging of carotid webs

    Energy Technology Data Exchange (ETDEWEB)

    Boesen, Mari E. [University of Calgary, Department of Biomedical Engineering, Calgary (Canada); Foothills Medical Centre, Seaman Family MR Research Centre, Calgary (Canada); Eswaradass, Prasanna Venkatesan; Singh, Dilip; Mitha, Alim P.; Menon, Bijoy K. [University of Calgary, Department of Clinical Neurosciences, Calgary (Canada); Foothills Medical Centre, Calgary Stroke Program, Calgary (Canada); Goyal, Mayank [Foothills Medical Centre, Calgary Stroke Program, Calgary (Canada); University of Calgary, Department of Radiology, Calgary (Canada); Frayne, Richard [Foothills Medical Centre, Seaman Family MR Research Centre, Calgary (Canada); University of Calgary, Hotchkiss Brain Institute, Calgary (Canada)

    2017-04-15

    We propose a magnetic resonance (MR) imaging protocol for the characterization of carotid web morphology, composition, and vessel wall dynamics. The purpose of this case series was to determine the feasibility of imaging carotid webs with MR imaging. Five patients diagnosed with carotid web on CT angiography were recruited to undergo a 30-min MR imaging session. MR angiography (MRA) images of the carotid artery bifurcation were acquired. Multi-contrast fast spin echo (FSE) images were acquired axially about the level of the carotid web. Two types of cardiac phase resolved sequences (cineFSE and cine phase contrast) were acquired to visualize the elasticity of the vessel wall affected by the web. Carotid webs were identified on MRA in 5/5 (100%) patients. Multi-contrast FSE revealed vessel wall thickening and cineFSE demonstrated regional changes in distensibility surrounding the webs in these patients. Our MR imaging protocol enables an in-depth evaluation of patients with carotid webs: morphology (by MRA), composition (by multi-contrast FSE), and wall dynamics (by cineFSE). (orig.)

  10. Fine focal spot size improves image quality in computed tomography abdomen and pelvis

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Yin P.; Low, Keat; Kuganesan, Ahilan [Monash Health, Diagnostic Imaging Department, 246, Clayton Road, Clayton, Victoria (Australia); Lau, Kenneth K. [Monash Health, Diagnostic Imaging Department, 246, Clayton Road, Clayton, Victoria (Australia); Monash University, Department of Medicine, Faculty of Medicine, Nursing and Health Sciences, Victoria (Australia); Buchan, Kevin [Philips Healthcare, Clinical Science, PO Box 312, Mont Albert, Victoria (Australia); Oh, Lawrence Chia Wei [Flinders Medical Centre, Division of Medical Imaging, Bedford Park South (Australia); Huynh, Minh [Swinburne University, Department of Statistics, Data Science and Epidemiology, School of Health Sciences, Faculty of Health, Arts and Design, Hawthorn (Australia)

    2016-12-15

    To compare the image quality between fine focal spot size (FFSS) and standard focal spot size (SFSS) in computed tomography of the abdomen and pelvis (CTAP) This retrospective review included all consecutive adult patients undergoing contrast-enhanced CTAP between June and September 2014. Two blinded radiologists assessed the margin clarity of the abdominal viscera and the detected lesions using a five-point grading scale. Cohen's kappa test was used to examine the inter-observer reliability between the two reviewers for organ margin clarity. Mann-Whitney U testing was utilised to assess the statistical difference of the organ and lesion margin clarity. 100 consecutive CTAPs were recruited. 52 CTAPs were examined with SFSS of 1.1 x 1.2 mm and 48 CTAPs were examined with FFSS of 0.6 x 0.7 mm. Results showed that there was substantial agreement for organ margin clarity (mean κ = 0.759, p < 0.001) among the reviewers. FFSS produces images with clearer organ margins (U = 76194.0, p < 0.001, r = 0.523) and clearer lesion margins (U = 239, p = 0.052, r = 0.269). FFSS CTAP improves image quality in terms of better organ and lesion margin clarity. Fine focus CT scanning is a novel technique that may be applied in routine CTAP imaging. (orig.)

  11. Automated detection and classification of major retinal vessels for determination of diameter ratio of arteries and veins

    Science.gov (United States)

    Muramatsu, Chisako; Hatanaka, Yuji; Iwase, Tatsuhiko; Hara, Takeshi; Fujita, Hiroshi

    2010-03-01

    Abnormalities of retinal vasculatures can indicate health conditions in the body, such as the high blood pressure and diabetes. Providing automatically determined width ratio of arteries and veins (A/V ratio) on retinal fundus images may help physicians in the diagnosis of hypertensive retinopathy, which may cause blindness. The purpose of this study was to detect major retinal vessels and classify them into arteries and veins for the determination of A/V ratio. Images used in this study were obtained from DRIVE database, which consists of 20 cases each for training and testing vessel detection algorithms. Starting with the reference standard of vasculature segmentation provided in the database, major arteries and veins each in the upper and lower temporal regions were manually selected for establishing the gold standard. We applied the black top-hat transformation and double-ring filter to detect retinal blood vessels. From the extracted vessels, large vessels extending from the optic disc to temporal regions were selected as target vessels for calculation of A/V ratio. Image features were extracted from the vessel segments from quarter-disc to one disc diameter from the edge of optic discs. The target segments in the training cases were classified into arteries and veins by using the linear discriminant analysis, and the selected parameters were applied to those in the test cases. Out of 40 pairs, 30 pairs (75%) of arteries and veins in the 20 test cases were correctly classified. The result can be used for the automated calculation of A/V ratio.

  12. Rapid analysis of vessel elements (RAVE: a tool for studying physiologic, pathologic and tumor angiogenesis.

    Directory of Open Access Journals (Sweden)

    Marc E Seaman

    Full Text Available Quantification of microvascular network structure is important in a myriad of emerging research fields including microvessel remodeling in response to ischemia and drug therapy, tumor angiogenesis, and retinopathy. To mitigate analyst-specific variation in measurements and to ensure that measurements represent actual changes in vessel network structure and morphology, a reliable and automatic tool for quantifying microvascular network architecture is needed. Moreover, an analysis tool capable of acquiring and processing large data sets will facilitate advanced computational analysis and simulation of microvascular growth and remodeling processes and enable more high throughput discovery. To this end, we have produced an automatic and rapid vessel detection and quantification system using a MATLAB graphical user interface (GUI that vastly reduces time spent on analysis and greatly increases repeatability. Analysis yields numerical measures of vessel volume fraction, vessel length density, fractal dimension (a measure of tortuosity, and radii of murine vascular networks. Because our GUI is open sourced to all, it can be easily modified to measure parameters such as percent coverage of non-endothelial cells, number of loops in a vascular bed, amount of perfusion and two-dimensional branch angle. Importantly, the GUI is compatible with standard fluorescent staining and imaging protocols, but also has utility analyzing brightfield vascular images, obtained, for example, in dorsal skinfold chambers. A manually measured image can be typically completed in 20 minutes to 1 hour. In stark comparison, using our GUI, image analysis time is reduced to around 1 minute. This drastic reduction in analysis time coupled with increased repeatability makes this tool valuable for all vessel research especially those requiring rapid and reproducible results, such as anti-angiogenic drug screening.

  13. Method and apparatus for physical separation of different sized nanostructures

    Science.gov (United States)

    Roberts, Christopher B.; Saunders, Steven R.

    2012-07-10

    The present application provides apparatuses and methods for the size-selective fractionation of ligand-capped nanoparticles that utilizes the tunable thermophysical properties of gas-expanded liquids. The nanoparticle size separation processes are based on the controlled reduction of the solvent strength of an organic phase nanoparticle dispersion through increases in concentration of the antisolvent gas, such as CO.sub.2, via pressurization. The method of nanomaterial separation contains preparing a vessel having a solvent and dispersed nanoparticles, pressurizing the chamber with a gaseous antisolvent, and causing a first amount of the nanoparticles to precipitate, transporting the solution to a second vessel, pressurizing the second vessel with the gaseous antisolvent and causing further nanoparticles to separate from the solution.

  14. Proactive life extension of pressure vessels

    Science.gov (United States)

    Mager, Lloyd

    1998-03-01

    place while our vessels are in service. As the inspection takes place we are able to view a real time image of detected discontinuities on a video monitor. The B-scan ultrasonic technique is allowing us to perform fast accurate examinations covering up to 95% of the surface area of each pressure vessel. Receiving data on 95% of a pressure vessel provides us with a lot of useful information. We use this data to determine the condition of each pressure vessel. Once the condition is known the vessels are classed by risk. The risk level is then managed by making decisions related to repair, operating parameters, accepting and monitoring or replacement of the equipment. Inspection schedules are set at maximum intervals and reinspection is minimized for the vessels that are not at risk. The remaining life of each pressure vessel is determined, mechanical integrity is proven and regulatory requirements are met. Abbott Laboratories is taking this proactive approach because we understand that our process equipment is a critical element for successful operation. A run to failure practice would never allow Abbott Laboratories to achieve the corporation's objective of being the world's leading health care company. Nondestructive state of the art technology and the understanding of its capabilities and limitations are key components of a proactive program for life extension of pressure vessels. 26

  15. Pressurized subsampling system for pressured gas-hydrate-bearing sediment: Microscale imaging using X-ray computed tomography

    International Nuclear Information System (INIS)

    Jin, Yusuke; Konno, Yoshihiro; Nagao, Jiro

    2014-01-01

    A pressurized subsampling system was developed for pressured gas hydrate (GH)-bearing sediments, which have been stored under pressure. The system subsamples small amounts of GH sediments from cores (approximately 50 mm in diameter and 300 mm in height) without pressure release to atmospheric conditions. The maximum size of the subsamples is 12.5 mm in diameter and 20 mm in height. Moreover, our system transfers the subsample into a pressure vessel, and seals the pressure vessel by screwing in a plug under hydraulic pressure conditions. In this study, we demonstrated pressurized subsampling from artificial xenon-hydrate sediments and nondestructive microscale imaging of the subsample, using a microfocus X-ray computed tomography (CT) system. In addition, we estimated porosity and hydrate saturation from two-dimensional X-ray CT images of the subsamples

  16. Design, fabrication and test of double-wall vacuum vessel for JT-60U

    International Nuclear Information System (INIS)

    Uchikawa, Takashi; Ioki, Kimihiro; Ninomiya, Hiromasa.

    1994-01-01

    A double-wall vacuum vessel was designed and fabricated for JT-60U (an upgraded machine of JT-60), which has a plasma current up to 6 MA and a large plasma volume (100 m 3 ). A new concept of Inconel 625 all-welded structure was adopted to the vessel, that comprises an inner plate, square tubes and an outer plate. The vacuum vessel with a multi-arc D-shaped cross section was fabricated by using hot-sizing press. The electromagnetic and structural analysis has been performed for plasma disruption loads. Dynamic responses of the vessel were measured during plasma disruptions, and the observed displacement had a good agreement with the result of FEM analysis. (author)

  17. Bursting tests on pressure vessels with cracks differing in configuration and location

    International Nuclear Information System (INIS)

    Stahlberg, R.

    1978-01-01

    For assessing the safety of nuclear pressure vessels exhibiting cracks, bursting test were carried out on a series of medium-size pressure vessels with and without welded nozzles and exhibiting cracks differing in configuration and location. The linear-elastic approach proved to be sufficiently accurate for straight strain conditions up to the onset of general yielding. Other analytical methods were successfully used to cover the plastic region. (orig.) [de

  18. Size-dependent endocytosis of gold nanoparticles studied by three-dimensional mapping of plasmonic scattering images

    Directory of Open Access Journals (Sweden)

    Lee Chia-Wei

    2010-12-01

    Full Text Available Abstract Background Understanding the endocytosis process of gold nanoparticles (AuNPs is important for the drug delivery and photodynamic therapy applications. The endocytosis in living cells is usually studied by fluorescent microscopy. The fluorescent labeling suffers from photobleaching. Besides, quantitative estimation of the cellular uptake is not easy. In this paper, the size-dependent endocytosis of AuNPs was investigated by using plasmonic scattering images without any labeling. Results The scattering images of AuNPs and the vesicles were mapped by using an optical sectioning microscopy with dark-field illumination. AuNPs have large optical scatterings at 550-600 nm wavelengths due to localized surface plasmon resonances. Using an enhanced contrast between yellow and blue CCD images, AuNPs can be well distinguished from cellular organelles. The tracking of AuNPs coated with aptamers for surface mucin glycoprotein shows that AuNPs attached to extracellular matrix and moved towards center of the cell. Most 75-nm-AuNPs moved to the top of cells, while many 45-nm-AuNPs entered cells through endocytosis and accumulated in endocytic vesicles. The amounts of cellular uptake decreased with the increase of particle size. Conclusions We quantitatively studied the endocytosis of AuNPs with different sizes in various cancer cells. The plasmonic scattering images confirm the size-dependent endocytosis of AuNPs. The 45-nm-AuNP is better for drug delivery due to its higher uptake rate. On the other hand, large AuNPs are immobilized on the cell membrane. They can be used to reconstruct the cell morphology.

  19. Impact of radiation embrittlement on integrity of pressure vessel supports for two PWR plants

    Energy Technology Data Exchange (ETDEWEB)

    Cheverton, R.D.; Pennell, W.E.; Robinson, G.C.; Nanstad, R.K.

    1989-01-01

    Recent data from the HFIR vessel surveillance program indicate a substantial radiation embrittlement rate effect at low irradiation temperatures (/approximately/120/degree/F) for A212-B, A350-LF3, A105-II, and corresponding welds. PWR vessel supports are fabricated of similar materials and are subjected to the same low temperatures and fast neutron fluxes (10/sup 8/ to 10/sup 9/ neutrons/cm/sup 2//center dot/s, E > 1.0 MeV) as those in the HFIR vessel. Thus, the embrittlement rate of these structures may be greater than previously anticipated. A study sponsored by the NRC is under way at ORNL to determine the impact of the rate effect on PWR vessel-support life expectancy. The scope includes the interpretation and application of the HFIR data, a survey of all light-water-reactor vessel support designs, and a structural and fracture-mechanics analysis of the supports for two specific PWR plants of particular interest with regard to a potential for support failure as a result of propagation of flaws. Calculations performed thus far indicate best-estimate critical flaw sizes, corresponding to 32 EFPY, of /approximately/0.2 in. for one plant and /approximately/0.4 in. for the other. These flaw sizes are small enough to be of concern. However, it appears that low-cycle fatigue is not a viable mechanism for creation of flaws of this size, and thus, presumably, such flaws would have to exist at the time of fabrication. 59 refs., 128 figs., 49 tabs.

  20. Multiple shell pressure vessel

    International Nuclear Information System (INIS)

    Wedellsborg, B.W.

    1988-01-01

    A method is described of fabricating a pressure vessel comprising the steps of: attaching a first inner pressure vessel having means defining inlet and outlet openings to a top flange, placing a second inner pressure vessel, having means defining inlet and outlet opening, concentric with and spaced about the first inner pressure vessel and attaching the second inner pressure vessel to the top flange, placing an outer pressure vessel, having inlet and outlet openings, concentric with and spaced apart about the second inner pressure vessel and attaching the outer pressure vessel to the top flange, attaching a generally cylindrical inner inlet conduit and a generally cylindrical inner outlet conduit respectively to the inlet and outlet openings in the first inner pressure vessel, attaching a generally cylindrical outer inlet conduit and a generally cylindrical outer outlet conduit respectively to the inlet and outlet opening in the second inner pressure vessel, heating the assembled pressure vessel to a temperature above the melting point of a material selected from the group, lead, tin, antimony, bismuth, potassium, sodium, boron and mixtures thereof, filling the space between the first inner pressure vessel and the second inner pressure vessel with material selected from the group, filling the space between the second inner pressure vessel and the outer pressure vessel with material selected from the group, and pressurizing the material filling the spaces between the pressure vessels to a predetermined pressure, the step comprising: pressurizing the spaces to a pressure whereby the wall of the first inner pressure vessel is maintained in compression during steady state operation of the pressure vessel

  1. Longitudinal in vivo MR imaging of live earthworms.

    Science.gov (United States)

    Budán, Ferenc; Kovács, Noémi; Engelmann, Péter; Horváth, Ildikó; Veres, Dániel S; Németh, Péter; Szigeti, Krisztián; Máthé, Domokos

    2014-11-01

    Earthworm (Oligochaeta, Lumbricidae) species are used widely in eco-toxicological tests especially with contaminated soils. These long-term tests are reliable, but a high sample size is needed. Magnetic resonance imaging (MRI) can produce fast, robust, sensitive, and longitudinal morphological results using a small sample size. Performing longitudinal in vivo examinations of earthworms using MRI requires the need for anesthetics to completely avoid earthworm's moving. Our goal was to develop a simple and non-invasive method to anesthetize earthworms for in vivo longitudinal imaging studies. We investigated a number of different anesthesia methods and found that propan-2-ol and its vapor was optimal. We used a commercial sequential nanoScan® PET/MRI system (Mediso Ltd, Hungary, Budapest) to explore feasibility of MR imaging in immobilized earthworms. It was possible to visualize via micro MRI the brain, gastrointestinal tract, seminal vesicles, calciferous gland (Morren gland), and main blood vessels of the circulatory system. Our findings show the possibilities to examine changes in morphology using MRI of certain organs using a reversible, long-term immobilization method. © 2014 Wiley Periodicals, Inc.

  2. Radiation dose reduction without compromise to image quality by alterations of filtration and focal spot size in cerebral angiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Joon; Park, Min Keun; Jung, Da Eun; Kang, Jung Han; Kim, Byung Moon [Dept. of Radiology, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2017-08-01

    Different angiographic protocols may influence the radiation dose and image quality. In this study, we aimed to investigate the effects of filtration and focal spot size on radiation dose and image quality for diagnostic cerebral angiography using an in-vitro model and in-vivo patient groups. Radiation dose and image quality were analyzed by varying the filtration and focal spot size on digital subtraction angiography exposure protocols (1, inherent filtration + large focus; 2, inherent + small; 3, copper + large; 4, copper + small). For the in-vitro analysis, a phantom was used for comparison of radiation dose. For the in-vivo analysis, bilateral paired injections, and patient cohort groups were compared for radiation dose and image quality. Image quality analysis was performed in terms of contrast, sharpness, noise, and overall quality. In the in-vitro analysis, the mean air kerma (AK) and dose area product (DAP)/frame were significantly lower with added copper filtration (protocols 3 and 4). In the in-vivo bilateral paired injections, AK and DAP/frame were significantly lower with filtration, without significant difference in image quality. The patient cohort groups with added filtration (protocols 3 and 4) showed significant reduction of total AK and DAP/patient without compromise to the image quality. Variations in focal spot size showed no significant differences in radiation dose and image quality. Addition of filtration for angiographic exposure studies can result in significant total radiation dose reduction without loss of image quality. Focal spot size does not influence radiation dose and image quality. The routine angiographic protocol should be judiciously investigated and implemented.

  3. Form Follows Function. A new approach to determining vessel function

    Directory of Open Access Journals (Sweden)

    Vincent van der Veen

    2018-05-01

    Full Text Available In this article I present a theoretical model for assigning functions to categories of Roman ceramics. This model was designed to make broad statements about assemblages that are too large to analyse in detail. It is therefore based on the 'ideal use' of a vessel - i.e. the function the potter had in mind when he chose the clay, temper, forming techniques and so on - rather than 'non-ideal' or actual use. Characteristics considered are, among others, shape, size, weight, surface treatment and wall thickness. Seven distinct functions have been identified, taking the inherent multi-functionality of certain vessels into account. In many cases an individual vessel type will be suitable for more than one function. In a case study the commonly made functional distinction between smooth-tempered one-handled flagons (kruiken as tableware and two-handled flagons (kruikamforen as storage vessels is challenged. Furthermore, differences in their deposition within both grave and settlement assemblages are explored.

  4. Evaluation of image quality on a per-patient, per-vessel, and per-segment basis by noninvasive coronary angiography with 64-section computed tomography. Dual-source versus single-source computed tomography

    International Nuclear Information System (INIS)

    Nakashima, Yoshiteru; Okada, Munemasa; Washida, Yasuo; Miura, Toshiro; Fujimura, Tatsuo; Nao, Tomoko; Matsunaga, Naofumi

    2011-01-01

    The purpose of this study was to evaluate the image quality (IQ) of dual-source CT (DSCT) versus single-source CT (SSCT). A total of 100 patients underwent 64-section CT coronary angiography (50 DSCT, 50 SSCT). Three observers evaluated the IQ of each coronary segment using a four-point scale (1, excellent; 2, good; 3, fair; 4, no assessment). The IQ of DSCT coronary angiography was compared with SSCT coronary angiography on a per-patient, per-vessel, and per-segment basis using the chi-squared test. The DSCT image quality score (IQS) was significantly lower on a per-patient basis and per-vessel basis for all vessels and on a per-segment basis for some segments (1, 2, 4PD, 4AV, 7, 9, 11, 12, 13) compared with SSCT. The DSCT IQS was significantly lower for certain segments (2, 4PD, 11, 13) with high heart rates (≥70 beats/min). The DSCT IQS was significantly lower for certain segments (1, 2, 3, 4PD, 4AV, 7, 8, 9, 10, 12, 13) with low heart rates (<70 beats/min). DSCT showed a significantly better IQ than SSCT, especially in patients with low heart rates. (author)

  5. Stability, structure and scale: improvements in multi-modal vessel extraction for SEEG trajectory planning.

    Science.gov (United States)

    Zuluaga, Maria A; Rodionov, Roman; Nowell, Mark; Achhala, Sufyan; Zombori, Gergely; Mendelson, Alex F; Cardoso, M Jorge; Miserocchi, Anna; McEvoy, Andrew W; Duncan, John S; Ourselin, Sébastien

    2015-08-01

    Brain vessels are among the most critical landmarks that need to be assessed for mitigating surgical risks in stereo-electroencephalography (SEEG) implantation. Intracranial haemorrhage is the most common complication associated with implantation, carrying significantly associated morbidity. SEEG planning is done pre-operatively to identify avascular trajectories for the electrodes. In current practice, neurosurgeons have no assistance in the planning of electrode trajectories. There is great interest in developing computer-assisted planning systems that can optimise the safety profile of electrode trajectories, maximising the distance to critical structures. This paper presents a method that integrates the concepts of scale, neighbourhood structure and feature stability with the aim of improving robustness and accuracy of vessel extraction within a SEEG planning system. The developed method accounts for scale and vicinity of a voxel by formulating the problem within a multi-scale tensor voting framework. Feature stability is achieved through a similarity measure that evaluates the multi-modal consistency in vesselness responses. The proposed measurement allows the combination of multiple images modalities into a single image that is used within the planning system to visualise critical vessels. Twelve paired data sets from two image modalities available within the planning system were used for evaluation. The mean Dice similarity coefficient was 0.89 ± 0.04, representing a statistically significantly improvement when compared to a semi-automated single human rater, single-modality segmentation protocol used in clinical practice (0.80 ± 0.03). Multi-modal vessel extraction is superior to semi-automated single-modality segmentation, indicating the possibility of safer SEEG planning, with reduced patient morbidity.

  6. Defining an adequate sample of earlywood vessels for retrospective injury detection in diffuse-porous species.

    Directory of Open Access Journals (Sweden)

    Estelle Arbellay

    Full Text Available Vessels of broad-leaved trees have been analyzed to study how trees deal with various environmental factors. Cambial injury, in particular, has been reported to induce the formation of narrower conduits. Yet, little or no effort has been devoted to the elaboration of vessel sampling strategies for retrospective injury detection based on vessel lumen size reduction. To fill this methodological gap, four wounded individuals each of grey alder (Alnus incana (L. Moench and downy birch (Betula pubescens Ehrh. were harvested in an avalanche path. Earlywood vessel lumina were measured and compared for each tree between the injury ring built during the growing season following wounding and the control ring laid down the previous year. Measurements were performed along a 10 mm wide radial strip, located directly next to the injury. Specifically, this study aimed at (i investigating the intra-annual duration and local extension of vessel narrowing close to the wound margin and (ii identifying an adequate sample of earlywood vessels (number and intra-ring location of cells attesting to cambial injury. Based on the results of this study, we recommend analyzing at least 30 vessels in each ring. Within the 10 mm wide segment of the injury ring, wound-induced reduction in vessel lumen size did not fade with increasing radial and tangential distances, but we nevertheless advise favoring early earlywood vessels located closest to the injury. These findings, derived from two species widespread across subarctic, mountainous, and temperate regions, will assist retrospective injury detection in Alnus, Betula, and other diffuse-porous species as well as future related research on hydraulic implications after wounding.

  7. Quantitative analysis of artifacts in 4D DSA: the relative contributions of beam hardening and scatter to vessel dropout behind highly attenuating structures

    Science.gov (United States)

    Hermus, James; Szczykutowicz, Timothy P.; Strother, Charles M.; Mistretta, Charles

    2014-03-01

    When performing Computed Tomographic (CT) image reconstruction on digital subtraction angiography (DSA) projections, loss of vessel contrast has been observed behind highly attenuating anatomy, such as dental implants and large contrast filled aneurysms. Because this typically occurs only in a limited range of projection angles, the observed contrast time course can potentially be altered. In this work, we have developed a model for acquiring DSA projections that models both the polychromatic nature of the x-ray spectrum and the x-ray scattering interactions to investigate this problem. In our simulation framework, scatter and beam hardening contributions to vessel dropout can be analyzed separately. We constructed digital phantoms with large clearly defined regions containing iodine contrast, bone, soft issue, titanium (dental implants) or combinations of these materials. As the regions containing the materials were large and rectangular, when the phantoms were forward projected, the projections contained uniform regions of interest (ROI) and enabled accurate vessel dropout analysis. Two phantom models were used, one to model the case of a vessel behind a large contrast filled aneurysm and the other to model a vessel behind a dental implant. Cases in which both beam hardening and scatter were turned off, only scatter was turned on, only beam hardening was turned on, and both scatter and beam hardening were turned on, were simulated for both phantom models. The analysis of this data showed that the contrast degradation is primarily due to scatter. When analyzing the aneurysm case, 90.25% of the vessel contrast was lost in the polychromatic scatter image, however only 50.5% of the vessel contrast was lost in the beam hardening only image. When analyzing the teeth case, 44.2% of the vessel contrast was lost in the polychromatic scatter image and only 26.2% of the vessel contrast was lost in the beam hardening only image.

  8. Blood flow determinations utilizing digital densitometry

    International Nuclear Information System (INIS)

    Lois, F.; Mankovich, N.J.; Gomes, A.S.

    1987-01-01

    A method of obtaining relative and absolute blood flow measurements from digital densitometry was evaluated with a simulated vessel phantom and a hydrodynamic model. A digital vascular imaging system capable of acquisition in 512 2 and 1024 2 mode was used. Relative and absolute blood flow were measured using parameters derived from the densitometric curve. Since application of densitometric data to absolute flow measurements requires the vessel diameter, an algorithm for vessel size determination was created. Gray scale changes were demonstrated to be linearly related to contrast concentration. The variance of vessel size determination was significantly different in all combinations of 1024 2 and 512 2 imaging with 15 cm or 35 cm field size. The error in vessel size determination was significantly less using the larger 1024 2 matrix and the smaller 15 cm image intensifier field size, as shown by the smaller variance. In relative flow determinations, there was good correlation between the flow and four parameters of the densitometric curve with no significant differences between 512 2 and 1024 2 imaging. Absolute flow determinations had slightly lower correlation to actual flow but were not significantly different from relative flow determinations. Relative and absolute blood flow determinations can be performed adequately with either 512 2 or 1024 2 imaging. The increased accuracy in vessel size determination with 1024 2 imaging makes this high resolution system potentially perferable to determine absolute blood flow. (orig.)

  9. Molecular nuclear imaging of tumoral angio genesis using a rgd-containing tracer, Raft-RGD, targeted at the neo vessel-specific integrin αvβ3

    International Nuclear Information System (INIS)

    Sancey, L.

    2006-06-01

    Tumoral neo-angio genesis targeting is currently a major field of research for the diagnostic and treatment of solid tumors. Endothelial cells from neo vessels over express several specific markers such as the α v β 3 integrin, which binds RGD (-Arg-Gly-Asp-)- containing peptides. We evaluated the potential of a novel radiotracer - RAFT-RGD - for the molecular nuclear imaging of neo vessels. In vitro, the coupling of 4 c(RGDfK) to the RAFT platform resulted in an increased cellular uptake of the tracer by α v β 3 positive cells when compared to c(RGDfK). Furthermore, RAFTRGD has a higher affinity than c(RGDfK) and similar properties for angio genesis inhibition. In vivo, both α v β 3 positive and negative tumors were visible by non invasive whole body planar and tomographic imaging from 30 min to 24 h post-injection, using a gamma camera dedicated to small animal imaging. Despite a lack of significant contrast improvement compare with c(RGDfK), RAFT-RGD could represent a promising tracer for tumoral angio genesis since it could provide invaluable information about tumor development and treatment efficacy in Nuclear Medicine departments. Furthermore, thanks to its chemical structure, RAFT-RGD can be labelled with a variety of radioisotopes including γ and β - emitters, allowing interesting therapeutical applications such as internal targeted radiotherapy. (author)

  10. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Conventional ultrasound displays the images in thin, ...

  11. Acoustic isolation vessel for measurement of the background noise in microphones

    Science.gov (United States)

    Ngo, Kim C. T.; Zuckerwar, Allan J.

    1993-01-01

    An acoustic isolation vessel has been developed to measure the background noise in microphones. The test microphone is installed in an inner vessel, which is suspended within an outer vessel, and the intervening air space is evacuated to a high vacuum. An analytical expression for the transmission coefficient is derived, based on a five-media model, and compared to experiment. At an isolation vacuum of 5 x 10 exp -6 Torr the experimental transmission coefficient was found to be lower than -155 dB at frequencies ranging from 40 to 1200 Hz. Measurements of the A-weighted noise levels of commercial condenser microphones of four different sizes show good agreement with published values.

  12. 33 CFR 90.3 - Pushing vessel and vessel being pushed: Composite unit.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Pushing vessel and vessel being... HOMELAND SECURITY INLAND NAVIGATION RULES INLAND RULES: INTERPRETATIVE RULES § 90.3 Pushing vessel and vessel being pushed: Composite unit. Rule 24(b) of the Inland Rules states that when a pushing vessel and...

  13. 33 CFR 82.3 - Pushing vessel and vessel being pushed: Composite unit.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Pushing vessel and vessel being... HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES 72 COLREGS: INTERPRETATIVE RULES § 82.3 Pushing vessel and vessel being pushed: Composite unit. Rule 24(b) of the 72 COLREGS states that when a pushing vessel and a...

  14. In-vessel calibration of the imaging diagnostics for the real-time protection of the JET ITER-like wall

    Energy Technology Data Exchange (ETDEWEB)

    Huber, V., E-mail: V.Huber@fz-juelich.de [Forschungszentrum Jülich GmbH, Supercomputing Centre, 52425 Jülich (Germany); Huber, A.; Mertens, Ph.; Sergienko, G. [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung—Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich (Germany); Kinna, D.; Balboa, I.; Collins, S.; Conway, N.; Maggi, C. F.; Matthews, G. F.; Meigs, A. G.; Price, M.; Silburn, S.; Zastrow, K.-D. [CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Drewelow, P. [MPI für Plasmaphysik, Greifswald (Germany); Wynn, A. [York Plasma Institute, University of York, Heslington, York YO10 5DD (United Kingdom)

    2016-11-15

    The in situ absolute calibration of the JET real-time protection imaging system has been performed for the first time by means of radiometric light source placed inside the JET vessel and operated by remote handling. High accuracy of the calibration is confirmed by cross-validation of the near infrared (NIR) cameras against each other, with thermal IR cameras, and with the beryllium evaporator, which lead to successful protection of the JET first wall during the last campaign. The operation temperature ranges of NIR protection cameras for the materials used on JET are Be 650-1600 °C, W coating 600-1320 °C, and W 650-1500 °C.

  15. A mathematical model for pressure-based organs behaving as biological pressure vessels.

    Science.gov (United States)

    Casha, Aaron R; Camilleri, Liberato; Gauci, Marilyn; Gatt, Ruben; Sladden, David; Chetcuti, Stanley; Grima, Joseph N

    2018-04-26

    We introduce a mathematical model that describes the allometry of physical characteristics of hollow organs behaving as pressure vessels based on the physics of ideal pressure vessels. The model was validated by studying parameters such as body and organ mass, systolic and diastolic pressures, internal and external dimensions, pressurization energy and organ energy output measurements of pressure-based organs in a wide range of mammals and birds. Seven rules were derived that govern amongst others, lack of size efficiency on scaling to larger organ sizes, matching organ size in the same species, equal relative efficiency in pressurization energy across species and direct size matching between organ mass and mass of contents. The lung, heart and bladder follow these predicted theoretical relationships with a similar relative efficiency across various mammalian and avian species; an exception is cardiac output in mammals with a mass exceeding 10kg. This may limit massive body size in mammals, breaking Cope's rule that populations evolve to increase in body size over time. Such a limit was not found in large flightless birds exceeding 100kg, leading to speculation about unlimited dinosaur size should dinosaurs carry avian-like cardiac characteristics. Copyright © 2018. Published by Elsevier Ltd.

  16. Wide-field absolute transverse blood flow velocity mapping in vessel centerline

    Science.gov (United States)

    Wu, Nanshou; Wang, Lei; Zhu, Bifeng; Guan, Caizhong; Wang, Mingyi; Han, Dingan; Tan, Haishu; Zeng, Yaguang

    2018-02-01

    We propose a wide-field absolute transverse blood flow velocity measurement method in vessel centerline based on absorption intensity fluctuation modulation effect. The difference between the light absorption capacities of red blood cells and background tissue under low-coherence illumination is utilized to realize the instantaneous and average wide-field optical angiography images. The absolute fuzzy connection algorithm is used for vessel centerline extraction from the average wide-field optical angiography. The absolute transverse velocity in the vessel centerline is then measured by a cross-correlation analysis according to instantaneous modulation depth signal. The proposed method promises to contribute to the treatment of diseases, such as those related to anemia or thrombosis.

  17. Superresolution Imaging of Aquaporin-4 Cluster Size in Antibody-Stained Paraffin Brain Sections.

    Science.gov (United States)

    Smith, Alex J; Verkman, Alan S

    2015-12-15

    The water channel aquaporin-4 (AQP4) forms supramolecular clusters whose size is determined by the ratio of M1- and M23-AQP4 isoforms. In cultured astrocytes, differences in the subcellular localization and macromolecular interactions of small and large AQP4 clusters results in distinct physiological roles for M1- and M23-AQP4. Here, we developed quantitative superresolution optical imaging methodology to measure AQP4 cluster size in antibody-stained paraffin sections of mouse cerebral cortex and spinal cord, human postmortem brain, and glioma biopsy specimens. This methodology was used to demonstrate that large AQP4 clusters are formed in AQP4(-/-) astrocytes transfected with only M23-AQP4, but not in those expressing only M1-AQP4, both in vitro and in vivo. Native AQP4 in mouse cortex, where both isoforms are expressed, was enriched in astrocyte foot-processes adjacent to microcapillaries; clusters in perivascular regions of the cortex were larger than in parenchymal regions, demonstrating size-dependent subcellular segregation of AQP4 clusters. Two-color superresolution imaging demonstrated colocalization of Kir4.1 with AQP4 clusters in perivascular areas but not in parenchyma. Surprisingly, the subcellular distribution of AQP4 clusters was different between gray and white matter astrocytes in spinal cord, demonstrating regional specificity in cluster polarization. Changes in AQP4 subcellular distribution are associated with several neurological diseases and we demonstrate that AQP4 clustering was preserved in a postmortem human cortical brain tissue specimen, but that AQP4 was not substantially clustered in a human glioblastoma specimen despite high-level expression. Our results demonstrate the utility of superresolution optical imaging for measuring the size of AQP4 supramolecular clusters in paraffin sections of brain tissue and support AQP4 cluster size as a primary determinant of its subcellular distribution. Copyright © 2015 Biophysical Society

  18. Carotid artery stenosis: Performance of advanced vessel analysis software in evaluating CTA

    International Nuclear Information System (INIS)

    Tsiflikas, Ilias; Biermann, Christina; Thomas, Christoph; Ketelsen, Dominik; Claussen, Claus D.; Heuschmid, Martin

    2012-01-01

    Objectives: The aim of this study was to evaluate time efficiency and diagnostic reproducibility of an advanced vessel analysis software for diagnosis of carotid artery stenosis. Material and methods: 40 patients with suspected carotid artery stenosis received head and neck DE-CTA as part of their pre-interventional workup. Acquired data were evaluated by 2 independent radiologists. Stenosis grading was performed by MPR eyeballing with freely adjustable MPRs and with a preliminary prototype of the meanwhile available client-server and advanced visualization software syngo.via CT Vascular (Siemens Healthcare, Erlangen, Germany). Stenoses were graded according to the following 5 categories: I: 0%, II: 1–50%, III: 51–69%, IV: 70–99% and V: total occlusion. Furthermore, time to diagnosis for each carotid artery was recorded. Results: Both readers achieved very good specificity values and good respectively very good sensitivity values without significant differences between both reading methods. Furthermore, there was a very good correlation between both readers for both reading methods without significant differences (kappa value: standard image interpretation k = 0.809; advanced vessel analysis software k = 0.863). Using advanced vessel analysis software resulted in a significant time saving (p < 0.0001) for both readers. Time to diagnosis could be decreased by approximately 55%. Conclusions: Advanced vessel analysis application CT Vascular of the new imaging software syngo.via (Siemens Healthcare, Forchheim, Germany) provides a high rate of reproducibility in assessment of carotid artery stenosis. Furthermore a significant time saving in comparison to standard image interpretation is achievable

  19. Carotid artery stenosis: Performance of advanced vessel analysis software in evaluating CTA

    Energy Technology Data Exchange (ETDEWEB)

    Tsiflikas, Ilias, E-mail: ilias.tsiflikas@med.uni-tuebingen.de [University Hospital of Tuebingen, Diagnostic and Interventional Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Biermann, Christina, E-mail: christina.biermann@siemens.com [University Hospital of Tuebingen, Diagnostic and Interventional Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Siemens AG, Siemens Healthcare Consulting, Allee am Röthelheimpark 3A, 91052 Erlangen (Germany); Thomas, Christoph, E-mail: christoph.thomas@med.uni-tuebingen.de [University Hospital of Tuebingen, Diagnostic and Interventional Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Ketelsen, Dominik, E-mail: dominik.ketelsen@med.uni-tuebingen.de [University Hospital of Tuebingen, Diagnostic and Interventional Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Claussen, Claus D., E-mail: claus.claussen@med.uni-tuebingen.de [University Hospital of Tuebingen, Diagnostic and Interventional Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Heuschmid, Martin, E-mail: martin.heuschmid@med.uni-tuebingen.de [University Hospital of Tuebingen, Diagnostic and Interventional Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)

    2012-09-15

    Objectives: The aim of this study was to evaluate time efficiency and diagnostic reproducibility of an advanced vessel analysis software for diagnosis of carotid artery stenosis. Material and methods: 40 patients with suspected carotid artery stenosis received head and neck DE-CTA as part of their pre-interventional workup. Acquired data were evaluated by 2 independent radiologists. Stenosis grading was performed by MPR eyeballing with freely adjustable MPRs and with a preliminary prototype of the meanwhile available client-server and advanced visualization software syngo.via CT Vascular (Siemens Healthcare, Erlangen, Germany). Stenoses were graded according to the following 5 categories: I: 0%, II: 1–50%, III: 51–69%, IV: 70–99% and V: total occlusion. Furthermore, time to diagnosis for each carotid artery was recorded. Results: Both readers achieved very good specificity values and good respectively very good sensitivity values without significant differences between both reading methods. Furthermore, there was a very good correlation between both readers for both reading methods without significant differences (kappa value: standard image interpretation k = 0.809; advanced vessel analysis software k = 0.863). Using advanced vessel analysis software resulted in a significant time saving (p < 0.0001) for both readers. Time to diagnosis could be decreased by approximately 55%. Conclusions: Advanced vessel analysis application CT Vascular of the new imaging software syngo.via (Siemens Healthcare, Forchheim, Germany) provides a high rate of reproducibility in assessment of carotid artery stenosis. Furthermore a significant time saving in comparison to standard image interpretation is achievable.

  20. High-resolution intracranial vessel wall MRI in an elderly asymptomatic population: comparison of 3T and 7T

    Energy Technology Data Exchange (ETDEWEB)

    Harteveld, Anita A.; Kolk, Anja G. van der; Dieleman, Nikki; Siero, Jeroen C.W.; Luijten, Peter R.; Zwanenburg, Jaco J.M.; Hendrikse, Jeroen [University Medical Center Utrecht, Department of Radiology, Postbox 85500, Utrecht (Netherlands); Worp, H.B. van der; Frijns, Catharina J.M. [University Medical Center Utrecht, Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, Utrecht (Netherlands); Kuijf, Hugo J. [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands)

    2017-04-15

    Several intracranial vessel wall sequences have been described in recent literature, with either 3-T or 7-T magnetic resonance imaging (MRI). In the current study, we compared 3-T and 7-T MRI in visualising both the intracranial arterial vessel wall and vessel wall lesions. Twenty-one elderly asymptomatic volunteers were scanned by 3-T and 7-T MRI with an intracranial vessel wall sequence, both before and after contrast administration. Two raters scored image quality, and presence and characteristics of vessel wall lesions. Vessel wall visibility was equal or significantly better at 7 T for the studied arterial segments, even though there were more artefacts hampering assessment. The better visualisation of the vessel wall at 7 T was most prominent in the proximal anterior cerebral circulation and the posterior cerebral artery. In the studied elderly asymptomatic population, 48 vessel-wall lesions were identified at 3 T, of which 7 showed enhancement. At 7 T, 79 lesions were identified, of which 29 showed enhancement. Seventy-one percent of all 3-T lesions and 59 % of all 7-T lesions were also seen at the other field strength. Despite the large variability in detected lesions at both field strengths, we believe 7-T MRI has the highest potential to identify the total burden of intracranial vessel wall lesions. (orig.)

  1. Medical image compression based on vector quantization with variable block sizes in wavelet domain.

    Science.gov (United States)

    Jiang, Huiyan; Ma, Zhiyuan; Hu, Yang; Yang, Benqiang; Zhang, Libo

    2012-01-01

    An optimized medical image compression algorithm based on wavelet transform and improved vector quantization is introduced. The goal of the proposed method is to maintain the diagnostic-related information of the medical image at a high compression ratio. Wavelet transformation was first applied to the image. For the lowest-frequency subband of wavelet coefficients, a lossless compression method was exploited; for each of the high-frequency subbands, an optimized vector quantization with variable block size was implemented. In the novel vector quantization method, local fractal dimension (LFD) was used to analyze the local complexity of each wavelet coefficients, subband. Then an optimal quadtree method was employed to partition each wavelet coefficients, subband into several sizes of subblocks. After that, a modified K-means approach which is based on energy function was used in the codebook training phase. At last, vector quantization coding was implemented in different types of sub-blocks. In order to verify the effectiveness of the proposed algorithm, JPEG, JPEG2000, and fractal coding approach were chosen as contrast algorithms. Experimental results show that the proposed method can improve the compression performance and can achieve a balance between the compression ratio and the image visual quality.

  2. Recent development for inservice inspection of reactor pressure vessels

    International Nuclear Information System (INIS)

    Fischer, K.; Engl, G.; Rathgeb, W.; Heumueller, R.

    1991-01-01

    The German Nuclear Code (KTA-rules) requires a full scope inservice inspection (ISI) of reactor pressure vessels within a period of four years. This has a remarkable influence on plant operation and economy. Therefore, the development of advanced inspection equipment and techniques is directed not only to the enhancement of defect detectability and flaw sizing capabilities but also to reducing inspection times. A new manipulator system for PWR vessels together with fast data processing reduces the time for ISI of modern RPVs to 7 days. A new multichannel UT-system based on ALOK principle offers increased ultrasonic information with comfortable and rapid evaluation and presentation of results together with enhanced sizing capabilities. For specific inspection problems characterized by geometrical complexity the application of phased array probes in connection with UT-tomography provides improved ultrasonic information together with a streamlined manipulator principle and simplification of set up and tear down at the component which results in considerable reduction of radiation exposure. (orig.)

  3. Vessel wall MRI of the thoracic aorta: correlation to histology and transesophageal ultrasound. Preliminary results

    International Nuclear Information System (INIS)

    Abolmaali, N.; Schick, C.; Thalhammer, A.; Schmitt, J.; Vogl, T.J.; Langenfeld, M.; Schaechinger, V.; Krahforst, R.; Schulze, T.

    2002-01-01

    Purpose: To visualise the vessel wall of the descending thoracic aorta using magnetic resonance imaging. To evaluate the diagnostic potential of tailored T 1 -weighted sequences with contrast enhancement to assess systemic atherosclerotic disease. Methods: This study was performed on a clinical 1.5 Tesla scanner using a gradient strength of 30 mT/m and the phased array spine coil. A cadaver was examined to optimise a magnetic resonance imaging (MRI) protocol to evaluate atherosclerotic aortic wall disease. The acquired MR images were compared to gross specimens and histology. Subsequently seven patients who had undergone transesophageal ultrasound (TEU) with detailed assessment of the descending thoracic aorta were examined with MRI. The optimised protocol included untriggered and fat suppressed T 2 -weighted turbo spin echo sequences and ECG-triggered and fat suppressed T 1 -weighted spin echo sequences before and after iv administration of Gd-DTPA. Findings of the MR images were compared to the results of TEU. Contrast enhancement measurements were performed in normal and thickened vessel wall segments. Results: For the cadaver study a good correlation of the degree of vessel wall thickening and the extent of plaque imaged with the applied MR protocol was found. Tissue characterisation was limited due to post mortem changes. In vivo ECG-triggered T 1 -weighted images showed good correlation to TEU in terms of vessel wall thickness and plaque extension as verified by means of consensus reading. Differentiation of the plaque components fat, calcium and fibrous tissue was possible. In thickened aortic wall segments and fibrous caps a mean contrast enhancement of 50.4%±23.5% was measurable while normal wall segments showed an enhancement of 6.7%±3.1%. (orig.) [de

  4. Application of high strength steel to nuclear reactor containment vessel

    International Nuclear Information System (INIS)

    Susukida, H.; Sato, M.; Takano, G.; Uebayashi, T.; Yoshida, K.

    1976-01-01

    Nuclear reactor containment vessels are becoming larger in size with the increase in the power generating capacity of nuclear power plants. For example, a containment vessel for a PWR power plant with an output of 1,000 MWe becomes an extremely large one if it is made of the conventional JIS SGV 49 (ASTM A 516 Gr. 70) steel plates less than 38 mm in thickness. In order to design the steel containment vessel within the conventional dimensional range, therefore, it is necessary to use a high strength steel having a higher tensile strength than SGV 49 steel, good weldability and a higher fracture toughness and moreover, possessing satisfactory properties without undergoing post-weld heat treatment. The authors conducted a series of verification tests on high strength steel developed by modifying the ASTM A 543 Grade B Class 1 steel with a view to adopting it as a material for the nuclear reactor containment vessels. As the result of evaluation of the test results from various angles, we confirmed that the high strength steel is quite suitable for the manufacture of nuclear reactor containment vessels. (auth.)

  5. Lesson of the month 1: Large vessel vasculitis - a diagnostic challenge and the role of 18-fluorodeoxyglucose positron emission tomography.

    Science.gov (United States)

    Allard, Andrew; Mootoo, Ramesh

    2017-07-01

    Large vessel vasculitis can pose a significant diagnostic challenge. It may be insidious in onset with the only presenting symptoms consisting of constitutional compromise. It may mimic other pathologies and the only serological abnormalities may be abnormal inflammatory markers. Conventional imaging modalities may not be diagnostic. We present a case of large vessel vasculitis that proved a significant diagnostic challenge with diagnosis established on 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) computerised tomography (CT) imaging. This is one of five cases of large vessel vasculitis that were diagnosed in the rheumatology department at our trust over a 12-month period with diagnosis established with the use of 18F-FDG PET CT. We discuss the advantages of 18F-FDG PET CT over more conventional imaging modalities in diagnosing large vessel vasculitis. © Royal College of Physicians 2017. All rights reserved.

  6. Impact of chemistry on Standard High Solids Vessel Design mixing

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-03-02

    The plan for resolving technical issues regarding mixing performance within vessels of the Hanford Waste Treatment Plant Pretreatment Facility directs a chemical impact study to be performed. The vessels involved are those that will process higher (e.g., 5 wt % or more) concentrations of solids. The mixing equipment design for these vessels includes both pulse jet mixers (PJM) and air spargers. This study assesses the impact of feed chemistry on the effectiveness of PJM mixing in the Standard High Solids Vessel Design (SHSVD). The overall purpose of this study is to complement the Properties that Matter document in helping to establish an acceptable physical simulant for full-scale testing. The specific objectives for this study are (1) to identify the relevant properties and behavior of the in-process tank waste that control the performance of the system being tested, (2) to assess the solubility limits of key components that are likely to precipitate or crystallize due to PJM and sparger interaction with the waste feeds, (3) to evaluate the impact of waste chemistry on rheology and agglomeration, (4) to assess the impact of temperature on rheology and agglomeration, (5) to assess the impact of organic compounds on PJM mixing, and (6) to provide the technical basis for using a physical-rheological simulant rather than a physical-rheological-chemical simulant for full-scale vessel testing. Among the conclusions reached are the following: The primary impact of precipitation or crystallization of salts due to interactions between PJMs or spargers and waste feeds is to increase the insoluble solids concentration in the slurries, which will increase the slurry yield stress. Slurry yield stress is a function of pH, ionic strength, insoluble solids concentration, and particle size. Ionic strength and chemical composition can affect particle size. Changes in temperature can affect SHSVD mixing through its effect on properties such as viscosity, yield stress, solubility

  7. Progress and Achievements on the R&D Activities for ITER Vacuum Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Nakahira, M. [Japan Atomic Energy Research Institute (JAERI); Koizumi, K. [Japan Atomic Energy Research Institute (JAERI); Takahashi, H. [Japan Atomic Energy Research Institute (JAERI); Onozuka, M. [ITER Joint Central Team, Garching, Germany; Ioki, K. [ITER Joint Central Team, Garching, Germany; Kuzumin, E. [D.V. Efremov Scientific Research Institute, St. Petersburg, Russia; Krylov, V. [D.V. Efremov Scientific Research Institute, St. Petersburg, Russia; Maslakowski, J. [Oak Ridge National Laboratory (ORNL); Nelson, Brad E [ORNL; Jones, L. [Max-Planck Institute, Garching, Germany; Danner, W. [Max-Planck Institute, Garching, Germany; Maisonnier, D. [Max-Planck Institute, Garching, Germany

    2001-01-01

    The ITER vacuum vessel (VV) is designed to be large double-walled structure with a D-shaped crosssection. The achievable fabrication tolerance of this structure was unknown due to the size and complexity of shape. The Full-scale Sector Model of ITER Vacuum Vessel, which was 15m in height, was fabricated and tested to obtain the fabrication and assembly tolerances. The model was fabricated within the target tolerance of 5mm and welding deformation during assembly operation was obtained. The port structure was also connected using remotized welding tools to demonstrate the basic maintenance activity. In parallel, the tests of advanced welding, cutting and inspection system were performed to improve the efficiency of fabrication and maintenance of the Vacuum Vessel. These activities show the feasibility of ITER Vacuum Vessel as feasible in a realistic way. This paper describes the major progress, achievement and latest status of the R&D activities on the ITER vacuum vessel.

  8. IMPACTS OF PATCH SIZE AND LAND COVER HETEROGENEITY ON THEMATIC IMAGE CLASSIFICATION ACCURACY

    Science.gov (United States)

    Landscape characteristics such as small patch size and land cover heterogeneity have been hypothesized to increase the likelihood of miss-classifying pixels during thematic image classification. However, there has been a lack of empirical evidence to support these hypotheses,...

  9. Remote Laser Diffraction Particle Size Distribution Analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Batcheller, Thomas Aquinas; Huestis, Gary Michael; Bolton, Steven Michael

    2001-03-01

    In support of a radioactive slurry sampling and physical characterization task, an “off-the-shelf” laser diffraction (classical light scattering) particle size analyzer was utilized for remote particle size distribution (PSD) analysis. Spent nuclear fuel was previously reprocessed at the Idaho Nuclear Technology and Engineering Center (INTEC—formerly recognized as the Idaho Chemical Processing Plant) which is on DOE’s INEEL site. The acidic, radioactive aqueous raffinate streams from these processes were transferred to 300,000 gallon stainless steel storage vessels located in the INTEC Tank Farm area. Due to the transfer piping configuration in these vessels, complete removal of the liquid can not be achieved. Consequently, a “heel” slurry remains at the bottom of an “emptied” vessel. Particle size distribution characterization of the settled solids in this remaining heel slurry, as well as suspended solids in the tank liquid, is the goal of this remote PSD analyzer task. A Horiba Instruments Inc. Model LA-300 PSD analyzer, which has a 0.1 to 600 micron measurement range, was modified for remote application in a “hot cell” (gamma radiation) environment. This technology provides rapid and simple PSD analysis, especially down in the fine and microscopic particle size regime. Particle size analysis of these radioactive slurries down in this smaller range was not previously achievable—making this technology far superior than the traditional methods used. Successful acquisition of this data, in conjunction with other characterization analyses, provides important information that can be used in the myriad of potential radioactive waste management alternatives.

  10. Diagnosis of hepatic encephalopathy with magentic resonance imaging

    International Nuclear Information System (INIS)

    Inoue, Etsuo; Narumi, Yoshifumi; Kadota, Tsuyoshi; Fujita, Makoto; Kuriyama, Keiko; Kuroda, Chikazumi

    1993-01-01

    Cranial magnetic resonance (MR) images were examined in 16 patients with liver cirrhosis. The findings of MR imaging were correlated with portal-systemic collateral vessel shown on angiograms. In 9 of 16 patients, basal ganglia was hyperintense compared with white matter on T1-weighted images. These 9 patients had portal-systemic collateral vessel 10 mm or more in diameter that was suppied by superior mesenteric vein (SMV), and 4 of the 9 patients had portal-systemic encephalopathy on angiograms. In the remaining 7 patients, no hyperintense lesions were seen in basal ganglia relative to white matter on T1-weighted images; angiography revealed that 2 patients had portal-systemic collateral vessel that was supplied by SMV but was 5 mm or less in diameter, 3 had bood supplies from splenic vein, and 2 had no collateral vessel. There was no change in signal intensity on T2-weighted images. In conclusion, a large portal-systemic collateral vessel supplied by SMV may be shown as a high intensity lesion in basal ganglia, thus making it possible to diagnose hepatic encephalopathy even if there was no psychoneurologic symptoms or signs. (N.K.)

  11. Human and nonhuman primate meninges harbor lymphatic vessels that can be visualized noninvasively by MRI.

    Science.gov (United States)

    Absinta, Martina; Ha, Seung-Kwon; Nair, Govind; Sati, Pascal; Luciano, Nicholas J; Palisoc, Maryknoll; Louveau, Antoine; Zaghloul, Kareem A; Pittaluga, Stefania; Kipnis, Jonathan; Reich, Daniel S

    2017-10-03

    Here, we report the existence of meningeal lymphatic vessels in human and nonhuman primates (common marmoset monkeys) and the feasibility of noninvasively imaging and mapping them in vivo with high-resolution, clinical MRI. On T2-FLAIR and T1-weighted black-blood imaging, lymphatic vessels enhance with gadobutrol, a gadolinium-based contrast agent with high propensity to extravasate across a permeable capillary endothelial barrier, but not with gadofosveset, a blood-pool contrast agent. The topography of these vessels, running alongside dural venous sinuses, recapitulates the meningeal lymphatic system of rodents. In primates, meningeal lymphatics display a typical panel of lymphatic endothelial markers by immunohistochemistry. This discovery holds promise for better understanding the normal physiology of lymphatic drainage from the central nervous system and potential aberrations in neurological diseases.

  12. Time-resolved echo-shared parallel MRA of the lung: observer preference study of image quality in comparison with non-echo-shared sequences

    International Nuclear Information System (INIS)

    Fink, C.; Puderbach, M.; Zaporozhan, J.; Plathow, C.; Kauczor, H.-U.; Ley, S.

    2005-01-01

    The aim of this study was to evaluate the image quality of time-resolved echo-shared parallel MRA of the lung. The pulmonary vasculature of nine patients (seven females, two males; median age: 44 years) with pulmonary disease was examined using a time-resolved MRA sequence combining echo sharing with parallel imaging (time-resolved echo-shared angiography technique, or TREAT). The sharpness of the vessel borders, conspicuousness of peripheral lung vessels, artifact level, and overall image quality of TREAT was assessed independently by four readers in a side-by-side comparison with non-echo-shared time-resolved parallel MRA data (pMRA) previously acquired in the same patients. Furthermore, the SNR of pulmonary arteries (PA) and veins (PV) achieved with both pulse sequences was compared. The mean voxel size of TREAT MRA was decreased by 24% compared with the non-echo-shared MRA. Regarding the sharpness of the vessel borders, conspicuousness of peripheral lung vessels, and overall image quality the TREAT sequence was rated superior in 75-76% of all cases. If the TREAT images were preferred over the pMRA images, the advantage was rated as major in 61-71% of all cases. The level of artifacts was not increased with the TREAT sequence. The mean interobserver agreement for all categories ranged between fair (artifact level) and good (overall image quality). The maximum SNR of TREAT did not differ from non-echo-shared parallel MRA (PA: TREAT: 273±45; pMRA: 280±71; PV: TREAT: 273±33; pMRA: 258±62). TREAT achieves a higher spatial resolution than non-echo-shared parallel MRA which is also perceived as an improved image quality. (orig.)

  13. Digital image evaluation for the determination of morphometric sizes for periodontal X-ray diagnosis and selective coronary angiography

    International Nuclear Information System (INIS)

    Barth, K.

    1982-01-01

    In its uses in the areas of periodontology and coronary angiography it is shown, how the digital image evaluation expands the possibilities of x-ray diagnosis and how it improves the objectivity and exactness of the evaluation. For the accomplishment of this task a detailed analysis of the morphological data is undertaken. The results of the analysis lead to a mathematical structure model. Based on this model the recognition and measuring of the object in an adaptive heuristic process is undertaken. In this case it dealt with a desmodontal split, whose change is indicated by a periodontal bone atrophy. The contour recognition is embedded in a newly created image processing system, which allows itself to be used generally and is shown using the presentation of coronary vessels as an example. The exactness of the automatic image evaluation in comparison to the measuring done by the doctor is discussed. (orig./TRV) [de

  14. Pocket Size Solid State FLASH and iPOD Drives for gigabyte storage, display and transfer of digital medical images: an introduction

    International Nuclear Information System (INIS)

    Sankaran, A.

    2008-01-01

    The transition of radiological imaging from analog to digital was closely followed by the development of the Picture Archiving and Communication (PACS) system. Concomitantly, multidimensional imaging ( 4D and 5D, for motion and functional studies on 3D images) have presented new challenges, particularly in handling gigabyte size images from CT, MRI and PET scanners, which generate thousands of images. The storage and analysis of these images necessitate expensive image workstations. This paper highlights the recent innovations in mass storage, display and transfer of images, using miniature/pocket size solid state FLASH and iPOD drives

  15. Use of positron emission tomography (PET) for the diagnosis of large-vessel vasculitis.

    Science.gov (United States)

    Loricera, J; Blanco, R; Hernández, J L; Martínez-Rodríguez, I; Carril, J M; Lavado, C; Jiménez, M; González-Vela, C; González-Gay, M Á

    2015-01-01

    The term vasculitis encompasses a heterogeneous group of diseases that share the presence of inflammatory infiltrates in the vascular wall. The diagnosis of large-vessel vasculitis is often a challenge because the presenting clinical features are nonspecific in many cases and they are often shared by different types of autoimmune and inflammatory diseases including other systemic vasculitides. Moreover, the pathogenesis of large-vessel vasculitis is not fully understood. Nevertheless, the advent of new imaging techniques has constituted a major breakthrough to establish an early diagnosis and a promising tool to monitor the follow-up of patients with largevessel vasculitis. This is the case of the molecular imaging with the combination of positron emission tomography with computed tomography (PET/CT) using different radiotracers, especially the (18)F-fluordeoxyglucose ((18)F-FDG). In this review we have focused on the contribution of (18)F-FDG PET in the diagnosis of large-vessel vasculitis. Copyright © 2015 Elsevier España, S.L.U. and SEMNIM. All rights reserved.

  16. Validation of the Simbionix PROcedure Rehearsal Studio sizing module : A comparison of software for endovascular aneurysm repair sizing and planning

    NARCIS (Netherlands)

    Velu, Juliëtte F.; Groot Jebbink, Erik; de Vries, Jean-Paul P.M.; Slump, Cornelis H.; Geelkerken, Robert H.

    2017-01-01

    An important determinant of successful endovascular aortic aneurysm repair is proper sizing of the dimensions of the aortic-iliac vessels. The goal of the present study was to determine the concurrent validity, a method for comparison of test scores, for EVAR sizing and planning of the recently

  17. Significance of 'Bridging vessel sign' on color Doppler ultrasound in diagnosis of uterine subserosal leiomyoma

    International Nuclear Information System (INIS)

    Lee, Jin Hee; Lee, Jung Hee; Sohn, Chul Ho; Woo, Seung Koo; Kim, Jung Sik

    2002-01-01

    To evaluate the usefulness of the 'bridging vessel sign' in differentiating uterine subserosal leiomyoma from other pelvic masses mimicking leiomyoma on color Doppler ultrasound. Histologically (n=58) and clinically (n=1) proven 59 masses from 55 women were included in this study. Histologic diagnoses included leiomyoma (n=32) and various kinds of other masses (n=27). On gray scale ultrasound, the size of tumor and presence of the ovaries were recorded. On color Doppler ultrasound, the presence of 'bridging vessel sign', which was defined as a linear vessel demonstrated between the mass and the uterus was documented. Uterine subserosal leiomyoma was diagnosed on the basis of finding this sign, and the diagnostic accuracy of this sign in differentiating subserosal leiomyoma from other pelvic tumors was calculated. In addition, the diagnostic accuracy of this sign combined with the visibility of theopsilateral ovary was compared. The size of subserosal leiomyomas ranged from 4.2 to 22.1 cm (mean, 8.3 cm) while the size of other pelvic masses, from 4.6 to 21.5 cm (mean, 9.6 cm). The 'bridging vessel sign' was demonstrated in thirty of 32 leiomyomas and in three of 27 other pelvis masses. The sensitivity, specificity, accuracy, positive predictive value, and negative value of the 'bridging vessel sign' in the diagnosis of subserosal leiomyoma were 93.8%, 99.9%, 91.5%, 90.9% and 92.3%, respectively. The detection of the ipsilateral ovary was possible in 14 of 30 women with leiomyomas and in four of 25 women with other pelvic masses. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of this finding in the diagnosis of subserosal leiomyoma were 46.7%, 84.0%, 63.6%, 77.8%, and 56.8%, respectively. 'Bridging vessel sign' can be an useful finding in the differential diagnosis of subserosal leiomyomas from other pelvic masses mimicking leiomyoma.

  18. Assessment of Radiation Embrittlement in Nuclear Reactor Pressure Vessel Surrogate Materials

    Science.gov (United States)

    Balzar, Davor

    2010-10-01

    The radiation-enhanced formation of small (1-2 nm) copper-rich precipitates (CRPs) is critical for the occurrence of embrittlement in nuclear-reactor pressure vessels. Small CRPs are coherent with the bcc matrix, which causes local matrix strain and interaction with the dislocation strain fields, thus impeding dislocation mobility. As CRPs grow, there is a critical size at which a phase transformation occurs, whereby the CRPs are no longer coherent with the matrix, and the strain is relieved. Diffraction-line-broadening analysis (DLBA) and small-angle neutron scattering (SANS) were used to characterize the precipitate formation in surrogate ferritic reactor-pressure vessel steels. The materials were aged for different times at elevated temperature to produce a series of specimens with different degrees of copper precipitation. SANS measurements showed that the precipitate size distribution broadens and shifts toward larger sizes as a function of ageing time. Mechanical hardness showed an increase with ageing time, followed by a decrease, which can be associated with the reduction in the number density as well as the loss of coherency at larger sizes. Inhomogeneous strain correlated with mechanical hardness.

  19. Vessel Operator System

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Operator cards are required for any operator of a charter/party boat and or a commercial vessel (including carrier and processor vessels) issued a vessel permit from...

  20. A NEW METHOD FOR ESTIMATING THE 3D SIZE-DISTRIBUTIONCURVE OF FRAGMENTED ROCKS OUT OF 2D IMAGES

    Directory of Open Access Journals (Sweden)

    Souhaïl Outal

    2011-05-01

    Full Text Available Image analysis of rock fragmentation is used in mines and quarries to control the quality of blasting. Obtained information is the particle-size-distribution curve relating volume-proportions to the sizes of fragments. Calculation by image analysis of this particle-size-distribution is carried out in several steps, and each step has its inherent limitations. We will focus in this paper on one of themost crucial steps: reconstructing the volumes (3D. For the 3D-step, we have noticed that, due to the current acquisition method, there is no correlation between the average grey level of surfaces of the fragments and their third dimension. Consequently volumes (3D as well as the sizes (1D has to be calculated indirectly from the extracted projected areas of the visible fragments of images. For this purpose, we have built in laboratory a set of images of fragmented rocks resulting from blasting. Moreover, several tests based on comparisons between image analysis and screening measurements were carried out. A new stereological method, based on the comparison of the densities of probability (histograms of the samemeasurements (with very weak covering and overlappingwas elaborated. It allows us to estimate correctly, for a given type of rock, two intrinsic laws weighing the projected areas distribution in order to predict the volumic distribution.

  1. Comprehending the structure of a vacuum vessel and in-vessel components of fusion machines. 1. Comprehending the vacuum vessel structure

    International Nuclear Information System (INIS)

    Onozuka, Masanori; Nakahira, Masataka

    2006-01-01

    The functions, conditions and structure of vacuum vessel using tokamak fusion machines are explained. The structural standard and code of vacuum vessel, process of vacuum vessel design, and design of ITER vacuum vessel are described. Production and maintenance of ultra high vacuum, confinement of radioactive materials, support of machines in vessel and electromagnetic force, radiation shield, plasma vertical stability, one-turn electric resistance, high temperature baking heat and remove of nuclear heat, reduce of troidal ripple, structural standard, features of safety of nuclear fusion machines, subjects of structural standard of fusion vacuum vessel, design flow of vacuum vessel, establishment of radial build, selections of materials, baking and cooling method, basic structure, structure of special parts, shield structure, and of support structure, and example of design of structure, ITER, are stated. (S.Y.)

  2. Storage vessel for radiation contaminated container

    International Nuclear Information System (INIS)

    Sakatani, Tadatsugu.

    1996-01-01

    In a storage vessel of the present invention, a plurality of radiation contaminated material containing bodies are vertically stacked in a cell chamber. Then, the storage vessel comprises a containing tube for containing a plurality of the containing bodies, cooling coils wound around the containing tube, a cooling medium circulating system connected to the cooling coils and circulating cooling medium, and a heat exchanger interposed to the cooling medium circulating system for removing heat of the cooling medium. Heat of the radioactive material containing bodies is transferred to cooling air and cooling coils by way of the container tube, thereby cooling the containing bodies. By the operation of circulating pumps in a cooling medium circulation system, the cooling medium circulates through a circulation channel comprising a cooling medium transfer pipes, cooling medium branching tubes, cooling coils and the heat exchanger, then heat of the cooling medium is transferred to a heat utilizing system by way of the heat exchanger to attain effective utilization of the heat. In this case, heat can be taken out stably even when the storage amount fluctuates and heat releasing amount is reduced, and improvement of heat transfer promotes the cooling of the containing bodies, which enables minimization of the size of the storage vessel. (T.M.)

  3. A study on the inclusion sizing using immersion ultrasonic C-scan imaging

    International Nuclear Information System (INIS)

    Chen, D; Xiao, H F; Li, M; Xu, J W

    2017-01-01

    Inclusion sizing, especially for large inclusions greater than 30μm provides important reference for metallurgical process control and fatigue life assessment of steel. Ultrasonic non-destructive testing (NDT) shows great advantages in detecting infrequently occurred large inclusions than eddy current, magnetic particle, microscopic or macroscopic examination procedures. In this paper, the performance of inclusion sizing by immersion ultrasonic C-scan imaging is studied numerically. A two-dimensional model that consists of spherically focused transducer, water couplant and steel with embedded inclusion is established and solved numerically by the finite element method. The signal intensity distributions of inclusion with different sizes are acquired and the effects of inclusion type, shape, orientation on signal intensity distribution are analysed. The results show that the 6dB-drop threshold has the smallest relative error compared with the 12dB-drop threshold and the full-drop threshold, which is better for determining inclusion size larger than 100μm. Experiment is also performed to validate the simulated results. (paper)

  4. Tissues segmentation based on multi spectral medical images

    Science.gov (United States)

    Li, Ya; Wang, Ying

    2017-11-01

    Each band image contains the most obvious tissue feature according to the optical characteristics of different tissues in different specific bands for multispectral medical images. In this paper, the tissues were segmented by their spectral information at each multispectral medical images. Four Local Binary Patter descriptors were constructed to extract blood vessels based on the gray difference between the blood vessels and their neighbors. The segmented tissue in each band image was merged to a clear image.

  5. Two micron pore size MCP-based image intensifiers

    Science.gov (United States)

    Glesener, John; Estrera, Joseph

    2010-02-01

    Image intensifiers (I2) have many advantages as detectors. They offer single photon sensitivity in an imaging format, they're light in weight and analog I2 systems can operate for hours on a single AA battery. Their light output is such as to exploit the peak in color sensitivity of the human eye. Until recent developments in CMOS sensors, they also were one of the highest resolution sensors available. The closest all solid state solution, the Texas Instruments Impactron chip, comes in a 1 megapixel format. Depending on the level of integration, an Impactron based system can consume 20 to 40 watts in a system configuration. In further investing in I2 technology, L-3 EOS determined that increasing I2 resolution merited a high priority. Increased I2 resolution offers the system user two desirable options: 1) increased detection and identification ranges while maintaining field-of-view (FOV) or 2) increasing FOV while maintaining the original system resolution. One of the areas where an investment in resolution is being made is in the microchannel plate (MCP). Incorporation of a 2 micron MCP into an image tube has the potential of increasing the system resolution of currently fielded systems. Both inverting and non-inverting configurations are being evaluated. Inverting tubes are being characterized in night vision goggle (NVG) and sights. The non-inverting 2 micron tube is being characterized for high resolution I2CMOS camera applications. Preliminary measurements show an increase in the MTF over a standard 5 micron pore size, 6 micron pitch plate. Current results will be presented.

  6. Efficacy study of the digital image processing with varying pixel size at A/D conversion of the chest radiograph

    Energy Technology Data Exchange (ETDEWEB)

    Inamoto, Kazuo; Tanaka, Shinichi; Miura, Takashi; Takahashi, Akira; Iwata, Tetsuya

    1984-12-01

    In the study for development of medical image archiving system, we made experiments in the field of conversion of a X-ray picture to a digital form. Three sets of chest radiograph were selected for the study of digitalization by reading different pixel size (150-300 m) in the method of A/D conversion using a drum scanner and again reconstructed to an analog form after D/A conversion. These copy films of different pixel size were shown and evaluated by 48 volunteer doctors to choose a favorite picture. It did not always follow that the most favorite picture was the finest one using the smallest pixel size. This discrepancy was further analyzed by measurement of a density histogram. By comparison studies of density curves in the same ROI of different pixel size pictures, it was concluded that their choices were dependent on not only fineness but also contrast of an output image after D/A conversion. Often better contrast picture was a key to the selection more than the pixel size. This indicates that digital storing radiographs will be possibly regenerated to the real image by the skillful operation of pixel size and contrast of a radiograph. The results will contribute to the process of recording analog X-ray picture by a digital form in the medical image archiving system.

  7. Vessel architecture in human knee cartilage in children: an in vivo susceptibility-weighted imaging study at 7 T.

    Science.gov (United States)

    Kolb, Alexander; Robinson, Simon; Stelzeneder, David; Schreiner, Markus; Chiari, Catharina; Windhager, Reinhard; Trattnig, Siegfried; Bohndorf, Klaus

    2018-02-26

    To evaluate the clinical feasibility of ultrahigh field 7-T SWI to visualize vessels and assess their density in the immature epiphyseal cartilage of human knee joints. 7-T SWI of 12 knees (six healthy volunteers, six patients with osteochondral abnormalities; mean age 10.7 years; 3 female, 9 male) were analysed by two readers, classifying intracartilaginous vessel densities (IVD) in three grades (no vessels, low IVD and high IVD) in defined femoral, tibial and patellar zones. Differences between patients and volunteers, IVDs in different anatomic locations, differences between cartilage overlying osteochondral abnormalities and corresponding normal zones, and differences in age groups were analysed. Interrater reliability showed moderate agreement between the two readers (κ = 0.58, p < 0.001). The comparison of IVDs between patients and volunteers revealed no significant difference (p = 0.706). The difference between zones in the cartilage overlying osteochondral abnormalities to corresponding normal zones showed no significant difference (p = 0.564). IVDs were related to anatomic location, with decreased IVDs in loading areas (p = 0.003). IVD was age dependent, with more vessels present in the younger participants (p = 0.001). The use of SWI in conjunction with ultrahigh field MRI makes the in vivo visualization of vessels in the growing cartilage of humans feasible, providing insights into the role of the vessel network in acquired disturbances. • SWI facilitates in vivo visualization of vessels in the growing human cartilage. • Interrater reliability of the intracartilaginous vessel grading was moderate. • Intracartilaginous vessel densities are dependent on anatomical location and age.

  8. Conjugate heat transfer analysis for in-vessel retention with external reactor vessel cooling

    International Nuclear Information System (INIS)

    Park, Jong-Woon; Bae, Jae-ho; Song, Hyuk-Jin

    2016-01-01

    Highlights: • A conjugate heat transfer analysis method is applied for in-vessel corium retention. • 3D heat diffusion has a formidable effect in alleviating focusing heat load from metallic layer. • The focusing heat load is decreased by about 2.5 times on the external surface. - Abstract: A conjugate heat transfer analysis method for the thermal integrity of a reactor vessel under external reactor vessel cooling conditions is developed to resolve light metal layer focusing effect issue for in-vessel retention. The method calculates steady-state three-dimensional temperature distribution of a reactor vessel using coupled conjugate heat transfer between in-vessel three-layered stratified corium (metallic pool, oxide pool and heavy metal and polar-angle dependent boiling heat transfer at the outer surface of a reactor vessel). The three-layer corium heat transfer model is utilizing lumped-parameter thermal-resistance circuit method. For the ex-vessel boiling boundary conditions, nucleate, transition and film boiling are considered. The thermal integrity of a reactor vessel is addressed in terms of heat flux at the outer-most nodes of the vessel and remaining thickness profile. The vessel three-dimensional heat conduction is validated against a commercial code. It is found that even though the internal heat flux from the metal layer goes far beyond critical heat flux (CHF) the heat flux from the outermost nodes of the vessel may be maintained below CHF due to massive vessel heat diffusion. The heat diffusion throughout the vessel is more pronounced for relatively low heat generation rate in an oxide pool. Parametric calculations are performed considering thermal conditions such as peak heat flux from a light metal layer, heat generation in an oxide pool and external boiling conditions. The major finding is that the most crucial factor for success of in-vessel retention is not the mass of the molten light metal above the oxide pool but the heat generation rate

  9. Radiology trainer. Torso, internal organs and vessels. 2. ed.

    International Nuclear Information System (INIS)

    Staebler, Axel; Erlt-Wagner, Birgit

    2013-01-01

    The radiology training textbook is based on case studies of the clinical experience, including radiological imaging and differential diagnostic discussion. The scope of this volume covers the torso, internal organs and vessels. The following issues are discussed: lungs, pleura, mediastinum; heart and vascular system; upper abdomen organs; gastrointestinal tract; urogenital system.

  10. Experimental investigation on the influence of instrument settings on pixel size and nonlinearity in SEM image formation

    DEFF Research Database (Denmark)

    Carli, Lorenzo; Genta, Gianfranco; Cantatore, Angela

    2010-01-01

    The work deals with an experimental investigation on the influence of three Scanning Electron Microscope (SEM) instrument settings, accelerating voltage, spot size and magnification, on the image formation process. Pixel size and nonlinearity were chosen as output parameters related to image...... quality and resolution. A silicon grating calibrated artifact was employed to investigate qualitatively and quantitatively, through a designed experiment approach, the parameters relevance. SEM magnification was found to account by far for the largest contribution on both parameters under consideration...

  11. Bounding the conservatism in flaw-related variables for pressure vessel integrity analyses

    International Nuclear Information System (INIS)

    Foulds, J.R.; Kennedy, E.L.

    1993-01-01

    The fracture mechanics-based integrity analysis of a pressure vessel, whether performed deterministically or probabilistically, requires use of one or more flaw-related input variables, such as flaw size, number of flaws, flaw location, and flaw type. The specific values of these variables are generally selected with the intent to ensure conservative predictions of vessel integrity. These selected values, however, are largely independent of vessel-specific inspection results, or are, at best, deduced by ''conservative'' interpretation of vessel-specific inspection results without adequate consideration of the pertinent inspection system performance (reliability). In either case, the conservatism associated with the flaw-related variables chosen for analysis remains examination (NDE) technology and the recently formulated ASME Code procedures for qualifying NDE system capability and performance (as applied to selected nuclear power plant components) now provides a systematic means of bounding the conservatism in flaw-related input variables for pressure vessel integrity analyses. This is essentially achieved by establishing probabilistic (risk)-based limits on the assigned variable values, dependent upon the vessel inspection results and on the inspection system unreliability. Described herein is this probabilistic method and its potential application to: (i) defining a vessel-specific ''reference'' flaw for calculating pressure-temperature limit curves in the deterministic evaluation of pressurized water reactor (PWR) reactor vessels, and (ii) limiting the flaw distribution input to a PWR reactor vessel-specific, probabilistic integrity analysis for pressurized thermal shock loads

  12. Research program plan: reactor vessels. Volume 1

    International Nuclear Information System (INIS)

    Vagins, M.; Taboada, A.

    1985-07-01

    The ability of the licensing staff of the NRC to make decisions concerning the present and continuing safety of nuclear reactor pressure vessels under both normal and abnormal operating conditions is dependent upon the existence of verified analysis methods and a solid background of applicable experimental data. It is the role of this program to provide both the analytical methods and the experimental data needed. Specifically, this program develops fracture mechanics analysis methods and design criteria for predicting the stress levels and flaw sizes required for crack initiation, propagation, and arrest in LWR pressure vessels under all known and postulated operations conditions. To do this, not only must the methods be developed but they must be experimentally validated. Further, the materials data necessary for input to these analytical methods must be developed. Thus, in addition to methods development and large scale experimental verification this program also develops data to show that slow-load fracture toughness, rapid-load fracture toughness, and crack arrest toughness obtained from small laboratory specimens are truly representative of the toughness characteristics of the material behavior in pressure vessels in both the unirradiated and the irradiated conditions

  13. Small vessel vasculitis History, classification, etiology, histopathology, clinic, diagnosis and treatment

    International Nuclear Information System (INIS)

    Iglesias Gamarra, Antonio; Matteson, Eric L; Restrepo, Jose Felix

    2007-01-01

    Small-vessel vasculitis is a convenient descriptor for a wide range of diseases characterized by vascular inflammation of the venules, capillaries, and/or arterioles with pleomorphic clinical manifestations. The classical clinical phenotype is leucocytoclastic vasculitis with palpable purpura, but manifestations vary widely depending upon the organs involved. Histopathologic examination in leucocytoclastic vasculitis reveals angiocentric segmental inflammation, fibrinoid necrosis, and a neutrophilic infiltrate around the blood vessel walls with erythrocyte extravasation. The etiology of small-vessel vasculitis is unknown in many cases, but in others, drugs, post viral syndromes, malignancy, primary vasculitis such as microscopic polyarteritis, and connective tissue disorders are associated, The diagnosis of small- vessel vasculitis relies on a thorough history and physical examination, as well as relevant antibody testing including antinuclear antibody and anti neutrophil cytoplasmic antibody, hepatitis B and C serologies, assessment of complement, immunoglobulins, blood count, serum creatinine liver function tests, urinalysis, radiographic imaging and biopsy. The treatment is based primarily on corticosteroid and immunosuppressive agents

  14. Medical Image Compression Based on Vector Quantization with Variable Block Sizes in Wavelet Domain

    Directory of Open Access Journals (Sweden)

    Huiyan Jiang

    2012-01-01

    Full Text Available An optimized medical image compression algorithm based on wavelet transform and improved vector quantization is introduced. The goal of the proposed method is to maintain the diagnostic-related information of the medical image at a high compression ratio. Wavelet transformation was first applied to the image. For the lowest-frequency subband of wavelet coefficients, a lossless compression method was exploited; for each of the high-frequency subbands, an optimized vector quantization with variable block size was implemented. In the novel vector quantization method, local fractal dimension (LFD was used to analyze the local complexity of each wavelet coefficients, subband. Then an optimal quadtree method was employed to partition each wavelet coefficients, subband into several sizes of subblocks. After that, a modified K-means approach which is based on energy function was used in the codebook training phase. At last, vector quantization coding was implemented in different types of sub-blocks. In order to verify the effectiveness of the proposed algorithm, JPEG, JPEG2000, and fractal coding approach were chosen as contrast algorithms. Experimental results show that the proposed method can improve the compression performance and can achieve a balance between the compression ratio and the image visual quality.

  15. The renin-angiotensin-aldosterone system in cerebral small vessel disease

    NARCIS (Netherlands)

    Brenner, D.; Labreuche, J.; Pico, F.; Scheltens, P.; Poirier, O.; Cambien, F.; Amarenco, P.

    2008-01-01

    Introduction: Cerebral small vessel disease (SVD) appears on magnetic resonance imaging (MRI) as leukoaraiosis (LA), état criblé (EC), and multiple lacunar infarctions (MLI). Although the pathophysiology of SVD is poorly understood, there is evidence of a genetic contribution. We sought to analyze

  16. Multimodal Microvascular Imaging Reveals that Selective Inhibition of Class I PI3K Is Sufficient to Induce an Antivascular Response

    Directory of Open Access Journals (Sweden)

    Deepak Sampath

    2013-07-01

    Full Text Available The phosphatidylinositol 3-kinase (PI3K pathway is a central mediator of vascular endothelial growth factor (VEGF-driven angiogenesis. The discovery of small molecule inhibitors that selectively target PI3K or PI3K and mammalian target of rapamycin (mTOR provides an opportunity to pharmacologically determine the contribution of these key signaling nodes in VEGF-A-driven tumor angiogenesis in vivo. This study used an array of microvascular imaging techniques to monitor the antivascular effects of selective class I PI3K, mTOR, or dual PI3K/ mTOR inhibitors in colorectal and prostate cancer xenograft models. Micro-computed tomography (micro-CT angiography, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI, vessel size index (VSI MRI, and DCE ultrasound (DCE-U/S were employed to quantitatively evaluate the vascular (structural and physiological response to these inhibitors. GDC-0980, a dual PI3K/mTOR inhibitor, was found to reduce micro-CT angiography vascular density, while VSI MRI demonstrated a significant reduction in vessel density and an increase in mean vessel size, consistent with a loss of small functional vessels and a substantial antivascular response. DCE-MRI showed that GDC-0980 produces a strong functional response by decreasing the vascular permeability/perfusion-related parameter, Ktrans. Interestingly, comparable antivascular effects were observed for both GDC-980 and GNE-490 (a selective class I PI3K inhibitor. In addition, mTOR-selective inhibitors did not affect vascular density, suggesting that PI3K inhibition is sufficient to generate structural changes, characteristic of a robust antivascular response. This study supports the use of noninvasive microvascular imaging techniques (DCE-MRI, VSI MRI, DCE-U/S as pharmacodynamic assays to quantitatively measure the activity of PI3K and dual PI3K/mTOR inhibitors in vivo.

  17. Influence of Spatial Resolution in Three-dimensional Cine Phase Contrast Magnetic Resonance Imaging on the Accuracy of Hemodynamic Analysis.

    Science.gov (United States)

    Fukuyama, Atsushi; Isoda, Haruo; Morita, Kento; Mori, Marika; Watanabe, Tomoya; Ishiguro, Kenta; Komori, Yoshiaki; Kosugi, Takafumi

    2017-10-10

    We aim to elucidate the effect of spatial resolution of three-dimensional cine phase contrast magnetic resonance (3D cine PC MR) imaging on the accuracy of the blood flow analysis, and examine the optimal setting for spatial resolution using flow phantoms. The flow phantom has five types of acrylic pipes that represent human blood vessels (inner diameters: 15, 12, 9, 6, and 3 mm). The pipes were fixed with 1% agarose containing 0.025 mol/L gadolinium contrast agent. A blood-mimicking fluid with human blood property values was circulated through the pipes at a steady flow. Magnetic resonance (MR) images (three-directional phase images with speed information and magnitude images for information of shape) were acquired using the 3-Tesla MR system and receiving coil. Temporal changes in spatially-averaged velocity and maximum velocity were calculated using hemodynamic analysis software. We calculated the error rates of the flow velocities based on the volume flow rates measured with a flowmeter and examined measurement accuracy. When the acrylic pipe was the size of the thoracicoabdominal or cervical artery and the ratio of pixel size for the pipe was set at 30% or lower, spatially-averaged velocity measurements were highly accurate. When the pixel size ratio was set at 10% or lower, maximum velocity could be measured with high accuracy. It was difficult to accurately measure maximum velocity of the 3-mm pipe, which was the size of an intracranial major artery, but the error for spatially-averaged velocity was 20% or less. Flow velocity measurement accuracy of 3D cine PC MR imaging for pipes with inner sizes equivalent to vessels in the cervical and thoracicoabdominal arteries is good. The flow velocity accuracy for the pipe with a 3-mm-diameter that is equivalent to major intracranial arteries is poor for maximum velocity, but it is relatively good for spatially-averaged velocity.

  18. ATLAS Supplier Award for the ECT Vacuum Vessels

    CERN Multimedia

    Jenni, P

    On 12 February the Netherlands firm Schelde Exotech was awarded the ATLAS Supplier Award for the construction of the two vacuum vessels for the ATLAS End- Cap Toroid (ECT) magnets. ATLAS Supplier Award ceremonies have now become something of a tradition. For the third consecutive year, ATLAS has given best supplier awards for the most exceptional contributors to the construction of the detector. The Netherlands firm Schelde Exotech has just received the award for the construction of the two vacuum vessels for the ECTs. With a diameter of 11 metres and a volume of 550 cubic metres, the ECT vacuum vessels are obviously impressive in scale. They consist of large aluminium plates and a stainless steel central bore tube. In order to obtain the required undulations, the firm had to develop a special assembly and welding technique. Despite the chambers' imposing size, a very high degree of precision has been achieved in their geometry. Moreover, the chambers, which were delivered in July 2002 to CERN, were built i...

  19. Can axial-based nodal size criteria be used in other imaging planes to accurately determine "enlarged" head and neck lymph nodes?

    Science.gov (United States)

    Bartlett, Eric S; Walters, Thomas D; Yu, Eugene

    2013-01-01

    Objective. We evaluate if axial-based lymph node size criteria can be applied to coronal and sagittal planes. Methods. Fifty pretreatment computed tomographic (CT) neck exams were evaluated in patients with head and neck squamous cell carcinoma (SCCa) and neck lymphadenopathy. Axial-based size criteria were applied to all 3 imaging planes, measured, and classified as "enlarged" if equal to or exceeding size criteria. Results. 222 lymph nodes were "enlarged" in one imaging plane; however, 53.2% (118/222) of these were "enlarged" in all 3 planes. Classification concordance between axial versus coronal/sagittal planes was poor (kappa = -0.09 and -0.07, resp., P planes. Conclusion. Classification of "enlarged" lymph nodes differs between axial versus coronal/sagittal imaging planes when axial-based nodal size criteria are applied independently to all three imaging planes, and exclusively used without other morphologic nodal data.

  20. A two-wavelength imaging pyrometer for measuring particle temperature, velocity and size in thermal spray processes

    International Nuclear Information System (INIS)

    Craig, J.E.; Parker, R.A.; Lee, D.Y.; Biancaniello, F.; Ridder, S.

    1999-01-01

    An imaging pyrometer has been developed to measure the surface temperature of hot metal objects and to measure particle temperature, velocity and size in thermal spray, spray-fonning and atomization processes. The two-wavelength surface imaging pyrometer provides true temperature measurement with high resolution, even when the surface has emissivity variation caused by roughness or oxidation. The surface imaging pyrometer has been calibrated for use in a material processing lab calibration over the range of 1000 to 3000 deg K, and these results are described. The particle imaging pyrometer has a field of view that spans the entire particle stream in typical thermal spray devices, and provides continuous measurement of the entire particle stream. Particle temperature and velocity are critical parameters for producing high quality spray coatings efficiently and reliably. The software locates the particle streaks in the image, and determines the intensity ratio for each particle streak pair to obtain the temperature. The dimensions of the particle streak image are measured to determine the velocity and size. Because the vision-based sensor samples the entire particle stream in every video frame, the particle temperature, velocity and size data are updated at 30 Hz at all points in the particle stream. Particle measurements in a plasma spray at NIST are described. In this paper, we will describe our experiments with ceramic powders, in which measurements have been made at several positions along the particle stream. The particle data are represented as profiles across the particle stream, histograms of the full particle stream or time histories of the full-stream average. The results are compared and calibrated with other temperature and diagnostic measurement systems. (author)

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